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Thilakarathna SH, Li V, Chui L. A challenging STEC strain isolation from patients' stools: an O166:H15 STEC strain with the stx2 gene. Microbiol Spectr 2024; 12:e0009824. [PMID: 38814093 PMCID: PMC11218488 DOI: 10.1128/spectrum.00098-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 04/25/2024] [Indexed: 05/31/2024] Open
Abstract
Two patients with acute gastroenteritis tested positive for Shiga toxin-producing Escherichia coli (STEC) by polymerase chain reaction (PCR), and both strains carried the Shiga toxin 2 encoding gene. Since routine culture using CHROMagar STEC failed to recover these isolates, immunomagnetic separation (IMS) targeting the top six non-O157:H7 serotypes was used for isolate recovery. After two subsequent IMS runs, the STEC strains were isolated from trypticase soy broth with and without overnight enrichment for runs 1 and 2, respectively. Serotyping based on whole-genome sequencing revealed that both patients carried the strain O166:H15 STEC with the stx2 gene. Hence, the magnetic beads used in IMS appeared to have cross-reactivity with other E. coli serotypes. When the STEC isolates from both stools were cultured on CHROMagar STEC and sheep blood agar (BAP), two distinct colony sizes were apparent after overnight incubation. The small and large colonies were picked and separately cultured on both media, and colony growth was observed for 2 weeks at room temperature after an initial overnight incubation at 37°C. After 1 week, the colonies showed concentric ring structures with a darker center and a lighter surrounding on CHROMagar STEC and a "fried egg"-resembling structure with a raised circular center and a flat surrounding on BAP. Both colony types remained morphologically different on CHROMagar STEC throughout the 15 days. However, on BAP, their appearance was comparable by day 7. IMPORTANCE Shiga toxin-producing E. coli (STEC) infections can lead to severe complications such as bloody diarrhea and hemolytic uremic syndrome (HUS), especially in young children and the elderly. Strains that carry the shiga toxin 2 gene (stx2), such as O157:H7, have been mostly linked with severe disease outcomes. In recent years, outbreaks caused by non-O157:H7 strains have increased. E. coli O166:H15 has been previously reported causing a gastroenteritis outbreak in 1996 as a non-STEC strain, however the O166:H15 serotype we recovered carried the stx2 gene. It was particularly challenging to isolate this strain from stools by culture. Consequently, we tested immunomagnetic separation for the STEC recovery, which was a novel approach on clinical stools. Virulence genes were included for the characterization of these isolates.
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Affiliation(s)
- Surangi H. Thilakarathna
- Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
| | - Vincent Li
- Alberta Precision Laboratories - Public Health Laboratory (ProvLab), Edmonton, Canada
| | - Linda Chui
- Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
- Alberta Precision Laboratories - Public Health Laboratory (ProvLab), Edmonton, Canada
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2
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Ravishankar S, Baldelli V, Angeletti C, Raffaelli N, Landini P, Rossi E. Fluoropyrimidines affect de novo pyrimidine synthesis impairing biofilm formation in Escherichia coli. Biofilm 2024; 7:100180. [PMID: 38370152 PMCID: PMC10869245 DOI: 10.1016/j.bioflm.2024.100180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 01/24/2024] [Accepted: 01/29/2024] [Indexed: 02/20/2024] Open
Abstract
Antivirulence agents are considered a promising strategy to treat bacterial infections. Fluoropyrimidines possess antivirulence and antibiofilm activity against Gram-negative bacteria; however, their mechanism of action is yet unknown. Consistent with their known antibiofilm activity, fluoropyrimidines, particularly 5-fluorocytosine (5-FC), impair curli-dependent surface adhesion by Escherichia coli MG1655 via downregulation of curli fimbriae gene transcription. Curli inhibition requires fluoropyrimidine conversion into fluoronucleotides and is not mediated by c-di-GMP or the ymg-rcs envelope stress response axis, previously suggested as the target of fluorouracil antibiofilm activity in E. coli. In contrast, 5-FC hampered the transcription of curli activators RpoS and stimulated the expression of Fis, a curli repressor affected by nucleotide availability. This last observation suggested a possible perturbation of the de novo pyrimidine biosynthesis by 5-FC: indeed, exposure to 5-FC resulted in a ca. 2-fold reduction of UMP intracellular levels while not affecting ATP. Consistently, expression of the de novo pyrimidine biosynthesis genes carB and pyrB was upregulated in the presence of 5-FC. Our results suggest that the antibiofilm activity of fluoropyrimidines is mediated, at least in part, by perturbation of the pyrimidine nucleotide pool. We screened a genome library in search of additional determinants able to counteract the effects of 5-FC. We found that a DNA fragment encoding the unknown protein D8B36_18,480 and the N-terminal domain of the penicillin-binding protein 1b (PBP1b), involved in peptidoglycan synthesis, could restore curli production in the presence of 5-FC. Deletion of the PBP1b-encoding gene mrcB, induced csgBAC transcription, while overexpression of the gene encoding the D8B36_18,480 protein obliterated its expression, possibly as part of a coordinated response in curli regulation with PBP1b. While the two proteins do not appear to be direct targets of 5-FC, their involvement in curli regulation suggests a connection between peptidoglycan biosynthesis and curli production, which might become even more relevant upon pyrimidine starvation and reduced availability of UDP-sugars needed in cell wall biosynthesis. Overall, our findings link the antibiofilm activity of fluoropyrimidines to the redirection of at least two global regulators (RpoS, Fis) by induction of pyrimidine starvation. This highlights the importance of the de novo pyrimidines biosynthesis pathway in controlling virulence mechanisms in different bacteria and makes the pathway a potential target for antivirulence strategies.
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Affiliation(s)
| | | | - Carlo Angeletti
- Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University, Italy
| | - Nadia Raffaelli
- Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University, Italy
| | - Paolo Landini
- Department of Biosciences, University of Milan, Milan, Italy
| | - Elio Rossi
- Department of Biosciences, University of Milan, Milan, Italy
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3
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Nhu NTK, Rahman MA, Goh KGK, Kim SJ, Phan MD, Peters KM, Alvarez-Fraga L, Hancock SJ, Ravi C, Kidd TJ, Sullivan MJ, Irvine KM, Beatson SA, Sweet MJ, Irwin AD, Vukovic J, Ulett GC, Hasnain SZ, Schembri MA. A convergent evolutionary pathway attenuating cellulose production drives enhanced virulence of some bacteria. Nat Commun 2024; 15:1441. [PMID: 38383596 PMCID: PMC10881479 DOI: 10.1038/s41467-024-45176-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Accepted: 01/16/2024] [Indexed: 02/23/2024] Open
Abstract
Bacteria adapt to selective pressure in their immediate environment in multiple ways. One mechanism involves the acquisition of independent mutations that disable or modify a key pathway, providing a signature of adaptation via convergent evolution. Extra-intestinal pathogenic Escherichia coli (ExPEC) belonging to sequence type 95 (ST95) represent a global clone frequently associated with severe human infections including acute pyelonephritis, sepsis, and neonatal meningitis. Here, we analysed a publicly available dataset of 613 ST95 genomes and identified a series of loss-of-function mutations that disrupt cellulose production or its modification in 55.3% of strains. We show the inability to produce cellulose significantly enhances ST95 invasive infection in a rat model of neonatal meningitis, leading to the disruption of intestinal barrier integrity in newborn pups and enhanced dissemination to the liver, spleen and brain. Consistent with these observations, disruption of cellulose production in ST95 augmented innate immune signalling and tissue neutrophil infiltration in a mouse model of urinary tract infection. Mutations that disrupt cellulose production were also identified in other virulent ExPEC STs, Shigella and Salmonella, suggesting a correlative association with many Enterobacteriaceae that cause severe human infection. Together, our findings provide an explanation for the emergence of hypervirulent Enterobacteriaceae clones.
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Affiliation(s)
- Nguyen Thi Khanh Nhu
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, QLD, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - M Arifur Rahman
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
- Immunopathology Group, Mater Research Institute, The University of Queensland, Translational Research Institute, Brisbane, Australia
- QIMR Berghofer Medical Research Institute, Brisbane QLD, Australia
| | - Kelvin G K Goh
- School of Pharmacy and Medical Sciences, Griffith University, Southport, QLD, Australia
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia
| | - Seung Jae Kim
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Minh-Duy Phan
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, QLD, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Kate M Peters
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, QLD, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Laura Alvarez-Fraga
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
- INRAE, Univ Montpellier, LBE, 102 Avenue des Etangs, Narbonne, 11100, France
| | - Steven J Hancock
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK
| | - Chitra Ravi
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, QLD, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Timothy J Kidd
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
- Central Microbiology, Pathology Queensland, Royal Brisbane and Women's Hospital, Brisbane, Australia
| | - Matthew J Sullivan
- School of Pharmacy and Medical Sciences, Griffith University, Southport, QLD, Australia
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Katharine M Irvine
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
- Immunopathology Group, Mater Research Institute, The University of Queensland, Translational Research Institute, Brisbane, Australia
| | - Scott A Beatson
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Matthew J Sweet
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, QLD, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Adam D Irwin
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
- University of Queensland Centre for Clinical Research, Brisbane, Australia
- Queensland Children's Hospital, Brisbane, Australia
| | - Jana Vukovic
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia.
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia.
| | - Glen C Ulett
- School of Pharmacy and Medical Sciences, Griffith University, Southport, QLD, Australia.
- Menzies Health Institute Queensland, Griffith University, Southport, QLD, Australia.
| | - Sumaira Z Hasnain
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia.
- Immunopathology Group, Mater Research Institute, The University of Queensland, Translational Research Institute, Brisbane, Australia.
| | - Mark A Schembri
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, QLD, Australia.
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia.
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Visser JA, Yager D, Chambers SA, Lim JY, Cao X, Cegelski L. Nordihydroguaiaretic Acid (NDGA) Inhibits CsgA Polymerization, Bacterial Amyloid Biogenesis, and Biofilm Formation. Chembiochem 2023; 24:e202300266. [PMID: 37195016 DOI: 10.1002/cbic.202300266] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 05/13/2023] [Accepted: 05/15/2023] [Indexed: 05/18/2023]
Abstract
Escherichia coli and other Enterobacteriaceae thrive in robust biofilm communities through the coproduction of curli amyloid fibers and phosphoethanolamine cellulose. Curli promote adhesion to abiotic surfaces and plant and human host tissues and are associated with pathogenesis in urinary tract infection and food-borne illness. The production of curli in the host has also been implicated in the pathogenesis of neurodegenerative diseases. We report that the natural product nordihydroguaiaretic acid (NDGA) is effective as a curlicide in E. coli. NDGA prevents CsgA polymerization in vitro in a dose-dependent manner. NDGA selectively inhibits cell-associated curli assembly and inhibits uropathogenic E. coli biofilm formation. More broadly, this work emphasizes the ability to evaluate and identify bioactive amyloid assembly inhibitors by using the powerful gene-directed amyloid biogenesis machinery in E. coli.
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Affiliation(s)
- Joshua A Visser
- Department of Chemistry, Stanford University, 380 Roth Way, Keck Building, Stanford, CA, 94305, USA
| | - Deborah Yager
- Department of Chemistry, Stanford University, 380 Roth Way, Keck Building, Stanford, CA, 94305, USA
| | - Schuyler A Chambers
- Department of Chemistry, Stanford University, 380 Roth Way, Keck Building, Stanford, CA, 94305, USA
| | - Ji Youn Lim
- Department of Chemistry, Stanford University, 380 Roth Way, Keck Building, Stanford, CA, 94305, USA
| | - Xujun Cao
- Department of Chemistry, Stanford University, 380 Roth Way, Keck Building, Stanford, CA, 94305, USA
| | - Lynette Cegelski
- Department of Chemistry, Stanford University, 380 Roth Way, Keck Building, Stanford, CA, 94305, USA
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5
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Cimdins-Ahne A, Naemi AO, Li F, Simm R, Römling U. Characterisation of Variants of Cyclic di-GMP Turnover Proteins Associated with Semi-Constitutive rdar Morphotype Expression in Commensal and Uropathogenic Escherichia coli Strains. Microorganisms 2023; 11:2048. [PMID: 37630608 PMCID: PMC10459773 DOI: 10.3390/microorganisms11082048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 08/01/2023] [Accepted: 08/07/2023] [Indexed: 08/27/2023] Open
Abstract
Expression of rdar (red, dry, and rough) colony morphology-based biofilm formation in Escherichia coli is highly variable. To investigate the molecular mechanisms of semi-constitutive rdar morphotype formation, we compared their cyclic di-GMP turnover protein content and variability to the highly regulated, temperature-dependent morphotype of the historical and modern ST10 isolates E. coli MG1655 and Fec10, respectively. Subsequently, we assessed the effects of cyclic di-GMP turnover protein variants of the EAL phosphodiesterases YcgG and YjcC and the horizontally transferred diguanylate cyclase DgcX on biofilm formation and motility. The two YcgG variants with truncations of the N-terminal CSS signaling domain were oppositely effective in targeting downregulation of rdar biofilm formation compared to the full-length reference protein. Expression of the C-terminal truncated variants YjcCFec67 and YjcCTob1 showed highly diminished apparent phosphodiesterase activity compared to the reference YjcCMG1655. For YjcCFec101, substitution of the C-terminus led to an apparently inactive enzyme. Overexpression of the diguanylate cyclase DgcX contributed to upregulation of cellulose biosynthesis but not to elevated expression of the major biofilm regulator csgD in the "classical" rdar-expressing commensal strain E. coli Fec10. Thus, the c-di-GMP regulating network is highly complex with protein variants displaying substantially different apparent enzymatic activities.
