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Sample records for uropathogenic escherichia coli

  1. Draft Genome Sequence of Uropathogenic Escherichia coli Strain NB8

    PubMed Central

    Mi, Zu-huang; Wang, Chun-xin; Zhu, Jian-ming

    2016-01-01

    Escherichia coli NB8 is a clinical pyelonephritis isolate. Here, we report the draft genome sequence of uropathogenic E. coli NB8, which contains drug resistance genes encoding resistance to beta-lactams, aminoglycosides, quinolones, macrolides, colistin, sulfonamide-trimethoprim, and tetracycline. NB8 infects the kidney and bladder, making it an important tool for studying E. coli pathogenesis. PMID:27609920

  2. Draft Genome Sequence of Uropathogenic Escherichia coli Strain NB8.

    PubMed

    Weng, Xing-Bei; Mi, Zu-Huang; Wang, Chun-Xin; Zhu, Jian-Ming

    2016-01-01

    Escherichia coli NB8 is a clinical pyelonephritis isolate. Here, we report the draft genome sequence of uropathogenic E. coli NB8, which contains drug resistance genes encoding resistance to beta-lactams, aminoglycosides, quinolones, macrolides, colistin, sulfonamide-trimethoprim, and tetracycline. NB8 infects the kidney and bladder, making it an important tool for studying E. coli pathogenesis. PMID:27609920

  3. Uropathogenic Escherichia coli-Associated Exotoxins.

    PubMed

    Welch, Rodney A

    2016-06-01

    Escherichia coli are a common cause of infectious disease outside of the gastrointestinal tract. Several independently evolved E. coli clades are common causes of urinary tract and bloodstream infections. There is ample epidemiological and in vitro evidence that several different protein toxins common to many, but not all, of these strains are likely to aid the colonization and immune-evasion ability of these bacteria. This review discusses our current knowledge and areas of ignorance concerning the contribution of the hemolysin; cytotoxic-necrotizing factor-1; and the autotransporters, Sat, Pic, and Vat, to extraintestinal human disease. PMID:27337488

  4. Uropathogenic Escherichia coli-associated exotoxins

    PubMed Central

    Welch, Rodney A.

    2015-01-01

    Escherichia coli are a common cause of infectious disease outside of the gastrointestinal tract. Several independently evolved E. coli clades are common causes of urinary tract and blood stream infections. There is ample epidemiological and in vitro evidence that several different protein toxins common to many but not all of these strains are likely to aid the colonization and immune evasion ability of these bacteria. This review discusses our current knowledge and areas of ignorance concerning the contribution of the hemolysin, cytotoxic necrotizing factor-1 and the autotransporters, Sat, Pic and Vat to extraintestinal human disease. PMID:27337488

  5. Origin and Dissemination of Antimicrobial Resistance among Uropathogenic Escherichia coli.

    PubMed

    Nolan, Lisa K; Li, Ganwu; Logue, Catherine M

    2015-10-01

    Antimicrobial agents of various types have important bearing on the outcomes of microbial infections. These agents may be bacteriostatic or -cidal, exert their impact via various means, originate from a living organism or a laboratory, and appropriately be used in or on living tissue or not. Though the primary focus of this chapter is on resistance to the antimicrobial agents used to treat uropathogenic Escherichia coli (UPEC)-caused urinary tract infections (UTIs), some attention will be given to UPEC's resistance to silver-containing antiseptics, which may be incorporated into catheters to prevent foreign body-associated UTIs. PMID:26542043

  6. Biochemical characteristic of biofilm of uropathogenic Escherichia coli Dr(+) strains.

    PubMed

    Zalewska-Piątek, Beata; Wilkanowicz, Sabina; Bruździak, Piotr; Piątek, Rafał; Kur, Józef

    2013-07-19

    Urinary tract infections caused by Escherichia coli are very common health problem in the developed countries. The virulence of the uropathogenic E. coli Dr(+) IH11128 is determined by Dr fimbriae, which are homopolymeric structures composed of DraE subunits with the DraD protein capping the fiber. In this study, we have analyzed the structural and biochemical properties of biofilms developed by E. coli strains expressing Dr fimbriae with or without the DraD tip subunit and the surface-exposed DraD protein. We have also demonstrated that these E. coli strains form biofilms on an abiotic surface in a nutrient-dependent fashion. We present evidence that Dr fimbriae are necessary during the first stage of bacterial interaction with the abiotic surface. In addition, we reveal that the DraD alone is also sufficient for the initial surface attachment at an even higher level than Dr fimbriae and that chloramphenicol is able to reduce the normal attachment of the analyzed E. coli. The action of chloramphenicol also shows that protein synthesis is required for the early events of biofilm formation. Additionally, we have identified reduced exopolysaccharide coverage in E. coli that express only Dr fimbrial polyadhesins at the cell surface with or without the DraD capping subunit.

  7. Covert operations of uropathogenic Escherichia coli within the urinary tract.

    PubMed

    Bower, Jean M; Eto, Danelle S; Mulvey, Matthew A

    2005-01-01

    Entry into host cells is required for many bacterial pathogens to effectively disseminate within a host, avoid immune detection and cause disease. In recent years, many ostensibly extracellular bacteria have been shown to act as opportunistic intracellular pathogens. Among these are strains of uropathogenic Escherichia coli (UPEC), the primary causative agents of urinary tract infections (UTIs). UPEC are able to transiently invade, survive and multiply within the host cells and tissues constituting the urinary tract. Invasion of host cells by UPEC is promoted independently by distinct virulence factors, including cytotoxic necrotizing factor, Afa/Dr adhesins, and type 1 pili. Here we review the diverse mechanisms and consequences of host cell invasion by UPEC, focusing also on the impact of these processes on the persistence and recurrence of UTIs.

  8. Uropathogenic Escherichia coli Epigenetically Manipulate Host Cell Death Pathways.

    PubMed

    Zhang, Zhengguo; Wang, Ming; Eisel, Florian; Tchatalbachev, Svetlin; Chakraborty, Trinad; Meinhardt, Andreas; Bhushan, Sudhanshu

    2016-04-01

    Urinary tract infections caused by uropathogenic Escherichia coli (UPEC) pathovars belong to the most frequent infections in human. It is well established that UPEC can subvert innate immune responses, but the role of UPEC in interfering with host cell death pathways is not known. Here, we show that UPEC abrogates activation of the host cell prosurvival protein kinase B signaling pathway, which results in the activation of mammalian forkhead box O (FOXO) transcription factors. Although FOXOs were localized in the nucleus and showed increased DNA-binding activity, no change in the expression levels of FOXO target genes were observed. UPEC can suppress BIM expression induced by LY249002, which results in attenuation of caspase 3 activation and blockage of apoptosis. Mechanistically, BIM expression appears to be epigenetically silenced by a decrease in histone 4 acetylation at the BIM promoter site. Taken together, these results suggest that UPEC can epigenetically silence BIM expression, a molecular switch that prevents apoptosis.

  9. Covert Operations of Uropathogenic Escherichia coli within the Urinary Tract

    PubMed Central

    Bower, Jean M.; Eto, Danelle S.; Mulvey, Matthew A.

    2008-01-01

    Entry into host cells is required for many bacterial pathogens to effectively disseminate within a host, avoid immune detection and cause disease. In recent years, many ostensibly extracellular bacteria have been shown to act as opportunistic intracellular pathogens. Among these are strains of uropathogenic Escherichia coli (UPEC), the primary causative agents of urinary tract infections (UTIs). UPEC are able to transiently invade, survive and multiply within the host cells and tissues constituting the urinary tract. Invasion of host cells by UPEC is promoted independently by distinct virulence factors, including cytotoxic necrotizing factor, Afa/Dr adhesins, and type 1 pili. Here we review the diverse mechanisms and consequences of host cell invasion by UPEC, focusing also on the impact of these processes on the persistence and recurrence of UTIs. PMID:15569242

  10. Biofilm and fluoroquinolone resistance of canine Escherichia coli uropathogenic isolates

    PubMed Central

    2014-01-01

    Background Escherichia coli is the most common uropathogen involved in urinary tract infection (UTI). Virulence of strains may differ, and may be enhanced by antimicrobial resistance and biofilm formation, resulting in increased morbidity and recurrent infections. The aim of this study was to evaluate the in vitro biofilm forming capacity of E. coli isolates from dogs with UTI, by using fluorescent in situ hybridization, and its association with virulence genes and antimicrobial resistance. Findings The proportion of biofilm-producing isolates significantly increased with the length of incubation time (P < 0.05). Biofilm production was significantly associated with fluoroquinolone resistance at all incubation time points and was independent of the media used (P < 0.05). Biofilm production was not associated with cnf1, hly, pap and sfa genes (P > 0.05), but was significantly associated with afa, aer and the β-lactamase genes (P < 0.05). Conclusions To the best of our knowledge, this is the first report showing significant association between biofilm production and fluoroquinolone resistance in E. coli isolates from dogs with UTI. Biofilm formation may contribute to UTI treatment failure in dogs, through the development of bacterial reservoirs inside bladder cells, allowing them to overcome host immune defenses and to establish recurrent infections. PMID:25099929

  11. Subversion of Host Innate Immunity by Uropathogenic Escherichia coli.

    PubMed

    Olson, Patrick D; Hunstad, David A

    2016-01-04

    Uropathogenic Escherichia coli (UPEC) cause the majority of community-onset urinary tract infections (UTI) and represent a major etiologic agent of healthcare-associated UTI. Introduction of UPEC into the mammalian urinary tract evokes a well-described inflammatory response, comprising pro-inflammatory cytokines and chemokines as well as cellular elements (neutrophils and macrophages). In human UTI, this inflammatory response contributes to symptomatology and provides means for diagnosis by standard clinical testing. Early in acute cystitis, as demonstrated in murine models, UPEC gains access to an intracellular niche that protects a population of replicating bacteria from arriving phagocytes. To ensure the establishment of this protected niche, UPEC employ multiple strategies to attenuate and delay the initiation of host inflammatory components, including epithelial secretion of chemoattractants. Recent work has also revealed novel mechanisms by which UPEC blunts neutrophil migration across infected uroepithelium. Taken together, these attributes distinguish UPEC from commensal and nonpathogenic E. coli strains. This review highlights the unique immune evasion and suppression strategies of this bacterial pathogen and offers directions for further study; molecular understanding of these mechanisms will inform the development of adjunctive, anti-virulence therapeutics for UTI.

  12. Genomic Islands of Uropathogenic Escherichia coli Contribute to Virulence▿ †

    PubMed Central

    Lloyd, Amanda L.; Henderson, Tiffany A.; Vigil, Patrick D.; Mobley, Harry L. T.

    2009-01-01

    Uropathogenic Escherichia coli (UPEC) strain CFT073 contains 13 large genomic islands ranging in size from 32 kb to 123 kb. Eleven of these genomic islands were individually deleted from the genome, and nine isogenic mutants were tested for their ability to colonize the CBA/J mouse model of ascending urinary tract infection. Three genomic island mutants (ΔPAI-aspV, ΔPAI-metV, and ΔPAI-asnT) were significantly outcompeted by wild-type CFT073 in the bladders and/or kidneys following transurethral cochallenge (P ≤ 0.0139). The PAI-metV mutant also showed significant attenuation in the ability to independently colonize the kidneys (P = 0.0011). Specific genes within these islands contributed to the observed phenotype, including a previously uncharacterized iron acquisition cluster, fbpABCD (c0294 to c0297 [c0294-97]), autotransporter, picU (c0350), and RTX family exoprotein, tosA (c0363) in the PAI-aspV island. The double deletion mutant with deletions in both copies of the fbp iron acquisition operon (Δc0294-97 Δc2518-15) was significantly outcompeted by wild-type CFT073 in cochallenge. Strains with mutations in a type VI secretion system within the PAI-metV island did not show attenuation. The attenuation of the PAI-metV island was localized to genes c3405-10, encoding a putative phosphotransferase transport system, which is common to UPEC and avian pathogenic E. coli strains but absent from E. coli K-12. We have shown that, in addition to encoding virulence genes, genomic islands contribute to the overall fitness of UPEC strain CFT073 in vivo. PMID:19329634

  13. Hemolysin of uropathogenic Escherichia coli: A cloak or a dagger?

    PubMed

    Ristow, Laura C; Welch, Rodney A

    2016-03-01

    Hemolysin from uropathogenic Escherichia coli (UPEC) is a hemolytic and cytotoxic protein active against a broad range of species and cell types. Expression of hemolysin correlates with severity of infection, as up to 78% of UPEC isolates from pyelonephritis cases express hemolysin. Despite decades of research on hemolysin activity, the mechanism of intoxication and the function of hemolysin in UPEC infection remain elusive. Early in vitro research established the role of hemolysin as a lytic protein at high doses. It is hypothesized that hemolysin is secreted at sublytic doses in vivo and recent research has focused on understanding the more subtle effects of hemolysin both in vitro and in elegant infection models in vivo, including inoculation by micropuncture of individual kidney nephrons. As the field continues to evolve, comparisons of hemolysin function in isolates from a range of UTI infections will be important for delineating the role of this toxin. This article is part of a Special Issue entitled: Pore-Forming Toxins edited by Mauro Dalla Serra and Franco Gambale.

  14. Virulence and Fitness Determinants of Uropathogenic Escherichia coli

    PubMed Central

    Subashchandrabose, Sargurunathan; Mobley, Harry L T.

    2015-01-01

    Urinary tract infection (UTI) caused by uropathogenic Escherichia coli (UPEC) is a major global public health concern. Increasing antibiotic resistance found in clinical UPEC isolates underscores the immediate need for development of novel therapeutics against this pathogen. Better understanding of the fitness and virulence mechanisms that are integral to the pathogenesis of UTI will facilitate identification of novel strategies to prevent and treat infection with UPEC. Working towards that goal, the global UPEC research community has made great strides at unraveling various virulence and fitness genes. Here, we summarize major findings on virulence and fitness determinants that enable UPEC to successfully survive and colonize the urinary tract of mammalian hosts. Major sections of this chapter are devoted to the role of iron acquisition systems, metabolic pathways, fimbriae, flagella, toxins, biofilm formation, capsule, and strain-specific genes in the initiation and progression of UTIs. Transcriptomes of UPEC during experimental UTI in a murine model and naturally occurring UTI in women are compared to elucidate virulence mechanisms specifically involved in human UTI. Capitalizing on the advances in molecular pathogenesis research by translating these findings will help develop better clinical strategies for prevention and management of UTIs. PMID:26350328

  15. Ferritinophagy drives uropathogenic Escherichia coli persistence in bladder epithelial cells.

    PubMed

    Bauckman, Kyle A; Mysorekar, Indira U

    2016-05-01

    Autophagy is a cellular recycling pathway, which in many cases, protects host cells from infections by degrading pathogens. However, uropathogenic Escherichia coli (UPEC), the predominant cause of urinary tract infections (UTIs), persist within the urinary tract epithelium (urothelium) by forming reservoirs within autophagosomes. Iron is a critical nutrient for both host and pathogen, and regulation of iron availability is a key host defense against pathogens. Iron homeostasis depends on the shuttling of iron-bound ferritin to the lysosome for recycling, a process termed ferritinophagy (a form of selective autophagy). Here, we demonstrate for the first time that UPEC shuttles with ferritin-bound iron into the autophagosomal and lysosomal compartments within the urothelium. Iron overload in urothelial cells induces ferritinophagy in an NCOA4-dependent manner causing increased iron availability for UPEC, triggering bacterial overproliferation and host cell death. Addition of even moderate levels of iron is sufficient to increase and prolong bacterial burden. Furthermore, we show that lysosomal damage due to iron overload is the specific mechanism causing host cell death. Significantly, we demonstrate that host cell death and bacterial burden can be reversed by inhibition of autophagy or inhibition of iron-regulatory proteins, or chelation of iron. Together, our findings suggest that UPEC persist in host cells by taking advantage of ferritinophagy. Thus, modulation of iron levels in the bladder may provide a therapeutic avenue to controlling UPEC persistence, epithelial cell death, and recurrent UTIs.

  16. Virulence and Fitness Determinants of Uropathogenic Escherichia coli.

    PubMed

    Subashchandrabose, Sargurunathan; Mobley, Harry L T

    2015-08-01

    Urinary tract infection (UTI) caused by uropathogenic Escherichia coli (UPEC) is a major global public health concern. Increasing antibiotic resistance found in clinical UPEC isolates underscores the immediate need for development of novel therapeutics against this pathogen. Better understanding of the fitness and virulence mechanisms that are integral to the pathogenesis of UTI will facilitate identification of novel strategies to prevent and treat infection with UPEC. Working towards that goal, the global UPEC research community has made great strides at unraveling various virulence and fitness genes. Here, we summarize major findings on virulence and fitness determinants that enable UPEC to successfully survive and colonize the urinary tract of mammalian hosts. Major sections of this chapter are devoted to the role of iron acquisition systems, metabolic pathways, fimbriae, flagella, toxins, biofilm formation, capsule, and strain-specific genes in the initiation and progression of UTIs. Transcriptomes of UPEC during experimental UTI in a murine model and naturally occurring UTI in women are compared to elucidate virulence mechanisms specifically involved in human UTI. Capitalizing on the advances in molecular pathogenesis research by translating these findings will help develop better clinical strategies for prevention and management of UTIs.

  17. Identification of DNA sequences from a second pathogenicity island of uropathogenic Escherichia coli CFT073: probes specific for uropathogenic populations.

    PubMed

    Rasko, D A; Phillips, J A; Li, X; Mobley, H L

    2001-10-15

    Uropathogenic Escherichia coli is the leading cause of urinary tract infection and hospital visits in North America. Cystitis and acute pyelonephritis, infection of the bladder and kidney, respectively, are the two most common syndromes encountered in patients with urinary tract infection. We sequenced and annotated 71,684 bases of a previously unidentified pathogenicity-associated island (PAI) from E. coli strain CFT073. This PAI contained 89 open-reading frames encoding a pap operon, iron-regulated genes, mobile genetic elements, and a large proportion of unknown or unidentified open-reading frames. Dot blot analysis with 11 DNA sequences from this PAI demonstrated that 7 sequences were more prevalent among uropathogens: 2 probes were more prevalent among cystitis and pyelonephritis isolates, 2 among pyelonephritis isolates only, and 3 among cystitis isolates only than among fecal isolates. These data suggest that groups of uropathogens have genetic differences that may be responsible for the different clinical outcomes.

  18. Distribution of uropathogenic virulence factors among Escherichia coli strains isolated from dogs and cats.

    PubMed

    Yuri, K; Nakata, K; Katae, H; Yamamoto, S; Hasegawa, A

    1998-03-01

    A variety of virulence factors (VFs) such as type 1 fimbriae, pilus associated with pyelonephritis, S fimbriae, afimbrial adhesin, alpha-hemolysin, aerobactin and cytotoxic necrotizing factor 1 are associated with uropathogenic Escherichia coli. In this study, 80 uropathogenic E. coli strains in 50 dogs and 30 cats suffering from UTI. In addition, 60 E. coli strains were isolated from fecal samples from 30 each of healthy dogs and cats. The distribution of VFs of uropathogenic E. coli strains isolated from dogs and cats suffering from urinary tract infections (UTI) were examined by the colony hybridization test with seven DNA probes specific for VFs, and the results were compared with those obtained in the studies on strains from humans with UTI. In uropathogenic E. coli strains isolated from dogs and cats suffering from UTI, VFs were detected as frequently as in the strains isolated from humans with UTI. Although less frequently, genes encoding these VFs especially pap, sfa, hly, and cnf 1 genes were also associated with E. coli strains isolated from feces of healthy cats, in contrast to the distribution pattern of uropathogenic E. coli observed in humans. Furthermore, all VFs except pil were significantly more frequently detected in strains isolated from urine of animals with cystitis than in those isolated from feces of healthy humans. These results indicate that VFs of E. coli contribute to the pathogenesis of UTI in dogs and cats.

  19. Whole-genome sequencing of uropathogenic Escherichia coli reveals long evolutionary history of diversity and virulence.

    PubMed

    Lo, Yancy; Zhang, Lixin; Foxman, Betsy; Zöllner, Sebastian

    2015-08-01

    Uropathogenic Escherichia coli (UPEC) are phenotypically and genotypically very diverse. This diversity makes it challenging to understand the evolution of UPEC adaptations responsible for causing urinary tract infections (UTI). To gain insight into the relationship between evolutionary divergence and adaptive paths to uropathogenicity, we sequenced at deep coverage (190×) the genomes of 19 E. coli strains from urinary tract infection patients from the same geographic area. Our sample consisted of 14 UPEC isolates and 5 non-UTI-causing (commensal) rectal E. coli isolates. After identifying strain variants using de novo assembly-based methods, we clustered the strains based on pairwise sequence differences using a neighbor-joining algorithm. We examined evolutionary signals on the whole-genome phylogeny and contrasted these signals with those found on gene trees constructed based on specific uropathogenic virulence factors. The whole-genome phylogeny showed that the divergence between UPEC and commensal E. coli strains without known UPEC virulence factors happened over 32 million generations ago. Pairwise diversity between any two strains was also high, suggesting multiple genetic origins of uropathogenic strains in a small geographic region. Contrasting the whole-genome phylogeny with three gene trees constructed from common uropathogenic virulence factors, we detected no selective advantage of these virulence genes over other genomic regions. These results suggest that UPEC acquired uropathogenicity long time ago and used it opportunistically to cause extraintestinal infections.

  20. Escherichia coli mediated urinary tract infections: are there distinct uropathogenic E. coli (UPEC) pathotypes?

    PubMed

    Marrs, Carl F; Zhang, Lixin; Foxman, Betsy

    2005-11-15

    A variety of virulence genes are associated with Escherichia coli mediated urinary tract infections. Particular sets of virulence factors shared by bacterial strains directing them through a particular pathogenesis process are called a "pathotype." Comparison of co-occurrence of potential urinary tract infection (UTI) virulence genes among different E. coli isolates from fecal and UTI collections provides evidence for multiple pathotypes of uropathogenic E. coli, but current understanding of critical genetic differences defining the pathotypes is limited. Discovery of additional E. coli genes involved in uropathogenesis and determination of their distribution and co-occurrences will further define UPEC pathotypes and allow for a more detailed analysis of how these pathotypes might differ in how they cause disease.

  1. Draft Genome Sequence of Brazilian Escherichia coli Uropathogenic Strain E2

    PubMed Central

    Pieta, Luiza; Prichula, Janira; Sambrano, Gustavo E.; Soares, Renata; Caierão, Juliana; Frazzon, Jeverson; d’Azevedo, Pedro A.

    2016-01-01

    Escherichia coli is a common pathogen recovered from cystitis infections. In this report, we announce the draft genome sequence of strain E2 isolated from the urine specimen from a female patient in South Brazil. The genome assembly has 5,081,209 bp, a G+C content of 50.57%, and virulence factors associated with both enteroaggregative and uropathogenic E. coli strains. PMID:27795253

  2. Origins and Virulence Mechanisms of Uropathogenic Escherichia coli

    PubMed Central

    Wiles, Travis J.; Kulesus, Richard R.; Mulvey, Matthew A.

    2008-01-01

    Strains of uropathogenic E. coli (UPEC) are the primary cause of urinary tract infections, including both cystitis and pyelonephritis. These bacteria have evolved a multitude of virulence factors and strategies that facilitate bacterial growth and persistence within the adverse settings of the host urinary tract. Expression of adhesive organelles like type 1 and P pili allow UPEC to bind and invade host cells and tissues within the urinary tract while expression of iron chelating factors (siderophores) enable UPEC to pilfer host iron stores. Deployment of an array of toxins, including hemolysin and cytotoxic necrotizing factor 1, provide UPEC with the means to inflict extensive tissue damage, facilitating bacterial dissemination as well as releasing host nutrients and disabling immune effector cells. These toxins also have the capacity to modulate, in more subtle ways, host signaling pathways affecting myriad processes, including inflammatory responses, host cell survival, and cytoskeletal dynamics. Here, we discuss the mechanisms by which these and other virulence factors promote UPEC survival and growth within the urinary tract. Comparisons are also made between UPEC and other strains of extraintestinal pathogenic E. coli that, although closely related to UPEC, are distinct in their abilities to colonize the host and cause disease. PMID:18482721

  3. Uropathogenic Escherichia coli (UPEC) strains may carry virulence properties of diarrhoeagenic E. coli.

    PubMed

    Abe, Cecilia M; Salvador, Fábia A; Falsetti, Ivan N; Vieira, Mônica A M; Blanco, Jorge; Blanco, Jesús E; Blanco, Miguel; Machado, Antônia M O; Elias, Waldir P; Hernandes, Rodrigo T; Gomes, Tânia A T

    2008-04-01

    To analyze whether Escherichia coli strains that cause urinary tract infections (UPEC) share virulence characteristics with the diarrheagenic E. coli (DEC) pathotypes and to recognize their genetic diversity, 225 UPEC strains were examined for the presence of various properties of DEC and UPEC (type of interaction with HeLa cells, serogroups and presence of 30 virulence genes). No correlation between adherence patterns and serogroups was observed. Forty-five serogroups were found, but 64% of the strains belonged to one of the 12 serogroups (O1, O2, O4, O6, O7, O14, O15, O18, O21, O25, O75, and O175) and carried UPEC virulence genes (pap, hly, aer, sfa, cnf). The DEC genes found were: aap, aatA, aggC, agg3C, aggR, astA, eae, ehly, iha, irp2, lpfA(O113), pet, pic, pilS, and shf. Sixteen strains presented aggregative adherence and/or the aatA sequence, which are characteristics of enteroaggregative E. coli (EAEC), one of the DEC pathotypes. In summary, certain UPEC strains may carry DEC virulence properties, mostly associated to the EAEC pathotype. This finding raises the possibility that at least some faecal EAEC strains might represent potential uropathogens. Alternatively, certain UPEC strains may have acquired EAEC properties, becoming a potential cause of diarrhoea.

  4. Isolation of generalized transducing bacteriophages for uropathogenic strains of Escherichia coli.

    PubMed

    Battaglioli, E J; Baisa, G A; Weeks, A E; Schroll, R A; Hryckowian, A J; Welch, R A

    2011-09-01

    The traditional genetic procedure for random or site-specific mutagenesis in Escherichia coli K-12 involves mutagenesis, isolation of mutants, and transduction of the mutation into a clean genetic background. The transduction step reduces the likelihood of complications due to secondary mutations. Though well established, this protocol is not tenable for many pathogenic E. coli strains, such as uropathogenic strain CFT073, because it is resistant to known K-12 transducing bacteriophages, such as P1. CFT073 mutants generated via a technique such as lambda Red mutagenesis may contain unknown secondary mutations. Here we describe the isolation and characterization of transducing bacteriophages for CFT073. Seventy-seven phage isolates were acquired from effluent water samples collected from a wastewater treatment plant in Madison, WI. The phages were differentiated by a host sensitivity-typing scheme with a panel of E. coli strains from the ECOR collection and clinical uropathogenic isolates. We found 49 unique phage isolates. These were then examined for their ability to transduce antibiotic resistance gene insertions at multiple loci between different mutant strains of CFT073. We identified 4 different phages capable of CFT073 generalized transduction. These phages also plaque on the model uropathogenic E. coli strains 536, UTI89, and NU14. The highest-efficiency transducing phage, ΦEB49, was further characterized by DNA sequence analysis, revealing a double-stranded genome 47,180 bp in length and showing similarity to other sequenced phages. When combined with a technique like lambda Red mutagenesis, the newly characterized transducing phages provide a significant development in the genetic tools available for the study of uropathogenic E. coli.

  5. Characterization of adhesion associated surface properties of uropathogenic Escherichia coli.

    PubMed

    Bartková, G; Ciznár, I; Lehotská, V; Kernová, T

    1994-01-01

    Escherichia coli was isolated from the urine of patients with pyelonephritis, with urinary tract infections other than pyelonephritis and with asymptomatic bacteriuria. Surface properties of the strains were analyzed by the salting-out aggregation test (SAT), hydrophobic interaction chromatography (HIC), Congo red binding (Crb), agglutination of erythrocytes (MRHA) and latex particles covered by digalactoside (PF) and by adherence to tissue culture cells. In addition, a DNA probe for the pap gene was used. The DNA probe detected the highest proportion of strains with pap gene in the group of patients with pyelonephritis, lower in the urinary tract infections other than pyelonephritis and the lowest in the group with asymptomatic bacteriuria. Tests for P-fimbriae (PF, MRHA) showed a similar distribution. Hydrophobicity measured by SAT and by HIC did not show differences among the tested groups of strains. The results suggest that factors other than the P-fimbriae and hydrophobicity may contribute to the persistence of E. coli in the urinary tract.

  6. ESBL-producing uropathogenic Escherichia coli isolated from dogs and cats in Switzerland.

    PubMed

    Huber, Helen; Zweifel, Claudio; Wittenbrink, Max M; Stephan, Roger

    2013-03-23

    Extended-spectrum β-lactamase (ESBL)-producing Escherichia (E.) coli have emerged in human and veterinary medicine. The aim of this study was to investigate the presence of ESBL-producers among uropathogenic E. coli isolated from dogs and cats and to characterize detected ESBL-producing isolates by antibiotic susceptibility testing, identification of ESBL genes, multi-locus sequence typing (MLST), detection of putative virulence genes, and analysis of E. coli phylogroups. Among the 107 E. coli isolates derived from urinary samples (59 from dogs, 40 from cats), eight isolates from four different animals (two dogs, two cats) were found to be ESBL-producers. These isolates were of ST533/CTX-M-15/TEM/phylogroup B1 (four strains from one dog), ST410/CTX-M-15/TEM/phylogroup A (three strains, one from a dog and two from a cat), and ST648/CTX-M-15/phylogroup D (one strain from a cat). In terms of putative virulence factors, all isolates harbored lpfA, sat, and tsh, whereas iss was only detected in strains of ST533. Thus, ESBL-producers were detected among uropathogenic E. coli from Swiss companion animals and the eight CTX-M-15-producing isolates belonged to three sequence types (ST410, ST533, ST648) and three E. coli phylogroups (A, B1, D). For the first time, E. coli of ST533 carrying bla(CTX-M-15) were thereby detected in a dog.

  7. Photoluminescent gold nanoclusters as sensing probes for uropathogenic Escherichia coli.

    PubMed

    Chan, Po-Han; Ghosh, Bhaswati; Lai, Hong-Zheng; Peng, Hwei-Ling; Mong, Kwok Kong Tony; Chen, Yu-Chie

    2013-01-01

    Glycan-bound nanoprobes have been demonstrated as suitable sensing probes for bacteria containing glycan binding sites. In this study, we demonstrated a facile approach for generating glycan-bound gold nanoclusters (AuNCs). The generated AuNCs were used as sensing probes for corresponding target bacteria. Mannose-capped AuNCs (AuNCs@Mann) were generated and used as the model sensors for target bacteria. A one-step synthesis approach was employed to generate AuNCs@Mann. In this approach, an aqueous solution of tetrachloroauric acid and mannoside that functionized with a thiol group (Mann-SH) was stirred at room temperature for 48 h. The mannoside functions as reducing and capping agent. The size of the generated AuNCs@Mann is 1.95±0.27 nm, whereas the AuNCs with red photoluminescence have a maximum emission wavelength of ~630 nm (λexcitation = 375 nm). The synthesis of the AuNCs@Mann was accelerated by microwave heating, which enabled the synthesis of the AuNCs@Mann to complete within 1 h. The generated AuNCs@Mann are capable of selectively binding to the urinary tract infection isolate Escherichia coli J96 containing the mannose binding protein FimH expressed on the type 1 pili. On the basis of the naked eye observation, the limit of detection of the sensing approach is as low as ~2×10(6) cells/mL.

  8. Prevalence and Persistence of Escherichia coli Strains with Uropathogenic Virulence Characteristics in Sewage Treatment Plants▿

    PubMed Central

    Anastasi, E. M.; Matthews, B.; Gundogdu, A.; Vollmerhausen, T. L.; Ramos, N. L.; Stratton, H.; Ahmed, W.; Katouli, M.

    2010-01-01

    We investigated the prevalence and persistence of Escherichia coli strains in four sewage treatment plants (STPs) in a subtropical region of Queensland, Australia. In all, 264 E. coli strains were typed using a high-resolution biochemical fingerprinting method and grouped into either a single or a common biochemical phenotype (S-BPT and C-BPT, respectively). These strains were also tested for their phylogenetic groups and 12 virulence genes associated with intestinal and extraintestinal E. coli strains. Comparison of BPTs at various treatment stages indicated that certain BPTs were found in two or all treatment stages. These BPTs constituted the highest proportion of E. coli strains in each STP and belonged mainly to phylogenetic group B2 and, to a lesser extent, group D. No virulence genes associated with intestinal E. coli were found among the strains, but 157 (59.5%) strains belonging to 14 C-BPTs carried one or more virulence genes associated with uropathogenic strains. Of these, 120 (76.4%) strains belonged to seven persistent C-BPTs and were found in all four STPs. Our results indicate that certain clonal groups of E. coli with virulence characteristics of uropathogenic strains can survive the treatment processes of STPs. These strains were common to all STPs and constituted the highest proportion of the strains in different treatment tanks of each STP. PMID:20622128

  9. Sub-MIC ciprofloxacin effect on fimbrial production by uropathogenic Escherichia coli strains.

    PubMed

    Lo Bue, A M; Geremia, E; Castagna, C; Chisari, G; Nicoletti, G

    1999-10-01

    The urine from 210 patients with acute urinary tract infection (UTI) was examined to study the in vitro effect of ciprofloxacin on fimbriae production by uropathogenic Escherichia coli isolates. Forty-nine bacterial samples of density 10(5) CFU/ml were not considered. From the resulting 161 samples, E. coli was the major strain found, present in 54 samples. Other microoganisms found were: Enterococcus sp. (34 samples), Staphylococcus epidermis (22), yeasts (11), Proteus sp. (11), Pseudomonas sp. (11), Klebsiella sp. (8), Enterobacter sp. (6), Citrobacter sp. (3), and Acinetobacter sp. (1). The uropathogenic E. coli strains found were P-fimbriated, as demonstrated by hemoagglutination activity against human erythrocytes with and without mannose, SDS-PAGE of fimbrial proteins and transmission electron microscopy (TEM). All E. coli strains found were exposed in vitro to sub-inhibitory concentrations of ciprofloxacin (1/8 MIC). Our results showed that: 1) P-fimbriated E. coli is the most prevalent microorganism in acute UTI (34%); 2) exposure to sub-MICs of ciprofloxacin inhibits fimbrial production in 79% of E. coli strains; 3) the pattern of SDS-PAGE fimbrial proteins is modified after exposure; in particular, the most affected synthesis involves the protein at 18 kD known as P-fimbriae. PMID:10632381

  10. In vitro activity of commercial probiotic Lactobacillus strains against uropathogenic Escherichia coli.

    PubMed

    Delley, Michèle; Bruttin, Anne; Richard, Michel; Affolter, Michael; Rezzonico, Enea; Brück, Wolfram M

    2015-07-01

    Urinary tract infection (UTI) is one of the most prevalent infections in humans. In ≥80% of cases, the etiologic agents are strains of uropathogenic Escherichia coli (UPEC), which commonly reside in the gastrointestinal tract. Lactobacilli have been shown to prevent UTI reoccurrence by restoring the urogenital microbiota when administered vaginally or orally. The goal of this study was to determine if commercial probiotic Lactobacillus spp. reduce or clear UPEC in vitro. Results show that it is likely that lactobacilli may, in addition to restoring a healthy urogenital microbiota through acidification of their environment, also displace adhering UPEC and cause a reduction of infection.

  11. Modeling the inactivatin of Escherichia coli 0157:H7 and uropathogenic E. coli in ground beef by high pressure processing and citral

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Disease causing Escherichia coli commonly found in meat and poultry include intestinal pathogenic E. coli (iPEC) as well as extraintestinal types such as the Uropathogenic E. coli (UPEC). In this study we compared the resistance of iPEC (O157:H7) to UPEC in ground beef using High Pressure Processing...

  12. Modeling the inactivation of Escherichia coli 0157:H7 and uropathogenic E.coli in ground chicken by high pressure processing and thymol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Disease causing Escherichia coli commonly found in meat and poultry include intestinal pathogenic E. coli (iPEC) as well as extraintestinal types such as the Uropathogenic E. coli (UPEC). In this study we compare the resistance of iPEC (O157:H7) to UPEC in chicken meat using High Pressure Processing...

  13. Genome of multidrug-resistant uropathogenic Escherichia coli strain NA114 from India.

    PubMed

    Avasthi, Tiruvayipati Suma; Kumar, Narender; Baddam, Ramani; Hussain, Arif; Nandanwar, Nishant; Jadhav, Savita; Ahmed, Niyaz

    2011-08-01

    Uropathogenic Escherichia coli (UPEC) causes serious infections in people at risk and has a significant environmental prevalence due to contamination by human and animal excreta. In developing countries, UPEC assumes importance in certain dwellings because of poor community/personal hygiene and exposure to contaminated water or soil. We report the complete genome sequence of E. coli strain NA114 from India, a UPEC strain with a multidrug resistance phenotype and the capacity to produce extended-spectrum beta-lactamase. The genome sequence and comparative genomics emanating from it will be significant in under-standing the genetic makeup of diverse UPEC strains and in boosting the development of new diagnostics/vaccines. PMID:21685291

  14. Role of Uropathogenic Escherichia coli Virulence Factors in Development of Urinary Tract Infection and Kidney Damage

    PubMed Central

    Bien, Justyna; Sokolova, Olga; Bozko, Przemyslaw

    2012-01-01

    Uropathogenic Escherichia coli (UPEC) is a causative agent in the vast majority of urinary tract infections (UTIs), including cystitis and pyelonephritis, and infectious complications, which may result in acute renal failure in healthy individuals as well as in renal transplant patients. UPEC expresses a multitude of virulence factors to break the inertia of the mucosal barrier. In response to the breach by UPEC into the normally sterile urinary tract, host inflammatory responses are triggered leading to cytokine production, neutrophil influx, and the exfoliation of infected bladder epithelial cells. Several signaling pathways activated during UPEC infection, including the pathways known to activate the innate immune response, interact with calcium-dependent signaling pathways. Some UPEC isolates, however, might possess strategies to delay or suppress the activation of components of the innate host response in the urinary tract. Studies published in the recent past provide new information regarding how virulence factors of uropathogenic E. coli are involved in activation of the innate host response. Despite numerous host defense mechanisms, UPEC can persist within the urinary tract and may serve as a reservoir for recurrent infections and serious complications. Presentation of the molecular details of these events is essential for development of successful strategies for prevention of human UTIs and urological complications associated with UTIs. PMID:22506110

  15. Uropathogenic virulence factor FimH facilitates binding of uteropathogenic Escherichia coli to canine endometrium.

    PubMed

    Krekeler, N; Marenda, M S; Browning, G F; Holden, K M; Charles, J A; Wright, P J

    2012-09-01

    Pyometra is a potentially life-threatening condition in bitches and is often caused by Escherichia coli infection. Both pathogenic and non-pathogenic E. coli strains commonly carry the genes for type 1 fimbriae that mediate bacterial adhesion onto host epithelium. To investigate whether the type 1 fimbrial adhesin, FimH, facilitates the binding of uropathogenic E. coli to canine endometrium, the fimH gene was insertionally inactivated in a pathogenic E. coli strain. The ability of E. coli to bind to canine endometrial epithelial cells was determined in vitro using canine uterine biopsies. Binding of the fimH mutant was only 0.3% of that of the wild type. Complementation of the mutation restored the phenotype to that of the parent. This study has developed an in vitro model that allows quantitative and qualitative assessment of bacterial binding to canine endometrium and has demonstrated that the fimH gene plays a role in adherence of pathogenic E. coli to canine endometrium. PMID:22554919

  16. The serum resistome of a globally disseminated multidrug resistant uropathogenic Escherichia coli clone.

    PubMed

    Phan, Minh-Duy; Peters, Kate M; Sarkar, Sohinee; Lukowski, Samuel W; Allsopp, Luke P; Gomes Moriel, Danilo; Achard, Maud E S; Totsika, Makrina; Marshall, Vikki M; Upton, Mathew; Beatson, Scott A; Schembri, Mark A

    2013-01-01

    Escherichia coli ST131 is a globally disseminated, multidrug resistant clone responsible for a high proportion of urinary tract and bloodstream infections. The rapid emergence and successful spread of E. coli ST131 is strongly associated with antibiotic resistance; however, this phenotype alone is unlikely to explain its dominance amongst multidrug resistant uropathogens circulating worldwide in hospitals and the community. Thus, a greater understanding of the molecular mechanisms that underpin the fitness of E. coli ST131 is required. In this study, we employed hyper-saturated transposon mutagenesis in combination with multiplexed transposon directed insertion-site sequencing to define the essential genes required for in vitro growth and the serum resistome (i.e. genes required for resistance to human serum) of E. coli EC958, a representative of the predominant E. coli ST131 clonal lineage. We identified 315 essential genes in E. coli EC958, 231 (73%) of which were also essential in E. coli K-12. The serum resistome comprised 56 genes, the majority of which encode membrane proteins or factors involved in lipopolysaccharide (LPS) biosynthesis. Targeted mutagenesis confirmed a role in serum resistance for 46 (82%) of these genes. The murein lipoprotein Lpp, along with two lipid A-core biosynthesis enzymes WaaP and WaaG, were most strongly associated with serum resistance. While LPS was the main resistance mechanism defined for E. coli EC958 in serum, the enterobacterial common antigen and colanic acid also impacted on this phenotype. Our analysis also identified a novel function for two genes, hyxA and hyxR, as minor regulators of O-antigen chain length. This study offers novel insight into the genetic make-up of E. coli ST131, and provides a framework for future research on E. coli and other Gram-negative pathogens to define their essential gene repertoire and to dissect the molecular mechanisms that enable them to survive in the bloodstream and cause disease.

  17. The Serum Resistome of a Globally Disseminated Multidrug Resistant Uropathogenic Escherichia coli Clone

    PubMed Central

    Phan, Minh-Duy; Peters, Kate M.; Sarkar, Sohinee; Lukowski, Samuel W.; Allsopp, Luke P.; Moriel, Danilo Gomes; Achard, Maud E. S.; Totsika, Makrina; Marshall, Vikki M.; Upton, Mathew; Beatson, Scott A.; Schembri, Mark A.

    2013-01-01

    Escherichia coli ST131 is a globally disseminated, multidrug resistant clone responsible for a high proportion of urinary tract and bloodstream infections. The rapid emergence and successful spread of E. coli ST131 is strongly associated with antibiotic resistance; however, this phenotype alone is unlikely to explain its dominance amongst multidrug resistant uropathogens circulating worldwide in hospitals and the community. Thus, a greater understanding of the molecular mechanisms that underpin the fitness of E. coli ST131 is required. In this study, we employed hyper-saturated transposon mutagenesis in combination with multiplexed transposon directed insertion-site sequencing to define the essential genes required for in vitro growth and the serum resistome (i.e. genes required for resistance to human serum) of E. coli EC958, a representative of the predominant E. coli ST131 clonal lineage. We identified 315 essential genes in E. coli EC958, 231 (73%) of which were also essential in E. coli K-12. The serum resistome comprised 56 genes, the majority of which encode membrane proteins or factors involved in lipopolysaccharide (LPS) biosynthesis. Targeted mutagenesis confirmed a role in serum resistance for 46 (82%) of these genes. The murein lipoprotein Lpp, along with two lipid A-core biosynthesis enzymes WaaP and WaaG, were most strongly associated with serum resistance. While LPS was the main resistance mechanism defined for E. coli EC958 in serum, the enterobacterial common antigen and colanic acid also impacted on this phenotype. Our analysis also identified a novel function for two genes, hyxA and hyxR, as minor regulators of O-antigen chain length. This study offers novel insight into the genetic make-up of E. coli ST131, and provides a framework for future research on E. coli and other Gram-negative pathogens to define their essential gene repertoire and to dissect the molecular mechanisms that enable them to survive in the bloodstream and cause disease. PMID

  18. Pathogenicity island sequences of pyelonephritogenic Escherichia coli CFT073 are associated with virulent uropathogenic strains.

    PubMed

    Kao, J S; Stucker, D M; Warren, J W; Mobley, H L

    1997-07-01

    Urinary tract infection is the most frequently diagnosed kidney and urologic disease, and Escherichia coli is by far the most common etiologic agent. Defined blocks of DNA termed pathogenicity islands have been found in uropathogenic strains to carry genes not generally found in fecal strains. We have identified one of these regions of DNA within the chromosome of the highly virulent E. coli CFT073, isolated from the blood and urine of a woman with acute pyelonephritis. This strain, which is cytotoxic for cultured renal cells and causes acute pyelonephritis in transurethrally infected CBA mice, contains two distinct copies of the pap operon and is hemolytic. One pap operon was localized on a cosmid clone which was used to identify three overlapping cosmid clones. By using restriction mapping, DNA hybridization, sequencing, and PCR amplification, a region of approximately 50 kb was found to be present in this uropathogenic strain and to have no corresponding sequences in E. coli K-12. This gene block also carries hemolysin genes hlyCABD. The pathogenicity island begins 7 bp downstream of dadX (catabolic alanine racemase; 26.55 min) and ends at a position in the K-12 genome 75 bp downstream of the metV tRNA gene (62.74 min); this suggests that a chromosomal rearrangement has occurred relative to the K-12 linkage map. The junctions of the pathogenicity island were verified by PCR amplification directly from the genomic DNA of strain CFT073. DNA sequencing within the boundaries of the junctions revealed genes not previously identified in E. coli or in some cases bearing no known homologs. When used as probes for DNA hybridization, these sequences were found significantly more often in strains associated with the clinical syndromes of cystitis (82%) and acute pyelonephritis (79%) than in fecal strains (19%; P < 0.001).

  19. Serological response to the P fimbriae of uropathogenic Escherichia coli in pyelonephritis.

    PubMed Central

    de Ree, J M; van den Bosch, J F

    1987-01-01

    Uropathogenic Escherichia coli strains isolated from four patients with pyelonephritis were characterized by their O:K serotype, hemolysin production, mannose-resistant hemagglutination, and the serotype of the P fimbriae. These P fimbriae were serotyped with specific monoclonal antibodies. Serum samples from the patients were analyzed for the presence of specific antibodies to the P fimbriae. In all cases antifimbrial antibodies were found, strongly suggesting that these P fimbriae are expressed in vivo. However, the antibodies in the patient sera were not able to inhibit the mannose-resistant hemagglutination. This finding suggests that these antibodies react with the fimbrial components and not with the minor components which are responsible for adhesion. PMID:2887515

  20. Transcriptional Responses of Uropathogenic Escherichia coli to Increased Environmental Osmolality Caused by Salt or Urea

    PubMed Central

    Withman, Benjamin; Gunasekera, Thusitha S.; Beesetty, Pavani; Agans, Richard

    2013-01-01

    Uropathogenic Escherichia coli (UPEC) is the most common causative agent of urinary tract infections in humans. The majority of urinary infections develop via ascending route through the urethra, where bacterial cells come in contact with human urine prior to reaching the bladder or kidneys. Since urine contains significant amounts of inorganic ions and urea, it imposes osmotic and denaturing stresses on bacterial cells. In this study, we determined the transcriptional adaptive responses of UPEC strain CFT073 to the presence of 0.3 M NaCl or 0.6 M urea in the growth medium. The cell responses to these two osmolytes were drastically different. Although most of the genes of the osmotically inducible regulon were overexpressed in medium with salt, urea failed to stimulate osmotic stress response. At the same time, UPEC colonization genes encoding type 1 and F1C fimbriae and capsule biosynthesis were transcriptionally induced in the presence of urea but did not respond to increased salt concentration. We speculate that urea can potentially be sensed by uropathogenic bacteria to initiate infection program. In addition, several molecular chaperone genes were overexpressed in the presence of urea, whereas adding NaCl to the medium led to an upregulation of a number of anaerobic metabolism pathways. PMID:23090957

  1. Innate immunity of surfactant proteins A and D in urinary tract infection with uropathogenic Escherichia coli

    PubMed Central

    Hu, Fengqi; Ding, Guohua; Zhang, Zhiyong; Gatto, Louis A.; Hawgood, Samuel; Poulain, Francis R.; Cooney, Robert N.; Wang, Guirong

    2015-01-01

    To investigate the effects of surfactant proteins A and D (SP-A, SP-D) in urinary tract infection (UTI), SP-A and SP-D double knockout (SP-A/D KO) and wild type (WT) C57BL/6 female mice were infected with uropathogenic Escherichia coli by intravesical inoculation. Compared with WT mice SP-A/D KO mice showed increased susceptibility to UTI as evidenced by higher bacterial CFU, more infiltrating neutrophils and severe pathological changes. Keratinocyte-derived chemokine increased in the kidney of WT mice but not in SP-A/D KO mice 24 h post-infection. Compared to control, level of IL-17 was elevated in the kidney of infected WT and SP-A/D KO mice and the level of IL-17 was higher in the infected SP-A/D KO mice than infected WT mice 24 and 48 h post-infection. Basal level of p38 MAPK phosphorylation in SP-A/D KO mice was higher compared to WT mice. Phosphorylated-p38 level was elevated in the kidney of WT mice post-infection but not in SP-A/D KO mice. Furthermore, in vitro growth of uropathogenic E. coli was inhibited by SP-A and SP-D. We conclude that SP-A and SP-D function as mediators of innate immunity by inhibiting bacterial growth and modulating renal inflammation in part by regulating p38 MAPK-related pathway in murine UTI. PMID:26511057

  2. Distribution of pathogenicity island markers in commensal and uropathogenic Escherichia coli isolates.

    PubMed

    Samei, Ali; Haghi, Fakhri; Zeighami, Habib

    2016-05-01

    Uropathogenic Escherichia coli (UPEC) isolates contain large genomic segments, termed pathogenicity islands (PAIs), that contribute to their virulence. A total of 150 UPEC and 50 commensal E. coli isolates from outpatients were investigated for antimicrobial susceptibility and the presence of eight PAI markers. One hundred ninety (95 %) isolates were resistant to one or more antimicrobial agents. The most frequent resistance found against amoxicillin (68 %), amoxicillin/clavulanic acid (55 %), aztreonam (50 %), trimethoprim/sulfamethoxazole (46 %) and tetracycline (43.5 %). Antimicrobial resistance among UPEC isolates was higher than that of commensals. PAI markers were detected in substantial percentage of commensal (88 %) and UPEC isolates (98.6 %) (P > 0.05). The most prevalent PAI marker among UPEC and commensal isolates was PAI IV536 (98.7 % UPEC vs. 84 % commensal). We found a high number of PAI markers such as PAI ICFT073, PAI IICFT073, PAI I536, PAI II536, PAI III536 and PAI IIJ96 significantly associated with UPEC. PAI III536 (21.3 %) and PAI IIJ96 (8 %) were detected only in the uropathogenic isolates. Several different combinations of PAIs were found among UPEC isolates. Comparison of PAIs among UPEC and commensal isolates showed that many UPEC isolates (79.3 %) carried two or more PAI markers, while 6 % of commensals had two PAI markers (P < 0.05). The most frequent combinations of PAI markers in UPEC isolates were PAI IV536 + PAI IICFT073 (18 %) and PAI IV536 + PAI ICFT073 + PAI IICFT073 (18 %). These results indicate that PAI markers are widespread among commensal and UPEC isolates and these commensal isolates may be reservoirs for transmission of these markers.

  3. Uropathogenic Escherichia coli strain CFT073 disrupts NLRP3 inflammasome activation

    PubMed Central

    Waldhuber, Anna; Puthia, Manoj; Wieser, Andreas; Cirl, Christine; Dürr, Susanne; Neumann-Pfeifer, Silke; Albrecht, Simone; Römmler, Franziska; Müller, Tina; Zheng, Yunji; Schubert, Sören; Groß, Olaf; Svanborg, Catharina

    2016-01-01

    Successful bacterial pathogens produce an array of virulence factors that allow subversion of the immune system and persistence within the host. For example, uropathogenic Escherichia coli strains, such as CFT073, express Toll/IL-1 receptor–containing (TIR-containing) protein C (TcpC), which impairs TLR signaling, thereby suppressing innate immunity in the urinary tract and enhancing persistence in the kidneys. Here, we have reported that TcpC also reduces secretion of IL-1β by directly interacting with the NACHT leucin-rich repeat PYD protein 3 (NLRP3) inflammasome, which is crucial for recognition of pathogens within the cytosol. At a low MOI, IL-1β secretion was minimal in CFT073-infected macrophages; however, IL-1β release was markedly increased in macrophages infected with CFT073 lacking tcpC. Induction of IL-1β secretion by CFT073 and tcpC–deficient CFT073 required the NLRP3 inflammasome. TcpC attenuated activation of the NLRP3 inflammasome by binding both NLRP3 and caspase-1 and thereby preventing processing and activation of caspase-1. Moreover, in a murine urinary tract infection model, CFT073 infection rapidly induced expression of the NLRP3 inflammasome in the bladder mucosa; however, the presence of TcpC in WT CFT073 reduced IL-1β levels in the urine of infected mice. Together, these findings illustrate how uropathogenic E. coli use the multifunctional virulence factor TcpC to attenuate innate immune responses in the urinary tract. PMID:27214553

  4. Tetracycline rapidly reaches all the constituent cells of uropathogenic Escherichia coli biofilms

    NASA Technical Reports Server (NTRS)

    Stone, G.; Wood, P.; Dixon, L.; Keyhan, M.; Matin, A.; Demain, A. L. (Principal Investigator)

    2002-01-01

    We have developed a method for visualizing Escherichia coli cells that are exposed to tetracycline in a biofilm, based on a previous report that liposomes containing the E. coli TetR(B) protein fluoresce when exposed to this antibiotic. By our method, cells devoid of TetR(B) also exhibited tetracycline-dependent fluorescence. At 50 microg of tetracycline ml(-1), planktonic cells of a uropathogenic E. coli (UPEC) strain developed maximal fluorescence after 7.5 to 10 min of exposure. A similar behavior was exhibited by cells in a 24- or 48-h UPEC biofilm, as examined by confocal laser microscopy, regardless of whether they lined empty spaces or occupied densely packed regions. Further, a comparison of phase-contrast and fluorescent images of corresponding biofilm zones showed that all the cells fluoresced. Thus, all the biofilm cells were exposed to tetracycline and there were no pockets within the biofilm where the antibiotic failed to reach. It also appeared unlikely that niches of reduced exposure to the antibiotic existed within the biofilms.

