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Liu C, Shao J, Ma X, Tang Y, Li J, Li H, Chi X, Liu Z. A novel two-component system contributing the catabolism of c-di-GMP influences virulence in Aeromonas veronii. Front Microbiol 2025; 16:1527317. [PMID: 39980697 PMCID: PMC11841396 DOI: 10.3389/fmicb.2025.1527317] [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: 11/13/2024] [Accepted: 01/16/2025] [Indexed: 02/22/2025] Open
Abstract
Introduction Response regulators from diverse two-component systems often function as diguanylate cyclases or phosphodiesterases, thereby enabling precise regulation of intracellular c-di-GMP levels to control bacterial virulence and motility. However, the regulatory mechanisms of c-di-GMP require further elucidation. Methods This study confirmed that ArrS and ArrR form a two-component system via structural analysis, two-hybrid, and phosphodiesterase activity detection. To evaluate the impact of ArrS/ArrR on intracellular c-di-GMP levels, biofilm detection, motility detection, fluorescence reporter plasmids, and LC-MS/MS analysis were employed. One-hybrid, EMSA, and RT-qPCR were used to demonstrate the function of ArgR on arrSR promoter. The roles of ArrS/ArrR in Aeromonas veronii were investigated using RT-qPCR, murine model, and proteomics. Results ArrS and ArrR constituted a two-component system in Aeromonas veronii and were transcriptionally repressed by ArgR. ArrR exhibited phosphodiesterase activity, which is inhibited through phosphorylation mediated by ArrS. In Aeromonas veronii, ArrS/ArrR significantly altered the intracellular c-di-GMP levels. In a murine model, ΔarrS exhibited increased pathogenicity, leading to elevated TNF-α and IFN-γ levels in serum, and severer toxicity to spleen and kidney. These effects might be elucidated by the upregulated inflammation-associated proteins in ΔarrS. Moreover, the exonuclease RecB was also up-regulated in ΔarrS. Discussion We elucidated the regulatory mechanism of ArrS/ArrR on intracellular c-di-GMP levels and its impact on the virulence in Aeromonas veronii, and discussed the intricate relationship between c-di-GMP metabolism and arginine metabolism.
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Affiliation(s)
| | | | | | | | | | | | | | - Zhu Liu
- School of Life and Health Sciences, Hainan University, Haikou, China
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2
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Ojaimi Loibman S, Quintana-Hayashi MP, Santos L, Lindén SK. Aeromonas salmonicida AI-1 and AI-2 quorum sensing pathways are differentially regulated by rainbow trout mucins and during in vivo colonization. FISH & SHELLFISH IMMUNOLOGY 2024; 153:109862. [PMID: 39209006 DOI: 10.1016/j.fsi.2024.109862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 08/26/2024] [Accepted: 08/26/2024] [Indexed: 09/04/2024]
Abstract
Aeromonas salmonicida is an opportunistic pathogen with relevance for aquaculture. Fish epithelia are covered by a mucus layer, composed mainly by highly glycosylated mucins, which are the first point of contact between fish and pathogens. Quorum sensing (QS), a bacterial communication mechanism through secreted autoinducer signals that governs gene expression, influences bacterial growth and virulence. The main A. salmonicida autoinducers are mediated by the luxS and asaI genes, corresponding to inter- and intraspecies communication, respectively. The aim of this study was to determine the effect of the mucins that pathogens encounter during colonization of the gill and skin on A. salmonicida QS. We found that expression of A. salmonicida asaI, but not luxS, was increased after culture at 20 °C compared to 10 °C. Rainbow trout gill and skin mucins up-regulated asaI expression 2-fold but down-regulated luxS 10-fold. The downregulation of luxS was reflected by a reduction in autoinducer-2 secretion. Mucins isolated from skin had a stronger inhibitory effect than mucins isolated from gills on both luxS expression and A1-2 secretion, consistent with a higher relative abundance of N-Acetylneuraminic acid on skin mucins than on gill mucins. Reduction of AI-2 production by mucins or luxS-deletion lead to a reduced A. salmonicida auto-aggregation. Furthermore, after colonization of the gill, luxS was down regulated whereas asaI expression was upregulated. Both in vivo and in vitro, the expression of luxS and asaI were thus differentially regulated, frequently in an inverse manner. The strong AI-2 inhibiting effect of the skin mucins is likely part of the mucin-based defense against pathogens.
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Affiliation(s)
| | | | - Licínia Santos
- Department of Medical Chemistry and Cell Biology, University of Gothenburg, Sweden
| | - Sara K Lindén
- Department of Medical Chemistry and Cell Biology, University of Gothenburg, Sweden.
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3
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Islam SI, Mahfuj S, Baqar Z, Asadujjaman M, Islam MJ, Alsiwiehri N, Almehmadi M, Sanjida S, Ahammad F. Bacterial diseases of Asian sea bass ( Lates calcarifer): A review for health management strategies and future aquaculture sustainability. Heliyon 2024; 10:e29793. [PMID: 38707314 PMCID: PMC11068540 DOI: 10.1016/j.heliyon.2024.e29793] [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: 12/23/2023] [Revised: 04/05/2024] [Accepted: 04/15/2024] [Indexed: 05/07/2024] Open
Abstract
The advent of aquaculture has been one of the most significant shifts in world food supply during the last century. Aquaculture has rapidly expanded and become a global food industry, spurred by population expansion, increased seafood consumption, and decreased captured fisheries. Nonetheless, the exponential growth of aquaculture has emerged as a significant contributor to anthropogenic changes. Unexpectedly, the result has focused in the emergence and spread of new diseases. The Asian sea bass (Lates calcarifer) is an economically important species in aquaculture, contributing significantly to the global seafood market. However, bacterial diseases have emerged as a major concern, affecting both wild and cultured populations of this species. The most prevalent bacterial pathogens are streptococcus, vibriosis, nocardiosis, tenacibaculosis, and pot-belly disease. Therefore, this review aims to comprehensively analyze both emerging and non-emerging bacterial diseases affecting L. calcarifer and explore potential management approaches for their control. Through an extensive literature survey and critical evaluation of research findings, this review highlights the current understanding of bacterial diseases in L. calcarifer and proposes strategies for better disease management. In addition, this review looks at the rise and characteristics of aquaculture, the major bacterial pathogens of L. calcarifer and their effects, and the specific attributes of disease emergence in an aquatic rather than terrestrial context. It also considers the potential for future disease emergence in L. calcarifer due to aquaculture expansion and climate changes.