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Affiliation(s)
- Annika Cimdins-Ahne
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77 Stockholm, Sweden; (A.C.-A.); (F.L.)
| | - Ali-Oddin Naemi
- Institute of Oral Biology, University of Oslo, 0313 Oslo, Norway; (A.-O.N.); (R.S.)
| | - Fengyang Li
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77 Stockholm, Sweden; (A.C.-A.); (F.L.)
| | - Roger Simm
- Institute of Oral Biology, University of Oslo, 0313 Oslo, Norway; (A.-O.N.); (R.S.)
- Norwegian Veterinary Institute, 0106 Oslo, Norway
| | - Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 171 77 Stockholm, Sweden; (A.C.-A.); (F.L.)
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6
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Amemiya K, Rozak DA, Dankmeyer JL, Dorman WR, Marchand C, Fetterer DP, Worsham PL, Purcell BK. Shiga-Toxin-Producing Strains of Escherichia coli O104:H4 and a Strain of O157:H7, Which Can Cause Human Hemolytic Uremic Syndrome, Differ in Biofilm Formation in the Presence of CO 2 and in Their Ability to Grow in a Novel Cell Culture Medium. Microorganisms 2023; 11:1744. [PMID: 37512916 PMCID: PMC10384166 DOI: 10.3390/microorganisms11071744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/13/2023] [Accepted: 06/27/2023] [Indexed: 07/30/2023] Open
Abstract
One pathogen that commonly causes gastrointestinal illnesses from the consumption of contaminated food is Escherichia coli O157:H7. In 2011 in Germany, however, there was a prominent outbreak of bloody diarrhea with a high incidence of hemolytic uremic syndrome (HUS) caused by an atypical, more virulent E. coli O104:H4 strain. To facilitate the identification of this lesser-known, atypical E. coli O104:H4 strain, we wanted to identify phenotypic differences between it and a strain of O157:H7 in different media and culture conditions. We found that E. coli O104:H4 strains produced considerably more biofilm than the strain of O157:H7 at 37 °C (p = 0.0470-0.0182) Biofilm production was significantly enhanced by the presence of 5% CO2 (p = 0.0348-0.0320). In our study on the innate immune response to the E. coli strains, we used HEK293 cells that express Toll-like receptors (TLRs) 2 or 4. We found that E. coli O104:H4 strains had the ability to grow in a novel HEK293 cell culture medium, while the E. coli O157:H7 strain could not. Thus, we uncovered previously unknown phenotypic properties of E. coli O104:H4 to further differentiate this pathogen from E. coli O157:H7.
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Affiliation(s)
- Kei Amemiya
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702, USA
| | - David A Rozak
- Diagnostic Systems Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702, USA
| | - Jennifer L Dankmeyer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702, USA
| | - William R Dorman
- Diagnostic Systems Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702, USA
| | - Charles Marchand
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702, USA
| | - David P Fetterer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702, USA
| | - Patricia L Worsham
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702, USA
| | - Brett K Purcell
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702, USA
- Department of Medicine, University of Florida, Orlando, FL 32816, USA
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7
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Römling U, Cao LY, Bai FW. Evolution of cyclic di-GMP signalling on a short and long term time scale. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001354. [PMID: 37384391 PMCID: PMC10333796 DOI: 10.1099/mic.0.001354] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 06/13/2023] [Indexed: 07/01/2023]
Abstract
Diversifying radiation of domain families within specific lineages of life indicates the importance of their functionality for the organisms. The foundation for the diversifying radiation of the cyclic di-GMP signalling network that occurred within the bacterial kingdom is most likely based in the outmost adaptability, flexibility and plasticity of the system. Integrative sensing of multiple diverse extra- and intracellular signals is made possible by the N-terminal sensory domains of the modular cyclic di-GMP turnover proteins, mutations in the protein scaffolds and subsequent signal reception by diverse receptors, which eventually rewires opposite host-associated as well as environmental life styles including parallel regulated target outputs. Natural, laboratory and microcosm derived microbial variants often with an altered multicellular biofilm behaviour as reading output demonstrated single amino acid substitutions to substantially alter catalytic activity including substrate specificity. Truncations and domain swapping of cyclic di-GMP signalling genes and horizontal gene transfer suggest rewiring of the network. Presence of cyclic di-GMP signalling genes on horizontally transferable elements in particular observed in extreme acidophilic bacteria indicates that cyclic di-GMP signalling and biofilm components are under selective pressure in these types of environments. On a short and long term evolutionary scale, within a species and in families within bacterial orders, respectively, the cyclic di-GMP signalling network can also rapidly disappear. To investigate variability of the cyclic di-GMP signalling system on various levels will give clues about evolutionary forces and discover novel physiological and metabolic pathways affected by this intriguing second messenger signalling system.
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Affiliation(s)
- Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Lian-Ying Cao
- Department of Microbiology, Tumor and Cell Biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, PR China
| | - Feng-Wu Bai
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, PR China
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8
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Ortiz Y, Heredia N, García S. Boundaries That Prevent or May Lead Animals to be Reservoirs of Escherichia coli O104:H4. J Food Prot 2023; 86:100053. [PMID: 36916560 DOI: 10.1016/j.jfp.2023.100053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 01/18/2023] [Accepted: 01/21/2023] [Indexed: 02/05/2023]
Abstract
Escherichia coli O104:H4, a hybrid serotype carrying virulence factors from enteroaggregative (EAEC) and Shiga toxin-producing (STEC) pathotypes, is the reported cause of a multicountry outbreak in 2011. Evaluation of potential routes of human contamination revealed that this strain is a foodborne pathogen. In contrast to STEC strains, whose main reservoir is cattle, serotype O104:H4 has not been commonly isolated from animals or related environments, suggesting an inability to naturally colonize the gut in hosts other than humans. However, contrary to this view, this strain has been shown to colonize the intestines of experimental animals in infectious studies. In this minireview, we provide a systematic summary of reports highlighting potential evolutionary changes that could facilitate the colonization of new reservoirs by these bacteria.
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Affiliation(s)
- Yaraymi Ortiz
- Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Ciudad Universitaria, San Nicolás de los Garza, NL 66455, Mexico
| | - Norma Heredia
- Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Ciudad Universitaria, San Nicolás de los Garza, NL 66455, Mexico
| | - Santos García
- Departamento de Microbiología e Inmunología, Facultad de Ciencias Biológicas, Universidad Autónoma de Nuevo León, Ciudad Universitaria, San Nicolás de los Garza, NL 66455, Mexico.
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9
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Stepanov D, Buchmann D, Schultze N, Wolber G, Schaufler K, Guenther S, Belik V. A Combined Bayesian and Similarity-Based Approach for Predicting E. coli Biofilm Inhibition by Phenolic Natural Compounds. JOURNAL OF NATURAL PRODUCTS 2022; 85:2255-2265. [PMID: 36107719 DOI: 10.1021/acs.jnatprod.2c00005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Screening for biofilm inhibition by purified natural compounds is difficult due to compounds' chemical diversity and limited commercial availability, combined with time- and cost-intensiveness of the laboratory process. In silico prediction of chemical and biological properties of molecules is a widely used technique when experimental data availability is of concern. At the same time, the performance of predictive models directly depends on the amount and quality of experimental data. Driven by the interest in developing a model for prediction of the antibiofilm effect of phenolic natural compounds such as flavonoids, we performed experimental assessment of antibiofilm activity of 320 compounds from this subset of chemicals. The assay was performed once on two Escherichia coli strains on agar in 24-well microtiter plates. The inhibition was assessed visually by detecting morphological changes in macrocolonies. Using the data obtained, we subsequently trained a Bayesian logistic regression model for prediction of biofilm inhibition, which was combined with a similarity-based method in order to increase the overall sensitivity (at the cost of accuracy). The quality of the predictions was subsequently validated by experimental assessment in three independent experiments with two resistant E. coli strains of 23 compounds absent in the initial data set. The validation demonstrated that the model may successfully predict the targeted effect as compared to the baseline accuracy. Using a randomly selected database of commercially available natural phenolics, we obtained approximately 6.0% of active compounds, whereas using our prediction-based substance selection, the percentage of phenolics found to be active increased to 34.8%.
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Affiliation(s)
- Dmitri Stepanov
- Department of Biology, Chemistry & Pharmacy, Institute of Pharmacy, Pharmaceutical and Medicinal Chemistry, Freie Universität Berlin, Königin-Luise-Straße 2+4, 14195 Berlin, Germany
| | - David Buchmann
- Pharmaceutical Biology, Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Straße 17, 17489 Greifswald, Germany
| | - Nadin Schultze
- Pharmaceutical Biology, Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Straße 17, 17489 Greifswald, Germany
| | - Gerhard Wolber
- Department of Biology, Chemistry & Pharmacy, Institute of Pharmacy, Pharmaceutical and Medicinal Chemistry, Freie Universität Berlin, Königin-Luise-Straße 2+4, 14195 Berlin, Germany
| | - Katharina Schaufler
- Pharmaceutical Microbiology, Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Straße 17, 17489 Greifswald, Germany
- Institute of Infection Medicine, Christian-Albrecht University Kiel and University Medical Center Schleswig-Holstein, 24105 Kiel, Germany
| | - Sebastian Guenther
- Pharmaceutical Biology, Institute of Pharmacy, University of Greifswald, Friedrich-Ludwig-Jahn-Straße 17, 17489 Greifswald, Germany
| | - Vitaly Belik
- Department of Veterinary Medicine, Institute for Veterinary Epidemiology and Biostatistics, System Modeling Group, Freie Universität Berlin, Königsweg 67, 14163 Berlin, Germany
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10
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Abstract
Shigella flexneri is an intracellular human pathogen that invades colonic cells and causes bloody diarrhea. S. flexneri evolved from commensal Escherichia coli, and genome comparisons reveal that S. flexneri has lost approximately 20% of its genes through the process of pathoadaptation, including a disproportionate number of genes associated with the turnover of the nucleotide-based second messenger cyclic di-GMP (c-di-GMP); however, the remaining c-di-GMP turnover enzymes are highly conserved. c-di-GMP regulates many behavioral changes in other bacteria in response to changing environmental conditions, including biofilm formation, but this signaling system has not been examined in S. flexneri. In this study, we expressed VCA0956, a constitutively active c-di-GMP synthesizing diguanylate cyclase (DGC) from Vibrio cholerae, in S. flexneri to determine if virulence phenotypes were regulated by c-di-GMP. We found that expressing VCA0956 in S. flexneri increased c-di-GMP levels, and this corresponds with increased biofilm formation and reduced acid resistance, host cell invasion, and plaque size. We examined the impact of VCA0956 expression on the S. flexneri transcriptome and found that genes related to acid resistance were repressed, and this corresponded with decreased survival to acid shock. We also found that individual S. flexneri DGC mutants exhibit reduced biofilm formation and reduced host cell invasion and plaque size, as well as increased resistance to acid shock. This study highlights the importance of c-di-GMP signaling in regulating S. flexneri virulence phenotypes. IMPORTANCE The intracellular human pathogen Shigella causes dysentery, resulting in as many as one million deaths per year. Currently, there is no approved vaccine for the prevention of shigellosis, and the incidence of antimicrobial resistance among Shigella species is on the rise. Here, we explored how the widely conserved c-di-GMP bacterial signaling system alters Shigella behaviors associated with pathogenesis. We found that expressing or removing enzymes associated with c-di-GMP synthesis results in changes in Shigella's ability to form biofilms, invade host cells, form lesions in host cell monolayers, and resist acid stress.
