Bacteriophage-Encoding Cytolethal Distending Toxin Type V Gene Induced from Nonclinical Escherichia coli Isolates

ABSTRACTCytolethal distending toxin (Cdt) is produced by a variety of pathogenic bacteria, including pathogenic serotypes of Shiga toxin-producingEscherichia coli(STEC). The Cdt family comprises five variants (Cdt-I to Cdt-V) encoded by three genes located within the chromosome or plasmids or, in the case of Cdt-I, within bacteriophages. In this study, we evaluated the occurrence of thecdtgene in a collection of 140 environmental STEC isolates.cdtwas detected in 12.1% of strains, of which five strains carried inducible bacteriophages containing the Cdt-V variant. Two Cdt-V phages of theSiphoviridaemorphology lysogenizedShigella sonnei, generating two lysogens: a single Cdt phage lysogen and a double lysogen, containing a Cdt phage and an Stx phage, both from the wild-type strain. The rates of induction of Cdt phages were evaluated by quantitative PCR, and spontaneous induction of Cdt-V phage was observed, whereas induction of Stx phage in the double lysogen was mitomycin C dependent. The Cdt distending effect was observed in HeLa cells inoculated with the supernatant of the Cdt-V phage lysogen. A ClaI fragment containing thecdt-Vgene of one phage was cloned, and sequencing confirmed the presence of Cdt-V, as well as a fragment downstream from thecdthomolog togpA, encoding a replication protein of bacteriophage P2. Evaluation of Cdt-V phages in nonclinical water samples showed densities of 102to 109gene copies in 100 ml, suggesting the high prevalence of Cdt phages in nonclinical environments.

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Emergence and Comparative Genomics Analysis of Extended-Spectrum-β-Lactamase-Producing Escherichia coli Carrying mcr-1 in Fennec Fox Imported from Sudan to China

mSphere ◽

10.1128/msphere.00732-19 ◽

2019 ◽

Vol 4 (6) ◽

Cited By ~ 1

Author(s):

Chunyan Feng ◽

Peipei Wen ◽

Hao Xu ◽

Xiaohui Chi ◽

Shuang Li ◽

...

Keyword(s):

Escherichia Coli ◽

Pathogenic Bacteria ◽

Southern Blotting ◽

Wild Animals ◽

Content Type ◽

E Coli ◽

Extended Spectrum ◽

Broth Microdilution Method ◽

High Prevalence ◽

Esbl Producers

ABSTRACT The aim of this study was to investigate the occurrence and genomic characteristics of extended-spectrum-β-lactamase-producing Escherichia coli (ESBL-EC) in fennec fox imported from Sudan to China. We screened 88 fecal samples from fennec fox for ESBL-EC, using cefotaxime- and meropenem-supplemented selective medium. Antimicrobial susceptibility testing was performed by the agar dilution method except for colistin and tigecycline; for colistin and tigecycline, testing was conducted by the broth microdilution method. ESBL-EC bacteria were sequenced, and their genomes were characterized. Plasmid conjugation, S1 nuclease pulsed-field gel electrophoresis (PFGE), and Southern blotting were performed for a MCR-1-producing isolate. The genetic environment of mcr-1 and ESBL genes was also investigated. A total of 29 ESBL-EC bacteria were isolated from 88 fennec fox (32.9%), while no carbapenemase producers were found. The most prevalent genotypes were the blaCTX-M-55 and blaCTX-M-14 genes, followed by blaCTX-M-15 and blaCTX-M-64. We detected nine sequence types among 29 ESBL-EC. Furthermore, the mcr-1 gene was detected in isolate EcFF273. Conjugation analysis confirmed that the mcr-1 gene was transferable. S1 PFGE, Southern blotting, and whole-genome sequencing revealed that mcr-1 and blaCTX-M-64 were both located on a 65-kb IncI2 plasmid. This study reports for the first time the occurrence of ESBL-EC in fennec fox. The high prevalence of ESBL producers and the occurrence of MCR-1 producer in fennec fox imported into China from Sudan are unexpected. In addition, it clearly demonstrated that commensal E. coli strains can be reservoirs of blaCTX-M and mcr-1, potentially contributing to the dissemination and transfer of such genes to pathogenic bacteria among fennec fox. Our results support the implication of fennec fox as a biological vector for ESBL-producing members of the Enterobacteriaceae family. IMPORTANCE The extended-spectrum-β-lactamase (ESBL)-producing members of the Enterobacteriaceae family are a global concern for both animal and human health. There is some information indicating a high prevalence of ESBL producers in food animals. Moreover, there have been an increasing number of reports on ESBL-producing strains resistant to the last-resort antibiotic colistin with the global dissemination of the plasmid-mediated mcr-1 gene, which is believed to have originated in animal breeding. However, little is known regarding the burden of ESBL-producing Enterobacteriaceae on wild animals. No data were available on the prevalence of antimicrobial resistance (AMR) among wild animals imported into China. This is the first study to investigate the microbiological and genomics surveillance investigation of ESBL colonization among fennec fox (Vulpes zerda) imported from Sudan to China, and we uncovered a high prevalence of ESBL-EC. Furthermore, the underlying mechanism of colistin resistance in an isolate that harbored mcr-1 was also investigated. Results of characterization and analysis of 29 ESBL-producing E. coli may have important implications on our understanding of the transmission dynamics of these bacteria. We emphasize the importance of improved multisectoral surveillance for colistin-resistant E. coli in this region.