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Affiliation(s)
- Sk Injamamul Islam
- Department of Fisheries and Marine Bioscience, Faculty of Biological Science and Technology, Jashore University of Science and Technology, Jashore, 7408, Bangladesh
- Department of Veterinary Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Sarower Mahfuj
- Department of Fisheries and Marine Bioscience, Faculty of Biological Science and Technology, Jashore University of Science and Technology, Jashore, 7408, Bangladesh
| | - Zulqarnain Baqar
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Md Asadujjaman
- Department of Aquaculture, Khulna Agricultural University, Khulna, 9100, Bangladesh
| | - Md Jakiul Islam
- Faculty of Fisheries, Sylhet Agricultural University, Sylhet, 3100, Bangladesh
| | - Naif Alsiwiehri
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia
| | - Mazen Almehmadi
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia
| | - Saloa Sanjida
- Department of Environmental Science and Technology, Faculty of Applied Science and Technology, Jashore University of Science and Technology, Jashore, 7408, Bangladesh
| | - Foysal Ahammad
- Division of Biological and Biomedical Sciences, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
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Wang L, Li H, Chen J, Wang Y, Gu Y, Jiu M. Antibacterial Mechanisms and Antivirulence Activities of Oridonin against Pathogenic Aeromonas hydrophila AS 1.1801. Microorganisms 2024; 12:415. [PMID: 38399819 PMCID: PMC10891661 DOI: 10.3390/microorganisms12020415] [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: 01/18/2024] [Revised: 02/08/2024] [Accepted: 02/15/2024] [Indexed: 02/25/2024] Open
Abstract
Aeromonas hydrophila, a Gram-negative bacterium widely found in freshwater environments, acts as a common conditional pathogen affecting humans, livestock, and aquatic animals. In this study, the impact of oridonin, an ent-kaurane diterpenoid compound derived from Rabdosia rubescens, on the virulence factors of A. hydrophila AS 1.1801 and its antibacterial mechanism was elucidated. The minimum inhibitory concentration (MIC) of oridonin against A. hydrophila AS 1.1801 was 100 μg/mL. Oridonin at inhibitory concentrations could significantly increase the electrical conductivity in the supernatant and escalate nucleic acid leakage (p < 0.01). This effect was concomitant with observed distortions in bacterial cells, the formation of cytoplasmic cavities, cellular damage, and pronounced inhibition of protein and nucleic acid synthesis. Additionally, oridonin at inhibitory levels exhibited a noteworthy suppressive impact on A. hydrophila AS 1.1801 across biofilm formation, motility, hemolytic activity, lipase activity, and protease activity (p < 0.05), demonstrating a dose-dependent enhancement. qRT-PCR analysis showed that the gene expression of luxR, qseB and omp were significantly downregulated after oridonin treatment in A. hydrophila AS 1.1801 (p < 0.05). Our results indicated that oridonin possessed significant antibacterial and anti-virulence effects on A. hydrophila AS 1.1801.
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Affiliation(s)
- Lunji Wang
- Key Laboratory of Microbial Resources Development and Utilization, Henan University of Science and Technology, Luoyang 471023, China; (L.W.); (J.C.)
- College of Food and Bioengineering, Henan University of Science and Technology, Luoyang 471023, China; (H.L.); (Y.W.); (Y.G.)
| | - Huijuan Li
- College of Food and Bioengineering, Henan University of Science and Technology, Luoyang 471023, China; (H.L.); (Y.W.); (Y.G.)
| | - Jinhao Chen
- Key Laboratory of Microbial Resources Development and Utilization, Henan University of Science and Technology, Luoyang 471023, China; (L.W.); (J.C.)
| | - Yi Wang
- College of Food and Bioengineering, Henan University of Science and Technology, Luoyang 471023, China; (H.L.); (Y.W.); (Y.G.)
| | - Yuqing Gu
- College of Food and Bioengineering, Henan University of Science and Technology, Luoyang 471023, China; (H.L.); (Y.W.); (Y.G.)
| | - Min Jiu
- Key Laboratory of Microbial Resources Development and Utilization, Henan University of Science and Technology, Luoyang 471023, China; (L.W.); (J.C.)
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Neil B, Cheney GL, Rosenzweig JA, Sha J, Chopra AK. Antimicrobial resistance in aeromonads and new therapies targeting quorum sensing. Appl Microbiol Biotechnol 2024; 108:205. [PMID: 38349402 PMCID: PMC10864486 DOI: 10.1007/s00253-024-13055-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 01/31/2024] [Accepted: 02/05/2024] [Indexed: 02/15/2024]
Abstract
Aeromonas species (spp.) are well-known fish pathogens, several of which have been recognized as emerging human pathogens. The organism is capable of causing a wide spectrum of diseases in humans, ranging from gastroenteritis, wound infections, and septicemia to devastating necrotizing fasciitis. The systemic form of infection is often fatal, particularly in patients with underlying chronic diseases. Indeed, recent trends demonstrate rising numbers of hospital-acquired Aeromonas infections, especially in immuno-compromised individuals. Additionally, Aeromonas-associated antibiotic resistance is an increasing challenge in combating both fish and human infections. The acquisition of antibiotic resistance is related to Aeromonas' innate transformative properties including its ability to share plasmids and integron-related gene cassettes between species and with the environment. As a result, alternatives to antibiotic treatments are desperately needed. In that vein, many treatments have been proposed and studied extensively in the fish-farming industry, including treatments that target Aeromonas quorum sensing. In this review, we discuss current strategies targeting quorum sensing inhibition and propose that such studies empower the development of novel chemotherapeutic approaches to combat drug-resistant Aeromonas spp. infections in humans. KEY POINTS: • Aeromonas notoriously acquires and maintains antimicrobial resistance, making treatment options limited. • Quorum sensing is an essential virulence mechanism in Aeromonas infections. • Inhibiting quorum sensing can be an effective strategy in combating Aeromonas infections in animals and humans.
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Affiliation(s)
- Blake Neil
- Department of Microbiology and Immunology, Medical Branch, University of Texas, Galveston, TX, 77555, USA
| | - Gabrielle L Cheney
- John Sealy School of Medicine, Medical Branch, University of Texas, Galveston, TX, 77555, USA
| | - Jason A Rosenzweig
- Department of Biology, Texas Southern University, Houston, TX, 77004, USA
| | - Jian Sha
- Department of Microbiology and Immunology, Medical Branch, University of Texas, Galveston, TX, 77555, USA
| | - Ashok K Chopra
- Department of Microbiology and Immunology, Medical Branch, University of Texas, Galveston, TX, 77555, USA.
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Qin T, Chen K, Xi B, Pan L, Xie J, Lu L, Liu K. In Vitro Antibiofilm Activity of Resveratrol against Aeromonas hydrophila. Antibiotics (Basel) 2023; 12:antibiotics12040686. [PMID: 37107048 PMCID: PMC10135085 DOI: 10.3390/antibiotics12040686] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 03/23/2023] [Accepted: 03/27/2023] [Indexed: 04/03/2023] Open
Abstract
Aeromonas hydrophila is a Gram-negative bacterium that widely exists in various aquatic environments and causes septicemia in fish and humans. Resveratrol, a natural polyterpenoid product, has potential chemo-preventive and antibacterial properties. In this study, we investigated the effect of resveratrol on A. hydrophila biofilm formation and motility. The results demonstrated that resveratrol, at sub-MIC levels, can significantly inhibit the biofilm formation of A. hydrophila, and the biofilm was decreased with increasing concentrations. The motility assay showed that resveratrol could diminish the swimming and swarming motility of A. hydrophila. Transcriptome analyses (RNA-seq) showed that A. hydrophila treated with 50 and 100 μg/mL resveratrol, respectively, presented 230 and 308 differentially expressed genes (DEGs), including 90 or 130 upregulated genes and 130 or 178 downregulated genes. Among them, genes related to flagellar, type IV pilus and chemotaxis were significantly repressed. In addition, mRNA of virulence factors OmpA, extracellular proteases, lipases and T6SS were dramatically suppressed. Further analysis revealed that the major DEGs involved in flagellar assembly and bacterial chemotaxis pathways could be regulated by cyclic-di-guanosine monophosphate (c-di-GMP)- and LysR-Type transcriptional regulator (LTTR)-dependent quorum sensing (QS) systems. Overall, our results indicate that resveratrol can inhibit A. hydrophila biofilm formation by disturbing motility and QS systems, and can be used as a promising candidate drug against motile Aeromonad septicemia.