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11
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Serra DO, Hengge R. Bacterial Multicellularity: The Biology of Escherichia coli Building Large-Scale Biofilm Communities. Annu Rev Microbiol 2021; 75:269-290. [PMID: 34343018 DOI: 10.1146/annurev-micro-031921-055801] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Biofilms are a widespread multicellular form of bacterial life. The spatial structure and emergent properties of these communities depend on a polymeric extracellular matrix architecture that is orders of magnitude larger than the cells that build it. Using as a model the wrinkly macrocolony biofilms of Escherichia coli, which contain amyloid curli fibers and phosphoethanolamine (pEtN)-modified cellulose as matrix components, we summarize here the structure, building, and function of this large-scale matrix architecture. Based on different sigma and other transcription factors as well as second messengers, the underlying regulatory network reflects the fundamental trade-off between growth and survival. It controls matrix production spatially in response to long-range chemical gradients, but it also generates distinct patterns of short-range matrix heterogeneity that are crucial for tissue-like elasticity and macroscopic morphogenesis. Overall, these biofilms confer protection and a potential for homeostasis, thereby reducing maintenance energy, which makes multicellularity an emergent property of life itself. Expected final online publication date for the Annual Review of Microbiology, Volume 75 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Diego O Serra
- Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Rosario (UNR), 2000 Rosario, Argentina
| | - Regine Hengge
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, 10115 Berlin, Germany;
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12
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The deletion of yeaJ gene facilitates Escherichia coli escape from immune recognition. J Bacteriol 2021; 203:e0033621. [PMID: 34309400 DOI: 10.1128/jb.00336-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mammary gland-derived Escherichia coli (E. coli) is an important pathogen causing dairy cow mastitis. Mammary gland mucosal immunity against infectious E. coli mainly depends on recognition of pathogen-associated molecular patterns by innate receptors. Stimulator of interferon (IFN) gene (STING) has recently been the dominant mediator in reacting to bacterial intrusion and preventing inflammatory disorders. In this study, we firstly proved that diguanylate cyclase YeaJ relieves mouse mammary gland pathological damage by changing E. coli phenotypic and host STING-dependent innate immunity response. YeaJ decreases mammary gland circular vacuoles, bleeding and degeneration in mice. In addition, YeaJ participates in STING-IRF3 signaling to regulate inflammation in vivo. While in vitro, YeaJ decreases damage to macrophages (RAW264.7) but not to mouse mammary epithelial cells (EpH4-Ev). Consistent with the results in mouse mammary gland, yeaJ significantly activates STING/TBK1/IRF3 pathway in RAW264.7 as well. In conclusion, the deletion of yeaJ gene facilitates E. coli NJ17 escape from STING-dependent innate immunity recognition in vitro and in vivo. This study highlights a novel role for YeaJ in E. coli infection, which provides a better understanding of host-bacteria interactions and potential prophylactic strategies for infections. IMPORTANCE E. coli is the etiological agent of environmental mastitis in dairy cows, which cause massive financial losses worldwide. However, the pathophysiological role of yeaJ in the interaction between E. coli and host remains unclear. We found that YeaJ significantly influences various biological characteristics and suppresses severe inflammatory response as well as greater damage. YeaJ alleviates damage to macrophages (RAW264.7) and mouse mammary gland. Moreover, these effects of YeaJ are achieved at least partial by mediating the STING-IRF3 signaling pathway. In conclusion, the deletion of yeaJ gene facilitates E. coli NJ17 escape from STING-dependent innate immunity recognition in vitro and in vivo. This study is the basis for further research to better understand host-bacteria interactions and provides potential prophylactic strategies for infections.
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13
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Wahlig TA, Stanton E, Godfrey JJ, Stasic AJ, Wong ACL, Kaspar CW. A Single Nucleotide Polymorphism in lptG Increases Tolerance to Bile Salts, Acid, and Staining of Calcofluor-Binding Polysaccharides in Salmonella enterica Serovar Typhimurium E40. Front Microbiol 2021; 12:671453. [PMID: 34149657 PMCID: PMC8208086 DOI: 10.3389/fmicb.2021.671453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 04/12/2021] [Indexed: 11/13/2022] Open
Abstract
The outer membrane of Salmonella enterica plays an important role in combating stress encountered in the environment and hosts. The transport and insertion of lipopolysaccharides (LPS) into the outer membrane involves lipopolysaccharide transport proteins (LptA-F) and mutations in the genes encoding for these proteins are often lethal or result in the transport of atypical LPS that can alter stress tolerance in bacteria. During studies of heterogeneity in bile salts tolerance, S. enterica serovar Typhimurium E40 was segregated into bile salts tolerant and sensitive cells by screening for growth in TSB with 10% bile salts. An isolate (E40V) with a bile salts MIC >20% was selected for further characterization. Whole-genome sequencing of E40 and E40V using Illumina and PacBio SMRT technologies revealed a non-synonymous single nucleotide polymorphism (SNP) in lptG. Leucine at residue 26 in E40 was substituted with proline in E40V. In addition to growth in the presence of 10% bile salts, E40V was susceptible to novobiocin while E40 was not. Transcriptional analysis of E40 and E40V, in the absence of bile salts, revealed significantly greater (p < 0.05) levels of transcript in three genes in E40V; yjbE (encoding for an extracellular polymeric substance production protein), yciE (encoding for a putative stress response protein), and an uncharacterized gene annotated as an acid shock protein precursor (ASPP). No transcripts of genes were present at a greater level in E40 compared to E40V. Corresponding with the greater level of these transcripts, E40V had greater survival at pH 3.35 and staining of Calcofluor-binding polysaccharide (CBPS). To confirm the SNP in lptG was associated with these phenotypes, strain E40E was engineered from E40 to encode for the variant form of LptG (L26P). E40E exhibited the same differences in gene transcripts and phenotypes as E40V, including susceptibility to novobiocin, confirming the SNP was responsible for these differences.
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Affiliation(s)
- Taylor A Wahlig
- Department of Bacteriology, University of Wisconsin, Madison, WI, United States
| | - Eliot Stanton
- Department of Bacteriology, University of Wisconsin, Madison, WI, United States
| | - Jared J Godfrey
- Department of Bacteriology, University of Wisconsin, Madison, WI, United States
| | - Andrew J Stasic
- U. S. Food and Drug Administration, Center for Biologics Evaluation and Research, Washington, DC, United States
| | - Amy C L Wong
- Department of Bacteriology, University of Wisconsin, Madison, WI, United States
| | - Charles W Kaspar
- Department of Bacteriology, University of Wisconsin, Madison, WI, United States
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14
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Schulze A, Mitterer F, Pombo JP, Schild S. Biofilms by bacterial human pathogens: Clinical relevance - development, composition and regulation - therapeutical strategies. MICROBIAL CELL (GRAZ, AUSTRIA) 2021; 8:28-56. [PMID: 33553418 PMCID: PMC7841849 DOI: 10.15698/mic2021.02.741] [Citation(s) in RCA: 83] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 01/08/2021] [Accepted: 01/12/2021] [Indexed: 12/19/2022]
Abstract
Notably, bacterial biofilm formation is increasingly recognized as a passive virulence factor facilitating many infectious disease processes. In this review we will focus on bacterial biofilms formed by human pathogens and highlight their relevance for diverse diseases. Along biofilm composition and regulation emphasis is laid on the intensively studied biofilms of Vibrio cholerae, Pseudomonas aeruginosa and Staphylococcus spp., which are commonly used as biofilm model organisms and therefore contribute to our general understanding of bacterial biofilm (patho-)physiology. Finally, therapeutical intervention strategies targeting biofilms will be discussed.
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Affiliation(s)
- Adina Schulze
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria
- A.S. and F.M. contributed equally to this work
| | - Fabian Mitterer
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria
- A.S. and F.M. contributed equally to this work
| | - Joao P. Pombo
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria
| | - Stefan Schild
- Institute of Molecular Biosciences, University of Graz, Humboldtstrasse 50, 8010 Graz, Austria
- BioTechMed Graz, Austria
- Field of Excellence Biohealth – University of Graz, Graz, Austria
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15
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Escherichia coli Serotype O157:H7 PA20R2R Complete Genome Sequence. Microbiol Resour Announc 2020; 9:9/50/e01143-20. [PMID: 33303666 PMCID: PMC7729414 DOI: 10.1128/mra.01143-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli serotype O157:H7 strain 20R2R is a derivative of clinical isolate PA20. Prophage excision from the coding region of a PA20 transcription factor restored RpoS-dependent biofilm formation in 20R2R, providing a model for O157:H7 stress adaptation when transitioning between clinical and environmental settings. We report here the complete 20R2R genome sequence. Escherichia coli serotype O157:H7 strain 20R2R is a derivative of clinical isolate PA20. Prophage excision from the coding region of a PA20 transcription factor restored RpoS-dependent biofilm formation in 20R2R, providing a model for O157:H7 stress adaptation when transitioning between clinical and environmental settings. We report here the complete 20R2R genome sequence.
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16
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Pruteanu M, Hernández Lobato JI, Stach T, Hengge R. Common plant flavonoids prevent the assembly of amyloid curli fibres and can interfere with bacterial biofilm formation. Environ Microbiol 2020; 22:5280-5299. [PMID: 32869465 DOI: 10.1111/1462-2920.15216] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/25/2020] [Accepted: 08/27/2020] [Indexed: 01/01/2023]
Abstract
Like all macroorganisms, plants have to control bacterial biofilm formation on their surfaces. On the other hand, biofilms are highly tolerant against antimicrobial agents and other stresses. Consequently, biofilms are also involved in human chronic infectious diseases, which generates a strong demand for anti-biofilm agents. Therefore, we systematically explored major plant flavonoids as putative anti-biofilm agents using different types of biofilms produced by Gram-negative and Gram-positive bacteria. In Escherichia coli macrocolony biofilms, the flavone luteolin and the flavonols myricetin, morin and quercetin were found to strongly reduce the extracellular matrix. These agents directly inhibit the assembly of amyloid curli fibres by driving CsgA subunits into an off-pathway leading to SDS-insoluble oligomers. In addition, they can interfere with cellulose production by still unknown mechanisms. Submerged biofilm formation, however, is hardly affected. Moreover, the same flavonoids tend to stimulate macrocolony and submerged biofilm formation by Pseudomonas aeruginosa. For Bacillus subtilis, the flavonone naringenin and the chalcone phloretin were found to inhibit growth. Thus, plant flavonoids are not general anti-biofilm compounds but show species-specific effects. However, based on their strong and direct anti-amyloidogenic activities, distinct plant flavonoids may provide an attractive strategy to specifically combat amyloid-based biofilms of some relevant pathogens.
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Affiliation(s)
- Mihaela Pruteanu
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Berlin, 10115, Germany
| | | | - Thomas Stach
- Institut für Biologie/Zoologie, Humboldt-Universität zu Berlin, Berlin, 10115, Germany
| | - Regine Hengge
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Berlin, 10115, Germany
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17
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Andreozzi E, Uhlich GA. PchE Regulation of Escherichia coli O157:H7 Flagella, Controlling the Transition to Host Cell Attachment. Int J Mol Sci 2020; 21:ijms21134592. [PMID: 32605187 PMCID: PMC7369912 DOI: 10.3390/ijms21134592] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 06/24/2020] [Accepted: 06/26/2020] [Indexed: 11/16/2022] Open
Abstract
Shiga toxins and intimate adhesion controlled by the locus of enterocyte effacement are major enterohemorrhagic Escherichia coli (EHEC) virulence factors. Curli fimbriae also contribute to cell adhesion and are essential biofilm components. The transcriptional regulator PchE represses the expression of curli and their adhesion to HEp-2 cells. Past studies indicate that pchE also represses additional adhesins that contribute to HEp-2 cell attachment. In this study, we tested for pchE regulation of several tissue adhesins and their regulators. Three adhesin-encoding genes (eae, lpfA1, fliC) and four master regulators (csgD, stpA, ler, flhDC) were controlled by pchE. pchE over-expression strongly up-regulated fliC but the marked flagella induction reduced the attachment of O157:H7 clinical isolate PA20 to HEp-2 cells, indicating that flagella were blocking cell attachments rather than functioning as an adhesin. Chemotaxis, motor, structural, and regulatory genes in the flagellar operons were all increased by pchE expression, as was PA20 motility. This study identifies new members in the pchE regulon and shows that pchE stimulates flagellar motility while repressing cell adhesion, likely to support EHEC movement to the intestinal surface early in infection. However, induced or inappropriate pchE-dependent flagellar expression could block cell attachments later during disease progression.
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18
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Barth SA, Weber M, Schaufler K, Berens C, Geue L, Menge C. Metabolic Traits of Bovine Shiga Toxin-Producing Escherichia Coli (STEC) Strains with Different Colonization Properties. Toxins (Basel) 2020; 12:toxins12060414. [PMID: 32580365 PMCID: PMC7354573 DOI: 10.3390/toxins12060414] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/10/2020] [Accepted: 06/17/2020] [Indexed: 01/14/2023] Open
Abstract
Cattle harbor Shiga toxin-producing Escherichia coli (STEC) in their intestinal tract, thereby providing these microorganisms with an ecological niche, but without this colonization leading to any clinical signs. In a preceding study, genotypic characterization of bovine STEC isolates unveiled that their ability to colonize cattle persistently (STECper) or only sporadically (STECspo) is more closely associated with the overall composition of the accessory rather than the core genome. However, the colonization pattern could not be unequivocally linked to the possession of classical virulence genes. This study aimed at assessing, therefore, if the presence of certain phenotypic traits in the strains determines their colonization pattern and if these can be traced back to distinctive genetic features. STECspo strains produced significantly more biofilm than STECper when incubated at lower temperatures. Key substrates, the metabolism of which showed a significant association with colonization type, were glyoxylic acid and L-rhamnose, which were utilized by STECspo, but not or only by some STECper. Genomic sequences of the respective glc and rha operons contained mutations and frameshifts in uptake and/or regulatory genes, particularly in STECper. These findings suggest that STECspo conserved features leveraging survival in the environment, whereas the acquisition of a persistent colonization phenotype in the cattle reservoir was accompanied by the loss of metabolic properties and genomic mutations in the underlying genetic pathways.