  5. High prevalence of multidrug-resistance uropathogenic Escherichia coli strains, Isfahan, Iran

    PubMed Central

    Dehbanipour, Razieh; Rastaghi, Sedighe; Sedighi, Mansour; Maleki, Nafiseh; Faghri, Jamshid

    2016-01-01

    Background and Objectives: Urinary tract infection (UTI) is one of the most frequent infectious diseases and can occur in all age groups. Escherichia coli is the main cause of this infection. Multiple resistances to antimicrobial agents are increasing quickly in E. coli isolates and may complicate therapeutic strategies for UTI. The aim of this study was to determine the antibiotic resistance pattern and the multidrug-resistance (MDR) phenotypes in uropathogenic E. coli (UPEC). Materials and Methods: A total of 135 UPEC isolates were collected from both outpatients (91 isolates) and inpatients (44 isolates) between September, 2012 and February, 2013. In order to determine the MDR among UPEC isolates, we have tested 15 antimicrobial agents and antibiotic susceptibility was done by Kirby-Bauer disk diffusion method. Results: The percentage of MDR isolates (resistant to at least three drug classes such as aminoglycosides, fluoroquinolones, penicillins, cephalosporins, or carbapenems) was 68% in the inpatients and 61% in the outpatients. Antibiotic resistance to ampicillin, ceftazidim, nalidixic acid, and trimethoprim/sulfamethoxazole were higher than 50%. Amikacin, nitrofurantoin, and gentamicin showed markedly greater activity (89.1%, 85.9%, and 82.4% sensitivity, respectively) than other antimicrobial agents. Resistance to meropenem did show either in outpatients or in inpatients. Interpretation and Conclusions: The high prevalence of drug resistance among UTI patients calls for continuous monitoring of the incidence of drug resistance for appropriate empiric selection of antibiotic therapy. Empirical treatment of UTIs should be relied on susceptibility patterns from local studies. PMID:27003964

  6. The Antibiotic Susceptibility Patterns of Uropathogenic Escherichia Coli, With Special Reference to the Fluoroquinolones

    PubMed Central

    Shariff V A, Abdul Rahaman; Shenoy M, Suchitra; Yadav, Taruna; M, Radhakrishna

    2013-01-01

    Context: The emergence of drug resistance to trimethoprim-sulfamethoxazole, the penicillins, cephalosporins, and fluoroquinolones by Uropathogenic Escherichia coli (UPEC) has limited the options for selecting the appropriate antibiotic for the treatment of urinary tract infections. Aims: The The E. coli isolates, which were obtained from the culture of urine samples,were studied for their antibiotic resistance patterns, with special reference to the antimicrobial activity of the fluoroquinolones and the production of the extended spectrum β-lactamases. (ESBL), Settings and Design: This was a hospital based, prospective study which was done for a period of eighteen months. Material and Methods: This study was done by using the standard culture techniques for urine samples, the modified Kirby-Bauer disk diffusion method for the antibiotic susceptibility testing and the disk diffusion method to confirm the ESBL production by the clinical isolates of E. coli in urine. The sensitivity pattern was correlated with the clinical condition and the presence of the risk factors. The statistical analysis which was used: The statistical analysis was done by using the proportions of sensitive, resistant and intermediates. Descriptive statistics like the total, mean and percentage were done by using the Statistical Package for the Social Sciences (SPSS), version 15.0. Results: The hospital isolates showed high degrees of resistance to the penicillins, cephalosporins, nalidixic acid and the fluoroquinolones, with 59% of the isolates being ESBL producers. Conclusions: The incidence of the multidrug resistant strains of Escherichia coli has been steadily increasing over the past few years. The knowledge on the resistance pattern of the bacterial strains in a geographical area will help in guiding the appropriate and the judicious use of antibiotics. Also, the formulation of an appropriate hospital antibiotic policy will go a long way in controlling these infections. PMID:23905095

  7. Two pathogenicity islands in uropathogenic Escherichia coli J96: cosmid cloning and sample sequencing.

    PubMed

    Swenson, D L; Bukanov, N O; Berg, D E; Welch, R A

    1996-09-01

    Many of the virulence genes of pathogenic strains of Escherichia coli are carried in large multigene chromosomal segments called pathogenicity islands (PAIs) that are absent from normal fecal and laboratory K-12 strains of this bacterium. We are studying PAIs in order to better understand factors that govern virulence and to assess how such DNA segments are gained or lost during evolution. The isolation and sample sequencing of a set of 11 cosmid clones that cover all of one and much of a second large PAI in the uropathogenic E. coli J96 are described. These PAIs were mapped to the 64- and 94-min regions of the E. coli K-12 chromosome, which differ from the locations of three PAIs identified in other pathogenic E. coli strains. Analysis of the junction sequences with E. coli K-12-like DNAs showed that the insert at 94 min is within the 3' end of a phenylalanine tRNA gene, pheR, and is flanked by a 135-bp imperfect direct repeat. Analysis of the one junction recovered from the insert at 64 min indicated that it lies near another tRNA gene, pheV. To identify possible genes unique to these PAIs, 100 independent subclones of the cosmids were made by PstI digestion and ligation into a pBS+ plasmid and used in one-pass sample DNA sequencing from primer binding sites at the cloning site in the vector DNA. Database searches of the J96 PAI-specific sequences identified numerous instances in which the cloned DNAs shared significant sequence similarities to adhesins, toxins, and other virulence determinants of diverse pathogens. Several likely insertion sequence elements (IS100, IS630, and IS911) and conjugative R1 plasmid and P4 phage genes were also found. We propose that such mobile genetic elements may have facilitated the spread of virulence determinants within PAIs among bacteria.

  8. Cranberry (Vaccinium macrocarpon) oligosaccharides decrease biofilm formation by uropathogenic Escherichia coli

    PubMed Central

    Sun, Jiadong; Marais, Jannie P. J.; Khoo, Christina; LaPlante, Kerry; Vejborg, Rebecca M.; Givskov, Michael; Tolker-Nielsen, Tim; Seeram, Navindra P.; Rowley, David C.

    2015-01-01

    The preventive effects of the American cranberry (Vaccinium macrocarpon) against urinary tract infections are supported by extensive studies which have primarily focused on its phenolic constituents. Herein, a phenolic-free carbohydrate fraction (designated cranf1b-F2) was purified from cranberry fruit using ion exchange and size exclusion chromatography. MALDI-TOF-MS analysis revealed that the cranf1b-F2 constituents are predominantly oligosaccharides possessing various degrees of polymerisation and further structural analysis (by GC-MS and NMR) revealed mainly xyloglucan and arabinan residues. In antimicrobial assays, cranf1b-F2 (at 1.25 mg/mL concentration) reduced biofilm production by the uropathogenic Escherichia coli CFT073 strain by over 50% but did not inhibit bacterial growth. Cranf1b-F2 (ranging from 0.625 - 10 mg/mL) also inhibited biofilm formation of the non-pathogenic E. coli MG1655 strain up to 60% in a concentration-dependent manner. These results suggest that cranberry oligosaccharides, in addition to its phenolic constituents, may play a role in its preventive effects against urinary tract infections. PMID:26613004

  9. Environmental phosphate differentially affects virulence phenotypes of uropathogenic Escherichia coli isolates causative of prostatitis.

    PubMed

    Grillo-Puertas, M; Martínez-Zamora, M G; Rintoul, M R; Soto, S M; Rapisarda, V A

    2015-01-01

    K-12 Escherichia coli cells grown in static media containing a critical phosphate (Pi) concentration ≥25 mM maintained a high polyphosphate (polyP) level in stationary phase, impairing biofilm formation, a phenomenon that is triggered by polyP degradation. Pi concentration in human urine fluctuates according to health state. Here, the influence of environmental Pi concentration on the occurrence of virulence traits in uropathogenic E. coli (UPEC) isolated from acute prostatitis patients was evaluated. After a first screening, 3 isolates were selected according to differential biofilm formation profiles depending on media Pi concentration. For each isolate, biofilm positive and negative conditions were established. Regardless of the isolate, biofilm formation capacity was accompanied with curli and cellulose production and expression of some key virulence factors associated with adhesion. When the selected isolates were grown in their non-biofilm-forming condition, low concentrations of nalidixic acid and ciprofloxacin induced biofilm formation. Interestingly, similar to laboratory strains, polyP degradation induced biofilm formation in the selected isolates. Data demonstrated the complexity of UPEC responses to environmental Pi and the importance of polyP metabolism in the virulence of clinical isolates. PMID:26083279

  10. Alkaloids Modulate Motility, Biofilm Formation and Antibiotic Susceptibility of Uropathogenic Escherichia coli

    PubMed Central

    Dusane, Devendra H.; Hosseinidoust, Zeinab; Asadishad, Bahareh; Tufenkji, Nathalie

    2014-01-01

    Alkaloid-containing natural compounds have shown promise in the treatment of microbial infections. However, practical application of many of these compounds is pending a mechanistic understanding of their mode of action. We investigated the effect of two alkaloids, piperine (found in black pepper) and reserpine (found in Indian snakeroot), on the ability of the uropathogenic bacterium Escherichia coli CFT073 to colonize abiotic surfaces. Sub-inhibitory concentrations of both compounds (0.5 to 10 µg/mL) decreased bacterial swarming and swimming motilities and increased biofilm formation. qRT-PCR revealed a decrease in the expression of the flagellar gene (fliC) and motility genes (motA and motB) along with an increased expression of adhesin genes (fimA, papA, uvrY). Interestingly, piperine increased penetration of the antibiotics ciprofloxacin and azithromycin into E. coli CFT073 biofilms and consequently enhanced the ability of these antibiotics to disperse pre-established biofilms. The findings suggest that these alkaloids can potentially affect bacterial colonization by hampering bacterial motility and may aid in the treatment of infection by increasing antibiotic penetration in biofilms. PMID:25391152

  11. Environmental phosphate differentially affects virulence phenotypes of uropathogenic Escherichia coli isolates causative of prostatitis

    PubMed Central

    Grillo-Puertas, M; Martínez-Zamora, MG; Rintoul, MR; Soto, SM; Rapisarda, VA

    2015-01-01

    K-12 Escherichia coli cells grown in static media containing a critical phosphate (Pi) concentration ≥25 mM maintained a high polyphosphate (polyP) level in stationary phase, impairing biofilm formation, a phenomenon that is triggered by polyP degradation. Pi concentration in human urine fluctuates according to health state. Here, the influence of environmental Pi concentration on the occurrence of virulence traits in uropathogenic E. coli (UPEC) isolated from acute prostatitis patients was evaluated. After a first screening, 3 isolates were selected according to differential biofilm formation profiles depending on media Pi concentration. For each isolate, biofilm positive and negative conditions were established. Regardless of the isolate, biofilm formation capacity was accompanied with curli and cellulose production and expression of some key virulence factors associated with adhesion. When the selected isolates were grown in their non-biofilm-forming condition, low concentrations of nalidixic acid and ciprofloxacin induced biofilm formation. Interestingly, similar to laboratory strains, polyP degradation induced biofilm formation in the selected isolates. Data demonstrated the complexity of UPEC responses to environmental Pi and the importance of polyP metabolism in the virulence of clinical isolates. PMID:26083279

  12. Characterization and zoonotic potential of uropathogenic Escherichia coli isolated from dogs.

    PubMed

    Nam, Eui-Hwa; Ko, Sungjin; Chae, Joon-Seok; Hwang, Cheol-Yong

    2013-03-01

    The aim of this study was to investigate the characteristics of canine uropathogenic Escherichia coli (UPEC) and the interaction between canine UPEC and human bladder epithelial cells. Ten E. coli isolates collected from dogs with cystitis were analyzed for antimicrobial resistance patterns, the presence of virulence factors, and biofilm formation. The ability of these isolates to induce cytotoxicity, invade human bladder epithelial cells, and stimulate an immune response was also determined. We observed a high rate of antimicrobial resistance among canine UPEC isolates. All virulence genes tested (including adhesins, iron acquisition, and protectin), except toxin genes, were detected among the canine UPEC isolates. We found that all isolates showed varying degrees of biofilm formation (mean, 0.26; range, 0.07 to 0.82), using a microtiter plate assay to evaluate biofilm formation by the isolates. Cytotoxicity to human bladder epithelial cells by the canine UPEC isolates increased in a time-dependent manner, with a 56.9% and 36.1% reduction in cell viability compared with the control at 6 and 9 h of incubation, respectively. We found that most canine UPEC isolates were able to invade human bladder epithelial cells. The interaction between these isolates and human bladder epithelial cells strongly induced the production of proinflammatory cytokines such as IL-6 and IL-8. We demonstrated that canine UPEC isolates can interact with human bladder epithelial cells, although the detailed mechanisms remain unknown. The results suggest that canine UPEC isolates, rather than dogspecific pathogens, have zoonotic potential.

  13. Possible involvement of Mycoplasma hominis in inhibiting the formation of biofilms by uropathogenic Escherichia coli (UPEC).

    PubMed

    Oh, Sangnam; Go, Gwang-Woong; Choi, Nag-Jin; Oh, Sejong; Kim, Younghoon

    2013-01-01

    Here we examined the involvement of Mycoplasma hominis in the formation of biofilms by uropathogenic Escherichia coli (UPEC) strain CFT073. Initially, we thought that M. hominis does not affect the fitness of UPEC, including the growth and production of signaling molecules, such as autoinducer-2 and indole. We found, however, that the presence of M. hominis significantly decreased the degree of biofilm formation by UPEC CFT073 (approximately a 60% reduction for 10(5) ccu/mL of M. hominis as compared with UPEC alone). We also found that it had a slight effect in inhibiting the attachment and cytotoxicity of UPEC CFT073. These findings are specific to these UPEC strains rather than to enterohemorrhagic E. coli (EHEC) strains, found in normal intestinal flora. In addition, we performed whole-transcriptome profiling and quantitative real-time polymerase chain reaction (qRT-PCR) analysis. This indicated that the PhoPQ system and the anti-termination protein (encoded by ybcQ) were involved in the reduction of biofilm formation by M. hominis (corroborated by qRT-PCR). Furthermore, our results indicate that M. hominis raises the degree of transcription of toxin genes, including hha and pasT. Hence, we suggest a possible role of M. hominis in affecting the formation of biofilms by UPEC in the urinary tract.

  14. Role of uropathogenic Escherichia coli OmpT in the resistance against human cathelicidin LL-37.

    PubMed

    Brannon, John R; Thomassin, Jenny-Lee; Desloges, Isabelle; Gruenheid, Samantha; Le Moual, Hervé

    2013-08-01

    Uropathogenic Escherichia coli (UPEC) strains are among the most prevalent causative agents of urinary tract infections. To establish infection, UPEC must overcome the bactericidal action of host antimicrobial peptides. Previously, the enterohaemorrhagic E. coli outer membrane protease, OmpT, was shown to degrade and inactivate the human antimicrobial peptide LL-37. This study aims to investigate the involvement of UPEC OmpT in LL-37 degradation. An ompT deletion mutant was generated in the prototypical UPEC strain CFT073. Western blot analysis showed that the OmpT protein level is moderate in CFT073. In agreement, OmpT was shown to partially cleave LL-37. However, no difference in the minimum inhibitory concentration of LL-37 was observed between CFT073 and the ompT mutant. Plasmid complementation of ompT, which led to increased OmpT levels, resulted in complete cleavage of LL-37 and a fourfold increase in the minimum inhibitory concentration. The analysis of other UPEC isolates showed similar OmpT activity levels as CFT073. Although UPEC OmpT can cleave LL-37, we conclude that the low level of OmpT limits its contribution to LL-37 resistance. Collectively, these data suggest that UPEC OmpT is likely accompanied by other LL-37 resistance mechanisms.

  15. Uropathogenic Escherichia coli Modulates Innate Immunity To Suppress Th1-Mediated Inflammatory Responses during Infectious Epididymitis

    PubMed Central

    Lang, Tali; Hudemann, Christoph; Tchatalbachev, Svetlin; Stammler, Angelika; Michel, Vera; Aslani, Ferial; Bhushan, Sudhanshu; Chakraborty, Trinad; Renz, Harald

    2014-01-01

    Infectious epididymitis in men, a frequent entity in urological outpatient settings, is commonly caused by bacteria originating from the anal region ascending the genitourinary tract. One of the most prevalent pathogens associated with epididymitis is Escherichia coli. In our previous study, we showed that semen quality is compromised in men following epididymitis associated with specific E. coli pathovars. Thus, our aim was to investigate possible differences in immune responses elicited during epididymitis following infection with the uropathogenic E. coli (UPEC) strain CFT073 and the nonpathogenic enteric E. coli (NPEC) strain 470. Employing an in vivo experimental epididymitis model, C57BL/6 mice were infected with UPEC CFT073, NPEC 470, or phosphate-buffered saline (PBS) as a sham control for up to 7 days. After infection with NPEC 470, the expression of proinflammatory cytokines interleukin-1 (IL-1), IL-6, and tumor necrosis factor alpha in the epididymis was significantly increased. Conversely, UPEC CFT073-challenged mice displayed inflammatory gene expression at levels comparable to sham PBS-treated animals. Moreover, by day 7 only NPEC-infected animals showed activation of adaptive immunity evident by a substantial influx of CD3+ and F4/80+ cells in the epididymal interstitium. This correlated with enhanced production of Th1-associated cytokines IL-2 and gamma interferon (IFN-γ). Furthermore, splenocytes isolated from UPEC-infected mice exhibited diminished T-cell responses with significantly reduced secretion of IL-2 and IFN-γ in contrast to NPEC-infected animals. Overall, these findings provide new insights into understanding pathogen-specific modulation of host immunity during acute phases of epididymitis, which may influence severity of disease and clinical outcomes. PMID:24366252

  16. How to become a uropathogen: Comparative genomic analysis of extraintestinal pathogenic Escherichia coli strains

    PubMed Central

    Brzuszkiewicz, Elzbieta; Brüggemann, Holger; Liesegang, Heiko; Emmerth, Melanie; Ölschläger, Tobias; Nagy, Gábor; Albermann, Kaj; Wagner, Christian; Buchrieser, Carmen; Emődy, Levente; Gottschalk, Gerhard; Hacker, Jörg; Dobrindt, Ulrich

    2006-01-01

    Uropathogenic Escherichia coli (UPEC) strain 536 (O6:K15:H31) is one of the model organisms of extraintestinal pathogenic E. coli (ExPEC). To analyze this strain's genetic basis of urovirulence, we sequenced the entire genome and compared the data with the genome sequence of UPEC strain CFT073 (O6:K2:H1) and to the available genomes of nonpathogenic E. coli strain MG1655 (K-12) and enterohemorrhagic E. coli. The genome of strain 536 is ≈292 kb smaller than that of strain CFT073. Genomic differences between both UPEC are mainly restricted to large pathogenicity islands, parts of which are unique to strain 536 or CFT073. Genome comparison underlines that repeated insertions and deletions in certain parts of the genome contribute to genome evolution. Furthermore, 427 and 432 genes are only present in strain 536 or in both UPEC, respectively. The majority of the latter genes is encoded within smaller horizontally acquired DNA regions scattered all over the genome. Several of these genes are involved in increasing the pathogens' fitness and adaptability. Analysis of virulence-associated traits expressed in the two UPEC O6 strains, together with genome comparison, demonstrate the marked genetic and phenotypic variability among UPEC. The ability to accumulate and express a variety of virulence-associated genes distinguishes ExPEC from many commensals and forms the basis for the individual virulence potential of ExPEC. Accordingly, instead of a common virulence mechanism, different ways exist among ExPEC to cause disease. PMID:16912116

  17. How to become a uropathogen: comparative genomic analysis of extraintestinal pathogenic Escherichia coli strains.

    PubMed

    Brzuszkiewicz, Elzbieta; Brüggemann, Holger; Liesegang, Heiko; Emmerth, Melanie; Olschläger, Tobias; Nagy, Gábor; Albermann, Kaj; Wagner, Christian; Buchrieser, Carmen; Emody, Levente; Gottschalk, Gerhard; Hacker, Jörg; Dobrindt, Ulrich

    2006-08-22

    Uropathogenic Escherichia coli (UPEC) strain 536 (O6:K15:H31) is one of the model organisms of extraintestinal pathogenic E. coli (ExPEC). To analyze this strain's genetic basis of urovirulence, we sequenced the entire genome and compared the data with the genome sequence of UPEC strain CFT073 (O6:K2:H1) and to the available genomes of nonpathogenic E. coli strain MG1655 (K-12) and enterohemorrhagic E. coli. The genome of strain 536 is approximately 292 kb smaller than that of strain CFT073. Genomic differences between both UPEC are mainly restricted to large pathogenicity islands, parts of which are unique to strain 536 or CFT073. Genome comparison underlines that repeated insertions and deletions in certain parts of the genome contribute to genome evolution. Furthermore, 427 and 432 genes are only present in strain 536 or in both UPEC, respectively. The majority of the latter genes is encoded within smaller horizontally acquired DNA regions scattered all over the genome. Several of these genes are involved in increasing the pathogens' fitness and adaptability. Analysis of virulence-associated traits expressed in the two UPEC O6 strains, together with genome comparison, demonstrate the marked genetic and phenotypic variability among UPEC. The ability to accumulate and express a variety of virulence-associated genes distinguishes ExPEC from many commensals and forms the basis for the individual virulence potential of ExPEC. Accordingly, instead of a common virulence mechanism, different ways exist among ExPEC to cause disease.

  18. Virulence Factors and O-Serogroups Profiles of Uropathogenic Escherichia Coli Isolated from Iranian Pediatric Patients

    PubMed Central

    Dormanesh, Banafshe; Safarpoor Dehkordi, Farhad; Hosseini, Sahar; Momtaz, Hassan; Mirnejad, Reza; Hoseini, Mohammad Javad; Yahaghi, Emad; Tarhriz, Vahideh; Khodaverdi Darian, Ebrahim

    2014-01-01

    Background: Uropathogenic Escherichia coli O- Serogroups with their virulence factors are the most prevalent causes of UTIs. Objectives: The present investigation was performed to study the virulence factors and O-Serogroups profiles of UPEC isolated from Iranian pediatric patients. Patients and Methods: This cross sectional investigation was performed on 100 urine samples collected from hospitalized pediatrics of Baqiyatallah Hospital, Tehran, Iran. Midstream urine was collected to decrease potential bacterial, cellular and artifactual contamination. All samples were cultured and those with positive results were subjected to polymerase chain reactions to detect pap, cnf1, afa, sfa and hlyA genes and various O- Serogroups. Results: We found that 37.5% of boys and 75% of girls had positive results for Escherichia coli. We also found that O1 (19.33%), O2 (13.33%), O6 (13.33%), O4 (11.66%), and O18 (11.66 %) were the most commonly detected Serogroups. Totally, the serogroup of 5% of all strains were not detected. In addition, all of these O- Serogroups were pap+, cnf1+, hlyA+, and afa+. Totally, pap (70 %), cnf1 (56.66 %), and hlyA (43.33 %) were the most commonly detected virulence genes in the both studied groups of children. The sfa (30 %) and afa (26.66 %) genes had the lowest incidence rates. Conclusions: Special health care should be performed on UTIs management in Iranian pediatric patients. Extended researches should be performed to evaluate relation between other O-Serogroups and virulent genes. PMID:24719745

  19. Comparison of adhesin genes and antimicrobial susceptibilities between uropathogenic and intestinal commensal Escherichia coli strains.

    PubMed

    Qin, Xiaohua; Hu, Fupin; Wu, Shi; Ye, Xinyu; Zhu, Demei; Zhang, Ying; Wang, Minggui

    2013-01-01

    The presence of adhesins is arguably an important determinant of pathogenicity for Uropathogenic Escherichia coli (UPEC). Antimicrobial susceptibilities were tested by agar dilution method, fifteen adhesin genes were detected by polymerase chain reaction, and multilocus sequence typing (MLST) was analyzed in 70 UPEC isolates and 41 commensal E. coli strains. Extended-spectrum β-lactamase (ESBL) was determined with confirmatory test. The prevalence of ESBL-producers in UPEC (53%, 37/70) was higher than the commensal intestinal isolates (7%, 3/41), and 97% (36/37) of the ESBL-producing UPEC harbored bla CTX-M genes. afa was present in 36% (10/28) UPEC isolates from recurrent lower urinary tract infection (UTI), and none in the acute pyelonephritis, acute uncomplicated cystitis or commensal strains (P<0.0001). papG was detected in 28% (20/70) of UPEC isolates, while 5% (2/41) of the commensal strains were papG positive (P = 0.0025), and the prevalence of papG was significantly higher in acute pyelonephritis group (71%) than the other two UTI groups (P<0.0001). The prevalence of flu, yqi, yadN and ygiL was significantly higher in UPEC isolates than in the commensal strains. ESBL-producing UPEC showed a lower prevalence of adhesin genes compared with non-ESBL-producing strains. The MLST profiles were different between UPEC and commensal strains, with ST131 (19%, 13/70) and ST10 (20%, 8/41) being the most common MLSTs, respectively. This study demonstrated that several adhesin genes were more prevalent in UPEC isolates than in commensal E. coli, and afa may be associated with recurrent lower UTI whereas papG is more frequently associated with acute pyelonephritis.

  20. YbcL of uropathogenic Escherichia coli suppresses transepithelial neutrophil migration.

    PubMed

    Lau, Megan E; Loughman, Jennifer A; Hunstad, David A

    2012-12-01

    Uropathogenic Escherichia coli (UPEC) strains suppress the acute inflammatory response in the urinary tract to ensure access to the intracellular uroepithelial niche that supports the propagation of infection. Our understanding of this initial cross talk between host and pathogen is incomplete. Here we report the identification of a previously uncharacterized periplasmic protein, YbcL, encoded by UPEC that contributes to immune modulation in the urinary tract by suppressing acute neutrophil migration. In contrast to wild-type UPEC, an isogenic strain lacking ybcL expression (UTI89 ΔybcL) failed to suppress transepithelial polymorphonuclear leukocyte (PMN) migration in vitro, a defect complemented by expressing ybcL episomally. YbcL homologs are present in many E. coli genomes; expression of the YbcL variant encoded by nonpathogenic E. coli K-12 strain MG1655 (YbcL(MG)) failed to complement the UTI89 ΔybcL defect, whereas expression of the UPEC YbcL variant (YbcL(UTI)) in MG1655 conferred the capacity for suppressing PMN migration. This phenotypic difference was due to a single amino acid difference (V78T) between the two YbcL homologs, and a majority of clinical UPEC strains examined were found to encode the suppressive YbcL variant. Purified YbcL(UTI) protein suppressed PMN migration in response to live or killed MG1655, and YbcL(UTI) was detected in the supernatant during UPEC infection of bladder epithelial cells or PMNs. Lastly, early PMN influx to murine bladder tissue was augmented upon in vivo infection with UTI89 ΔybcL compared with wild-type UPEC. Our findings demonstrate a role for UPEC YbcL in suppression of the innate immune response during urinary tract infection.

  1. Phenotypic heterogeneity enables uropathogenic Escherichia coli to evade killing by antibiotics and serum complement.

    PubMed

    Putrinš, Marta; Kogermann, Karin; Lukk, Eliisa; Lippus, Markus; Varik, Vallo; Tenson, Tanel

    2015-03-01

    Uropathogenic strains of Escherichia coli (UPEC) are the major cause of bacteremic urinary tract infections. Survival in the bloodstream is associated with different mechanisms that help to resist serum complement-mediated killing. While the phenotypic heterogeneity of bacteria has been shown to influence antibiotic tolerance, the possibility that it makes cells refractory to killing by the immune system has not been experimentally tested. In the present study we sought to determine whether the heterogeneity of bacterial cultures is relevant to bacterial targeting by the serum complement system. We monitored cell divisions in the UPEC strain CFT073 with fluorescent reporter protein. Stationary-phase cells were incubated in active or heat-inactivated human serum in the presence or absence of different antibiotics (ampicillin, norfloxacin, and amikacin), and cell division and complement protein C3 binding were measured by flow cytometry and immunofluorescence microscopy. Heterogeneity in the doubling times of CFT073 cells in serum enabled three phenotypically different subpopulations to be distinguished, all of them being recognized by the C3 component of the complement system. The population of rapidly growing cells resists serum complement-mediated lysis. The dominant subpopulation of cells with intermediate growth rate is susceptible to serum. The third population, which does not resume growth upon dilution from stationary phase, is simultaneously protected from serum complement and antibiotics.

  2. Subinhibitory Concentrations of Allicin Decrease Uropathogenic Escherichia coli (UPEC) Biofilm Formation, Adhesion Ability, and Swimming Motility.

    PubMed

    Yang, Xiaolong; Sha, Kaihui; Xu, Guangya; Tian, Hanwen; Wang, Xiaoying; Chen, Shanze; Wang, Yi; Li, Jingyu; Chen, Junli; Huang, Ning

    2016-01-01

    Uropathogenic Escherichia coli (UPEC) biofilm formation enables the organism to avoid the host immune system, resist antibiotics, and provide a reservoir for persistent infection. Once the biofilm is established, eradication of the infection becomes difficult. Therefore, strategies against UPEC biofilm are urgently required. In this study, we investigated the effect of allicin, isolated from garlic essential oil, on UPEC CFT073 and J96 biofilm formation and dispersal, along with its effect on UPEC adhesion ability and swimming motility. Sub-inhibitory concentrations (sub-MICs) of allicin decreased UPEC biofilm formation and affected its architecture. Allicin was also capable of dispersing biofilm. Furthermore, allicin decreased the bacterial adhesion ability and swimming motility, which are important for biofilm formation. Real-time quantitative polymerase chain reaction (RT-qPCR) revealed that allicin decreased the expression of UPEC type 1 fimbriae adhesin gene fimH. Docking studies suggested that allicin was located within the binding pocket of heptyl α-d-mannopyrannoside in FimH and formed hydrogen bonds with Phe1 and Asn135. In addition, allicin decreased the expression of the two-component regulatory systems (TCSs) cognate response regulator gene uvrY and increased the expression of the RNA binding global regulatory protein gene csrA of UPEC CFT073, which is associated with UPEC biofilm. The findings suggest that sub-MICs of allicin are capable of affecting UPEC biofilm formation and dispersal, and decreasing UPEC adhesion ability and swimming motility. PMID:27367677

  3. Local Generation of Kynurenines Mediates Inhibition of Neutrophil Chemotaxis by Uropathogenic Escherichia coli

    PubMed Central

    Loughman, Jennifer A.; Yarbrough, Melanie L.; Tiemann, Kristin M.

    2016-01-01

    During epithelial infections, pathogenic bacteria employ an array of strategies to attenuate and evade host immune responses, including the influx of polymorphonuclear leukocytes (PMN; neutrophils). Among the most common bacterial infections in humans are those of the urinary tract, caused chiefly by uropathogenic Escherichia coli (UPEC). During the establishment of bacterial cystitis, UPEC suppresses innate responses via multiple independent strategies. We recently described UPEC attenuation of PMN trafficking to the urinary bladder through pathogen-specific local induction of indoleamine 2,3-dioxygenase (IDO), a tryptophan catabolic enzyme previously shown to have regulatory activity only in adaptive immunity. Here, we investigated the mechanism by which IDO induction attenuates PMN migration. Local tryptophan limitation, by which IDO is known to influence T cell longevity and proliferation, was not involved in its effect on PMN trafficking. Instead, metabolites in the IDO pathway, particularly l-kynurenine, directly suppressed PMN transepithelial migration and induced an attached, spread morphology in PMN both at rest and in the presence of chemotactic stimuli. Finally, kynurenines represent known ligands of the mammalian aryl hydrocarbon receptor (AHR), and UPEC infection of Ahr−/− mice recapitulated the derepressed PMN recruitment observed previously in Ido1−/− mice. UPEC therefore suppresses neutrophil migration early in bacterial cystitis by eliciting an IDO-mediated increase in local production of kynurenines, which act through the AHR to impair neutrophil chemotaxis. PMID:26857571

  4. Uropathogenic Escherichia coli virulence genes: invaluable approaches for designing DNA microarray probes

    PubMed Central

    Jahandeh, Nadia; Ranjbar, Reza; Behzadi, Elham

    2015-01-01

    Introduction The pathotypes of uropathogenic Escherichia coli (UPEC) cause different types of urinary tract infections (UTIs). The presence of a wide range of virulence genes in UPEC enables us to design appropriate DNA microarray probes. These probes, which are used in DNA microarray technology, provide us with an accurate and rapid diagnosis and definitive treatment in association with UTIs caused by UPEC pathotypes. The main goal of this article is to introduce the UPEC virulence genes as invaluable approaches for designing DNA microarray probes. Material and methods Main search engines such as Google Scholar and databases like NCBI were searched to find and study several original pieces of literature, review articles, and DNA gene sequences. In parallel with in silico studies, the experiences of the authors were helpful for selecting appropriate sources and writing this review article. Results There is a significant variety of virulence genes among UPEC strains. The DNA sequences of virulence genes are fabulous patterns for designing microarray probes. The location of virulence genes and their sequence lengths influence the quality of probes. Conclusions The use of selected virulence genes for designing microarray probes gives us a wide range of choices from which the best probe candidates can be chosen. DNA microarray technology provides us with an accurate, rapid, cost-effective, sensitive, and specific molecular diagnostic method which is facilitated by designing microarray probes. Via these tools, we are able to have an accurate diagnosis and a definitive treatment regarding UTIs caused by UPEC pathotypes. PMID:26855801

  5. Waging War against Uropathogenic Escherichia coli: Winning Back the Urinary Tract▿

    PubMed Central

    Sivick, Kelsey E.; Mobley, Harry L. T.

    2010-01-01

    Urinary tract infection (UTI) caused by uropathogenic Escherichia coli (UPEC) is a substantial economic and societal burden—a formidable public health issue. Symptomatic UTI causes significant discomfort in infected patients, results in lost productivity, predisposes individuals to more serious infections, and usually necessitates antibiotic therapy. There is no licensed vaccine available for prevention of UTI in humans in the United States, likely due to the challenge of targeting a relatively heterogeneous group of pathogenic strains in a unique physiological niche. Despite significant advances in the understanding of UPEC biology, mechanistic details regarding the host response to UTI and full comprehension of genetic loci that influence susceptibility require additional work. Currently, there is an appreciation for the role of classic innate immune responses—from pattern receptor recognition to recruitment of phagocytic cells—that occur during UPEC-mediated UTI. There is, however, a clear disconnect regarding how factors involved in the innate immune response to UPEC stimulate acquired immunity that facilitates enhanced clearance upon reinfection. Unraveling the molecular details of this process is vital in the development of a successful vaccine for prevention of human UTI. Here, we survey the current understanding of host responses to UPEC-mediated UTI with an eye on molecular and cellular factors whose activity may be harnessed by a vaccine that stimulates lasting and sterilizing immunity. PMID:19917708

  6. Human milk oligosaccharides protect bladder epithelial cells against uropathogenic Escherichia coli invasion and cytotoxicity.

    PubMed

    Lin, Ann E; Autran, Chloe A; Espanola, Sophia D; Bode, Lars; Nizet, Victor

    2014-02-01

    The invasive pathogen uropathogenic Escherichia coli (UPEC) is the primary cause of urinary tract infections (UTIs). Recurrent infection that can progress to life-threatening renal failure has remained as a serious global health concern in infants. UPEC adheres to and invades bladder epithelial cells to establish infection. Studies have detected the presence of human milk oligosaccharides (HMOs) in urine of breast-fed, but not formula-fed, neonates. We investigated the mechanisms HMOs deploy to elicit protection in human bladder epithelial cells infected with UPEC CFT073, a prototypic urosepsis-associated strain. We found a significant reduction in UPEC internalization into HMO-pretreated epithelial cells without observing any significant effect in UPEC binding to these cells. This event coincides with a rapid decrease in host cell cytotoxicity, recognized by LIVE/DEAD staining and cell detachment, but independent of caspase-mediated or mitochondrial-mediated programmed cell death pathways. Further investigation revealed HMOs, and particularly the sialic acid-containing fraction, reduced UPEC-mediated MAPK and NF-κB activation. Collectively, our results indicate that HMOs can protect bladder epithelial cells from deleterious cytotoxic and proinflammatory effects of UPEC infection, and may be one contributing mechanism underlying the epidemiological evidence of reduced UTI incidence in breast-fed infants.

  7. Subinhibitory Concentrations of Allicin Decrease Uropathogenic Escherichia coli (UPEC) Biofilm Formation, Adhesion Ability, and Swimming Motility.

    PubMed

    Yang, Xiaolong; Sha, Kaihui; Xu, Guangya; Tian, Hanwen; Wang, Xiaoying; Chen, Shanze; Wang, Yi; Li, Jingyu; Chen, Junli; Huang, Ning

    2016-06-29

    Uropathogenic Escherichia coli (UPEC) biofilm formation enables the organism to avoid the host immune system, resist antibiotics, and provide a reservoir for persistent infection. Once the biofilm is established, eradication of the infection becomes difficult. Therefore, strategies against UPEC biofilm are urgently required. In this study, we investigated the effect of allicin, isolated from garlic essential oil, on UPEC CFT073 and J96 biofilm formation and dispersal, along with its effect on UPEC adhesion ability and swimming motility. Sub-inhibitory concentrations (sub-MICs) of allicin decreased UPEC biofilm formation and affected its architecture. Allicin was also capable of dispersing biofilm. Furthermore, allicin decreased the bacterial adhesion ability and swimming motility, which are important for biofilm formation. Real-time quantitative polymerase chain reaction (RT-qPCR) revealed that allicin decreased the expression of UPEC type 1 fimbriae adhesin gene fimH. Docking studies suggested that allicin was located within the binding pocket of heptyl α-d-mannopyrannoside in FimH and formed hydrogen bonds with Phe1 and Asn135. In addition, allicin decreased the expression of the two-component regulatory systems (TCSs) cognate response regulator gene uvrY and increased the expression of the RNA binding global regulatory protein gene csrA of UPEC CFT073, which is associated with UPEC biofilm. The findings suggest that sub-MICs of allicin are capable of affecting UPEC biofilm formation and dispersal, and decreasing UPEC adhesion ability and swimming motility.

  8. A High-resolution Typing Assay for Uropathogenic Escherichia coli Based on Fimbrial Diversity.

    PubMed

    Ren, Yi; Palusiak, Agata; Wang, Wei; Wang, Yi; Li, Xiao; Wei, Huiting; Kong, Qingke; Rozalski, Antoni; Yao, Zhi; Wang, Quan

    2016-01-01

    Urinary tract infections (UTIs) are one of the most common bacterial infections in humans, causing cystitis, pyelonephritis, and renal failure. Uropathogenic Escherichia coli (UPEC) is the leading cause of UTIs. Accurate and rapid discrimination of UPEC lineages is useful for epidemiological surveillance. Fimbriae are necessary for the adherence of UPEC strains to host uroepithelia, and seem to be abundant and diverse in UPEC strains. By analyzing all the possible fimbrial operons in UPEC strains, we found that closely related strains had similar types of chaperone-usher fimbriae, and the diversity of fimbrial genes was higher than that of multilocus sequence typing (MLST) genes. A typing assay based on the polymorphism of four gene sequences (three fimbrial genes and one housekeeping gene) and the diversity of fimbriae present was developed. By comparison with the MLST, whole-genome sequence (WGS) and fumC/fimH typing methods, this was shown to be accurate and have high resolution, and it was also relatively inexpensive and easy to perform. The assay can supply more discriminatory information for UPEC lineages, and have the potential to be applied in epidemiological surveillance of UPEC isolates.

  9. A High-resolution Typing Assay for Uropathogenic Escherichia coli Based on Fimbrial Diversity

    PubMed Central

    Ren, Yi; Palusiak, Agata; Wang, Wei; Wang, Yi; Li, Xiao; Wei, Huiting; Kong, Qingke; Rozalski, Antoni; Yao, Zhi; Wang, Quan

    2016-01-01

    Urinary tract infections (UTIs) are one of the most common bacterial infections in humans, causing cystitis, pyelonephritis, and renal failure. Uropathogenic Escherichia coli (UPEC) is the leading cause of UTIs. Accurate and rapid discrimination of UPEC lineages is useful for epidemiological surveillance. Fimbriae are necessary for the adherence of UPEC strains to host uroepithelia, and seem to be abundant and diverse in UPEC strains. By analyzing all the possible fimbrial operons in UPEC strains, we found that closely related strains had similar types of chaperone-usher fimbriae, and the diversity of fimbrial genes was higher than that of multilocus sequence typing (MLST) genes. A typing assay based on the polymorphism of four gene sequences (three fimbrial genes and one housekeeping gene) and the diversity of fimbriae present was developed. By comparison with the MLST, whole-genome sequence (WGS) and fumC/fimH typing methods, this was shown to be accurate and have high resolution, and it was also relatively inexpensive and easy to perform. The assay can supply more discriminatory information for UPEC lineages, and have the potential to be applied in epidemiological surveillance of UPEC isolates. PMID:27199951

  10. DamX Controls Reversible Cell Morphology Switching in Uropathogenic Escherichia coli

    PubMed Central

    Khandige, Surabhi; Asferg, Cecilie Antoinette; Rasmussen, Karina Juhl; Larsen, Martin Jakob; Overgaard, Martin

    2016-01-01

    ABSTRACT The ability to change cell morphology is an advantageous characteristic adopted by multiple pathogenic bacteria in order to evade host immune detection and assault during infection. Uropathogenic Escherichia coli (UPEC) exhibits such cellular dynamics and has been shown to transition through a series of distinct morphological phenotypes during a urinary tract infection. Here, we report the first systematic spatio-temporal gene expression analysis of the UPEC transition through these phenotypes by using a flow chamber-based in vitro infection model that simulates conditions in the bladder. This analysis revealed a novel association between the cell division gene damX and reversible UPEC filamentation. We demonstrate a lack of reversible bacterial filamentation in a damX deletion mutant in vitro and absence of a filamentous response by this mutant in a murine model of cystitis. While deletion of damX abrogated UPEC filamentation and secondary surface colonization in tissue culture and in mouse infections, transient overexpression of damX resulted in reversible UPEC filamentation. In this study, we identify a hitherto-unknown damX-mediated mechanism underlying UPEC morphotypical switching. Murine infection studies showed that DamX is essential for establishment of a robust urinary tract infection, thus emphasizing its role as a mediator of virulence. Our study demonstrates the value of an in vitro methodology, in which uroepithelium infection is closely simulated, when undertaking targeted investigations that are challenging to perform in animal infection models. PMID:27486187

  11. Chloramphenicol- and tetracycline-resistant uropathogenic Escherichia coli (UPEC) exhibit reduced virulence potential.

    PubMed

    Starcic Erjavec, Marjanca; Rijavec, Matija; Krizan-Hergouth, Veronika; Fruth, Angelika; Zgur-Bertok, Darja

    2007-11-01

    It is well documented that uropathogenic Escherichia coli (UPEC) isolates resistant to nalidixic acid have reduced virulence potential. Our goal was to assess whether UPEC isolates resistant to chloramphenicol, tetracycline and streptomycin also exhibit reduced virulence potential. Among 110 human UPEC isolates, the prevalences of the virulence factors fimH, papC, papGII, papGIII, sfa/focDE, afa, hlyA, cnf1, usp, ibeA, fyuA, iroN, iucD, ireA, and K1 and K5 capsules as well as of pathotypes, phylogenetic groups, O antigens and a pathogenicity island (PAI) marker were compared between chloramphenicol-, tetracycline-, streptomycin- and, as a control, nalidixic acid-resistant and -susceptible strains. Our findings show that among human UPEC isolates, not only nalidixic acid-resistant but also chloramphenicol- and tetracycline-resistant isolates have reduced virulence potential compared with susceptible strains. To our knowledge, this is the first report of a statistically significant reduction in virulence traits among chloramphenicol- and tetracycline-resistant isolates.

  12. Subinhibitory Concentrations of Allicin Decrease Uropathogenic Escherichia coli (UPEC) Biofilm Formation, Adhesion Ability, and Swimming Motility

    PubMed Central

    Yang, Xiaolong; Sha, Kaihui; Xu, Guangya; Tian, Hanwen; Wang, Xiaoying; Chen, Shanze; Wang, Yi; Li, Jingyu; Chen, Junli; Huang, Ning

    2016-01-01

    Uropathogenic Escherichia coli (UPEC) biofilm formation enables the organism to avoid the host immune system, resist antibiotics, and provide a reservoir for persistent infection. Once the biofilm is established, eradication of the infection becomes difficult. Therefore, strategies against UPEC biofilm are urgently required. In this study, we investigated the effect of allicin, isolated from garlic essential oil, on UPEC CFT073 and J96 biofilm formation and dispersal, along with its effect on UPEC adhesion ability and swimming motility. Sub-inhibitory concentrations (sub-MICs) of allicin decreased UPEC biofilm formation and affected its architecture. Allicin was also capable of dispersing biofilm. Furthermore, allicin decreased the bacterial adhesion ability and swimming motility, which are important for biofilm formation. Real-time quantitative polymerase chain reaction (RT-qPCR) revealed that allicin decreased the expression of UPEC type 1 fimbriae adhesin gene fimH. Docking studies suggested that allicin was located within the binding pocket of heptyl α-d-mannopyrannoside in FimH and formed hydrogen bonds with Phe1 and Asn135. In addition, allicin decreased the expression of the two-component regulatory systems (TCSs) cognate response regulator gene uvrY and increased the expression of the RNA binding global regulatory protein gene csrA of UPEC CFT073, which is associated with UPEC biofilm. The findings suggest that sub-MICs of allicin are capable of affecting UPEC biofilm formation and dispersal, and decreasing UPEC adhesion ability and swimming motility. PMID:27367677

  13. Mechanisms of uropathogenic Escherichia coli persistence and eradication from the urinary tract

    PubMed Central

    Mysorekar, Indira U.; Hultgren, Scott J.

    2006-01-01

    Recurrent urinary tract infections (rUTIs) are a source of considerable morbidity in women. The infecting bacteria in both rUTIs and a de novo acute infection have been thought to originate from an extraurinary location. Here, we show in a murine model of UTI that uropathogenic Escherichia coli (UPEC) established quiescent intracellular reservoirs (QIRs) in Lamp1+ endosomes within the urinary bladder epithelium. Depending on the integrity of the urothelial barriers at the time of initial infection, these QIRs were established within terminally differentiated superficial facet cells and/or underlying transitional epithelial cells. Treatment of infected bladders harboring exclusively superficial facet cell QIRs with the cationic protein, protamine sulfate, led to epithelial exfoliation and eradication of bacteria in 100% of treated animals. However, when the bacterial QIRs were harbored in underlying transitional cells, stimulation of epithelial turnover triggered reemergence of viable organisms and recurrence of infection. Thus, our results suggest (i) that bacterial QIRs within the bladder may be a previously unappreciated source of recurrent UTIs and (ii) that inducing epithelial exfoliation may be a therapeutic avenue for treating this heretofore recalcitrant disease. PMID:16968784

  14. MOLECULAR CHARACTERIZATION OF VIRULENCE AND ANTIMICROBIAL SUSCEPTIBILITY PROFILES OF UROPATHOGENIC ESCHERICHIA COLI FROM PATIENTS IN A TERTIARY HOSPITAL, SOUTHERN THAILAND.

    PubMed

    Themphachanal, Monchanok; Kongpheng, Suttiporn; Rattanachuay, Pattamarat; Khianngam, Saowapar; Singkhamanan, Kamonnut; Sukhumungoon, Pharanai

    2015-11-01

    Among uropathogens, uropathogenic Escherichia coli (UPEC) is the most common cause of urinary tract infection (UTI) worldwide, but clinical aspects due to this bacterial species is not fully understood in southern Thailand. Two hundred fifty-four UPEC isolates from patients admitted to Maharaj Nakhon Si Thammarat Hospital, southern Thailand were examined for crucial virulence genes, showing that 33.5% contained at least one of the virulence, genes tested. Genes encoding P fimbria, cytotoxic necrotizing factor-1 and α-hemolysin constituted the majority (15.8%) carried by UPEC isolates. Phylogenetic group classification revealed that 57.5% of UPEC belonged to group D. Antimicrobial susceptibility tests showed that 70.5% and 65.1% of the isolates were resistant to ciprofloxacin and norfloxacin, respectively. Moreover, 50.0% of UPEC were capable of producing extended spectrum beta-lactamases. These findings should be of benefit for more appropriate treatment of UTI patients in this region of Thailand. Keywords: uropathogenic Escherichia coli, antibiotics resistance, cnfl, hlyA, pap, Thailand PMID:26867360

  15. MOLECULAR CHARACTERIZATION OF VIRULENCE AND ANTIMICROBIAL SUSCEPTIBILITY PROFILES OF UROPATHOGENIC ESCHERICHIA COLI FROM PATIENTS IN A TERTIARY HOSPITAL, SOUTHERN THAILAND.

    PubMed

    Themphachanal, Monchanok; Kongpheng, Suttiporn; Rattanachuay, Pattamarat; Khianngam, Saowapar; Singkhamanan, Kamonnut; Sukhumungoon, Pharanai

    2015-11-01

    Among uropathogens, uropathogenic Escherichia coli (UPEC) is the most common cause of urinary tract infection (UTI) worldwide, but clinical aspects due to this bacterial species is not fully understood in southern Thailand. Two hundred fifty-four UPEC isolates from patients admitted to Maharaj Nakhon Si Thammarat Hospital, southern Thailand were examined for crucial virulence genes, showing that 33.5% contained at least one of the virulence, genes tested. Genes encoding P fimbria, cytotoxic necrotizing factor-1 and α-hemolysin constituted the majority (15.8%) carried by UPEC isolates. Phylogenetic group classification revealed that 57.5% of UPEC belonged to group D. Antimicrobial susceptibility tests showed that 70.5% and 65.1% of the isolates were resistant to ciprofloxacin and norfloxacin, respectively. Moreover, 50.0% of UPEC were capable of producing extended spectrum beta-lactamases. These findings should be of benefit for more appropriate treatment of UTI patients in this region of Thailand. Keywords: uropathogenic Escherichia coli, antibiotics resistance, cnfl, hlyA, pap, Thailand

  16. Identification of Anti-Persister Activity against Uropathogenic Escherichia coli from a Clinical Drug Library

    PubMed Central

    Niu, Hongxia; Cui, Peng; Shi, Wanliang; Zhang, Shuo; Feng, Jie; Wang, Yong; Sullivan, David; Zhang, Wenhong; Zhu, Bingdong; Zhang, Ying

    2015-01-01

    Uropathogenic E. coli is a major cause of urinary tract infections (UTIs), but current antibiotics do not always effectively clear the persistent infection. To identify drugs that eliminate uropathogenic E. coli persisters, we screened a clinical drug library consisting of 1524 compounds using high throughput drug exposure assay in 96-well plates. Bacterial survival was assessed by growth on LB plates. We identified 14 drug candidates (tosufloxacin, colistin, sparfloxacin, moxifloxacin and gatifloxacin, enrofloxacin and sarafloxacin, octodrine, clofoctol, dibekacin, cephalosporin C, pazufloxacin, streptomycin and neomycin), which had high anti-persister activity. Among them, tosufloxacin and colistin had the highest anti-persister activity and could completely eradicate E. coli persisters in 3 days in vitro while the current UTI antibiotics failed to do so. Our findings may have implications for the development of a more effective treatment for UTIs. PMID:27025620

  17. Virulence Characteristics and Antibiotic Resistance Patterns among Various Phylogenetic Groups of Uropathogenic Escherichia coli Isolates.

    PubMed

    Derakhshandeh, Abdollah; Firouzi, Roya; Motamedifar, Mohammad; Arabshahi, Sina; Novinrooz, Aytak; Boroojeni, Azar Motamedi; Bahadori, Maryam; Heidari, Susan

    2015-01-01

    The aim of this study was to determine the resistance patterns of uropathogenic Escherichia coli (UPEC) isolates and to investigate the frequency of several virulence genes, including fimH, papA, hlyD, cnf-1, sitA, and tsh, among various phylogenetic groups of UPEC isolates. A total of 85 E. coli isolates were recovered from urine samples from outpatients with a clinical diagnosis of uncomplicated urinary tract infections. A molecular approach to examine the antimicrobial resistance patterns was employed using PCR and the disc diffusion method. The detected frequencies of the virulence factor genes determined using PCR were: fimH (34.1%), papA (9.4%), hlyD (21.2%), cnf-1 (3.5%), sitA (15.3%), and tsh (27.1%). These results revealed that the isolates were resistant to trimethoprim-sulfamethoxazole (SXT) (74.1%), cefotaxime (CTX) (68.2%), and amoxicillin-clavulanic acid (AMC) (94.1%), and they were relatively less resistant to N (56.5%). According to these results, further investigation is needed to determine exactly whether or not SXT, CTX, and AMC are appropriate antibiotics for the treatment of UPEC infections in southern Iran. Although these results demonstrate that fimH is the most frequent virulence gene among UPEC isolates, the high prevalence of isolates that do not encode fimH (75.9%) and the relatively low frequency of isolates that carry other virulence genes require further investigation to clarify the role of the other potential virulence factors in the pathogenesis of these isolates.

  18. Urothelial cultures support intracellular bacterial community formation by uropathogenic Escherichia coli.

    PubMed

    Berry, Ruth E; Klumpp, David J; Schaeffer, Anthony J

    2009-07-01

    Uropathogenic Escherichia coli (UPEC) causes most community-acquired and nosocomial urinary tract infections (UTI). In a mouse model of UTI, UPEC invades superficial bladder cells and proliferates rapidly, forming biofilm-like structures called intracellular bacterial communities (IBCs). Using a gentamicin protection assay and fluorescence microscopy, we developed an in vitro model for studying UPEC proliferation within immortalized human urothelial cells. By pharmacologic manipulation of urothelial cells with the cholesterol-sequestering drug filipin, numbers of intracellular UPEC CFU increased 8 h and 24 h postinfection relative to untreated cultures. Enhanced UPEC intracellular proliferation required that the urothelial cells, but not the bacteria, be filipin treated prior to infection. However, neither UPEC frequency of invasion nor early intracellular trafficking events to a Lamp1-positive compartment were modulated by filipin. Upon inspection by fluorescence microscopy, cultures with enhanced UPEC intracellular proliferation exhibited large, dense bacterial aggregates within cells that resembled IBCs but were contained with Lamp1-positive vacuoles. While an isogenic fimH mutant was capable of forming these IBC-like structures, the mutant formed significantly fewer than wild-type UPEC. Similar to IBCs, expression of E. coli iron acquisition systems was upregulated by intracellular UPEC. Expression of other putative virulence factors, including hlyA, cnf1, fliC, kpsD, and the biofilm adhesin yfaL also increased, while expression of fimA decreased and that of flu did not change. These results indicate that UPEC differentially regulates virulence factors in the intracellular environment. Thus, immortalized urothelial cultures that recapitulate IBC formation in vitro represent a novel system for the molecular and biochemical characterization of the UPEC intracellular life cycle.

  19. PafR, a Novel Transcription Regulator, Is Important for Pathogenesis in Uropathogenic Escherichia coli

    PubMed Central

    Baum, Mordechai; Watad, Mobarak; Smith, Sara N.; Alteri, Christopher J.; Gordon, Noa; Rosenshine, Ilan; Mobley, Harry L.

    2014-01-01

    The metV genomic island in the chromosome of uropathogenic Escherichia coli (UPEC) encodes a putative transcription factor and a sugar permease of the phosphotransferase system (PTS), which are predicted to compose a Bgl-like sensory system. The presence of these two genes, hereby termed pafR and pafP, respectively, has been previously shown to correlate with isolates causing clinical syndromes. We show here that deletion of both genes impairs the ability of the resulting mutant to infect the CBA/J mouse model of ascending urinary tract infection compared to that of the parent strain, CFT073. Expressing the two genes in trans in the two-gene knockout mutant complemented full virulence. Deletion of either gene individually generated the same phenotype as the double knockout, indicating that both pafR and pafP are important to pathogenesis. We screened numerous environmental conditions but failed to detect expression from the promoter that precedes the paf genes in vitro, suggesting that they are in vivo induced (ivi). Although PafR is shown here to be capable of functioning as a transcriptional antiterminator, its targets in the UPEC genome are not known. Using microarray analysis, we have shown that expression of PafR from a heterologous promoter in CFT073 affects expression of genes related to bacterial virulence, biofilm formation, and metabolism. Expression of PafR also inhibits biofilm formation and motility. Taken together, our results suggest that the paf genes are implicated in pathogenesis and that PafR controls virulence genes, in particular biofilm formation genes. PMID:25069986

  20. Genome-Wide Detection of Fitness Genes in Uropathogenic Escherichia coli during Systemic Infection

    PubMed Central

    Subashchandrabose, Sargurunathan; Smith, Sara N.; Spurbeck, Rachel R.; Kole, Monica M.; Mobley, Harry L. T.