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Zhu Y, Dou Q, Du L, Wang Y. QseB/QseC: a two-component system globally regulating bacterial behaviors. Trends Microbiol 2023:S0966-842X(23)00046-X. [PMID: 36849330 DOI: 10.1016/j.tim.2023.02.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/06/2023] [Accepted: 02/07/2023] [Indexed: 03/01/2023]
Abstract
QseB/QseC is a two-component system that is involved in the regulation of multiple bacterial behaviors by regulating quorum sensing, bacterial pathogenicity, and antibiotic resistance. Thus, QseB/QseC could provide a target for new antibiotic development. Recently, QseB/QseC has been found to confer survival advantages to environmental bacteria under stress conditions. The molecular mechanistic understanding of QseB/QseC has become an active area of research and revealed some emerging themes, including a deeper understanding of QseB/QseC regulation in different pathogens and environmental bacteria, the functional difference of QseB/QseC among species, and the possibility of analyzing QseB/QseC evolution. Here, we discuss the progression of QseB/QseC studies and describe several unresolved issues and future directions. Resolving these issues is among the challenges of future QseB/QseC studies.
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Affiliation(s)
- Yuxiang Zhu
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China
| | - Qin Dou
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China
| | - Liangcheng Du
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Yan Wang
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao 266003, China.
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8
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Zhao Y, Liu Y, Li N, Muhammad M, Gong S, Ju J, Cai T, Wang J, Zhao B, Liu D. Significance of broad-spectrum racemases for the viability and pathogenicity of Aeromonas hydrophila. Future Microbiol 2022; 17:251-265. [PMID: 35152710 DOI: 10.2217/fmb-2021-0112] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aim: To investigate the function of broad-spectrum racemases in Aeromonas hydrophila (BsrA). Results: The A. hydrophila gene encoding BsrA (bsr) mutants (AHΔbsr) exhibited a significant decrease in growth, motility, extracellular protease production and biofilm formation compared with the wild-type. Furthermore, bsr gene knockout instigated cell wall damage compared with the wild-type strains. The survival rate and replication capability in the blood and organs of the AHΔbsr-infected mice were significantly decreased. The degree of tissue injury in the AHΔbsr-infected group was lower than that of the wild-type-infected group. Moreover, there was a significant decrease in the expression of 12 AHΔbsr virulence genes. Conclusion: The bsr gene is essential for the viability and virulence of A. hydrophila.
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Affiliation(s)
- Yi Zhao
- College of Life Science, Hebei Normal University, Shijiazhuang, 050024, China
| | - Yaoyao Liu
- College of Life Science, Hebei Normal University, Shijiazhuang, 050024, China
| | - Na Li
- College of Life Science, Hebei Normal University, Shijiazhuang, 050024, China
| | - Murtala Muhammad
- Department of Biochemistry, Kano University of Science and Technology, Wudil, 713281, Nigeria
| | - Siyu Gong
- College of Life Science, Hebei Normal University, Shijiazhuang, 050024, China
| | - Jiansong Ju
- College of Life Science, Hebei Normal University, Shijiazhuang, 050024, China
| | - Tongxuan Cai
- College of Life Science, Hebei Normal University, Shijiazhuang, 050024, China
| | - Jialu Wang
- College of Life Science, Hebei Normal University, Shijiazhuang, 050024, China
| | - Baohua Zhao
- College of Life Science, Hebei Normal University, Shijiazhuang, 050024, China
| | - Dong Liu
- College of Life Science, Hebei Normal University, Shijiazhuang, 050024, China
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Complete genome sequence of fish-pathogenic Aeromonas hydrophila HX-3 and a comparative analysis: insights into virulence factors and quorum sensing. Sci Rep 2020; 10:15479. [PMID: 32968153 PMCID: PMC7512022 DOI: 10.1038/s41598-020-72484-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 08/31/2020] [Indexed: 12/19/2022] Open
Abstract
The gram-negative, aerobic, rod-shaped bacterium Aeromonas hydrophila, the causative agent of motile aeromonad septicaemia, has attracted increasing attention due to its high pathogenicity. Here, we constructed the complete genome sequence of a virulent strain, A. hydrophila HX-3 isolated from Pseudosciaena crocea and performed comparative genomics to investigate its virulence factors and quorum sensing features in comparison with those of other Aeromonas isolates. HX-3 has a circular chromosome of 4,941,513 bp with a 61.0% G + C content encoding 4483 genes, including 4318 protein-coding genes, and 31 rRNA, 127 tRNA and 7 ncRNA operons. Seventy interspersed repeat and 153 tandem repeat sequences, 7 transposons, 8 clustered regularly interspaced short palindromic repeats, and 39 genomic islands were predicted in the A. hydrophila HX-3 genome. Phylogeny and pan-genome were also analyzed herein to confirm the evolutionary relationships on the basis of comparisons with other fully sequenced Aeromonas genomes. In addition, the assembled HX-3 genome was successfully annotated against the Cluster of Orthologous Groups of proteins database (76.03%), Gene Ontology database (18.13%), and Kyoto Encyclopedia of Genes and Genome pathway database (59.68%). Two-component regulatory systems in the HX-3 genome and virulence factors profiles through comparative analysis were predicted, providing insights into pathogenicity. A large number of genes related to the AHL-type 1 (ahyI, ahyR), LuxS-type 2 (luxS, pfs, metEHK, litR, luxOQU) and QseBC-type 3 (qseB, qseC) autoinducer systems were also identified. As a result of the expression of the ahyI gene in Escherichia coli BL21 (DE3), combined UPLC-MS/MS profiling led to the identification of several new N-acyl-homoserine lactone compounds synthesized by AhyI. This genomic analysis determined the comprehensive QS systems of A. hydrophila, which might provide novel information regarding the mechanisms of virulence signatures correlated with QS.
