Bacterial pili: molecular mechanisms of pathogenesis

Sauer, Frederic G.; Mulvey, Matthew; Schilling, Joel D.; Martínez, Juan José; Hultgren, Scott J.

doi:10.1016/s1369-5274(99)00053-3

Cited by 191 publications

(122 citation statements)

References 67 publications

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“…Pili and adherence. Attachment is a critical step in pathogenesis, and both pili and flagella are important virulence factors in many pathogenic bacteria (32,33). MSHA pilus (34), a type IV pilus (TFP), has been shown to play a role in adherence to plankton (38), the MSHA of V. mimicus may serve as a dual-function appendage, i. e., for intestinal adherence and attachment to plankton or other surfaces to form a biofilm.…”

Section: Resultsmentioning

confidence: 99%

Comparative genomics of clinical and environmental Vibrio mimicus

Hasan

Grim

Haley

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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Whether Vibrio mimicus is a variant of Vibrio cholerae or a separate species has been the subject of taxonomic controversy. A genomic analysis was undertaken to resolve the issue. The genomes of V. mimicus MB451, a clinical isolate, and VM223, an environmental isolate, comprise ca. 4,347,971 and 4,313,453 bp and encode 3,802 and 3,290 ORFs, respectively. As in other vibrios, chromosome I (C-I) predominantly contains genes necessary for growth and viability, whereas chromosome II (C-II) bears genes for adaptation to environmental change. C-I harbors many virulence genes, including some not previously reported in V. mimicus, such as mannose-sensitive hemagglutinin (MSHA), and enterotoxigenic hemolysin (HlyA); C-II encodes a variant of Vibrio pathogenicity island 2 (VPI-2), and Vibrio seventh pandemic island II (VSP-II) cluster of genes. Extensive genomic rearrangement in C-II indicates it is a hot spot for evolution and genesis of speciation for the genus Vibrio. The number of virulence regions discovered in this study (VSP-II, MSHA, HlyA, type IV pilin, PilE, and integron integrase, IntI4) with no notable difference in potential virulence genes between clinical and environmental strains suggests these genes also may play a role in the environment and that pathogenic strains may arise in the environment. Significant genome synteny with prototypic pre-seventh pandemic strains of V. cholerae was observed, and the results of phylogenetic analysis support the hypothesis that, in the course of evolution, V. mimicus and V. cholerae diverged from a common ancestor with a prototypic sixth pandemic genomic backbone.A Gram-negative gamma Proteobacterium, Vibrio mimicus is closely related to Vibrio cholerae. It was first described as a biochemically atypical Vibrio cholerae (1). However, it is phenotypically and genotypically distinct from V. cholerae and can be differentiated from V. cholerae by 12 specific biochemical reactions, including sucrose fermentation, Voges-Proskauer reaction (acetoin production from glucose), lipase production, sodium tartrate fermentation, and polymyxin sensitivity. showed mean pairwise divergence from V. cholerae to be ≈10%, equivalent to the divergence of Salmonella enterica LT2 from Escherichia coli K-12 (2, 3).The natural habitat of V. mimicus is similar to that of V. cholerae, i.e., the aquatic ecosystem, including seawater, freshwater, and brackish water, where it has been found both as a free-living bacterium and in association with zooplankton, crustaceans, filter-feeding mollusks, turtle eggs, and fish. Infections in humans occur from consumption or exposure to these sources (4-9). V. mimicus human gastroenteritis is characterized by diarrhea, nausea, vomiting, abdominal cramps, and fever. However, unlike V. cholerae, V. mimicus has not been associated with epidemics of cholera-like diarrhea, probably because most isolates of V. mimicus do not produce cholera toxin (CT). In fact, Chowdhury et al. (5) reported that fewer than 10% of clinical isolates and fewer than 1% of environmental st...

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Section: Resultsmentioning

confidence: 99%

Comparative genomics of clinical and environmental Vibrio mimicus

Hasan

Grim

Haley

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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“…Pili are helical filaments that mediate attachment to specific surfaces, e.g. host tissue (Fernandéz & Berenguer, 2000;Sauer et al, 2000). In addition, the EHOS has presumably also lost or altered some membrane proteins, possibly gaining a selective advantage via reduced immune recognition.…”

Section: Discussionmentioning

confidence: 99%

Identification of resistance and virulence factors in an epidemic Enterobacter hormaechei outbreak strain