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Affiliation(s)
- Stefanie A. Barth
- Friedrich-Loeffler-Institut/Federal Research Institute for Animal Health, Institute of Molecular Pathogenesis, Naumburger Str. 96a, 07743 Jena, Germany; (M.W.); (C.B.); (L.G.); (C.M.)
- Correspondence: ; Tel.: +49-3641-804-2270; Fax: +49-3641-804-2482
| | - Michael Weber
- Friedrich-Loeffler-Institut/Federal Research Institute for Animal Health, Institute of Molecular Pathogenesis, Naumburger Str. 96a, 07743 Jena, Germany; (M.W.); (C.B.); (L.G.); (C.M.)
| | - Katharina Schaufler
- Free University Berlin, Institute of Microbiology and Epizootics, Robert-von-Ostertag-Str. 7-13, 14163 Berlin, Germany;
- University of Greifswald, Pharmaceutical Microbiology, Friedrich-Ludwig-Jahn-Str. 17, 17489 Greifswald, Germany
| | - Christian Berens
- Friedrich-Loeffler-Institut/Federal Research Institute for Animal Health, Institute of Molecular Pathogenesis, Naumburger Str. 96a, 07743 Jena, Germany; (M.W.); (C.B.); (L.G.); (C.M.)
| | - Lutz Geue
- Friedrich-Loeffler-Institut/Federal Research Institute for Animal Health, Institute of Molecular Pathogenesis, Naumburger Str. 96a, 07743 Jena, Germany; (M.W.); (C.B.); (L.G.); (C.M.)
| | - Christian Menge
- Friedrich-Loeffler-Institut/Federal Research Institute for Animal Health, Institute of Molecular Pathogenesis, Naumburger Str. 96a, 07743 Jena, Germany; (M.W.); (C.B.); (L.G.); (C.M.)
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19
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Evaluation of Phosphoethanolamine Cellulose Production among Bacterial Communities Using Congo Red Fluorescence. J Bacteriol 2020; 202:JB.00030-20. [PMID: 32312746 DOI: 10.1128/jb.00030-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 04/14/2020] [Indexed: 12/23/2022] Open
Abstract
Bacterial biofilms are surface-associated communities of bacterial cells enmeshed in an extracellular matrix (ECM). The biofilm lifestyle results in physiological heterogeneity across the community, promotes persistence, and protects cells from external insults such as antibiotic treatment. Escherichia coli was recently discovered to produce a chemically modified form of cellulose, phosphoethanolamine (pEtN) cellulose, which contributes to the formation of its extracellular matrix and elaboration of its hallmark wrinkled macrocolony architectures. Both pEtN cellulose and unmodified cellulose bind dyes such as calcofluor white and Congo red (CR). Here, we present the use of CR fluorescence to distinguish between pEtN cellulose and unmodified cellulose producers. We demonstrate the utility of this tool in the evaluation of a uropathogenic E. coli clinical isolate that appeared to produce curli and a cellulosic component but did not exhibit macrocolony wrinkling. We determined that lack of macrocolony wrinkling was attributed to a single-nucleotide mutation and introduction of a stop codon in bcsG, abrogating production of BcsG, the pEtN transferase. Thus, this work underscores the important contribution of the pEtN cellulose modification to the E. coli agar-based macrocolony wrinkling phenotype and introduces a facile approach to distinguish between modified and unmodified cellulose.IMPORTANCE E. coli bacteria produce amyloid fibers, termed curli, and a cellulosic component to assemble biofilm communities. Cellulose is the most abundant biopolymer on Earth, and we recently discovered that the cellulosic component in E. coli biofilms was not standard cellulose, but a newly identified cellulosic polymer, phosphoethanolamine cellulose. Studies involving the biological and functional impact of this cellulose modification among E. coli and other organisms are just beginning. Convenient methods for distinguishing pEtN cellulose from unmodified cellulose in E. coli and for estimating production are needed to facilitate further research. Dissecting the balance of pEtN cellulose and curli production by E. coli commensal strains and clinical isolates will improve our understanding of the host microbiome and of factors contributing to bacterial pathogenesis.
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20
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Valentini M, Filloux A. Multiple Roles of c-di-GMP Signaling in Bacterial Pathogenesis. Annu Rev Microbiol 2020; 73:387-406. [PMID: 31500536 DOI: 10.1146/annurev-micro-020518-115555] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The intracellular signaling molecule cyclic di-GMP (c-di-GMP) regulates the lifestyle of bacteria and controls many key functions and mechanisms. In the case of bacterial pathogens, a wide variety of virulence lifestyle factors have been shown to be regulated by c-di-GMP. Evidence of the importance of this molecule for bacterial pathogenesis has become so great that new antimicrobial agents are tested for their capacity of targeting c-di-GMP signaling. This review summarizes the current knowledge on this topic and reveals its application for the development of new antivirulence intervention strategies.
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Affiliation(s)
- Martina Valentini
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, CH-1211 Geneva 4, Switzerland;
| | - Alain Filloux
- MRC Centre for Molecular Microbiology and Infection, Department of Life Sciences, Imperial College London, SW7 2AZ London, United Kingdom;
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21
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Hengge R. Targeting Bacterial Biofilms by the Green Tea Polyphenol EGCG. Molecules 2019; 24:molecules24132403. [PMID: 31261858 PMCID: PMC6650844 DOI: 10.3390/molecules24132403] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 06/24/2019] [Accepted: 06/25/2019] [Indexed: 12/20/2022] Open
Abstract
Bacterial biofilms are multicellular aggregates in which cells are embedded in an extracellular matrix of self-produced biopolymers. Being refractory to antibiotic treatment and host immune systems, biofilms are involved in most chronic infections, and anti-biofilm agents are being searched for urgently. Epigallocatechin-3-gallate (EGCG) was recently shown to act against biofilms by strongly interfering with the assembly of amyloid fibres and the production of phosphoethanolamin-modified cellulose fibrils. Mechanistically, this includes a direct inhibition of the fibre assembly, but also triggers a cell envelope stress response that down-regulates the synthesis of these widely occurring biofilm matrix polymers. Based on its anti-amyloidogenic properties, EGCG seems useful against biofilms involved in cariogenesis or chronic wound infection. However, EGCG seems inefficient against or may even sometimes promote biofilms which rely on other types of matrix polymers, suggesting that searching for 'magic bullet' anti-biofilm agents is an unrealistic goal. Combining molecular and ecophysiological aspects in this review also illustrates why plants control the formation of biofilms on their surfaces by producing anti-amyloidogenic compounds such as EGCG. These agents are not only helpful in combating certain biofilms in chronic infections but even seem effective against the toxic amyloids associated with neuropathological diseases.
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Affiliation(s)
- Regine Hengge
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, 10155 Berlin, Germany.
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22
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Prateeksha, Barik SK, Singh BN. Nanoemulsion-loaded hydrogel coatings for inhibition of bacterial virulence and biofilm formation on solid surfaces. Sci Rep 2019; 9:6520. [PMID: 31019240 PMCID: PMC6482171 DOI: 10.1038/s41598-019-43016-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 04/15/2019] [Indexed: 12/02/2022] Open
Abstract
The indiscriminate use of antibiotics has led to the emergence of drug-resistant bacteria which has become one of the biggest challenges of the twenty-first century for the researchers to combat and in turn search for novel targets which could lead to the development of effective and sustainable therapies. Inhibition of biofilm formation and virulence of bacterial pathogens is an emerging approach to address the challenges related to bacterial infections. To suppress the virulence and biofilm formation by Escherichia coli O157:H7 (ECOH), we developed stable nanoemulsion (NE) of Gaultheria fragrantissima Wall. essential oil’s (EO) bioactive compounds, viz., eugenol (E-NE) and methyl salicylate (MS-NE) that showed significantly higher anti-biofilm and anti-virulence activities as compared to eugenol and methyl salicylate without affecting ECOH planktonic cell growth. Transcriptional analysis showed that E-NE and MS-NE reduced the expression of genes, including curli, type I fimbriae, Shiga-like toxins, quorum sensing, and ler-controlled toxins, which are needed for biofilm formation, pathogenicity, and attachment. E-NE and MS-NE loaded hydrogel coatings showed superior anti-biofilm activity against ECOH on glass, plastic and meat surfaces as compared to eugenol and methyl salicylate loaded coatings. Conclusively, NE-loaded hydrogel coatings could be used in combating ECOH infection on solid surfaces through anti-biofilm and anti-virulence strategies.
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Affiliation(s)
- Prateeksha
- Herbal Nanobiotechnology Lab, Pharmacology Division, CSIR-National Botanical Research Institute, Lucknow, 226001, India
| | - Saroj Kanta Barik
- Herbal Nanobiotechnology Lab, Pharmacology Division, CSIR-National Botanical Research Institute, Lucknow, 226001, India.
| | - Brahma Nand Singh
- Herbal Nanobiotechnology Lab, Pharmacology Division, CSIR-National Botanical Research Institute, Lucknow, 226001, India.
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23
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Brust FR, Boff L, da Silva Trentin D, Pedrotti Rozales F, Barth AL, Macedo AJ. Macrocolony of NDM-1 Producing Enterobacter hormaechei subsp. oharae Generates Subpopulations with Different Features Regarding the Response of Antimicrobial Agents and Biofilm Formation. Pathogens 2019; 8:pathogens8020049. [PMID: 31014001 PMCID: PMC6631906 DOI: 10.3390/pathogens8020049] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 04/08/2019] [Accepted: 04/11/2019] [Indexed: 11/16/2022] Open
Abstract
Enterobacter cloacae complex has been increasingly recognized as a nosocomial pathogen representing the third major Enterobacteriaceae species involved with infections. This study aims to evaluate virulence and antimicrobial susceptibility of subpopulations generated from macrocolonies of NDM-1 producing Enterobacter hormaechei clinical isolates. Biofilm was quantified using crystal violet method and fimbrial genes were investigated by PCR. Susceptibility of antimicrobials, alone and combined, was determined by minimum inhibitory concentration and checkerboard assays, respectively. Virulence and efficacy of antimicrobials were evaluated in Galleria mellonella larvae. Importantly, we verified that some subpopulations that originate from the same macrocolony present different biofilm production ability and distinct susceptibility to meropenem due to the loss of blaNDM-1 encoding plasmid. A more in-depth study was performed with the 798 macrocolony subpopulations. Type 3 fimbriae were straightly related with biofilm production; however, virulence in larvae was not statistically different among subpopulations. Triple combination with meropenem-rifampicin-polymyxin B showed in vitro synergistic effect against all subpopulations; while in vivo this treatment showed different efficacy rates for 798-1S and 798-4S subpopulations. The ability of multidrug resistant E. hormaechei isolates in generating bacterial subpopulations presenting different susceptible and virulence mechanisms are worrisome and may explain why these infections are hardly overcome.
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Affiliation(s)
- Flávia Roberta Brust
- Faculty of Pharmacy and Center of Biotechnology, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul CE 90610-000, Brazil.
| | - Luana Boff
- Faculty of Pharmacy and Center of Biotechnology, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul CE 90610-000, Brazil.
| | - Danielle da Silva Trentin
- Basic Health Sciences Department, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Rio Grande do Sul CE 90050-170, Brazil.
| | - Franciele Pedrotti Rozales
- Laboratory of Research in Bacterial Resistance, Center for Experimental Research, Clinical Hospital of Porto Alegre, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul CE 90035-007, Brazil.
| | - Afonso Luís Barth
- Laboratory of Research in Bacterial Resistance, Center for Experimental Research, Clinical Hospital of Porto Alegre, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul CE 90035-007, Brazil.
| | - Alexandre José Macedo
- Faculty of Pharmacy and Center of Biotechnology, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul CE 90610-000, Brazil.
