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Zhang H, Zhai Y, Chen K, Shi H. Adhesion of Escherichia coli O157:H7 during sublethal injury and resuscitation: Importance of pili and surface properties. Food Microbiol 2023; 115:104329. [PMID: 37567635 DOI: 10.1016/j.fm.2023.104329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 06/19/2023] [Accepted: 06/19/2023] [Indexed: 08/13/2023]
Abstract
Escherichia coli O157:H7 can recover from sublethally injured (SI) state, which causes threat of foodborne illness. Adhesion plays a key role in the carriage of pathogens in food. In this study, we investigated the adhesion ability of SI and recovered E. coli O157:H7 wildtype and its three pili-deficient mutants (curli, type 1 fimbriae, and type IV pili) on six food-related surfaces. Plate counting was used to determine adhesion population after washing and oscillating the surfaces. Spinach exhibited the stronger adhesion population of E. coli O157:H7 than the other fresh produces (p < 0.05). In addition, at least one key pili dominated adhesion on these surfaces, and curli was always included. The adhesion population and contribution of different types of pili were jointly affected by surface and physiological state. This can be attributed to high hydrophobicity and positive charge density on surface and different expression levels of csgB, fimA, fimC and ppdD in SI and recovered cells. Among glucose, mannose, maltose, fructose, lactose, and sucrose, addition of 0.5% mannose could reduce adhesion of cells at all physiological states on stainless steel. Overall, this research will provide support for controlling adhesion of SI and recovered E. coli O157:H7.
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Affiliation(s)
- Hongchen Zhang
- College of Food Science, Southwest University, Chongqing, China
| | - Yujun Zhai
- College of Food Science, Southwest University, Chongqing, China
| | - Kewei Chen
- College of Food Science, Southwest University, Chongqing, China
| | - Hui Shi
- College of Food Science, Southwest University, Chongqing, China.
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Herout R, Khoddami S, Moskalev I, Reicherz A, Chew BH, Armbruster CE, Lange D. Role of Bacterial Surface Components in the Pathogenicity of Proteus mirabilis in a Murine Model of Catheter-Associated Urinary Tract Infection. Pathogens 2023; 12:pathogens12040509. [PMID: 37111395 PMCID: PMC10143806 DOI: 10.3390/pathogens12040509] [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: 01/26/2023] [Revised: 03/07/2023] [Accepted: 03/16/2023] [Indexed: 04/29/2023] Open
Abstract
Proteus mirabilis (PM) is a Gram-negative, rod-shaped bacterium that causes catheter-associated urinary tract infections (CAUTIs). The specific roles of bacterial surface components (BSCs) in PM pathogenicity and CAUTIs remain unknown. To address this knowledge gap, we utilized relevant in vitro adhesion/invasion models and a well-established murine model of CAUTI to assess the ability of wildtype (WT) and seven mutant strains (MSs) of PM with deficiencies in various genes encoding BSCs to undergo the infectious process (including adhesion to catheters) in both model systems. Overall, MSs adhesion to catheters and the different cell types tested was significantly reduced compared to WT, while no invasion of cells was evident at 24 h. In vivo, WT showed a greater number of planktonic (urine) bacteria, bacteria adherent to catheters, and bacteria adherent to/invading bladder tissue when compared to the MSs. Bacterial counts in urine for PMI3191 and waaE mutants were lower than that for WT and other MSs. The complementation of mutated BSC genes resulting in the biggest defects restored the invasion phenotype both in vitro and in vivo. BSCs play a critical role at various steps in the pathogenicity of PM including adhesion to indwelling medical devices and adhesion/invasion of urinary tissue in vivo.