Paauw

Caspers²,

Hall

et al. 2009

Microbiology

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Bacterial strains differ in their ability to cause hospital outbreaks. Using comparative genomic hybridization, Enterobacter cloacae complex isolates were studied to identify genetic markers specific for Enterobacter cloacae complex outbreak strains. No outbreak-specific genes were found that were common in all investigated outbreak strains. Therefore, the aim of our study was to identify specific genetic markers for an Enterobacter hormaechei outbreak strain (EHOS) that caused a nationwide outbreak in The Netherlands. Most EHOS isolates carried a large conjugative plasmid (pQC) containing genes encoding heavy-metal resistance, mobile elements, pili-associated proteins and exported proteins as well as multiple-resistance genes. Furthermore, the chromosomally encoded high-pathogenicity island (HPI) was highly associated with the EHOS strain. In addition, other DNA fragments were identified that were associated with virulence: three DNA fragments known to be located on a virulence plasmid (pLVPK), as well as phage-and plasmid-related sequences. Also, four DNA fragments encoding putative pili with the most homology to pili of Salmonella enterica were associated with the EHOS. Finally, four DNA fragments encoding putative outer-membrane proteins were negatively associated with the EHOS. In conclusion, resistance and putative virulence genes were identified in the EHOS that may have contributed to increased epidemicity. The high number of genes detected in the EHOS that were related to transferable elements reflects the genomic plasticity of the E. cloacae complex and may explain the emergence of the EHOS in the hospital environment. INTRODUCTIONIn the pre-antibiotic era, isolates of the Enterobacter cloacae complex were not detected in surveys of nosocomial bacteria; they were first described as nosocomial pathogens in the 1970s (Sanders & Sanders, 1997). In 2001, Enterobacter spp. caused 7 % of nosocomial infections in intensive care units in the USA (Jones, 2003;Streit et al., 2004). Therefore, the E. cloacae complex can be considered as an emerging pathogen, of which Enterobacter hormaechei is the most commonly isolated nosocomial pathogen (Delmas et al., 2006;Paauw et al., 2008). A nationwide outbreak occurred with an E. hormaechei outbreak strain (EHOS) in The Netherlands . This strain disseminated throughout hospitals despite adequate implementation of internationally accepted infection-prevention guidelines and caused invasive infections in more than 100 patients (Paauw et al., 2007). Previous studies showed that most EHOS isolates carried the conjugative plasmid pQC, with several complex integrons containing aadB, bla CTX-M-9 and qnrA1 genes that encoded resistance to aminoglycosides and thirdgeneration cephalosporins, and reduced susceptibility to fluoroquinolones, respectively . However, it was also shown that other Enterobacteriaceae including other E. cloacae complex isolates with the pQC did not become highly epidemic like the EHOS (Paauw et al., 2007). Furthermore, of aminoglycoside-susceptible E. cloa...

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“…Statistical analysis of COGs in the swine metagenomes showed that genes encoding virulence, gene-transfer, and energy production and conversion functions are selected by in-feed antibiotics. Specifically overrepresented COGs included some relating to P pilus assembly; the P pilus has been described for attachment and virulence in E. coli (31). Additional COGs of interest in the medicated metagenome included transposases, which are known to participate in the transfer of antibiotic resistance genes (32).…”

Section: Tetb(p) Tet(q) Tetracyclinementioning

confidence: 99%

In-feed antibiotic effects on the swine intestinal microbiome

Looft

Johnson

Allen³

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

913

661

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Antibiotics have been administered to agricultural animals for disease treatment, disease prevention, and growth promotion for over 50 y. The impact of such antibiotic use on the treatment of human diseases is hotly debated. We raised pigs in a highly controlled environment, with one portion of the littermates receiving a diet containing performance-enhancing antibiotics [chlortetracycline, sulfamethazine, and penicillin (known as ASP250)] and the other portion receiving the same diet but without the antibiotics. We used phylogenetic, metagenomic, and quantitative PCR-based approaches to address the impact of antibiotics on the swine gut microbiota. Bacterial phylotypes shifted after 14 d of antibiotic treatment, with the medicated pigs showing an increase in Proteobacteria (1-11%) compared with nonmedicated pigs at the same time point. This shift was driven by an increase in Escherichia coli populations. Analysis of the metagenomes showed that microbial functional genes relating to energy production and conversion were increased in the antibiotic-fed pigs. The results also indicate that antibiotic resistance genes increased in abundance and diversity in the medicated swine microbiome despite a high background of resistance genes in nonmedicated swine. Some enriched genes, such as aminoglycoside O-phosphotransferases, confer resistance to antibiotics that were not administered in this study, demonstrating the potential for indirect selection of resistance to classes of antibiotics not fed. The collateral effects of feeding subtherapeutic doses of antibiotics to agricultural animals are apparent and must be considered in cost-benefit analyses.intestinal microbiota | microbiome shifts | swine bacteria | BioTrove microarray | metagenomics

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Bacterial pili: molecular mechanisms of pathogenesis

Cited by 191 publications

References 67 publications

Comparative genomics of clinical and environmental Vibrio mimicus

Comparative genomics of clinical and environmental Vibrio mimicus

Identification of resistance and virulence factors in an epidemic Enterobacter hormaechei outbreak strain

In-feed antibiotic effects on the swine intestinal microbiome

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