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Kozlova EV, Hegde S, Roundy CM, Golovko G, Saldaña MA, Hart CE, Anderson ER, Hornett EA, Khanipov K, Popov VL, Pimenova M, Zhou Y, Fovanov Y, Weaver SC, Routh AL, Heinz E, Hughes GL. Microbial interactions in the mosquito gut determine Serratia colonization and blood-feeding propensity. ISME JOURNAL 2020; 15:93-108. [PMID: 32895494 PMCID: PMC7852612 DOI: 10.1038/s41396-020-00763-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 08/05/2020] [Accepted: 08/25/2020] [Indexed: 12/14/2022]
Abstract
How microbe–microbe interactions dictate microbial complexity in the mosquito gut is unclear. Previously we found that, Serratia, a gut symbiont that alters vector competence and is being considered for vector control, poorly colonized Aedes aegypti yet was abundant in Culex quinquefasciatus reared under identical conditions. To investigate the incompatibility between Serratia and Ae. aegypti, we characterized two distinct strains of Serratia marcescens from Cx. quinquefasciatus and examined their ability to infect Ae. aegypti. Both Serratia strains poorly infected Ae. aegypti, but when microbiome homeostasis was disrupted, the prevalence and titers of Serratia were similar to the infection in its native host. Examination of multiple genetically diverse Ae. aegypti lines found microbial interference to S. marcescens was commonplace, however, one line of Ae. aegypti was susceptible to infection. Microbiome analysis of resistant and susceptible lines indicated an inverse correlation between Enterobacteriaceae bacteria and Serratia, and experimental co-infections in a gnotobiotic system recapitulated the interference phenotype. Furthermore, we observed an effect on host behavior; Serratia exposure to Ae. aegypti disrupted their feeding behavior, and this phenotype was also reliant on interactions with their native microbiota. Our work highlights the complexity of host–microbe interactions and provides evidence that microbial interactions influence mosquito behavior.
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Affiliation(s)
- Elena V Kozlova
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA
| | - Shivanand Hegde
- Departments of Vector Biology and Tropical Disease Biology, Centre for Neglected Tropical Disease, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Christopher M Roundy
- World Reference Center for Emerging Viruses and Arboviruses, Institute for Human Infections and Immunity, and Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA
| | - George Golovko
- Department of Pharmacology and Toxicology, Sealy Center for Structural Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Miguel A Saldaña
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA.,Department of Paediatrics and Tropical Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Charles E Hart
- The Institute for Translational Science, University of Texas Medical Branch, Galveston, TX, USA.,Institute for Global Health and Translational Science and SUNY Center for Environmental Health and Medicine, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Enyia R Anderson
- Departments of Vector Biology and Tropical Disease Biology, Centre for Neglected Tropical Disease, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Emily A Hornett
- Departments of Vector Biology and Tropical Disease Biology, Centre for Neglected Tropical Disease, Liverpool School of Tropical Medicine, Liverpool, UK.,Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Kamil Khanipov
- Department of Pharmacology and Toxicology, Sealy Center for Structural Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Vsevolod L Popov
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA
| | - Maria Pimenova
- Department of Pharmacology and Toxicology, Sealy Center for Structural Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Yiyang Zhou
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Yuriy Fovanov
- Department of Pharmacology and Toxicology, Sealy Center for Structural Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Scott C Weaver
- World Reference Center for Emerging Viruses and Arboviruses, Institute for Human Infections and Immunity, and Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA
| | - Andrew L Routh
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Eva Heinz
- Departments of Vector Biology and Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Grant L Hughes
- Departments of Vector Biology and Tropical Disease Biology, Centre for Neglected Tropical Disease, Liverpool School of Tropical Medicine, Liverpool, UK.
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Ouyang K, Mortimer M, Holden PA, Cai P, Wu Y, Gao C, Huang Q. Towards a better understanding of Pseudomonas putida biofilm formation in the presence of ZnO nanoparticles (NPs): Role of NP concentration. ENVIRONMENT INTERNATIONAL 2020; 137:105485. [PMID: 32004708 DOI: 10.1016/j.envint.2020.105485] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 12/13/2019] [Accepted: 01/11/2020] [Indexed: 05/07/2023]
Abstract
Elucidating the effects of nanoparticles (NPs) on key bacterial functions not only deepens our understanding of nano-toxicity mechanisms, but also guides us in the design criteria for manufacturing safe nanomaterials. In this study, bacterial growth, biofilm development and the expression of biofilm-related genes were monitored in Pseudomonas putida KT2440, a plant-beneficial bacterium, following exposure to ZnO NPs. Low concentrations of NPs (0.5-30 mg L-1) significantly promoted bacterial growth and biofilm formation, while higher concentrations (>30 mg L-1) significantly inhibited biofilm formation. Confocal laser scanning microscopy revealed that microscope slides coated with 0.5 mg L-1 of ZnO NPs showed enhanced bacterial colonization and biomass production, but at higher concentrations (250 mg L-1), biomass production was about 11 times lower than that of the substrate without NPs. Increased protein and sugar contents of the biofilm matrix corroborated the stimulating effects of low concentrations of ZnO NPs. Physiological data were supported by changes in the expression of genes associated with oxidative stress and biofilm development. ZnO NPs at 0.5 mg L-1 stimulated the expression of quorum sensing, lipopolysaccharide biosynthesis, and antibiotic resistance genes; high concentrations of ZnO NPs (250 mg L-1) down-regulated biofilm formation-related genes and up-regulated antioxidant genes. Our results indicate that long-term release of low concentrations of ZnO NPs to the environment would promote undesired biofilm formation and increased resistance to antibiotics.
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Affiliation(s)
- Kai Ouyang
- State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China; College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China
| | - Monika Mortimer
- Bren School of Environmental Science and Management, Earth Research Institute and University of California Center for the Environmental Implications of Nanotechnology (UC CEIN), University of California, Santa Barbara, CA 93106, United States
| | - Patricia A Holden
- Bren School of Environmental Science and Management, Earth Research Institute and University of California Center for the Environmental Implications of Nanotechnology (UC CEIN), University of California, Santa Barbara, CA 93106, United States
| | - Peng Cai
- State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
| | - Yichao Wu
- State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Chunhui Gao
- State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Qiaoyun Huang
- State Key Laboratory of Agricultural Microbiology, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
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Hegde S, Nilyanimit P, Kozlova E, Anderson ER, Narra HP, Sahni SK, Heinz E, Hughes GL. CRISPR/Cas9-mediated gene deletion of the ompA gene in symbiotic Cedecea neteri impairs biofilm formation and reduces gut colonization of Aedes aegypti mosquitoes. PLoS Negl Trop Dis 2019; 13:e0007883. [PMID: 31790395 PMCID: PMC6907859 DOI: 10.1371/journal.pntd.0007883] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 12/12/2019] [Accepted: 10/26/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Symbiotic bacteria are pervasive in mosquitoes and their presence can influence many host phenotypes that affect vectoral capacity. While it is evident that environmental and host genetic factors contribute in shaping the microbiome of mosquitoes, we have a poor understanding regarding how bacterial genetics affects colonization of the mosquito gut. The CRISPR/Cas9 gene editing system is a powerful tool to alter bacterial genomes facilitating investigations into host-microbe interactions but has yet to be applied to insect symbionts. METHODOLOGY/PRINCIPAL FINDINGS To investigate the role of bacterial genetic factors in mosquito biology and in colonization of mosquitoes we used CRISPR/Cas9 gene editing system to mutate the outer membrane protein A (ompA) gene of a Cedecea neteri symbiont isolated from Aedes mosquitoes. The ompA mutant had an impaired ability to form biofilms and poorly infected Ae. aegypti when reared in a mono-association under gnotobiotic conditions. In adult mosquitoes, the mutant had a significantly reduced infection prevalence compared to the wild type or complement strains, while no differences in prevalence were seen in larvae, suggesting genetic factors are particularly important for adult gut colonization. We also used the CRISPR/Cas9 system to integrate genes (antibiotic resistance and fluorescent markers) into the symbionts genome and demonstrated that these genes were functional in vitro and in vivo. CONCLUSIONS/SIGNIFICANCE Our results shed insights into the role of ompA gene in host-microbe interactions in Ae. aegypti and confirm that CRISPR/Cas9 gene editing can be employed for genetic manipulation of non-model gut microbes. The ability to use this technology for site-specific integration of genes into the symbiont will facilitate the development of paratransgenic control strategies to interfere with arboviral pathogens such Chikungunya, dengue, Zika and Yellow fever viruses transmitted by Aedes mosquitoes.