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d-Serine induces distinct transcriptomes in diverse Escherichia coli pathotypes

Microbiology ◽

10.1099/mic.0.001093 ◽

2021 ◽

Vol 167 (10) ◽

Author(s):

James P. R. Connolly ◽

Natasha C. A. Turner ◽

Jennifer C. Hallam ◽

Patricia T. Rimbi ◽

Tom Flett ◽

...

Keyword(s):

Escherichia Coli ◽

Type Species ◽

Pathogenic Bacteria ◽

Neonatal Meningitis ◽

Published Data ◽

Toxic Metabolite ◽

Transcriptional Responses ◽

Content Type ◽

E Coli ◽

Link Type

Appropriate interpretation of environmental signals facilitates niche specificity in pathogenic bacteria. However, the responses of niche-specific pathogens to common host signals are poorly understood. d-Serine (d-ser) is a toxic metabolite present in highly variable concentrations at different colonization sites within the human host that we previously found is capable of inducing changes in gene expression. In this study, we made the striking observation that the global transcriptional response of three Escherichia coli pathotypes – enterohaemorrhagic E. coli (EHEC), uropathogenic E. coli (UPEC) and neonatal meningitis-associated E. coli (NMEC) – to d-ser was highly distinct. In fact, we identified no single differentially expressed gene common to all three strains. We observed the induction of ribosome-associated genes in extraintestinal pathogens UPEC and NMEC only, and the induction of purine metabolism genes in gut-restricted EHEC, and UPEC indicating distinct transcriptional responses to a common signal. UPEC and NMEC encode dsdCXA – a genetic locus required for detoxification and hence normal growth in the presence of d-ser. Specific transcriptional responses were induced in strains accumulating d-ser (WT EHEC and UPEC/NMEC mutants lacking the d-ser-responsive transcriptional activator DsdC), corroborating the notion that d-ser is an unfavourable metabolite if not metabolized. Importantly, many of the UPEC-associated transcriptome alterations correlate with published data on the urinary transcriptome, supporting the hypothesis that d-ser sensing forms a key part of urinary niche adaptation in this pathotype. Collectively, our results demonstrate distinct pleiotropic responses to a common metabolite in diverse E. coli pathotypes, with important implications for niche selectivity.