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Affiliation(s)
- Roman Herout
- The Stone Centre at Vancouver General Hospital, Department of Urologic Sciences, University of British Columbia, Vancouver, BC V6H 3Z6, Canada
- Department of Urology, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01062 Dresden, Germany
| | - Sara Khoddami
- The Stone Centre at Vancouver General Hospital, Department of Urologic Sciences, University of British Columbia, Vancouver, BC V6H 3Z6, Canada
| | - Igor Moskalev
- Vancouver Prostate Centre, Department of Urologic Sciences, University of British Columbia, Vancouver, BC V6H 3Z6, Canada
| | - Alina Reicherz
- The Stone Centre at Vancouver General Hospital, Department of Urologic Sciences, University of British Columbia, Vancouver, BC V6H 3Z6, Canada
- Department of Urology, Marien Hospital Herne, Ruhr-University of Bochum, 44649 Herne, Germany
| | - Ben H Chew
- The Stone Centre at Vancouver General Hospital, Department of Urologic Sciences, University of British Columbia, Vancouver, BC V6H 3Z6, Canada
| | - Chelsie E Armbruster
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY 14263, USA
| | - Dirk Lange
- The Stone Centre at Vancouver General Hospital, Department of Urologic Sciences, University of British Columbia, Vancouver, BC V6H 3Z6, Canada
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Rivera-Orduña FN, Pineda-Mendoza RM, Vega-Correa B, López MF, Cano-Ramírez C, Zhang XX, Chen WF, Zúñiga G. A polyphasic taxonomy analysis reveals the presence of an ecotype of Rahnella contaminans associated with the gut of Dendroctonus-bark beetles. Front Microbiol 2023; 14:1171164. [PMID: 37180241 PMCID: PMC10174453 DOI: 10.3389/fmicb.2023.1171164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 04/03/2023] [Indexed: 05/16/2023] Open
Abstract
Species belonging to the genus Rahnella are dominant members of the core gut bacteriome of Dendroctonus-bark beetles, a group of insects that includes the most destructive agents of pine forest in North and Central America, and Eurasia. From 300 isolates recovered from the gut of these beetles, 10 were selected to describe an ecotype of Rahnella contaminans. The polyphasic approach conducted with these isolates included phenotypic characteristics, fatty acid analysis, 16S rRNA gene, multilocus sequence analyses (gyrB, rpoB, infB, and atpD genes), and complete genome sequencing of two isolates, ChDrAdgB13 and JaDmexAd06, representative of the studied set. Phenotypic characterization, chemotaxonomic analysis, phylogenetic analyses of the 16S rRNA gene, and multilocus sequence analysis showed that these isolates belonged to Rahnella contaminans. The G + C content of the genome of ChDrAdgB13 (52.8%) and JaDmexAd06 (52.9%) was similar to those from other Rahnella species. The ANI between ChdrAdgB13 and JaDmexAd06 and Rahnella species including R. contaminans, varied from 84.02 to 99.18%. The phylogenomic analysis showed that both strains integrated a consistent and well-defined cluster, together with R. contaminans. A noteworthy observation is the presence of peritrichous flagella and fimbriae in the strains ChDrAdgB13 and JaDmexAd06. The in silico analysis of genes encoding the flagellar system of these strains and Rahnella species showed the presence of flag-1 primary system encoding peritrichous flagella, as well as fimbriae genes from the families type 1, α, β and σ mainly encoding chaperone/usher fimbriae and other uncharacterized families. All this evidence indicates that isolates from the gut of Dendroctonus-bark beetles are an ecotype of R. contaminans, which is dominant and persistent in all developmental stages of these bark beetles and one of the main members of their core gut bacteriome.
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Affiliation(s)
- Flor N. Rivera-Orduña
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Rosa María Pineda-Mendoza
- Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Brenda Vega-Correa
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - María Fernanda López
- Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Claudia Cano-Ramírez
- Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Xiao Xia Zhang
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Wen Feng Chen
- State Key Laboratory for Agro-Biotechnology and Ministry of Agriculture Key Lab of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Gerardo Zúñiga
- Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
- *Correspondence: Gerardo Zúñiga,
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How Porphyromonas gingivalis Navigate the Map: The Effect of Surface Topography on the Adhesion of Porphyromonas gingivalis on Biomaterials. MATERIALS 2022; 15:ma15144988. [PMID: 35888454 PMCID: PMC9318924 DOI: 10.3390/ma15144988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/25/2022] [Accepted: 07/07/2022] [Indexed: 11/16/2022]
Abstract
The main purpose of this study is to develop an understanding of how Porphyromonas gingivalis responds to subperiosteal implant surface topography. A literature review was drawn from various electronic databases from 2000 to 2021. The two main keywords used were “Porphyromonas gingivalis” and “Surface Topography”. We excluded all reviews and or meta-analysis articles, articles not published in English, and articles with no surface characterization process or average surface roughness (Ra) value. A total of 26 selected publications were then included in this study. All research included showed the effect of topography on Porphyromonas gingivalis to various degrees. It was found that topography features such as size and shape affected Porphyromonas gingivalis adhesion to subperiosteal implant materials. In general, a smaller Ra value reduces Porphyromonas gingivalis regardless of the type of materials, with a threshold of 0.3 µm for titanium.