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DncV Synthesizes Cyclic GMP-AMP and Regulates Biofilm Formation and Motility in Escherichia coli ECOR31. mBio 2019; 10:mBio.02492-18. [PMID: 30837338 PMCID: PMC6401482 DOI: 10.1128/mbio.02492-18] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The ability of bacteria to sense and respond to environmental signals is critical for survival. Bacteria use cyclic dinucleotides as second messengers to regulate a number of physiological processes, such as the fundamental life style transition between motility and sessility (biofilm formation). cGAMP, which is synthesized by a dinucleotide cyclase called DncV, is a newly discovered second messenger involved in virulence and chemotaxis in the Vibrio cholerae biovar El Tor causing the current 7th cholera pandemic. However, to what extent cGAMP exists and participates in physiological processes in other bacteria is still unknown. In this study, we found an elevated cGAMP level to possibly regulate biofilm formation and motility in the animal commensal E. coli strain ECOR31. Thus, we detected a novel role for cGAMP signaling in regulation of physiological processes other than those previously reported in proteobacterial species. Cyclic dinucleotides (cDNs) act as intracellular second messengers, modulating bacterial physiology to regulate the fundamental life style transition between motility and sessility commonly known as biofilm formation. Cyclic GMP-AMP (cGAMP), synthesized by the dinucleotide cyclase DncV, is a newly discovered cDN second messenger involved in virulence and chemotaxis in Vibrio cholerae O1 biovar El Tor. Here we report a novel role for horizontally transferred DncV in cGAMP production and regulation of biofilm formation and motility in the animal commensal strain Escherichia coli ECOR31. ECOR31 expresses a semiconstitutive temperature-independent rdar (red, dry, and rough) morphotype on Congo red agar plates characterized by the extracellular matrix components cellulose and curli fimbriae which requires activation by the major biofilm regulator CsgD and cyclic di-GMP signaling. In contrast, C-terminal His-tagged DncV negatively regulates the rdar biofilm morphotype and cell aggregation via downregulation of csgD mRNA steady-state level. Furthermore, DncV sequentially promotes and inhibits adhesion to the abiotic surface after 24 h and 48 h of growth, respectively. DncV also suppresses swimming and swarming motility posttranscriptional of the class 1 flagellum regulon gene flhD. Purified DncV produced different cDNs, cyclic di-GMP, cyclic di-AMP, an unknown product(s), and the dominant species 3′3′-cGAMP. In vivo, only the 3′3′-cGAMP concentration was elevated upon short-term overexpression of dncV, making this work a first report on cGAMP production in E. coli. Regulation of rdar biofilm formation and motility upon overexpression of untagged DncV in combination with three adjacent cotransferred gene products suggests a novel temperature-dependent cGAMP signaling module in E. coli ECOR31.
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Andreozzi E, Gunther NW, Reichenberger ER, Rotundo L, Cottrell BJ, Nuñez A, Uhlich GA. Pch Genes Control Biofilm and Cell Adhesion in a Clinical Serotype O157:H7 Isolate. Front Microbiol 2018; 9:2829. [PMID: 30532745 PMCID: PMC6265319 DOI: 10.3389/fmicb.2018.02829] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 11/05/2018] [Indexed: 01/06/2023] Open
Abstract
In a previous study, induction of the Escherichia coli serotype O157:H7 SOS response decreased csgD expression in the clinical isolate PA20 at 30°C but strongly induced genes in the horizontally transferred-DNA regions (HTR), including many known virulence regulators. To determine the role of HTR regulators in the control of csgD and curli, specific regulators were plasmid-expressed in the wild-type and mutant strains of PA20 and its biofilm-forming derivative, 20R2R. At 30°C, plasmid over-expression of the O157:H7 group 3 perC homolog, pchE, strongly repressed PA20 csgD transcription (>7-fold) while the group 1 homologs, pchA and pchB, resulted in smaller reductions (<2.5-fold). However, SOS induction decreased rather than increased pchE expression (>6-fold) making group 1 pch, which are enhanced by the SOS response, the likely SOS-induced csgD repressors. Plasmid-based pchE over-expression also reduced 20R2R biofilm formation (>6-fold) and the curli-dependent, Congo red affinity of both PA20 and 20R2R. However, to properly appreciate the regulatory direction, expression patterns, and environmental consequences of these and other CsgD-controlled functions, a better understanding of natural pchE regulation will be required. The effects of HTR regulators on PA20 and 20R2R adhesion to HEp-2 cell at host temperature were also studied. Under conditions where prophage genes were not induced, curli, rather than espA, contributed to host cell adhesion in strain 20R2R. High levels of pchE expression in trans reduced curli-dependent cell adherence (>2-fold) to both 20R2R and the clinical isolate PA20, providing a host-adapting adhesion control mechanism. Expression of pchE was also repressed by induction of the SOS response at 37°C, providing a mechanism by which curli expression might complement EspA-dependent intimate adhesion initiated by the group1 pch homologs. This study has increased our understanding of the O157 pch genes at both host and environment temperatures, identifying pchE as a strong regulator of csgD and CsgD-dependent properties.
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Affiliation(s)
- Elisa Andreozzi
- Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Wyndmoor, PA, United States
| | - Nereus W Gunther
- Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Wyndmoor, PA, United States
| | - Erin R Reichenberger
- Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Wyndmoor, PA, United States
| | - Luca Rotundo
- Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Wyndmoor, PA, United States
| | - Bryan J Cottrell
- Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Wyndmoor, PA, United States
| | - Alberto Nuñez
- Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Wyndmoor, PA, United States
| | - Gaylen A Uhlich
- Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Wyndmoor, PA, United States
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Hollenbeck EC, Antonoplis A, Chai C, Thongsomboon W, Fuller GG, Cegelski L. Phosphoethanolamine cellulose enhances curli-mediated adhesion of uropathogenic Escherichia coli to bladder epithelial cells. Proc Natl Acad Sci U S A 2018; 115:10106-10111. [PMID: 30232265 PMCID: PMC6176564 DOI: 10.1073/pnas.1801564115] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Uropathogenic Escherichia coli (UPEC) are the major causative agents of urinary tract infections, employing numerous molecular strategies to contribute to adhesion, colonization, and persistence in the bladder niche. Identifying strategies to prevent adhesion and colonization is a promising approach to inhibit bacterial pathogenesis and to help preserve the efficacy of available antibiotics. This approach requires an improved understanding of the molecular determinants of adhesion to the bladder urothelium. We designed experiments using a custom-built live cell monolayer rheometer (LCMR) to quantitatively measure individual and combined contributions of bacterial cell surface structures [type 1 pili, curli, and phosphoethanolamine (pEtN) cellulose] to bladder cell adhesion. Using the UPEC strain UTI89, isogenic mutants, and controlled conditions for the differential production of cell surface structures, we discovered that curli can promote stronger adhesive interactions with bladder cells than type 1 pili. Moreover, the coproduction of curli and pEtN cellulose enhanced adhesion. The LCMR enables the evaluation of adhesion under high-shear conditions to reveal this role for pEtN cellulose which escaped detection using conventional tissue culture adhesion assays. Together with complementary biochemical experiments, the results support a model wherein cellulose serves a mortar-like function to promote curli association with and around the bacterial cell surface, resulting in increased bacterial adhesion strength at the bladder cell surface.
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Affiliation(s)
- Emily C Hollenbeck
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305
| | | | - Chew Chai
- Department of Bioengineering, Stanford University, Stanford, CA 94305
| | | | - Gerald G Fuller
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305;
| | - Lynette Cegelski
- Department of Chemistry, Stanford University, Stanford, CA 94305;
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Nhu NTK, Phan MD, Peters KM, Lo AW, Forde BM, Min Chong T, Yin WF, Chan KG, Chromek M, Brauner A, Chapman MR, Beatson SA, Schembri MA. Discovery of New Genes Involved in Curli Production by a Uropathogenic Escherichia coli Strain from the Highly Virulent O45:K1:H7 Lineage. mBio 2018; 9:e01462-18. [PMID: 30131362 PMCID: PMC6106082 DOI: 10.1128/mbio.01462-18] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 07/10/2018] [Indexed: 11/20/2022] Open
Abstract
Curli are bacterial surface-associated amyloid fibers that bind to the dye Congo red (CR) and facilitate uropathogenic Escherichia coli (UPEC) biofilm formation and protection against host innate defenses. Here we sequenced the genome of the curli-producing UPEC pyelonephritis strain MS7163 and showed it belongs to the highly virulent O45:K1:H7 neonatal meningitis-associated clone. MS7163 produced curli at human physiological temperature, and this correlated with biofilm growth, resistance of sessile cells to the human cationic peptide cathelicidin, and enhanced colonization of the mouse bladder. We devised a forward genetic screen using CR staining as a proxy for curli production and identified 41 genes that were required for optimal CR binding, of which 19 genes were essential for curli synthesis. Ten of these genes were novel or poorly characterized with respect to curli synthesis and included genes involved in purine de novo biosynthesis, a regulator that controls the Rcs phosphorelay system, and a novel repressor of curli production (referred to as rcpA). The involvement of these genes in curli production was confirmed by the construction of defined mutants and their complementation. The mutants did not express the curli major subunit CsgA and failed to produce curli based on CR binding. Mutation of purF (the first gene in the purine biosynthesis pathway) and rcpA also led to attenuated colonization of the mouse bladder. Overall, this work has provided new insight into the regulation of curli and the role of these amyloid fibers in UPEC biofilm formation and pathogenesis.IMPORTANCE Uropathogenic Escherichia coli (UPEC) strains are the most common cause of urinary tract infection, a disease increasingly associated with escalating antibiotic resistance. UPEC strains possess multiple surface-associated factors that enable their colonization of the urinary tract, including fimbriae, curli, and autotransporters. Curli are extracellular amyloid fibers that enhance UPEC virulence and promote biofilm formation. Here we examined the function and regulation of curli in a UPEC pyelonephritis strain belonging to the highly virulent O45:K1:H7 neonatal meningitis-associated clone. Curli expression at human physiological temperature led to increased biofilm formation, resistance of sessile cells to the human cationic peptide LL-37, and enhanced bladder colonization. Using a comprehensive genetic screen, we identified multiple genes involved in curli production, including several that were novel or poorly characterized with respect to curli synthesis. In total, this study demonstrates an important role for curli as a UPEC virulence factor that promotes biofilm formation, resistance, and pathogenesis.
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Affiliation(s)
- Nguyen Thi Khanh Nhu
- School of Chemistry and Molecular Biosciences, the University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, the University of Queensland, Brisbane, Queensland, Australia
- Australian Centre for Ecogenomics, the University of Queensland, Brisbane, Queensland, Australia
| | - Minh-Duy Phan
- School of Chemistry and Molecular Biosciences, the University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, the University of Queensland, Brisbane, Queensland, Australia
| | - Kate M Peters
- School of Chemistry and Molecular Biosciences, the University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, the University of Queensland, Brisbane, Queensland, Australia
| | - Alvin W Lo
- School of Chemistry and Molecular Biosciences, the University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, the University of Queensland, Brisbane, Queensland, Australia
| | - Brian M Forde
- School of Chemistry and Molecular Biosciences, the University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, the University of Queensland, Brisbane, Queensland, Australia
- Australian Centre for Ecogenomics, the University of Queensland, Brisbane, Queensland, Australia
| | - Teik Min Chong
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Sciences, University of Malaya, Kuala Lumpur, Malaysia
| | - Wai-Fong Yin
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Sciences, University of Malaya, Kuala Lumpur, Malaysia
| | - Kok-Gan Chan
- Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Sciences, University of Malaya, Kuala Lumpur, Malaysia
- International Genome Centre, Jiangsu University, Zhenjiang, China
| | - Milan Chromek
- Department of Microbiology, Tumor and Cell Biology, Division of Clinical Microbiology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
- Department of Pediatrics, CLINTEC, Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden
| | - Annelie Brauner
- Department of Microbiology, Tumor and Cell Biology, Division of Clinical Microbiology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Matthew R Chapman
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Scott A Beatson
- School of Chemistry and Molecular Biosciences, the University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, the University of Queensland, Brisbane, Queensland, Australia
- Australian Centre for Ecogenomics, the University of Queensland, Brisbane, Queensland, Australia
| | - Mark A Schembri
- School of Chemistry and Molecular Biosciences, the University of Queensland, Brisbane, Queensland, Australia
- Australian Infectious Diseases Research Centre, the University of Queensland, Brisbane, Queensland, Australia
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Madsen JS, Hylling O, Jacquiod S, Pécastaings S, Hansen LH, Riber L, Vestergaard G, Sørensen SJ. An intriguing relationship between the cyclic diguanylate signaling system and horizontal gene transfer. ISME JOURNAL 2018; 12:2330-2334. [PMID: 29899518 DOI: 10.1038/s41396-018-0183-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 03/11/2018] [Accepted: 03/20/2018] [Indexed: 11/09/2022]
Abstract
The second messenger cyclic diguanylate (c-di-GMP) is ubiquitously used by bacteria to modulate and shift between different phenotypes including motility, biofilm formation and virulence. Here we show that c-di-GMP-associated genes are widespread on plasmids and that enzymes that synthesize or degrade c-di-GMP are preferentially encoded on transmissible plasmids. Additionally, expression of enzymes that synthesize c-di-GMP was found to increase both biofilm formation and, interestingly, conjugative plasmid transfer rates.
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Affiliation(s)
- Jonas S Madsen
- Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100, Copenhagen, Denmark
| | - Ole Hylling
- Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100, Copenhagen, Denmark.,Department of Environment Sciences, Aarhus University, Frederiksborgvej 399, DK-4000, Roskilde, Denmark
| | - Samuel Jacquiod
- Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100, Copenhagen, Denmark
| | - Sophia Pécastaings
- Laboratoire de Génie Chimique UMR 5503, BioSym Department, Université Paul Sabatier, Université de Toulouse, 35 chemin des Maraîchers, 31062, Toulouse, France
| | - Lars H Hansen
- Department of Environment Sciences, Aarhus University, Frederiksborgvej 399, DK-4000, Roskilde, Denmark
| | - Leise Riber
- Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100, Copenhagen, Denmark
| | - Gisle Vestergaard
- Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100, Copenhagen, Denmark
| | - Søren J Sørensen
- Department of Biology, University of Copenhagen, Universitetsparken 15, DK-2100, Copenhagen, Denmark.