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Identification and Regulation of a Novel Citrobacter rodentium Gut Colonization Fimbria (Gcf)

Journal of Bacteriology ◽

10.1128/jb.02486-14 ◽

2015 ◽

Vol 197 (8) ◽

pp. 1478-1491 ◽

Cited By ~ 2

Author(s):

Gustavo G. Caballero-Flores ◽

Matthew A. Croxen ◽

Verónica I. Martínez-Santos ◽

B. Brett Finlay ◽

José L. Puente

Keyword(s):

Escherichia Coli ◽

Intestinal Epithelium ◽

Pathogenic Bacteria ◽

Critical Role ◽

Growth Conditions ◽

Citrobacter Rodentium ◽

Content Type ◽

Gut Colonization ◽

Successful Infection

ABSTRACTThe Gram-negative enteric bacteriumCitrobacter rodentiumis a natural mouse pathogen that has been extensively used as a surrogate model for studying the human pathogens enteropathogenic and enterohemorrhagicEscherichia coli. All three pathogens produce similar attaching and effacing (A/E) lesions in the intestinal epithelium. During infection, these bacteria employ surface structures called fimbriae to adhere and colonize the host intestinal epithelium. ForC. rodentium, the roles of only a small number of its genome-carried fimbrial operons have been evaluated. Here, we report the identification of a novelC. rodentiumcolonization factor, calledgutcolonizationfimbria (Gcf), which is encoded by a chaperone-usher fimbrial operon. AgcfAmutant shows a severe colonization defect within the first 10 days of infection. Thegcfpromoter is not active inC. rodentiumunder severalin vitrogrowth conditions; however, it is readily expressed in aC. rodentiumΔhns1mutant lacking the closest ortholog of theEscherichia colihistone-like nucleoid structuring protein (H-NS) but not in mutants with deletion of the other four genes encoding H-NS homologs. H-NS binds to the regulatory region ofgcf, further supporting its direct role as a repressor of thegcfpromoter that starts transcription 158 bp upstream of the start codon of its first open reading frame. Thegcfoperon possesses interesting novel traits that open future opportunities to expand our knowledge of the structure, regulation, and function during infection of these important bacterial structures.IMPORTANCEFimbriae are surface bacterial structures implicated in a variety of biological processes. Some have been shown to play a critical role during host colonization and thus in disease. Pathogenic bacteria possess the genetic information for an assortment of fimbriae, but their function and regulation and the interplay between them have not been studied in detail. This work provides new insights into the function and regulation of a novel fimbria called Gcf that is important for early establishment of a successful infection byC. rodentiumin mice, despite being poorly expressed underin vitrogrowth conditions. This discovery offers an opportunity to better understand the individual role and the regulatory mechanisms controlling the expression of specific fimbrial operons that are critical during infection.

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A Novel Method of Serum Resistance by Escherichia coli That Causes Urosepsis

mBio ◽

10.1128/mbio.00920-18 ◽

2018 ◽

Vol 9 (3) ◽

Cited By ~ 6

Author(s):

Carrie F. Coggon ◽

Andrew Jiang ◽

Kelvin G. K. Goh ◽

Ian R. Henderson ◽

Mark A. Schembri ◽

...

Keyword(s):