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Cheng RA, Orsi RH, Wiedmann M. The Number and Type of Chaperone-Usher Fimbriae Reflect Phylogenetic Clade Rather than Host Range in Salmonella. mSystems 2022; 7:e0011522. [PMID: 35467401 PMCID: PMC9238391 DOI: 10.1128/msystems.00115-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 04/03/2022] [Indexed: 01/21/2023] Open
Abstract
Salmonella is one of the most successful foodborne pathogens worldwide, owing in part to its ability to colonize or infect a wide range of hosts. Salmonella serovars are known to encode a variety of different fimbriae (hairlike organelles that facilitate binding to surfaces); however, the distribution, number, and sequence diversity of fimbriae encoded across different lineages of Salmonella were unknown. We queried whole-genome sequence (WGS) data for 242 Salmonella enterica subsp. enterica (subspecies enterica) isolates from the top 217 serovars associated with isolation from humans and agricultural animals; this effort identified 2,894 chaperone-usher (CU)-type fimbrial usher sequences, representing the most conserved component of CU fimbriae. On average, isolates encoded 12 different CU fimbrial ushers (6 to 18 per genome), although the distribution varied significantly (P = 1.328E-08) by phylogenetic clade, with isolates in section Typhi having significantly fewer fimbrial ushers than isolates in clade A2 (medians = 10 and 12 ushers, respectively). Characterization of fimbriae in additional non-enterica subspecies genomes suggested that 8 fimbrial ushers were classified as being unique to subspecies enterica isolates, suggesting that the majority of fimbriae were most likely acquired prior to the divergence of subspecies enterica. Characterization of mobile elements suggested that plasmids represent an important vehicle facilitating the acquisition of a wide range of fimbrial ushers, particularly for the acquisition of fimbriae from other Gram-negative genera. Overall, our results suggest that differences in the number and type of fimbriae encoded most likely reflect differences in phylogenetic clade rather than differences in host range. IMPORTANCE Fimbriae of the CU assembly pathway represent important organelles that mediate Salmonella's interactions with host tissues and abiotic surfaces. Our analyses provide a comprehensive overview of the diversity of CU fimbriae in Salmonella spp., highlighting that the majority of CU fimbriae are distributed broadly across multiple subspecies and suggesting that acquisition most likely occurred prior to the divergence of subspecies enterica. Our data also suggest that plasmids represent the primary vehicles facilitating the horizontal transfer of diverse CU fimbriae in Salmonella. Finally, the observed high sequence similarity between some ushers suggests that different names may have been assigned to closely related fimbrial ushers that likely should be represented by a single designation. This highlights the need to establish standard criteria for fimbria classification and nomenclature, which will also facilitate future studies seeking to associate virulence factors with adaptation to or differences in the likelihood of causing disease in a given host.
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Affiliation(s)
- Rachel A. Cheng
- Department of Food Science, Cornell University, Ithaca, New York, USA
| | - Renato H. Orsi
- Department of Food Science, Cornell University, Ithaca, New York, USA
| | - Martin Wiedmann
- Department of Food Science, Cornell University, Ithaca, New York, USA
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Cheng RA, Wiedmann M. Recent Advances in Our Understanding of the Diversity and Roles of Chaperone-Usher Fimbriae in Facilitating Salmonella Host and Tissue Tropism. Front Cell Infect Microbiol 2021; 10:628043. [PMID: 33614531 PMCID: PMC7886704 DOI: 10.3389/fcimb.2020.628043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 12/21/2020] [Indexed: 01/04/2023] Open
Abstract
Salmonella enterica is one of the most diverse and successful pathogens, representing a species with >2,600 serovars with a variety of adaptations that enable colonization and infection of a wide range of hosts. Fimbriae, thin hair-like projections that cover the surface of Salmonella, are thought to be the primary organelles that mediate Salmonella's interaction with, and adherence to, the host intestinal epithelium, representing an important step in the infection process. The recent expansion in genome sequencing efforts has enabled the discovery of novel fimbriae, thereby providing new perspectives on fimbrial diversity and distribution among a broad number of serovars. In this review, we provide an updated overview of the evolutionary events that shaped the Salmonella chaperone-usher fimbriome in light of recent phylogenetic studies describing the population structure of Salmonella enterica. Furthermore, we discuss the complexities of the chaperone-usher fimbriae-mediated host-pathogen interactions and the apparent redundant roles of chaperone-usher fimbriae in host and tissue tropism.