    2013-01-01

    Uropathogenic Escherichia coli (UPEC) is a leading etiological agent of bacteremia in humans. Virulence mechanisms of UPEC in the context of urinary tract infections have been subjected to extensive research. However, understanding of the fitness mechanisms used by UPEC during bacteremia and systemic infection is limited. A forward genetic screen was utilized to detect transposon insertion mutants with fitness defects during colonization of mouse spleens. An inoculum comprised of 360,000 transposon mutants in the UPEC strain CFT073, cultured from the blood of a patient with pyelonephritis, was used to inoculate mice intravenously. Transposon insertion sites in the inoculum (input) and bacteria colonizing the spleen (output) were identified using high-throughput sequencing of transposon-chromosome junctions. Using frequencies of representation of each insertion mutant in the input and output samples, 242 candidate fitness genes were identified. Co-infection experiments with each of 11 defined mutants and the wild-type strain demonstrated that 82% (9 of 11) of the tested candidate fitness genes were required for optimal fitness in a mouse model of systemic infection. Genes involved in biosynthesis of poly-N-acetyl glucosamine (pgaABCD), major and minor pilin of a type IV pilus (c2394 and c2395), oligopeptide uptake periplasmic-binding protein (oppA), sensitive to antimicrobial peptides (sapABCDF), putative outer membrane receptor (yddB), zinc metallopeptidase (pqqL), a shikimate pathway gene (c1220) and autotransporter serine proteases (pic and vat) were further characterized. Here, we report the first genome-wide identification of genes that contribute to fitness in UPEC during systemic infection in a mammalian host. These fitness factors may represent targets for developing novel therapeutics against UPEC. PMID:24339777

  1. Gal-Gal binding and hemolysin phenotypes and genotypes associated with uropathogenic Escherichia coli.

    PubMed

    O'Hanley, P; Low, D; Romero, I; Lark, D; Vosti, K; Falkow, S; Schoolnik, G

    1985-08-15

    To determine whether uropathogenic strains of Escherichia coli exhibit a distinctive constellation of phenotypes, we examined 44 urinary isolates from women with radiologically normal urinary tracts and pyelonephritis, cystitis, or asymptomatic bacteriuria and 73 fecal isolates from healthy control subjects. The strains were characterized by their O serogroup, by their binding specificity (as determined by adhesins), and by their production of hemolysin and colicin V. In addition, the strains were assessed for homologous gene sequences by means of DNA-hybridization probes prepared from cistrons that encode hemolysin and the Gal-Gal binding adhesin--two determinants of virulence, which cause tissue injury and promote bacterial colonization of uroepithelia, respectively. In contrast to most isolates from normal feces and from the urine of patients with asymptomatic bacteriuria, pyelonephritis strains belong to a small number of O serogroups; all express the Gal--Gal binding adhesin and 75 per cent are hemolytic. A gene probe for the Gal--Gal binding adhesin, derived from the chromosome of one strain from a patient with pyelonephritis, hybridized with the DNA of all other pyelonephritis strains. The probe for the hemolysin gene hybridized with DNA from all other hemolytic strains. These data indicate that most cases of pyelonephritis are due to a small number of pathogenic clones that express critical determinants of virulence, and that the nucleotide sequences for hemolysin and the Gal--Gal binding adhesin in heterologous strains share homology. We are tempted to speculate that the gene products of these shared regions of the genome might form the basis for a vaccine against pyelonephritis.

  2. Functional Heterogeneity of the UpaH Autotransporter Protein from Uropathogenic Escherichia coli

    PubMed Central

    Allsopp, Luke P.; Beloin, Christophe; Moriel, Danilo Gomes; Totsika, Makrina; Ghigo, Jean-Marc

    2012-01-01

    Uropathogenic Escherichia coli (UPEC) is responsible for the majority of urinary tract infections (UTI). To cause a UTI, UPEC must adhere to the epithelial cells of the urinary tract and overcome the shear flow forces of urine. This function is mediated primarily by fimbrial adhesins, which mediate specific attachment to host cell receptors. Another group of adhesins that contributes to UPEC-mediated UTI is autotransporter (AT) proteins. AT proteins possess a range of virulence properties, such as adherence, aggregation, invasion, and biofilm formation. One recently characterized AT protein of UPEC is UpaH, a large adhesin-involved-in-diffuse-adherence (AIDA-I)-type AT protein that contributes to biofilm formation and bladder colonization. In this study we characterized a series of naturally occurring variants of UpaH. We demonstrate that extensive sequence variation exists within the passenger-encoding domain of UpaH variants from different UPEC strains. This sequence variation is associated with functional heterogeneity with respect to the ability of UpaH to mediate biofilm formation. In contrast, all of the UpaH variants examined retained a conserved ability to mediate binding to extracellular matrix (ECM) proteins. Bioinformatic analysis of the UpaH passenger domain identified a conserved region (UpaHCR) and a hydrophobic region (UpaHHR). Deletion of these domains reduced biofilm formation but not the binding to ECM proteins. Despite variation in the upaH sequence, the transcription of upaH was repressed by a conserved mechanism involving the global regulator H-NS, and mutation of the hns gene relieved this repression. Overall, our findings shed new light on the regulation and functions of the UpaH AT protein. PMID:22904291

  3. Pilicide ec240 Disrupts Virulence Circuits in Uropathogenic Escherichia coli

    PubMed Central

    Greene, Sarah E.; Pinkner, Jerome S.; Chorell, Erik; Dodson, Karen W.; Shaffer, Carrie L.; Conover, Matt S.; Livny, Jonathan; Hadjifrangiskou, Maria; Almqvist, Fredrik

    2014-01-01

    ABSTRACT Chaperone-usher pathway (CUP) pili are extracellular organelles produced by Gram-negative bacteria that mediate bacterial pathogenesis. Small-molecule inhibitors of CUP pili, termed pilicides, were rationally designed and shown to inhibit type 1 or P piliation. Here, we show that pilicide ec240 decreased the levels of type 1, P, and S piliation. Transcriptomic and proteomic analyses using the cystitis isolate UTI89 revealed that ec240 dysregulated CUP pili and decreased motility. Paradoxically, the transcript levels of P and S pilus genes were increased during growth in ec240, even though the level of P and S piliation decreased. In contrast, the most downregulated transcripts after growth in ec240 were from the type 1 pilus genes. Type 1 pilus expression is controlled by inversion of the fimS promoter element, which can oscillate between phase on and phase off orientations. ec240 induced the fimS phase off orientation, and this effect was necessary for the majority of ec240’s inhibition of type 1 piliation. ec240 increased levels of the transcriptional regulators SfaB and PapB, which were shown to induce the fimS promoter phase off orientation. Furthermore, the effect of ec240 on motility was abolished in the absence of the SfaB, PapB, SfaX, and PapX regulators. In contrast to the effects of ec240, deletion of the type 1 pilus operon led to increased S and P piliation and motility. Thus, ec240 dysregulated several uropathogenic Escherichia coli (UPEC) virulence factors through different mechanisms and independent of its effects on type 1 pilus biogenesis and may have potential as an antivirulence compound. PMID:25352623

  4. Uropathogenic Escherichia coli Releases Extracellular Vesicles That Are Associated with RNA

    PubMed Central

    Blenkiron, Cherie; Simonov, Denis; Muthukaruppan, Anita; Tsai, Peter; Dauros, Priscila; Green, Sasha; Hong, Jiwon; Print, Cristin G.

    2016-01-01

    Background Bacterium-to-host signalling during infection is a complex process involving proteins, lipids and other diffusible signals that manipulate host cell biology for pathogen survival. Bacteria also release membrane vesicles (MV) that can carry a cargo of effector molecules directly into host cells. Supported by recent publications, we hypothesised that these MVs also associate with RNA, which may be directly involved in the modulation of the host response to infection. Methods and Results Using the uropathogenic Escherichia coli (UPEC) strain 536, we have isolated MVs and found they carry a range of RNA species. Density gradient centrifugation further fractionated and characterised the MV preparation and confirmed that the isolated RNA was associated with the highest particle and protein containing fractions. Using a new approach, RNA-sequencing of libraries derived from three different ‘size’ RNA populations (<50nt, 50-200nt and 200nt+) isolated from MVs has enabled us to now report the first example of a complete bacterial MV-RNA profile. These data show that MVs carry rRNA, tRNAs, other small RNAs as well as full-length protein coding mRNAs. Confocal microscopy visualised the delivery of lipid labelled MVs into cultured bladder epithelial cells and showed their RNA cargo labelled with 5-EU (5-ethynyl uridine), was transported into the host cell cytoplasm and nucleus. MV RNA uptake by the cells was confirmed by droplet digital RT-PCR of csrC. It was estimated that 1% of MV RNA cargo is delivered into cultured cells. Conclusions These data add to the growing evidence of pathogenic bacterial MV being associated a wide range of RNAs. It further raises the plausibility for MV-RNA-mediated cross-kingdom communication whereby they influence host cell function during the infection process. PMID:27500956

  5. Characterization of a Dipartite Iron Uptake System from Uropathogenic Escherichia coli Strain F11*

    PubMed Central

    Koch, Doreen; Chan, Anson C. K.; Murphy, Michael E. P.; Lilie, Hauke; Grass, Gregor; Nies, Dietrich H.

    2011-01-01

    In the uropathogenic Escherichia coli strain F11, in silico genome analysis revealed the dicistronic iron uptake operon fetMP, which is under iron-regulated control mediated by the Fur regulator. The expression of fetMP in a mutant strain lacking known iron uptake systems improved growth under iron depletion and increased cellular iron accumulation. FetM is a member of the iron/lead transporter superfamily and is essential for iron uptake by the Fet system. FetP is a periplasmic protein that enhanced iron uptake by FetM. Recombinant FetP bound Cu(II) and the iron analog Mn(II) at distinct sites. The crystal structure of the FetP dimer reveals a copper site in each FetP subunit that adopts two conformations: CuA with a tetrahedral geometry composed of His44, Met90, His97, and His127, and CuB, a second degenerate octahedral geometry with the addition of Glu46. The copper ions of each site occupy distinct positions and are separated by ∼1.3 Å. Nearby, a putative additional Cu(I) binding site is proposed as an electron source that may function with CuA/CuB displacement to reduce Fe(III) for transport by FetM. Together, these data indicate that FetMP is an additional iron uptake system composed of a putative iron permease and an iron-scavenging and potentially iron-reducing periplasmic protein. PMID:21596746

  6. Sat, the Secreted Autotransporter Toxin of Uropathogenic Escherichia coli, Is a Vacuolating Cytotoxin for Bladder and Kidney Epithelial Cells

    PubMed Central

    Guyer, Debra M.; Radulovic, Suzana; Jones, Faye-Ellen; Mobley, Harry L. T.

    2002-01-01

    The secreted autotransporter toxin (Sat) of uropathogenic Escherichia coli exhibits cytopathic activity upon incubation with HEp-2 cells. We further investigated the effects of Sat on cell lines more relevant to the urinary tract, namely, those derived from bladder and kidney epithelium. Sat elicited elongation of cells and apparent loosening of cellular junctions upon incubation with Vero kidney cells. Additionally, incubation with Sat triggered significant vacuolation within the cytoplasm of both human bladder (CRL-1749) and kidney (CRL-1573) cell lines. This activity has been associated with only a few other known toxins. Following transurethral infection of CBA mice with a sat mutant, no reduction of CFU in urine, bladder, or kidney tissue was seen compared to that in mice infected with wild-type E. coli CFT073. However, significant histological changes were observed within the kidneys of mice infected with wild-type E. coli CFT073, including dissolution of the glomerular membrane and vacuolation of proximal tubule cells. Such damage was not observed in kidney sections of mice infected with a Sat-deficient mutant. These results indicate that Sat, a vacuolating cytotoxin expressed by uropathogenic E. coli CFT073, elicits defined damage to kidney epithelium during upper urinary tract infection and thus contributes to pathogenesis of urinary tract infection. PMID:12117966

  7. Sat, the secreted autotransporter toxin of uropathogenic Escherichia coli, is a vacuolating cytotoxin for bladder and kidney epithelial cells.

    PubMed

    Guyer, Debra M; Radulovic, Suzana; Jones, Faye-Ellen; Mobley, Harry L T

    2002-08-01

    The secreted autotransporter toxin (Sat) of uropathogenic Escherichia coli exhibits cytopathic activity upon incubation with HEp-2 cells. We further investigated the effects of Sat on cell lines more relevant to the urinary tract, namely, those derived from bladder and kidney epithelium. Sat elicited elongation of cells and apparent loosening of cellular junctions upon incubation with Vero kidney cells. Additionally, incubation with Sat triggered significant vacuolation within the cytoplasm of both human bladder (CRL-1749) and kidney (CRL-1573) cell lines. This activity has been associated with only a few other known toxins. Following transurethral infection of CBA mice with a sat mutant, no reduction of CFU in urine, bladder, or kidney tissue was seen compared to that in mice infected with wild-type E. coli CFT073. However, significant histological changes were observed within the kidneys of mice infected with wild-type E. coli CFT073, including dissolution of the glomerular membrane and vacuolation of proximal tubule cells. Such damage was not observed in kidney sections of mice infected with a Sat-deficient mutant. These results indicate that Sat, a vacuolating cytotoxin expressed by uropathogenic E. coli CFT073, elicits defined damage to kidney epithelium during upper urinary tract infection and thus contributes to pathogenesis of urinary tract infection.

  8. [The comparison of antibiotic susceptibilities of uropathogenic Escherichia coli isolates in transition from CLSI to EUCAST].

    PubMed

    Süzük, Serap; Kaşkatepe, Banu; Avcıküçük, Havva; Aksaray, Sebahat; Başustaoğlu, Ahmet

    2015-10-01

    Determination of treatment protocols for infections according to antimicrobial susceptibility test (AST) results is are important for controlling the problem of antibiotic resistance. Two standards are widely used in the world. One of them is Clinical Laboratory Standards Institute (CLSI) standards used in Turkey for many years and the other is the European Committee on Antimicrobial Susceptibility Testing (EUCAST) standards which is used in European Union member countries and came into use in 2015 in Turkey. Since the EUCAST standards had higher clinical sensitivity limits particularly for gram-negative bacilli compared to CLSI (2009) standards, there will be some changes in antibiotic resistance profiles of Turkey with the use of EUCAST. CLSI has changed zone diameters after 2009 versions and the differences between the two standards were brought to a minimum level. Knowledge of local epidemiological data is important to determine empirical therapy which will be used in urinary tract infections (UTI). The aim of this study was to determine the differences of antibiotic susceptibility zone diameters based on our local epidemiological data among uropathogenic Escherichia coli isolates according to EUCAST 2014 and CLSI 2014 standards. A total of 298 E.coli strains isolated from urine samples as the cause of uncomplicated acute UTI agents, were included in the study. Isolates were identified by conventional methods and with BBL Crystal E/NF ID System (Becton Dickinson, USA). AST was performed with Kirby Bauer disk diffusion method and results were evaluated and interpreted according to the CLSI 2014 and EUCAST 2014 standards. According to the results, susceptibility rates of isolates against amikacin (100%) and trimethoprim-sulfamethoxazole (63.09%) were identical in both standards. However, statistically significant differences were observed between CLSI and EUCAST standards in terms of susceptibilities against gentamicin (91.95% and 84.56%, respectively; p= 0

  9. Epigenetic Influence of Dam Methylation on Gene Expression and Attachment in Uropathogenic Escherichia coli.

    PubMed

    Stephenson, Stacy Ann-Marie; Brown, Paul D

    2016-01-01

    Urinary tract infections (UTI) are among the most frequently encountered infections in clinical practice globally. Predominantly a burden among female adults and infants, UTIs primarily caused by uropathogenic Escherichia coli (UPEC) results in high morbidity and fiscal health strains. During pathogenesis, colonization of the urinary tract via fimbrial adhesion to mucosal cells is the most critical point in infection and has been linked to DNA methylation. Furthermore, with continuous exposure to antibiotics as the standard therapeutic strategy, UPEC has evolved to become highly adaptable in circumventing the effect of antimicrobial agents and host defenses. Hence, the need for alternative treatment strategies arises. Since differential DNA methylation is observed as a critical precursor to virulence in various pathogenic bacteria, this body of work sought to assess the influence of the DNA adenine methylase (dam) gene on gene expression and cellular adhesion in UPEC and its potential as a therapeutic target. To monitor the influence of dam on attachment and FQ resistance, selected UPEC dam mutants created via one-step allelic exchange were transformed with cloned qnrA and dam complement plasmid for comparative analysis of growth rate, antimicrobial susceptibility, biofilm formation, gene expression, and mammalian cell attachment. The absence of DNA methylation among dam mutants was apparent. Varying deficiencies in cell growth, antimicrobial resistance and biofilm formation, alongside low-level increases in gene expression (recA and papI), and adherence to HEK-293 and HTB-9 mammalian cells were also detected as a factor of SOS induction to result in increased mutability. Phenotypic characteristics of parental strains were restored in dam complement strains. Dam's vital role in DNA methylation and gene expression in local UPEC isolates was confirmed. Similarly to dam-deficient Enterohemorrhagic E. coli (EHEC), these findings suggest unsuccessful therapeutic use of

  10. Epigenetic Influence of Dam Methylation on Gene Expression and Attachment in Uropathogenic Escherichia coli

    PubMed Central

    Stephenson, Stacy Ann-Marie; Brown, Paul D.

    2016-01-01

    Urinary tract infections (UTI) are among the most frequently encountered infections in clinical practice globally. Predominantly a burden among female adults and infants, UTIs primarily caused by uropathogenic Escherichia coli (UPEC) results in high morbidity and fiscal health strains. During pathogenesis, colonization of the urinary tract via fimbrial adhesion to mucosal cells is the most critical point in infection and has been linked to DNA methylation. Furthermore, with continuous exposure to antibiotics as the standard therapeutic strategy, UPEC has evolved to become highly adaptable in circumventing the effect of antimicrobial agents and host defenses. Hence, the need for alternative treatment strategies arises. Since differential DNA methylation is observed as a critical precursor to virulence in various pathogenic bacteria, this body of work sought to assess the influence of the DNA adenine methylase (dam) gene on gene expression and cellular adhesion in UPEC and its potential as a therapeutic target. To monitor the influence of dam on attachment and FQ resistance, selected UPEC dam mutants created via one-step allelic exchange were transformed with cloned qnrA and dam complement plasmid for comparative analysis of growth rate, antimicrobial susceptibility, biofilm formation, gene expression, and mammalian cell attachment. The absence of DNA methylation among dam mutants was apparent. Varying deficiencies in cell growth, antimicrobial resistance and biofilm formation, alongside low-level increases in gene expression (recA and papI), and adherence to HEK-293 and HTB-9 mammalian cells were also detected as a factor of SOS induction to result in increased mutability. Phenotypic characteristics of parental strains were restored in dam complement strains. Dam’s vital role in DNA methylation and gene expression in local UPEC isolates was confirmed. Similarly to dam-deficient Enterohemorrhagic E. coli (EHEC), these findings suggest unsuccessful therapeutic use

  11. Pathotypic and Phylogenetic Study of Diarrheagenic Escherichia coli and Uropathogenic E. coli Using Multiplex Polymerase Chain Reaction

    PubMed Central

    Salmani, Hamzeh; Azarnezhad, Asaad; Fayazi, Mohammad Reza; Hosseini, Arshad

    2016-01-01

    Background: Acute diarrheal disease and urinary tract infection are leading causes of childhood morbidity and mortality in the developing world. Diarrheagenic Escherichia coli (DEC) has been identified as a major etiologic agent of diarrhea worldwide, and urinary tract infection (UTI) caused by uropathogenic Escherichia coli (UPEC) is one of the most common bacterial infections among human beings. Quick and precise detection of these bacteria help provide more effective intervention and management of infection. Objectives: In this study we present a precise and sensitive typing and phylogenetic study of UPEC and DEC using multiplex PCR in order to simplify and improve the intervention and management of diarrheal and UT infections. Materials and Methods: In total, 100 urinary tract infection samples (UTI) and 200 specimens from children with diarrhea, which had been diagnosed with E. coli as the underlying agent by differential diagnosis using MacConkey’s agar and biochemical study, were submitted for molecular detection. Pathotyping of E. coli pathotypes causing urinary tract infection and diarrhea were examined using a two set multiplex PCR, targeting six specific genes. Phylogenetic typing was done by targeting three genes, including ChuA, YjaA and TspE4C2. Results: Overall, 88% of DEC and 54% of UTI isolates were positive for one or more of the six genes encoding virulence factors. Prevalence of the genes encoding virulence factors for DEC were 62%, 25%, 24%, 13%, 7% and 5% for ST (ETEC), LT (ETEC), aggR (EAggEC), daaD (DAEC), invE (EIEC) and eae (EPEC), respectively; whereas, the prevalence rates for the UTI samples were 23%, 14%, 6%, 6% and 4% for aggR (EAggEC), LT (ETEC), daaD (DAEC), invE (EIEC) and ST (ETEC), respectively. No coding virulence factors were detected for eae (EPEC). Group B2 was the most prevalent phylogroup and ST was the most frequently detected pathotype in all phylogroups. Conclusions: ETEC and EAggEC were the most detected E. coli among

  12. Mechanisms of antibiotic resistance to enrofloxacin in uropathogenic Escherichia coli in dog

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Escherichia coli (E. coli) urinary tract infections (UTIs) are becoming a serious problem both for pets and humans (zoonosis) due to the close contact and to the increasing resistance to antibiotics. Canine E. coli represents a good experimental model useful to study this pathology. Moreover, as des...

  13. Antibiotic Resistance, Virulence, and Genetic Background of Community-Acquired Uropathogenic Escherichia coli from Algeria.

    PubMed

    Yahiaoui, Merzouk; Robin, Frédéric; Bakour, Rabah; Hamidi, Moufida; Bonnet, Richard; Messai, Yamina

    2015-10-01

    The aim of the study was to investigate antibiotic resistance mechanisms, virulence traits, and genetic background of 150 nonrepetitive community-acquired uropathogenic Escherichia coli (CA-UPEC) from Algeria. A rate of 46.7% of isolates was multidrug resistant. bla genes detected were blaTEM (96.8% of amoxicillin-resistant isolates), blaCTX-M-15 (4%), overexpressed blaAmpC (4%), blaSHV-2a, blaTEM-4, blaTEM-31, and blaTEM-35 (0.7%). All tetracycline-resistant isolates (51.3%) had tetA and/or tetB genes. Sulfonamides and trimethoprim resistance genes were sul2 (60.8%), sul1 (45.9%), sul3 (6.7%), dfrA14 (25.4%), dfrA1 (18.2%), dfrA12 (16.3%), and dfrA25 (5.4%). High-level fluoroquinolone resistance (22.7%) was mediated by mutations in gyrA (S83L-D87N) and parC (S80I-E84G/V or S80I) genes. qnrB5, qnrS1, and aac(6')-Ib-cr were rare (5.3%). Class 1 and/or class 2 integrons were detected (40.7%). Isolates belonged to phylogroups B2+D (50%), A+B1 (36%), and F+C+Clade I (13%). Most of D (72.2%) and 38.6% of B2 isolates were multidrug resistant; they belong to 14 different sequence types, including international successful ST131, ST73, and ST69, reported for the first time in the community in Algeria and new ST4494 and ST4529 described in this study. Besides multidrug resistance, B2 and D isolates possessed virulence factors of colonization, invasion, and long-term persistence. The study highlighted multidrug-resistant CA-UPEC with high virulence traits and an epidemic genetic background.

  14. Inactivation of uropathogenic Escherichia coli in ground chicken meat using high pressure processing and gamma radiation, and in purge and chicken meat surfaces by ultraviolet light

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Uropathogenic Escherichia coli (UPEC) are common contaminants in meat and poultry. Nonthermal food safety intervention technologies used to improve safety and shelf-life of both human and pet foods can include high pressure processing (HPP), ionizing (gamma) radiation (GR), and ultraviolet light (UV...

  15. Type II secretory pathway for surface secretion of DraD invasin from the uropathogenic Escherichia coli Dr+ strain.

    PubMed

    Zalewska-Piatek, Beata; Bury, Katarzyna; Piatek, Rafal; Bruzdziak, Piotr; Kur, Józef

    2008-07-01

    The virulence of the uropathogenic Escherichia coli Dr(+) IH11128 strain is associated with the presence of Dr fimbrial structures and a DraD invasin which can act as a fimbrial capping domain at the bacterial cell surface. However, a recent study suggests that the DraD protein is surface exposed in two forms: fimbria associated and fimbria nonassociated (prone to interaction with the N-terminal extension of the DraE protein located on the fimbrial tip). The actual mechanism of DraD surface secretion is presently unknown. We identified a previously unrecognized type II secretory pathway (secreton) in the uropathogenic E. coli Dr(+) strain which is well conserved among gram-negative bacteria and used mainly for secretion of virulence determinants. An active secreton is composed of 12 to 15 different proteins, among which GspD functions as an outer-membrane channel to permit extrusion of proteins in a folded state. Therefore, we inactivated the pathway by inserting the group II intron into a gspD gene of the type II secretion machinery by site-specific recombination. DraD secretion by the E. coli Dr(+) and gspD mutant strains was determined by immunofluorescence microscopy (with antibodies raised against DraD) and an assay of cell binding between bacteria and HeLa cells. The specificity of DraD-mediated bacterial binding for the integrin receptor was confirmed by examination of the adhesion of DraD-coated beads to HeLa cells in the presence and absence of alpha(5)beta(1) monoclonal antibodies. The investigations that we performed showed that type II secretion in E. coli Dr(+) strains leads to DraD translocation at the bacterial cell surfaces.

  16. Human Bladder Uroepithelial Cells Synergize with Monocytes to Promote IL-10 Synthesis and Other Cytokine Responses to Uropathogenic Escherichia coli

    PubMed Central

    Duell, Benjamin L.; Carey, Alison J.; Dando, Samantha J.; Schembri, Mark A.; Ulett, Glen C.

    2013-01-01

    Urinary tract infections are a major source of morbidity for women and the elderly, with Uropathogenic Escherichia coli (UPEC) being the most prevalent causative pathogen. Studies in recent years have defined a key anti-inflammatory role for Interleukin-10 (IL-10) in urinary tract infection mediated by UPEC and other uropathogens. We investigated the nature of the IL-10-producing interactions between UPEC and host cells by utilising a novel co-culture model that incorporated lymphocytes, mononuclear and uroepithelial cells in histotypic proportions. This co-culture model demonstrated synergistic IL-10 production effects between monocytes and uroepithelial cells following infection with UPEC. Membrane inserts were used to separate the monocyte and uroepithelial cell types during infection and revealed two synergistic IL-10 production effects based on contact-dependent and soluble interactions. Analysis of a comprehensive set of immunologically relevant biomarkers in monocyte-uroepithelial cell co-cultures highlighted that multiple cytokine, chemokine and signalling factors were also produced in a synergistic or antagonistic fashion. These results demonstrate that IL-10 responses to UPEC occur via multiple interactions between several cells types, implying a complex role for infection-related IL-10 during UTI. Development and application of the co-culture model described in this study is thus useful to define the degree of contact dependency of biomarker production to UPEC, and highlights the relevance of histotypic co-cultures in studying complex host-pathogen interactions. PMID:24155979

  17. Human bladder uroepithelial cells synergize with monocytes to promote IL-10 synthesis and other cytokine responses to uropathogenic Escherichia coli.

    PubMed

    Duell, Benjamin L; Carey, Alison J; Dando, Samantha J; Schembri, Mark A; Ulett, Glen C

    2013-01-01

    Urinary tract infections are a major source of morbidity for women and the elderly, with Uropathogenic Escherichia coli (UPEC) being the most prevalent causative pathogen. Studies in recent years have defined a key anti-inflammatory role for Interleukin-10 (IL-10) in urinary tract infection mediated by UPEC and other uropathogens. We investigated the nature of the IL-10-producing interactions between UPEC and host cells by utilising a novel co-culture model that incorporated lymphocytes, mononuclear and uroepithelial cells in histotypic proportions. This co-culture model demonstrated synergistic IL-10 production effects between monocytes and uroepithelial cells following infection with UPEC. Membrane inserts were used to separate the monocyte and uroepithelial cell types during infection and revealed two synergistic IL-10 production effects based on contact-dependent and soluble interactions. Analysis of a comprehensive set of immunologically relevant biomarkers in monocyte-uroepithelial cell co-cultures highlighted that multiple cytokine, chemokine and signalling factors were also produced in a synergistic or antagonistic fashion. These results demonstrate that IL-10 responses to UPEC occur via multiple interactions between several cells types, implying a complex role for infection-related IL-10 during UTI. Development and application of the co-culture model described in this study is thus useful to define the degree of contact dependency of biomarker production to UPEC, and highlights the relevance of histotypic co-cultures in studying complex host-pathogen interactions.

  18. The Escherichia coli uropathogenic-specific-protein-associated immunity protein 3 (Imu3) has nucleic acid -binding activity

    PubMed Central

    2014-01-01

    Background The Escherichia coli uropathogenic-specific protein (Usp) is a bacteriocin-like genotoxin, active against mammalian cells and associated with E. coli strains that provoke pyelonephritis, prostatitis and bacteraemia. Usp is encoded by a small pathogenicity island with three downstream small open reading frames (Imu1-3) that are believed to provide immunity to the producer. To prevent host suicide, colicins, bacteriocins of E. coli, form tight complexes with their cognate immunity proteins. Colicin – immunity protein complexes are among the strongest protein complexes known. Here, the Usp associated immunity protein 3 (Imu3) was partially characterized to gain insight into its role and mechanism of activity. Results Isolation and partial characterisation of the Usp-associated immunity protein-3 (Imu3) revealed that, while Usp and Imu3 do not form a high affinity complex, Imu3 exhibits DNA and RNA binding activity. Imu3 was also shown to protect DNA against degradation by colicin E7. Conclusions Our data infer that nonspecific DNA binding of the Imu3 immunity protein, prevents suicide of E. coli producing the genotoxin Usp. PMID:24472116

  19. OCCURRENCE OF ANTIBIOTIC-RESISTANT UROPATHOGENIC ESCHERICHIA COLI CLONAL GROUP A IN WASTEWATER EFFLUENTS

    EPA Science Inventory

    Isolates of Escherichia coli belonging to clonal group A (CGA), a recently described disseminated cause of drug-resistant urinary tract infections in humans, were present in four of seven sewage effluents collected from geographically dispersed areas of the United States. ...

  20. Uropathogenic Escherichia coli Metabolite-Dependent Quiescence and Persistence May Explain Antibiotic Tolerance during Urinary Tract Infection

    PubMed Central

    Leatham-Jensen, Mary P.; Mokszycki, Matthew E.; Rowley, David C.; Deering, Robert; Camberg, Jodi L.; Sokurenko, Evgeni V.; Tchesnokova, Veronika L.; Frimodt-Møller, Jakob; Leth Nielsen, Karen; Sun, Gongqin

    2016-01-01

    ABSTRACT In the present study, it is shown that although Escherichia coli CFT073, a human uropathogenic (UPEC) strain, grows in liquid glucose M9 minimal medium, it fails to grow on glucose M9 minimal medium agar plates seeded with ≤106 CFU. The cells on glucose plates appear to be in a “quiescent” state that can be prevented by various combinations of lysine, methionine, and tyrosine. Moreover, the quiescent state is characteristic of ~80% of E. coli phylogenetic group B2 multilocus sequence type 73 strains, as well as 22.5% of randomly selected UPEC strains isolated from community-acquired urinary tract infections in Denmark. In addition, E. coli CFT073 quiescence is not limited to glucose but occurs on agar plates containing a number of other sugars and acetate as sole carbon sources. It is also shown that a number of E. coli CFT073 mini-Tn5 metabolic mutants (gnd, gdhA, pykF, sdhA, and zwf) are nonquiescent on glucose M9 minimal agar plates and that quiescence requires a complete oxidative tricarboxylic acid (TCA) cycle. In addition, evidence is presented that, although E. coli CFT073 quiescence and persistence in the presence of ampicillin are alike in that both require a complete oxidative TCA cycle and each can be prevented by amino acids, E. coli CFT073 quiescence occurs in the presence or absence of a functional rpoS gene, whereas maximal persistence requires a nonfunctional rpoS. Our results suggest that interventions targeting specific central metabolic pathways may mitigate UPEC infections by interfering with quiescence and persistence. IMPORTANCE Recurrent urinary tract infections (UTIs) affect 10 to 40% of women. In up to 77% of those cases, the recurrent infections are caused by the same uropathogenic E. coli (UPEC) strain that caused the initial infection. Upon infection of urothelial transitional cells in the bladder, UPEC appear to enter a nongrowing quiescent intracellular state that is thought to serve as a reservoir responsible

  1. Uropathogenic Escherichia coli Metabolite-Dependent Quiescence and Persistence May Explain Antibiotic Tolerance during Urinary Tract Infection.

    PubMed

    Leatham-Jensen, Mary P; Mokszycki, Matthew E; Rowley, David C; Deering, Robert; Camberg, Jodi L; Sokurenko, Evgeni V; Tchesnokova, Veronika L; Frimodt-Møller, Jakob; Krogfelt, Karen A; Leth Nielsen, Karen; Frimodt-Møller, Niels; Sun, Gongqin; Cohen, Paul S

    2016-01-01

    In the present study, it is shown that although Escherichia coli CFT073, a human uropathogenic (UPEC) strain, grows in liquid glucose M9 minimal medium, it fails to grow on glucose M9 minimal medium agar plates seeded with ≤10(6) CFU. The cells on glucose plates appear to be in a "quiescent" state that can be prevented by various combinations of lysine, methionine, and tyrosine. Moreover, the quiescent state is characteristic of ~80% of E. coli phylogenetic group B2 multilocus sequence type 73 strains, as well as 22.5% of randomly selected UPEC strains isolated from community-acquired urinary tract infections in Denmark. In addition, E. coli CFT073 quiescence is not limited to glucose but occurs on agar plates containing a number of other sugars and acetate as sole carbon sources. It is also shown that a number of E. coli CFT073 mini-Tn5 metabolic mutants (gnd, gdhA, pykF, sdhA, and zwf) are nonquiescent on glucose M9 minimal agar plates and that quiescence requires a complete oxidative tricarboxylic acid (TCA) cycle. In addition, evidence is presented that, although E. coli CFT073 quiescence and persistence in the presence of ampicillin are alike in that both require a complete oxidative TCA cycle and each can be prevented by amino acids, E. coli CFT073 quiescence occurs in the presence or absence of a functional rpoS gene, whereas maximal persistence requires a nonfunctional rpoS. Our results suggest that interventions targeting specific central metabolic pathways may mitigate UPEC infections by interfering with quiescence and persistence. IMPORTANCE Recurrent urinary tract infections (UTIs) affect 10 to 40% of women. In up to 77% of those cases, the recurrent infections are caused by the same uropathogenic E. coli (UPEC) strain that caused the initial infection. Upon infection of urothelial transitional cells in the bladder, UPEC appear to enter a nongrowing quiescent intracellular state that is thought to serve as a reservoir responsible for recurrent

  2. Temperature control of molecular circuit switch responsible for virulent phenotype expression in uropathogenic Escherichia coli

    NASA Astrophysics Data System (ADS)

    Samoilov, Michael

    2010-03-01

    The behavior and fate of biological organisms are to a large extent dictated by their environment, which can be often viewed as a collection of features and constraints governed by physics laws. Since biological systems comprise networks of molecular interactions, one such key physical property is temperature, whose variations directly affect the rates of biochemical reactions involved. For instance, temperature is known to control many gene regulatory circuits responsible for pathogenicity in bacteria. One such example is type 1 fimbriae (T1F) -- the foremost virulence factor in uropathogenic E. coli (UPEC), which accounts for 80-90% of all community-acquired urinary tract infections (UTIs). The expression of T1F is randomly `phase variable', i.e. individual cells switch between virulent/fimbriate and avirulent/afimbriate phenotypes, with rates regulated by temperature. Our computational investigation of this process, which is based on FimB/FimE recombinase-mediated inversion of fimS DNA element, offers new insights into its discrete-stochastic kinetics. In particular, it elucidates the logic of T1F control optimization to the host temperature and contributes further understanding toward the development of novel therapeutic approaches to UPEC-caused UTIs.

  3. Population structure and uropathogenic virulence-associated genes of faecal Escherichia coli from healthy young and elderly adults.

    PubMed

    Vollmerhausen, Tara L; Ramos, Nubia L; Gündogdu, Aycan; Robinson, Wayne; Brauner, Annelie; Katouli, Mohammad

    2011-05-01

    We investigated the population structures of faecal Escherichia coli in 30 healthy young adults (13 males and 17 females) aged between 20 and 45 years and 29 elderly adults (14 females and 15 males) aged between 65 and 77 years. In all, 1566 strains were typed with the PhPlate system and grouped into biochemical phenotypes (BPTs). Strains with shared BPTs were further typed using randomly amplified polymorphic DNA analysis. Forty-four per cent of the strains were shared between two or more age and gender groups. Elders had a significantly higher (P<0.001) number of BPTs (mean±standard error 3.3±0.27) than younger groups (1.82±0.27). Phylogenetic affiliation and virulence-associated genes (VAGs) of the strains showed that more than 80 % of the strains belonging to dominant types belonged to phylogroups B2 and D. Amongst dominant BPTs, phylogenetic group A was significantly associated with females (P<0.0001), and elders were more likely to carry group D (P<0.0124). Elderly males had a higher prevalence of VAGs than young males (P<0.0001) and young females (P<0.0005). We conclude that there is a lower prevalence of E. coli with uropathogenic properties in healthy young adults than in elders. PMID:21292854

  4. Mechanisms of antibiotic resistance to enrofloxacin in uropathogenic Escherichia coli in dog.

    PubMed

    Piras, Cristian; Soggiu, Alessio; Greco, Viviana; Martino, Piera Anna; Del Chierico, Federica; Putignani, Lorenza; Urbani, Andrea; Nally, Jarlath E; Bonizzi, Luigi; Roncada, Paola

    2015-09-01

    Escherichia coli (E. coli) urinary tract infections (UTIs) are becoming a serious problem both for pets and humans (zoonosis) due to the close contact and to the increasing resistance to antibiotics. This study has been performed in order to unravel the mechanism of induced enrofloxacin resistance in canine E. coli isolates that represent a good tool to study this pathology. The isolated E. coli has been induced with enrofloxacin and studied through 2D DIGE and shotgun MS. Discovered differentially expressed proteins are principally involved in antibiotic resistance and linked to oxidative stress response, to DNA protection and to membrane permeability. Moreover, since enrofloxacin is an inhibitor of DNA gyrase, the overexpression of DNA starvation/stationary phase protection protein (Dsp) could be a central point to discover the mechanism of this clone to counteract the effects of enrofloxacin. In parallel, the dramatic decrease of the synthesis of the outer membrane protein W, which represents one of the main gates for enrofloxacin entrance, could explain additional mechanism of E. coli defense against this antibiotic. All 2D DIGE and MS data have been deposited into the ProteomeXchange Consortium with identifier PXD002000 and DOI http://dx.doi.org/10.6019/PXD002000. This article is part of a Special Issue entitled: HUPO 2014. PMID:26066767

  5. Siderophore Biosynthesis Governs the Virulence of Uropathogenic Escherichia coli by Coordinately Modulating the Differential Metabolism.

    PubMed

    Su, Qiao; Guan, Tianbing; He, Yan; Lv, Haitao

    2016-04-01

    Urinary tract infections impose substantial health burdens on women worldwide. Urinary tract infections often incur a high risk of recurrence and antibiotic resistance, and uropathogenic E. coli accounts for approximately 80% of clinically acquired cases. The diagnosis of, treatment of, and drug development for urinary tract infections remain substantial challenges due to the complex pathogenesis of this condition. The clinically isolated UPEC 83972 strain was found to produce four siderophores: yersiniabactin, aerobactin, salmochelin, and enterobactin. The biosyntheses of some of these siderophores implies that the virulence of UPEC is mediated via the targeting of primary metabolism. However, the differential modulatory roles of siderophore biosyntheses on the differential metabolomes of UPEC and non-UPEC strains remain incompletely understood. In the present study, we sought to investigate how the differential metabolomes can be used to distinguish UPEC from non-UPEC strains and to determine the associated regulatory roles of siderophore biosynthesis. Our results are the first to demonstrate that the identified differential metabolomes strongly differentiated UPEC from non-UPEC strains. Furthermore, we performed metabolome assays of mutants with different patterns of siderophore deletions; the data revealed that the mutations of all four siderophores exerted a stronger modulatory role on the differential metabolomes of the UPEC and non-UPEC strains relative to the mutation of any single siderophore and that this modulatory role primarily involved amino acid metabolism, oxidative phosphorylation in the carbon fixation pathway, and purine and pyrimidine metabolism. Surprisingly, the modulatory roles were strongly dependent on the type and number of mutated siderophores. Taken together, these results demonstrated that siderophore biosynthesis coordinately modulated the differential metabolomes and thus may indicate novel targets for virulence-based diagnosis

  6. Development of a fluorometric microplate antiadhesion assay using uropathogenic Escherichia coli and human uroepithelial cells.

    PubMed

    Kimble, Lindsey L; Mathison, Bridget D; Kaspar, Kerrie L; Khoo, Christina; Chew, Boon P

    2014-05-23

    A fluorometric microplate assay has been developed to determine Escherichia (E.) coli adhesion to uroepithelial cells (UEC). P-fimbriated E. coli were labeled with BacLight Green and preincubated 30 min with human urine or standard. Fluorescent-E. coli were added to UEC in mircoplates at a 400:1 ratio, incubated 1 h, and washed, and the fluorescence intensity was measured. Specific labeling and adherence were confirmed by flow cytometry. A myricetin (1) standard curve (0-30 μg/mL) was developed; the lower limit of detection was 0.1 μg/mL, and half-maximal inhibitory concentration was 0.88 μg/mL (intra- and interassay coefficients of variance were <10% and <15%, respectively). Vaccinium macrocarpon (cranberry) extracts, quercetin (2), and procyanidins B1 (3), B2 (4), and C1 (5) showed similar inhibition. Antiadhesion activity of urine samples from subjects (n = 12) consuming placebo or V. macrocarpon beverage determined using this assay was positively correlated (R(2) = 0.78; p < 0.01) with a radiolabeled-E. coli assay.

  7. Antibiotic resistance profile and virulence genes of uropathogenic Escherichia coli isolates in relation to phylogeny.

    PubMed

    Adib, N; Ghanbarpour, R; Solatzadeh, H; Alizade, H

    2014-03-01

    Escherichia coli (E. coli) strains are the major cause of urinary tract infections (UTI) and belong to the large group of extra-intestinal pathogenic E. coli. The purposes of this study were to determine the antibiotic resistance profile, virulence genes and phylogenetic background of E. coli isolates from UTI cases. A total of 137 E. coli isolates were obtained from UTI samples. The antimicrobial susceptibility of confirmed isolates was determined by disk diffusion method against eight antibiotics. The isolates were examined to determine the presence and prevalence of selected virulence genes including iucD, sfa/focDE, papEF and hly. ECOR phylo-groups of isolates were determined by detection of yjaA and chuA genes and fragment TspE4.C2. The antibiogram results showed that 71% of the isolates were resistant to cefazolin, 60.42% to co-trimoxazole, 54.16% to nalidixic acid, 36.45% to gentamicin, 29.18% to ciprofloxacin, 14.58% to cefepime, 6.25% to nitrofurantoin and 0.00% to imipenem. Twenty-two antibiotic resistance patterns were observed among the isolates. Virulence genotyping of isolates revealed that 58.39% isolates had at least one of the four virulence genes. The iucD gene was the most prevalent gene (43.06%). The other genes including sfa/focDE, papEF and hly genes were detected in 35.76%, 18.97% and 2.18% isolates, respectively. Nine combination patterns of the virulence genes were detected in isolates. Phylotyping of 137 isolates revealed that the isolates fell into A (45.99%), B1 (13.14%), B2 (19.71%) and D (21.16%) groups. Phylotyping of multidrug resistant isolates indicated that these isolates are mostly in A (60.34%) and D (20.38%) groups. In conclusion, the isolates that possessed the iucD, sfa/focDE, papEF and hly virulence genes mostly belonged to A and B2 groups, whereas antibiotic resistant isolates were in groups A and D. Escherichia coli strains carrying virulence factors and antibiotic resistance are distributed in specific phylogenetic

  8. Molecular Characterization of UpaB and UpaC, Two New Autotransporter Proteins of Uropathogenic Escherichia coli CFT073

    PubMed Central

    Allsopp, Luke P.; Beloin, Christophe; Ulett, Glen C.; Valle, Jaione; Totsika, Makrina; Sherlock, Orla; Ghigo, Jean-Marc

    2012-01-01

    Uropathogenic Escherichia coli (UPEC) is the primary cause of urinary tract infection (UTI) in the developed world. The major factors associated with virulence of UPEC are fimbrial adhesins, which mediate specific attachment to host receptors and trigger innate host responses. Another group of adhesins is represented by the autotransporter (AT) subgroup of proteins. The genome-sequenced prototype UPEC strain CFT073 contains 11 putative AT-encoding genes. In this study, we have performed a detailed molecular characterization of two closely related AT adhesins from CFT073: UpaB (c0426) and UpaC (c0478). PCR screening revealed that the upaB and upaC AT-encoding genes are common in E. coli. The upaB and upaC genes were cloned and characterized in a recombinant E. coli K-12 strain background. This revealed that they encode proteins located at the cell surface but possess different functional properties: UpaB mediates adherence to several ECM proteins, while UpaC expression is associated with increased biofilm formation. In CFT073, upaB is expressed while upaC is transcriptionally repressed by the global regulator H-NS. In competitive colonization experiments employing the mouse UTI model, CFT073 significantly outcompeted its upaB (but not upaC) isogenic mutant strain in the bladder. This attenuated phenotype was also observed in single-challenge experiments, where deletion of the upaB gene in CFT073 significantly reduced early colonization of the bladder. PMID:21930758

  9. A novel two-component signaling system facilitates uropathogenic Escherichia coli's ability to exploit abundant host metabolites.

    PubMed

    Cai, Wentong; Wannemuehler, Yvonne; Dell'anna, Giuseppe; Nicholson, Bryon; Barbieri, Nicolle L; Kariyawasam, Subhashinie; Feng, Yaping; Logue, Catherine M; Nolan, Lisa K; Li, Ganwu

    2013-01-01

    Two-component signaling systems (TCSs) are major mechanisms by which bacteria adapt to environmental conditions. It follows then that TCSs would play important roles in the adaptation of pathogenic bacteria to host environments. However, no pathogen-associated TCS has been identified in uropathogenic Escherichia coli (UPEC). Here, we identified a novel TCS, which we termed KguS/KguR (KguS: α-ketoglutarate utilization sensor; KguR: α-ketoglutarate utilization regulator) in UPEC CFT073, a strain isolated from human pyelonephritis. kguS/kguR was strongly associated with UPEC but was found only rarely among other E. coli including commensal and intestinal pathogenic strains. An in vivo competition assay in a mouse UTI model showed that deletion of kguS/kguR in UPEC CFT073 resulted in a significant reduction in its colonization of the bladders and kidneys of mice, suggesting that KguS/KguR contributed to UPEC fitness in vivo. Comparative proteomics identified the target gene products of KguS/KguR, and sequence analysis showed that TCS KguS/KguR and its targeted-genes, c5032 to c5039, are encoded on a genomic island, which is not present in intestinal pathogenic E. coli. Expression of the target genes was induced by α-ketoglutarate (α-KG). These genes were further shown to be involved in utilization of α-KG as a sole carbon source under anaerobic conditions. KguS/KguR contributed to the regulation of the target genes with the direct regulation by KguR verified using an electrophoretic mobility shift assay. In addition, oxygen deficiency positively modulated expression of kguS/kguR and its target genes. Taken altogether, this study describes the first UPEC-associated TCS that functions in controlling the utilization of α-ketoglutarate in vivo thereby facilitating UPEC adaptation to life inside the urinary tract.

  10. Siderophore biosynthesis coordinately modulated the virulence-associated interactive metabolome of uropathogenic Escherichia coli and human urine

    PubMed Central

    Su, Qiao; Guan, Tianbing; Lv, Haitao

    2016-01-01

    Uropathogenic Escherichia coli (UPEC) growth in women’s bladders during urinary tract infection (UTI) incurs substantial chemical exchange, termed the “interactive metabolome”, which primarily accounts for the metabolic costs (utilized metabolome) and metabolic donations (excreted metabolome) between UPEC and human urine. Here, we attempted to identify the individualized interactive metabolome between UPEC and human urine. We were able to distinguish UPEC from non-UPEC by employing a combination of metabolomics and genetics. Our results revealed that the interactive metabolome between UPEC and human urine was markedly different from that between non-UPEC and human urine, and that UPEC triggered much stronger perturbations in the interactive metabolome in human urine. Furthermore, siderophore biosynthesis coordinately modulated the individualized interactive metabolome, which we found to be a critical component of UPEC virulence. The individualized virulence-associated interactive metabolome contained 31 different metabolites and 17 central metabolic pathways that were annotated to host these different metabolites, including energetic metabolism, amino acid metabolism, and gut microbe metabolism. Changes in the activities of these pathways mechanistically pinpointed the virulent capability of siderophore biosynthesis. Together, our findings provide novel insights into UPEC virulence, and we propose that siderophores are potential targets for further discovery of drugs to treat UPEC-induced UTI. PMID:27076285

  11. Role of P-fimbrial-mediated adherence in pyelonephritis and persistence of uropathogenic Escherichia coli (UPEC) in the mammalian kidney.

    PubMed

    Lane, M C; Mobley, H L T

    2007-07-01

    P fimbria, a mannose-resistant adhesin of uropathogenic Escherichia coli (UPEC), has been shown to be associated with acute pyelonephritis. The pap gene cluster encodes the proteins required for P-fimbrial biogenesis, including papG, which encodes the tip adhesin. The three most studied PapG molecular variants, which are shown to bind distinct isoreceptors, are PapGI, -II, and -III. PapGII preferentially binds globoside, or GbO4, a glycolipid isoreceptor of the human kidney. Studies using different animal models of ascending urinary tract infection (UTI) have demonstrated a variable role for P fimbriae, and specifically PapGII-mediated adherence, in renal colonization. The disparities in the results obtained from those studies are likely to be attributed to the differences in animal models and UPEC strains utilized. One explanation that is discussed in detail is the contribution of multiple fimbriae of UPEC that potentially mediate adherence to the mammalian kidney. Overall, P fimbriae appear to play some role in mediating adherence to uroepithelial cells in vivo and establishing an inflammatory response during renal colonization, thus contributing to kidney damage during acute pyelonephritis. To verify that P fimbriae contribute to the pathogenesis of UPEC during ascending UTI (and in particular acute pyelonephritis), future studies should be conducted to satisfy fully all three tenets of the molecular Koch's postulates, including complementation of a mutated allele.

  12. Siderophore biosynthesis coordinately modulated the virulence-associated interactive metabolome of uropathogenic Escherichia coli and human urine.

    PubMed

    Su, Qiao; Guan, Tianbing; Lv, Haitao

    2016-04-14

    Uropathogenic Escherichia coli (UPEC) growth in women's bladders during urinary tract infection (UTI) incurs substantial chemical exchange, termed the "interactive metabolome", which primarily accounts for the metabolic costs (utilized metabolome) and metabolic donations (excreted metabolome) between UPEC and human urine. Here, we attempted to identify the individualized interactive metabolome between UPEC and human urine. We were able to distinguish UPEC from non-UPEC by employing a combination of metabolomics and genetics. Our results revealed that the interactive metabolome between UPEC and human urine was markedly different from that between non-UPEC and human urine, and that UPEC triggered much stronger perturbations in the interactive metabolome in human urine. Furthermore, siderophore biosynthesis coordinately modulated the individualized interactive metabolome, which we found to be a critical component of UPEC virulence. The individualized virulence-associated interactive metabolome contained 31 different metabolites and 17 central metabolic pathways that were annotated to host these different metabolites, including energetic metabolism, amino acid metabolism, and gut microbe metabolism. Changes in the activities of these pathways mechanistically pinpointed the virulent capability of siderophore biosynthesis. Together, our findings provide novel insights into UPEC virulence, and we propose that siderophores are potential targets for further discovery of drugs to treat UPEC-induced UTI.

  13. Expression of suppressor of cytokine signalling 3 (SOCS3) in human bladder epithelial cells infected with uropathogenic Escherichia coli.

    PubMed

    Demirel, Isak; Säve, Susanne; Kruse, Robert; Persson, Katarina

    2013-02-01

    Suppressor of cytokine signalling (SOCS) proteins inhibit pro-inflammatory signalling mediated by Janus-activated kinase (JAK)-signal transducer and activator of transcription (STAT) pathways. To evade the immune response some pathogens appear to modify the host SOCS proteins. Uropathogenic Escherichia coli (UPEC) are able to subvert the host response evoked by bladder epithelial cells, but the mechanisms are not fully understood. The objective of this study was to investigate whether UPEC can modify the host SOCS and STAT3 response. Real time RT-PCR studies demonstrated an increased SOCS1 and SOCS3 expression in the isolated human bladder epithelial cell lines (RT-4 and 5637) in response to cytokines. UPEC strain IA2 increased SOCS3, but not SOCS1, mRNA levels with a peak at 6 h after infection. The increase of SOCS3 was confirmed at the protein level by Western blotting. The UPEC strain IA2 caused a time-dependent decrease in the phosphorylation of STAT3. This study demonstrates that UPEC are able to affect SOCS3 and STAT3 signalling in human uroepithelial cells. The finding that UPEC are able to induce mediators involved in suppression of host cytokine signalling may help to elucidate how UPEC may circumvent the host response during urinary tract infection.

  14. Immune modulation by group B Streptococcus influences host susceptibility to urinary tract infection by uropathogenic Escherichia coli.

    PubMed

    Kline, Kimberly A; Schwartz, Drew J; Gilbert, Nicole M; Hultgren, Scott J; Lewis, Amanda L

    2012-12-01

    Urinary tract infection (UTI) is most often caused by uropathogenic Escherichia coli (UPEC). UPEC inoculation into the female urinary tract (UT) can occur through physical activities that expose the UT to an inherently polymicrobial periurethral, vaginal, or gastrointestinal flora. We report that a common urogenital inhabitant and opportunistic pathogen, group B Streptococcus (GBS), when present at the time of UPEC exposure, undergoes rapid UPEC-dependent exclusion from the murine urinary tract, yet it influences acute UPEC-host interactions and alters host susceptibility to persistent outcomes of bladder and kidney infection. GBS presence results in increased UPEC titers in the bladder lumen during acute infection and reduced inflammatory responses of murine macrophages to live UPEC or purified lipopolysaccharide (LPS), phenotypes that require GBS mimicry of host sialic acid residues. Taken together, these studies suggest that despite low titers, the presence of GBS at the time of polymicrobial UT exposure may be an overlooked risk factor for chronic pyelonephritis and recurrent UTI in susceptible groups, even if it is outcompeted and thus absent by the time of diagnosis.