Escherichia Coli ◽

Urinary Tract ◽

Serum Resistance ◽

Gram Negative ◽

Content Type ◽

Bacterial Surface ◽

O Antigen ◽

High Prevalence ◽

Novel Method ◽

Inhibitory Antibodies

ABSTRACT Uropathogenic Escherichia coli (UPEC) is the most common cause of urinary tract infection, which in some patients can develop into life-threatening urosepsis. Serum resistance is a key virulence trait of strains that cause urosepsis. Recently, we identified a novel method of serum resistance in patients with Pseudomonas aeruginosa lung infections, where patients possessed antibodies that inhibited complement-mediated killing (instead of protecting against infection). These inhibitory antibodies were of the IgG2 subtype, specific to the O-antigen component of lipopolysaccharide (LPS) and coated the bacterial surface, preventing bacterial lysis by complement. As this mechanism could apply to any Gram-negative bacterial infection, we hypothesized that inhibitory antibodies may represent an uncharacterized mechanism of serum resistance in UPEC. To test this, 45 urosepsis patients with paired blood culture UPEC isolates were screened for serum titers of IgG2 specific for their cognate strain’s LPS. Eleven patients had sufficiently high titers of the antibody to inhibit serum-mediated killing of UPEC isolates by pooled healthy control sera. Depletion of IgG or removal of O-antigen restored sensitivity of the isolates to the cognate patient serum. Importantly, the isolates from these 11 patients were more sensitive to killing by serum than isolates from patients with no inhibitory antibodies. This suggests the presence of inhibitory antibodies may have allowed these strains to infect the bloodstream. The high prevalence of patients with inhibitory antibodies (24%) suggests that this phenomenon is an important mechanism of UPEC serum resistance. LPS-specific inhibitory antibodies have now been identified against three Gram-negative pathogens that cause disparate diseases. IMPORTANCE Despite improvements in the early detection and management of sepsis, morbidity and mortality are still high. Infections of the urinary tract are one of the most frequent sources of sepsis with Escherichia coli the main causative agent. Serum resistance is vital for bacteria to infect the bloodstream. Here we report a novel method of serum resistance found in patients with UPEC-mediated sepsis. Antibodies in sera usually protect against infection, but here we found that 24% of patients expressed “inhibitory antibodies” capable of preventing serum-mediated killing of their infecting isolate. Our data suggest that these antibodies would allow otherwise serum-sensitive UPEC strains to cause sepsis. The high prevalence of patients with inhibitory antibodies in this cohort suggests that this is a widespread mechanism of resistance to complement-mediated killing in urosepsis patients, invoking the potential for the application of new methods to prevent and treat sepsis.

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Bioinformatic and Molecular Analysis of Inverse Autotransporters from Escherichia coli

mSphere ◽

10.1128/msphere.00572-19 ◽

2019 ◽

Vol 4 (4) ◽

Cited By ~ 3

Author(s):

Kelvin G. K. Goh ◽

Danilo G. Moriel ◽

Steven J. Hancock ◽

Minh-Duy Phan ◽

Mark A. Schembri

Keyword(s):

Escherichia Coli ◽

Cell Surface ◽

Biofilm Formation ◽

Secretion System ◽

Content Type ◽

E Coli ◽

Wide Range ◽

Type V Secretion ◽

K 12 ◽

Type V

ABSTRACT Proteins secreted by the type V secretion system possess multiple functions, including the capacity to mediate adhesion, aggregation, and biolfilm formation. The type V secretion system can be divided into five subclasses, one of which is the type Ve system. Proteins of the type Ve secretion system are also referred to as inverse autotransporters (IATs). In this study, we performed an in silico analysis of 126 completely sequenced Escherichia coli genomes available in the NCBI database and identified several distinct IAT-encoding gene families whose distribution varied throughout the E. coli phylogeny. The genes included three characterized IATs (intimin, fdeC, and yeeJ) and four uncharacterized IATs (here named iatA, iatB, iatC, and iatD). The four iat genes were cloned from the completely sequenced environmental E. coli strain SMS-3-5 and characterized. Three of these IAT proteins (IatB, IatC, and IatD) were expressed at the cell surface and possessed the capacity to mediate biofilm formation in a recombinant E. coli K-12 strain. Further analysis of the iatB gene, which showed a unique association with extraintestinal E. coli strains, suggested that its regulation is controlled by the LeuO global regulator. Overall, this study provides new data describing the prevalence, sequence variation, domain structure, function, and regulation of IATs found in E. coli. IMPORTANCE Escherichia coli is one of the most prevalent facultative anaerobes of the human gut. E. coli normally exists as a harmless commensal but can also cause disease following the acquisition of genes that enhance its pathogenicity. Adhesion is an important first step in colonization of the host and is mediated by an array of cell surface components. In E. coli, these include a family of adhesins secreted by the type V secretion system. Here, we identified and characterized new proteins from an emerging subclass of the type V secretion system known as the inverse autotransporters (IATs). We found that IAT-encoding genes are present in a wide range of strains and showed that three novel IATs were localized on the E. coli cell surface and mediated biofilm formation. Overall, this study provides new insight into the prevalence, function, and regulation of IATs in E. coli.