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Affiliation(s)
- Rachel A. Cheng
- Department of Food Science, Cornell University, Ithaca, NY, United States
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Jang H, Gopinath GR, Eshwar A, Srikumar S, Nguyen S, Gangiredla J, Patel IR, Finkelstein SB, Negrete F, Woo J, Lee Y, Fanning S, Stephan R, Tall BD, Lehner A. The Secretion of Toxins and Other Exoproteins of Cronobacter: Role in Virulence, Adaption, and Persistence. Microorganisms 2020; 8:E229. [PMID: 32046365 PMCID: PMC7074816 DOI: 10.3390/microorganisms8020229] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 01/28/2020] [Accepted: 02/06/2020] [Indexed: 12/29/2022] Open
Abstract
: Cronobacter species are considered an opportunistic group of foodborne pathogenic bacteria capable of causing both intestinal and systemic human disease. This review describes common virulence themes shared among the seven Cronobacter species and describes multiple exoproteins secreted by Cronobacter, many of which are bacterial toxins that may play a role in human disease. The review will particularly concentrate on the virulence factors secreted by C. sakazakii, C. malonaticus, and C. turicensis, which are the primary human pathogens of interest. It has been discovered that various species-specific virulence factors adversely affect a wide range of eukaryotic cell processes including protein synthesis, cell division, and ion secretion. Many of these factors are toxins which have been shown to also modulate the host immune response. These factors are encoded on a variety of mobile genetic elements such as plasmids and transposons; this genomic plasticity implies ongoing re-assortment of virulence factor genes which has complicated our efforts to categorize Cronobacter into sharply defined genomic pathotypes.
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Affiliation(s)
- Hyein Jang
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA; (H.J.); (J.G.); (F.N.); (J.W.); (Y.L.)
| | - Gopal R. Gopinath
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA; (H.J.); (J.G.); (F.N.); (J.W.); (Y.L.)
| | - Athmanya Eshwar
- Institute for Food Safety and Hygiene, University of Zurich, Zurich CH-8006 Zürich, Switzerland; (A.E.); (R.S.); (A.L.)
| | - Shabarinath Srikumar
- UCD-Centre for Food Safety, Science Centre South, University College Dublin, Dublin Belfield, Dublin 4, D04 V1W8, Ireland; (S.S.); (S.N.); (S.F.)
| | - Scott Nguyen
- UCD-Centre for Food Safety, Science Centre South, University College Dublin, Dublin Belfield, Dublin 4, D04 V1W8, Ireland; (S.S.); (S.N.); (S.F.)
| | - Jayanthi Gangiredla
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA; (H.J.); (J.G.); (F.N.); (J.W.); (Y.L.)
| | - Isha R. Patel
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA; (H.J.); (J.G.); (F.N.); (J.W.); (Y.L.)
| | - Samantha B. Finkelstein
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA; (H.J.); (J.G.); (F.N.); (J.W.); (Y.L.)
| | - Flavia Negrete
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA; (H.J.); (J.G.); (F.N.); (J.W.); (Y.L.)
| | - JungHa Woo
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA; (H.J.); (J.G.); (F.N.); (J.W.); (Y.L.)
| | - YouYoung Lee
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA; (H.J.); (J.G.); (F.N.); (J.W.); (Y.L.)
| | - Séamus Fanning
- UCD-Centre for Food Safety, Science Centre South, University College Dublin, Dublin Belfield, Dublin 4, D04 V1W8, Ireland; (S.S.); (S.N.); (S.F.)
| | - Roger Stephan
- Institute for Food Safety and Hygiene, University of Zurich, Zurich CH-8006 Zürich, Switzerland; (A.E.); (R.S.); (A.L.)
| | - Ben D. Tall
- Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, Laurel, MD 20708, USA; (H.J.); (J.G.); (F.N.); (J.W.); (Y.L.)
| | - Angelika Lehner
- Institute for Food Safety and Hygiene, University of Zurich, Zurich CH-8006 Zürich, Switzerland; (A.E.); (R.S.); (A.L.)