  15. Urinary tract infection drives genome instability in uropathogenic Escherichia coli and necessitates translesion synthesis DNA polymerase IV for virulence.

    PubMed

    Gawel, Damian; Seed, Patrick C

    2011-01-01

    Uropathogenic Escherichia coli (UPEC) produces ~80% of community-acquired UTI, the second most common infection in humans. During UTI, UPEC has a complex life cycle, replicating and persisting in intracellular and extracellular niches. Host and environmental stresses may affect the integrity of the UPEC genome and threaten its viability. We determined how the host inflammatory response during UTI drives UPEC genome instability and evaluated the role of multiple factors of genome replication and repair for their roles in the maintenance of genome integrity and thus virulence during UTI. The urinary tract environment enhanced the mutation frequency of UPEC ~100-fold relative to in vitro levels. Abrogation of inflammation through a host TLR4-signaling defect significantly reduced the mutation frequency, demonstrating in the importance of the host response as a driver of UPEC genome instability. Inflammation induces the bacterial SOS response, leading to the hypothesis that the UPEC SOS-inducible translesion synthesis (TLS) DNA polymerases would be key factors in UPEC genome instability during UTI. However, while the TLS DNA polymerases enhanced in vitro, they did not increase in vivo mutagenesis. Although it is not a source of enhanced mutagenesis in vivo, the TLS DNA polymerase IV was critical for the survival of UPEC during UTI during an active inflammatory assault. Overall, this study provides the first evidence of a TLS DNA polymerase being critical for UPEC survival during urinary tract infection and points to independent mechanisms for genome instability and the maintenance of genome replication of UPEC under host inflammatory stress.

  16. The co-transcriptome of uropathogenic Escherichia coli-infected mouse macrophages reveals new insights into host-pathogen interactions.

    PubMed

    Mavromatis, Charalampos Harris; Bokil, Nilesh J; Totsika, Makrina; Kakkanat, Asha; Schaale, Kolja; Cannistraci, Carlo V; Ryu, Taewoo; Beatson, Scott A; Ulett, Glen C; Schembri, Mark A; Sweet, Matthew J; Ravasi, Timothy

    2015-05-01

    Urinary tract infections (UTI) are among the most common infections in humans. Uropathogenic Escherichia coli (UPEC) can invade and replicate within bladder epithelial cells, and some UPEC strains can also survive within macrophages. To understand the UPEC transcriptional programme associated with intramacrophage survival, we performed host-pathogen co-transcriptome analyses using RNA sequencing. Mouse bone marrow-derived macrophages (BMMs) were challenged over a 24 h time course with two UPEC reference strains that possess contrasting intramacrophage phenotypes: UTI89, which survives in BMMs, and 83972, which is killed by BMMs. Neither of these strains caused significant BMM cell death at the low multiplicity of infection that was used in this study. We developed an effective computational framework that simultaneously separated, annotated and quantified the mammalian and bacterial transcriptomes. Bone marrow-derived macrophages responded to the two UPEC strains with a broadly similar gene expression programme. In contrast, the transcriptional responses of the UPEC strains diverged markedly from each other. We identified UTI89 genes up-regulated at 24 h post-infection, and hypothesized that some may contribute to intramacrophage survival. Indeed, we showed that deletion of one such gene (pspA) significantly reduced UTI89 survival within BMMs. Our study provides a technological framework for simultaneously capturing global changes at the transcriptional level in co-cultures, and has generated new insights into the mechanisms that UPEC use to persist within the intramacrophage environment.

  17. Genetic analysis of the gene cluster encoding nonfimbrial adhesin I from an Escherichia coli uropathogen.

    PubMed Central

    Ahrens, R; Ott, M; Ritter, A; Hoschützky, H; Bühler, T; Lottspeich, F; Boulnois, G J; Jann, K; Hacker, J

    1993-01-01

    The chromosomally encoded nonfimbrial adhesion I (NFA-I) from Escherichia coli urinary tract isolate 827 (O83:K1:H4) mediates agglutination of human erythrocytes. Subclones were constructed from an NFA-I-expressing recombinant E. coli K-12 clone, derived from a genomic library of E. coli 827. Minicell analysis and nucleotide sequencing revealed that proteins of 30.5, 9, 80, 15, and 19 kDa encoded on a stretch of approximately 6 kb are involved in the expression of NFA-I. NFA-I exhibits a polymeric structure, which disintegrates with elevated temperature into a 19-kDa monomer but with some relatively stable dimers. By using gold-conjugated monoclonal antibodies directed against NFA-I in electron microscopy, the adhesin could be localized on the outer surface of the recombinant E. coli K-12 bacteria. The nucleotide sequence of the nfaA gene encoding the monomeric structural subunit of the adhesin was determined. An open reading frame of 184 amino acids encoding the NfaA precursor, which is processed to the mature protein, was found; it consisted of 156 amino acids with a calculated molecular weight of 16,000. Peptide sequencing of the NFA-I subunit protein confirmed that this open reading frame corresponds to the NfaA coding locus. Furthermore, the nucleotide sequence of the open reading frame termed NfaE, located at the proximal part of the DNA stretch responsible for NFA-I expression, was elaborated. NfaE consists of 247 amino acids, including a presumptive 29-amino-acid signal peptide, leading to a molecular weight of 24,000 for the mature protein. The nfaE sequence shares homology with the 27-kDa CS3 protein, which is involved in the assembly of CS3 fibrillae, and might encode the 30.5-kDa protein, detected in minicells. Images PMID:8099066

  18. CdiA Effectors from Uropathogenic Escherichia coli Use Heterotrimeric Osmoporins as Receptors to Recognize Target Bacteria

    PubMed Central

    Beck, Christina M.; Willett, Julia L. E.; Kim, Jeff J.; Low, David A.; Hayes, Christopher S.

    2016-01-01

    Many Gram-negative bacterial pathogens express contact-dependent growth inhibition (CDI) systems that promote cell-cell interaction. CDI+ bacteria express surface CdiA effector proteins, which transfer their C-terminal toxin domains into susceptible target cells upon binding to specific receptors. CDI+ cells also produce immunity proteins that neutralize the toxin domains delivered from neighboring siblings. Here, we show that CdiAEC536 from uropathogenic Escherichia coli 536 (EC536) uses OmpC and OmpF as receptors to recognize target bacteria. E. coli mutants lacking either ompF or ompC are resistant to CDIEC536-mediated growth inhibition, and both porins are required for target-cell adhesion to inhibitors that express CdiAEC536. Experiments with single-chain OmpF fusions indicate that the CdiAEC536 receptor is heterotrimeric OmpC-OmpF. Because the OmpC and OmpF porins are under selective pressure from bacteriophages and host immune systems, their surface-exposed loops vary between E. coli isolates. OmpC polymorphism has a significant impact on CDIEC536 mediated competition, with many E. coli isolates expressing alleles that are not recognized by CdiAEC536. Analyses of recombinant OmpC chimeras suggest that extracellular loops L4 and L5 are important recognition epitopes for CdiAEC536. Loops L4 and L5 also account for much of the sequence variability between E. coli OmpC proteins, raising the possibility that CDI contributes to the selective pressure driving OmpC diversification. We find that the most efficient CdiAEC536 receptors are encoded by isolates that carry the same cdi gene cluster as E. coli 536. Thus, it appears that CdiA effectors often bind preferentially to "self" receptors, thereby promoting interactions between sibling cells. As a consequence, these effector proteins cannot recognize nor suppress the growth of many potential competitors. These findings suggest that self-recognition and kin selection are important functions of CDI. PMID:27723824

  19. Molecular epidemiology of adhesin and hemolysin virulence factors among uropathogenic Escherichia coli.

    PubMed

    Arthur, M; Johnson, C E; Rubin, R H; Arbeit, R D; Campanelli, C; Kim, C; Steinbach, S; Agarwal, M; Wilkinson, R; Goldstein, R

    1989-02-01

    The pap, prs, pil, and hly operons of the pyelonephritic Escherichia coli isolate J96 code for the expression of P, F, and type 1 adhesins and the production of hemolysin, respectively; the afaI operon of the pyelonephritic E. coli KS52 encodes an X adhesin. Using different segments of these operons as probes, colony hybridizations were performed on 97 E. coli urinary tract and 40 fecal clinical isolates to determine (i) the presence in the infecting bacteria of nucleotide sequences related to virulence operons, and (ii) the phenotypic properties associated with such sequences. Coexpression of P and F adhesins encoded by pap-related sequences was detected more frequently among isolates from patients with pyelonephritis (32 of 49, 65%) than among those with cystitis (11 of 48, 23%; P less than 0.0001) or from fecal specimens (6 of 40, 15%; P less than 0.0001). Therefore, the expression of both adhesins appears to be critical in the colonization of the upper urinary tract. In contrast, afaI-related sequences were detected significantly more frequently among isolates from patients with cystitis, suggesting that this class of X adhesin may have a role in lower urinary tract infections. Urinary tract isolates differed from fecal isolates by a low incidence of type 1 adhesin expression among pil probe-positive isolates. hly-related sequences were only detected in pap probe-positive isolates. The frequency of hemolysin production among pap probe-positive isolates was not associated with a particular pattern of infection. The distribution of these virulence factors was similar in the presence or absence of reflux, indicating that structural abnormalities of the urinary tract did not facilitate colonization by adhesin-negative isolates.

  20. Characterization of Ciprofloxacin-Resistant and Ciprofloxacin-Susceptible Uropathogenic Escherichia coli Obtained from Patients with Gynecological Cancer.

    PubMed

    Capett, Muniqui S; Vollú-Silva, Patricia; Melchiades, Vanessa A; Bokehi, Luciana C; Araújo, Fernanda M; Martins, Ianick Souto; Neves, Felipe P G; Gonzalez, Alice G M; Oswald, Eric; de Paula, Geraldo R; Teixeira, Lenise A

    2016-11-01

    The objective of this work was to assess the genetic characteristics of uropathogenic Escherichia coli, ciprofloxacin resistance or susceptibility, obtained from patients with gynecological cancer and urinary tract infection (UTI). Seventy-seven E. coli ciprofloxacin-resistant isolates and 38 ciprofloxacin-susceptible were analyzed by polymerase chain reaction (PCR) to determine the phylogenetic groups, virulence factors as iucC, fyuA, hlyC, cnf1 genes, and pks pathogenicity island. The presence of genes related to ciprofloxacin resistance such as qnrA, qnrB, qnrS, aac(6')-Ib-cr, and qepA, and the sequencing of DNA gyrase genes and topoisomerase IV were determined. The genetic profile of the isolates was determined by pulsed-field gel electrophoresis (PFGE). Statistical analysis was performed using Fisher's exact test and Chi-square test. Phylogenetic group B2 was the most prevalent although a great genetic diversity was observed by PFGE. Only genes associated to siderophores were found in ciprofloxacin-resistant isolates; however, in ciprofloxacin-susceptible isolates, genes related to siderophores and toxin, were detected. Additionally qnrB was detected in both populations, ciprofloxacin resistant and susceptible. DNA mutations in gyrA were Ser-83-Leu and Asp-87-Asn and in parC were Ser-80-Ile and Glu-84-Val, Glu-84-Lys. In conclusion, it was observed a high prevalence of qnrB in the population studied; in addition, it was the first time the pks island was observed only in ciprofloxacin-susceptible isolates.

  1. Roles of Putative Type II Secretion and Type IV Pilus Systems in the Virulence of Uropathogenic Escherichia coli

    PubMed Central

    Kulkarni, Ritwij; Dhakal, Bijaya K.; Slechta, E. Susan; Kurtz, Zachary; Mulvey, Matthew A.; Thanassi, David G.

    2009-01-01

    Background Type II secretion systems (T2SS) and the evolutionarily related type IV pili (T4P) are important virulence determinants in many Gram-negative bacterial pathogens. However, the roles of T2SS and T4P in the virulence of extraintestinal pathogenic Escherichia coli have not been determined. Methodology/Principal Findings To investigate the functions of putative T2SS and T4P gene clusters present in the model uropathogenic E. coli (UPEC) strains UTI89 and CFT073, we deleted the secretin gene present in each cluster. The secretin forms a channel in the outer membrane that is essential for the function of T2S and T4P systems. We compared the secretin deletion mutants with their wild type counterparts using tissue culture assays and the CBA/J mouse model of ascending urinary tract infection. No deficiencies were observed with any of the mutants in adherence, invasion or replication in human bladder or kidney cell lines, but UTI89 ΔhofQ and UTI89 ΔgspD exhibited approximately 2-fold defects in fluxing out of bladder epithelial cells. In the mouse infection model, each of the knockout mutants was able to establish successful infections in the bladder and kidneys by day one post-infection. However, UTI89 ΔhofQ and a CFT073 ΔhofQ ΔyheF double mutant both exhibited defects in colonizing the kidneys by day seven post-infection. Conclusions/Significance Based on our results, we propose that the putative T4P and T2S systems are virulence determinants of UPEC important for persistence in the urinary tract, particularly in renal tissues. PMID:19270734

  2. Structure and copy number of gene clusters related to the pap P-adhesin operon of uropathogenic Escherichia coli.

    PubMed

    Arthur, M; Campanelli, C; Arbeit, R D; Kim, C; Steinbach, S; Johnson, C E; Rubin, R H; Goldstein, R

    1989-02-01

    The structurally related pap and prs operons of the uropathogenic Escherichia coli isolate J96 encode a P and an F adhesin that mediate bacterial attachment to the human P blood group antigen and the Forssman antigen, respectively. Using probes prepared from different segments of the pap operon, Southern blot hybridizations were performed to characterize pap-related sequences of 30 E. coli clinical isolates expressing different adhesin phenotypes. Gene clusters encoding P and F adhesins displayed no restriction site polymorphism in sequences homologous to the papH, papC, and papD genes that encode proteins essential to the transport and polymerization of the subunits of the P-pilus adhesin. In contrast, pap-related genetic elements associated with a null phenotype either lacked homology to the papH, papC, and papD genes or displayed a restriction site polymorphism in this region. Sequences within and surrounding the J96 papG and prsG adhesin genes that determine the binding specificities to the P and F antigens, respectively, were not conserved. However, gene clusters encoding different binding specificities could not be distinguished based on such restriction site polymorphisms. The majority of clinical isolates had more than one copy of pap-related sequences that involved gene clusters similar to the J96 pap operon, as well as genetic elements that were related only to a part of this operon. The implications of this unexpected copy number polymorphism with respect to possible recombination events involving pap-related sequences are discussed.

  3. Partial Purification and Characterization of a Bacteriocin DT24 Produced by Probiotic Vaginal Lactobacillus brevis DT24 and Determination of its Anti-Uropathogenic Escherichia coli Potential.

    PubMed

    Trivedi, Disha; Jena, Prasant Kumar; Patel, Jignesh Kumar; Seshadri, Sriram

    2013-06-01

    The emergence of antibiotic resistance has increased the interest for finding new antimicrobials in the past decade. Probiotic Lactic acid bacteria producing antimicrobial proteins like bacteriocin can be excellent agents for development as novel therapeutic agents and complement to conventional antibiotic therapy. Uropathogenic Escherichia coli, most causative agent of Urinary tract infection, has developed resistance to various antibiotics. In the present investigation, antibacterial substance like bacteriocin (Bacteriocin DT24) produced by probiotic Lactobacillus brevis DT24 from vaginal sample of healthy Indian woman was partially purified and characterized. It was efficiently working against various pathogens, that is, Uropathogenic E. coli, Enterococcus faecium, Enterococcus faecalis and Staphylococcus aureus. The antimicrobial peptide was relatively heat resistant and also active over a broad range of pH 2-10. It has been partially purified by ammonium sulfate precipitation and gel filtration chromatography and checked on reverse-phase high-performance liquid chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of bacteriocin DT24 was approximately 7-kDa protein. The peptide is inactivated by proteolytic enzymes, trypsin and lipase but not when treated with catalase, α-amylase and pepsin. It showed bacteriostatic mode of action against uropathogenic E. coli. Such characteristics indicate that this bacteriocin-producing probiotic may be a potential candidate for alternative agents to control urinary tract infections and other pathogens. PMID:26782739

  4. Quinolones Induce Partial or Total Loss of Pathogenicity Islands in Uropathogenic Escherichia coli by SOS-Dependent or -Independent Pathways, Respectively

    PubMed Central

    Soto, S. M.; Jimenez de Anta, M. T.; Vila, J.

    2006-01-01

    Escherichia coli is the most common microorganism causing urinary tract infections. Quinolone-resistant E. coli strains have fewer virulence factors than quinolone-susceptible strains. Several urovirulence genes are located in pathogenicity islands (PAIs). We investigated the capacity of quinolones to induce loss of virulence factors such as hemolysin, cytotoxic necrotizing factor 1, P fimbriae, and autotransporter Sat included in PAIs in three uropathogenic E. coli strains. In a multistep selection, all strains lost hemolytic capacity at between 1 and 4 passages when they were incubated with subinhibitory concentrations of ciprofloxacin, showing a partial or total loss of the PAI containing the hly (hemolysin) and cnf-1 (cytotoxic necrotizing factor 1) genes. RecA− mutants were obtained from the two E. coli strains with partial or total loss of the PAI. The inactivation of the RecA protein affected only the partial loss of the PAI induced by quinolones. No spontaneous loss of PAIs was observed on incubation in the absence of quinolones in either the wild-type or mutant E. coli strains. Quinolones induce partial or total loss of PAIs in vitro in uropathogenic E. coli by SOS-dependent or -independent pathways, respectively. PMID:16436722

  5. Crystal structure of c5321: a protective antigen present in uropathogenic Escherichia coli strains displaying an SLR fold

    PubMed Central

    2013-01-01

    Background Increasing rates of antimicrobial resistance among uropathogens led, among other efforts, to the application of subtractive reverse vaccinology for the identification of antigens present in extraintestinal pathogenic E. coli (ExPEC) strains but absent or variable in non-pathogenic strains, in a quest for a broadly protective Escherichia coli vaccine. The protein coded by locus c5321 from CFT073 E. coli was identified as one of nine potential vaccine candidates against ExPEC and was able to confer protection with an efficacy of 33% in a mouse model of sepsis. c5321 (known also as EsiB) lacks functional annotation and structurally belongs to the Sel1-like repeat (SLR) family. Herein, as part of the general characterization of this potential antigen, we have focused on its structural properties. Results We report the 1.74 Å-resolution crystal structure of c5321 from CFT073 E. coli determined by Se-Met SAD phasing. The structure is composed of 11 SLR units in a topological organisation that highly resembles that found in HcpC from Helicobacter pylori, with the main difference residing in how the super-helical fold is stabilised. The stabilising effect of disulfide bridges in HcpC is replaced in c5321 by a strengthening of the inter-repeat hydrophobic core. A metal-ion binding site, uncharacteristic of SLR proteins, is detected between SLR units 3 and 4 in the region of the inter-repeat hydrophobic core. Crystal contacts are observed between the C-terminal tail of one molecule and the C-terminal amphipathic groove of a neighbouring one, resembling interactions between ligand and proteins containing tetratricopeptide-like repeats. Conclusions The structure of antigen c5321 presents a mode of stabilization of the SLR fold different from that observed in close homologs of known structure. The location of the metal-ion binding site and the observed crystal contacts suggest a potential role in regulation of conformational flexibility and interaction with yet

  6. Adhesive Fiber Stratification in Uropathogenic Escherichia coli Biofilms Unveils Oxygen-Mediated Control of Type 1 Pili

    PubMed Central

    Floyd, Kyle A.; Moore, Jessica L.; Eberly, Allison R.; Good, James A. D.; Shaffer, Carrie L.; Zaver, Himesh; Almqvist, Fredrik; Skaar, Eric P.; Caprioli, Richard M.; Hadjifrangiskou, Maria

    2015-01-01

    Bacterial biofilms account for a significant number of hospital-acquired infections and complicate treatment options, because bacteria within biofilms are generally more tolerant to antibiotic treatment. This resilience is attributed to transient bacterial subpopulations that arise in response to variations in the microenvironment surrounding the biofilm. Here, we probed the spatial proteome of surface-associated single-species biofilms formed by uropathogenic Escherichia coli (UPEC), the major causative agent of community-acquired and catheter-associated urinary tract infections. We used matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) imaging mass spectrometry (IMS) to analyze the spatial proteome of intact biofilms in situ. MALDI-TOF IMS revealed protein species exhibiting distinct localizations within surface-associated UPEC biofilms, including two adhesive fibers critical for UPEC biofilm formation and virulence: type 1 pili (Fim) localized exclusively to the air-exposed region, while curli amyloid fibers localized to the air-liquid interface. Comparison of cells grown aerobically, fermentatively, or utilizing an alternative terminal electron acceptor showed that the phase-variable fim promoter switched to the “OFF” orientation under oxygen-deplete conditions, leading to marked reduction of type 1 pili on the bacterial cell surface. Conversely, S pili whose expression is inversely related to fim expression were up-regulated under anoxic conditions. Tethering the fim promoter in the “ON” orientation in anaerobically grown cells only restored type 1 pili production in the presence of an alternative terminal electron acceptor beyond oxygen. Together these data support the presence of at least two regulatory mechanisms controlling fim expression in response to oxygen availability and may contribute to the stratification of extracellular matrix components within the biofilm. MALDI IMS facilitated the discovery of these mechanisms

  7. Frequency and organization of papA homologous DNA sequences among uropathogenic digalactoside-binding Escherichia coli strains.

    PubMed

    Denich, K; Craiu, A; Rugo, H; Muralidhar, G; O'Hanley, P

    1991-06-01

    The frequency of selected papA DNA sequences among 89 digalactoside-binding, uropathogenic Escherichia coli strains was evaluated with 12 different synthetic 15-base probes corresponding to papA genes from four digalactoside-binding piliated recombinant strains (HU849, 201B, and 200A). The papA probes encode amino acids which are common at the carboxy terminus of all strains, adjacent to the proximal portion of the intramolecular disulfide loop of strain 210B, or predicted to constitute the type-specific epitope for each of the four recombinant strains or other epitopes of strain HU849. The presence among the strains of DNA sequence homology to the papA probes was determined by in situ colony hybridization. Hybridization data suggest that there is a high frequency of homologous papA DNA sequences corresponding to selected regions of the papA gene from strain HU849 among the clinical strains. The following nucleotide locations which encode portions of the mature HU849 PapA are detected in a high percentage (42 to 70%) of clinical isolates: 208 to 222, 310 to 324, 478 to 492, 517 to 531, 553 to 567, and 679 to 693. These sequences encode portions of the predicted protective, immunogenic, and/or antigenic epitopes of this PapA. The data also indicate considerable heterogeneity of papA sequences among the strains, especially in the region of nucleotide bases corresponding to positions 391 to 418. These oligonucleotides encode the predicted PapA type-specific immunogenic dominant epitope. Determination of the extent of genetic variability in the papA gene among digalactoside-binding strains will require more extensive DNA sequencing of prototypic papA genes, additional hybridization studies employing other papA gene oligonucleotide probes, and assessment of the different pap operons and their copy number in each strain.

  8. Adenylate cyclase and the cyclic AMP receptor protein modulate stress resistance and virulence capacity of uropathogenic Escherichia coli.

    PubMed

    Donovan, Grant T; Norton, J Paul; Bower, Jean M; Mulvey, Matthew A

    2013-01-01

    In many bacteria, the second messenger cyclic AMP (cAMP) interacts with the transcription factor cAMP receptor protein (CRP), forming active cAMP-CRP complexes that can control a multitude of cellular activities, including expanded carbon source utilization, stress response pathways, and virulence. Here, we assessed the role of cAMP-CRP as a regulator of stress resistance and virulence in uropathogenic Escherichia coli (UPEC), the principal cause of urinary tract infections worldwide. Deletion of genes encoding either CRP or CyaA, the enzyme responsible for cAMP synthesis, attenuates the ability of UPEC to colonize the bladder in a mouse infection model, dependent on intact innate host defenses. UPEC mutants lacking cAMP-CRP grow normally in the presence of glucose but are unable to utilize alternate carbon sources like amino acids, the primary nutrients available to UPEC within the urinary tract. Relative to the wild-type UPEC isolate, the cyaA and crp deletion mutants are sensitive to nitrosative stress and the superoxide generator methyl viologen but remarkably resistant to hydrogen peroxide (H(2)O(2)) and acid stress. In the mutant strains, H(2)O(2) resistance correlates with elevated catalase activity attributable in part to enhanced translation of the alternate sigma factor RpoS. Acid resistance was promoted by both RpoS-independent and RpoS-dependent mechanisms, including expression of the RpoS-regulated DNA-binding ferritin-like protein Dps. We conclude that balanced input from many cAMP-CRP-responsive elements, including RpoS, is critical to the ability of UPEC to handle the nutrient limitations and severe environmental stresses present within the mammalian urinary tract.

  9. Lifting the mask: identification of new small molecule inhibitors of uropathogenic Escherichia coli group 2 capsule biogenesis.

    PubMed

    Goller, Carlos C; Arshad, Mehreen; Noah, James W; Ananthan, Subramaniam; Evans, Carrie W; Nebane, N Miranda; Rasmussen, Lynn; Sosa, Melinda; Tower, Nichole A; White, E Lucile; Neuenswander, Benjamin; Porubsky, Patrick; Maki, Brooks E; Rogers, Steven A; Schoenen, Frank; Seed, Patrick C

    2014-01-01

    Uropathogenic Escherichia coli (UPEC) is the leading cause of community-acquired urinary tract infections (UTIs), with over 100 million UTIs occurring annually throughout the world. Increasing antimicrobial resistance among UPEC limits ambulatory care options, delays effective treatment, and may increase overall morbidity and mortality from complications such as urosepsis. The polysaccharide capsules of UPEC are an attractive target a therapeutic, based on their importance in defense against the host immune responses; however, the large number of antigenic types has limited their incorporation into vaccine development. The objective of this study was to identify small-molecule inhibitors of UPEC capsule biogenesis. A large-scale screening effort entailing 338,740 compounds was conducted in a cell-based, phenotypic screen for inhibition of capsule biogenesis in UPEC. The primary and concentration-response assays yielded 29 putative inhibitors of capsule biogenesis, of which 6 were selected for further studies. Secondary confirmatory assays identified two highly active agents, named DU003 and DU011, with 50% inhibitory concentrations of 1.0 µM and 0.69 µM, respectively. Confirmatory assays for capsular antigen and biochemical measurement of capsular sugars verified the inhibitory action of both compounds and demonstrated minimal toxicity and off-target effects. Serum sensitivity assays demonstrated that both compounds produced significant bacterial death upon exposure to active human serum. DU011 administration in mice provided near complete protection against a lethal systemic infection with the prototypic UPEC K1 isolate UTI89. This work has provided a conceptually new class of molecules to combat UPEC infection, and future studies will establish the molecular basis for their action along with efficacy in UTI and other UPEC infections.

  10. Bacterial lysis liberates the neutrophil migration suppressor YbcL from the periplasm of uropathogenic Escherichia coli.

    PubMed

    Lau, Megan E; Danka, Elizabeth S; Tiemann, Kristin M; Hunstad, David A

    2014-12-01

    Uropathogenic Escherichia coli (UPEC) modulates aspects of the innate immune response during urinary tract infection to facilitate bacterial invasion of the bladder epithelium, a requirement for the propagation of infection. For example, UPEC-encoded YbcL suppresses the traversal of bladder epithelia by neutrophils in both an in vitro model and an in vivo murine cystitis model. The suppressive activity of YbcL requires liberation from the bacterial periplasm, though the mechanism of release is undefined. Here we present findings on the site of action of YbcL and demonstrate a novel mode of secretion for a UPEC exoprotein. Suppression of neutrophil migration by purified YbcL(UTI), encoded by cystitis isolate UTI89, required the presence of a uroepithelial layer; YbcL(UTI) did not inhibit neutrophil chemotaxis directly. YbcL(UTI) was released to a greater extent during UPEC infection of uroepithelial cells than during that of neutrophils. Release of YbcL(UTI) was maximal when UPEC and bladder epithelial cells were in close proximity. Established modes of secretion, including outer membrane vesicles, the type II secretion system, and the type IV pilus, were dispensable for YbcL(UTI) release from UPEC. Instead, YbcL(UTI) was liberated during bacterial death, which was augmented upon exposure to bladder epithelial cells, as confirmed by detection of bacterial cytoplasmic proteins and DNA in the supernatant and enumeration of bacteria with compromised membranes. As YbcL(UTI) acts on the uroepithelium to attenuate neutrophil migration, this mode of release may represent a type of altruistic cooperation within a UPEC population during colonization of the urinary tract.

  11. A Comparative Analysis of the Mechanism of Toll-Like Receptor-Disruption by TIR-Containing Protein C from Uropathogenic Escherichia coli

    PubMed Central

    Waldhuber, Anna; Snyder, Greg A.; Römmler, Franziska; Cirl, Christine; Müller, Tina; Xiao, Tsan Sam; Svanborg, Catharina; Miethke, Thomas

    2016-01-01

    The TIR-containing protein C (TcpC) of uropathogenic Escherichia coli strains is a powerful virulence factor by impairing the signaling cascade of Toll-like receptors (TLRs). Several other bacterial pathogens like Salmonella, Yersinia, Staphylococcus aureus but also non-pathogens express similar proteins. We discuss here the pathogenic potential of TcpC and its interaction with TLRs and TLR-adapter proteins on the molecular level and compare its activity with the activity of other bacterial TIR-containing proteins. Finally, we analyze and compare the structure of bacterial TIR-domains with the TIR-domains of TLRs and TLR-adapters. PMID:26938564

  12. Cytotoxic Necrotizing Factor Type 1 of Uropathogenic Escherichia coli Kills Cultured Human Uroepithelial 5637 Cells by an Apoptotic Mechanism

    PubMed Central

    Mills, Melody; Meysick, Karen C.; O'Brien, Alison D.

    2000-01-01

    Pathogenic Escherichia coli associated with urinary tract infections (UTIs) in otherwise healthy individuals frequently produce cytotoxic necrotizing factor type 1 (CNF1), a member of the family of bacterial toxins that target the Rho family of small GTP-binding proteins. To gain insight into the function of CNF1 in the development of E. coli-mediated UTIs, we examined the effects of CNF1 intoxication on a panel of human cell lines derived from physiologically relevant sites (bladder, ureters, and kidneys). We identified one uroepithelial cell line that exhibited a distinctly different CNF1 intoxication phenotype from the prototypic one of multinucleation without cell death that is seen when HEp-2 or other epithelial cells are treated with CNF1. The 5637 bladder cell line detached from the growth surface within 72 h of CNF1 intoxication, a finding that suggested frank cytotoxicity. To determine the basis for the unexpected toxic effect of CNF1 on 5637 cells, we compared the degree of toxin binding, actin fiber formation, and Rho modification with those CNF1-induced events in HEp-2 cells. We found no apparent difference in the amount of CNF1 bound to 5637 cells and HEp-2 cells. Moreover, CNF1 modified Rho, in vivo and in vitro, in both cell types. In contrast, one of the classic responses to CNF1 in HEp-2 and other epithelial cell lines, the formation of actin stress fibers, was markedly absent in 5637 cells. Indeed, actin stress fiber induction by CNF1 did not occur in any of the other human bladder cell lines that we tested (J82, SV-HUC-1, or T24). Furthermore, the appearance of lamellipodia and filopodia in 5637 cells suggested that CNF1 activated the Cdc42 and Rac proteins. Finally, apoptosis was observed in CNF1-intoxicated 5637 cells. If our results with 5637 cells reflect the interaction of CNF1 with the transitional uroepithelium in the human bladder, then CNF1 may be involved in the exfoliative process that occurs in that organ after infection with

  13. Restriction fragment length polymorphism and multiple copies of DNA sequences homologous with probes for P-fimbriae and hemolysin genes among uropathogenic Escherichia coli.

    PubMed

    Hull, S I; Bieler, S; Hull, R A

    1988-03-01

    Hemolysin and P-fimbriae are two virulence traits frequently found together in uropathogenic Escherichia coli. Previous studies have discovered evidence both for linkage between the genes for these traits and for their duplication in the chromosomes of a limited number of strains. To test whether these observations are characteristic of uropathogenic Escherichia coli, the method of DNA hybridization to DNA restriction fragments separated by electrophoresis and transferred to nylon was used to determine copy number of genes for P-fimbriae (pap) among 51 E. coli strains isolated from symptomatic urinary tract infections. Twenty percent of the strains had more than one copy of pap homologous sequences. Fifteen strains, each representing a unique clone, were examined for the presence of sequences homologous with cloned hemolysin genes (hly). Samples of DNA from 14 of the 15 strains hybridized with hly probes. In eight strains the number of copies of pap equalled the number of copies of hly, including one strain with two apparent copies of each. Five strains appeared to have one more copy of pap than of hly, and one strain had an extra copy of hly.

  14. The role of the galU gene of uropathogenic Escherichia coli in modulating macrophage TNF-α response.

    PubMed

    Meyer, Christian; Hoffmann, Christiane; Haas, Rainer; Schubert, Sören

    2015-12-01

    Uropathogenic Escherichia coli (UPEC) are the major cause of urinary tract infections (UTI). These bacteria are equipped with an arsenal of virulence factors, such as siderophores and adhesins enabling UPECs to sufficiently colonize the urinary tract of humans and animals. Such virulence factors manipulate and impair the recognition of UPECs by the host's innate immune system. Among those, factors like the TIR domain containing proteins in E. coli (TcpC) have been described to interfere with the Toll-like receptor 4 signaling cascade. Nevertheless, some UPECs such as strain UTI89 lack TcpC, but also manipulate the innate immune response. By a random mutant-library approach we identified the galU gene of strain UTI89 to be responsible for a reduced immune response of macrophages. Consequently, we created a site directed knockout mutant of the galU gene in strain UTI89. This mutant caused a significantly increased cytokine response when co-incubated with J774A.1 macrophages. This phenotype could be recomplemented in trans by insertion of a galU-expressing plasmid. No differences in the viability of macrophages co-incubated with either the wild-type (WT) or the ΔgalU mutant strain could be observed. Nor could any growth impairment be detected in the ΔgalU mutant compared to WT strain. Hence, the increased cytokine response was not due to differences in the bacterial cytotoxicity or bacterial counts in the assay. Our results also demonstrated a reduction of intracellular counts of UTI89ΔgalU in the infection model. We were able to show a loss of the O-polysaccharide side chain of the ΔgalU mutant LPS. A comparable LPS structure could be generated by the deletion of the waaL gene in the UTI89. This also caused an impaired immune modulation. In contrast, purified LPS was not sufficient to impair cytokine release of macrophages. Moreover, no differences could be detected by applying bacteria inactivated with heat or formalin treatment. From this, we assume that the

  15. Full-Genome Sequence of Escherichia coli K-15KW01, a Uropathogenic E. coli B2 Sequence Type 127 Isolate Harboring a Chromosomally Carried blaCTX-M-15 Gene.

    PubMed

    Zurfluh, Katrin; Tasara, Taurai; Stephan, Roger

    2016-01-01

    We present here the full-genome sequence of Escherichia coli K-15KW01, an extended-spectrum-β-lactamase-producing uropathogenic strain. Assembly and annotation of the draft genome resulted in a 5,154,641-bp chromosome and revealed a chromosomally contained blaCTX-M-15 gene embedded at the right-hand extremity of an ISEcp1 element in a plasmid-like structure (36,907 bp). PMID:27587831

  16. Full-Genome Sequence of Escherichia coli K-15KW01, a Uropathogenic E. coli B2 Sequence Type 127 Isolate Harboring a Chromosomally Carried blaCTX-M-15 Gene

    PubMed Central

    Zurfluh, Katrin; Tasara, Taurai

    2016-01-01

    We present here the full-genome sequence of Escherichia coli K-15KW01, an extended-spectrum-β-lactamase-producing uropathogenic strain. Assembly and annotation of the draft genome resulted in a 5,154,641-bp chromosome and revealed a chromosomally contained blaCTX-M-15 gene embedded at the right-hand extremity of an ISEcp1 element in a plasmid-like structure (36,907 bp). PMID:27587831

  17. Modeling the Inactivation of Intestinal Pathogenic Escherichia coli O157:H7 and Uropathogenic E. coli in Ground Chicken by High Pressure Processing and Thymol.

    PubMed

    Chien, Shih-Yung; Sheen, Shiowshuh; Sommers, Christopher H; Sheen, Lee-Yan

    2016-01-01

    Disease causing Escherichia coli commonly found in meat and poultry include intestinal pathogenic E. coli (iPEC) as well as extraintestinal types such as the Uropathogenic E. coli (UPEC). In this study we compared the resistance of iPEC (O157:H7) to UPEC in chicken meat using High Pressure Processing (HPP) in with (the hurdle concept) and without thymol essential oil as a sensitizer. UPEC was found slightly more resistant than E. coli O157:H7 (iPEC O157:H7) at 450 and 500 MPa. A central composite experimental design was used to evaluate the effect of pressure (300-400 MPa), thymol concentration (100-200 ppm), and pressure-holding time (10-20 min) on the inactivation of iPEC O157:H7 and UPEC in ground chicken. The hurdle approach reduced the high pressure levels and thymol doses imposed on the food matrices and potentially decreased food quality damaged after treatment. The quadratic equations were developed to predict the impact (lethality) on iPEC O157:H7 (R (2) = 0.94) and UPEC (R (2) = 0.98), as well as dimensionless non-linear models [Pr > F (<0.0001)]. Both linear and non-linear models were validated with data obtained from separated experiment points. All models may predict the inactivation/lethality within the same order of accuracy. However, the dimensionless non-linear models showed potential applications with parameters outside the central composite design ranges. The results provide useful information of both iPEC O157:H7 and UPEC in regard to how they may survive HPP in the presence or absence of thymol. The models may further assist regulatory agencies and food industry to assess the potential risk of iPEC O157:H7 and UPEC in ground chicken. PMID:27379050

  18. Modeling the Inactivation of Intestinal Pathogenic Escherichia coli O157:H7 and Uropathogenic E. coli in Ground Chicken by High Pressure Processing and Thymol.

    PubMed

    Chien, Shih-Yung; Sheen, Shiowshuh; Sommers, Christopher H; Sheen, Lee-Yan

    2016-01-01

    Disease causing Escherichia coli commonly found in meat and poultry include intestinal pathogenic E. coli (iPEC) as well as extraintestinal types such as the Uropathogenic E. coli (UPEC). In this study we compared the resistance of iPEC (O157:H7) to UPEC in chicken meat using High Pressure Processing (HPP) in with (the hurdle concept) and without thymol essential oil as a sensitizer. UPEC was found slightly more resistant than E. coli O157:H7 (iPEC O157:H7) at 450 and 500 MPa. A central composite experimental design was used to evaluate the effect of pressure (300-400 MPa), thymol concentration (100-200 ppm), and pressure-holding time (10-20 min) on the inactivation of iPEC O157:H7 and UPEC in ground chicken. The hurdle approach reduced the high pressure levels and thymol doses imposed on the food matrices and potentially decreased food quality damaged after treatment. The quadratic equations were developed to predict the impact (lethality) on iPEC O157:H7 (R (2) = 0.94) and UPEC (R (2) = 0.98), as well as dimensionless non-linear models [Pr > F (<0.0001)]. Both linear and non-linear models were validated with data obtained from separated experiment points. All models may predict the inactivation/lethality within the same order of accuracy. However, the dimensionless non-linear models showed potential applications with parameters outside the central composite design ranges. The results provide useful information of both iPEC O157:H7 and UPEC in regard to how they may survive HPP in the presence or absence of thymol. The models may further assist regulatory agencies and food industry to assess the potential risk of iPEC O157:H7 and UPEC in ground chicken.

  19. Modeling the Inactivation of Intestinal Pathogenic Escherichia coli O157:H7 and Uropathogenic E. coli in Ground Chicken by High Pressure Processing and Thymol

    PubMed Central

    Chien, Shih-Yung; Sheen, Shiowshuh; Sommers, Christopher H.; Sheen, Lee-Yan

    2016-01-01

    Disease causing Escherichia coli commonly found in meat and poultry include intestinal pathogenic E. coli (iPEC) as well as extraintestinal types such as the Uropathogenic E. coli (UPEC). In this study we compared the resistance of iPEC (O157:H7) to UPEC in chicken meat using High Pressure Processing (HPP) in with (the hurdle concept) and without thymol essential oil as a sensitizer. UPEC was found slightly more resistant than E. coli O157:H7 (iPEC O157:H7) at 450 and 500 MPa. A central composite experimental design was used to evaluate the effect of pressure (300–400 MPa), thymol concentration (100–200 ppm), and pressure-holding time (10–20 min) on the inactivation of iPEC O157:H7 and UPEC in ground chicken. The hurdle approach reduced the high pressure levels and thymol doses imposed on the food matrices and potentially decreased food quality damaged after treatment. The quadratic equations were developed to predict the impact (lethality) on iPEC O157:H7 (R2 = 0.94) and UPEC (R2 = 0.98), as well as dimensionless non-linear models [Pr > F (<0.0001)]. Both linear and non-linear models were validated with data obtained from separated experiment points. All models may predict the inactivation/lethality within the same order of accuracy. However, the dimensionless non-linear models showed potential applications with parameters outside the central composite design ranges. The results provide useful information of both iPEC O157:H7 and UPEC in regard to how they may survive HPP in the presence or absence of thymol. The models may further assist regulatory agencies and food industry to assess the potential risk of iPEC O157:H7 and UPEC in ground chicken. PMID:27379050

  20. Type 1 Fimbriae, a Colonization Factor of Uropathogenic Escherichia coli, Are Controlled by the Metabolic Sensor CRP-cAMP

    PubMed Central

    Müller, Claudia M.; Åberg, Anna; Straseviçiene, Jurate; Emődy, Levente; Uhlin, Bernt Eric; Balsalobre, Carlos

    2009-01-01

    Type 1 fimbriae are a crucial factor for the virulence of uropathogenic Escherichia coli during the first steps of infection by mediating adhesion to epithelial cells. They are also required for the consequent colonization of the tissues and for invasion of the uroepithelium. Here, we studied the role of the specialized signal transduction system CRP-cAMP in the regulation of type 1 fimbriation. Although initially discovered by regulating carbohydrate metabolism, the CRP-cAMP complex controls a major regulatory network in Gram-negative bacteria, including a broad subset of genes spread into different functional categories of the cell. Our results indicate that CRP-cAMP plays a dual role in type 1 fimbriation, affecting both the phase variation process and fimA promoter activity, with an overall repressive outcome on fimbriation. The dissection of the regulatory pathway let us conclude that CRP-cAMP negatively affects FimB-mediated recombination by an indirect mechanism that requires DNA gyrase activity. Moreover, the underlying studies revealed that CRP-cAMP controls the expression of another global regulator in Gram-negative bacteria, the leucine-responsive protein Lrp. CRP-cAMP-mediated repression is limiting the switch from the non-fimbriated to the fimbriated state. Consistently, a drop in the intracellular concentration of cAMP due to altered physiological conditions (e.g. growth in presence of glucose) increases the percentage of fimbriated cells in the bacterial population. We also provide evidence that the repression of type 1 fimbriae by CRP-cAMP occurs during fast growth conditions (logarithmic phase) and is alleviated during slow growth (stationary phase), which is consistent with an involvement of type 1 fimbriae in the adaptation to stress conditions by promoting biofilm growth or entry into host cells. Our work suggests that the metabolic sensor CRP-cAMP plays a role in coupling the expression of type 1 fimbriae to environmental conditions, thereby

  1. Phylogenetic Distribution of Virulence Genes Among ESBL-producing Uropathogenic Escherichia coli Isolated from Long-term Hospitalized Patients

    PubMed Central

    Zhao, Ruike; Shi, Jinfang; Shen, Yimin; Li, Yanmeng; Han, Qingzhen; Zhang, Xianfeng; Gu, Guohao

    2015-01-01

    Objectives The present study was aimed to investigate the antibiotic resistance, virulence potential and phylogenetic grouping of ESBL-producing uropathogenic Escherichia coli (EP-UPEC) isolated from long-term hospitalized patients. Materials and Methods EP-UPEC isolates from September 2013 to June 2014 at a tertiary care hospital of China were screened for ESBL-production by the double disk diffusion test. Isolates with ESBL-phenotype were further characterized by antibiotic resistance testing, PCR of different ESBL and virulence genes, and phylogenetic grouping. Results One hundred and twenty EP-UPEC were isolated from long-term hospitalized patients. All EP-UPEC isolates were resistant to Ampicillin, Cefazolin, Cefuroxime, Cefotaxime, Cefoperazone and Ceftriaxone, and the majority of EP-UPEC isolates were resistant to Piperacillin (82.5%), Ciprofloxacin (81.2%), Trimethoprim-Sulfamethoxazole (72.5%). The isolates showed the highest sensitivity against Imipenem (98.4%), Piperacillin/tazobactam (96.7%), Cefoperazone/sulbactam (91.7%), Amikacin (90.8%) and Cefepime (75.8%). Nine different ESBL genotype patterns were observed and CTX-M type was the most prevalent ESBL genotype (42.5%, 51/120). Majority of EP-UPEC isolates possess more than one ESBL genes. EP-UPEC isolates belonged mainly to phylogenetic group B2(36.7%) and D(35.0%). The prevalence of traT, ompT, iss, PAI, afa, fimH and papC were 75.8%, 63.3%, 63.3%, 60.8%, 40.8%, 19.2% and 6.7%, respectively. The number of virulence genes (VGs) detected was significantly higher in group B2 than in group A (ANOVA, p<0.001), group B1(ANOVA, p= 0.012) and D (ANOVA, p<0.001). Conclusions EP-UPEC strains showed multidrug resistance and co-resistance to other non β-lactam antibiotics. CTX-M was the most prevalent ESBL genotype and majority of EP-UPEC strains more than one ESBL genes. EP-UPEC strains belonged mainly to phylogenetic group B2 and D, and most of the virulence genes were more prevalent in group B2. PMID

  2. Prevalence and Antibiotic Susceptibility Patterns of Extended-Spectrum ß-Lactamase and Metallo-ß-Lactamase-Producing Uropathogenic Escherichia coli Isolates.

    PubMed

    Ghadiri, Hamed; Vaez, Hamid; Razavi-Azarkhiavi, Kamal; Rezaee, Ramin; Haji-Noormohammadi, Mehdi; Rahimi, Ali Asghar; Vaez, Vahid; Kalantar, Enayatollah

    2014-01-01

    Healthcare professionals worldwide have expressed concern over infections by extended-spectrum ß-lactamase (ESBL) and metallo-ß-lactamase (MBL)-producing bacteria. We evaluated the prevalence of ESBL- and MBL-producing Escherichia coli (E. coli) isolated from community-acquired urinary tract infections (UTIs) and their antibiotic-resistance profiles at 3 private laboratories in Tehran, Iran. E. coli isolates were mostly susceptible to meropenem (90.4%) and imipenem (90.0%), followed by amikacin (89.0%) and gentamicin (84.7%). Moreover, we detected that, of the E. coli isolates, 67 (22.3%) were ESBL producers and 21 (7.0%) of E. coli isolates were MBL positive via the imipenem-ethylenediaminetetraacetic acid (EDTA) combined disc test. This report is the first, to our knowledge, on the prevalence of MBL-producing uropathogenic E. coli (UPEC) strains in Iran. The antibiotic resistance of E. coli isolates revealed that 122 (40.7%) were multidrug resistant. The high number of antibiotic-resistant and ß-lactamase-producing UPEC strains necessitates further attention and consideration, particularly MBL-producing strains.

  3. [Evaluation of the adhesive characteristics of uropathogenic escherichia coli strains in patients with spinal cord injuries].

    PubMed

    Osipova, E V; Shipitsina, I V

    2014-01-01

    The adhesion characteristics of 9 clinical E.coli strains, isolated from the urine of 9 patients with spinal cord injuries in late period were evaluated. Patient age was 21 to 54 years. Neurogenic urination disordes observed in patients were the result of a spinal injury in the cervical (5 patients), thoracic (2 patients) and thoracolumbar (2 patients) spine. The duration of disease ranged from 2 to 12 years. Despite primarily a low adhesion activity of tested strains, the formation of biofilm occurs on the surfaces having both hydrophobic (polystyrene) and hydrophilic (cover glass) properties. After 24 h, according to the photometric evaluation, 7 of 9 strains had weak, 1 - medium, and 1 - high ability to form biofilms. After 48 hours, only 4 strains had low ability to form biofilms, of whom 2 had an increase ability compared to the previous period of observation. Other strains possess the medium ability to form biofilm. When quantifying the ability of bacteria to form biofilms on the surface of the cover glass, it was revealed that a large fraction of the area of the field of view was accounted for microcolonies with size 10 microm2 at 24 hours, and microcolony with size from 100 to 1000 microm2 at 48 h. There were number of significant correlations between parameters studied. After 24 h, the correlation coefficient between the optical density (OD630) and the number, OD630 and proportion of microcolonies with size 10 to 10000 microm2 varied from 0.79 to 0.9. After 48 hours, there was a direct correlation between the OD630 and the number (r = 0.73, P = 0.025), OD630 and proportion (r = 0.81, P = 0.009) of microcolonies with size 1,000 to 10,000 mkm2.

  4. Genetic structure and distribution of four pathogenicity islands (PAI I(536) to PAI IV(536)) of uropathogenic Escherichia coli strain 536.

    PubMed

    Dobrindt, Ulrich; Blum-Oehler, Gabriele; Nagy, Gabor; Schneider, György; Johann, André; Gottschalk, Gerhard; Hacker, Jörg

    2002-11-01

    For the uropathogenic Escherichia coli strain 536 (O6:K15:H31), the DNA sequences of three pathogenicity islands (PAIs) (PAI I(536) to PAI III(536)) and their flanking regions (about 270 kb) were determined to further characterize the virulence potential of this strain. PAI I(536) to PAI III(536) exhibit features typical of PAIs, such as (i) association with tRNA-encoding genes; (ii) G+C content differing from that of the host genome; (iii) flanking repeat structures; (iv) a mosaic-like structure comprising a multitude of functional, truncated, and nonfunctional putative open reading frames (ORFs) with known or unknown functions; and (v) the presence of many fragments of mobile genetic elements. PAI I(536) to PAI III(536) range between 68 and 102 kb in size. Although these islands contain several ORFs and known virulence determinants described for PAIs of other extraintestinal pathogenic E. coli (ExPEC) isolates, they also consist of as-yet-unidentified ORFs encoding putative virulence factors. The genetic structure of PAI IV(536), which represents the core element of the so-called high-pathogenicity island encoding a siderophore system initially identified in pathogenic yersiniae, was further characterized by sample sequencing. For the first time, multiple PAI sequences (PAI I(536) to PAI IV(536)) in uropathogenic E. coli were studied and their presence in several wild-type E. coli isolates was extensively investigated. The results obtained suggest that these PAIs or at least large fragments thereof are detectable in other pathogenic E. coli isolates. These results support our view that the acquisition of large DNA regions, such as PAIs, by horizontal gene transfer is an important factor for the evolution of bacterial pathogens.

  5. Impact of UV and Peracetic Acid Disinfection on the Prevalence of Virulence and Antimicrobial Resistance Genes in Uropathogenic Escherichia coli in Wastewater Effluents

    PubMed Central

    Biswal, Basanta Kumar; Khairallah, Ramzi; Bibi, Kareem; Mazza, Alberto; Gehr, Ronald; Masson, Luke

    2014-01-01

    Wastewater discharges may increase the populations of pathogens, including Escherichia coli, and of antimicrobial-resistant strains in receiving waters. This study investigated the impact of UV and peracetic acid (PAA) disinfection on the prevalence of virulence and antimicrobial resistance genes in uropathogenic Escherichia coli (UPEC), the most abundant E. coli pathotype in municipal wastewaters. Laboratory disinfection experiments were conducted on wastewater treated by physicochemical, activated sludge, or biofiltration processes; 1,766 E. coli isolates were obtained for the evaluation. The target disinfection level was 200 CFU/100 ml, resulting in UV and PAA doses of 7 to 30 mJ/cm2 and 0.9 to 2.0 mg/liter, respectively. The proportions of UPECs were reduced in all samples after disinfection, with an average reduction by UV of 55% (range, 22% to 80%) and by PAA of 52% (range, 11% to 100%). Analysis of urovirulence genes revealed that the decline in the UPEC populations was not associated with any particular virulence factor. A positive association was found between the occurrence of urovirulence and antimicrobial resistance genes (ARGs). However, the changes in the prevalence of ARGs in potential UPECs were different following disinfection, i.e., UV appears to have had no effect, while PAA significantly reduced the ARG levels. Thus, this study showed that both UV and PAA disinfections reduced the proportion of UPECs and that PAA disinfection also reduced the proportion of antimicrobial resistance gene-carrying UPEC pathotypes in municipal wastewaters. PMID:24727265

  6. Impact of UV and peracetic acid disinfection on the prevalence of virulence and antimicrobial resistance genes in uropathogenic Escherichia coli in wastewater effluents.

    PubMed

    Biswal, Basanta Kumar; Khairallah, Ramzi; Bibi, Kareem; Mazza, Alberto; Gehr, Ronald; Masson, Luke; Frigon, Dominic

    2014-06-01

    Wastewater discharges may increase the populations of pathogens, including Escherichia coli, and of antimicrobial-resistant strains in receiving waters. This study investigated the impact of UV and peracetic acid (PAA) disinfection on the prevalence of virulence and antimicrobial resistance genes in uropathogenic Escherichia coli (UPEC), the most abundant E. coli pathotype in municipal wastewaters. Laboratory disinfection experiments were conducted on wastewater treated by physicochemical, activated sludge, or biofiltration processes; 1,766 E. coli isolates were obtained for the evaluation. The target disinfection level was 200 CFU/100 ml, resulting in UV and PAA doses of 7 to 30 mJ/cm(2) and 0.9 to 2.0 mg/liter, respectively. The proportions of UPECs were reduced in all samples after disinfection, with an average reduction by UV of 55% (range, 22% to 80%) and by PAA of 52% (range, 11% to 100%). Analysis of urovirulence genes revealed that the decline in the UPEC populations was not associated with any particular virulence factor. A positive association was found between the occurrence of urovirulence and antimicrobial resistance genes (ARGs). However, the changes in the prevalence of ARGs in potential UPECs were different following disinfection, i.e., UV appears to have had no effect, while PAA significantly reduced the ARG levels. Thus, this study showed that both UV and PAA disinfections reduced the proportion of UPECs and that PAA disinfection also reduced the proportion of antimicrobial resistance gene-carrying UPEC pathotypes in municipal wastewaters. PMID:24727265

  7. Regulation of Expression of Uropathogenic Escherichia coli Nonfimbrial Adhesin TosA by PapB Homolog TosR in Conjunction with H-NS and Lrp.