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Unstable Mechanisms of Resistance to Inhibitors of Escherichia coli Lipoprotein Signal Peptidase

mBio ◽

10.1128/mbio.02018-20 ◽

2020 ◽

Vol 11 (5) ◽

Cited By ~ 1

Author(s):

Homer Pantua ◽

Elizabeth Skippington ◽

Marie-Gabrielle Braun ◽

Cameron L. Noland ◽

Jingyu Diao ◽

...

Keyword(s):

Escherichia Coli ◽

Antibiotic Susceptibility ◽

Pathogenic Bacteria ◽

Susceptibility Testing ◽

Regulatory Elements ◽

Signal Peptidase ◽

Type Ii ◽

Mechanisms Of Resistance ◽

Content Type ◽

E Coli

ABSTRACT Clinical development of antibiotics with novel mechanisms of action to kill pathogenic bacteria is challenging, in part, due to the inevitable emergence of resistance. A phenomenon of potential clinical importance that is broadly overlooked in preclinical development is heteroresistance, an often-unstable phenotype in which subpopulations of bacterial cells show decreased antibiotic susceptibility relative to the dominant population. Here, we describe a new globomycin analog, G0790, with potent activity against the Escherichia coli type II signal peptidase LspA and uncover two novel resistance mechanisms to G0790 in the clinical uropathogenic E. coli strain CFT073. Building on the previous finding that complete deletion of Lpp, the major Gram-negative outer membrane lipoprotein, leads to globomycin resistance, we also find that an unexpectedly modest decrease in Lpp levels mediated by insertion-based disruption of regulatory elements is sufficient to confer G0790 resistance and increase sensitivity to serum killing. In addition, we describe a heteroresistance phenotype mediated by genomic amplifications of lspA that result in increased LspA levels sufficient to overcome inhibition by G0790 in culture. These genomic amplifications are highly unstable and are lost after as few as two subcultures in the absence of G0790, which places amplification-containing resistant strains at high risk of being misclassified as susceptible by routine antimicrobial susceptibility testing. In summary, our study uncovers two vastly different mechanisms of resistance to LspA inhibitors in E. coli and emphasizes the importance of considering the potential impact of unstable and heterogenous phenotypes when developing antibiotics for clinical use. IMPORTANCE Despite increasing evidence suggesting that antibiotic heteroresistance can lead to treatment failure, the significance of this phenomena in the clinic is not well understood, because many clinical antibiotic susceptibility testing approaches lack the resolution needed to reliably classify heteroresistant strains. Here we present G0790, a new globomycin analog and potent inhibitor of the Escherichia coli type II signal peptidase LspA. We demonstrate that in addition to previously known mechanisms of resistance to LspA inhibitors, unstable genomic amplifications containing lspA can lead to modest yet biologically significant increases in LspA protein levels that confer a heteroresistance phenotype.

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Spanish Multicenter Study of the Epidemiology and Mechanisms of Amoxicillin-Clavulanate Resistance in Escherichia coli

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.06393-11 ◽

2012 ◽

Vol 56 (7) ◽

pp. 3576-3581 ◽

Cited By ~ 34

Author(s):

Adriana Ortega ◽

Jesús Oteo ◽

Maitane Aranzamendi-Zaldumbide ◽

Rosa M. Bartolomé ◽

Germán Bou ◽

...

Keyword(s):