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30
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Experimental Detection and Visualization of the Extracellular Matrix in Macrocolony Biofilms. Methods Mol Biol 2018; 1657:133-145. [PMID: 28889291 DOI: 10.1007/978-1-4939-7240-1_11] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
By adopting elaborate three-dimensional morphologies that vary according to their extracellular matrix composition, macrocolony biofilms offer a unique opportunity to interrogate about the roles of specific matrix components in shaping biofilm architecture. Here, we describe two methods optimized for Escherichia coli that profit from morphology and the high level of structural organization of macrocolonies to gain insight into the production and assembly of amyloid curli and cellulose-the two major biofilm matrix elements of E. coli-in biofilms. The first method, the macrocolony morphology assay, is based on the ability of curli and cellulose-either alone or in combination-to generate specific morphological and Congo Red-staining patterns in E. coli macrocolonies, which can then be used as a direct visual readout for the production of these matrix components. The second method involves thin sectioning of macrocolonies, which along with in situ staining of amyloid curli and cellulose and microscopic imaging allows gaining fine details of the spatial arrangement of both matrix elements inside macrocolonies. Beyond their current use with E. coli and related curli and cellulose-producing Enterobacteriaceae, both the methods offer the potential to be adapted to other bacterial species.
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Affiliation(s)
- Michael Y Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA.
| | - Daria N Shalaeva
- School of Bioengineering and Bioinformatics, Moscow State University, Moscow 119992, Russia. .,School of Physics, University of Osnabrück, Osnabrück D-49069, Germany
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Thongsomboon W, Serra DO, Possling A, Hadjineophytou C, Hengge R, Cegelski L. Phosphoethanolamine cellulose: A naturally produced chemically modified cellulose. Science 2018; 359:334-338. [DOI: 10.1126/science.aao4096] [Citation(s) in RCA: 150] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 11/13/2017] [Indexed: 12/22/2022]
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Kampmeier S, Berger M, Mellmann A, Karch H, Berger P. The 2011 German Enterohemorrhagic Escherichia Coli O104:H4 Outbreak-The Danger Is Still Out There. Curr Top Microbiol Immunol 2018; 416:117-148. [PMID: 30062592 DOI: 10.1007/82_2018_107] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Enterohemorrhagic Escherichia coli (EHEC) are Shiga toxin (Stx) producing bacteria causing a disease characterized by bloody (or non-bloody) diarrhea, which might progress to hemolytic uremic syndrome (HUS). EHEC O104:H4 caused the largest ever recorded EHEC outbreak in Germany in 2011, which in addition showed the so far highest incidence rate of EHEC-related HUS worldwide. The aggressive outbreak strain carries an unusual combination of virulence traits characteristic to both EHEC-a chromosomally integrated Stx-encoding bacteriophage, and enteroaggregative Escherichia coli-pAA plasmid-encoded aggregative adherence fimbriae mediating its tight adhesion to epithelia cells. There are currently still open questions regarding the 2011 EHEC outbreak, e.g., with respect to the exact molecular mechanisms resulting in the hypervirulence of the strain, the natural reservoir of EHEC O104:H4, and suitable therapeutic strategies. Nevertheless, our knowledge on these issues has substantially expanded since 2011. Here, we present an overview of the epidemiological, clinical, microbiological, and molecular biological data available on the 2011 German EHEC O104:H4 outbreak.
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Affiliation(s)
| | - Michael Berger
- Institute of Hygiene, University of Münster, Münster, Germany
| | | | - Helge Karch
- Institute of Hygiene, University of Münster, Münster, Germany
| | - Petya Berger
- Institute of Hygiene, University of Münster, Münster, Germany.
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Hall CL, Lee VT. Cyclic-di-GMP regulation of virulence in bacterial pathogens. WILEY INTERDISCIPLINARY REVIEWS. RNA 2018; 9:10.1002/wrna.1454. [PMID: 28990312 PMCID: PMC5739959 DOI: 10.1002/wrna.1454] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 08/29/2017] [Accepted: 09/01/2017] [Indexed: 12/16/2022]
Abstract
Signaling pathways allow bacteria to adapt to changing environments. For pathogenic bacteria, signaling pathways allow for timely expression of virulence factors and the repression of antivirulence factors within the mammalian host. As the bacteria exit the mammalian host, signaling pathways enable the expression of factors promoting survival in the environment and/or nonmammalian hosts. One such signaling pathway uses the dinucleotide cyclic-di-GMP (c-di-GMP), and many bacterial genomes encode numerous proteins that are responsible for synthesizing and degrading c-di-GMP. Once made, c-di-GMP binds to individual protein and RNA receptors to allosterically alter the macromolecule function to drive phenotypic changes. Each bacterial genome encodes unique sets of genes for c-di-GMP signaling and virulence factors so the regulation by c-di-GMP is organism specific. Recent works have pointed to evidence that c-di-GMP regulates virulence in different bacterial pathogens of mammalian hosts. In this review, we discuss the criteria for determining the contribution of signaling nucleotides to pathogenesis using a well-characterized signaling nucleotide, cyclic AMP (cAMP), in Pseudomonas aeruginosa. Using these criteria, we review the roles of c-di-GMP in mediating virulence and highlight common themes that exist among eight diverse pathogens that cause different diseases through different routes of infection and transmission. WIREs RNA 2018, 9:e1454. doi: 10.1002/wrna.1454 This article is categorized under: RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
- Cherisse L Hall
- Department of Cell Biology and Molecular Genetics, University of Maryland at College Park, College Park, MD, USA
| | - Vincent T Lee
- Department of Cell Biology and Molecular Genetics, University of Maryland at College Park, College Park, MD, USA
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35
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Köckerling E, Karrasch L, Schweitzer A, Razum O, Krause G. Public Health Research Resulting from One of the World's Largest Outbreaks Caused by Entero-Hemorrhagic Escherichia coli in Germany 2011: A Review. Front Public Health 2017; 5:332. [PMID: 29312915 PMCID: PMC5732330 DOI: 10.3389/fpubh.2017.00332] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 11/23/2017] [Indexed: 02/04/2023] Open
Abstract
In 2011, Germany experienced one of the largest outbreaks of entero-hemorrhagic Escherichia coli (EHEC) ever reported. Four years thereafter, we systematically searched for scientific publications in PubMed and MEDPILOT relating to this outbreak in order to assess the pattern of respective research activities and to assess the main findings and recommendations in the field of public health. Following PRISMA guidelines, we selected 133 publications, half of which were published within 17 months after outbreak onset. Clinical medicine was covered by 71, microbiology by 60, epidemiology by 46, outbreak reporting by 11, and food safety by 9 papers. Those on the last three topics drew conclusions on methods in surveillance, diagnosis, and outbreak investigation, on resources in public health, as well as on inter-agency collaboration, and public communication. Although the outbreak primarily affected Germany, most publications were conducted by multinational cooperations. Our findings document how soon and in which fields research was conducted with respect to this outbreak.
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Affiliation(s)
- Elena Köckerling
- Department of Epidemiology and International Public Health, Bielefeld University, Bielefeld, Germany.,Department Münster, Institute for Rehabilitation Research IfR, Münster, Germany
| | - Laura Karrasch
- Department of Epidemiology and International Public Health, Bielefeld University, Bielefeld, Germany
| | - Aparna Schweitzer
- Department of Epidemiology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Oliver Razum
- Department of Epidemiology and International Public Health, Bielefeld University, Bielefeld, Germany
| | - Gérard Krause
- Department of Epidemiology, Helmholtz Centre for Infection Research, Braunschweig, Germany.,Hannover Medical School, Hannover, Germany
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Wen Y, Ouyang Z, Devreese B, He W, Shao Y, Lu W, Zheng F. Crystal structure of master biofilm regulator CsgD regulatory domain reveals an atypical receiver domain. Protein Sci 2017; 26:2073-2082. [PMID: 28758290 PMCID: PMC5606546 DOI: 10.1002/pro.3245] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/13/2017] [Accepted: 07/13/2017] [Indexed: 11/11/2022]
Abstract
The master regulator CsgD switches planktonic growth to biofilm formation by activating synthesis of curli fimbriae and cellulose in Enterobacteriaceae. CsgD was classified to be the LuxR response regulatory family, while its cognate sensor histidine kinase has not been identified yet. CsgD consists of a C-terminal DNA binding domain and an N-terminal regulatory domain that provokes the upstream signal transduction to further modulate its function. We provide the crystal structure of Salmonella Typhimurium CsgD regulatory domain, which reveals an atypical β5α5 response regulatory receiver domain folding with the α2 helix representing as a disorder loop compared to the LuxR/FixJ canonical response regulator, and the structure indicated a noteworthy α5 helix similar to the non-canonical master regulator VpsT receiver domain α6. CsgD regulatory domain assembles with two dimerization interfaces mainly through α1 and α5, which has shown similarity to the c-di-GMP independent and stabilized dimerization interface of VpsT from Vibrio cholerae respectively. The potential phosphorylation site D59 is directly involved in the interaction of interfaces I and mutagenesis studies indicated that both dimerization interfaces could be crucial for CsgD activity. The structure reveals important molecular details for the dimerization assembly of CsgD and will shed new insight into its regulation mechanism.
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Affiliation(s)
- Yurong Wen
- Center for Translational MedicineThe Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong UniversityXi'anChina
| | - Zhenlin Ouyang
- Center for Translational MedicineThe Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong UniversityXi'anChina
| | - Bart Devreese
- Unit for Biological Mass Spectrometry and ProteomicsLaboratory for Protein Biochemistry and Biomolecular Engineering (L‐ProBE), Ghent UniversityGhentBelgium
| | - Wangxiao He
- Center for Translational MedicineThe Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong UniversityXi'anChina
| | - Yongping Shao
- Center for Translational MedicineThe Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong UniversityXi'anChina
| | - Wuyuan Lu
- Center for Translational MedicineThe Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong UniversityXi'anChina
| | - Fang Zheng
- Department of Biochemistry and Molecular BiologyThe Key Laboratory of Environment and Genes Related to Disease of Ministry of Education, Health Science Center, Xi'an Jiaotong UniversityXi'anChina
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Cimdins A, Simm R, Li F, Lüthje P, Thorell K, Sjöling Å, Brauner A, Römling U. Alterations of c-di-GMP turnover proteins modulate semi-constitutive rdar biofilm formation in commensal and uropathogenic Escherichia coli. Microbiologyopen 2017; 6. [PMID: 28913868 PMCID: PMC5635171 DOI: 10.1002/mbo3.508] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 05/25/2017] [Indexed: 01/25/2023] Open
Abstract
Agar plate‐based biofilm of enterobacteria like Escherichia coli is characterized by expression of the extracellular matrix components amyloid curli and cellulose exopolysaccharide, which can be visually enhanced upon addition of the dye Congo Red, resulting in a red, dry, and rough (rdar) colony morphology. Expression of the rdar morphotype depends on the transcriptional regulator CsgD and occurs predominantly at ambient temperature in model strains. In contrast, commensal and pathogenic isolates frequently express the csgD‐dependent rdar morphotype semi‐constitutively, also at human host body temperature. To unravel the molecular basis of temperature‐independent rdar morphotype expression, biofilm components and c‐di‐GMP turnover proteins of seven commensal and uropathogenic E. coli isolates were analyzed. A diversity within the c‐di‐GMP signaling network was uncovered which suggests alteration of activity of the trigger phosphodiesterase YciR to contribute to (up)regulation of csgD expression and consequently semi‐constitutive rdar morphotype development.
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Affiliation(s)
- Annika Cimdins
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Roger Simm
- Norwegian Veterinary Institute, Oslo, Norway
| | - Fengyang Li
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Petra Lüthje
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden.,Division of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
| | - Kaisa Thorell
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Åsa Sjöling
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Annelie Brauner
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden.,Division of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
| | - Ute Römling
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden
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MacKenzie KD, Palmer MB, Köster WL, White AP. Examining the Link between Biofilm Formation and the Ability of Pathogenic Salmonella Strains to Colonize Multiple Host Species. Front Vet Sci 2017; 4:138. [PMID: 29159172 PMCID: PMC5581909 DOI: 10.3389/fvets.2017.00138] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Accepted: 08/09/2017] [Indexed: 12/11/2022] Open
Abstract
Salmonella are important pathogens worldwide and a predominant number of human infections are zoonotic in nature. The ability of strains to form biofilms, which is a multicellular behavior characterized by the aggregation of cells, is predicted to be a conserved strategy for increased persistence and survival. It may also contribute to the increasing number of infections caused by ingestion of contaminated fruits and vegetables. There is a correlation between biofilm formation and the ability of strains to colonize and replicate within the intestines of multiple host species. These strains predominantly cause localized gastroenteritis infections in humans. In contrast, there are salmonellae that cause systemic, disseminated infections in a select few host species; these “invasive” strains have a narrowed host range, and most are unable to form biofilms. This includes host-restricted Salmonella serovar Typhi, which are only able to infect humans, and atypical gastroenteritis strains associated with the opportunistic infection of immunocompromised patients. From the perspective of transmission, biofilm formation is advantageous for ensuring pathogen survival in the environment. However, from an infection point of view, biofilm formation may be an anti-virulence trait. We do not know if the capacity to form biofilms prevents a strain from accessing the systemic compartments within the host or if loss of the biofilm phenotype reflects a change in a strain’s interaction with the host. In this review, we examine the connections between biofilm formation, Salmonella disease states, degrees of host adaptation, and how this might relate to different transmission patterns. A better understanding of the dynamic lifecycle of Salmonella will allow us to reduce the burden of livestock and human infections caused by these important pathogens.