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Affiliation(s)
- Shivanand Hegde
- Departments of Vector Biology and Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Pornjarim Nilyanimit
- Center of Excellence in Clinical Virology, Chulalongkorn University, Bangkok, Thailand
| | - Elena Kozlova
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Enyia R. Anderson
- Departments of Vector Biology and Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Hema P. Narra
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Sanjeev K. Sahni
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Eva Heinz
- Department of Vector Biology and Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Grant L. Hughes
- Departments of Vector Biology and Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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13
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QseC Signaling in the Outbreak O104:H4 Escherichia coli Strain Combines Multiple Factors during Infection. J Bacteriol 2019; 201:JB.00203-19. [PMID: 31235511 DOI: 10.1128/jb.00203-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 06/08/2019] [Indexed: 12/22/2022] Open
Abstract
Enteroaggregative Escherichia coli (EAEC) from the O104:H4 specific serotype caused a large outbreak of bloody diarrhea with some complicated cases of hemolytic-uremic syndrome (HUS) in Europe in 2011. The outbreak strain consisted in an EAEC capable to produce the Shiga toxin (Stx) subtype 2a, a characteristic from enterohemorrhagic E. coli QseBC two-component system detects AI-3/Epi/NE and mediates the chemical signaling between pathogen and mammalian host. This system coordinates a cascade of virulence genes expression in important human enteropathogens. The blocking of QseC of EAEC C227-11 (Stx+) strain by N-phenyl-4-{[(phenylamino) thioxomethyl]amino}-benzenesulfonamide (also known as LED209) in vivo demonstrated a lower efficiency of colonization. The periplasmic protein VisP, which is related to survival mechanisms in a colitis model of infection, bacterial membrane maintenance, and stress resistance, here presented high levels of expression during the initial infection within the host. Under acid stress conditions, visP expression levels were differentiated in an Stx-dependent way. Together, these results emphasize the important role of VisP and the histidine kinase sensor QseC in the C227-11 (Stx+) outbreak strain for the establishment of the infectious niche process in the C57BL/6 mouse model and of LED209 as a promising antivirulence drug strategy against these enteric pathogens.IMPORTANCE EAEC is a remarkable etiologic agent of acute and persistent diarrhea worldwide. The isolates harbor specific subsets of virulence genes and their pathogenesis needs to be better understood. Chemical signaling via histidine kinase sensor QseC has been shown as a potential target to elucidate the orchestration of the regulatory cascade of virulence factors.
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Haque S, Yadav DK, Bisht SC, Yadav N, Singh V, Dubey KK, Jawed A, Wahid M, Dar SA. Quorum sensing pathways in Gram-positive and -negative bacteria: potential of their interruption in abating drug resistance. J Chemother 2019; 31:161-187. [DOI: 10.1080/1120009x.2019.1599175] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Shafiul Haque
- Research and Scientific Studies Unit, College of Nursing and Allied Health Sciences, Jazan University, Jazan, Saudi Arabia
- Gene Expression Laboratory, Department of Biosciences, Faculty of Natural Sciences, Jamia Millia Islamia, New Delhi, India
| | - Dinesh K. Yadav
- Department of Botany, University of Allahabad, Allahabad, Uttar Pradesh, India
| | - Shekhar C. Bisht
- Department of Biotechnology, H.N.B Garhwal University, Srinagar, Uttarakhand, India
| | - Neelam Yadav
- Department of Botany, University of Allahabad, Allahabad, Uttar Pradesh, India
| | - Vineeta Singh
- Microbiology Division, CSIR-Central Drug Research Institute, Lucknow, Uttar Pradesh, India
| | - Kashyap Kumar Dubey
- Industrial Biotechnology Laboratory, University Institute of Engineering and Technology, M.D. University, Rohtak, Haryana, India
| | - Arshad Jawed
- Research and Scientific Studies Unit, College of Nursing and Allied Health Sciences, Jazan University, Jazan, Saudi Arabia
| | - Mohd Wahid
- Research and Scientific Studies Unit, College of Nursing and Allied Health Sciences, Jazan University, Jazan, Saudi Arabia
| | - Sajad Ahmad Dar
- Research and Scientific Studies Unit, College of Nursing and Allied Health Sciences, Jazan University, Jazan, Saudi Arabia
- Departments of Microbiology, University College of Medical Sciences (University of Delhi), Delhi, India
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15
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Ali F, Yao Z, Li W, Sun L, Lin W, Lin X. In-Silico Prediction and Modeling of the Quorum Sensing LuxS Protein and Inhibition of AI-2 Biosynthesis in Aeromonas hydrophila. Molecules 2018; 23:E2627. [PMID: 30322111 PMCID: PMC6222731 DOI: 10.3390/molecules23102627] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 10/10/2018] [Accepted: 10/10/2018] [Indexed: 02/07/2023] Open
Abstract
luxS is conserved in several bacterial species, including A. hydrophila, which causes infections in prawn, fish, and shrimp, and is consequently a great risk to the aquaculture industry and public health. luxS plays a critical role in the biosynthesis of the autoinducer-2 (AI-2), which performs wide-ranging functions in bacterial communication, and especially in quorum sensing (QS). The prediction of a 3D structure of the QS-associated LuxS protein is thus essential to better understand and control A. hydrophila pathogenecity. Here, we predicted the structure of A. hydrophila LuxS and characterized it structurally and functionally with in silico methods. The predicted structure of LuxS provides a framework to develop more complete structural and functional insights and will aid the mitigation of A. hydrophila infection, and the development of novel drugs to control infections. In addition to modeling, the suitable inhibitor was identified by high through put screening (HTS) against drug like subset of ZINC database and inhibitor ((-)-Dimethyl 2,3-O-isopropylidene-l-tartrate) molecule was selected based on the best drug score. Molecular docking studies were performed to find out the best binding affinity between LuxS homologous or predicted model of LuxS protein for the ligand selection. Remarkably, this inhibitor molecule establishes agreeable interfaces with amino acid residues LYS 23, VAL 35, ILE76, and SER 90, which are found to play an essential role in inhibition mechanism. These predictions were suggesting that the proposed inhibitor molecule may be considered as drug candidates against AI-2 biosynthesis of A. hydrophila. Therefore, (-)-Dimethyl 2,3-O-isopropylidene-l-tartrate inhibitor molecule was studied to confirm its potency of AI-2 biosynthesis inhibition. The results shows that the inhibitor molecule had a better efficacy in AI-2 inhibition at 40 μM concentration, which was further validated using Western blotting at a protein expression level. The AI-2 bioluminescence assay showed that the decreased amount of AI-2 biosynthesis and downregulation of LuxS protein play an important role in the AI-2 inhibition. Lastly, these experiments were conducted with the supplementation of antibiotics via cocktail therapy of AI-2 inhibitor plus OXY antibiotics, in order to determine the possibility of novel cocktail drug treatments of A. hydrophila infection.