Escherichia Coli ◽

Multicenter Study ◽

Resistance Mechanisms ◽

Mechanisms Of Resistance ◽

Prospective Multicenter Study ◽

Content Type ◽

E Coli ◽

High Prevalence ◽

Amoxicillin Clavulanate ◽

High Degree

ABSTRACTWe conducted a prospective multicenter study in Spain to characterize the mechanisms of resistance to amoxicillin-clavulanate (AMC) inEscherichia coli. Up to 44 AMC-resistantE. coliisolates (MIC ≥ 32/16 μg/ml) were collected at each of the seven participant hospitals. Resistance mechanisms were characterized by PCR and sequencing. Molecular epidemiology was studied by pulsed-field gel electrophoresis (PFGE) and by multilocus sequence typing. Overall AMC resistance was 9.3%. The resistance mechanisms detected in the 257 AMC-resistant isolates were OXA-1 production (26.1%), hyperproduction of penicillinase (22.6%), production of plasmidic AmpC (19.5%), hyperproduction of chromosomic AmpC (18.3%), and production of inhibitor-resistant TEM (IRT) (17.5%). The IRTs identified were TEM-40 (33.3%), TEM-30 (28.9%), TEM-33 (11.1%), TEM-32 (4.4%), TEM-34 (4.4%), TEM-35 (2.2%), TEM-54 (2.2%), TEM-76 (2.2%), TEM-79 (2.2%), and the new TEM-185 (8.8%). By PFGE, a high degree of genetic diversity was observed although two well-defined clusters were detected in the OXA-1-producing isolates: the C1 cluster consisting of 19 phylogroup A/sequence type 88 [ST88] isolates and the C2 cluster consisting of 19 phylogroup B2/ST131 isolates (16 of them producing CTX-M-15). Each of the clusters was detected in six different hospitals. In total, 21.8% of the isolates were serotype O25b/phylogroup B2 (O25b/B2). AMC resistance inE. coliis widespread in Spain at the hospital and community levels. A high prevalence of OXA-1 was found. Although resistant isolates were genetically diverse, clonality was linked to OXA-1-producing isolates of the STs 88 and 131. Dissemination of IRTs was frequent, and the epidemic O25b/B2/ST131 clone carried many different mechanisms of AMC resistance.

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Virulence Meets Metabolism: Cra and KdpE Gene Regulation in Enterohemorrhagic Escherichia coli

mBio ◽

10.1128/mbio.00280-12 ◽

2012 ◽

Vol 3 (5) ◽

Cited By ~ 77

Author(s):

Jacqueline W. Njoroge ◽

Y. Nguyen ◽

Meredith M. Curtis ◽

Cristiano G. Moreira ◽

Vanessa Sperandio

Keyword(s):

Escherichia Coli ◽

Gene Regulation ◽

Virulence Factors ◽

Energy Efficient ◽

Pathogenic Bacteria ◽

Bloody Diarrhea ◽

Enterohemorrhagic Escherichia Coli ◽

Content Type ◽

Virulence Traits ◽

Niche Adaptation

ABSTRACTGastrointestinal (GI) bacteria sense diverse environmental signals as cues for differential gene regulation and niche adaptation. Pathogens such as enterohemorrhagicEscherichia coli(EHEC), which causes bloody diarrhea, use these signals for the temporal and energy-efficient regulation of their virulence factors. One of the main virulence strategies employed by EHEC is the formation of attaching and effacing (AE) lesions on enterocytes. Most of the genes necessary for the formation of these lesions are grouped within a pathogenicity island, the locus of enterocyte effacement (LEE), whose expression requires the LEE-encoded regulator Ler. Here we show that growth of EHEC in glycolytic environments inhibits the expression oflerand consequently all other LEE genes. Conversely, growth within a gluconeogenic environment activates expression of these genes. This sugar-dependent regulation is achieved through two transcription factors: KdpE and Cra. Both Cra and KdpE directly bind to thelerpromoter, and Cra’s affinity to this promoter is catabolite dependent. Moreover, we show that the Cra and KdpE proteins interactin vitroand that KdpE’s ability to bind DNA is enhanced by the presence of Cra. Cra is important for AE lesion formation, and KdpE contributes to this Cra-dependent regulation. The deletion ofcraandkdpEresulted in the ablation of AE lesions. One of the many challenges that bacteria face within the GI tract is to successfully compete for carbon sources. Linking carbon metabolism to the precise coordination of virulence expression is a key step in the adaptation of pathogens to the GI environment.IMPORTANCEAn appropriate and prompt response to environmental cues is crucial for bacterial survival. Cra and KdpE are two proteins found in both nonpathogenic and pathogenic bacteria that regulate genes in response to differences in metabolite concentration. In this work, we show that, in the deadly pathogen enterohemorrhagicEscherichia coli(EHEC) O157:H7, which causes bloody diarrhea, these two proteins influence important virulence traits. We also propose that their control of one or more of these virulence traits is due to the direct interaction of the Cra and KdpE proteins with each other, as well as with their DNA targets. This work shows how EHEC coopts established mechanisms for sensing the metabolites and stress cues in the environment, to induce virulence factors in a temporal and energy-efficient manner, culminating in disease. Understanding how pathogens commandeer nonpathogenic systems can help us develop measures to control them.