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Affiliation(s)
- Keith D MacKenzie
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, SK, Canada.,Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Melissa B Palmer
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, SK, Canada.,Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Wolfgang L Köster
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, SK, Canada.,Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Aaron P White
- Vaccine and Infectious Disease Organization-International Vaccine Centre, Saskatoon, SK, Canada.,Department of Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
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Biofilm Formation Potential of Heat-Resistant Escherichia coli Dairy Isolates and the Complete Genome of Multidrug-Resistant, Heat-Resistant Strain FAM21845. Appl Environ Microbiol 2017; 83:AEM.00628-17. [PMID: 28550056 PMCID: PMC5514686 DOI: 10.1128/aem.00628-17] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 05/18/2017] [Indexed: 02/07/2023] Open
Abstract
We tested the biofilm formation potential of 30 heat-resistant and 6 heat-sensitive Escherichia coli dairy isolates. Production of curli and cellulose, static biofilm formation on polystyrene (PS) and stainless steel surfaces, biofilm formation under dynamic conditions (Bioflux), and initial adhesion rates (IAR) were evaluated. Biofilm formation varied greatly between strains, media, and assays. Our results highlight the importance of the experimental setup in determining biofilm formation under conditions of interest, as correlation between different assays was often not a given. The heat-resistant, multidrug-resistant (MDR) strain FAM21845 showed the strongest biofilm formation on PS and the highest IAR and was the only strain that formed significant biofilms on stainless steel under conditions relevant to the dairy industry, and it was therefore fully sequenced. Its chromosome is 4.9 Mb long, and it harbors a total of five plasmids (147.2, 54.2, 5.8, 2.5, and 1.9 kb). The strain carries a broad range of genes relevant to antimicrobial resistance and biofilm formation, including some on its two large conjugative plasmids, as demonstrated in plate mating assays.IMPORTANCE In biofilms, cells are embedded in an extracellular matrix that protects them from stresses, such as UV radiation, osmotic shock, desiccation, antibiotics, and predation. Biofilm formation is a major bacterial persistence factor of great concern in the clinic and the food industry. Many tested strains formed strong biofilms, and especially strains such as the heat-resistant, MDR strain FAM21845 may pose a serious issue for food production. Strong biofilm formation combined with diverse resistances (some encoded on conjugative plasmids) may allow for increased persistence, coselection, and possible transfer of these resistance factors. Horizontal gene transfer may conceivably occur in the food production setting or the gastrointestinal tract after consumption.
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Rossi E, Cimdins A, Lüthje P, Brauner A, Sjöling Å, Landini P, Römling U. "It's a gut feeling" - Escherichia coli biofilm formation in the gastrointestinal tract environment. Crit Rev Microbiol 2017; 44:1-30. [PMID: 28485690 DOI: 10.1080/1040841x.2017.1303660] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Escherichia coli can commonly be found, either as a commensal, probiotic or a pathogen, in the human gastrointestinal (GI) tract. Biofilm formation and its regulation is surprisingly variable, although distinct regulatory pattern of red, dry and rough (rdar) biofilm formation arise in certain pathovars and even clones. In the GI tract, environmental conditions, signals from the host and from commensal bacteria contribute to shape E. coli biofilm formation within the multi-faceted multicellular communities in a complex and integrated fashion. Although some major regulatory networks, adhesion factors and extracellular matrix components constituting E. coli biofilms have been recognized, these processes have mainly been characterized in vitro and in the context of interaction of E. coli strains with intestinal epithelial cells. However, direct observation of E. coli cells in situ, and the vast number of genes encoding surface appendages on the core or accessory genome of E. coli suggests the complexity of the biofilm process to be far from being fully understood. In this review, we summarize biofilm formation mechanisms of commensal, probiotic and pathogenic E. coli in the context of the gastrointestinal tract.
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Affiliation(s)
- Elio Rossi
- a Department of Biosciences , Università degli Studi di Milano , Milan , Italy.,b Novo Nordisk Center for Biosustainabiliy , Technical University of Denmark , Kgs. Lyngby , Denmark
| | - Annika Cimdins
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden.,d Institute of Hygiene, University of Münster , Münster , Germany
| | - Petra Lüthje
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden.,e Division of Clinical Microbiology, Department of Laboratory Medicine , Karolinska Institutet and Karolinska University Hospital Huddinge , Stockholm , Sweden
| | - Annelie Brauner
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden
| | - Åsa Sjöling
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden
| | - Paolo Landini
- a Department of Biosciences , Università degli Studi di Milano , Milan , Italy
| | - Ute Römling
- c Department of Microbiology, Tumor and Cell Biology (MTC) , Karolinska Institutet , Stockholm , Sweden
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Abstract
Cyclic dinucleotides (CDNs) are highly versatile signalling molecules that control various important biological processes in bacteria. The best-studied example is cyclic di-GMP (c-di-GMP). Known since the late 1980s, it is now recognized as a near-ubiquitous second messenger that coordinates diverse aspects of bacterial growth and behaviour, including motility, virulence, biofilm formation and cell cycle progression. In this Review, we discuss important new insights that have been gained into the molecular principles of c-di-GMP synthesis and degradation, which are mediated by diguanylate cyclases and c-di-GMP-specific phosphodiesterases, respectively, and the cellular functions that are exerted by c-di-GMP-binding effectors and their diverse targets. Finally, we provide a short overview of the signalling versatility of other CDNs, including c-di-AMP and cGMP-AMP (cGAMP).
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Kim YG, Lee JH, Gwon G, Kim SI, Park JG, Lee J. Essential Oils and Eugenols Inhibit Biofilm Formation and the Virulence of Escherichia coli O157:H7. Sci Rep 2016; 6:36377. [PMID: 27808174 PMCID: PMC5093407 DOI: 10.1038/srep36377] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 10/14/2016] [Indexed: 02/06/2023] Open
Abstract
Enterohemorrhagic Escherichia coli O157:H7 (EHEC) has caused foodborne outbreaks worldwide and the bacterium forms antimicrobial-tolerant biofilms. We investigated the abilities of various plant essential oils and their components to inhibit biofilm formation by EHEC. Bay, clove, pimento berry oils and their major common constituent eugenol at 0.005% (v/v) were found to markedly inhibit EHEC biofilm formation without affecting planktonic cell growth. In addition, three other eugenol derivatives isoeugenol, 2-methoxy-4-propylphenol, and 4-ethylguaiacol had antibiofilm activity, indicating that the C-1 hydroxyl unit, the C-2 methoxy unit, and C-4 alkyl or alkane chain on the benzene ring of eugenol play important roles in antibiofilm activity. Interestingly, these essential oils and eugenol did not inhibit biofilm formation by three laboratory E. coli K-12 strains that reduced curli fimbriae production. Transcriptional analysis showed that eugenol down-regulated 17 of 28 genes analysed, including curli genes (csgABDFG), type I fimbriae genes (fimCDH) and ler-controlled toxin genes (espD, escJ, escR, and tir), which are required for biofilm formation and the attachment and effacement phenotype. In addition, biocompatible poly(lactic-co-glycolic acid) coatings containing clove oil or eugenol exhibited efficient biofilm inhibition on solid surfaces. In a Caenorhabditis elegans nematode model, clove oil and eugenol attenuated the virulence of EHEC.
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Affiliation(s)
- Yong-Guy Kim
- School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea
| | - Jin-Hyung Lee
- School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea
| | - Giyeon Gwon
- School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea
| | - Soon-Il Kim
- Nareso Research Center, Seoho-ro 89, Suwon 16614, Republic of Korea
| | - Jae Gyu Park
- Pohang Center for Evaluation of Biomaterials, Pohang Technopark Foundation, Pohang 37668, Republic of Korea
| | - Jintae Lee
- School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea
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Sloup RE, Cieza RJ, Needle DB, Abramovitch RB, Torres AG, Waters CM. Polysorbates prevent biofilm formation and pathogenesis of Escherichia coli O104:H4. BIOFOULING 2016; 32:1131-1140. [PMID: 27667095 PMCID: PMC5176131 DOI: 10.1080/08927014.2016.1230849] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 08/25/2016] [Indexed: 06/06/2023]
Abstract
Escherichia coli biotype O104:H4 recently caused the deadliest E. coli outbreak ever reported. Based on prior results, it was hypothesized that compounds inhibiting biofilm formation by O104:H4 would reduce its pathogenesis. The nonionic surfactants polysorbate 80 (PS80) and polysorbate 20 (PS20) were found to reduce biofilms by ≥ 90% at submicromolar concentrations and elicited nearly complete dispersal of preformed biofilms. PS80 did not significantly impact in vivo colonization in a mouse infection model; however, mice treated with PS80 exhibited almost no intestinal inflammation or tissue damage while untreated mice exhibited robust pathology. As PS20 and PS80 are classified as 'Generally Recognized as Safe' (GRAS) compounds by the Food and Drug Administration (FDA), these compounds have clinical potential to treat future O104:H4 outbreaks.
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Affiliation(s)
- Rudolph E. Sloup
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, 48824
| | - Roberto J. Cieza
- Department of Microbiology and Immunology, and Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, Texas, 77555
| | - David B. Needle
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, 48824
| | - Robert B. Abramovitch
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, 48824
| | - Alfredo G. Torres
- Department of Microbiology and Immunology, and Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, Texas, 77555
| | - Christopher M. Waters
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, 48824
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, Michigan, 48824
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44
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Orr MW, Galperin MY, Lee VT. Sustained sensing as an emerging principle in second messenger signaling systems. Curr Opin Microbiol 2016; 34:119-126. [PMID: 27700990 DOI: 10.1016/j.mib.2016.08.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 08/25/2016] [Accepted: 08/31/2016] [Indexed: 11/18/2022]
Abstract
Bacteria utilize a diverse set of nucleotide second messengers to regulate cellular responses by binding macromolecular receptors (RNAs and proteins). Recent studies on cyclic di-GMP (c-di-GMP) have shown that this signaling molecule binds multiple receptors to regulate different steps in the same biological process. We propose this property of the same molecule regulating multiple steps in the same process is biologically meaningful and have termed this phenomenon 'sustained sensing'. Here, we discuss the recent findings that support the concept of sustained sensing of c-di-GMP levels and provide additional examples that support the utilization of sustained sensing by other second messengers. Sustained sensing may be widespread in bacteria and provides an additional level of complexity in prokaryotic signal transduction networks.
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Affiliation(s)
- Mona W Orr
- Department of Cell Biology and Molecular Genetics, University of Maryland at College Park, College Park, MD, USA; Maryland Pathogen Research Institute, University of Maryland at College Park, College Park, MD, USA
| | - Michael Y Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Vincent T Lee
- Department of Cell Biology and Molecular Genetics, University of Maryland at College Park, College Park, MD, USA; Maryland Pathogen Research Institute, University of Maryland at College Park, College Park, MD, USA.
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45
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Pécastaings S, Allombert J, Lajoie B, Doublet P, Roques C, Vianney A. New insights into Legionella pneumophila biofilm regulation by c-di-GMP signaling. BIOFOULING 2016; 32:935-948. [PMID: 27494738 DOI: 10.1080/08927014.2016.1212988] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 07/07/2016] [Indexed: 06/06/2023]
Abstract
The waterborne pathogen Legionella pneumophila grows as a biofilm, freely or inside amoebae. Cyclic-di-GMP (c-di-GMP), a bacterial second messenger frequently implicated in biofilm formation, is synthesized and degraded by diguanylate cyclases (DGCs) and phosphodiesterases (PDEs), respectively. To characterize the c-di-GMP-metabolizing enzymes involved in L. pneumophila biofilm regulation, the consequences on biofilm formation and the c-di-GMP concentration of each corresponding gene inactivation were assessed in the Lens strain. The results showed that one DGC and two PDEs enhance different aspects of biofilm formation, while two proteins with dual activity (DGC/PDE) inhibit biofilm growth. Surprisingly, only two mutants exhibited a change in global c-di-GMP concentration. This study highlights that specific c-di-GMP pathways control L. pneumophila biofilm formation, most likely via temporary and/or local modulation of c-di-GMP concentration. Furthermore, Lpl1054 DGC is required to enable the formation a dense biofilm in response to nitric oxide, a signal for biofilm dispersion in many other species.