    PubMed

    Engstrom, Michael D; Mobley, Harry L T

    2016-01-11

    Urinary tract infections (UTIs) are a major burden to human health. The overwhelming majority of UTIs are caused by uropathogenic Escherichia coli (UPEC) strains. Unlike some pathogens, UPEC strains do not have a fixed core set of virulence and fitness factors but do have a variety of adhesins and regulatory pathways. One such UPEC adhesin is the nonfimbrial adhesin TosA, which mediates adherence to the epithelium of the upper urinary tract. The tos operon is AT rich, resides on pathogenicity island aspV, and is not expressed under laboratory conditions. Because of this, we hypothesized that tosA expression is silenced by H-NS. Lrp, based on its prominent function in the regulation of other adhesins, is also hypothesized to contribute to tos operon regulation. Using a variety of in vitro techniques, we mapped both the tos operon promoter and TosR binding sites. We have now identified TosR as a dual regulator of the tos operon, which could control the tos operon in association with H-NS and Lrp. H-NS is a negative regulator of the tos operon, and Lrp positively regulates the tos operon. Exogenous leucine also inhibits Lrp-mediated tos operon positive regulation. In addition, TosR binds to the pap operon, which encodes another important UPEC adhesin, P fimbria. Induction of TosR synthesis reduces production of P fimbria. These studies advance our knowledge of regulation of adhesin expression associated with uropathogen colonization of a host.

  8. SDS-PAGE Analysis of the Outer Membrane Proteins of Uropathogenic Escherichia coli Isolated from Patients in Different Wards of Nemazee Hospital, Shiraz, Iran

    PubMed Central

    Dehghani, Behzad; Mottamedifar, Mohammad; Khoshkharam-Roodmajani, Hossein; Hassanzadeh, Amir; Zomorrodian, Kamyar; Rahimi, Amir

    2016-01-01

    Background: Outer membrane proteins (OMPs) constitute the main structure and about half of the cell wall of Gram-negative bacteria. The OMPs of Escherichia coli (E. coli) play an important role in its drug resistance. Previous studies have shown that the OMPs of E. coli enhance its pathogenic effects by helping the bacterium to evade the immune defense and promote its adsorption to host cells. We sought to compare E. coli isolates collected from different hospital wards and to perform a primary investigation of the association between the serotypes and profiles of their OMPs. We also aimed to detect the diversity of the E. coli isolates from the hospitalized patients. Methods: A total of 115 isolates of E. coli were collected from patients hospitalized in Nemazee Hospital, Shiraz, Iran. After biochemical and serological tests, OMPs were extracted by using glass beads and N-Lauroylsarcosine sodium. OMP typing was done by 10% SDS-PAGE and Coomassie brilliant blue staining. In terms of the number of protein bands, OMP-I was detected with 2 bands, OMP-α with 3 bands, and OMP-β with1 band. Results: Of the 115 isolates, 103 were OMP-I and 12 were OMP-α; none of the isolates belonged to OMP-β. Our statistical analyses showed a relationship between OMP patterns and other factors, including hospital wards and source of samples. Serotyping showed that the majority of the isolates were O128. Conclusion: Our results demonstrated some similarities between the OMP band patterns of the analyzed groups of E. coli. Of all the OMPs in the isolates from the hospitalized and outpatient department patients, OmpA and OmpC were the most prevalent proteins in the outer membrane of the studied uropathogenic E. coli. PMID:27582589

  9. Multilocus Sequence Typing and Virulence Profiles in Uropathogenic Escherichia coli Isolated from Cats in the United States

    PubMed Central

    Liu, Xiaoqiang; Thungrat, Kamoltip; Boothe, Dawn M.

    2015-01-01

    The population structure, virulence, and antimicrobial resistance of uropathogenic E. coli (UPEC) from cats are rarely characterized. The aim of this study was to compare and characterize the UPEC isolated from cats in four geographic regions of USA in terms of their multilocus sequence typing (MLST), virulence profiles, clinical signs, antimicrobial resistance and phylogenetic grouping. The results showed that a total of 74 E. coli isolates were typed to 40 sequence types with 10 being novel. The most frequent phylogenetic group was B2 (n = 57). The most frequent sequence types were ST73 (n = 12) and ST83 (n = 6), ST73 was represented by four multidrug resistant (MDR) and eight non-multidrug resistant (SDR) isolates, and ST83 were significantly more likely to exhibit no drug resistant (NDR) isolates carrying the highest number of virulence genes. Additionally, MDR isolates were more diverse, and followed by SDR and NDR isolates in regards to the distribution of the STs. afa/draBC was the most prevalent among the 29 virulence-associated genes. Linking virulence profile and antimicrobial resistance, the majority of virulence-associated genes tested were more prevalent in NDR isolates, and followed by SDR and MDR isolates. Twenty (50%) MLST types in this study have previously been associated with human isolates, suggesting that these STs are potentially zoonotic. Our data enhanced the understanding of E. coli population structure and virulence association from cats. The diverse and various combinations of virulence-associated genes implied that the infection control may be challenging. PMID:26587840

  10. Uropathogenic Escherichia coli (UPEC) induced antimicrobial gene expression in the male reproductive tract of rat: evaluation of the potential of Defensin 21 to limit infection.

    PubMed

    Biswas, B; Bhushan, S; Rajesh, A; Suraj, S K; Lu, Y; Meinhardt, A; Yenugu, S

    2015-03-01

    Escherichia coli (E. coli) is a common pathogen in epididymitis, which represents a prevalent entity in male reproductive tract infections (RTI). Although current treatment regimens using antibiotics are satisfactory, development of antimicrobial resistance by the pathogen represents a challenge in the management of RTI. Hence, identification of antimicrobial peptides as alternatives to antibiotics has gained importance. We demonstrate that in a rat epididymo-orchitis model induced with uropathogenic E. coli (UPEC) strain MTCC 729, the expression of defensins and defensin-like Spag11 genes are induced in the epididymis and testes. The induction of antimicrobial gene expression is paralleled by phosphorylation of the NF-kB subunit p65 and the inhibitor of NFkB (IkB-alpha), decreased levels of histone deacetylase 1 and increased methylation of Histone 3, indicating the role of classical Toll-like receptor mediated signaling and epigenetic regulation. Recombinant Defensin 21, when administered to UPEC-infected rats, substantially reduced the bacterial load in the epididymis and testis and proved to be more effective than gentamycin. The ability of Defensin 21 to limit RTI provides support that antibacterial proteins of the male reproductive tract may be used as potential alternatives to antibiotics in treatment of this disease.

  11. Role of Hypoxia Inducible Factor-1α (HIF-1α) in Innate Defense against Uropathogenic Escherichia coli Infection

    PubMed Central

    Lin, Ann E.; Beasley, Federico C.; Olson, Joshua; Keller, Nadia; Shalwitz, Robert A.; Hannan, Thomas J.; Hultgren, Scott J.; Nizet, Victor

    2015-01-01

    Uropathogenic E. coli (UPEC) is the primary cause of urinary tract infections (UTI) affecting approximately 150 million people worldwide. Here, we revealed the importance of transcriptional regulator hypoxia-inducible factor-1 α subunit (HIF-1α) in innate defense against UPEC-mediated UTI. The effects of AKB-4924, a HIF-1α stabilizing agent, were studied using human uroepithelial cells (5637) and a murine UTI model. UPEC adherence and invasion were significantly reduced in 5637 cells when HIF-1α protein was allowed to accumulate. Uroepithelial cells treated with AKB-4924 also experienced reduced cell death and exfoliation upon UPEC challenge. In vivo, fewer UPEC were recovered from the urine, bladders and kidneys of mice treated transurethrally with AKB-4924, whereas increased bacteria were recovered from bladders of mice with a HIF-1α deletion. Bladders and kidneys of AKB-4924 treated mice developed less inflammation as evidenced by decreased pro-inflammatory cytokine release and neutrophil activity. AKB-4924 impairs infection in uroepithelial cells and bladders, and could be correlated with enhanced production of nitric oxide and antimicrobial peptides cathelicidin and β-defensin-2. We conclude that HIF-1α transcriptional regulation plays a key role in defense of the urinary tract against UPEC infection, and that pharmacological HIF-1α boosting could be explored further as an adjunctive therapy strategy for serious or recurrent UTI. PMID:25927232

  12. Role of Hypoxia Inducible Factor-1α (HIF-1α) in Innate Defense against Uropathogenic Escherichia coli Infection.

    PubMed

    Lin, Ann E; Beasley, Federico C; Olson, Joshua; Keller, Nadia; Shalwitz, Robert A; Hannan, Thomas J; Hultgren, Scott J; Nizet, Victor

    2015-04-01

    Uropathogenic E. coli (UPEC) is the primary cause of urinary tract infections (UTI) affecting approximately 150 million people worldwide. Here, we revealed the importance of transcriptional regulator hypoxia-inducible factor-1 α subunit (HIF-1α) in innate defense against UPEC-mediated UTI. The effects of AKB-4924, a HIF-1α stabilizing agent, were studied using human uroepithelial cells (5637) and a murine UTI model. UPEC adherence and invasion were significantly reduced in 5637 cells when HIF-1α protein was allowed to accumulate. Uroepithelial cells treated with AKB-4924 also experienced reduced cell death and exfoliation upon UPEC challenge. In vivo, fewer UPEC were recovered from the urine, bladders and kidneys of mice treated transurethrally with AKB-4924, whereas increased bacteria were recovered from bladders of mice with a HIF-1α deletion. Bladders and kidneys of AKB-4924 treated mice developed less inflammation as evidenced by decreased pro-inflammatory cytokine release and neutrophil activity. AKB-4924 impairs infection in uroepithelial cells and bladders, and could be correlated with enhanced production of nitric oxide and antimicrobial peptides cathelicidin and β-defensin-2. We conclude that HIF-1α transcriptional regulation plays a key role in defense of the urinary tract against UPEC infection, and that pharmacological HIF-1α boosting could be explored further as an adjunctive therapy strategy for serious or recurrent UTI.

  13. Dissemination of Extended-Spectrum β-Lactamases and Quinolone Resistance Genes Among Clinical Isolates of Uropathogenic Escherichia coli in Children

    PubMed Central

    Sedighi, Iraj; Arabestani, Mohammad Reza; Rahimbakhsh, Ali; Karimitabar, Zahra; Alikhani, Mohammad Yousef

    2015-01-01

    Background: Urinary tract infection (UTI) is one of the most common childhood bacterial infections and Escherichia coli is the major pathogen. Producing β-lactamase enzymes are the most common mechanism of bacterial resistance. Objectives: This study aimed to determine the prevalence of Extended-Spectrum β-Lactamases (ESBLs) and Quinolone Resistance (qnr) genes in E. coli strains isolated from UTIs. Materials and Methods: In this study, a total of 120 isolates of E. coli from urinary tract infections of the children were collected at Besat Hospital in Hamadan, Iran, from October 2010 to October 2011. The bacterial isolates were identified by standard biochemical methods. Antimicrobial susceptibilities were determined by disk diffusion method, and ESBLs-producing was confirmed phenotypically using the double-disk synergy (DDS) test. The presence and identification of ESBLs and qnr genes were determined by Polymerase Chain Reaction (PCR). Results: The highest sensitivity was seen to imipenem (96.7%), amikacin (92.5%), nitrofurantoin (93.3%), ofloxacin (81.7%), gentamicin norfloxacin (70.8%), and ciprofloxacin (79.2%). In contrast, the highest rate of resistance was seen to co-trimoxazole (77%) and nalidixic acid (40.9%). The results showed that 6 (2.18%) and 4 (1.12%) isolates of ESBL-producing E. coli were positive with respect to having qnrB and qnrS genes, respectively. No isolates was found to have qnrA. Conclusions: CTX-M was the most prevalent ESBL genotype in uropathogenic E. coli (UPEC) isolated from UTI. In addition, a high frequency of qnr genes among ESBL-producing E. coli was identified in this study. In order to avoid treatment failures, we recommend using phenotypic and molecular methods to diagnose these enzymes and qnr genes. PMID:26421128

  14. Intramacrophage survival of uropathogenic Escherichia coli: differences between diverse clinical isolates and between mouse and human macrophages.

    PubMed

    Bokil, Nilesh J; Totsika, Makrina; Carey, Alison J; Stacey, Katryn J; Hancock, Viktoria; Saunders, Bernadette M; Ravasi, Timothy; Ulett, Glen C; Schembri, Mark A; Sweet, Matthew J

    2011-11-01

    Uropathogenic E. coli (UPEC) are the primary cause of urinary tract infections. Recent studies have demonstrated that UPEC can invade and replicate within epithelial cells, suggesting that this bacterial pathogen may occupy an intracellular niche within the host. Given that many intracellular pathogens target macrophages, we assessed the interactions between UPEC and macrophages. Colonization of the mouse bladder by UPEC strain CFT073 resulted in increased expression of myeloid-restricted genes, consistent with the recruitment of inflammatory macrophages to the site of infection. In in vitro assays, CFT073 was able to survive within primary mouse bone marrow-derived macrophages (BMM) up to 24h post-infection. Three additional well-characterized clinical UPEC isolates associated with distinct UTI symptomatologies displayed variable long-term survival within BMM. UPEC strains UTI89 and VR50, originally isolated from patients with cystitis and asymptomatic bacteriuria respectively, showed elevated bacterial loads in BMM at 24h post-infection as compared to CFT073 and the asymptomatic bacteriuria strain 83972. These differences did not correlate with differential effects on macrophage survival or initial uptake of bacteria. E. coli UTI89 localized to a Lamp1(+) vesicular compartment within BMM. In contrast to survival within mouse BMM, intracellular bacterial loads of VR50 were low in both human monocyte-derived macrophages (HMDM) and in human T24 bladder epithelial cells. Collectively, these data suggest that some UPEC isolates may subvert macrophage anti-microbial pathways, and that host species differences may impact on intracellular UPEC survival.

  15. Regulation of Type 1 Fimbriae by Unlinked FimB- and FimE-Like Recombinases in Uropathogenic Escherichia coli Strain CFT073

    PubMed Central

    Bryan, Andrew; Roesch, Paula; Davis, Lindsay; Moritz, Rebecca; Pellett, Shahaireen; Welch, Rodney A.

    2006-01-01

    Genomic DNA sequence analysis of the uropathogenic Escherichia coli strain CFT073 revealed that besides the fimB and fimE recombinase genes that control the type 1 pilus fim phase switch, there are three additional fimB- and fimE-like genes: ipuA, ipuB, and ipbA. Alignment of the predicted amino acid sequences showed that the five recombinases range in sequence similarity from 63 to 70%. An epidemiological survey indicates that ipuA and ipuB are present and linked next to the dsdCXA locus in 24 of 67 uropathogenic E. coli strains but are found in only 1 of 15 normal human fecal isolates. The ipbA sequence located next to the betABIT locus was found in 42 of 67 uropathogenic isolates and 8 of 15 of the commensal strains. We show that two of these recombinases, those encoded by ipuA and ipbA, can function at the type 1 pilus fim switch. In a CFT073 deletion mutant lacking all five recombinase genes, recombinant ipuA or ipbA provided in trans inverted the fim element from the off state to the on state. When a fim OFF CFT073 ΔfimBE mutant was used to infect the urinary tracts of mice, a switch to the fim on state was detected within 24 h in bacteria recovered from urine, the bladder, and the kidneys. A fim OFF CFT073 ΔfimBE ipuB ipbA mutant also demonstrated the ability to switch from the fim off state to the on state during mouse infection. CFT073 recombinase mutants derived from isolates in either the fim on or off state showed a reciprocal relationship for motility. Switches from a nonmotile to a motile phenotype and from a fim on to off genotype were observed in fim ON CFT073 ΔfimBE ipuAB ipbA mutants when ipuA or fimB was provided in trans. Together these results indicate that ipuA has fimB-like on-to-off and off-to-on fim switching activity and that ipbA has the ability to switch fim from the off to the on orientation. PMID:16428754

  16. Detection of pap, sfa, afa, foc, and fim Adhesin-Encoding Operons in Uropathogenic Escherichia coli Isolates Collected From Patients With Urinary Tract Infection

    PubMed Central

    Rahdar, Masoud; Rashki, Ahmad; Miri, Hamid Reza; Rashki Ghalehnoo, Mehdi

    2015-01-01

    Background: Uropathogenic Escherichia coli (UPEC) with its virulence factors is the most prevalent cause of urinary tract infection (UTI). Objectives; This study aimed to determine the occurrence of fim, pap, sfa, and afa genes among 100 UPEC isolates collected from patients diagnosed with UTI. Materials and Methods A total of 100 UPEC isolates were obtained from urine samples of patients with UTI. The prevalence of 5 virulence genes encoding type 1 fimbriae (fimH), pili associated with pyelonephritis (pap), S and F1C fimbriae (sfa and foc) and afimbrial adhesins (afa) were determined through PCR method. We also investigated the phylogenetic background of all isolates. In addition, the distribution of adhesin-encoding operons between the phylogroups was assessed. Results: The prevalence of genes encoding for fimbrial adhesive systems was 95% for fim, 57% for pap, 16% for foc, and 81% for sfa. The operons encoding for afa afimbrial adhesins were identified in 12% of isolates. The various combinations of detected genes were designated as virulence patterns. The fim gene, which occurred in strains from all phylogenetic groups (A, B1, B2, and D) was evaluated and no significant differences were found among these groups. Conversely, significant differences were observed in relation to pap, afa, foc, and sfa operons. Conclusions: These results indicate that the PCR method is a powerful genotypic assay for the detection of adhesin-encoding operons. Thus, this assay can be recommended for clinical use to detect virulent urinary E. coli strains, as well as epidemiological studies. PMID:26464770

  17. Comprehensive mutagenesis of the fimS promoter regulatory switch reveals novel regulation of type 1 pili in uropathogenic Escherichia coli

    PubMed Central

    Zhang, Huibin; Susanto, Teodorus T.; Wan, Yue

    2016-01-01

    Type 1 pili (T1P) are major virulence factors for uropathogenic Escherichia coli (UPEC), which cause both acute and recurrent urinary tract infections. T1P expression therefore is of direct relevance for disease. T1P are phase variable (both piliated and nonpiliated bacteria exist in a clonal population) and are controlled by an invertible DNA switch (fimS), which contains the promoter for the fim operon encoding T1P. Inversion of fimS is stochastic but may be biased by environmental conditions and other signals that ultimately converge at fimS itself. Previous studies of fimS sequences important for T1P phase variation have focused on laboratory-adapted E. coli strains and have been limited in the number of mutations or by alteration of the fimS genomic context. We surmounted these limitations by using saturating genomic mutagenesis of fimS coupled with accurate sequencing to detect both mutations and phase status simultaneously. In addition to the sequences known to be important for biasing fimS inversion, our method also identifies a previously unknown pair of 5′ UTR inverted repeats that act by altering the relative fimA levels to control phase variation. Thus we have uncovered an additional layer of T1P regulation potentially impacting virulence and the coordinate expression of multiple pilus systems. PMID:27035967

  18. A unique arabinose 5-phosphate isomerase found within a genomic island associated with the uropathogenicity of Escherichia coli CFT073.

    PubMed

    Mosberg, Joshua A; Yep, Alejandra; Meredith, Timothy C; Smith, Sara; Wang, Pan-Fen; Holler, Tod P; Mobley, Harry L T; Woodard, Ronald W

    2011-06-01

    Previous studies showed that deletion of genes c3405 to c3410 from PAI-metV, a genomic island from Escherichia coli CFT073, results in a strain that fails to compete with wild-type CFT073 after a transurethral cochallenge in mice and is deficient in the ability to independently colonize the mouse kidney. Our analysis of c3405 to c3410 suggests that these genes constitute an operon with a role in the internalization and utilization of an unknown carbohydrate. This operon is not found in E. coli K-12 but is present in a small number of pathogenic E. coli and Shigella boydii strains. One of the genes, c3406, encodes a protein with significant homology to the sugar isomerase domain of arabinose 5-phosphate isomerases but lacking the tandem cystathionine beta-synthase domains found in the other arabinose 5-phosphate isomerases of E. coli. We prepared recombinant c3406 protein, found it to possess arabinose 5-phosphate isomerase activity, and characterized this activity in detail. We also constructed a c3406 deletion mutant of E. coli CFT073 and demonstrated that this deletion mutant was still able to compete with wild-type CFT073 in a transurethral cochallenge in mice and could colonize the mouse kidney. These results demonstrate that the presence of c3406 is not essential for a pathogenic phenotype.

  19. Inhibitors of TonB function identified by a high-throughput screen for inhibitors of iron acquisition in uropathogenic Escherichia coli CFT073.

    PubMed

    Yep, Alejandra; McQuade, Thomas; Kirchhoff, Paul; Larsen, Martha; Mobley, Harry L T

    2014-02-25

    The urinary tract is one of the most common sites of infection in humans, and uropathogenic Escherichia coli (UPEC) is the main causative agent of urinary tract infections. Bacteria colonizing the urinary tract face extremely low iron availability. To counteract this, UPEC expresses a wide variety of iron acquisition systems. To exploit iron acquisition in UPEC as a global target for small-molecule inhibition, we developed and carried out a whole-cell growth-based high throughput screen of 149,243 compounds. Our primary assay was carried out under iron-limiting conditions. Hits in the primary screen were assayed using two counterscreens that ruled out iron chelators and compounds that inhibit growth by means other than inhibition of iron acquisition. We determined dose-response curves under two different iron conditions and purchased fresh compounds for selected hits. After retesting dose-response relationships, we identified 16 compounds that arrest growth of UPEC only under iron-limiting conditions. All compounds are bacteriostatic and do not inhibit proton motive force. A loss-of-target strategy was employed to identify the cellular target of these inhibitors. Two compounds lost inhibitory activity against a strain lacking TonB and were shown to inhibit irreversible adsorption of a TonB-dependent bacteriophage. Our results validate iron acquisition as a target for antibacterial strategies against UPEC and identify TonB as one of the cellular targets. IMPORTANCE Half of women will suffer at least one episode of urinary tract infection (UTI) during their lifetime. The current treatment for UTI involves antibiotic therapy. Resistance to currently used antibiotics has steadily increased over the last decade, generating a pressing need for the development of new therapeutic agents. Since iron is essential for colonization and scarce in the urinary tract, targeting iron acquisition would seem to be an attractive strategy. However, the multiplicity and redundancy of

  20. In vitro potency and efficacy favor later generation fluoroquinolones for treatment of canine and feline Escherichia coli uropathogens in the United States.

    PubMed

    Liu, Xiaoqiang; Boothe, Dawn M; Jin, Yaping; Thungrat, Kamoltip

    2013-02-01

    Information regarding in vitro activity of newer fluoroquinolones (FQs) is limited despite increasing resistance in canine or feline pathogenic Escherichia coli (E. coli). This study describes in vitro potency and efficacy toward E. coli of seven FQs grouped according to similarities in chemical structure: enrofloxacin, ciprofloxacin, orbifloxacin (first-group), levofloxacin, marbofloxacin (second-group) and pradofloxacin, moxifloxacin (third-group; latest S, S-pyrrolidino-piperidine at C-7). Potency measures included minimum inhibitory concentration (MIC) (geometric mean MIC, MIC(50), MIC(90)); and mutant prevention concentration (MPC) for FQ susceptible isolates only. In vitro efficacy measures included relative susceptibility (MIC(BP-S):MIC) or resistance (MIC:MIC(BP-R)) and mutant selection window (MSW) (MPC:MIC). For enrofloxacin susceptible isolates, mean MIC (μg/ml) was least for each third-group drug and ciprofloxacin and greatest for enrofloxacin and orbifloxacin (P = 0.006). For enrofloxacin susceptible isolates, MPC were below MIC:MIC(BP-R) and least for pradofloxacin (0.29 ± 0.16 μg/ml) and greatest for enrofloxacin (1.55 ± 0.55 μg/ml) (P = 0.006). MSW was least for pradofloxacin (55 ± 30) and greatest for ciprofloxacin (152 ± 76) (P = 0.0024). MIC(BP-S):MIC was greatest (P = 0.025) for pradofloxacin (190.1 ± 0.61) and least for enrofloxacin (23.53 ± 0.83). For FQ susceptible isolates, FQs MIC:MIC(BP-R) may serve as a surrogate for MPC. Because in vitro efficacy was greatest for pradofloxacin; it might be preferred for treatment of urinary tract infections (UTIs) associated with FQ susceptible E. coli uropathogens.

  1. Identification of antigen Ag43 in uropathogenic Escherichia coli Dr+ strains and defining its role in the pathogenesis of urinary tract infections.

    PubMed

    Zalewska-Piatek, Beata; Zalewska-Piatek, Rafał; Olszewski, Marcin; Kur, Józef

    2015-05-01

    Urinary tract infections (UTIs) caused by uropathogenic Escherichia coli (UPEC) are amongst the most common bacterial infectious diseases in the developed world. The urovirulence of UPEC is mainly associated with the surface-exposed fimbrial adhesins and adhesins of the autotransporter (AT) family. The best studied of these proteins is antigen Ag43 mediating cell aggregation, adhesion and biofilm development as the causes of chronic UTIs. The E. coli IH11128 Dr(+) (dra (+)) strain of the Dr/Afa(+) family of adhesins possesses two major surface-exposed virulence factors: Dr fimbrial polyadhesin and DraD protein (fimbrial tip subunit or protein component of the adhesive sheath). Here, we identified for the first time, to our knowledge, the agn43 gene encoding Ag43 in the WT clinical isolate of UPEC Dr(+) as a new virulence factor not yet tested. We also found that Dr fimbrial expression, which like Ag43 is under the control of a phase-variable mechanism, did not exclude Ag43 surface presentation. However, the presence of Dr fimbriae supported by other structures on the cell surface caused a physical neutralization of Ag43-mediated autoaggregation during in vitro growth. The fimbrial bundling further increased the distance between the adjacent Ag43(+) cells, thus preventing head-to-tail association between surface-exposed Ag43 subunits and their interactions with the host cells. The investigations showed that Ag43 did not act as a specific adhesin and invasin, conversely to the major virulence factors of E. coli Dr(+), but played significant roles in the viability and metabolic activity of bacterial cells forming biofilm, and in the survival of bacteria within invaded epithelial cells.

  2. Protein-based profiling of the immune response to uropathogenic Escherichia coli in adult patients immediately following hospital admission for acute cystitis.

    PubMed

    Sundac, Lana; Dando, Samantha J; Sullivan, Matthew J; Derrington, Petra; Gerrard, John; Ulett, Glen C

    2016-08-01

    Urinary tract infections (UTIs) caused by uropathogenic Escherichia coli (UPEC) are common infections in humans. Despite the substantial healthcare cost represented by these infections, the human immune response associated with the infection immediately following the onset of symptoms in patients remains largely undefined. We performed a prospective study aimed at defining the milieu of urinary cytokines in adult inpatients in the 24-48 h period immediately following hospital admission for acute cystitis due to UPEC. Urine samples, analyzed using 27-target multiplex protein assays, were used to generate immune profiles for patients and compared to age- and gender-matched healthy controls. The levels of multiple pro-inflammatory cytokines were significantly elevated in urine as a result of infection, an observation consistent with prior findings in murine models and clinical literature. We also identified significant responses for several novel factors not previously associated with the human response to UTI, including Interleukin (IL)-4, IL-7, IL-9, IL-17A, eotaxin, Granulocyte-macrophage colony-stimulating factor (GM-CSF) and several growth factors. These data establish crucial parallels between the human immune response to UPEC and murine model UTI studies, and emphasize the complex but poorly defined nature of the human immune response to UPEC, particularly in the immediate period following the onset of symptoms for acute cystitis. PMID:27354295

  3. Phenotypic Heterogeneity in Expression of the K1 Polysaccharide Capsule of Uropathogenic Escherichia coli and Downregulation of the Capsule Genes during Growth in Urine.

    PubMed

    King, Jane E; Aal Owaif, Hasan A; Jia, Jia; Roberts, Ian S

    2015-07-01

    Uropathogenic Escherichia coli (UPEC) is the major causative agent of uncomplicated urinary tract infections (UTI). The K1 capsule on the surface of UPEC strains is a key virulence factor, and its expression may be important in the onset and progression of UTI. In order to understand capsule expression in more detail, we analyzed its expression in the UPEC strain UTI89 during growth in rich medium (LB medium) and urine and during infection of a bladder epithelial cell line. Comparison of capsule gene transcription using a chromosomal gfp reporter fusion showed a significant reduction in transcription during growth in urine compared to that during growth in LB medium. When examined at the single-cell level, following growth in both media, capsule gene expression appears to be heterogeneous, with two distinct green fluorescent protein (GFP)-expressing populations. Using anti-K1 antibody, we showed that this heterogeneity in gene expression results in two populations of encapsulated and unencapsulated cells. We demonstrated that the capsule hinders attachment to and invasion of epithelial cells and that the unencapsulated cells within the population preferentially adhere to and invade bladder epithelial cells. We found that once internalized, UTI89 starts to produce capsule to aid in its intracellular survival and spread. We propose that this observed phenotypic diversity in capsule expression is a fitness strategy used by the bacterium to deal with the constantly changing environment of the urinary tract.

  4. Phenotypic Heterogeneity in Expression of the K1 Polysaccharide Capsule of Uropathogenic Escherichia coli and Downregulation of the Capsule Genes during Growth in Urine

    PubMed Central

    King, Jane E.; Aal Owaif, Hasan A.; Jia, Jia

    2015-01-01

    Uropathogenic Escherichia coli (UPEC) is the major causative agent of uncomplicated urinary tract infections (UTI). The K1 capsule on the surface of UPEC strains is a key virulence factor, and its expression may be important in the onset and progression of UTI. In order to understand capsule expression in more detail, we analyzed its expression in the UPEC strain UTI89 during growth in rich medium (LB medium) and urine and during infection of a bladder epithelial cell line. Comparison of capsule gene transcription using a chromosomal gfp reporter fusion showed a significant reduction in transcription during growth in urine compared to that during growth in LB medium. When examined at the single-cell level, following growth in both media, capsule gene expression appears to be heterogeneous, with two distinct green fluorescent protein (GFP)-expressing populations. Using anti-K1 antibody, we showed that this heterogeneity in gene expression results in two populations of encapsulated and unencapsulated cells. We demonstrated that the capsule hinders attachment to and invasion of epithelial cells and that the unencapsulated cells within the population preferentially adhere to and invade bladder epithelial cells. We found that once internalized, UTI89 starts to produce capsule to aid in its intracellular survival and spread. We propose that this observed phenotypic diversity in capsule expression is a fitness strategy used by the bacterium to deal with the constantly changing environment of the urinary tract. PMID:25870229

  5. Inhibitors of TonB Function Identified by a High-Throughput Screen for Inhibitors of Iron Acquisition in Uropathogenic Escherichia coli CFT073

    PubMed Central

    Yep, Alejandra; McQuade, Thomas; Kirchhoff, Paul; Larsen, Martha; Mobley, Harry L. T.

    2014-01-01

    ABSTRACT The urinary tract is one of the most common sites of infection in humans, and uropathogenic Escherichia coli (UPEC) is the main causative agent of urinary tract infections. Bacteria colonizing the urinary tract face extremely low iron availability. To counteract this, UPEC expresses a wide variety of iron acquisition systems. To exploit iron acquisition in UPEC as a global target for small-molecule inhibition, we developed and carried out a whole-cell growth-based high throughput screen of 149,243 compounds. Our primary assay was carried out under iron-limiting conditions. Hits in the primary screen were assayed using two counterscreens that ruled out iron chelators and compounds that inhibit growth by means other than inhibition of iron acquisition. We determined dose-response curves under two different iron conditions and purchased fresh compounds for selected hits. After retesting dose-response relationships, we identified 16 compounds that arrest growth of UPEC only under iron-limiting conditions. All compounds are bacteriostatic and do not inhibit proton motive force. A loss-of-target strategy was employed to identify the cellular target of these inhibitors. Two compounds lost inhibitory activity against a strain lacking TonB and were shown to inhibit irreversible adsorption of a TonB-dependent bacteriophage. Our results validate iron acquisition as a target for antibacterial strategies against UPEC and identify TonB as one of the cellular targets. PMID:24570372

  6. Anti-Adhesive Activity of Cranberry Phenolic Compounds and Their Microbial-Derived Metabolites against Uropathogenic Escherichia coli in Bladder Epithelial Cell Cultures.

    PubMed

    de Llano, Dolores González; Esteban-Fernández, Adelaida; Sánchez-Patán, Fernando; Martínlvarez, Pedro J; Moreno-Arribas, Maria Victoria; Bartolomé, Begoña

    2015-01-01

    Cranberry consumption has shown prophylactic effects against urinary tract infections (UTI), although the mechanisms involved are not completely understood. In this paper, cranberry phenolic compounds and their potential microbial-derived metabolites (such as simple phenols and benzoic, phenylacetic and phenylpropionic acids) were tested for their capacity to inhibit the adherence of uropathogenic Escherichia coli (UPEC) ATCC®53503™ to T24 epithelial bladder cells. Catechol, benzoic acid, vanillic acid, phenylacetic acid and 3,4-dihydroxyphenylacetic acid showed anti-adhesive activity against UPEC in a concentration-dependent manner from 100-500 µM, whereas procyanidin A2, widely reported as an inhibitor of UPEC adherence on uroepithelium, was only statistically significant (p < 0.05) at 500 µM (51.3% inhibition). The results proved for the first time the anti-adhesive activity of some cranberry-derived phenolic metabolites against UPEC in vitro, suggesting that their presence in the urine could reduce bacterial colonization and progression of UTI. PMID:26023719

  7. Protein-based profiling of the immune response to uropathogenic Escherichia coli in adult patients immediately following hospital admission for acute cystitis.

    PubMed

    Sundac, Lana; Dando, Samantha J; Sullivan, Matthew J; Derrington, Petra; Gerrard, John; Ulett, Glen C

    2016-08-01

    Urinary tract infections (UTIs) caused by uropathogenic Escherichia coli (UPEC) are common infections in humans. Despite the substantial healthcare cost represented by these infections, the human immune response associated with the infection immediately following the onset of symptoms in patients remains largely undefined. We performed a prospective study aimed at defining the milieu of urinary cytokines in adult inpatients in the 24-48 h period immediately following hospital admission for acute cystitis due to UPEC. Urine samples, analyzed using 27-target multiplex protein assays, were used to generate immune profiles for patients and compared to age- and gender-matched healthy controls. The levels of multiple pro-inflammatory cytokines were significantly elevated in urine as a result of infection, an observation consistent with prior findings in murine models and clinical literature. We also identified significant responses for several novel factors not previously associated with the human response to UTI, including Interleukin (IL)-4, IL-7, IL-9, IL-17A, eotaxin, Granulocyte-macrophage colony-stimulating factor (GM-CSF) and several growth factors. These data establish crucial parallels between the human immune response to UPEC and murine model UTI studies, and emphasize the complex but poorly defined nature of the human immune response to UPEC, particularly in the immediate period following the onset of symptoms for acute cystitis.

  8. Distribution of virulence genes and multiple drug-resistant patterns amongst different phylogenetic groups of uropathogenic Escherichia coli isolated from patients with urinary tract infection.

    PubMed

    Derakhshandeh, A; Firouzi, R; Motamedifar, M; Motamedi Boroojeni, A; Bahadori, M; Arabshahi, S; Novinrooz, A; Heidari, S

    2015-02-01

    A total of 85 Uropathogenic Escherichia coli (UPEC) isolates were screened against ceftiofur, oxacillin, nitrofurantoin and lincospectin using Kirby-Bauer disc diffusion method, following CLSI guidelines. Prevalence of virulent factor genes amongst the isolates was determined by PCR, using gene-specific primers against the different virulent factors. Statistical analysis of the data was performed using SPSS software. The prevalence of traT, ompT, Iss, malX and ibeA genes was 47.1%, 38.8%, 20%, 16.5% and 9.4%, respectively. The most prevalent gene in group A and D was traT, whilst in group B2 was Iss. The highest resistance has been shown against oxacillin (98.8%), followed by ceftiofur (77.6%), whilst resistance to lincospectin (2.4%) and nitrofurantoin (12.9%) had the lowest frequencies. Multidrug resistance was shown in 82.35% of the isolates, whilst this study recommend lincospectin and nitrofurantoin as choice drugs for treatment, but more investigation of the bacterial pathogenicity associated with urinary tract infection (UTI) may contribute to a better medical intervention.

  9. Intranasal immunization with fusion protein MrpH·FimH and MPL adjuvant confers protection against urinary tract infections caused by uropathogenic Escherichia coli and Proteus mirabilis.

    PubMed

    Habibi, Mehri; Asadi Karam, Mohammad Reza; Shokrgozar, Mohammad Ali; Oloomi, Mana; Jafari, Anis; Bouzari, Saeid

    2015-04-01

    Urinary tract infections (UTIs) caused by Uropathogenic Escherichia coli (UPEC) and Proteus mirabilis are among the most common infections in the world. Currently there are no vaccines available to confer protection against UTI in humans. In this study, the immune responses and protection of FimH of UPEC with MrpH antigen of P. mirabilis in different vaccine formulations with and without MPL adjuvant were assessed. Mice intranasally immunized with the novel fusion protein MrpH·FimH induced a significant increase in IgG and IgA in serum, nasal wash, vaginal wash, and urine samples. Mice immunized with fusion MrpH·FimH also showed a significant boost in cellular immunity. Addition of MPL as the adjuvant enhanced FimH and MrpH specific humoral and cellular responses in both systemic and mucosal samples. Vaccination with MrpH·FimH alone or in combination with MPL showed the highest efficiency in clearing bladder and kidney infections in mice challenged with UPEC and P. mirabilis. These findings may indicate that the protection observed correlates with the systemic, mucosal and cellular immune responses induced by vaccination with these preparations. Our data suggest MrpH·FimH fusion protein with or without MPL as adjuvant could be potential vaccine candidates for elimination of UPEC and P. mirabilis. These data altogether are promising and these formulations are good candidates for elimination of UPEC and P. mirabilis.

  10. Toll-like Receptors 4 and 5 Cooperatively Initiate the Innate Immune Responses to Uropathogenic Escherichia coli Infection in Mouse Epididymal Epithelial Cells.

    PubMed

    Cheng, Lijing; Chen, Qiaoyuan; Zhu, Weiwei; Wu, Han; Wang, Qing; Shi, Lili; Zhao, Xiang; Han, Daishu

    2016-03-01

    Uropathogenic Escherichia coli (UPEC) may cause epididymitis and impair male fertility. The mechanisms underlying the innate immune responses to UPEC infection in the epididymis are not fully understood. This study showed that UPEC induced innate immune responses in mouse epididymal epithelial cells (EECs) through the activation of Toll-like receptor 4 (TLR4) and TLR5. Infection with UPEC significantly induced the expression of proinflammatory cytokines, including tumor necrosis factor alpha, interleukin 6, and monocyte chemoattractant protein 1, in EECs through the activation of nuclear factor kappa B. Moreover, UPEC induced the production of type 1 interferons by EECs through the activation of interferon regulatory factor 3. The UPEC-induced innate immune responses were significantly reduced in the EECs of Tlr4 or Tlr5 knockout mice. The innate immune responses were further reduced in Tlr4 and Tlr5 double-knockout EECs. Furthermore, we demonstrated that TLR4 and TLR5 cooperatively initiated the epididymal innate immune responses to UPEC infection in vivo. The results provide novel insights into the mechanisms underlying the epididymal innate immune responses to UPEC infection.

  11. Use of flagellin and cholera toxin as adjuvants in intranasal vaccination of mice to enhance protective immune responses against uropathogenic Escherichia coli antigens.

    PubMed

    Asadi Karam, Mohammad Reza; Habibi, Mehri; Bouzari, Saeid

    2016-09-01

    Urinary tract infections (UTIs) caused by Uropathogenic Escherichia coli (UPEC) are among the most common infections in human. Antibiotics are common therapy for UTIs, but increase in antibiotic resistance will complicate future treatment of the infections, making the development of an efficacious UTI vaccine more urgent. In this study, we have evaluated intranasally the efficacy of FliC and FimH antigens of UPEC in different vaccine formulations with and without cholera toxin (CT) adjuvant. Immunization of mice with FliC in fusion form or admixed with FimH elicited higher levels of serum, mucosal and cell-mediated responses than FimH alone. Furthermore, the use of CT in synergism with FliC resulted in the stimulation of a mixed Th1 and Th2 responses against FimH and FliC as antigen and maintained the antibody responses for at least 24 weeks following the last vaccine dose. Of the vaccine preparations, Fusion, Fusion + CT, and FimH admixed with FliC and CT showed the best protection against UPEC. These data indicated that intranasal administration of a FliC and CT adjuvant-based vaccine has the potential to provide protective responses against UPEC strains.

  12. Antimicrobial resistance and distribution of sul genes and integron-associated intI genes among uropathogenic Escherichia coli in Queensland, Australia.

    PubMed

    Gündoğdu, Aycan; Long, Ysanne Beverley; Vollmerhausen, Tara Leigh; Katouli, Mohammad

    2011-11-01

    We studied 137 uropathogenic Escherichia coli (UPEC) isolates from hospitalized adult patients (Queensland, Australia) for their resistance to 17 antimicrobial agents using the calibrated dichotomous sensitivity method and the presence of class I, II and III integron-associated integrase (intI) genes, including functional class II intI2, as well as the presence of sul1, sul2 and sul3 genes, using PCR. Randomly amplified polymorphic DNA PCR, a high-resolution biochemical-fingerprinting method (PhP) and phylogenetic grouping were also used to identify the clonality of the sulphonamide-resistant isolates. One hundred and twenty (87.6 %) isolates were resistant to one or more of the tested antimicrobial drugs, with the highest resistance (70.1 %) observed against sulphafurazole (96 isolates). Of these, 84 (87.5 %) contained one or more sul alleles, with sul1 being the most common allele [occurring in 69 (72 %) isolates]. Only 38 of 69 (55.1 %) strains carrying the sul1 gene were positive for class I integrase. Our results indicate a high prevalence of sulphafurazole-resistant UPEC strains belonging to different clones among patients with urinary tract infection in Queensland, Australia. We also conclude that these strains carry predominantly a sul1 gene that is not commonly associated with the presence of class I integrase, indicating that it may be carried on either a bacterial chromosome or other genetic elements.

  13. Antimicrobial resistance genes in marine bacteria and human uropathogenic Escherichia coli from a region of intensive aquaculture.

    PubMed

    Tomova, Alexandra; Ivanova, Larisa; Buschmann, Alejandro H; Rioseco, Maria Luisa; Kalsi, Rajinder K; Godfrey, Henry P; Cabello, Felipe C

    2015-10-01

    Antimicrobials are heavily used in Chilean salmon aquaculture. We previously found significant differences in antimicrobial-resistant bacteria between sediments from an aquaculture and a non-aquaculture site. We now show that levels of antimicrobial resistance genes (ARG) are significantly higher in antimicrobial-selected marine bacteria than in unselected bacteria from these sites. While ARG in tetracycline- and florfenicol-selected bacteria from aquaculture and non-aquaculture sites were equally frequent, there were significantly more plasmid-mediated quinolone resistance genes per bacterium and significantly higher numbers of qnrB genes in quinolone-selected bacteria from the aquaculture site. Quinolone-resistant urinary Escherichia coli from patients in the Chilean aquacultural region were significantly enriched for qnrB (including a novel qnrB gene), qnrS, qnrA and aac(6')-1b, compared with isolates from New York City. Sequences of qnrA1, qnrB1 and qnrS1 in quinolone-resistant Chilean E. coli and Chilean marine bacteria were identical, suggesting horizontal gene transfer between antimicrobial-resistant marine bacteria and human pathogens. PMID:26259681

  14. Antimicrobial resistance genes in marine bacteria and human uropathogenic Escherichia coli from a region of intensive aquaculture.

    PubMed

    Tomova, Alexandra; Ivanova, Larisa; Buschmann, Alejandro H; Rioseco, Maria Luisa; Kalsi, Rajinder K; Godfrey, Henry P; Cabello, Felipe C

    2015-10-01

    Antimicrobials are heavily used in Chilean salmon aquaculture. We previously found significant differences in antimicrobial-resistant bacteria between sediments from an aquaculture and a non-aquaculture site. We now show that levels of antimicrobial resistance genes (ARG) are significantly higher in antimicrobial-selected marine bacteria than in unselected bacteria from these sites. While ARG in tetracycline- and florfenicol-selected bacteria from aquaculture and non-aquaculture sites were equally frequent, there were significantly more plasmid-mediated quinolone resistance genes per bacterium and significantly higher numbers of qnrB genes in quinolone-selected bacteria from the aquaculture site. Quinolone-resistant urinary Escherichia coli from patients in the Chilean aquacultural region were significantly enriched for qnrB (including a novel qnrB gene), qnrS, qnrA and aac(6')-1b, compared with isolates from New York City. Sequences of qnrA1, qnrB1 and qnrS1 in quinolone-resistant Chilean E. coli and Chilean marine bacteria were identical, suggesting horizontal gene transfer between antimicrobial-resistant marine bacteria and human pathogens.

  15. Inactivation of Uropathogenic Escherichia coli in Ground Chicken Meat Using High Pressure Processing and Gamma Radiation, and in Purge and Chicken Meat Surfaces by Ultraviolet Light.

    PubMed

    Sommers, Christopher H; Scullen, O J; Sheen, Shiowshuh

    2016-01-01

    Extraintestinal pathogenic Escherichia coli, including uropathogenic E. coli (UPEC), are common contaminants in poultry meat and may cause urinary tract infections after colonization of the gastrointestinal tract and transfer of contaminated feces to the urethra. Three non-thermal processing technologies used to improve the safety and shelf-life of both human and pet foods include high pressure processing (HPP), ionizing (gamma) radiation (GR), and ultraviolet light (UV-C). Multi-isolate cocktails of UPEC were inoculated into ground chicken which was then treated with HPP (4°C, 0-25 min) at 300, 400, or 500 MPa. HPP D10, the processing conditions needed to inactivate 1 log of UPEC, was 30.6, 8.37, and 4.43 min at 300, 400, and 500 MPa, respectively. When the UPEC was inoculated into ground chicken and gamma irradiated (4 and -20°C) the GR D10 were 0.28 and 0.36 kGy, respectively. The UV-C D10 of UPEC in chicken suspended in exudate and placed on stainless steel and plastic food contact surfaces ranged from 11.4 to 12.9 mJ/cm(2). UV-C inactivated ca. 0.6 log of UPEC on chicken breast meat. These results indicate that existing non-thermal processing technologies such as HPP, GR, and UV-C can significantly reduce UPEC levels in poultry meat or exudate and provide safer poultry products for at-risk consumers. PMID:27148167

  16. Inactivation of Uropathogenic Escherichia coli in Ground Chicken Meat Using High Pressure Processing and Gamma Radiation, and in Purge and Chicken Meat Surfaces by Ultraviolet Light.

    PubMed

    Sommers, Christopher H; Scullen, O J; Sheen, Shiowshuh

    2016-01-01

    Extraintestinal pathogenic Escherichia coli, including uropathogenic E. coli (UPEC), are common contaminants in poultry meat and may cause urinary tract infections after colonization of the gastrointestinal tract and transfer of contaminated feces to the urethra. Three non-thermal processing technologies used to improve the safety and shelf-life of both human and pet foods include high pressure processing (HPP), ionizing (gamma) radiation (GR), and ultraviolet light (UV-C). Multi-isolate cocktails of UPEC were inoculated into ground chicken which was then treated with HPP (4°C, 0-25 min) at 300, 400, or 500 MPa. HPP D10, the processing conditions needed to inactivate 1 log of UPEC, was 30.6, 8.37, and 4.43 min at 300, 400, and 500 MPa, respectively. When the UPEC was inoculated into ground chicken and gamma irradiated (4 and -20°C) the GR D10 were 0.28 and 0.36 kGy, respectively. The UV-C D10 of UPEC in chicken suspended in exudate and placed on stainless steel and plastic food contact surfaces ranged from 11.4 to 12.9 mJ/cm(2). UV-C inactivated ca. 0.6 log of UPEC on chicken breast meat. These results indicate that existing non-thermal processing technologies such as HPP, GR, and UV-C can significantly reduce UPEC levels in poultry meat or exudate and provide safer poultry products for at-risk consumers.

  17. Inactivation of Uropathogenic Escherichia coli in Ground Chicken Meat Using High Pressure Processing and Gamma Radiation, and in Purge and Chicken Meat Surfaces by Ultraviolet Light

    PubMed Central

    Sommers, Christopher H.; Scullen, O. J.; Sheen, Shiowshuh

    2016-01-01

    Extraintestinal pathogenic Escherichia coli, including uropathogenic E. coli (UPEC), are common contaminants in poultry meat and may cause urinary tract infections after colonization of the gastrointestinal tract and transfer of contaminated feces to the urethra. Three non-thermal processing technologies used to improve the safety and shelf-life of both human and pet foods include high pressure processing (HPP), ionizing (gamma) radiation (GR), and ultraviolet light (UV-C). Multi-isolate cocktails of UPEC were inoculated into ground chicken which was then treated with HPP (4°C, 0–25 min) at 300, 400, or 500 MPa. HPP D10, the processing conditions needed to inactivate 1 log of UPEC, was 30.6, 8.37, and 4.43 min at 300, 400, and 500 MPa, respectively. When the UPEC was inoculated into ground chicken and gamma irradiated (4 and -20°C) the GR D10 were 0.28 and 0.36 kGy, respectively. The UV-C D10 of UPEC in chicken suspended in exudate and placed on stainless steel and plastic food contact surfaces ranged from 11.4 to 12.9 mJ/cm2. UV-C inactivated ca. 0.6 log of UPEC on chicken breast meat. These results indicate that existing non-thermal processing technologies such as HPP, GR, and UV-C can significantly reduce UPEC levels in poultry meat or exudate and provide safer poultry products for at-risk consumers. PMID:27148167

  18. Distribution and degree of heterogeneity of the afimbrial-adhesin-encoding operon (afa) among uropathogenic Escherichia coli isolates.

    PubMed

    Labigne-Roussel, A; Falkow, S

    1988-03-01

    The afimbrial adhesin (AFA-I) from a pyelonephritic Escherichia coli isolate (KS52) is a mannose-resistant, P-independent, X-binding adhesin, expressed by the afa-1 operon. It is distinct from the E. coli X-binding adhesins with M and S specificity. A total of 138 E. coli isolates belonging to various serotypes, mostly from urinary tract infections, were screened for the presence of DNA sequences related to the afa operon and for the expression of an X-adhesin able to mediate mannose-resistant hemagglutination (MRHA) and adhesion to uroepithelial cells. Fifteen strains were shown to harbor DNA sequences related to the AFA-I-encoding operon, and 13 of them expressed an X-adhesin. Using as probes different DNA segments of the AFA-I-encoding operon in Southern experiments, we demonstrated that only three of these clinical isolates contained genetic determinants closely related to those identified in the original afa prototype strain (KS52): presence of the afaA, afaB, afaC, afaD, and afaE genes associated with the expression of a 16,000-dalton hemagglutinin-adhesin which strongly cross-reacted with AFA-I-specific antibodies. The other E. coli isolates harbored DNA sequences homologous to the afaA, afaB, afaC, and afaD genes, but lacked the sequence corresponding to the adhesin-producing gene afaE; Western blots allowed the detection of polypeptides (15,000, 15,500, or 16,000 daltons) in these strains which cross-reacted with variable intensity with antibodies raised against the denatured AFA-I protein, but did not cross-react with native AFA-I-specific antibodies. Following DNA cloning experiments from chromosomal DNA of two of those strains (A22 and A30), we demonstrated that although the AFA-related operon in A22 and A30 strains lacked the AFA-I adhesin-encoding gene, they synthesized a functional X-adhesin. Thus, strains A22 and A30 encode adhesins designated AFA-II and AFA-III, which were cloned on recombinant plasmids pILL72 and pILL61, respectively. Southern

  19. In silico design of fusion protein of FimH from uropathogenic Escherichia coli and MrpH from Proteus mirabilis against urinary tract infections

    PubMed Central

    Habibi, Mehri; Asadi Karam, Mohammad Reza; Bouzari, Saeid

    2015-01-01

    Background: Urinary tract infections (UTIs) caused by uropathogenic Escherichia coli (UPEC) and Proteus mirabilis are the most important pathogens causing UTIs. The FimH from type 1 pili of UPEC and the MrpH from P. mirabilis play critical roles in the UTI process and have presented as ideal vaccine candidates against UTIs. There is no effective vaccine against UTI and the development of an ideal UTI vaccine is required. Materials and Methods: In this study, we planned to design a novel fusion protein of FimH from UPEC and MrpH from P. mirabilis. For this purpose, we modeled fusion protein forms computationally using the Iterative Threading Assembly Refinement (I-TASSER) server and evaluated their interactions with toll-like receptor 4 (TLR4). The best fusion protein was constructed using overlap extension polymerase chain reaction (OE-PCR) and the biological activity of fusion was evaluated by the induction of interleukin-8 (IL-8) in the HT-29 cell line. Results: Our study indicated that based on the Protein Structure Analysis (ProSA)-web and the docking results, MrpH.FimH showed better results than did FimH.MrpH, and it was selected for construction. The results of bioassay on the HT-29 showed that FimH and MrpH.FimH induced significantly higher IL-8 responses than untreated cells or MrpH alone in the cell line tested. Conclusions: In the present study, we designed and constructed the novel fusion protein MrpH.FimH from UPEC and P. mirabilis based on in silico methods. Our bioassay results indicate that the MrpH.FimH fusion protein is active and capable of inducing immune responses. PMID:26605246

  20. Surfactant protein D inhibits adherence of uropathogenic Escherichia coli to the bladder epithelial cells and the bacterium-induced cytotoxicity: a possible function in urinary tract.

    PubMed

    Kurimura, Yuichiro; Nishitani, Chiaki; Ariki, Shigeru; Saito, Atsushi; Hasegawa, Yoshihiro; Takahashi, Motoko; Hashimoto, Jiro; Takahashi, Satoshi; Tsukamoto, Taiji; Kuroki, Yoshio

    2012-11-16

    The adherence of uropathogenic Escherichia coli (UPEC) to the host urothelial surface is the first step for establishing UPEC infection. Uroplakin Ia (UPIa), a glycoprotein expressed on bladder urothelium, serves as a receptor for FimH, a lectin located at bacterial pili, and their interaction initiates UPEC infection. Surfactant protein D (SP-D) is known to be expressed on mucosal surfaces in various tissues besides the lung. However, the functions of SP-D in the non-pulmonary tissues are poorly understood. The purposes of this study were to investigate the possible function of SP-D expressed in the bladder urothelium and the mechanisms by which SP-D functions. SP-D was expressed in human bladder mucosa, and its mRNA was increased in the bladder of the UPEC infection model in mice. SP-D directly bound to UPEC and strongly agglutinated them in a Ca(2+)-dependent manner. Co-incubation of SP-D with UPEC decreased the bacterial adherence to 5637 cells, the human bladder cell line, and the UPEC-induced cytotoxicity. In addition, preincubation of SP-D with 5637 cells resulted in the decreased adherence of UPEC to the cells and in a reduced number of cells injured by UPEC. SP-D directly bound to UPIa and competed with FimH for UPIa binding. Consistent with the in vitro data, the exogenous administration of SP-D inhibited UPEC adherence to the bladder and dampened UPEC-induced inflammation in mice. These results support the conclusion that SP-D can protect the bladder urothelium against UPEC infection and suggest a possible function of SP-D in urinary tract.

  1. Escherichia Coli

    ERIC Educational Resources Information Center

    Goodsell, David S.