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Yersinia pestisacrAB-tolCin Antibiotic Resistance and Virulence

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.05338-11 ◽

2011 ◽

Vol 56 (2) ◽

pp. 1120-1123 ◽

Cited By ~ 17

Author(s):

Ida M. Lister ◽

Connor Raftery ◽

Joan Mecsas ◽

Stuart B. Levy

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Yersinia Pestis ◽

Pathogenic Bacteria ◽

Efflux Pump ◽

Efflux Pump Inhibitor ◽

Content Type ◽

Increased Susceptibility

ABSTRACTThe efflux pump AcrAB is important in the antibiotic resistance and virulence of several pathogenic bacteria. We report that deletion of theYersinia pestisAcrAB-TolC homolog leads to increased susceptibility to diverse substrates, including, though unlike inEscherichia coli, the aminoglycosides. Neither is theY. pestispump affected by the efflux pump inhibitor phenylalanine-arginine beta-naphthylamide. In mouse plague models, pump deletion does not have a significant effect on tissue colonization.

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Genetic Analysis of the Role ofyfiRin the Ability of Escherichia coli CFT073 To Control Cellular Cyclic Dimeric GMP Levels and To Persist in the Urinary Tract

Infection and Immunity ◽

10.1128/iai.01396-12 ◽

2013 ◽

Vol 81 (9) ◽

pp. 3089-3098 ◽

Cited By ~ 20

Author(s):

Erica L. Raterman ◽

Daniel D. Shapiro ◽

Daniel J. Stevens ◽

Kevin J. Schwartz ◽

Rodney A. Welch

Keyword(s):

Escherichia Coli ◽

Urinary Tract ◽

Type Strain ◽

Wild Type Strain ◽

Wild Type ◽

Cellulose Production ◽

Content Type ◽

E Coli ◽

Successful Infection ◽

Tract Infections

ABSTRACTDuring urinary tract infections (UTIs), uropathogenicEscherichia colimust maintain a delicate balance between sessility and motility to achieve successful infection of both the bladder and kidneys. Previous studies showed that cyclic dimeric GMP (c-di-GMP) levels aid in the control of the transition between motile and nonmotile states inE. coli. TheyfiRNBlocus inE. coliCFT073 contains genes for YfiN, a diguanylate cyclase, and its activity regulators, YfiR and YfiB. Deletion ofyfiRyielded a mutant that was attenuated in both the bladder and the kidneys when tested in competition with the wild-type strain in the murine model of UTI. A doubleyfiRNmutant was not attenuated in the mouse model, suggesting that unregulated YfiN activity and likely increased cytoplasmic c-di-GMP levels cause a survival defect. Curli fimbriae and cellulose production were increased in theyfiRmutant. Expression ofyhjH, a gene encoding a proven phosphodiesterase, in CFT073 ΔyfiRsuppressed the overproduction of curli fimbriae and cellulose and further verified that deletion ofyfiRresults in c-di-GMP accumulation. Additional deletion ofcsgDandbcsA, genes necessary for curli fimbriae and cellulose production, respectively, returned colonization levels of theyfiRdeletion mutant to wild-type levels. Peroxide sensitivity assays and iron acquisition assays displayed no significant differences between theyfiRmutant and the wild-type strain. These results indicate that dysregulation of c-di-GMP production results in pleiotropic effects that disableE. coliin the urinary tract and implicate the c-di-GMP regulatory system as an important factor in the persistence of uropathogenicE. coli in vivo.

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