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Affiliation(s)
- Farman Ali
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 35002, China.
- Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University) Fujian Province University, Fuzhou 35002, China.
| | - Zujie Yao
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 35002, China.
- Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University) Fujian Province University, Fuzhou 35002, China.
| | - Wanxin Li
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 35002, China.
- Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University) Fujian Province University, Fuzhou 35002, China.
| | - Lina Sun
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 35002, China.
- Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University) Fujian Province University, Fuzhou 35002, China.
| | - Wenxiong Lin
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 35002, China.
- Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University) Fujian Province University, Fuzhou 35002, China.
| | - Xiangmin Lin
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 35002, China.
- Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University) Fujian Province University, Fuzhou 35002, China.
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16
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Ji Y, Li W, Zhang Y, Chen L, Zhang Y, Zheng X, Huang X, Ni B. QseB mediates biofilm formation and invasion in Salmonella enterica serovar Typhi. Microb Pathog 2017; 104:6-11. [DOI: 10.1016/j.micpath.2017.01.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 12/23/2016] [Accepted: 01/02/2017] [Indexed: 10/24/2022]
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17
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Talagrand-Reboul E, Jumas-Bilak E, Lamy B. The Social Life of Aeromonas through Biofilm and Quorum Sensing Systems. Front Microbiol 2017; 8:37. [PMID: 28163702 PMCID: PMC5247445 DOI: 10.3389/fmicb.2017.00037] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 01/06/2017] [Indexed: 01/25/2023] Open
Abstract
Bacteria of the genus Aeromonas display multicellular behaviors herein referred to as “social life”. Since the 1990s, interest has grown in cell-to-cell communication through quorum sensing signals and biofilm formation. As they are interconnected, these two self-organizing systems deserve to be considered together for a fresh perspective on the natural history and lifestyles of aeromonads. In this review, we focus on the multicellular behaviors of Aeromonas, i.e., its social life. First, we review and discuss the available knowledge at the molecular and cellular levels for biofilm and quorum sensing. We then discuss the complex, subtle, and nested interconnections between the two systems. Finally, we focus on the aeromonad multicellular coordinated behaviors involved in heterotrophy and virulence that represent technological opportunities and applied research challenges.
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Affiliation(s)
- Emilie Talagrand-Reboul
- Équipe Pathogènes Hydriques Santé Environnements, UMR 5569 HSM, Université de MontpellierMontpellier, France; Département d'Hygiène Hospitalière, Centre Hospitalier Régional Universitaire (CHRU) de MontpellierMontpellier, France
| | - Estelle Jumas-Bilak
- Équipe Pathogènes Hydriques Santé Environnements, UMR 5569 HSM, Université de MontpellierMontpellier, France; Département d'Hygiène Hospitalière, Centre Hospitalier Régional Universitaire (CHRU) de MontpellierMontpellier, France
| | - Brigitte Lamy
- Équipe Pathogènes Hydriques Santé Environnements, UMR 5569 HSM, Université de MontpellierMontpellier, France; Département de Bactériologie, Centre Hospitalier Universitaire (CHU) de NiceNice, France
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18
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Du H, Pang M, Dong Y, Wu Y, Wang N, Liu J, Awan F, Lu C, Liu Y. Identification and Characterization of an Aeromonas hydrophila Oligopeptidase Gene pepF Negatively Related to Biofilm Formation. Front Microbiol 2016; 7:1497. [PMID: 27713736 PMCID: PMC5032638 DOI: 10.3389/fmicb.2016.01497] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 09/07/2016] [Indexed: 01/02/2023] Open
Abstract
Bacterial biofilms are involved in adaptation to complex environments and are responsible for persistent bacterial infections. Biofilm formation is a highly complex process during which multifarious genes work together regularly. In this study, we screened the EZ-Tn5 transposon mutant library to identify genes involved in biofilm formation of Aeromonas hydrophila. A total of 24 biofilm-associated genes were identified, the majority of which encoded proteins related to cell structure, transcription and translation, gene regulation, growth and metabolism. The mutant strain TM90, in which a gene encoding oligopeptidase F (pepF) was disturbed, showed significant upregulation of biofilm formation compared to the parental strain. The TM90 colony phenotype was smaller, more transparent, and splendent. The adhesive ability of TM90 to HEp-2 cells was significantly increased compared with the parental strain. Fifty percent lethal dose (LD50) determinations in zebrafish demonstrated that the enhanced-biofilm mutant TM90 was highly attenuated relative to the wild-type strain. In conclusion, the pepF gene is demonstrated for the first time to be a negative factor for biofilm formation and is involved in A. hydrophila pathogenicity.
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Affiliation(s)
- Hechao Du
- College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Maoda Pang
- College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Yuhao Dong
- College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Yafeng Wu
- College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Nannan Wang
- College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Jin Liu
- College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Furqan Awan
- College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Chengping Lu
- College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
| | - Yongjie Liu
- College of Veterinary Medicine, Nanjing Agricultural University Nanjing, China
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Rasmussen-Ivey CR, Figueras MJ, McGarey D, Liles MR. Virulence Factors of Aeromonas hydrophila: In the Wake of Reclassification. Front Microbiol 2016; 7:1337. [PMID: 27610107 PMCID: PMC4997093 DOI: 10.3389/fmicb.2016.01337] [Citation(s) in RCA: 161] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 08/12/2016] [Indexed: 12/19/2022] Open
Abstract
The ubiquitous "jack-of-all-trades," Aeromonas hydrophila, is a freshwater, Gram-negative bacterial pathogen under revision in regard to its phylogenetic and functional affiliation with other aeromonads. While virulence factors are expectedly diverse across A. hydrophila strains and closely related species, our mechanistic knowledge of the vast majority of these factors is based on the molecular characterization of the strains A. hydrophila AH-3 and SSU, which were reclassified as A. piscicola AH-3 in 2009 and A. dhakensis SSU in 2013. Individually, these reclassifications raise important questions involving the applicability of previous research on A. hydrophila virulence mechanisms; however, this issue is exacerbated by a lack of genomic data on other research strains. Collectively, these changes represent a fundamental gap in the literature on A. hydrophila and confirm the necessity of biochemical, molecular, and morphological techniques in the classification of research strains that are used as a foundation for future research. This review revisits what is known about virulence in A. hydrophila and the feasibility of using comparative genomics in light of this phylogenetic revision. Conflicting data between virulence factors, secretion systems, quorum sensing, and their effect on A. hydrophila pathogenicity appears to be an artifact of inappropriate taxonomic comparisons and/or be due to the fact that these properties are strain-specific. This review audits emerging data on dominant virulence factors that are present in both A. dhakensis and A. hydrophila in order to synthesize existing data with the aim of locating where future research is needed.