    2009-01-01

    Diverse biological data may be used to create illustrations of molecules in their cellular context. I describe the scientific results that support a recent textbook illustration of an "Escherichia coli cell". The image magnifies a portion of the bacterium at one million times, showing the location and form of individual macromolecules. Results…

  2. Genomic analysis of a pathogenicity island in uropathogenic Escherichia coli CFT073: distribution of homologous sequences among isolates from patients with pyelonephritis, cystitis, and Catheter-associated bacteriuria and from fecal samples.

    PubMed

    Guyer, D M; Kao, J S; Mobley, H L

    1998-09-01

    Urinary tract infection is the most frequently diagnosed kidney and urologic disease and Escherichia coli is by far the most common etiologic agent. Uropathogenic strains have been shown to contain blocks of DNA termed pathogenicity islands (PAIs) which contribute to their virulence. We have defined one of these regions of DNA within the chromosome of a highly virulent E. coli strain, CFT073, isolated from the blood and urine of a woman with acute pyelonephritis. The 57,988-bp stretch of DNA has characteristics which define PAIs, including a size greater than 30 kb, the presence of insertion sequences, distinct segmentation of K-12 and J96 origin, GC content (42.9%) different from that of total genomic DNA (50.8%), and the presence of virulence genes (hly and pap). Within this region, we have identified 44 open reading frames; of these 44, 10 are homologous to entries in the complete K-12 genome sequence, 4 are nearly identical to the sequences of E. coli J96 encoding the HlyA hemolysin, 11 encode P fimbriae, and 19 show no homology to J96 or K-12 entries. To determine whether sequences found within the junctions of the PAI of CFT073 were common to other uropathogenic strains of E. coli, 11 probes were isolated along the length of the PAI and were hybridized to dot blots of genomic DNA isolated from clinical isolates (67 from patients with acute pyelonephritis, 38 from patients with cystitis, 49 from patients with catheter-associated bacteriuria, and 27 from fecal samples). These sequences were found significantly more often in strains associated with the clinical syndromes of acute pyelonephritis (79%) and cystitis (82%) than in those associated with catheter-associated bacteriuria (58%) and in fecal strains (22%) (P < 0.001). From these regions, we have identified a putative iron transport system and genes other than hly and pap that may contribute to the virulent phenotype of uropathogenic E. coli strains.

  3. Ameliorating Effect of Ginseng on Epididymo-Orchitis Inducing Alterations in Sperm Quality and Spermatogenic Cells Apoptosis following Infection by Uropathogenic Escherichia coli in Rats

    PubMed Central

    Eskandari, Mehdi; Jani, Soghra; Kazemi, Mahsa; Zeighami, Habib; Yazdinezhad, Alireza; Mazloomi, Sahar; Shokri, Saeed

    2016-01-01

    Objective Epididymo-orchitis (EO) potentially results in reduced fertility in up to 60% of affected patients. The anti-inflammatory effects of Korean red ginseng (KRG) and its ability to act as an immunoenhancer in parallel with the beneficial effects of this ancient herbal medicine on the reproductive systems of animals and humans led us to evaluate its protective effects against acute EO. Materials and Methods This animal experimental study was conducted in the Department of Anatomical Sciences, Faculty of Medicine, Zanjan University of Medical Sciences (ZUMS), Zanjan, Iran during 2013-2015. We divided 50 Wistar rats into five following groups (n=10 per group): i. Control-intact animals, ii. Vehicle-phosphate buffered saline (PBS) injection into the vas deferens, iii. KRG-an intraperitoneal (IP) injection of KRG, iv. EO-an injection of uropathogenic Escherichia coli (UPEC) strain M39 into the vas defer- ens, and v. EO/ KRG-injections of both UPEC strain M39 and KRG. The treatment lasted seven days. We then evaluated sperm parameters, number of germ cell layers, Johnson’s criteria, germ cell apoptosis, body weight and relative sex organs weight. Results Acute EO increased the relative weight of prostate and seminal vesicles (P≤0.05). It also reduced sperm quality such as total motility, sperm concentration (P≤0.01), and the percentage of normal sperm (P≤0.001). Moreover, acute EO decreased Miller’s (P≤0.05) and Johnsen’s scores and increased apoptotic indexes of spermatogenic cells (P≤0.001). KRG treatment decreased prostate weight gain (P≤0.05) and improved the percentage of sperm with normal morphology, total motility (P≤0.01), and progressive motility (P≤0.05). The apoptotic indexes of spermatogenic cells reduced (P≤0.001), whereas both Johnsen’s (P≤0.01) and Miller’s criteria increased in the KRG-treated EO testis (P≤0.05). Conclusion Consequently, KRG ameliorated the devastating effects of EO on the sperm retrieved from either

  4. Ameliorating Effect of Ginseng on Epididymo-Orchitis Inducing Alterations in Sperm Quality and Spermatogenic Cells Apoptosis following Infection by Uropathogenic Escherichia coli in Rats

    PubMed Central

    Eskandari, Mehdi; Jani, Soghra; Kazemi, Mahsa; Zeighami, Habib; Yazdinezhad, Alireza; Mazloomi, Sahar; Shokri, Saeed

    2016-01-01

    Objective Epididymo-orchitis (EO) potentially results in reduced fertility in up to 60% of affected patients. The anti-inflammatory effects of Korean red ginseng (KRG) and its ability to act as an immunoenhancer in parallel with the beneficial effects of this ancient herbal medicine on the reproductive systems of animals and humans led us to evaluate its protective effects against acute EO. Materials and Methods This animal experimental study was conducted in the Department of Anatomical Sciences, Faculty of Medicine, Zanjan University of Medical Sciences (ZUMS), Zanjan, Iran during 2013-2015. We divided 50 Wistar rats into five following groups (n=10 per group): i. Control-intact animals, ii. Vehicle-phosphate buffered saline (PBS) injection into the vas deferens, iii. KRG-an intraperitoneal (IP) injection of KRG, iv. EO-an injection of uropathogenic Escherichia coli (UPEC) strain M39 into the vas defer- ens, and v. EO/ KRG-injections of both UPEC strain M39 and KRG. The treatment lasted seven days. We then evaluated sperm parameters, number of germ cell layers, Johnson’s criteria, germ cell apoptosis, body weight and relative sex organs weight. Results Acute EO increased the relative weight of prostate and seminal vesicles (P≤0.05). It also reduced sperm quality such as total motility, sperm concentration (P≤0.01), and the percentage of normal sperm (P≤0.001). Moreover, acute EO decreased Miller’s (P≤0.05) and Johnsen’s scores and increased apoptotic indexes of spermatogenic cells (P≤0.001). KRG treatment decreased prostate weight gain (P≤0.05) and improved the percentage of sperm with normal morphology, total motility (P≤0.01), and progressive motility (P≤0.05). The apoptotic indexes of spermatogenic cells reduced (P≤0.001), whereas both Johnsen’s (P≤0.01) and Miller’s criteria increased in the KRG-treated EO testis (P≤0.05). Conclusion Consequently, KRG ameliorated the devastating effects of EO on the sperm retrieved from either

  5. Comparison of virulence factors and expression of specific genes between uropathogenic Escherichia coli and avian pathogenic E. coli in a murine urinary tract infection model and a chicken challenge model.

    PubMed

    Zhao, Lixiang; Gao, Song; Huan, Haixia; Xu, Xiaojing; Zhu, Xiaoping; Yang, Weixia; Gao, Qingqing; Liu, Xiufan

    2009-05-01

    Avian pathogenic Escherichia coli (APEC) and uropathogenic E. coli (UPEC) establish infections in extraintestinal habitats of different hosts. As the diversity, epidemiological sources and evolutionary origins of extraintestinal pathogenic E. coli (ExPEC) are so far only partially defined, in the present study,100 APEC isolates and 202 UPEC isolates were compared by their content of virulence genes and phylogenetic groups. The two groups showed substantial overlap in terms of their serogroups, phylogenetic groups and virulence genotypes, including their possession of certain genes associated with large transmissible plasmids of APEC. In a chicken challenge model, both UPEC U17 and APEC E058 had similar LD(50), demonstrating that UPEC U17 had the potential to cause significant disease in poultry. To gain further information about the similarities between UPEC and APEC, the in vivo expression of 152 specific genes of UPEC U17 and APEC E058 in both a murine urinary tract infection (UTI) model and a chicken challenge model was compared with that of these strains grown statically to exponential phase in rich medium. It was found that in the same model (murine UTI or chicken challenge), various genes of UPEC U17 and APEC E058 showed a similar tendency of expression. Several iron-related genes were upregulated in the UTI model and/or chicken challenge model, indicating that iron acquisition is important for E. coli to survive in blood or the urinary tract. Based on these results, the potential for APEC to act as human UPEC or as a reservoir of virulence genes for UPEC should be considered. Further, this study compared the transcriptional profile of virulence genes among APEC and UPEC in vivo.

  6. Comparison of the Anti-Adhesion Activity of Three Different Cranberry Extracts on Uropathogenic P-fimbriated Escherichia coli: a Randomized, Double-blind, Placebo Controlled, Ex Vivo, Acute Study.

    PubMed

    Howell, Amy; Souza, Dan; Roller, Marc; Fromentin, Emilie

    2015-07-01

    Research suggests that cranberry (Vaccinium macrocarpon) helps maintain urinary tract health. Bacterial adhesion to the uroepithelium is the initial step in the progression to development of a urinary tract infection. The bacterial anti-adhesion activity of cranberry proanthocyanidins (PACs) has been demonstrated in vitro. Three different cranberry extracts were developed containing a standardized level of 36 mg of PACs. This randomized, double-blind, placebo controlled, ex vivo, acute study was designed to compare the anti-adhesion activity exhibited by human urine following consumption of three different cranberry extracts on uropathogenic P-fimbriated Escherichia coli in healthy men and women. All three cranberry extracts significantly increased anti-adhesion activity in urine. from 6 to 12 hours after intake of a single dose standardized to deliver 36 mg of PACs (as measured by the BL-DMAC method), versus placebo. PMID:26411014

  7. Comparison of the Anti-Adhesion Activity of Three Different Cranberry Extracts on Uropathogenic P-fimbriated Escherichia coli: a Randomized, Double-blind, Placebo Controlled, Ex Vivo, Acute Study.

    PubMed

    Howell, Amy; Souza, Dan; Roller, Marc; Fromentin, Emilie

    2015-07-01

    Research suggests that cranberry (Vaccinium macrocarpon) helps maintain urinary tract health. Bacterial adhesion to the uroepithelium is the initial step in the progression to development of a urinary tract infection. The bacterial anti-adhesion activity of cranberry proanthocyanidins (PACs) has been demonstrated in vitro. Three different cranberry extracts were developed containing a standardized level of 36 mg of PACs. This randomized, double-blind, placebo controlled, ex vivo, acute study was designed to compare the anti-adhesion activity exhibited by human urine following consumption of three different cranberry extracts on uropathogenic P-fimbriated Escherichia coli in healthy men and women. All three cranberry extracts significantly increased anti-adhesion activity in urine. from 6 to 12 hours after intake of a single dose standardized to deliver 36 mg of PACs (as measured by the BL-DMAC method), versus placebo.

  8. S fimbriae of uropathogenic Escherichia coli bind to primary human renal proximal tubular epithelial cells but do not induce expression of intercellular adhesion molecule 1.

    PubMed Central

    Kreft, B; Placzek, M; Doehn, C; Hacker, J; Schmidt, G; Wasenauer, G; Daha, M R; van der Woude, F J; Sack, K

    1995-01-01

    We have recently reported an increase of expression of the intercellular adhesion molecule 1 by renal carcinoma cells in response to S fimbriae of Escherichia coli. Now we demonstrate that E. coli expressing S and P fimbriae strongly binds to human proximal tubular epithelial cells. However, in primary and simian virus 40-transfected renal tubular epithelial cells S fimbriae do not enhance the expression of intercellular adhesion molecule 1. PMID:7622256

  9. Plasmid-related quinolone resistance determinants in epidemic Vibrio parahaemolyticus, uropathogenic Escherichia coli, and marine bacteria from an aquaculture area in Chile.

    PubMed

    Aedo, Sandra; Ivanova, Larisa; Tomova, Alexandra; Cabello, Felipe C

    2014-08-01

    Marine bacteria from aquaculture areas with industrial use of quinolones have the potential to pass quinolone resistance genes to animal and human pathogens. The VPA0095 gene, related to the quinolone resistance determinant qnrA, from clinical isolates of epidemic Vibrio parahaemolyticus conferred reduced susceptibility to quinolone after cloning into Escherichia coli K-12 either when acting alone or synergistically with DNA gyrase mutations. In addition, a plasmid-mediated quinolone resistance gene from marine bacteria, aac(6')-Ib-cr, was identical to aac(6')-Ib-cr from urinary tract isolates of E. coli, suggesting a recent flow of this gene between these bacteria isolated from different environments. aac(6')-Ib-cr from E. coli also conferred reduced susceptibility to quinolone and kanamycin when cloned into E. coli K-12.

  10. Molecular typing of uropathogenic E. coli strains by the ERIC-PCR method

    PubMed Central

    Ardakani, Maryam Afkhami; Ranjbar, Reza

    2016-01-01

    Introduction Escherichia coli (E. coli) is the most common cause of urinary infections in hospitals. The aim of this study was to evaluate the ERIC-PCR method for molecular typing of uropathogenic E. coli strains isolated from hospitalized patients. Methods In a cross sectional study, 98 E. coli samples were collected from urine samples taken from patients admitted to Baqiyatallah Hospital from June 2014 to January 2015. The disk agar diffusion method was used to determine antibiotic sensitivity. DNA proliferation based on repetitive intergenic consensus was used to classify the E. coli strains. The products of proliferation were electrophoresed on 1.5% agarose gel, and their dendrograms were drawn. The data were analyzed by online Insillico software. Results The method used in this research proliferated numerous bands (4–17 bands), ranging from 100 to 3000 base pairs. The detected strains were classified into six clusters (E1–E6) with 70% similarity between them. Conclusion In this study, uropathogenic E. coli strains belonged to different genotypic clusters. It was found that ERIC-PCR had good differentiation power for molecular typing of uropathogenic E. coli strains isolated from the patients in the study. PMID:27280007

  11. Characterization of Multidrug Resistant Extended-Spectrum Beta-Lactamase-Producing Escherichia coli among Uropathogens of Pediatrics in North of Iran

    PubMed Central

    Rezai, Mohammad Sadegh; Salehifar, Ebrahim; Rafiei, Alireza; Rafati, Mohammadreza; Shafahi, Kheironesa

    2015-01-01

    Escherichia coli remains as one of the most important bacteria causing infections in pediatrics and producing extended-spectrum beta-lactamases (ESBLs) making them resistant to beta-lactam antibiotics. In this study we aimed to genotype ESBL-producing E. coli isolates from pediatric patients for ESBL genes and determine their association with antimicrobial resistance. One hundred of the E. coli isolates were initially considered ESBL producing based on their MIC results. These isolates were then tested by polymerase chain reaction (PCR) for the presence or absence of CTX, TEM, SHV, GES, and VEB beta-lactamase genes. About 30.5% of isolated E. coli was ESBL-producing strain. The TEM gene was the most prevalent (49%) followed by SHV (44%), CTX (28%), VEB (8%), and GES (0%) genes. The ESBL-producing E. coli isolates were susceptible to carbapenems (66%) and amikacin (58%) and showed high resistance to cefixime (99%), colistin (82%), and ciprofloxacin (76%). In conclusion, carbapenems were the most effective antibiotics against ESBl-producing E. coli in urinary tract infection in North of Iran. The most prevalent gene is the TEM-type, but the other resistant genes and their antimicrobial resistance are on the rise. PMID:26064896

  12. Correlation between uropathogenic properties of Escherichia coli from urinary tract infections and the antibody-coated bacteria test and comparison with faecal strains.

    PubMed Central

    Brooks, H. J.; Benseman, B. A.; Peck, J.; Bettelheim, K. A.

    1981-01-01

    Strains of Escherichia coli isolated from adult females with symptomatic urinary tract infection were found to possess the following properties significantly more frequently than faecal strains: (i) high K-antigen titre: (ii) haemolysin; (iii) type 1 pili; (iv) mannose-resistant haemagglutination; (v) fermentation of dulcitol and salicin; (vi) O serotype 2, 6 and 75; (vii) H serotype 1. E. coli isolated form urine specimens containing significant numbers of antibody-coated bacteria were richer in these seven properties than strains from urines without detectable antibody coated bacteria. The O and H serotypes of E. coli obtained from patients with urinary tract infection in two New Zealand cities were compared with those reported in the world literature and found to be similar. PMID:6114119

  13. Comparative proteomics of uropathogenic Escherichia coli during growth in human urine identify UCA-like (UCL) fimbriae as an adherence factor involved in biofilm formation and binding to uroepithelial cells.

    PubMed

    Wurpel, Daniël J; Totsika, Makrina; Allsopp, Luke P; Webb, Richard I; Moriel, Danilo G; Schembri, Mark A

    2016-01-10

    Uropathogenic Escherichia coli (UPEC) are the primary cause of urinary tract infection (UTI) in humans. For the successful colonisation of the human urinary tract, UPEC employ a diverse collection of secreted or surface-exposed virulence factors including toxins, iron acquisition systems and adhesins. In this study, a comparative proteomic approach was utilised to define the UPEC pan and core surface proteome following growth in pooled human urine. Identified proteins were investigated for subcellular origin, prevalence and homology to characterised virulence factors. Fourteen core surface proteins were identified, as well as eleven iron uptake receptor proteins and four distinct fimbrial types, including type 1, P, F1C/S and a previously uncharacterised fimbrial type, designated UCA-like (UCL) fimbriae in this study. These pathogenicity island (PAI)-associated fimbriae are related to UCA fimbriae of Proteus mirabilis, associated with UPEC and exclusively found in members of the E. coli B2 and D phylogroup. We further demonstrated that UCL fimbriae promote significant biofilm formation on abiotic surfaces and mediate specific attachment to exfoliated human uroepithelial cells. Combined, this study has defined the surface proteomic profiles and core surface proteome of UPEC during growth in human urine and identified a new type of fimbriae that may contribute to UTI.

  14. High prevalence of multidrug resistance and random distribution of mobile genetic elements among uropathogenic Escherichia coli (UPEC) of the four major phylogenetic groups.

    PubMed

    Rijavec, Matija; Starcic Erjavec, Marjanca; Ambrozic Avgustin, Jerneja; Reissbrodt, Rolf; Fruth, Angelika; Krizan-Hergouth, Veronika; Zgur-Bertok, Darja

    2006-08-01

    One hundred and ten UTI Escherichia coli strains, from Ljubljana, Slovenia, were analyzed for antibiotic resistances, mobile DNA elements, serotype, and phylogenetic origin. A high prevalence of drug resistance and multidrug resistance was found. Twenty-six percent of the isolates harbored a class 1 integron, while a majority of the strains (56%) harbored rep sequences characteristic of F-like plasmids. int as well as rep sequences were found to be distributed in a random manner among strains of the four major phylogenetic groups indicating that all groups have a similar tendency to acquire and maintain mobile genetic elements frequently associated with resistance determinants.

  15. Isolation of Generalized Transducing Bacteriophages for Uropathogenic Strains of Escherichia coli▿†

    PubMed Central

    Battaglioli, E. J.; Baisa, G. A.; Weeks, A. E.; Schroll, R. A.; Hryckowian, A. J.; Welch, R. A.

    2011-01-01

    The traditional genetic procedure for random or site-specific mutagenesis in Escherichia coli K-12 involves mutagenesis, isolation of mutants, and transduction of the mutation into a clean genetic background. The transduction step reduces the likelihood of complications due to secondary mutations. Though well established, this protocol is not tenable for many pathogenic E. coli strains, such as uropathogenic strain CFT073, because it is resistant to known K-12 transducing bacteriophages, such as P1. CFT073 mutants generated via a technique such as lambda Red mutagenesis may contain unknown secondary mutations. Here we describe the isolation and characterization of transducing bacteriophages for CFT073. Seventy-seven phage isolates were acquired from effluent water samples collected from a wastewater treatment plant in Madison, WI. The phages were differentiated by a host sensitivity-typing scheme with a panel of E. coli strains from the ECOR collection and clinical uropathogenic isolates. We found 49 unique phage isolates. These were then examined for their ability to transduce antibiotic resistance gene insertions at multiple loci between different mutant strains of CFT073. We identified 4 different phages capable of CFT073 generalized transduction. These phages also plaque on the model uropathogenic E. coli strains 536, UTI89, and NU14. The highest-efficiency transducing phage, ΦEB49, was further characterized by DNA sequence analysis, revealing a double-stranded genome 47,180 bp in length and showing similarity to other sequenced phages. When combined with a technique like lambda Red mutagenesis, the newly characterized transducing phages provide a significant development in the genetic tools available for the study of uropathogenic E. coli. PMID:21784916

  16. In Vivo mRNA Profiling of Uropathogenic Escherichia coli from Diverse Phylogroups Reveals Common and Group-Specific Gene Expression Profiles

    PubMed Central

    Bielecki, Piotr; Muthukumarasamy, Uthayakumar; Eckweiler, Denitsa; Bielecka, Agata; Pohl, Sarah; Schanz, Ansgar; Niemeyer, Ute; Oumeraci, Tonio; von Neuhoff, Nils; Ghigo, Jean-Marc

    2014-01-01

    ABSTRACT mRNA profiling of pathogens during the course of human infections gives detailed information on the expression levels of relevant genes that drive pathogenicity and adaptation and at the same time allows for the delineation of phylogenetic relatedness of pathogens that cause specific diseases. In this study, we used mRNA sequencing to acquire information on the expression of Escherichia coli pathogenicity genes during urinary tract infections (UTI) in humans and to assign the UTI-associated E. coli isolates to different phylogenetic groups. Whereas the in vivo gene expression profiles of the majority of genes were conserved among 21 E. coli strains in the urine of elderly patients suffering from an acute UTI, the specific gene expression profiles of the flexible genomes was diverse and reflected phylogenetic relationships. Furthermore, genes transcribed in vivo relative to laboratory media included well-described virulence factors, small regulatory RNAs, as well as genes not previously linked to bacterial virulence. Knowledge on relevant transcriptional responses that drive pathogenicity and adaptation of isolates to the human host might lead to the introduction of a virulence typing strategy into clinical microbiology, potentially facilitating management and prevention of the disease. PMID:25096872

  17. [Distribution of phylogenetic groups and virulence factors in CTX-M-15 β-lactamase-producing uropathogenic Escherichia coli strains isolated from patients in the community of Mérida, Venezuela].

    PubMed

    Millán, Ysheth; Hernández, Erick; Millán, Beatriz; Araque, María

    2014-01-01

    In this study, the distribution of phylogenetic groups and the genetic detection of virulence factors in CTX-M-15 β-lactamase-producing uropathogenic Escherichia coli (UPEC) strains were analyzed. Twenty eight strains were isolated between January 2009 and July 2011 from patients with urinary tract infection (UTI) who attended the Public Health Laboratory at Mérida, Venezuela. Determination of phylogenetic groups and detection of six virulence genes, fimH, fyuA, kpsMTII, usp, PAI and papAH, were performed by PCR amplification. Fifteen of the 28 isolates were mainly located in the phylogenetic group A, followed by B2 (12/28) and D (1/28). No direct relationship between the severity or recurrence of UTI and the distribution of phylogroups was observed. All studied virulence factors were found in group B2 strains with the highest frequency. The prevalent virulence profile included the combination of three main genes: fimH, kpsMTII and fyuA and, to a lesser extent, the presence of other determinants such as usp, PAI and/or papAH. These results indicate that virulent UPEC incorporated three important properties: adhesion, iron uptake and evasion of phagocytosis, which favored the production of recurrent UTI. This is the first report describing the association of phylogenetic groups with the potential virulence of CTX-M-15 β-lactamase producing UPEC strains in Venezuela.

  18. In-vitro and in-vivo evidence of dose-dependent decrease of uropathogenic Escherichia coli virulence after consumption of commercial Vaccinium macrocarpon (cranberry) capsules.

    PubMed

    Lavigne, J-P; Bourg, G; Combescure, C; Botto, H; Sotto, A

    2008-04-01

    This study evaluated the antibacterial efficacy of the consumption of cranberry capsules vs. placebo in the urine of healthy volunteers. A first double-blind, randomised, crossover trial involved eight volunteers who had followed three regimens, with or without cranberry, with a wash-out period of at least 6 days between each regimen. Twelve hours after consumption of cranberry or placebo hard capsules, the first urine of the morning was collected. Different Escherichia coli strains were cultured in the urine samples. Urinary antibacterial adhesion activity was measured in vitro using the human T24 epithelial cell-line, and in vivo using the Caenorhabditis elegans killing model. With the in-vitro model, 108 mg of cranberry induced a significant reduction in bacterial adherence to T24 cells as compared with placebo (p <0.001). A significant dose-dependent decrease in bacterial adherence in vitro was noted after the consumption of 108 and 36 mg of cranberry (p <0.001). The in-vivo model confirmed that E. coli strains had a reduced ability to kill C. elegans after growth in the urine of patients who consumed cranberry capsules. Overall, these in-vivo and in-vitro studies suggested that consumption of cranberry juice represents an interesting new strategy to prevent recurrent urinary tract infection.

  19. A Conserved PapB Family Member, TosR, Regulates Expression of the Uropathogenic Escherichia coli RTX Nonfimbrial Adhesin TosA while Conserved LuxR Family Members TosE and TosF Suppress Motility

    PubMed Central

    Engstrom, Michael D.; Alteri, Christopher J.

    2014-01-01

    A heterogeneous subset of extraintestinal pathogenic Escherichia coli (ExPEC) strains, referred to as uropathogenic E. coli (UPEC), causes most uncomplicated urinary tract infections. However, no core set of virulence factors exists among UPEC strains. Instead, the focus of the analysis of urovirulence has shifted to studying broad classes of virulence factors and the interactions between them. For example, the RTX nonfimbrial adhesin TosA mediates adherence to host cells derived from the upper urinary tract. The associated tos operon is well expressed in vivo but poorly expressed in vitro and encodes TosCBD, a predicted type 1 secretion system. TosR and TosEF are PapB and LuxR family transcription factors, respectively; however, no role has been assigned to these potential regulators. Thus, the focus of this study was to determine how TosR and TosEF regulate tosA and affect the reciprocal expression of adhesins and flagella. Among a collection of sequenced UPEC strains, 32% (101/317) were found to encode TosA, and nearly all strains (91% [92/101]) simultaneously carried the putative regulatory genes. Deletion of tosR alleviates tosA repression. The tos promoter was localized upstream of tosR using transcriptional fusions of putative promoter regions with lacZ. TosR binds to this region, affecting a gel shift. A 100-bp fragment 220 to 319 bp upstream of tosR inhibits binding, suggesting localization of the TosR binding site. TosEF, on the other hand, downmodulate motility when overexpressed by preventing the expression of fliC, encoding flagellin. Deletion of tosEF increased motility. Thus, we present an additional example of the reciprocal control of adherence and motility. PMID:24935980

  20. Multiresistant Uropathogenic Escherichia coli from a Region in India Where Urinary Tract Infections Are Endemic: Genotypic and Phenotypic Characteristics of Sequence Type 131 Isolates of the CTX-M-15 Extended-Spectrum-β-Lactamase-Producing Lineage

    PubMed Central

    Hussain, Arif; Ewers, Christa; Nandanwar, Nishant; Guenther, Sebastian; Jadhav, Savita; Wieler, Lothar H.

    2012-01-01

    Escherichia coli sequence type 131 (O25b:H4), associated with the CTX-M-15 extended-spectrum beta-lactamases (ESBLs) and linked predominantly to the community-onset antimicrobial-resistant infections, has globally emerged as a public health concern. However, scant attention is given to the understanding of the molecular epidemiology of these strains in high-burden countries such as India. Of the 100 clinical E. coli isolates obtained by us from a setting where urinary tract infections are endemic, 16 ST131 E. coli isolates were identified by multilocus sequence typing (MLST). Further, genotyping and phenotyping methods were employed to characterize their virulence and drug resistance patterns. All the 16 ST131 isolates harbored the CTX-M-15 gene, and half of them also carried TEM-1; 11 of these were positive for blaOXA groups 1 and 12 for aac(6′)-Ib-cr. At least 12 isolates were refractory to four non-beta-lactam antibiotics: ciprofloxacin, gentamicin, sulfamethoxazole-trimethoprim, and tetracycline. Nine isolates carried the class 1 integron. Plasmid analysis indicated a large pool of up to six plasmids per strain with a mean of approximately three plasmids. Conjugation and PCR-based replicon typing (PBRT) revealed that the spread of resistance was associated with the FIA incompatibility group of plasmids. Pulsed-field gel electrophoresis (PFGE) and genotyping of the virulence genes showed a low level of diversity among these strains. The association of ESBL-encoding plasmid with virulence was demonstrated in transconjugants by serum assay. None of the 16 ST131 ESBL-producing E. coli strains were known to synthesize carbapenemase enzymes. In conclusion, our study reports a snapshot of the highly virulent/multiresistant clone ST131 of uropathogenic E. coli from India. This study suggests that the ST131 genotypes from this region are clonally evolved and are strongly associated with the CTX-M-15 enzyme, carry a high antibiotic resistance background, and have

  1. Clonal differentiation of uropathogenic Escherichia coli isolates of serotype O6:K5 by fimbrial antigen typing and DNA long-range mapping techniques.

    PubMed

    Zingler, G; Blum, G; Falkenhagen, U; Orskov, I; Orskov, F; Hacker, J; Ott, M

    1993-03-01

    Escherichia coli isolates of serotype O6:K5 are the most common causative agents of cystitis and pyelonephritis in adults. To answer the question, as to whether strains of this particular serotype represent one special clonal group, out of a collection of 34 serotype O6:K5 isolates [Zingler et al. (1990) Zentralbl. Bakteriol Mikrobiol Hyg [A] 274:372-381] 15 strains were selected and analyzed in detail. The flagellar (H) antigen and the outer membrane protein (OMP) pattern were determined. Further serum resistance properties and the genetic presence and expression of other virulence factors, including hemolysin, aerobactin, P fimbriae, S/F1C fimbriae and type 1 fimbriae was evaluated. In addition the XbaI-macrorestriction pattern of ten representative isolates was elaborated and the fimbrial (F) antigen type of the P fimbriae was determined, to obtain the complete O:K:H:F pattern. These analyses could clearly show that the O6:K5 isolates do not represent one clonal group. The XbaI-macrorestriction profiles were heterogeneous and marked differences in the hybridization patterns, using virulence-associated gene probes in Southern hybridization of long-range-separated genomic DNA, were observed among the strains. However, some of strains showed similarities in the genomic profiles, arguing for clonal groupings among the O6:K5 isolates. Interestingly the strains grouped together exhibited the same fimbrial F type that many indicate a coincidence of this phenotypic trait with clonality.

  2. In Vivo Consumption of Cranberry Exerts ex Vivo Antiadhesive Activity against FimH-Dominated Uropathogenic Escherichia coli: A Combined in Vivo, ex Vivo, and in Vitro Study of an Extract from Vaccinium macrocarpon.

    PubMed

    Rafsanjany, Nasli; Senker, Jandirk; Brandt, Simone; Dobrindt, Ulrich; Hensel, Andreas

    2015-10-14

    For investigation of the molecular interaction of cranberry extract with adhesins of uropathogenic Escherichia coli (UPEC), urine from four volunteers consuming standardized cranberry extract (proanthocyanidin content = 1.24%) was analyzed within ex vivo experiments, indicating time-dependent significant inhibition of 40-50% of bacterial adhesion of UPEC strain NU14 to human T24 bladder cells. Under in vitro conditions a dose-dependent increase in bacterial adhesion was observed with proanthocyanidin-enriched cranberry Vaccinium macrocarpon extract (proanthocyanidin content = 21%). Confocal laser scanning microscopy and scanning electron microscopy proved that V.m. extract led to the formation of bacterial clusters on the outer plasma membrane of the host cells without subsequent internalization. This agglomerating activity was not observed when a PAC-depleted extract (V.m. extract(≠PAC)) was used, which showed significant inhibition of bacterial adhesion in cases where type 1 fimbriae dominated and mannose-sensitive UPEC strain NU14 was used. V.m. extract(≠PAC) had no inhibitory activity against P- and F1C-fimbriae dominated strain 2980. Quantitative gene expression analysis indicated that PAC-containing as well as PAC-depleted cranberry extracts increased the fimH expression in NU14 as part of a feedback mechanism after blocking FimH. For strain 2980 the PAC-containing extract led to up-regulation of P- and F1C-fimbriae, whereas the PAC-depleted extract had no influence on gene expression. V.m. and V.m. extract(≠PAC) did not influence biofilm and curli formation in UPEC strains NU14 and 2980. These data lead to the conclusion that also proanthocyanidin-free cranberry extracts exert antiadhesive activity by interaction with mannose-sensitive type 1 fimbriae of UPEC. PMID:26330108

  3. In Vivo Consumption of Cranberry Exerts ex Vivo Antiadhesive Activity against FimH-Dominated Uropathogenic Escherichia coli: A Combined in Vivo, ex Vivo, and in Vitro Study of an Extract from Vaccinium macrocarpon.

    PubMed

    Rafsanjany, Nasli; Senker, Jandirk; Brandt, Simone; Dobrindt, Ulrich; Hensel, Andreas

    2015-10-14

    For investigation of the molecular interaction of cranberry extract with adhesins of uropathogenic Escherichia coli (UPEC), urine from four volunteers consuming standardized cranberry extract (proanthocyanidin content = 1.24%) was analyzed within ex vivo experiments, indicating time-dependent significant inhibition of 40-50% of bacterial adhesion of UPEC strain NU14 to human T24 bladder cells. Under in vitro conditions a dose-dependent increase in bacterial adhesion was observed with proanthocyanidin-enriched cranberry Vaccinium macrocarpon extract (proanthocyanidin content = 21%). Confocal laser scanning microscopy and scanning electron microscopy proved that V.m. extract led to the formation of bacterial clusters on the outer plasma membrane of the host cells without subsequent internalization. This agglomerating activity was not observed when a PAC-depleted extract (V.m. extract(≠PAC)) was used, which showed significant inhibition of bacterial adhesion in cases where type 1 fimbriae dominated and mannose-sensitive UPEC strain NU14 was used. V.m. extract(≠PAC) had no inhibitory activity against P- and F1C-fimbriae dominated strain 2980. Quantitative gene expression analysis indicated that PAC-containing as well as PAC-depleted cranberry extracts increased the fimH expression in NU14 as part of a feedback mechanism after blocking FimH. For strain 2980 the PAC-containing extract led to up-regulation of P- and F1C-fimbriae, whereas the PAC-depleted extract had no influence on gene expression. V.m. and V.m. extract(≠PAC) did not influence biofilm and curli formation in UPEC strains NU14 and 2980. These data lead to the conclusion that also proanthocyanidin-free cranberry extracts exert antiadhesive activity by interaction with mannose-sensitive type 1 fimbriae of UPEC.

  4. Diarrheagenic Escherichia coli

    PubMed Central

    Nataro, James P.; Kaper, James B.

    1998-01-01

    Escherichia coli is the predominant nonpathogenic facultative flora of the human intestine. Some E. coli strains, however, have developed the ability to cause disease of the gastrointestinal, urinary, or central nervous system in even the most robust human hosts. Diarrheagenic strains of E. coli can be divided into at least six different categories with corresponding distinct pathogenic schemes. Taken together, these organisms probably represent the most common cause of pediatric diarrhea worldwide. Several distinct clinical syndromes accompany infection with diarrheagenic E. coli categories, including traveler’s diarrhea (enterotoxigenic E. coli), hemorrhagic colitis and hemolytic-uremic syndrome (enterohemorrhagic E. coli), persistent diarrhea (enteroaggregative E. coli), and watery diarrhea of infants (enteropathogenic E. coli). This review discusses the current level of understanding of the pathogenesis of the diarrheagenic E. coli strains and describes how their pathogenic schemes underlie the clinical manifestations, diagnostic approach, and epidemiologic investigation of these important pathogens. PMID:9457432

  5. PATHOGENIC ESCHERICHIA COLI

    EPA Science Inventory

    Escherichia coli is a bacterial species which inhabits the gastrointestinal tract of man and warm-blooded animals. Because of the ubiquity of this bacterium in the intestinal flora, it serves as an important indicator organism of fecal contamination. E. coli, aside from serving a...

  6. Distribution of Pathogenic Genes aatA, aap, aggR, among Uropathogenic Escherichia coli (UPEC) and Their Linkage with StbA Gene.

    PubMed

    Nazemi, A; Mirinargasi, M; Merikhi, N; Sharifi, S H

    2011-07-01

    Urinary tract infection (UTI) with E. coli (UPEC) is one of the most common bacterial infections among human beings. In addition to the host predisposing factors, genes are also proposed to have an important role in the occurrence of UTIs. This study investigated the distribution of three pathogenic genes including aggR, aap and aatA among UPEC infected samples and their linkage with stbA, the essential gene for maintaining of pAA plasmid. A total of 244 samples were collected from patients with UTIs through clinical laboratories located in western side of Tehran (Iran) during years 2008-2009. E. coli isolation was performed according to standard laboratory methods. DNAs were extracted from samples using Boiling method, and the presence of aap, aggR, aatA and stbA genes were investigated by PCR. No pathogenic genes (aap, aggR, aatA) were found in 104 out of 244 UPEC samples, while 14 of them were carrying stbA gene. Out of 140 UPEC samples with pathogenic genes, 94 (46.6%) were carrying aap gene, 52 (23%) aggR gene, and 80 (35.4%) aatA gene. A total of 18 samples were also carrying all pathogenic genes together. Moreover, 44 out of 144 samples were carrying stbA gene. The results obtained by this study showed that the aggR, aap and aatA pathogenic genes have different existence patterns in different E. coli strains that infect different organs. Our study also showed that these three plasmid genes in EAEC strains are able to transpose in the genome and change their level of linkage with pAA plasmid essential gene stbA. Meanwhile, this study confirmed that aggR, aap and aatA genes are not specific to only EAEC strains.

  7. Role of Enteroaggregative Escherichia coli Virulence Factors in Uropathogenesis

    PubMed Central

    Boll, Erik J.; Struve, Carsten; Boisen, Nadia; Olesen, Bente; Stahlhut, Steen G.

    2013-01-01

    A multiresistant clonal Escherichia coli O78:H10 strain qualifying molecularly as enteroaggregative Escherichia coli (EAEC) was recently shown to be the cause of a community-acquired outbreak of urinary tract infection (UTI) in greater Copenhagen, Denmark, in 1991. This marks the first time EAEC has been associated with an extraintestinal disease outbreak. Importantly, the outbreak isolates were recovered from the urine of patients with symptomatic UTI, strongly implying urovirulence. Here, we sought to determine the uropathogenic properties of the Copenhagen outbreak strain and whether these properties are conferred by the EAEC-specific virulence factors. We demonstrated that through expression of aggregative adherence fimbriae, the principal adhesins of EAEC, the outbreak strain exhibited pronouncedly increased adherence to human bladder epithelial cells compared to prototype uropathogenic strains. Moreover, the strain was able to produce distinct biofilms on abiotic surfaces, including urethral catheters. These findings suggest that EAEC-specific virulence factors increase uropathogenicity and may have played a significant role in the ability of the strain to cause a community-acquired outbreak of UTI. Thus, inclusion of EAEC-specific virulence factors is warranted in future detection and characterization of uropathogenic E. coli. PMID:23357383

  8. Genetic recombination. [Escherichia coli

    SciTech Connect

    Stahl, F.W.

    1987-02-01

    The molecular pathways of gene recombination are explored and compared in studies of the model organisms, Escherichia coli and phase lambda. In the discussion of data from these studies it seems that recombination varies with the genetic idiosyncrasies of the organism and may also vary within a single organism.

  9. Uropathogenic E.coli (UPEC) Infection Induces Proliferation through Enhancer of Zeste Homologue 2 (EZH2)

    PubMed Central

    Penna, Frank; Samiei, Alaleh Najdi; Sidler, Martin; Jiang, Jia-Xin; Ibrahim, Fadi; Tolg, Cornelia; Delgado-Olguin, Paul; Rosenblum, Norman; Bägli, Darius J.

    2016-01-01

    Host-pathogen interactions can induce epigenetic changes in the host directly, as well as indirectly through secreted factors. Previously, uropathogenic Escherichia coli (UPEC) was shown to increase DNA methyltransferase activity and expression, which was associated with methylation-dependent alterations in the urothelial expression of CDKN2A. Here, we showed that paracrine factors from infected cells alter expression of another epigenetic writer, EZH2, coordinate with proliferation. Urothelial cells were inoculated with UPEC, UPEC derivatives, or vehicle (mock infection) at low moi, washed, then maintained in media with Gentamycin. Urothelial conditioned media (CM) and extracellular vesicles (EV) were isolated after the inoculations and used to treat naïve urothelial cells. EZH2 increased with UPEC infection, inoculation-induced CM, and inoculation-induced EV vs. parallel stimulation derived from mock-inoculated urothelial cells. We found that infection also increased proliferation at one day post-infection, which was blocked by the EZH2 inhibitor UNC1999. Inhibition of demethylation at H3K27me3 had the opposite effect and augmented proliferation. CONCLUSION: Uropathogen-induced paracrine factors act epigenetically by altering expression of EZH2, which plays a key role in early host cell proliferative responses to infection. PMID:26964089

  10. Pathogenicity islands of uropathogenic E. coli and the evolution of virulence.

    PubMed

    Oelschlaeger, T A; Dobrindt, U; Hacker, J

    2002-06-01

    Uropathogenic Escherichia coli (UPEC) are the most important group of microorganisms responsible for urinary tract infection. UPEC differ from non-pathogenic E. coli and from other E. coli pathotypes by the production of specific virulence factors, which enable the bacteria to adhere to uroepithelial cells and to establish urinary tract infections. Besides adherence factors, toxins, 'modulins', capsules, iron uptake systems and other bacterial products contribute to the virulence of the strains. The respective genes are frequently located on large pieces of DNA called 'pathogenicity islands' (PAIs). PAIs form (unstable) regions of the genome of UPECs, which are often associated with tRNA genes. Using various molecular techniques, the functions of PAI encoded gene products have been studied. The usage of DNA arrays give answers to questions on the distribution of PAIs among various enterobacteria and on the expression of the different genes under in vitro and in vivo conditions. In addition, assumptions can be made on the evolution of these important pathogens.

  11. Aging of Escherichia coli

    PubMed Central

    Clifton, C. E.

    1966-01-01

    Clifton, C. E. (Stanford University, Stanford, Calif.). Aging of Escherichia coli. J. Bacteriol. 92:905–912. 1966.—The rates of endogenous and exogenous (glucose) respiration decreased much more rapidly than did the viable count during the first 24 hr of aging of washed, C14-labeled cells of Escherichia coli K-12 suspended in a basal salt medium devoid of ammonium salts. The rates of decrease of respiration and of death approached each other as the age of the cells increased, but death was not the only factor involved in decreased respiratory activity of the suspensions. The greatest decrease in cellular contents with aging was noted in the ribonucleic acid fraction, of which the ribose appeared to be oxidized, while uracil accumulated in the suspension medium. The viable count and respiratory activities remained higher in glucose-fed than in nonfed suspensions. Proline-labeled cells fed glucose tended to lose more of their proline and to convert more proline into C14O2 than in unfed controls. On the other hand, uracil-labeled cells fed glucose retained more of the uracil than did nonfed cells, but glucose elicited some oxidation of uracil. An exogenous energy source such as glucose aided in the maintenance of a population, but it was not the only factor needed for such maintenance. PMID:5332874

  12. Molecular cloning and expression of the O4 polysaccharide gene cluster from Escherichia coli.

    PubMed

    Haraguchi, G E; Hull, R A; Krallmann-Wenzel, U; Hull, S I

    1989-02-01

    The Escherichia coli O4 serotype is common among isolates from urinary tract infections. The genes responsible for the biosynthesis of the O4 polysaccharide in a human uropathogenic E. coli were cloned and expressed in E. coli K-12. The recombinant plasmid pGH60, which conferred the O4 phenotype, encoded eight proteins with apparent molecular weights of 39, 36.5, 35, 32.8, 26, 24, 20.7 and 13 kDa.

  13. Modulation of ureteric Ca signaling and contractility in humans and rats by uropathogenic E. coli.

    PubMed

    Floyd, Rachel V; Winstanley, Craig; Bakran, Ali; Wray, Susan; Burdyga, Theodor V

    2010-04-01

    Ascending urinary tract infections, a significant cause of kidney damage, are predominantly caused by uropathogenic Escherichia coli (UPEC). However, the role and mechanism of changes in ureteric function during infection are poorly understood. We therefore investigated the effects of UPEC on Ca signaling and contractions in rat (n = 17) and human (n = 6) ureters. Ca transients and force were measured and effects of UPEC on the urothelium were monitored in live tissues. In both species, luminal exposure of ureters to UPEC strains J96 and 536 caused significant time-dependent decreases in phasic and high K depolarization-induced contractility, associated with decreases in the amplitude and duration of the Ca transients. These changes were significant after 3-5 h and irreversible over the next 5 h. The infection causes increased activity of K channels, causing inhibition of voltage-gated Ca entry, and K channel blockers could reverse the effects of UPEC on ureteric function. A smaller direct effect on Ca entry also occurs. Nonpathogenic E. coli (TG2) or abluminal application of UPEC did not produce changes in Ca signaling or contractility. UPEC exposure also caused significant impairment of urothelial barrier function; luminal application of the Ca channel blocker nifedipine caused a reduction in contractions as it entered the tissue, an effect not observed in untreated ureters. Thus, UPEC impairs ureteric contractility in a Ca-dependent manner, largely caused by stimulation of potassium channels and this mechanism is dependent on host-urothelium interaction.

  14. Community behavior and amyloid-associated phenotypes among a panel of uropathogenic E. coli.

    PubMed

    Lim, Ji Youn; Pinkner, Jerome S; Cegelski, Lynette

    2014-01-10

    Uropathogenic Escherichia coli (UPEC) are the major causative agents of urinary tract infection and engage in a coordinated genetic and molecular cascade to colonize the urinary tract. Disrupting the assembly and/or function of virulence factors and bacterial biofilms has emerged as an attractive target for the development of new therapeutic strategies to prevent and treat urinary tract infection, particularly in the era of increasing antibiotic resistance among human pathogens. UPEC vary widely in their genetic and molecular phenotypes and more data are needed to understand the features that distinguish isolates as more or less virulent and as more robust biofilm formers or poor biofilm formers. Curli are extracellular functional amyloid fibers produced by E. coli that contribute to pathogenesis and influence the host response during urinary tract infection (UTI). We have examined the production of curli and curli-associated phenotypes including biofilm formation among a specific panel of human clinical UPEC that has been studied extensively in the mouse model of UTI. Motility, curli production, and curli-associated biofilm formation attached to plastic were the most prevalent behaviors, shared by most clinical isolates. We discuss these results in the context on the previously reported behavior and phenotypes of these isolates in the murine cystitis model in vivo.

  15. Distribution of the Serine Protease Autotransporters of the Enterobacteriaceae among Extraintestinal Clinical Isolates of Escherichia coli

    PubMed Central

    Parham, Nick J.; Pollard, Samantha J.; Desvaux, Mickaël; Scott-Tucker, Anthony; Liu, Chengjie; Fivian, Amanda; Henderson, Ian R.

    2005-01-01

    Urinary tract infections continue to be among the most common extraintestinal diseases. Cystitis in women is by far the most common urinary tract infection; pyelonephritis in both sexes and prostatitis in men are more severe but less frequent complaints. Escherichia coli is by far the most common cause of urinary tract infection. It is believed that uropathogenic E. coli is adept at colonizing the urinary tract via the production of specific virulence factors. Recently, a novel virulence determinant, Vat, was described for the prototypical uropathogenic E. coli strain CFT073. Vat is a member of the SPATE (serine protease autotransporters of the Enterobacteriaceae) subfamily of the autotransporters. Previously, SPATEs have been described for all pathovars of E. coli, but until recently their presence had been noticeably absent in nonpathogenic E. coli. In this report we describe the prevalence and phylogenetic distribution of the SPATEs among uropathogenic E. coli and the ECOR collection, demonstrating an association between the presence of the SPATEs, including Vat, and uropathogenic E. coli phylogroups. In addition, we describe the distribution of SPATEs among nonpathogenic E. coli. PMID:16081954

  16. Biogenesis of F7(1) and F7(2) fimbriae of uropathogenic Escherichia coli: influence of the FsoF and FstFG proteins and localization of the Fso/FstE protein.

    PubMed

    Riegman, N; van Die, I; Leunissen, J; Hoekstra, W; Bergmans, H

    1988-01-01

    The F7(1) and F7(2) P-fimbriae of Escherichia coli are encoded by the fso (F seven one) and fst (F seven two) gene clusters, respectively (Van Die et al., 1984; 1985). With the immunocytochemical gold-labelling technique it was demonstrated that both the FsoE and FstE proteins are non-adhesive minor fimbrial subunits located at the tip of the fimbrial structure. The FsoF and FstFG proteins play an important role in the initiation of polymerization of the minor and major subunits into the fimbrial structure.

  17. Measuring Escherichia coli Gene Expression during Human Urinary Tract Infections

    PubMed Central

    Mobley, Harry L. T.

    2016-01-01

    Extraintestinal Escherichia coli (E. coli) evolved by acquisition of pathogenicity islands, phage, plasmids, and DNA segments by horizontal gene transfer. Strains are heterogeneous but virulent uropathogenic isolates more often have specific fimbriae, toxins, and iron receptors than commensal strains. One may ask whether it is the virulence factors alone that are required to establish infection. While these virulence factors clearly contribute strongly to pathogenesis, bacteria must survive by metabolizing nutrients available to them. By constructing mutants in all major metabolic pathways and co-challenging mice transurethrally with each mutant and the wild type strain, we identified which major metabolic pathways are required to infect the urinary tract. We must also ask what else is E. coli doing in vivo? To answer this question, we examined the transcriptome of E. coli CFT073 in the murine model of urinary tract infection (UTI) as well as for E. coli strains collected and analyzed directly from the urine of patients attending either a urology clinic or a university health clinic for symptoms of UTI. Using microarrays and RNA-seq, we measured in vivo gene expression for these uropathogenic E. coli strains, identifying genes upregulated during murine and human UTI. Our findings allow us to propose a new definition of bacterial virulence. PMID:26784237

  18. [Comparison of routine use of two chromogenic media ChromID CPS (bioMérieux) and UriSelect4 (Bio-Rad) for the detection of Escherichia coli and major uropathogenics in urine].

    PubMed

    Meddeb, Mariam; Maurer, Maxime; Grillon, Antoine; Scheftel, Jean-Michel; Jaulhac, Benoît

    2014-01-01

    Escherichia coli is the most common bacterial cause of urinary tract infections. Its rapid and specific identification in urine samples represents a major challenge within the rendering results and optimizing the management of the patient. We aimed to compare the sensitivity and specificity of two commercially available chromogenic media for E. coli: ChromID CPS (Biomérieux) and UriSelect4 (Bio(-)Rad), without carrying out further tests. 99 consecutive and non-redundant urine samples considered to be infected were simultaneously plated onto blood agar and the two chromogenic media. Colony color and bacterial growth quantification were compared 18 and 48 hours after incubation. Bacteria were identified with mass spectrometry. A complementary analysis on 80 bacterial strains known to pose potential identification problems was performed. 43 urines samples grew E. coli, and 42 of them were pink-colored on the two chromogenic mediums, as expected (sensibility=97.7%). Growth quantification was significantly greater on blood agar than on chromogenic media (p<0.001).We noted specificity issues at the complementary analysis with the UriSelect4 medium: Citrobacter freundii and some strains of Citrobacter brakii, Enterobacter cloacae and Hafnia alvei were pink-colored, and could be misidentified as E. coli. ChromID CPS medium did not show such misidentification. In conclusion, the agar ChromID CPS proved to be greater than the UriSelect4 agar in our work in terms of specificity of direct identification of E. Coli, without the use of additional test. PMID:24736143

  19. The DraC usher in Dr fimbriae biogenesis of uropathogenic E. coli Dr(+) strains.

    PubMed

    Zalewska-Piatek, Beata; Kur, Marta; Wilkanowicz, Sabina; Piatek, Rafał; Kur, Józef

    2010-05-01

    Biogenesis of Dr fimbriae encoded by the dra gene cluster of uropathogenic Escherichia coli strains requires the chaperone-usher pathway. This secretion system is based on two non-structural assembly components, the DraB periplasmic chaperone and DraC outer-membrane usher. The DraB controls the folding of DraE subunits, and DraC forms the assembly and secretion platform for polymerization of subunits in linear fibers. In this study, mutagenesis of the DraC N-terminus was undertaken to select residues critical for Dr fimbriae bioassembly. The DraC-F4A, DraC-C64, DraC-C100A and DraC-W142A significantly reduced the adhesive ability of E. coli strains. The biological activity of the DraC mutants as a assembly platform for Dr fimbriae polymerization was verified by agglutination of human erythrocytes and adhesion to DAF localized at the surface of CHO-DAF(+) and HeLa cells. The residue F4 of the DraC usher conserved among FGL and FGS chaperone-assembled adhesive organelles can be used to design pillicides blocking the biogenesis of Dr fimbriae. Because the draC and afaC-III genes share 100% identity the range of the virulence determinant inhibitors could also be extended to E. coli strains encoding afa-3 gene cluster. The investigations performed showed that the usher N-terminus plays an important role in biogenesis of complete fiber.

  20. Extraintestinal pathogenic Escherichia coli.

    PubMed

    Smith, James L; Fratamico, Pina M; Gunther, Nereus W

    2007-01-01

    Extraintestinal pathogenic Escherichia coli (ExPEC) possesses virulence traits that allow it to invade, colonize, and induce disease in bodily sites outside of the gastrointestinal tract. Human diseases caused by ExPEC include urinary tract infections, neonatal meningitis, sepsis, pneumonia, surgical site infections, as well as infections in other extraintestinal locations. ExPEC-induced diseases represent a large burden in terms of medical costs and productivity losses. In addition to human illnesses, ExPEC strains also cause extraintestinal infections in domestic animals and pets. A commonality of virulence factors has been demonstrated between human and animal ExPEC, suggesting that the organisms are zoonotic pathogens. ExPEC strains have been isolated from food products, in particular from raw meats and poultry, indicating that these organisms potentially represent a new class of foodborne pathogens. This review discusses various aspects of ExPEC, including its presence in food products, in animals used for food or as companion pets; the diseases ExPEC can cause; and the virulence factors and virulence mechanisms that cause disease.

  1. Cytoprotective Effect of Lactobacillus crispatus CTV-05 against Uropathogenic E. coli

    PubMed Central

    Butler, Daniel S. C.; Silvestroni, Aurelio; Stapleton, Ann E.