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Affiliation(s)
- Sophie Pécastaings
- a Laboratoire de Génie chimique UMR 5503 , UPS, Université de Toulouse , Toulouse , France
| | - Julie Allombert
- b CIRI, International Center for Infectiology Research , Legionella Pathogenesis Group, Université de Lyon , Lyon , France
- c Inserm , Lyon , France
- d Ecole Normale Supérieure de Lyon , Lyon , France
- e Université Lyon 1, CIRI, International Center for Infectiology Research , Lyon , France
- f CNRS , Lyon , France
| | - Barbora Lajoie
- a Laboratoire de Génie chimique UMR 5503 , UPS, Université de Toulouse , Toulouse , France
| | - Patricia Doublet
- b CIRI, International Center for Infectiology Research , Legionella Pathogenesis Group, Université de Lyon , Lyon , France
- c Inserm , Lyon , France
- d Ecole Normale Supérieure de Lyon , Lyon , France
- e Université Lyon 1, CIRI, International Center for Infectiology Research , Lyon , France
- f CNRS , Lyon , France
| | - Christine Roques
- a Laboratoire de Génie chimique UMR 5503 , UPS, Université de Toulouse , Toulouse , France
| | - Anne Vianney
- b CIRI, International Center for Infectiology Research , Legionella Pathogenesis Group, Université de Lyon , Lyon , France
- c Inserm , Lyon , France
- d Ecole Normale Supérieure de Lyon , Lyon , France
- e Université Lyon 1, CIRI, International Center for Infectiology Research , Lyon , France
- f CNRS , Lyon , France
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46
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Serra DO, Mika F, Richter AM, Hengge R. The green tea polyphenol EGCG inhibits E. coli biofilm formation by impairing amyloid curli fibre assembly and downregulating the biofilm regulator CsgD via the σ(E) -dependent sRNA RybB. Mol Microbiol 2016; 101:136-51. [PMID: 26992034 DOI: 10.1111/mmi.13379] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/16/2016] [Indexed: 01/17/2023]
Abstract
In bacterial biofilms, which are often involved in chronic infections, cells are surrounded by a self-produced extracellular matrix that contains amyloid fibres, exopolysaccharides and other biopolymers. The matrix contributes to the pronounced resistance of biofilms against antibiotics and host immune systems. Being highly inflammatory, matrix amyloids such as curli fibres of Escherichia coli can also play a role in pathogenicity. Using macrocolony biofilms of commensal and pathogenic E. coli as a model system, we demonstrate here that the green tea polyphenol epigallocatachin gallate (EGCG) is a potent antibiofilm agent. EGCG virtually eliminates the biofilm matrix by directly interfering with the assembly of curli subunits into amyloid fibres, and by triggering the σ(E) cell envelope stress response and thereby reducing the expression of CsgD - a crucial activator of curli and cellulose biosynthesis - due to csgD mRNA targeting by the σ(E) -dependent sRNA RybB. These findings highlight EGCG as a potential adjuvant for antibiotic therapy of biofilm-associated infections. Moreover, EGCG may support therapies against pathogenic E. coli that produce inflammatory curli fibres along with Shigatoxin.
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Affiliation(s)
- Diego O Serra
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, 10115, Berlin, Germany
| | - Franziska Mika
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, 10115, Berlin, Germany
| | - Anja M Richter
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, 10115, Berlin, Germany
| | - Regine Hengge
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, 10115, Berlin, Germany
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47
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Schaufler K, Semmler T, Pickard DJ, de Toro M, de la Cruz F, Wieler LH, Ewers C, Guenther S. Carriage of Extended-Spectrum Beta-Lactamase-Plasmids Does Not Reduce Fitness but Enhances Virulence in Some Strains of Pandemic E. coli Lineages. Front Microbiol 2016; 7:336. [PMID: 27014251 PMCID: PMC4794485 DOI: 10.3389/fmicb.2016.00336] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 03/03/2016] [Indexed: 11/20/2022] Open
Abstract
Pathogenic ESBL-producing E. coli lineages occur frequently worldwide, not only in a human health context but in animals and the environment, also in settings with low antimicrobial pressures. This study investigated the fitness costs of ESBL-plasmids and their influence on chromosomally encoded features associated with virulence, such as those involved in the planktonic and sessile behaviors of ST131 and ST648 E. coli. ESBL-plasmid-carrying wild-type E. coli strains, their corresponding ESBL-plasmid-“cured” variants (PCV), and complementary ESBL-carrying transformants were comparatively analyzed using growth curves, Omnilog® phenotype microarray (PM) assays, macrocolony and biofilm formation, swimming motility, and RNA sequence analysis. Growth curves and PM results pointed toward similar growth and metabolic behaviors among the strains. Phenotypic differences in some strains were detected, including enhanced curli fimbriae and/or cellulose production as well as a reduced swimming capacity of some ESBL-carrying strains, as compared to their respective PCVs. RNA sequencing mostly confirmed the phenotypic results, suggesting that the chromosomally encoded csgD pathway is a key factor involved. These results contradict the hypothesis that ESBL-plasmid-carriage leads to a fitness loss in ESBL-carrying strains. Instead, the results indicate an influence of some ESBL-plasmids on chromosomally encoded features associated with virulence in some E. coli strains. In conclusion, apart from antibiotic resistance selective advantages, ESBL-plasmid-carriage may also lead to enhanced virulence or adaption to specific habitats in some strains of pandemic ESBL-producing E. coli lineages.
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Affiliation(s)
- Katharina Schaufler
- Veterinary Faculty, Institute of Microbiology and Epizootics, Freie Universität Berlin Berlin, Germany
| | - Torsten Semmler
- Veterinary Faculty, Institute of Microbiology and Epizootics, Freie Universität BerlinBerlin, Germany; Robert Koch InstituteBerlin, Germany
| | | | - María de Toro
- Departamento de Biología Molecular, Instituto de Biomedicina y Biotecnología de Cantabria (UC-SODERCAN-CSIC), Universidad de Cantabria Santander, Spain
| | - Fernando de la Cruz
- Departamento de Biología Molecular, Instituto de Biomedicina y Biotecnología de Cantabria (UC-SODERCAN-CSIC), Universidad de Cantabria Santander, Spain
| | - Lothar H Wieler
- Veterinary Faculty, Institute of Microbiology and Epizootics, Freie Universität BerlinBerlin, Germany; Robert Koch InstituteBerlin, Germany
| | - Christa Ewers
- Veterinary Faculty, Institute of Hygiene and Infectious Diseases of Animals, Justus-Liebig-Universität Giessen Giessen, Germany
| | - Sebastian Guenther
- Veterinary Faculty, Institute of Microbiology and Epizootics, Freie Universität Berlin Berlin, Germany
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48
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Augimeri RV, Varley AJ, Strap JL. Establishing a Role for Bacterial Cellulose in Environmental Interactions: Lessons Learned from Diverse Biofilm-Producing Proteobacteria. Front Microbiol 2015; 6:1282. [PMID: 26635751 PMCID: PMC4646962 DOI: 10.3389/fmicb.2015.01282] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 10/31/2015] [Indexed: 01/21/2023] Open
Abstract
Bacterial cellulose (BC) serves as a molecular glue to facilitate intra- and inter-domain interactions in nature. Biosynthesis of BC-containing biofilms occurs in a variety of Proteobacteria that inhabit diverse ecological niches. The enzymatic and regulatory systems responsible for the polymerization, exportation, and regulation of BC are equally as diverse. Though the magnitude and environmental consequences of BC production are species-specific, the common role of BC-containing biofilms is to establish close contact with a preferred host to facilitate efficient host-bacteria interactions. Universally, BC aids in attachment, adherence, and subsequent colonization of a substrate. Bi-directional interactions influence host physiology, bacterial physiology, and regulation of BC biosynthesis, primarily through modulation of intracellular bis-(3'→5')-cyclic diguanylate (c-di-GMP) levels. Depending on the circumstance, BC producers exhibit a pathogenic or symbiotic relationship with plant, animal, or fungal hosts. Rhizobiaceae species colonize plant roots, Pseudomonadaceae inhabit the phyllosphere, Acetobacteriaceae associate with sugar-loving insects and inhabit the carposphere, Enterobacteriaceae use fresh produce as vehicles to infect animal hosts, and Vibrionaceae, particularly Aliivibrio fischeri, colonize the light organ of squid. This review will highlight the diversity of the biosynthesis and regulation of BC in nature by discussing various examples of Proteobacteria that use BC-containing biofilms to facilitate host-bacteria interactions. Through discussion of current data we will establish new directions for the elucidation of BC biosynthesis, its regulation and its ecophysiological roles.
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Affiliation(s)
| | | | - Janice L. Strap
- Molecular Microbial Biochemistry Laboratory, Faculty of Science, University of Ontario Institute of TechnologyOshawa, ON, Canada
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49
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Serra DO, Klauck G, Hengge R. Vertical stratification of matrix production is essential for physical integrity and architecture of macrocolony biofilms of Escherichia coli. Environ Microbiol 2015; 17:5073-88. [PMID: 26234179 PMCID: PMC5014196 DOI: 10.1111/1462-2920.12991] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 07/15/2015] [Indexed: 12/22/2022]
Abstract
Bacterial macrocolony biofilms grow into intricate three-dimensional structures that depend on self-produced extracellular polymers conferring protection, cohesion and elasticity to the biofilm. In Escherichia coli, synthesis of this matrix - consisting of amyloid curli fibres and cellulose - requires CsgD, a transcription factor regulated by the stationary phase sigma factor RpoS, and occurs in the nutrient-deprived cells of the upper layer of macrocolonies. Is this asymmetric matrix distribution functionally important or is it just a fortuitous by-product of an unavoidable nutrient gradient? In order to address this question, the RpoS-dependent csgD promoter was replaced by a vegetative promoter. This re-wiring of csgD led to CsgD and matrix production in both strata of macrocolonies, with the lower layer transforming into a rigid 'base plate' of growing yet curli-connected cells. As a result, the two strata broke apart followed by desiccation and exfoliation of the top layer. By contrast, matrix-free cells at the bottom of wild-type macrocolonies maintain colony contact with the humid agar support by flexibly filling the space that opens up under buckling areas of the macrocolony. Precisely regulated stratification in matrix-free and matrix-producing cell layers is thus essential for the physical integrity and architecture of E. coli macrocolony biofilms.
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Affiliation(s)
- Diego O Serra
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Berlin, 10115, Germany
| | - Gisela Klauck
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Berlin, 10115, Germany
| | - Regine Hengge
- Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Berlin, 10115, Germany
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Genome-Based Comparison of Cyclic Di-GMP Signaling in Pathogenic and Commensal Escherichia coli Strains. J Bacteriol 2015; 198:111-26. [PMID: 26303830 DOI: 10.1128/jb.00520-15] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 08/21/2015] [Indexed: 01/22/2023] Open
Abstract
UNLABELLED The ubiquitous bacterial second messenger cyclic di-GMP (c-di-GMP) has recently become prominent as a trigger for biofilm formation in many bacteria. It is generated by diguanylate cyclases (DGCs; with GGDEF domains) and degraded by specific phosphodiesterases (PDEs; containing either EAL or HD-GYP domains). Most bacterial species contain multiples of these proteins with some having specific functions that are based on direct molecular interactions in addition to their enzymatic activities. Escherichia coli K-12 laboratory strains feature 29 genes encoding GGDEF and/or EAL domains, resulting in a set of 12 DGCs, 13 PDEs, and four enzymatically inactive "degenerate" proteins that act by direct macromolecular interactions. We present here a comparative analysis of GGDEF/EAL domain-encoding genes in 61 genomes of pathogenic, commensal, and probiotic E. coli strains (including enteric pathogens such as enteroaggregative, enterohemorrhagic, enteropathogenic, enterotoxigenic, and adherent and invasive Escherichia coli and the 2011 German outbreak O104:H4 strain, as well as extraintestinal pathogenic E. coli, such as uropathogenic and meningitis-associated E. coli). We describe additional genes for two membrane-associated DGCs (DgcX and DgcY) and four PDEs (the membrane-associated PdeT, as well as the EAL domain-only proteins PdeW, PdeX, and PdeY), thus showing the pangenome of E. coli to contain at least 35 GGDEF/EAL domain proteins. A core set of only eight proteins is absolutely conserved in all 61 strains: DgcC (YaiC), DgcI (YliF), PdeB (YlaB), PdeH (YhjH), PdeK (YhjK), PdeN (Rtn), and the degenerate proteins CsrD and CdgI (YeaI). In all other GGDEF/EAL domain genes, diverse point and frameshift mutations, as well as small or large deletions, were discovered in various strains. IMPORTANCE Our analysis reveals interesting trends in pathogenic Escherichia coli that could reflect different host cell adherence mechanisms. These may either benefit from or be counteracted by the c-di-GMP-stimulated production of amyloid curli fibers and cellulose. Thus, EAEC, which adhere in a "stacked brick" biofilm mode, have a potential for high c-di-GMP accumulation due to DgcX, a strongly expressed additional DGC. In contrast, EHEC and UPEC, which use alternative adherence mechanisms, tend to have extra PDEs, suggesting that low cellular c-di-GMP levels are crucial for these strains under specific conditions. Overall, our study also indicates that GGDEF/EAL domain proteins evolve rapidly and thereby contribute to adaptation to host-specific and environmental niches of various types of E. coli.
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