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Affiliation(s)
| | - Maria J Figueras
- Departamento de Ciencias Médicas Básicas, Facultad de Medicina y Ciencias de la Salud, Institut d'Investigació Sanitària Pere Virgili, Universidad Rovira i Virgili, Reus Spain
| | - Donald McGarey
- Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, GA USA
| | - Mark R Liles
- Department of Biological Sciences, Auburn University, Auburn, AL USA
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20
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Chu W, McLean RJC. Quorum Signal Inhibitors and Their Potential Use against Fish Diseases. JOURNAL OF AQUATIC ANIMAL HEALTH 2016; 28:91-96. [PMID: 27184419 DOI: 10.1080/08997659.2016.1150907] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Quorum sensing (QS) is a process of bacterial communication used to control group behaviors, including bioluminescence, virulence factor production, biofilm formation, and biofilm antimicrobial tolerance. Many aquatic bacterial pathogens such as Aeromonas, Vibrio, and Edwardsiella spp. use QS to regulate virulence factor production. The disruption of QS has been shown to be an effective strategy in the competition between higher organisms and bacteria and more recently between bacterial species. For this reason, QS disruption has been proposed as a strategy to prevent bacterial pathogenicity. In this review, we summarize the current literature and illustrate the value of QS inhibitors in controlling virulence production in aquatic bacterial pathogens. This represents a new, nonantibiotic strategy to combat fish diseases. Received August 11, 2015; accepted January 26, 2016.
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Affiliation(s)
- Weihua Chu
- a Department of Microbiology , School of Life Science and Technology, China Pharmaceutical University , Nanjing 210009 , China
| | - Robert J C McLean
- b Department of Biology , Texas State University , 601 University Drive, San Marcos , Texas 78666 , USA
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21
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Chen PL, Lamy B, Ko WC. Aeromonas dhakensis, an Increasingly Recognized Human Pathogen. Front Microbiol 2016; 7:793. [PMID: 27303382 PMCID: PMC4882333 DOI: 10.3389/fmicb.2016.00793] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 05/11/2016] [Indexed: 12/18/2022] Open
Abstract
Aeromonas dhakensis was first isolated from children with diarrhea in Dhaka, Bangladesh and described in 2002. In the past decade, increasing evidence indicate this species is widely distributed in the environment and can cause a variety of infections both in human and animals, especially in coastal areas. A. dhakensis is often misidentified as A. hydrophila, A. veronii, or A. caviae by commercial phenotypic tests in the clinical laboratory. Correct identification relies on molecular methods. Increasingly used matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) may be able to identify Aeromonas specie rapidly and accurately. A. dhakensis has shown its potent virulence in different animal models and clinical infections. Although several virulence factors had been reported, no single mechanism is conclusive. Characteristically A. dhakensis is the principal species causing soft tissue infection and bacteremia, especially among patients with liver cirrhosis or malignancy. Of note, A. dhakensis bacteremia is more lethal than bacteremia due to other Aeromonas species. The role of this species in gastroenteritis remains controversial. Third generation cephalosporins and carbapenems should be used cautiously in the treatment of severe A. dhakensis infection due to the presence of AmpC ββ-lactamase and metallo-β-lactamase genes, and optimal regimens may be cefepime or fluoroquinolones. Studies of bacterial virulence factors and associated host responses may provide the chance to understand the heterogeneous virulence between species. The hypothesis A. dhakensis with varied geographic prevalence and enhanced virulence that compared to other Aeromonas species warrants more investigations.
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Affiliation(s)
- Po-Lin Chen
- Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung UniversityTainan, Taiwan; Center for Infection Control, National Cheng Kung University HospitalTainan, Taiwan
| | - Brigitte Lamy
- Laboratoire de Bactériologie-Virologie, Équipe Pathogènes Hydriques Santé Environnements, UMR 5569 HydroSciences Montpellier, Université de MontpellierMontpellier, France; Laboratoire de Bactériologie, Centre Hospitalier Régional Universitaire de MontpellierMontpellier, France
| | - Wen-Chien Ko
- Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung UniversityTainan, Taiwan; Center for Infection Control, National Cheng Kung University HospitalTainan, Taiwan
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Abstract
Chemical signaling between cells is an effective way to coordinate behavior within a community. Although cell-to-cell signaling has mostly been studied in single species, it is now appreciated that the sensing of chemical signals across kingdoms can be an important regulator of nutrient acquisition, virulence, and host defense. In this review, we focus on the role of interkingdom signaling in the interactions that occur between bacterial pathogens and their mammalian hosts. We discuss the quorum-sensing (QS) systems and other mechanisms used by these bacteria to sense, respond to, and modulate host signals that include hormones, immune factors, and nutrients. We also describe cross talk between these signaling pathways and strategies used by the host to interfere with bacterial signaling, highlighting the complex bidirectional signaling networks that are established across kingdoms.
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de Melo WCMA, Avci P, de Oliveira MN, Gupta A, Vecchio D, Sadasivam M, Chandran R, Huang YY, Yin R, Perussi LR, Tegos GP, Perussi JR, Dai T, Hamblin MR. Photodynamic inactivation of biofilm: taking a lightly colored approach to stubborn infection. Expert Rev Anti Infect Ther 2014; 11:669-93. [PMID: 23879608 DOI: 10.1586/14787210.2013.811861] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Microbial biofilms are responsible for a variety of microbial infections in different parts of the body, such as urinary tract infections, catheter infections, middle-ear infections, gingivitis, caries, periodontitis, orthopedic implants, and so on. The microbial biofilm cells have properties and gene expression patterns distinct from planktonic cells, including phenotypic variations in enzymic activity, cell wall composition and surface structure, which increase the resistance to antibiotics and other antimicrobial treatments. There is consequently an urgent need for new approaches to attack biofilm-associated microorganisms, and antimicrobial photodynamic therapy (aPDT) may be a promising candidate. aPDT involves the combination of a nontoxic dye and low-intensity visible light which, in the presence of oxygen, produces cytotoxic reactive oxygen species. It has been demonstrated that many biofilms are susceptible to aPDT, particularly in dental disease. This review will focus on aspects of aPDT that are designed to increase efficiency against biofilms modalities to enhance penetration of photosensitizer into biofilm, and a combination of aPDT with biofilm-disrupting agents.