    2016-01-01

    The vaginal flora consists of a subset of different lactic acid producing bacteria, typically creating a hostile environment for infecting pathogens. However, the flora can easily be disrupted, creating a favorable milieu for uropathogenic Escherichia coli (UPEC), making it possible to further infect the urinary system via the urethra. Probiotic use of different lactobacilli to restore the normal flora of the vagina has been proposed as a potential prophylactic treatment against urinary tract infections. This project evaluated the protective- and anti-inflammatory roles of the probiotic Lactobacillus crispatus strain CTV-05 in an in vitro system. The inflammatory response and the cytotoxic effect were studied by Enzyme-linked immunosorbent assays and by trypan blue exclusion of cells inoculated with L. crispatus CTV-05 and comparing it to non-infected controls and UPEC infected cells. L. crispatus CTV-05 showed no cytotoxicity to vaginal epithelial cells compared to non-infected controls and provided significant protection against UPEC infection (p < 0.05). Further more, L. crispatus CTV-05 did not create a pro-inflammatory response in vitro, with no significant increase of IL-1β or IL-6. These results demonstrate the protective effect of using L. crispatus CTV-05 as a probiotic treatment to reduce the risk of recurrent urinary tract infections.

  2. Establishment of a Persistent Escherichia coli Reservoir during the Acute Phase of a Bladder Infection

    PubMed Central

    Mulvey, Matthew A.; Schilling, Joel D.; Hultgren, Scott J.

    2001-01-01

    The vast majority of urinary tract infections are caused by strains of uropathogenic Escherichia coli that encode filamentous adhesive organelles called type 1 pili. These structures mediate both bacterial attachment to and invasion of bladder epithelial cells. However, the mechanism by which type 1 pilus-mediated bacterial invasion contributes to the pathogenesis of a urinary tract infection is unknown. Here we show that type 1-piliated uropathogens can invade the superficial epithelial cells that line the lumenal surface of the bladder and subsequently replicate, forming massive foci of intracellular E. coli termed bacterial factories. In response to infection, superficial bladder cells exfoliate and are removed with the flow of urine. To avoid clearance by exfoliation, intracellular uropathogens can reemerge and eventually establish a persistent, quiescent bacterial reservoir within the bladder mucosa that may serve as a source for recurrent acute infections. These observations suggest that urinary tract infections are more chronic and invasive than generally assumed. PMID:11402001

  3. EXTRAINTESTINAL PATHOGENIC ESCHERICHIA COLI (EXPEC)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Extraintestinal pathogenic Escherichia coli (ExPEC) possess virulence traits that allow them to invade, colonize, and induce disease in bodily sites outside of the gastrointestinal tract. Human diseases caused by ExPEC include urinary tract infections, neonatal meningitis, sepsis, pneumonia, surgic...

  4. Multidrug resistance and high virulence genotype in uropathogenic Escherichia coli due to diffusion of ST131 clonal group producing CTX-M-15: an emerging problem in a Tunisian hospital.

    PubMed

    Ferjani, Sana; Saidani, Mabrouka; Ennigrou, Samir; Hsairi, Mohamed; Slim, Amine Faouzi; Ben Boubaker, Ilhem Boutiba

    2014-05-01

    A collection of 201 Escherichia coli strains isolated from urine of patients in a Tunisian hospital between January 2006 and July 2008 was studied. Microbial identification was done by conventional methods, and antibiotic susceptibility with disk diffusion method was performed according to the Clinical Laboratory and Standards Institute guidelines. Detection of extended-spectrum beta-lactamase (ESBL) was performed by double-disk synergy test (DDST) and identification was done by PCR and sequencing. ESBL-producing isolates were subjected to molecular typing by random amplified polymorphic DNA (RAPD) and ST131 detection by PCR. Four phylogenetic groups (A, B1, B2 and D), 18 virulence genes and CTX-M group were individualized using PCR. Statistical analysis was done by Pearson χ2 test and Mann-Whitney U test. The strains were recovered primarily from urology (28%), maternity (19%) and medicine (16%) wards. Antibiotic resistance rates were ampicilin (72.1%), nalidixic acid (41.8%), ciprofloxacin (38.8%), gentamicin (23.9%) and cefotaxime (17.4%). Thirty-one of cefotaxime-resistant isolates (n = 35) had a positive DDST and harboured bla CTX-M-15 gene. Twenty of them (64.5%) belonged to the ST131 clone and showed the same RAPD DNA profile. Ciprofloxacin- and cotrimoxazole-susceptible isolates were significantly associated with phylogenetic group B2, whereas isolates that were resistant to these molecules were associated with B1 and D phylogenetic groups, respectively. Virulence genes were significantly more frequent among ciprofloxacin- and cotrimoxazole-susceptible strains than those resistant to these antibiotics. However, CXT-M-15-producing isolates were associated with many virulence genes. Isolates concomitantly susceptible to the three antimicrobials agents (ciprofloxacin, cefotaxime and cotrimoxazole) were significantly associated with group B2 and high virulence score, whereas isolates with resistance patterns especially those including resistance to

  5. Shiga Toxin Producing Escherichia coli.

    PubMed

    Bryan, Allen; Youngster, Ilan; McAdam, Alexander J

    2015-06-01

    Shiga toxin-producing Escherichia coli (STEC) is among the common causes of foodborne gastroenteritis. STEC is defined by the production of specific toxins, but within this pathotype there is a diverse group of organisms. This diversity has important consequences for understanding the pathogenesis of the organism, as well as for selecting the optimum strategy for diagnostic testing in the clinical laboratory. This review includes discussions of the mechanisms of pathogenesis, the range of manifestations of infection, and the several different methods of laboratory detection of Shiga toxin-producing E coli.

  6. Curli fimbria: an Escherichia coli adhesin associated with human cystitis.

    PubMed

    Cordeiro, Melina Aparecida; Werle, Catierine Hirsch; Milanez, Guilherme Paier; Yano, Tomomasa

    2016-01-01

    Escherichia coli is the major causative agent of human cystitis. In this study, a preliminary molecular analysis carried out by PCR (polymerase chain reaction) demonstrated that 100% of 31 E. coli strains isolated from patients with recurrent UTIs (urinary tract infections) showed the presence of the curli fimbria gene (csgA). Curli fimbria is known to be associated with bacterial biofilm formation but not with the adhesion of human cystitis-associated E. coli. Therefore, this work aimed to study how curli fimbria is associated with uropathogenic E. coli (UPEC) as an adhesion factor. For this purpose, the csgA gene was deleted from strain UPEC-4, which carries three adhesion factor genes (csgA, fimH and ompA). The wild-type UPEC-4 strain and its mutant (ΔcsgA) were analyzed for their adhesion ability over HTB-9 (human bladder carcinoma), Vero (kidney cells of African green monkey) and HUVEC (human umbilical vein) cells in the presence of α-d-mannose. All the wild-type UPEC strains tested (100%) were able to adhere to all three cell types, while the UPEC-4 ΔcsgA mutant lost its adherence to HTB-9 but continued to adhere to the HUVEC and Vero cells. The results suggest that curli fimbria has an important role in the adhesion processes associated with human UPEC-induced cystitis.

  7. Host-Pathogen Checkpoints and Population Bottlenecks in Persistent and Intracellular Uropathogenic E. coli Bladder Infection

    PubMed Central

    Hannan, Thomas J.; Totsika, Makrina; Mansfield, Kylie J.; Moore, Kate H.; Schembri, Mark A.; Hultgren, Scott J.

    2013-01-01

    Bladder infections affect millions of people yearly, and recurrent symptomatic infections (cystitis) are very common. The rapid increase in infections caused by multi-drug resistant uropathogens threatens to make recurrent cystitis an increasingly troubling public health concern. Uropathogenic E. coli (UPEC) cause the vast majority of bladder infections. Upon entry into the lower urinary tract, UPEC face obstacles to colonization that constitute population bottlenecks, reducing diversity and selecting for fit clones. A critical mucosal barrier to bladder infection is the epithelium (urothelium). UPEC bypass this barrier when they invade urothelial cells and form intracellular bacterial communities (IBCs), a process which requires type 1 pili. IBCs are transient in nature, occurring primarily during acute infection. Chronic bladder infection is common and can be either latent, in the form of the Quiescent Intracellular Reservoir (QIR), or active, in the form of asymptomatic bacteriuria (ASB/ABU) or chronic cystitis. In mice, the fate of bladder infection: QIR, ASB, or chronic cystitis, is determined within the first 24 hours of infection and constitutes a putative host-pathogen mucosal checkpoint that contributes to susceptibility to recurrent cystitis. Knowledge of these checkpoints and bottlenecks is critical for our understanding of bladder infection and efforts to devise novel therapeutic strategies. PMID:22404313

  8. Nonchemotactic Mutants of Escherichia coli

    PubMed Central

    Armstrong, John B.; Adler, Julius; Dahl, Margaret M.

    1967-01-01

    We have isolated 40 mutants of Escherichia coli which are nonchemotactic as judged by their failure to swarm on semisolid tryptone plates or to make bands in capillary tubes containing tryptone broth. All the mutants have normal flagella, a fact shown by their shape and reaction with antiflagella serum. All are fully motile under the microscope and all are sensitive to the phage chi. Unlike its parent, one of the mutants, studied in greater detail, failed to show chemotaxis toward oxygen, glucose, serine, threonine, or aspartic acid. The failure to exhibit chemotaxis does not result from a failure to use the chemicals. The swimming of this mutant was shown to be random. The growth rate was normal under several conditions, and the growth requirements were unchanged. Images PMID:5335897

  9. Peptidoglycan Hydrolases of Escherichia coli

    PubMed Central

    van Heijenoort, Jean

    2011-01-01

    Summary: The review summarizes the abundant information on the 35 identified peptidoglycan (PG) hydrolases of Escherichia coli classified into 12 distinct families, including mainly glycosidases, peptidases, and amidases. An attempt is also made to critically assess their functions in PG maturation, turnover, elongation, septation, and recycling as well as in cell autolysis. There is at least one hydrolytic activity for each bond linking PG components, and most hydrolase genes were identified. Few hydrolases appear to be individually essential. The crystal structures and reaction mechanisms of certain hydrolases having defined functions were investigated. However, our knowledge of the biochemical properties of most hydrolases still remains fragmentary, and that of their cellular functions remains elusive. Owing to redundancy, PG hydrolases far outnumber the enzymes of PG biosynthesis. The presence of the two sets of enzymes acting on the PG bonds raises the question of their functional correlations. It is difficult to understand why E. coli keeps such a large set of PG hydrolases. The subtle differences in substrate specificities between the isoenzymes of each family certainly reflect a variety of as-yet-unidentified physiological functions. Their study will be a far more difficult challenge than that of the steps of the PG biosynthesis pathway. PMID:22126997

  10. BarA-UvrY two-component system regulates virulence of uropathogenic E. coli CFT073.

    PubMed

    Palaniyandi, Senthilkumar; Mitra, Arindam; Herren, Christopher D; Lockatell, C Virginia; Johnson, David E; Zhu, Xiaoping; Mukhopadhyay, Suman

    2012-01-01

    Uropathogenic Escherichia coli (UPEC), a member of extraintestinal pathogenic E. coli, cause ∼80% of community-acquired urinary tract infections (UTI) in humans. UPEC initiates its colonization in epithelial cells lining the urinary tract with a complicated life cycle, replicating and persisting in intracellular and extracellular niches. Consequently, UPEC causes cystitis and more severe form of pyelonephritis. To further understand the virulence characteristics of UPEC, we investigated the roles of BarA-UvrY two-component system (TCS) in regulating UPEC virulence. Our results showed that mutation of BarA-UvrY TCS significantly decreased the virulence of UPEC CFT073, as assessed by mouse urinary tract infection, chicken embryo killing assay, and cytotoxicity assay on human kidney and uroepithelial cell lines. Furthermore, mutation of either barA or uvrY gene reduced the production of hemolysin, lipopolysaccharide (LPS), proinflammatory cytokines (TNF-α and IL-6) and chemokine (IL-8). The virulence phenotype was restored similar to that of wild-type by complementation of either barA or uvrY gene in trans. In addition, we discussed a possible link between the BarA-UvrY TCS and CsrA in positively and negatively controlling virulence in UPEC. Overall, this study provides the evidences for BarA-UvrY TCS regulates the virulence of UPEC CFT073 and may point to mechanisms by which virulence regulations are observed in different ways may control the long-term survival of UPEC in the urinary tract.

  11. Structure of Escherichia coli tryptophanase.

    PubMed

    Ku, Shao Yang; Yip, Patrick; Howell, P Lynne

    2006-07-01

    Pyridoxal 5'-phosphate (PLP) dependent tryptophanase has been isolated from Escherichia coli and its crystal structure has been determined. The structure shares the same fold with and has similar quaternary structure to Proteus vulgaris tryptophanase and tyrosine-phenol lyase, but is found in a closed conformation when compared with these two enzymes. The tryptophanase structure, solved in its apo form, does not have covalent PLP bound in the active site, but two sulfate ions. The sulfate ions occupy the phosphoryl-binding site of PLP and the binding site of the alpha-carboxyl of the natural substrate tryptophan. One of the sulfate ions makes extensive interactions with both the transferase and PLP-binding domains of the protein and appears to be responsible for holding the enzyme in its closed conformation. Based on the sulfate density and the structure of the P. vulgaris enzyme, PLP and the substrate tryptophan were modeled into the active site. The resulting model is consistent with the roles of Arg419 in orienting the substrate to PLP and acidifying the alpha-proton of the substrate for beta-elimination, Lys269 in the formation and decomposition of the PLP quinonoid intermediate, Arg230 in orienting the substrate-PLP intermediates in the optimal conformation for catalysis, and His463 and Tyr74 in determining substrate specificity and suggests that the closed conformation observed in the structure could be induced by substrate binding and that significant conformational changes occur during catalysis. A catalytic mechanism for tryptophanase is proposed. Since E. coli tryptophanase has resisted forming diffraction-quality crystals for many years, the molecular surface of tryptophanase has been analyzed in various crystal forms and it was rationalized that strong crystal contacts occur on the flat surface of the protein and that the size of crystal contact surface seems to correlate with the diffraction quality of the crystal.

  12. Escherichia coli Isolates That Carry vat, fyuA, chuA, and yfcV Efficiently Colonize the Urinary Tract

    PubMed Central

    Spurbeck, Rachel R.; Dinh, Paul C.; Walk, Seth T.; Stapleton, Ann E.; Hooton, Thomas M.; Nolan, Lisa K.; Kim, Kwang Sik; Johnson, James R.

    2012-01-01

    Extraintestinal Escherichia coli (ExPEC), a heterogeneous group of pathogens, encompasses avian, neonatal meningitis, and uropathogenic E. coli strains. While several virulence factors are associated with ExPEC, there is no core set of virulence factors that can be used to definitively differentiate these pathotypes. Here we describe a multiplex of four virulence factor-encoding genes, yfcV, vat, fyuA, and chuA, highly associated with uropathogenic E. coli strains that can distinguish three groups of E. coli: diarrheagenic and animal-associated E. coli strains, human commensal and avian pathogenic E. coli strains, and uropathogenic and neonatal meningitis E. coli strains. Furthermore, human intestinal isolates that encode all four predictor genes express them during exponential growth in human urine and colonize the bladder in the mouse model of ascending urinary tract infection in higher numbers than human commensal strains that do not encode the four predictor genes (P = 0.02), suggesting that the presence of the predictors correlates with uropathogenic potential. PMID:22966046

  13. Succinate production in Escherichia coli

    PubMed Central

    Thakker, Chandresh; Martínez, Irene; San, Ka-Yiu; Bennett, George N.

    2012-01-01

    Succinate has been recognized as an important platform chemical that can be produced from biomass. While a number of organisms are capable of succinate production naturally, this review focuses on the engineering of Escherichia coli for production of the four-carbon dicarboxylic acid. Important features of a succinate production system are to achieve optimal balance of reducing equivalents generated by consumption of the feedstock, while maximizing the amount of carbon that is channeled to the product. Aerobic and anaerobic production strains have been developed and applied to production from glucose as well as other abundant carbon sources. Metabolic engineering methods and strain evolution have been used and supplemented by the recent application of systems biology and in silico modeling tools to construct optimal production strains. The metabolic capacity of the production strain, as well as the requirement for efficient recovery of succinate and the reliability of the performance under scale-up are important in the overall process. The costs of the overall biorefinery compatible process will determine the economical commercialization of succinate and its impact in larger chemical markets. PMID:21932253

  14. Murein segregation in Escherichia coli.

    PubMed Central

    de Pedro, M A; Quintela, J C; Höltje, J V; Schwarz, H

    1997-01-01

    Peptidoglycan (murein) segregation has been studied by means of a new labeling method. The method relies on the ability of Escherichia coli cells to incorporate D-Cys into macromolecular murein. The incorporation depends on a periplasmic amino acid exchange reaction. At low concentrations, D-Cys is innocuous to the cell. The distribution of modified murein in purified sacculi can be traced and visualized by immunodetection of the -SH groups by fluorescence and electron microscopy techniques. Analysis of murein segregation in wild-type and cell division mutant strains revealed that murein in polar caps is metabolically inert and is segregated in a conservative fashion. Elongation of the sacculus apparently occurs by diffuse insertion of precursors over the cylindrical part of the cell surface. At the initiation of cell division, there is a FtsZ-dependent localized activation of murein synthesis at the potential division sites. Penicillin-binding protein 3 and the products of the division genes ftsA and ftsQ are dispensable for the activation of division sites. As a consequence, under restrictive conditions ftsA,ftsI,or ftsQ mutants generate filamentous sacculi with rings of all-new murein at the positions where septa would otherwise develop. PMID:9139895

  15. Escherichia coli survival in waters: Temperature dependence

    EPA Science Inventory

    Knowing the survival rates of water-borne Escherichia coli is important in evaluating microbial contamination and making appropriate management decisions. E. coli survival rates are dependent on temperature, a dependency that is routinely expressed using an analogue of the Q10 mo...

  16. Strategies for Protein Overproduction in Escherichia coli.

    ERIC Educational Resources Information Center

    Mott, John E.

    1984-01-01

    Examines heterologous expression in Escherichia coli and the role of regulatory sequences which control gene expression at transcription resulting in abundant production of messenger RNA and regulatory sequences in mRNA which promote efficient translation. Also examines the role of E. coli cells in stabilizing mRNA and protein that is…

  17. Fosfomycin Resistance in Escherichia coli, Pennsylvania, USA.

    PubMed

    Alrowais, Hind; McElheny, Christi L; Spychala, Caressa N; Sastry, Sangeeta; Guo, Qinglan; Butt, Adeel A; Doi, Yohei

    2015-11-01

    Fosfomycin resistance in Escherichia coli is rare in the United States. An extended-spectrum β-lactamase-producing E. coli clinical strain identified in Pennsylvania, USA, showed high-level fosfomycin resistance caused by the fosA3 gene. The IncFII plasmid carrying this gene had a structure similar to those found in China, where fosfomycin resistance is commonly described.

  18. Effect of 2,4-Dichlorophenoxyacetic acid herbicide Escherichia coli growth, chemical, composition, and cellular envelope

    USGS Publications Warehouse

    Carr, R.S.; Biedenbach, J.M.; Hooten, R.L.

    2001-01-01

    2,4-Dichlorophenoxyacetic acid (2,4-D) is a herbicide widely used in the world and mainly excreted by the renal route in exposed humans and animals. Herbicides can affect other nontarget organisms, such as Escherichia coli. We observed that a single exposure to 1 mM 2,4-D diminished growth and total protein content in all E. coli strains tested in vitro. In addition, successive exposures to 0.01 mM 2,4-D had a toxic effect decreasing growth up to early stationary phase. Uropathogenic E. coli adhere to epithelial cells mediated by fimbriae, adhesins, and hydrophobic properties. 2,4-D exposure of uropathogenic E. coli demonstrated altered hydrophobicity and fimbriation. Hydrophobicity index values obtained by partition in p-xylene/water were 300-420% higher in exposed cells than in control ones. Furthermore, values of hemagglutination titer, protein contents in fimbrial crude extract, and electron microscopy demonstrated a significant diminution of fimbriation in treated cells. Other envelope alterations could be detected, such as lipoperoxidation, evidenced by decreased polyunsaturated fatty acids and increased lipid degradation products (malonaldehyde), and motility diminution. These alterations decreased cell adherence to erythrocytes, indicating a diminished pathogenic capacity of the 2,4-D-exposed E. coli. ?? 2001 by John Wiley & Sons, Inc.

  19. Growth rate of Escherichia coli.

    PubMed Central

    Marr, A G

    1991-01-01

    It should be possible to predict the rate of growth of Escherichia coli of a given genotype in a specified environment. The idea that the rate of synthesis of ATP determines the rate of growth and that the yield of ATP determines the yield of growth is entrenched in bacterial physiology, yet this idea is inconsistent with experimental results. In minimal media the growth rate and yield vary with the carbon source in a manner independent of the rate of formation and yield of ATP. With acetate as the carbon source, anapleurotic reactions, not ATP synthesis, limit the growth rate. For acetate and other gluconeogenic substrates the limiting step appears to be the formation of triose phosphate. I conclude that the rate of growth is controlled by the rate of formation of a precursor metabolite and, thus, of monomers such as amino acids derived from it. The protein-synthesizing system is regulated according to demand for protein synthesis. I examine the conjecture that the signal for this regulation is the ratio of uncharged tRNA to aminoacyl-tRNA, that this signal controls the concentration of guanosine tetraphosphate, and that the concentration of guanosine tetraphosphate controls transcription of rrn genes. Differential equations describing this system were solved numerically for steady states of growth; the computed values of ribosomes and guanosine tetraphosphate and the maximal growth rate agree with experimental values obtained from the literature of the past 35 years. These equations were also solved for dynamical states corresponding to nutritional shifts up and down. PMID:1886524

  20. Clinical Implications of Enteroadherent Escherichia coli

    PubMed Central

    Arenas-Hernández, Margarita M.P.; Martínez-Laguna, Ygnacio; Torres, Alfredo G.

    2012-01-01

    Pathogenic Escherichia coli that colonize the small intestine primarily cause gastrointestinal illness in infants and travelers. The main categories of pathogenic E. coli that colonize the epithelial lining of the small intestine are enterotoxigenic E. coli enteropathogenic E. coli and enteroaggregative E. coli. These organisms accomplish their pathogenic process by a complex, coordinated multistage strategy, including non-intimate adherence mediated by various adhesins. These so called “enteroadherent E. coli ” categories subsequently produced toxins or effector proteins that are either secreted to the milieu or injected to the host cell. Finally, destruction of the intestinal microvilli results from the intimate adherence or the toxic effect exerted over the epithelia, resulting in water secretion and diarrhea. In this review, we summarize the current state of knowledge regarding these enteroadherent E. coli strains and the present clinical understanding of how these organisms colonize the human intestine and cause disease. PMID:22798032

  1. Infection strategies of enteric pathogenic Escherichia coli

    PubMed Central

    Clements, Abigail; Young, Joanna C.; Constantinou, Nicholas; Frankel, Gad

    2012-01-01

    Enteric Escherichia coli (E. coli) are both natural flora of humans and important pathogens causing significant morbidity and mortality worldwide. Traditionally enteric E. coli have been divided into 6 pathotypes, with further pathotypes often proposed. In this review we suggest expansion of the enteric E. coli into 8 pathotypes to include the emerging pathotypes of adherent invasive E. coli (AIEC) and Shiga-toxin producing enteroaggregative E. coli (STEAEC). The molecular mechanisms that allow enteric E. coli to colonize and cause disease in the human host are examined and for two of the pathotypes that express a type 3 secretion system (T3SS) we discuss the complex interplay between translocated effectors and manipulation of host cell signaling pathways that occurs during infection. PMID:22555463

  2. Clinical implications of enteroadherent Escherichia coli.

    PubMed

    Arenas-Hernández, Margarita M P; Martínez-Laguna, Ygnacio; Torres, Alfredo G

    2012-10-01

    Pathogenic Escherichia coli that colonize the small intestine primarily cause gastrointestinal illness in infants and travelers. The main categories of pathogenic E. coli that colonize the epithelial lining of the small intestine are enterotoxigenic E. coli, enteropathogenic E. coli, and enteroaggregative E. coli. These organisms accomplish their pathogenic process by a complex, coordinated multistage strategy, including nonintimate adherence mediated by various adhesins. These so called "enteroadherent E. coli" categories subsequently produce toxins or effector proteins that are either secreted to the milieu or injected to the host cell. Finally, destruction of the intestinal microvilli results from the intimate adherence or the toxic effect exerted over the epithelia, resulting in water secretion and diarrhea. In this review, we summarize the current state of knowledge regarding these enteroadherent E. coli strains and the present clinical understanding of how these organisms colonize the human intestine and cause disease. PMID:22798032

  3. Uropathogenic E. coli infection provokes epigenetic downregulation of CDKN2A (p16INK4A) in uroepithelial cells.

    PubMed

    Tolg, Cornelia; Sabha, Nesrin; Cortese, Rene; Panchal, Trupti; Ahsan, Alya; Soliman, Ashraf; Aitken, Karen J; Petronis, Arturas; Bägli, Darius J

    2011-06-01

    Host cell and bacterial factors determine severity and duration of infections. To allow for bacteria pathogenicity and persistence, bacteria have developed mechanisms that modify expression of host genes involved in cell cycle progression, apoptosis, differentiation and the immune response. Recently, Helicobacter pylori infection of the stomach has been correlated with epigenetic changes in the host genome. To identify epigenetic changes during Escherichia coli induced urinary tract infection (UTI), we developed an in vitro model of persistent infection of human uroepithelial cells with uropathogenic E. coli (UPEC), resulting in intracellular bacteria colonies. Cells inoculated with FimH-negative E. coli (N-UPEC) that are not internalized and non-inoculated cells were used as controls. UPEC infection significantly induced de novo methyltransferase (DNMT) activity (12.5-fold P=0.002 UPEC vs non-inoculated and 250-fold P=0.001 UPEC vs N-UPEC inoculated cells) and Dnmt1 RNA expression (6-fold P=0.04 UPEC vs non-inoculated cells) compared with controls. DNMT1 protein levels were significantly increased in three uroepithelial cell lines (5637, J82, HT-1197) in response to UPEC infection as demonstrated by confocal analysis. Real-time PCR analysis of candidate genes previously associated with bacteria infection and/or innate immunity, revealed UPEC-induced downregulation of the tumor suppressor gene CDKN2A (3.3-fold P=0.007 UPEC vs non-inoculated and 3.3-fold P=0.001 UPEC vs N-UPEC) and the DNA repair gene MGMT (9-fold P=0.03 UPEC vs non-inoculated). Expression of CDH1, MLH1, DAPK1 and TLR4 was not affected. Pyrosequencing of CDKN2A and MGMT CpG islands revealed increased methylation in CDKN2A exon 1 (3.8-fold P=0.04 UPEC vs N-UPEC and UPEC vs non-inoculated). Methylation of MGMT was not affected. UPEC-induced methylation of CDKN2A exon 1 may increase bladder cancer and presage UTI risk, and be useful as a biological marker for UTI susceptibility or recurrence.

  4. Molecular evolution of Salmonella enterica serovar Typhimurium and pathogenic Escherichia coli: from pathogenesis to therapeutics.

    PubMed

    Lavigne, Jean-Philippe; Blanc-Potard, Anne-Béatrice

    2008-03-01

    Salmonella enterica serovar Typhimurium (S. Typhimurium) and certain Escherichia coli are human pathogens that have evolved through the acquisition of multiple virulence determinants by horizontal gene transfer. Similar genetic elements, as pathogenicity islands and virulence plasmids, have driven molecular evolution of virulence in both species. In addition, the contribution of prophages has been recently highlighted as a reservoir for pathogenic diversity. Characterization of horizontally acquired virulence genes has several clinical implications. First, identification of virulence determinants that have a sporadic distribution and are specifically associated with a pathotype and/or a pathology can be useful markers for risk assessment and diagnosis. Secondly, virulence factors widely distributed in pathogenic strains, but absent from non-pathogenic bacteria, are interesting targets for the development of novel antimicrobial chemotherapies and vaccines. Here, we summarize the horizontally acquired virulence factors of S. Typhimurium, enterohemorrhagic E. coli O157:H7 and uropathogenic E. coli, and we describe their use in novel therapeutic approaches.

  5. Uropathogenic E. coli Exploit CEA to Promote Colonization of the Urogenital Tract Mucosa.

    PubMed

    Muenzner, Petra; Kengmo Tchoupa, Arnaud; Klauser, Benedikt; Brunner, Thomas; Putze, Johannes; Dobrindt, Ulrich; Hauck, Christof R

    2016-05-01

    Attachment to the host mucosa is a key step in bacterial pathogenesis. On the apical surface of epithelial cells, members of the human carcinoembryonic antigen (CEA) family are abundant glycoproteins involved in cell-cell adhesion and modulation of cell signaling. Interestingly, several gram-negative bacterial pathogens target these receptors by specialized adhesins. The prototype of a CEACAM-binding pathogen, Neisseria gonorrhoeae, utilizes colony opacity associated (Opa) proteins to engage CEA, as well as the CEA-related cell adhesion molecules CEACAM1 and CEACAM6 on human epithelial cells. By heterologous expression of neisserial Opa proteins in non-pathogenic E. coli we find that the Opa protein-CEA interaction is sufficient to alter gene expression, to increase integrin activity and to promote matrix adhesion of infected cervical carcinoma cells and immortalized vaginal epithelial cells in vitro. These CEA-triggered events translate in suppression of exfoliation and improved colonization of the urogenital tract by Opa protein-expressing E. coli in CEA-transgenic compared to wildtype mice. Interestingly, uropathogenic E. coli expressing an unrelated CEACAM-binding protein of the Afa/Dr adhesin family recapitulate the in vitro and in vivo phenotype. In contrast, an isogenic strain lacking the CEACAM-binding adhesin shows reduced colonization and does not suppress epithelial exfoliation. These results demonstrate that engagement of human CEACAMs by distinct bacterial adhesins is sufficient to blunt exfoliation and to promote host infection. Our findings provide novel insight into mucosal colonization by a common UPEC pathotype and help to explain why human CEACAMs are a preferred epithelial target structure for diverse gram-negative bacteria to establish a foothold on the human mucosa. PMID:27171273

  6. Uropathogenic E. coli Exploit CEA to Promote Colonization of the Urogenital Tract Mucosa

    PubMed Central

    Muenzner, Petra; Kengmo Tchoupa, Arnaud; Klauser, Benedikt; Brunner, Thomas; Putze, Johannes; Dobrindt, Ulrich; Hauck, Christof R.

    2016-01-01

    Attachment to the host mucosa is a key step in bacterial pathogenesis. On the apical surface of epithelial cells, members of the human carcinoembryonic antigen (CEA) family are abundant glycoproteins involved in cell-cell adhesion and modulation of cell signaling. Interestingly, several gram-negative bacterial pathogens target these receptors by specialized adhesins. The prototype of a CEACAM-binding pathogen, Neisseria gonorrhoeae, utilizes colony opacity associated (Opa) proteins to engage CEA, as well as the CEA-related cell adhesion molecules CEACAM1 and CEACAM6 on human epithelial cells. By heterologous expression of neisserial Opa proteins in non-pathogenic E. coli we find that the Opa protein-CEA interaction is sufficient to alter gene expression, to increase integrin activity and to promote matrix adhesion of infected cervical carcinoma cells and immortalized vaginal epithelial cells in vitro. These CEA-triggered events translate in suppression of exfoliation and improved colonization of the urogenital tract by Opa protein-expressing E. coli in CEA-transgenic compared to wildtype mice. Interestingly, uropathogenic E. coli expressing an unrelated CEACAM-binding protein of the Afa/Dr adhesin family recapitulate the in vitro and in vivo phenotype. In contrast, an isogenic strain lacking the CEACAM-binding adhesin shows reduced colonization and does not suppress epithelial exfoliation. These results demonstrate that engagement of human CEACAMs by distinct bacterial adhesins is sufficient to blunt exfoliation and to promote host infection. Our findings provide novel insight into mucosal colonization by a common UPEC pathotype and help to explain why human CEACAMs are a preferred epithelial target structure for diverse gram-negative bacteria to establish a foothold on the human mucosa. PMID:27171273

  7. tkt1, located on a novel pathogenicity island, is prevalent in avian and human extraintestinal pathogenic Escherichia coli

    PubMed Central

    2012-01-01

    Background Extraintestinal pathogenic Escherichia coli are important pathogens of human and animal hosts. Some human and avian extraintestinal pathogenic E. coli are indistinguishable on the basis of diseases caused, multilocus sequence and phylogenetic typing, carriage of large virulence plasmids and traits known to be associated with extraintestinal pathogenic E. coli virulence. Results The gene tkt1 identified by a previous signature-tagged transposon mutagenesis study, was found on a 16-kb genomic island of avian pathogenic Escherichia coli (APEC) O1, the first pathogenic Escherichia coli strain whose genome has been completely sequenced. tkt1 was present in 39.6% (38/96) of pathogenic Escherichia coli strains, while only 6.25% (3/48) of E. coli from the feces of apparently healthy chickens was positive. Further, tkt1 was predominantly present in extraintestinal pathogenic E. coli belonging to the B2 phylogenetic group, as compared to extraintestinal pathogenic E. coli of other phylogenetic groups. The tkt1-containing genomic island is inserted between the metE and ysgA genes of the E. coli K12 genome. Among different extraintestinal pathogenic E. coli of the B2 phylogenetic group, 61.7% of pathogenic Escherichia coli, 80.6% of human uropathogenic E.coli and 94.1% of human neonatal meningitis-causing E. coli, respectively, harbor a complete copy of this island; whereas, only a few avian fecal E. coli strains contained the complete island. Functional analysis showed that Tkt1 confers very little transketolase activity but is involved in peptide nitrogen metabolism. Conclusion These results suggest tkt1 and its corresponding genomic island are frequently associated with avian and human ExPEC and are involved in bipeptide metabolism. PMID:22471764

  8. Adherence to Hospital Antibiotic Policy for Treatment of Escherichia coli ESBL in Urine

    PubMed Central

    Prakash, K. Gnana; Deshpande, Shreeram A.; Aravazhi, Anbu N.

    2016-01-01

    Introduction Escherichia coli are the most common uropathogen worldwide accounting for 80% of the Urinary Tract Infections (UTIs). Nosocomial infections caused by Multi-drug resistant Gram negative bacteria expressing Extended Spectrum β Lactamase enzyme, pose a serious therapeutic challenge to clinicians due to limited therapeutic options. Stringent adherence to Hospital Antibiotic Policy in treating Urinary Escherichia coli ESBLs is a borne necessity. Aim A clinical audit was undertaken in the form of a cross-sectional study to evaluate the compliance on appropriate antibiotic prescription and strict adherence to Hospital Antibiotic Policy for therapeutic management of the patients infected with urinary Escherichia coli ESBL producers. Materials and Methods A cross-sectional medical audit on adherence to treatment of Escherichia coli ESBL producers from in-patients diagnosed to have urinary tract infections for a duration of 7 months was conducted as a prospective study. Clinical data, culture and sensitivity reports of the patient diagnosed with urinary Escherichia coli ESBLs were compared with the treatment chart to ensure strict adherence to hospital antibiotic policy for appropriate therapy by physicians. Data were analysed using IBM SPSS version 20 software. Results The incidence of uncomplicated cystitis, pyelonephritis and complicated pyelonephritis cases were 65.24% (107 out of 164), 20.7% (34 out of 164) and 14.02% (23 out of 164) respectively. Resistance to individual fluoroquinolones like norfloxacin, ciprofloxacin and ofloxacin were found to be 60%, 59% and 47.5% respectively. As per hospital antibiotic policy, fluoroquinolones were prescribed in only 23% of the patients for the treatment of urinary Escherichia coli ESBLs. Conclusion Irrational utilization of antibiotics and non-adherence to antibiotic policy could have been the significant risk factors for drug resistance. Optimized antibiotic use, Microbiology laboratory support and periodic

  9. Dual ligand/receptor interactions activate urothelial defenses against uropathogenic E. coli.

    PubMed

    Liu, Yan; Mémet, Sylvie; Saban, Ricardo; Kong, Xiangpeng; Aprikian, Pavel; Sokurenko, Evgeni; Sun, Tung-Tien; Wu, Xue-Ru

    2015-11-09

    During urinary tract infection (UTI), the second most common bacterial infection, dynamic interactions take place between uropathogenic E. coli (UPEC) and host urothelial cells. While significant strides have been made in the identification of the virulence factors of UPEC, our understanding of how the urothelial cells mobilize innate defenses against the invading UPEC remains rudimentary. Here we show that mouse urothelium responds to the adhesion of type 1-fimbriated UPEC by rapidly activating the canonical NF-κB selectively in terminally differentiated, superficial (umbrella) cells. This activation depends on a dual ligand/receptor system, one between FimH adhesin and uroplakin Ia and another between lipopolysaccharide and Toll-like receptor 4. When activated, all the nuclei (up to 11) of a multinucleated umbrella cell are affected, leading to significant amplification of proinflammatory signals. Intermediate and basal cells of the urothelium undergo NF-κB activation only if the umbrella cells are detached or if the UPEC persistently express type 1-fimbriae. Inhibition of NF-κB prevents the urothelium from clearing the intracellular bacterial communities, leading to prolonged bladder colonization by UPEC. Based on these data, we propose a model of dual ligand/receptor system in innate urothelial defenses against UPEC.

  10. Characterization of Escherichia coli isolates from hospital inpatients or outpatients with urinary tract infection.

    PubMed

    Toval, Francisco; Köhler, Christian-Daniel; Vogel, Ulrich; Wagenlehner, Florian; Mellmann, Alexander; Fruth, Angelika; Schmidt, M Alexander; Karch, Helge; Bielaszewska, Martina; Dobrindt, Ulrich

    2014-02-01

    Uropathogenic Escherichia coli (UPEC) is the most common cause of community- and hospital-acquired urinary tract infections (UTIs). Isolates from uncomplicated community-acquired UTIs express a variety of virulence traits that promote the efficient colonization of the urinary tract. In contrast, nosocomial UTIs can be caused by E. coli strains that differ in their virulence traits from the community-acquired UTI isolates. UPEC virulence markers are used to distinguish these facultative extraintestinal pathogens, which belong to the intestinal flora of many healthy individuals, from intestinal pathogenic E. coli (IPEC). IPEC is a diarrheagenic pathogen with a characteristic virulence gene set that is absent in UPEC. Here, we characterized 265 isolates from patients with UTIs during inpatient or outpatient treatment at a hospital regarding their phylogenies and IPEC or UPEC virulence traits. Interestingly, 28 of these isolates (10.6%) carried typical IPEC virulence genes that are characteristic of enteroaggregative E. coli (EAEC), Shiga toxin-producing E. coli (STEC), and atypical enteropathogenic E. coli (aEPEC), although IPEC is not considered a uropathogen. Twenty-three isolates harbored the astA gene coding for the EAEC heat-stable enterotoxin 1 (EAST1), and most of them carried virulence genes that are characteristic of UPEC and/or EAEC. Our results indicate that UPEC isolates from hospital patients differ from archetypal community-acquired isolates from uncomplicated UTIs by their spectrum of virulence traits. They represent a diverse group, including EAEC, as well as other IPEC pathotypes, which in addition contain typical UPEC virulence genes. The combination of typical extraintestinal pathogenic E. coli (ExPEC) and IPEC virulence determinants in some isolates demonstrates the marked genome plasticity of E. coli and calls for a reevaluation of the strict pathotype classification of EAEC.

  11. Virulence factors in Escherichia coli urinary tract infection.

    PubMed Central

    Johnson, J R

    1991-01-01

    Uropathogenic strains of Escherichia coli are characterized by the expression of distinctive bacterial properties, products, or structures referred to as virulence factors because they help the organism overcome host defenses and colonize or invade the urinary tract. Virulence factors of recognized importance in the pathogenesis of urinary tract infection (UTI) include adhesins (P fimbriae, certain other mannose-resistant adhesins, and type 1 fimbriae), the aerobactin system, hemolysin, K capsule, and resistance to serum killing. This review summarizes the virtual explosion of information regarding the epidemiology, biochemistry, mechanisms of action, and genetic basis of these urovirulence factors that has occurred in the past decade and identifies areas in need of further study. Virulence factor expression is more common among certain genetically related groups of E. coli which constitute virulent clones within the larger E. coli population. In general, the more virulence factors a strain expresses, the more severe an infection it is able to cause. Certain virulence factors specifically favor the development of pyelonephritis, others favor cystitis, and others favor asymptomatic bacteriuria. The currently defined virulence factors clearly contribute to the virulence of wild-type strains but are usually insufficient in themselves to transform an avirulent organism into a pathogen, demonstrating that other as-yet-undefined virulence properties await discovery. Virulence factor testing is a useful epidemiological and research tool but as yet has no defined clinical role. Immunological and biochemical anti-virulence factor interventions are effective in animal models of UTI and hold promise for the prevention of UTI in humans. Images PMID:1672263

  12. Native valve Escherichia coli endocarditis following urosepsis

    PubMed Central

    Rangarajan, D.; Ramakrishnan, S.; Patro, K. C.; Devaraj, S.; Krishnamurthy, V.; Kothari, Y.; Satyaki, N.

    2013-01-01

    Gram-negative organisms are a rare cause of infective endocarditis. Escherichia coli, the most common cause of urinary tract infection and gram-negative septicemia involves endocardium rarely. In this case report, we describe infection of native mitral valve by E. coli following septicemia of urinary tract origin in a diabetic male; subsequently, he required prosthetic tissue valve replacement indicated by persistent sepsis and congestive cardiac failure. PMID:23814428

  13. Fosfomycin Resistance in Escherichia coli, Pennsylvania, USA

    PubMed Central

    Alrowais, Hind; McElheny, Christi L.; Spychala, Caressa N.; Sastry, Sangeeta; Guo, Qinglan; Butt, Adeel A.

    2015-01-01

    Fosfomycin resistance in Escherichia coli is rare in the United States. An extended-spectrum β-lactamase–producing E. coli clinical strain identified in Pennsylvania, USA, showed high-level fosfomycin resistance caused by the fosA3 gene. The IncFII plasmid carrying this gene had a structure similar to those found in China, where fosfomycin resistance is commonly described. PMID:26488485

  14. Iron induces bimodal population development by Escherichia coli.

    PubMed

    DePas, William H; Hufnagel, David A; Lee, John S; Blanco, Luz P; Bernstein, Hans C; Fisher, Steve T; James, Garth A; Stewart, Philip S; Chapman, Matthew R

    2013-02-12

    Bacterial biofilm formation is a complex developmental process involving cellular differentiation and the formation of intricate 3D structures. Here we demonstrate that exposure to ferric chloride triggers rugose biofilm formation by the uropathogenic Escherichia coli strain UTI89 and by enteric bacteria Citrobacter koseri and Salmonella enterica serovar typhimurium. Two unique and separable cellular populations emerge in iron-triggered, rugose biofilms. Bacteria at the air-biofilm interface express high levels of the biofilm regulator csgD, the cellulose activator adrA, and the curli subunit operon csgBAC. Bacteria in the interior of rugose biofilms express low levels of csgD and undetectable levels of matrix components curli and cellulose. Iron activation of rugose biofilms is linked to oxidative stress. Superoxide generation, either through addition of phenazine methosulfate or by deletion of sodA and sodB, stimulates rugose biofilm formation in the absence of high iron. Additionally, overexpression of Mn-superoxide dismutase, which can mitigate iron-derived reactive oxygen stress, decreases biofilm formation in a WT strain upon iron exposure. Not only does reactive oxygen stress promote rugose biofilm formation, but bacteria in the rugose biofilms display increased resistance to H(2)O(2) toxicity. Altogether, we demonstrate that iron and superoxide stress trigger rugose biofilm formation in UTI89. Rugose biofilm development involves the elaboration of two distinct bacterial populations and increased resistance to oxidative stress.

  15. Escherichia Coli--Key to Modern Genetics.

    ERIC Educational Resources Information Center

    Bregegere, Francois

    1982-01-01

    Mid-nineteenth century work by Mendel on plant hybrids and by Pasteur on fermentation gave birth by way of bacterial genetics to modern-day molecular biology. The bacterium Escherichia Coli has occupied a key position in genetic studies leading from early gene identification with DNA to current genetic engineering using recombinant DNA technology.…

  16. Escherichia coli in Europe: an overview.

    PubMed

    Allocati, Nerino; Masulli, Michele; Alexeyev, Mikhail F; Di Ilio, Carmine

    2013-11-25

    Escherichia coli remains one of the most frequent causes of several common bacterial infections in humans and animals. E. coli is the prominent cause of enteritis, urinary tract infection, septicaemia and other clinical infections, such as neonatal meningitis. E. coli is also prominently associated with diarrhoea in pet and farm animals. The therapeutic treatment of E. coli infections is threatened by the emergence of antimicrobial resistance. The prevalence of multidrug-resistant E. coli strains is increasing worldwide principally due to the spread of mobile genetic elements, such as plasmids. The rise of multidrug-resistant strains of E. coli also occurs in Europe. Therefore, the spread of resistance in E. coli is an increasing public health concern in European countries. This paper summarizes the current status of E. coli strains clinically relevant in European countries. Furthermore, therapeutic interventions and strategies to prevent and control infections are presented and discussed. The article also provides an overview of the current knowledge concerning promising alternative therapies against E. coli diseases.

  17. Survival of Escherichia coli in stormwater biofilters.

    PubMed

    Chandrasena, G I; Deletic, A; McCarthy, D T

    2014-04-01

    Biofilters are widely adopted in Australia for stormwater treatment, but the reported removal of common faecal indicators (such as Escherichia coli (E. coli)) varies from net removal to net leaching. Currently, the underlying mechanisms that govern the faecal microbial removal in the biofilters are poorly understood. Therefore, it is important to study retention and subsequent survival of faecal microorganisms in the biofilters under different biofilter designs and operational characteristics. The current study investigates how E. coli survival is influenced by temperature, moisture content, sunlight exposure and presence of other microorganisms in filter media and top surface sediment. Soil samples were taken from two different biofilters to investigate E. coli survival under controlled laboratory conditions. Results revealed that the presence of other microorganisms and temperature are vital stressors which govern the survival of E. coli captured either in the top surface sediment or filter media, while sunlight exposure and moisture content are important for the survival of E. coli captured in the top surface sediment compared to that of the filter media. Moreover, increased survival was found in the filter media compared to the top sediment, and sand filter media was found be more hostile than loamy sand filter media towards E. coli survival. Results also suggest that the contribution from the tested environmental stressors on E. coli survival in biofilters will be greatly affected by the seasonality and may vary from one site to another.

  18. Pathogenic Escherichia coli Found in Sewage Treatment Plants and Environmental Waters

    PubMed Central

    Anastasi, E. M.; Matthews, B.; Stratton, H. M.

    2012-01-01

    We previously demonstrated that some Escherichia coli strains with uropathogenic properties survived treatment stages of sewage treatment plants (STPs), suggesting that they may be released into the environment. We investigated the presence of such strains in the surrounding environmental waters of four STPs from which these persistent strains were isolated. In all, 264 E. coli isolates were collected from 129 receiving water sites in a 20-km radius surrounding STPs. We also included 93 E. coli strains collected from 18 animal species for comparison. Isolates were typed using a high-resolution biochemical fingerprinting method (the PhPlate system), and grouped into common (C) types. One hundred forty-seven (56%) environmental isolates were identical to strains found in STPs' final effluents. Of these, 140 (95%) carried virulence genes (VGs) associated with intestinal pathogenic E. coli (IPEC) or uropathogenic E. coli (UPEC) and were found in a variety of sites within areas sampled. Of the remaining 117 environmental strains not identical to STP strains, 105 belonged to 18 C types and 102 of them carried VGs found among IPEC or UPEC strains. These strains belonged mainly to phylogenetic groups A (A0 and A1) and B1 and to a lesser extent B22, B23, D1, and D2. Eight of 18 environmental C types, comprising 50 isolates, were also identical to bird strains. The presence of a high percentage of environmental E. coli in waters near STPs carrying VGs associated with IPEC and UPEC suggests that they may have derived from STP effluents and other nonpoint sources. PMID:22660714

  19. Pathogenic Escherichia coli found in sewage treatment plants and environmental waters.

    PubMed

    Anastasi, E M; Matthews, B; Stratton, H M; Katouli, M

    2012-08-01

    We previously demonstrated that some Escherichia coli strains with uropathogenic properties survived treatment stages of sewage treatment plants (STPs), suggesting that they may be released into the environment. We investigated the presence of such strains in the surrounding environmental waters of four STPs from which these persistent strains were isolated. In all, 264 E. coli isolates were collected from 129 receiving water sites in a 20-km radius surrounding STPs. We also included 93 E. coli strains collected from 18 animal species for comparison. Isolates were typed using a high-resolution biochemical fingerprinting method (the PhPlate system), and grouped into common (C) types. One hundred forty-seven (56%) environmental isolates were identical to strains found in STPs' final effluents. Of these, 140 (95%) carried virulence genes (VGs) associated with intestinal pathogenic E. coli (IPEC) or uropathogenic E. coli (UPEC) and were found in a variety of sites within areas sampled. Of the remaining 117 environmental strains not identical to STP strains, 105 belonged to 18 C types and 102 of them carried VGs found among IPEC or UPEC strains. These strains belonged mainly to phylogenetic groups A (A0 and A1) and B1 and to a lesser extent B2(2), B2(3), D1, and D2. Eight of 18 environmental C types, comprising 50 isolates, were also identical to bird strains. The presence of a high percentage of environmental E. coli in waters near STPs carrying VGs associated with IPEC and UPEC suggests that they may have derived from STP effluents and other nonpoint sources. PMID:22660714

  20. Heteropathogenic virulence and phylogeny reveal phased pathogenic metamorphosis in Escherichia coli O2:H6

    PubMed Central

    Bielaszewska, Martina; Schiller, Roswitha; Lammers, Lydia; Bauwens, Andreas; Fruth, Angelika; Middendorf, Barbara; Schmidt, M Alexander; Tarr, Phillip I; Dobrindt, Ulrich; Karch, Helge; Mellmann, Alexander

    2014-01-01

    Extraintestinal pathogenic and intestinal pathogenic (diarrheagenic) Escherichia coli differ phylogenetically and by virulence profiles. Classic theory teaches simple linear descent in this species, where non-pathogens acquire virulence traits and emerge as pathogens. However, diarrheagenic Shiga toxin-producing E. coli (STEC) O2:H6 not only possess and express virulence factors associated with diarrheagenic and uropathogenic E. coli but also cause diarrhea and urinary tract infections. These organisms are phylogenetically positioned between members of an intestinal pathogenic group (STEC) and extraintestinal pathogenic E. coli. STEC O2:H6 is, therefore, a ‘heteropathogen,’ and the first such hybrid virulent E. coli identified. The phylogeny of these E. coli and the repertoire of virulence traits they possess compel consideration of an alternate view of pathogen emergence, whereby one pathogroup of E. coli undergoes phased metamorphosis into another. By understanding the evolutionary mechanisms of bacterial pathogens, rational strategies for counteracting their detrimental effects on humans can be developed. Subject Categories Microbiology, Virology & Host Pathogen Interaction PMID:24413188

  1. Escherichia coli in retail processed food.

    PubMed

    Pinegar, J A; Cooke, E M

    1985-08-01

    Four thousand two hundred and forty six samples of retail processed food were examined for the presence of Escherichia coli. Overall 12% of samples contained this organism, cakes and confectionery being more frequently contaminated (28%) than meat and meat based products (9%). Contamination was more frequent in the summer months than in the colder weather and 27% of the contaminated foods contained greater than 10(3) E. coli/g. E. coli from meat and meat based products were more commonly resistant to one or more antibiotics (14%) than were confectionery strains (1%). The significance of these findings in relation to the E. coli population of the human bowel is discussed. PMID:3894508

  2. Hydrogen production by recombinant Escherichia coli strains

    PubMed Central

    Maeda, Toshinari; Sanchez‐Torres, Viviana; Wood, Thomas K.

    2012-01-01

    Summary The production of hydrogen via microbial biotechnology is an active field of research. Given its ease of manipulation, the best‐studied bacterium Escherichia coli has become a workhorse for enhanced hydrogen production through metabolic engineering, heterologous gene expression, adaptive evolution, and protein engineering. Herein, the utility of E. coli strains to produce hydrogen, via native hydrogenases or heterologous ones, is reviewed. In addition, potential strategies for increasing hydrogen production are outlined and whole‐cell systems and cell‐free systems are compared. PMID:21895995

  3. Studies of Escherichia coli Infection in Chickens

    PubMed Central

    Truscott, R. B.; Lopez-Alvarez, J.; Pettit, J. R.

    1974-01-01

    The pathogenesis of infection with Escherichia coli was studied in chickens using live O78:K80 cells and a heat-labile chick lethal toxin. The results obtained were compared with those observed in field outbreaks. The common histological findings of subepicardial edema and congestion, focal necrosis in the spleen and focal necrosis, congestion, edema and accumulation of fibrin in the liver support an active role for chick lethal toxin in the pathogenesis of E. coli disease. ImagesFig. 3.Fig. 4.Fig. 5.Fig. 6.Fig. 7. PMID:4274822

  4. ELECTRON MICROSCOPY OF PLASMOLYSIS IN ESCHERICHIA COLI.

    PubMed

    COTA-ROBLES, E H

    1963-03-01

    Cota-Robles, Eugene H. (University of California, Riverside). Electron microscopy of plasmolysis in Escherichia coli. J. Bacteriol. 85:499-503. 1963.-Escherichia coli cells plasmolyzed in 0.35 m sucrose reveal plasmolysis at one tip of a cell or in the center of dividing cells in which protoplast partition has been complete. Central plasmolysis reveals that protoplast separation can be completed before the invagination of the cell wall is complete. These studies support the concept that these cells divide by constriction. The strength of the union between cell wall and cytoplasm is not uniform around the entire cell. It is strongest along the sides of these rod-shaped cells and weakest at one tip of the single cell. Thus, a single cell generally forms one cup-shaped vacuole in which the cytoplasm has collapsed away from one tip of the cell.

  5. Pathogenesis of Afa/Dr Diffusely Adhering Escherichia coli

    PubMed Central

    Servin, Alain L.

    2005-01-01

    Over the last few years, dramatic increases in our knowledge about diffusely adhering Escherichia coli (DAEC) pathogenesis have taken place. The typical class of DAEC includes E. coli strains harboring AfaE-I, AfaE-II, AfaE-III, AfaE-V, Dr, Dr-II, F1845, and NFA-I adhesins (Afa/Dr DAEC); these strains (i) have an identical genetic organization and (ii) allow binding to human decay-accelerating factor (DAF) (Afa/DrDAF subclass) or carcinoembryonic antigen (CEA) (Afa/DrCEA subclass). The atypical class of DAEC includes two subclasses of strains; the atypical subclass 1 includes E. coli strains that express AfaE-VII, AfaE-VIII, AAF-I, AAF-II, and AAF-III adhesins, which (i) have an identical genetic organization and (ii) do not bind to human DAF, and the atypical subclass 2 includes E. coli strains that harbor Afa/Dr adhesins or others adhesins promoting diffuse adhesion, together with pathogenicity islands such as the LEE pathogenicity island (DA-EPEC). In this review, the focus is on Afa/Dr DAEC strains that have been found to be associated with urinary tract infections and with enteric infection. The review aims to provide a broad overview and update of the virulence aspects of these intriguing pathogens. Epidemiological studies, diagnostic techniques, characteristic molecular features of Afa/Dr operons, and the respective role of Afa/Dr adhesins and invasins in pathogenesis are described. Following the recognition of membrane-bound receptors, including type IV collagen, DAF, CEACAM1, CEA, and CEACAM6, by Afa/Dr adhesins, activation of signal transduction pathways leads to structural and functional injuries at brush border and junctional domains and to proinflammatory responses in polarized intestinal cells. In addition, uropathogenic Afa/Dr DAEC strains, following recognition of β1 integrin as a receptor, enter epithelial cells by a zipper-like, raft- and microtubule-dependent mechanism. Finally, the presence of other, unknown virulence factors and the way that

  6. Escherichia coli and Enterococcus faecalis are able to incorporate and enhance a pre-formed Gardnerella vaginalis biofilm.