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Abstract
Proteus mirabilis, a Gram-negative rod-shaped bacterium most noted for its swarming motility and urease activity, frequently causes catheter-associated urinary tract infections (CAUTIs) that are often polymicrobial. These infections may be accompanied by urolithiasis, the development of bladder or kidney stones due to alkalinization of urine from urease-catalyzed urea hydrolysis. Adherence of the bacterium to epithelial and catheter surfaces is mediated by 17 different fimbriae, most notably MR/P fimbriae. Repressors of motility are often encoded by these fimbrial operons. Motility is mediated by flagella encoded on a single contiguous 54-kb chromosomal sequence. On agar plates, P. mirabilis undergoes a morphological conversion to a filamentous swarmer cell expressing hundreds of flagella. When swarms from different strains meet, a line of demarcation, a "Dienes line," develops due to the killing action of each strain's type VI secretion system. During infection, histological damage is caused by cytotoxins including hemolysin and a variety of proteases, some autotransported. The pathogenesis of infection, including assessment of individual genes or global screens for virulence or fitness factors has been assessed in murine models of ascending urinary tract infections or CAUTIs using both single-species and polymicrobial models. Global gene expression studies performed in culture and in the murine model have revealed the unique metabolism of this bacterium. Vaccines, using MR/P fimbria and its adhesin, MrpH, have been shown to be efficacious in the murine model. A comprehensive review of factors associated with urinary tract infection is presented, encompassing both historical perspectives and current advances.
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Chahales P, Thanassi DG. Structure, Function, and Assembly of Adhesive Organelles by Uropathogenic Bacteria. Microbiol Spectr 2015; 3:10.1128/microbiolspec.UTI-0018-2013. [PMID: 26542038 PMCID: PMC4638162 DOI: 10.1128/microbiolspec.uti-0018-2013] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Indexed: 01/02/2023] Open
Abstract
Bacteria assemble a wide range of adhesive proteins, termed adhesins, to mediate binding to receptors and colonization of surfaces. For pathogenic bacteria, adhesins are critical for early stages of infection, allowing the bacteria to initiate contact with host cells, colonize different tissues, and establish a foothold within the host. The adhesins expressed by a pathogen are also critical for bacterial-bacterial interactions and the formation of bacterial communities, including biofilms. The ability to adhere to host tissues is particularly important for bacteria that colonize sites such as the urinary tract, where the flow of urine functions to maintain sterility by washing away non-adherent pathogens. Adhesins vary from monomeric proteins that are directly anchored to the bacterial surface to polymeric, hair-like fibers that extend out from the cell surface. These latter fibers are termed pili or fimbriae, and were among the first identified virulence factors of uropathogenic Escherichia coli. Studies since then have identified a range of both pilus and non-pilus adhesins that contribute to bacterial colonization of the urinary tract, and have revealed molecular details of the structures, assembly pathways, and functions of these adhesive organelles. In this review, we describe the different types of adhesins expressed by both Gram-negative and Gram-positive uropathogens, what is known about their structures, how they are assembled on the bacterial surface, and the functions of specific adhesins in the pathogenesis of urinary tract infections.
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Affiliation(s)
- Peter Chahales
- Center for Infectious Diseases and Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794
| | - David G Thanassi
- Center for Infectious Diseases and Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794
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Thanassi DG, Bliska JB, Christie PJ. Surface organelles assembled by secretion systems of Gram-negative bacteria: diversity in structure and function. FEMS Microbiol Rev 2012; 36:1046-82. [PMID: 22545799 PMCID: PMC3421059 DOI: 10.1111/j.1574-6976.2012.00342.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Revised: 03/08/2012] [Accepted: 04/13/2012] [Indexed: 11/29/2022] Open
Abstract
Gram-negative bacteria express a wide variety of organelles on their cell surface. These surface structures may be the end products of secretion systems, such as the hair-like fibers assembled by the chaperone/usher (CU) and type IV pilus pathways, which generally function in adhesion to surfaces and bacterial-bacterial and bacterial-host interactions. Alternatively, the surface organelles may be integral components of the secretion machinery itself, such as the needle complex and pilus extensions formed by the type III and type IV secretion systems, which function in the delivery of bacterial effectors inside host cells. Bacterial surface structures perform functions critical for pathogenesis and have evolved to withstand forces exerted by the external environment and cope with defenses mounted by the host immune system. Given their essential roles in pathogenesis and exposed nature, bacterial surface structures also make attractive targets for therapeutic intervention. This review will describe the structure and function of surface organelles assembled by four different Gram-negative bacterial secretion systems: the CU pathway, the type IV pilus pathway, and the type III and type IV secretion systems.
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Affiliation(s)
- David G Thanassi
- Center for Infectious Diseases, Stony Brook University, Stony Brook, NY 11794-5120, USA.
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