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Affiliation(s)
- Wanessa C M A de Melo
- The Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA
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Escherichia coli O157:H7 lacking the qseBC-encoded quorum-sensing system outcompetes the parental strain in colonization of cattle intestines. Appl Environ Microbiol 2014; 80:1882-92. [PMID: 24413602 DOI: 10.1128/aem.03198-13] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The qseBC-encoded quorum-sensing system regulates the motility of Escherichia coli O157:H7 in response to bacterial autoinducer 3 (AI-3) and the mammalian stress hormones epinephrine (E) and norepinephrine (NE). The qseC gene encodes a sensory kinase that autophosphorylates in response to AI-3, E, or NE and subsequently phosphorylates its cognate response regulator QseB. In the absence of QseC, QseB downregulates bacterial motility and virulence in animal models. In this study, we found that 8- to 10-month-old calves orally inoculated with a mixture of E. coli O157:H7 and its isogenic qseBC mutant showed significantly higher fecal shedding of the qseBC mutant. In vitro analysis revealed similar growth profiles and motilities of the qseBC mutant and the parental strain in the presence or absence of NE. The magnitudes of the response to NE and expression of flagellar genes flhD and fliC were also similar for the qseBC mutant and the parental strain. The expression of ler (a positive regulator of the locus of enterocyte effacement [LEE]), the ler-regulated espA gene, and the csgA gene (encoding curli fimbriae) was increased in the qseBC mutant compared to the parental strain. On the other hand, growth, motility, and transcription of flhD, fliC, ler, espA, and csgA were significantly reduced in the qseBC mutant complemented with a plasmid-cloned copy of the qseBC genes. Thus, in vitro motility and gene expression data indicate that the near-parental level of motility, ability to respond to NE, and enhanced expression of LEE and curli genes might in part be responsible for increased colonization and fecal shedding of the qseBC mutant in calves.
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Abstract
Aeromonas species are inhabitants of aquatic environments and are able to cause disease in humans and fish among other animals. In aquaculture, they are responsible for the economically important diseases of furunculosis and motile Aeromonas septicaemia (MAS). Whereas gastroenteritis and wound infections are the major human diseases associated with the genus. As they inhabit and survive in diverse environments, aeromonads possess a wide range of colonisation factors. The motile species are able to swim in liquid environments through the action of a single polar flagellum, the flagellin subunits of which are glycosylated; although essential for function the biological role of glycan addition is yet to be determined. Approximately 60% of aeromonads possess a second lateral flagella system that is expressed in viscous environments for swarming over surfaces; both flagellar systems have been shown to be important in the initial colonisation of surfaces. Subsequently, other non-flagellar colonisation factors are employed; these can be both filamentous and non-filamentous. The aeromonads possess a number of fimbrial systems with the bundle-forming MSHA type IV pilus system, having a major role in human cell adherence. Furthermore, a series of outer-membrane proteins have also been implicated in the aeromonad adhesion process. A number of strains are also capable of cell invasion and that maybe linked with the more invasive diseases of bacteraemia or wound infections. These strains employ cell surface factors that allow the colonisation of these niches that protect them from the host's immune system such as S-layers, capsules or particular lipopolysaccharides.
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Affiliation(s)
- Rebecca Lowry
- Department of Infection and Immunity, University of Sheffield, Sheffield, United Kingdom
| | - Sabela Balboa
- Department of Infection and Immunity, University of Sheffield, Sheffield, United Kingdom; Departamento de Microbiología y Parasitología, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
| | - Jennifer L Parker
- Department of Infection and Immunity, University of Sheffield, Sheffield, United Kingdom
| | - Jonathan G Shaw
- Department of Infection and Immunity, University of Sheffield, Sheffield, United Kingdom.
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Gao X, Jian J, Li WJ, Yang YC, Shen XW, Sun ZR, Wu Q, Chen GQ. Genomic study of polyhydroxyalkanoates producing Aeromonas hydrophila 4AK4. Appl Microbiol Biotechnol 2013; 97:9099-109. [PMID: 24000047 DOI: 10.1007/s00253-013-5189-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 08/07/2013] [Accepted: 08/11/2013] [Indexed: 11/30/2022]
Abstract
The complete genome of Gram-negative Aeromonas hydrophila 4AK4 that has been used for industrial production of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) was sequenced and annotated. Its chromosome is 4,527,993 bp in size encoding 4,272 genes, including 28 rRNA genes and 104 tRNA genes. Comparative analysis indicated that genome of A. hydrophila 4AK4 was similar to that of the A. hydrophila ATCC 7966(T), an intensively studied aeromonad for its pathogenicity related to its genomic information. Genes possibly coming from other species or even other genus were identified in A. hydrophila 4AK4. A large number of putative virulent genes were predicted. However, a cytotonic enterotoxin (Ast) is absent in A. hydrophila 4AK4, allowing the industrial strain to be different from other A. hydrophila strains, indicating possible reduced virulence of strain 4AK4, which is very important for industrial fermentation. Genes involved in polyhydroxyalkanoate (PHA) metabolism were predicted and analyzed. The resulting genomic information is useful for improved production of PHA via metabolic engineering of A. hydrophila 4AK4.
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Affiliation(s)
- Xue Gao
- MOE Key Lab of Bioinformatics, School of Life Science, Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing, 100084, China
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Characterization of Aeromonas hydrophila wound pathotypes by comparative genomic and functional analyses of virulence genes. mBio 2013; 4:e00064-13. [PMID: 23611906 PMCID: PMC3638308 DOI: 10.1128/mbio.00064-13] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Aeromonas hydrophila has increasingly been implicated as a virulent and antibiotic-resistant etiologic agent in various human diseases. In a previously published case report, we described a subject with a polymicrobial wound infection that included a persistent and aggressive strain of A. hydrophila (E1), as well as a more antibiotic-resistant strain of A. hydrophila (E2). To better understand the differences between pathogenic and environmental strains of A. hydrophila, we conducted comparative genomic and functional analyses of virulence-associated genes of these two wound isolates (E1 and E2), the environmental type strain A. hydrophila ATCC 7966T, and four other isolates belonging to A. aquariorum, A. veronii, A. salmonicida, and A. caviae. Full-genome sequencing of strains E1 and E2 revealed extensive differences between the two and strain ATCC 7966T. The more persistent wound infection strain, E1, harbored coding sequences for a cytotoxic enterotoxin (Act), a type 3 secretion system (T3SS), flagella, hemolysins, and a homolog of exotoxin A found in Pseudomonas aeruginosa. Corresponding phenotypic analyses with A. hydrophila ATCC 7966T and SSU as reference strains demonstrated the functionality of these virulence genes, with strain E1 displaying enhanced swimming and swarming motility, lateral flagella on electron microscopy, the presence of T3SS effector AexU, and enhanced lethality in a mouse model of Aeromonas infection. By combining sequence-based analysis and functional assays, we characterized an A. hydrophila pathotype, exemplified by strain E1, that exhibited increased virulence in a mouse model of infection, likely because of encapsulation, enhanced motility, toxin secretion, and cellular toxicity. Aeromonas hydrophila is a common aquatic bacterium that has increasingly been implicated in serious human infections. While many determinants of virulence have been identified in Aeromonas, rapid identification of pathogenic versus nonpathogenic strains remains a challenge for this genus, as it is for other opportunistic pathogens. This paper demonstrates, by using whole-genome sequencing of clinical Aeromonas strains, followed by corresponding virulence assays, that comparative genomics can be used to identify a virulent subtype of A. hydrophila that is aggressive during human infection and more lethal in a mouse model of infection. This aggressive pathotype contained genes for toxin production, toxin secretion, and bacterial motility that likely enabled its pathogenicity. Our results highlight the potential of whole-genome sequencing to transform microbial diagnostics; with further advances in rapid sequencing and annotation, genomic analysis will be able to provide timely information on the identities and virulence potential of clinically isolated microorganisms.
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