    PubMed

    Castro, Joana; Machado, Daniela; Cerca, Nuno

    2016-04-01

    Gardnerella vaginalis is the most frequent microorganism found in bacterial vaginosis (BV), while Escherichia coli and Enterococcus faecalis are amongst the most frequent pathogens found in urinary tract infections (UTIs). This study aimed to evaluate possible interactions between UTIs pathogens and G. vaginalis using an in vitro dual-species biofilm model. Our results showed that dual-species biofilms reached significantly higher bacterial concentration than monospecies biofilms. Moreover, visualization of dual-populations species in the biofilms, using the epifluorescence microscopy, revealed that all of the urogenital pathogens coexisted with G. vaginalis. In conclusion, our work demonstrates that uropathogens can incorporate into mature BV biofilms. PMID:26782142

  7. Escherichia coli and Enterococcus faecalis are able to incorporate and enhance a pre-formed Gardnerella vaginalis biofilm.

    PubMed

    Castro, Joana; Machado, Daniela; Cerca, Nuno

    2016-04-01

    Gardnerella vaginalis is the most frequent microorganism found in bacterial vaginosis (BV), while Escherichia coli and Enterococcus faecalis are amongst the most frequent pathogens found in urinary tract infections (UTIs). This study aimed to evaluate possible interactions between UTIs pathogens and G. vaginalis using an in vitro dual-species biofilm model. Our results showed that dual-species biofilms reached significantly higher bacterial concentration than monospecies biofilms. Moreover, visualization of dual-populations species in the biofilms, using the epifluorescence microscopy, revealed that all of the urogenital pathogens coexisted with G. vaginalis. In conclusion, our work demonstrates that uropathogens can incorporate into mature BV biofilms.

  8. A Survey for Escherichia coli Virulence Factors in Asymptomatic Free-Ranging Parrots.

    PubMed

    Becker Saidenberg, André; Robaldo Guedes, Neiva Maria; Fernandes Seixas, Gláucia Helena; da Costa Allgayer, Mariangela; Pacífico de Assis, Erica; Fabio Silveira, Luis; Anne Melville, Priscilla; Benites, Nilson Roberti

    2012-01-01

    Parrots in captivity are frequently affected by Escherichia coli (E. coli) infections. The objective of this study was to collect information on the carrier state for E. coli pathotypes in asymptomatic free-ranging parrots. Cloacal swabs were collected from nestlings of Hyacinth, Lear's macaws and Blue-fronted Amazon parrots and tested by polymerase chain reaction (PCR) for virulence factors commonly found in enteropathogenic, avian pathogenic, and uropathogenic E. coli strains. In total, 44 samples were cultured and E. coli isolates were yielded, from which DNA was extracted and processed by PCR. Genes commonly found in APEC isolates from Blue-fronted Amazon parrots and Hyacinth macaws were expressed in 14 of these 44 samples. One atypical EPEC isolate was obtained from a sample from Lear's macaw. The most commonly found gene was the increased serum survival (iss) gene. This is the first report, that describes such pathotypes in asymptomatic free-living parrots. The findings of this study suggest the presence of a stable host/parasite relationship at the time of the sampling brings a new understanding to the role that E. coli plays in captive and wild parrots. Such information can be used to improve husbandry protocols as well as help conservation efforts of free-living populations.

  9. A Survey for Escherichia coli Virulence Factors in Asymptomatic Free-Ranging Parrots

    PubMed Central

    Becker Saidenberg, André; Robaldo Guedes, Neiva Maria; Fernandes Seixas, Gláucia Helena; da Costa Allgayer, Mariangela; Pacífico de Assis, Erica; Fabio Silveira, Luis; Anne Melville, Priscilla; Benites, Nilson Roberti

    2012-01-01

    Parrots in captivity are frequently affected by Escherichia coli (E. coli) infections. The objective of this study was to collect information on the carrier state for E. coli pathotypes in asymptomatic free-ranging parrots. Cloacal swabs were collected from nestlings of Hyacinth, Lear's macaws and Blue-fronted Amazon parrots and tested by polymerase chain reaction (PCR) for virulence factors commonly found in enteropathogenic, avian pathogenic, and uropathogenic E. coli strains. In total, 44 samples were cultured and E. coli isolates were yielded, from which DNA was extracted and processed by PCR. Genes commonly found in APEC isolates from Blue-fronted Amazon parrots and Hyacinth macaws were expressed in 14 of these 44 samples. One atypical EPEC isolate was obtained from a sample from Lear's macaw. The most commonly found gene was the increased serum survival (iss) gene. This is the first report, that describes such pathotypes in asymptomatic free-living parrots. The findings of this study suggest the presence of a stable host/parasite relationship at the time of the sampling brings a new understanding to the role that E. coli plays in captive and wild parrots. Such information can be used to improve husbandry protocols as well as help conservation efforts of free-living populations. PMID:23738135

  10. Characteristics of verotoxigenic Escherichia coli from pigs.

    PubMed Central

    Gannon, V P; Gyles, C L; Friendship, R W

    1988-01-01

    Porcine verotoxigenic Escherichia coli were characterized with respect to frequency of occurrence, serogroup, and association with disease, weaning, and selected properties of the bacterium. Of 668 strains of E. coli from southern Ontario pigs with enteric disease, 32 (4.8%) produced verotoxin at 10(3)-10(7) cytotoxic doses per mL of culture supernatant. Of 22 isolates which belonged to O serogroups 138, 139 and 141, 15 produced verotoxin. Among other enterotoxigenic types of E. coli, two of 57 isolates of O157:K"V17" and two of 96 isolates of O149:K91 were verotoxigenic. The remaining 13 verotoxigenic E. coli belonged to O groups 2, 107, 120, 121 and 130. An additional 21 verotoxigenic E. coli belonging to O groups 138, 139 and 141 and three to O157:K"V17" were identified in a collection of 47 E. coli recovered from weaned pigs with enteric disease. Verotoxigenic E. coli were associated with postweaning diarrhea, bloody stools, sudden death and edema disease. They were isolated at similar frequencies (14%) from healthy weaned pigs, and from weaned pigs with enteric disease. Isolation rates from neonates were low and significantly different from rates in weaned pigs. Neutralizing antibody to verotoxin was not detected in the sera of 45 pigs, which included pigs from herds with a history of edema disease. Verotoxin was not associated with production of colicin, hemolysin, or enterotoxins or with any of 23 biochemical properties of the organisms. The serological data indicate that porcine verotoxigenic E. coli are not a common source of verotoxigenic E. coli for humans. Porcine verotoxin may play a role in postweaning diarrhea and absence of detectable neutralizing antibody in serum may be an important aspect of pathogenesis. PMID:3048621

  11. Systems Metabolic Engineering of Escherichia coli.

    PubMed

    Choi, Kyeong Rok; Shin, Jae Ho; Cho, Jae Sung; Yang, Dongsoo; Lee, Sang Yup

    2016-05-01

    Systems metabolic engineering, which recently emerged as metabolic engineering integrated with systems biology, synthetic biology, and evolutionary engineering, allows engineering of microorganisms on a systemic level for the production of valuable chemicals far beyond its native capabilities. Here, we review the strategies for systems metabolic engineering and particularly its applications in Escherichia coli. First, we cover the various tools developed for genetic manipulation in E. coli to increase the production titers of desired chemicals. Next, we detail the strategies for systems metabolic engineering in E. coli, covering the engineering of the native metabolism, the expansion of metabolism with synthetic pathways, and the process engineering aspects undertaken to achieve higher production titers of desired chemicals. Finally, we examine a couple of notable products as case studies produced in E. coli strains developed by systems metabolic engineering. The large portfolio of chemical products successfully produced by engineered E. coli listed here demonstrates the sheer capacity of what can be envisioned and achieved with respect to microbial production of chemicals. Systems metabolic engineering is no longer in its infancy; it is now widely employed and is also positioned to further embrace next-generation interdisciplinary principles and innovation for its upgrade. Systems metabolic engineering will play increasingly important roles in developing industrial strains including E. coli that are capable of efficiently producing natural and nonnatural chemicals and materials from renewable nonfood biomass. PMID:27223822

  12. Interaction between Escherichia coli and lunar fines

    NASA Technical Reports Server (NTRS)

    Johansson, K. R.

    1983-01-01

    A sample of mature lunar fines (10084.151) was solubilized to a high degree (about 17 percent) by the chelating agent salicylic acid (0.01. M). The neutralized (pH adjusted to 7.0) leachate was found to inhibit the growth of Escherichia coli (ATCC 259922) in a minimial mineral salts glucose medium; however, the inhibition was somewhat less than that caused by neutralized salicylic acid alone. The presence of lunar fines in the minimal medium was highly stimulatory to growth of E. coli following an early inhibitory response. The bacterium survived less well in the lunar leachate than in distilled water, no doubt because of the salicylate. It was concluded that the sample of lunar soil tested has nutritional value to E. coli and that certain products of fermentation helped to solubilize the lunar soil.

  13. Prodigiosin - A Multifaceted Escherichia coli Antimicrobial Agent

    PubMed Central

    Zorec, Maša; Stopar, David

    2016-01-01

    Despite a considerable interest in prodigiosin, the mechanism of its antibacterial activity is still poorly understood. In this work, Escherichia coli cells were treated with prodigiosin to determine its antimicrobial effect on bacterial physiology. The effect of prodigiosin was concentration dependent. In prodigiosin treated cells above MIC value no significant DNA damage or cytoplasmic membrane disintegration was observed. The outer membrane, however, becomes leaky. Cells had severely decreased respiration activity. In prodigiosin treated cells protein and RNA synthesis were inhibited, cells were elongated but could not divide. Pre-treatment with prodigiosin improved E. coli survival rate in media containing ampicillin, kanamycin and erythromycin but not phleomycin. The results suggest that prodigiosin acts as a bacteriostatic agent in E. coli cells. If prodigiosin was diluted, cells resumed growth. The results indicate that prodigiosin has distinct mode of antibacterial action in different bacteria. PMID:27612193

  14. Thymineless Death in Escherichia coli: Strain Specificity

    PubMed Central

    Cummings, Donald J.; Mondale, Lee

    1967-01-01

    Thymineless death of various ultraviolet (UV)-sensitive strains of Escherichia coli B and K-12 was investigated. It was found that E. coli B, Bs−12, K-12 rec-21, and possibly K-12 Lon−, all sensitive to UV, were also sensitive to thymine starvation. However, other UV-sensitive strains of E. coli were found to display the typical resistant-type kinetics of thymineless death. The correlation of these results with various other cellular processes suggested that the filament-forming ability of the bacteria might be involved in the mechanism of thymineless death. It was apparent from the present results that capacity for host-cell reactivation, recombination ability, thymine dimer excision, and probably induction of a defective prophage had little to do with determining sensitivity to thymine deprivation. Images PMID:5337772

  15. Prodigiosin - A Multifaceted Escherichia coli Antimicrobial Agent.

    PubMed

    Danevčič, Tjaša; Borić Vezjak, Maja; Zorec, Maša; Stopar, David

    2016-01-01

    Despite a considerable interest in prodigiosin, the mechanism of its antibacterial activity is still poorly understood. In this work, Escherichia coli cells were treated with prodigiosin to determine its antimicrobial effect on bacterial physiology. The effect of prodigiosin was concentration dependent. In prodigiosin treated cells above MIC value no significant DNA damage or cytoplasmic membrane disintegration was observed. The outer membrane, however, becomes leaky. Cells had severely decreased respiration activity. In prodigiosin treated cells protein and RNA synthesis were inhibited, cells were elongated but could not divide. Pre-treatment with prodigiosin improved E. coli survival rate in media containing ampicillin, kanamycin and erythromycin but not phleomycin. The results suggest that prodigiosin acts as a bacteriostatic agent in E. coli cells. If prodigiosin was diluted, cells resumed growth. The results indicate that prodigiosin has distinct mode of antibacterial action in different bacteria. PMID:27612193

  16. Prodigiosin - A Multifaceted Escherichia coli Antimicrobial Agent.

    PubMed

    Danevčič, Tjaša; Borić Vezjak, Maja; Zorec, Maša; Stopar, David

    2016-01-01

    Despite a considerable interest in prodigiosin, the mechanism of its antibacterial activity is still poorly understood. In this work, Escherichia coli cells were treated with prodigiosin to determine its antimicrobial effect on bacterial physiology. The effect of prodigiosin was concentration dependent. In prodigiosin treated cells above MIC value no significant DNA damage or cytoplasmic membrane disintegration was observed. The outer membrane, however, becomes leaky. Cells had severely decreased respiration activity. In prodigiosin treated cells protein and RNA synthesis were inhibited, cells were elongated but could not divide. Pre-treatment with prodigiosin improved E. coli survival rate in media containing ampicillin, kanamycin and erythromycin but not phleomycin. The results suggest that prodigiosin acts as a bacteriostatic agent in E. coli cells. If prodigiosin was diluted, cells resumed growth. The results indicate that prodigiosin has distinct mode of antibacterial action in different bacteria.

  17. Prevalence of Avian-Pathogenic Escherichia coli Strain O1 Genomic Islands among Extraintestinal and Commensal E. coli Isolates

    PubMed Central

    Johnson, Timothy J.; Wannemuehler, Yvonne; Kariyawasam, Subhashinie; Johnson, James R.; Logue, Catherine M.

    2012-01-01

    Escherichia coli strains that cause disease outside the intestine are known as extraintestinal pathogenic E. coli (ExPEC) and include pathogens of humans and animals. Previously, the genome of avian-pathogenic E. coli (APEC) O1:K1:H7 strain O1, from ST95, was sequenced and compared to those of several other E. coli strains, identifying 43 genomic islands. Here, the genomic islands of APEC O1 were compared to those of other sequenced E. coli strains, and the distribution of 81 genes belonging to 12 APEC O1 genomic islands among 828 human and avian ExPEC and commensal E. coli isolates was determined. Multiple islands were highly prevalent among isolates belonging to the O1 and O18 serogroups within phylogenetic group B2, which are implicated in human neonatal meningitis. Because of the extensive genomic similarities between APEC O1 and other human ExPEC strains belonging to the ST95 phylogenetic lineage, its ability to cause disease in a rat model of sepsis and meningitis was assessed. Unlike other ST95 lineage strains, APEC O1 was unable to cause bacteremia or meningitis in the neonatal rat model and was significantly less virulent than uropathogenic E. coli (UPEC) CFT073 in a mouse sepsis model, despite carrying multiple neonatal meningitis E. coli (NMEC) virulence factors and belonging to the ST95 phylogenetic lineage. These results suggest that host adaptation or genome modifications have occurred either in APEC O1 or in highly virulent ExPEC isolates, resulting in differences in pathogenicity. Overall, the genomic islands examined provide targets for further discrimination of the different ExPEC subpathotypes, serogroups, phylogenetic types, and sequence types. PMID:22467781

  18. Biodegradation of Aromatic Compounds by Escherichia coli

    PubMed Central

    Díaz, Eduardo; Ferrández, Abel; Prieto, María A.; García, José L.

    2001-01-01

    Although Escherichia coli has long been recognized as the best-understood living organism, little was known about its abilities to use aromatic compounds as sole carbon and energy sources. This review gives an extensive overview of the current knowledge of the catabolism of aromatic compounds by E. coli. After giving a general overview of the aromatic compounds that E. coli strains encounter and mineralize in the different habitats that they colonize, we provide an up-to-date status report on the genes and proteins involved in the catabolism of such compounds, namely, several aromatic acids (phenylacetic acid, 3- and 4-hydroxyphenylacetic acid, phenylpropionic acid, 3-hydroxyphenylpropionic acid, and 3-hydroxycinnamic acid) and amines (phenylethylamine, tyramine, and dopamine). Other enzymatic activities acting on aromatic compounds in E. coli are also reviewed and evaluated. The review also reflects the present impact of genomic research and how the analysis of the whole E. coli genome reveals novel aromatic catabolic functions. Moreover, evolutionary considerations derived from sequence comparisons between the aromatic catabolic clusters of E. coli and homologous clusters from an increasing number of bacteria are also discussed. The recent progress in the understanding of the fundamentals that govern the degradation of aromatic compounds in E. coli makes this bacterium a very useful model system to decipher biochemical, genetic, evolutionary, and ecological aspects of the catabolism of such compounds. In the last part of the review, we discuss strategies and concepts to metabolically engineer E. coli to suit specific needs for biodegradation and biotransformation of aromatics and we provide several examples based on selected studies. Finally, conclusions derived from this review may serve as a lead for future research and applications. PMID:11729263

  19. Inhibition of biofilm development of uropathogens by curcumin - an anti-quorum sensing agent from Curcuma longa.

    PubMed

    Packiavathy, Issac Abraham Sybiya Vasantha; Priya, Selvam; Pandian, Shunmugiah Karutha; Ravi, Arumugam Veera

    2014-04-01

    Urinary tract infection is caused primarily by the quorum sensing (QS)-dependent biofilm forming ability of uropathogens. In the present investigation, an anti-quorum sensing (anti-QS) agent curcumin from Curcuma longa (turmeric) was shown to inhibit the biofilm formation of uropathogens, such as Escherichia coli, Pseudomonas aeruginosa PAO1, Proteus mirabilis and Serratia marcescens, possibly by interfering with their QS systems. The antibiofilm potential of curcumin on uropathogens as well as its efficacy in disturbing the mature biofilms was examined under light microscope and confocal laser scanning microscope. The treatment with curcumin was also found to attenuate the QS-dependent factors, such as exopolysaccharide production, alginate production, swimming and swarming motility of uropathogens. Furthermore, it was documented that curcumin enhanced the susceptibility of a marker strain and uropathogens to conventional antibiotics. PMID:24262582

  20. Inhibition of biofilm development of uropathogens by curcumin - an anti-quorum sensing agent from Curcuma longa.

    PubMed

    Packiavathy, Issac Abraham Sybiya Vasantha; Priya, Selvam; Pandian, Shunmugiah Karutha; Ravi, Arumugam Veera

    2014-04-01

    Urinary tract infection is caused primarily by the quorum sensing (QS)-dependent biofilm forming ability of uropathogens. In the present investigation, an anti-quorum sensing (anti-QS) agent curcumin from Curcuma longa (turmeric) was shown to inhibit the biofilm formation of uropathogens, such as Escherichia coli, Pseudomonas aeruginosa PAO1, Proteus mirabilis and Serratia marcescens, possibly by interfering with their QS systems. The antibiofilm potential of curcumin on uropathogens as well as its efficacy in disturbing the mature biofilms was examined under light microscope and confocal laser scanning microscope. The treatment with curcumin was also found to attenuate the QS-dependent factors, such as exopolysaccharide production, alginate production, swimming and swarming motility of uropathogens. Furthermore, it was documented that curcumin enhanced the susceptibility of a marker strain and uropathogens to conventional antibiotics.

  1. Inhibition and Reversal of Microbial Attachment by an Antibody with Parasteric Activity against the FimH Adhesin of Uropathogenic E. coli

    PubMed Central

    Friend, Della; Jalan, Aachal; Gupta, Shivani; Interlandi, Gianluca; Liu, Yan; Tchesnokova, Veronika; Rodriguez, Victoria B.; Sumida, John P.; Strong, Roland K.; Wu, Xue-Ru; Thomas, Wendy E.; Sokurenko, Evgeni V.

    2015-01-01

    Attachment proteins from the surface of eukaryotic cells, bacteria and viruses are critical receptors in cell adhesion or signaling and are primary targets for the development of vaccines and therapeutic antibodies. It is proposed that the ligand-binding pocket in receptor proteins can shift between inactive and active conformations with weak and strong ligand-binding capability, respectively. Here, using monoclonal antibodies against a vaccine target protein - fimbrial adhesin FimH of uropathogenic Escherichia coli, we demonstrate that unusually strong receptor inhibition can be achieved by antibody that binds within the binding pocket and displaces the ligand in a non-competitive way. The non-competitive antibody binds to a loop that interacts with the ligand in the active conformation of the pocket but is shifted away from ligand in the inactive conformation. We refer to this as a parasteric inhibition, where the inhibitor binds adjacent to the ligand in the binding pocket. We showed that the receptor-blocking mechanism of parasteric antibody differs from that of orthosteric inhibition, where the inhibitor replaces the ligand or allosteric inhibition where the inhibitor binds at a site distant from the ligand, and is very potent in blocking bacterial adhesion, dissolving surface-adherent biofilms and protecting mice from urinary bladder infection. PMID:25974133

  2. An electrochemical immunosensor for efficient detection of uropathogenic E. coli based on thionine dye immobilized chitosan/functionalized-MWCNT modified electrode.

    PubMed

    Gayathri, Chandran Hema; Mayuri, Pinapeddavari; Sankaran, Krishnan; Kumar, Annamalai Senthil

    2016-08-15

    Uropathogenic Escherichia coli (UPEC) is the major cause of 150 million Urinary Tract Infections (UTI) reported annually world-wide. High prevalence of multi-drug-resistance makes it dangerous and difficult to cure. Therefore simple, quick and early diagnostic tools are essential for effective treatment and control. We report an electrochemical immunosensor based on thionine dye (Th) immobilized on functionalized-multiwalled carbon nanotube+chitosan composite coated on glassy carbon electrode (GCE/f-MWCNT-Chit@Th) for quick and sensitive detection of UPEC in aqueous solution. This immunosensor was constructed by sequential immobilization of UPEC, bovine serum albumin, primary antibody and Horse Radish Peroxidase (HRP) tagged secondary antibody on the surface of GCE/f-MWCNT-Chit@Th. When analyzed using 2.5mM of hydrogen peroxide reduction reaction using cyclic voltammetry in phosphate buffer, pH 7.0, the immunosensor showed excellent linearity in a range of 10(2)-10(9)cfu of UPEC mL(-1) with a current sensitivity of 7.162μA {log(cfumL(-1))}(-1). The specificity of this immunosensor was tested using other UTI and non-UTI bacteria, Staphylococcus, Klebsiella, Proteus and Shigella. The clinical applicability of the immunosensor was also successfully tested directly in UPEC spiked urine samples (simulated sample). PMID:27040944

  3. Activity of Fosfomycin against Extended-Spectrum-β-Lactamase-Producing Uropathogens in Patients in the Community and Hospitalized Patients

    PubMed Central

    Strymish, Judith; Weir, Susan; Berg, Gretchen; Brecher, Stephen; Gupta, Kalpana

    2015-01-01

    Few oral antibiotics exist for the empirical treatment of extended-spectrum β-lactamase (ESBL) urinary tract infections (UTI). In this study, we sought to determine the activity of fosfomycin against ESBL-producing uropathogens from patients at 3 Veterans Affairs (VA) facilities between 2010 and 2013. Among the ESBL uropathogens, 19.9% were fosfomycin resistant. Klebsiella species were more likely than Escherichia coli to be resistant (46% versus 4%; P < 0.001). Fosfomycin remains active against a majority of the ESBL uropathogens, although resistance among Klebsiella spp. was higher than that in previous reports. PMID:26596940

  4. Logarithmic Sensing in Escherichia coli Bacterial Chemotaxis

    PubMed Central

    Kalinin, Yevgeniy V.; Jiang, Lili; Tu, Yuhai; Wu, Mingming

    2009-01-01

    We studied the response of swimming Escherichia coli (E. coli) bacteria in a comprehensive set of well-controlled chemical concentration gradients using a newly developed microfluidic device and cell tracking imaging technique. In parallel, we carried out a multi-scale theoretical modeling of bacterial chemotaxis taking into account the relevant internal signaling pathway dynamics, and predicted bacterial chemotactic responses at the cellular level. By measuring the E. coli cell density profiles across the microfluidic channel at various spatial gradients of ligand concentration grad[L] and the average ligand concentration [L]¯near the peak chemotactic response region, we demonstrated unambiguously in both experiments and model simulation that the mean chemotactic drift velocity of E. coli cells increased monotonically with grad [L]/[L]¯ or ∼grad(log[L])—that is E. coli cells sense the spatial gradient of the logarithmic ligand concentration. The exact range of the log-sensing regime was determined. The agreements between the experiments and the multi-scale model simulation verify the validity of the theoretical model, and revealed that the key microscopic mechanism for logarithmic sensing in bacterial chemotaxis is the adaptation kinetics, in contrast to explanations based directly on ligand occupancy. PMID:19289068

  5. Profiling of Escherichia coli Chromosome database.

    PubMed

    Yamazaki, Yukiko; Niki, Hironori; Kato, Jun-ichi

    2008-01-01

    The Profiling of Escherichia coli Chromosome (PEC) database (http://www.shigen.nig.ac.jp/ecoli/pec/) is designed to allow E. coli researchers to efficiently access information from functional genomics studies. The database contains two principal types of data: gene essentiality and a large collection of E. coli genetic research resources. The essentiality data are based on data compilation from published single-gene essentiality studies and on cell growth studies of large-deletion mutants. Using the circular and linear viewers for both whole genomes and the minimal genome, users can not only gain an overview of the genome structure but also retrieve information on contigs, gene products, mutants, deletions, and so forth. In particular, genome-wide exhaustive mutants are an essential resource for studying E. coli gene functions. Although the genomic database was constructed independently from the genetic resources database, users may seamlessly access both types of data. In addition to these data, the PEC database also provides a summary of homologous genes of other bacterial genomes and of protein structure information, with a comprehensive interface. The PEC is thus a convenient and useful platform for contemporary E. coli researchers. PMID:18392982

  6. Preventing urinary tract infection: progress toward an effective Escherichia coli vaccine

    PubMed Central

    Brumbaugh, Ariel R; Mobley, Harry LT

    2012-01-01

    Uncomplicated urinary tract infections (UTIs) are common, with nearly half of all women experiencing at least one UTI in their lifetime. This high frequency of infection results in huge annual economic costs, decreased workforce productivity and high patient morbidity. At least 80% of these infections are caused by uropathogenic Escherichia coli (UPEC). UPEC can reside side by side with commensal strains in the gastrointestinal tract and gain access to the bladder via colonization of the urethra. Antibiotics represent the current standard treatment for UTI; however, even after treatment, patients frequently suffer from recurrent infection with the same or different strains. In addition, successful long-term treatment has been complicated by a rise in both the number of antibiotic-resistant strains and the prevalence of antibiotic-resistance mechanisms. As a result, preventative approaches to UTI, such as vaccination, have been sought. This review summarizes recent advances in UPEC vaccine development and outlines future directions for the field. PMID:22873125

  7. ELECTROPHORETIC MOBILITIES OF ESCHERICHIA COLI 0157:H7 AND WILD-TYPE ESCHERICHIA COLI STRAINS

    EPA Science Inventory

    The electrophoretic mobility (EPM) of a number of human-virulent and "wild-type" Escherichia coli strains in phosphate buffered water was measured. The impact of pH, ionic strength, cation type (valence) and concentration, and bacterial strain on the EPM was investigated. Resul...

  8. Characterization of P fimbriae on O1, O7, O75, rough, and nontypable strains of Escherichia coli.

    PubMed Central

    Pere, A; Selander, R K; Korhonen, T K

    1988-01-01

    P fimbriae of 37 uropathogenic Escherichia coli O1:K1, O7:K1, O22, O75, rough:K1, and nontypable strains were characterized by immunoprecipitation with 14 fimbria-specific rabbit antisera. The fimbrial composition of these strains, as reflected by the apparent molecular weights of the fimbrial peptides, was correlated with the O serogroup of the strains, but serological cross-reactivity of P fimbriae of different E. coli serogroups was frequently observed. The genetic clonal relationships of the strains were analyzed by determining the electrophoretic types, based on 18 chromosomally encoded enzymes. Among the O1:K1 strains, the same P-fimbrial variants occurred on strains that were either closely related or very distinct in their electrophoretic types, indicating that the P fimbriae have evolved in association with the O and K antigens. In contrast, certain O7:K1 and R:K1 strains as well as some O22 and O75 strains were genotypically identical and shared similar P-fimbrial variants, which differed serologically from those of other E. coli serogroups. Our results show that, despite the structural variability seen in electrophoretic analysis of P fimbriae of different serogroups, many P-fimbrial variants share common antigenic determinants that are recognized by rabbit antisera. Based on immunoprecipitation analyses, three anti-P-fimbria sera have now been identified that react with P fimbriae of 82 of 84 uropathogenic E. coli strains characterized in Finland. Images PMID:2895742

  9. Towards a vaccine against Escherichia coli-associated urinary tract infections.

    PubMed

    Serino, Laura; Moriel, Danilo Gomes; Rappuoli, Rino; Pizza, Mariagrazia

    2010-03-01

    Evaluation of: Alteri CJ, Hagan EC, Sivick KE, Smith SN, Mobley HLT: Mucosal immunization with iron receptor antigens protects against urinary tract infections. PLoS Pathog. 5(9), E1000586 (2009). Urinary tract infection is one of the most common infections in humans. The eradication of uropathogenic Escherichia coli-mediated urinary tract infections has still not been achieved and no effective licensed vaccines are currently available. To overcome the limitations of previous approaches in developing an efficacious vaccine, Alteri et al., through a functional genomic approach, identified six novel vaccine candidates shown to be protective against urinary tract infection in a mouse model. The six proteins all belong to the class of outer membrane iron receptors, are upregulated in iron-restricted conditions and were demonstrated to induce, upon mucosal vaccination, antigen-specific antibodies and cytokine responses, which correlated with protection in a mouse model of urinary tract infection. Therefore, for the first time, antigens that were previously recognized as necessary for bacterial pathogenesis, being involved in iron acquisition in an iron-limited environment such as the urinary tract, are now proposed as potential candidates for the development of a vaccine against uropathogenic strain-associated urinary tract infections.

  10. [Recombinant protein production in Escherichia coli].

    PubMed

    Nuc, Przemysław; Nuc, Katarzyna

    2006-01-01

    Growing needs for efficient recombinant production pose new challenges; starting from cell growth optimization under overexpression conditions, improving vectors, gene and protein sequence to suit them to protein biosynthesis machinery of the host, through extending the knowledge of protein folding, fusion protein construction, and coexpression systems, to improvements in protein purification and renaturation technologies. Hitherto Escherichia coli is the most defined and the cheapest protein biosynthesis system. With its wealth of available mutants tested is the best suited to economically test new gene constructs and to scale up the recombinant protein production.

  11. Enteropathogenic Escherichia coli: foe or innocent bystander?

    PubMed

    Hu, J; Torres, A G

    2015-08-01

    Enteropathogenic Escherichia coli (EPEC) remain one the most important pathogens infecting children and they are one of the main causes of persistent diarrhoea worldwide. Historically, typical EPEC (tEPEC), defined as those isolates with the attaching and effacement (A/E) genotype (eae(+)), which possess bfpA(+) and lack the stx(-) genes are found strongly associated with diarrhoeal cases. However, occurrence of atypical EPEC (aEPEC; eae(+)bfpA(-)stx(-)) in diarrhoeal and asymptomatic hosts has made investigators question the role of these pathogens in human disease. Current epidemiological data are helping to answer the question of whether EPEC is mainly a foe or an innocent bystander during infection.

  12. Enterotoxigenic Escherichia coli: Orchestrated host engagement.

    PubMed

    Fleckenstein, James M; Munson, George M; Rasko, David A

    2013-01-01

    The enterotoxigenic Escherichia coli are a pervasive cause of serious diarrheal illness in developing countries. Presently, there is no vaccine to prevent these infections, and many features of the basic pathogenesis of these organisms remain poorly understood. Until very recently most pathogenesis studies had focused almost exclusively on a small subset of known "classical" virulence genes, namely fimbrial colonization factors and the heat-labile (LT) and heat stable (ST) enterotoxins. However, recent investigations of pathogen-host interactions reveal a surprisingly complex and intricately orchestrated engagement involving the interplay of classical and "novel" virulence genes, as well as participation of genes highly conserved in the E. coli species. These studies may inform further rational approaches to vaccine development for these important pathogens. PMID:23892244

  13. Escherichia coli growth under modeled reduced gravity

    NASA Technical Reports Server (NTRS)

    Baker, Paul W.; Meyer, Michelle L.; Leff, Laura G.

    2004-01-01

    Bacteria exhibit varying responses to modeled reduced gravity that can be simulated by clino-rotation. When Escherichia coli was subjected to different rotation speeds during clino-rotation, significant differences between modeled reduced gravity and normal gravity controls were observed only at higher speeds (30-50 rpm). There was no apparent affect of removing samples on the results obtained. When E. coli was grown in minimal medium (at 40 rpm), cell size was not affected by modeled reduced gravity and there were few differences in cell numbers. However, in higher nutrient conditions (i.e., dilute nutrient broth), total cell numbers were higher and cells were smaller under reduced gravity compared to normal gravity controls. Overall, the responses to modeled reduced gravity varied with nutrient conditions; larger surface to volume ratios may help compensate for the zone of nutrient depletion around the cells under modeled reduced gravity.

  14. Engineering the Escherichia coli Fermentative Metabolism

    NASA Astrophysics Data System (ADS)

    Orencio-Trejo, M.; Utrilla, J.; Fernández-Sandoval, M. T.; Huerta-Beristain, G.; Gosset, G.; Martinez, A.

    Fermentative metabolism constitutes a fundamental cellular capacity for industrial biocatalysis. Escherichia coli is an important microorganism in the field of metabolic engineering for its well-known molecular characteristics and its rapid growth. It can adapt to different growth conditions and is able to grow in the presence or absence of oxygen. Through the use of metabolic pathway engineering and bioprocessing techniques, it is possible to explore the fundamental cellular properties and to exploit its capacity to be applied as industrial biocatalysts to produce a wide array of chemicals. The objective of this chapter is to review the metabolic engineering efforts carried out with E. coli by manipulating the central carbon metabolism and fermentative pathways to obtain strains that produce metabolites with high titers, such as ethanol, alanine, lactate and succinate.

  15. Role of special pathogenicity versus prevalence theory in pathogenesis of acute cystitis caused by Escherichia coli.

    PubMed

    Srivastava, Richa; Agarwal, Jyotsna; Srivastava, Sugandha; Mishra, Bharti

    2014-08-01

    Escherichia coli is the most common pathogen causing acute cystitis in sexually active women. Human faeces are generally considered the primary reservoir for infection and the faecal-perineal-urethral pathway is the accepted route of infection. Two theories have been proposed for the pathogenesis of acute cystitis: (1) special pathogenicity, where uropathogenic E. coli (UPEC) encoding special virulence factors causes infection; and (2) prevalence, wherein ordinary faecal E. coli causes infection by simple mass action. The aim of this study was to compare concurrent urinary E. coli isolates from women with acute cystitis with their own dominant faecal, vaginal E. coli isolates; thus, these patients served as their own control. E. coli isolates from 80 women were analysed by phylotyping, virulence profiling (for 15 putative virulence genes) and enterobacterial repetitive intergenic consensus (ERIC) PCR. A virulence score was calculated for each isolate based on the number of virulence genes detected. Four host ecological groups of E. coli were created on the basis of ERIC PCR: group UVF, where vaginal and faecal isolates yielded the infecting urine clone; group UV, where only vaginal isolates yielded the infecting urine clone; group UF, where faecal isolates yielded the infecting urine clone; and group U, where the infecting urine clone was distinct. In the majority of cases the infecting E. coli clone from urine was also the dominant faecal clone (56.3%; groups UVF and UF possessing high virulence scores of 4.6 and 3.9, respectively), indicating that both mechanisms play a role in pathogenesis. Non-dominant yet virulent faecal clones or an external source of E. coli seems a possibility in the UV group (13.7%, VF score 4.8). In 30% of patients (U group) the infecting urine clone was non-dominant and possessed a low virulence score (2.7); suggesting a possible role for host factors in establishing infection.

  16. Escherichia coli as a bioreporter in ecotoxicology.

    PubMed

    Robbens, Johan; Dardenne, Freddy; Devriese, Lisa; De Coen, Wim; Blust, Ronny

    2010-11-01

    Ecotoxicological assessment relies to a large extent on the information gathered with surrogate species and the extrapolation of test results across species and different levels of biological organisation. Bacteria have long been used as a bioreporter for genotoxic testing and general toxicity. Today, it is clear that bacteria have the potential for screening of other toxicological endpoints. Escherichia coli has been studied for years; in-depth knowledge of its biochemistry and genetics makes it the most proficient prokaryote for the development of new toxicological assays. Several assays have been designed with E. coli as a bioreporter, and the recent trend to develop novel, better advanced reporters makes bioreporter development one of the most dynamic in ecotoxicology. Based on in-depth knowledge of E. coli, new assays are being developed or existing ones redesigned, thanks to the availability of new reporter genes and new or improved substrates. The technological evolution towards easier and more sensitive detection of different gene products is another important aspect. Often, this requires the redesign of the bacterium to make it compatible with the novel measuring tests. Recent advances in surface chemistry and nanoelectronics open the perspective for advanced reporter based on novel measuring platforms and with an online potential. In this article, we will discuss the use of E. coli-based bioreporters in ecotoxicological applications as well as some innovative sensors awaited for the future.

  17. Escherichia coli O157:H7.

    PubMed

    Mead, P S; Griffin, P M

    1998-10-10

    Escherichia coli O157 was first identified as a human pathogen in 1982. One of several Shiga toxin-producing serotypes known to cause human illness, the organism probably evolved through horizontal acquisition of genes for Shiga toxins and other virulence factors. E. coli O157 is found regularly in the faeces of healthy cattle, and is transmitted to humans through contaminated food, water, and direct contact with infected people or animals. Human infection is associated with a wide range of clinical illness, including asymptomatic shedding, non-bloody diarrhoea, haemorrhagic colitis, haemolytic uraemic syndrome, and death. Since laboratory practices vary, physicians need to know whether laboratories in their area routinely test for E. coli O157 in stool specimens. Treatment with antimicrobial agents remains controversial: some studies suggest that treatment may precipitate haemolytic uraemic syndrome, and other studies suggest no effect or even a protective effect. Physicians can help to prevent E. coli O157 infections by counselling patients about the hazards of consuming undercooked ground meat or unpasteurised milk products and juices, and about the importance of handwashing to prevent the spread of diarrhoeal illness, and by informing public-health authorities when they see unusual numbers of cases of bloody diarrhoea or haemolytic uraemic syndrome.

  18. Engineering Escherichia coli for methanol conversion.

    PubMed

    Müller, Jonas E N; Meyer, Fabian; Litsanov, Boris; Kiefer, Patrick; Potthoff, Eva; Heux, Stéphanie; Quax, Wim J; Wendisch, Volker F; Brautaset, Trygve; Portais, Jean-Charles; Vorholt, Julia A

    2015-03-01

    Methylotrophic bacteria utilize methanol and other reduced one-carbon compounds as their sole source of carbon and energy. For this purpose, these bacteria evolved a number of specialized enzymes and pathways. Here, we used a synthetic biology approach to select and introduce a set of "methylotrophy genes" into Escherichia coli based on in silico considerations and flux balance analysis to enable methanol dissimilation and assimilation. We determined that the most promising approach allowing the utilization of methanol was the implementation of NAD-dependent methanol dehydrogenase and the establishment of the ribulose monophosphate cycle by expressing the genes for hexulose-6-phosphate synthase (Hps) and 6-phospho-3-hexuloisomerase (Phi). To test for the best-performing enzymes in the heterologous host, a number of enzyme candidates from different donor organisms were selected and systematically analyzed for their in vitro and in vivo activities in E. coli. Among these, Mdh2, Hps and Phi originating from Bacillus methanolicus were found to be the most effective. Labeling experiments using (13)C methanol with E. coli producing these enzymes showed up to 40% incorporation of methanol into central metabolites. The presence of the endogenous glutathione-dependent formaldehyde oxidation pathway of E. coli did not adversely affect the methanol conversion rate. Taken together, the results of this study represent a major advancement towards establishing synthetic methylotrophs by gene transfer.

  19. Transport proteins promoting Escherichia coli pathogenesis

    PubMed Central

    Tang, Fengyi; Saier, Milton H.

    2014-01-01

    Escherichia coli is a genetically diverse species infecting hundreds of millions of people worldwide annually. We examined seven well-characterized E. coli pathogens causing urinary tract infections, gastroenteritis, pyelonephritis and haemorrhagic colitis. Their transport proteins were identified and compared with each other and a non-pathogenic E. coli K12 strain to identify transport proteins related to pathogenesis. Each pathogen possesses a unique set of protein secretion systems for export to the cell surface or for injecting effector proteins into host cells. Pathogens have increased numbers of iron siderophore receptors and ABC iron uptake transporters, but the numbers and types of low-affinity secondary iron carriers were uniform in all strains. The presence of outer membrane iron complex receptors and high-affinity ABC iron uptake systems correlated, suggesting co-evolution. Each pathovar encodes a different set of pore-forming toxins and virulence-related outer membrane proteins lacking in K12. Intracellular pathogens proved to have a characteristically distinctive set of nutrient uptake porters, different from those of extracellular pathogens. The results presented in this report provide information about transport systems relevant to various types of E. coli pathogenesis that can be exploited in future basic and applied studies. PMID:24747185

  20. Aerobactin and other virulence factor genes among strains of Escherichia coli causing urosepsis: association with patient characteristics.

    PubMed

    Johnson, J R; Moseley, S L; Roberts, P L; Stamm, W E

    1988-02-01

    To assess the role of aerobactin as a virulence factor among uropathogenic Escherichia coli, we determined the prevalence, location, and phenotypic expression of aerobactin determinants among 58 E. coli strains causing bacteremic urinary tract infections. We correlated the presence of the aerobactin system with antimicrobial-agent resistance, the presence and phenotypic expression of other uropathogenic virulence factor determinants (P fimbriae, hemolysin, and type 1 fimbriae), and characteristics of patients. Colony and Southern hybridization of total and plasmid DNA with DNA probes for each virulence factor showed that aerobactin determinants were present in 78% of the strains and were plasmid associated in 21%, whereas P fimbria, hemolysin, and type 1 fimbria determinants were present in 74, 43, and 98% of the strains, respectively, and were always chromosomal. Chromosomal aerobactin, P fimbria, and hemolysin determinants occurred together on the chromosome more often in strains from patients without predisposing urological or medical conditions (P = 0.04). Strains with plasmid-encoded aerobactin lacked determinants for P fimbriae (P = 0.004) and hemolysin (P = 0.0004), were resistant to multiple antimicrobial agents (P = 0.0001), and were found only in compromised patients. Mating experiments demonstrated that some aerobactin plasmids also encoded antimicrobial-agent resistance. These findings suggest that the determinants for aerobactin, P fimbriae, and hemolysin are conserved on the chromosome of the antimicrobial-agent-susceptible uropathogenic strains of E. coli which invade noncompromised patients. In contrast, these chromosomal virulence factors are often absent from E. coli strains causing urosepsis in compromised hosts; these strains may acquire plasmid aerobactin in conjunction with antimicrobial-agent resistance genes.

  1. GLYCOLATE METABOLISM IN ESCHERICHIA COLI1

    PubMed Central

    Hansen, Robert W.; Hayashi, James A.

    1962-01-01

    Hansen, Robert W. (University of Illinois College of Medicine, Chicago) and James A. Hayashi. Glycolate metabolism in Escherichia coli. J. Bacteriol. 83:679–687. 1962.—This study of glycolate-adapted Escherichia coli indicates that the most probable route for utilization of the substrate includes glyceric acid, 3-phosphoglyceric acid, and the tricarboxylic acid cycle. A glyceric acid dehydrogenase, which reduces tartronic semialdehyde to glycerate in the presence of reduced diphosphopyridine nucleotide, and a kinase, which catalyzes the formation of 3-phosphoglycerate from glyceric acid and adenosine triphosphate, were shown to be present. Carbon recoveries in growing cultures and manometric data obtained with resting cells showed the complete oxidation of glycolate to carbon dioxide. Measurements of the oxidation of tricarboxylic acid cycle intermediates indicated that these compounds are oxidized without lag and at a rate commensurate with the rate of glycolate oxidation. Assays of the enzymes characteristic of known pathways of terminal oxidation, such as isocitratase, malate synthetase, isocitric dehydrogenase, and condensing enzyme, provided further evidence for an operating tricarboxylic acid cycle. A postulated pathway for the utilization of glycolic acid is as follows: glycolate → glycerate → 3-phosphoglycerate → pyruvate → tricarboxylic acid cycle. PMID:13904441

  2. Production of glycoprotein vaccines in Escherichia coli

    PubMed Central

    2010-01-01

    Background Conjugate vaccines in which polysaccharide antigens are covalently linked to carrier proteins belong to the most effective and safest vaccines against bacterial pathogens. State-of-the art production of conjugate vaccines using chemical methods is a laborious, multi-step process. In vivo enzymatic coupling using the general glycosylation pathway of Campylobacter jejuni in recombinant Escherichia coli has been suggested as a simpler method for producing conjugate vaccines. In this study we describe the in vivo biosynthesis of two novel conjugate vaccine candidates against Shigella dysenteriae type 1, an important bacterial pathogen causing severe gastro-intestinal disease states mainly in developing countries. Results Two different periplasmic carrier proteins, AcrA from C. jejuni and a toxoid form of Pseudomonas aeruginosa exotoxin were glycosylated with Shigella O antigens in E. coli. Starting from shake flask cultivation in standard complex medium a lab-scale fed-batch process was developed for glycoconjugate production. It was found that efficiency of glycosylation but not carrier protein expression was highly susceptible to the physiological state at induction. After induction glycoconjugates generally appeared later than unglycosylated carrier protein, suggesting that glycosylation was the rate-limiting step for synthesis of conjugate vaccines in E. coli. Glycoconjugate synthesis, in particular expression of oligosaccharyltransferase PglB, strongly inhibited growth of E. coli cells after induction, making it necessary to separate biomass growth and recombinant protein expression phases. With a simple pulse and linear feed strategy and the use of semi-defined glycerol medium, volumetric glycoconjugate yield was increased 30 to 50-fold. Conclusions The presented data demonstrate that glycosylated proteins can be produced in recombinant E. coli at a larger scale. The described methodologies constitute an important step towards cost-effective in vivo

  3. Type 1 fimbrial expression enhances Escherichia coli virulence for the urinary tract.

    PubMed Central

    Connell, I; Agace, W; Klemm, P; Schembri, M; Mărild, S; Svanborg, C

    1996-01-01

    Type 1 fimbriae are adhesion organelles expressed by many Gram-negative bacteria. They facilitate adherence to mucosal surfaces and inflammatory cells in vitro, but their contribution to virulence has not been defined. This study presents evidence that type 1 fimbriae increase the virulence of Escherichia coli for the urinary tract by promoting bacterial persistence and enhancing the inflammatory response to infection. In a clinical study, we observed that disease severity was greater in children infected with E. coli O1:K1:H7 isolates expressing type 1 fimbriae than in those infected with type 1 negative isolates of the same serotype. The E. coli O1:K1:H7 isolates had the same electrophoretic type, were hemolysin-negative, expressed P fimbriae, and carried the fim DNA sequences. When tested in a mouse urinary tract infection model, the type 1-positive E. coli O1:K1:H7 isolates survived in higher numbers, and induced a greater neutrophil influx into the urine, than O1:K1:H7 type 1-negative isolates. To confirm a role of type 1 fimbriae, a fimH null mutant (CN1016) was constructed from an O1:K1:H7 type 1-positive parent. E. coli CN1016 had reduced survival and inflammatogenicity in the mouse urinary tract infection model. E. coli CN1016 reconstituted with type 1 fimbriae (E. coli CN1018) had restored virulence similar to that of the wild-type parent strain. These results show that type 1 fimbriae in the genetic background of a uropathogenic strain contribute to the pathogenesis of E. coli in the urinary tract. Images Fig. 3 Fig. 4 PMID:8790416

  4. Role of deoxyribose catabolism in colonization of the murine intestine by pathogenic Escherichia coli strains.

    PubMed

    Martinez-Jéhanne, Vanessa; du Merle, Laurence; Bernier-Fébreau, Christine; Usein, Codruta; Gassama-Sow, Amy; Wane, Abdul-Aziz; Gouali, Malika; Damian, Maria; Aïdara-Kane, Awa; Germani, Yves; Fontanet, Arnaud; Coddeville, Bernadette; Guérardel, Yann; Le Bouguénec, Chantal

    2009-04-01

    We previously suggested that the ability to metabolize deoxyribose, a phenotype encoded by the deoK operon, is associated with the pathogenic potential of Escherichia coli strains. Carbohydrate metabolism is thought to provide the nutritional support required for E. coli to colonize the intestine. We therefore investigated the role of deoxyribose catabolism in the colonization of the gut, which acts as a reservoir, by pathogenic E. coli strains. Molecular and biochemical characterization of 1,221 E. coli clones from various collections showed this biochemical trait to be common in the E. coli species (33.6%). However, multivariate analysis evidenced a higher prevalence of sugar-metabolizing E. coli clones in the stools of patients from countries in which intestinal diseases are endemic. Diarrhea processes frequently involve the destruction of intestinal epithelia, so it is plausible that such clones may be positively selected for in intestines containing abundant DNA, and consequently deoxyribose. Statistical analysis also indicated that symptomatic clinical disorders and the presence of virulence factors specific to extraintestinal pathogenic E. coli were significantly associated with an increased risk of biological samples and clones testing positive for deoxyribose. Using the streptomycin-treated-mouse model of intestinal colonization, we demonstrated the involvement of the deoK operon in gut colonization by two pathogenic isolates (one enteroaggregative and one uropathogenic strain). These results, indicating that deoxyribose availability promotes pathogenic E. coli growth during host colonization, suggest that the acquisition of this trait may be an evolutionary step enabling these pathogens to colonize and persist in the mammalian intestine. PMID:19168744

  5. Microarray long oligo probe designing for Escherichia coli: an in-silico DNA marker extraction

    PubMed Central

    Behzadi, Payam; Najafi, Ali; Behzadi, Elham

    2016-01-01

    Introduction Urinary tract infections are predominant diseases which may be caused by different pathogenic microorganisms, particularly Escherichia coli (E.coli). DNA microarray technology is an accurate, rapid, sensitive, and specific diagnostic tool which may lead to definite diagnosis and treatment of several infectious diseases. DNA microarray is a multi-process method in which probe designing plays an important. Therefore, the authors of the present study have tried to design a range of effective and proper long oligo microarray probes for detection and identification of different strains of pathogenic E.coli and in particular, uropathogenic E.coli (UPEC). Material and methods E.coli O26 H11 11368 uid41021 was selected as the standard strain for probe designing. This strain encompasses the largest nucleotide sequence and the most number of genes among other pathogenic strains of E.coli. For performing this in silico survey, NCBI database, GReview Server, PanSeq Server, Oligoanalyzer tool, and AlleleID 7.7 were used to design accurate, appropriate, effective, and flexible long oligo microarray probes. Moreover, the genome of E.coli and its closely related microorganisms were compared. Results In this study, 15 long oligo microarray probes were designed for detecting and identifying different strains of E.coli such as UPEC. These probes possessed the best physico-chemical characteristics. The functional and structural properties of the designed probes were recognized by practical tools and softwares. Conclusions The use of reliable advanced technologies and methodologies for probe designing guarentees the high quality of microarray probes and makes DNA microarray technology more flexible and an effective diagnostic technique. PMID:27123336

  6. Methane production from kitchen waste using Escherichia coli.

    PubMed

    Jayalakshmi, S; Joseph, Kurian; Sukumaran, V

    2007-04-01

    Escherichia coli (E. coli) strain isolated from biogas plant sludge was examined for its ability to enhance biogas from kitchen waste during solid phase anaerobic digestion. The laboratory experiments were conducted for total solid concentrations of 20% and 22%. Kitchen waste was characterized for physico-chemical parameters and laboratory experiments were conducted with and without E. coli strain. It was found that the reactor with E. coli produced 17% more biogas than the reactors that are operated without E. coli strain.

  7. Regulation of alcohol fermentation by Escherichia coli

    SciTech Connect

    Clark, D.P.

    1990-01-01

    The purpose of this project is to elucidate the way in which the synthesis of ethanol and related fermentation products are regulated in the facultative anaerobe Escherichia coli. We are also investigating the control of other genes required for anaerobic growth. We have isolated both structural and regulatory mutations affecting the expression of alcohol dehydrogenase, the enzyme responsible for the final step in alcohol synthesis. Some of these regulatory mutations also affect other anaerobically induced genes. The adh gene has been cloned and sequenced. The ADH protein is one of the largest highly expressed proteins in E. coli and requires approximately 2700bp of DNA for its coding sequence. We have also isolated mutations affecting the fermentative lactate dehydrogenase and have recently cloned the ldh gene. In consequence it is now possible to construct E. coli strains defective in the production of any one or more of their normal fermentation products (i.e. formate, acetate, lactate, ethanol and succinate). The factors affecting ratio of fermentation products are being investigated by in vivo NMR spectroscopy.

  8. Characterization of molybdenum cofactor from Escherichia coli.

    PubMed Central

    Amy, N K; Rajagopalan, K V

    1979-01-01

    Molybdenum cofactor activity was found in the soluble fraction of cell-free extracts of Escherichia coli grown aerobically in media supplemented with molybdate. Cofactor was detected by its ability to complement the nitrate reductase-deficient mutant of Neurospora crossa, nit-1, resulting in the vitro formation of nitrate reductase activity. Acid treatment of E. coli extracts was not required for release of cofactor activity. Cofactor was able to diffuse through a membrane of nominal 2,000-molecular-weight cutoff and was insensitive to trypsin. The cofactor was associated with a carrier molecule (approximately 40,000 daltons) during gel filtration and sucrose gradient centrifugation, but was easily removed from the carrier by dialysis. The carrier molecule protected the cofactor from inactivation by heat or oxygen. E. coli grown in molybdenum-free media, without and with tungsten, synthesized a metal-free "empty" cofactor and its tungsten analog, respectively, both of which were subsequently activated by the addition of molybdate. Empty and tungsten-containing cofactor complemented the nitrate reductase subunits in the nit-1 extract, forming inactive, but intact, 7.9S nitrate reductase. Addition of molybdate to the enzyme complemented in this manner restored nitrate reductase activity. PMID:387715

  9. Role of Escherichia coli in Biofuel Production

    PubMed Central

    Koppolu, Veerendra; Vasigala, Veneela KR

    2016-01-01

    Increased energy consumption coupled with depleting petroleum reserves and increased greenhouse gas emissions have renewed our interest in generating fuels from renewable energy sources via microbial fermentation. Central to this problem is the choice of microorganism that catalyzes the production of fuels at high volumetric productivity and yield from cheap and abundantly available renewable energy sources. Microorganisms that are metabolically engineered to redirect renewable carbon sources into desired fuel products are contemplated as best choices to obtain high volumetric productivity and yield. Considering the availability of vast knowledge in genomic and metabolic fronts, Escherichia coli is regarded as a primary choice for the production of biofuels. Here, we reviewed the microbial production of liquid biofuels that have the potential to be used either alone or in combination with the present-day fuels. We specifically highlighted the metabolic engineering and synthetic biology approaches used to improve the production of biofuels from E. coli over the past few years. We also discussed the challenges that still exist for the biofuel production from E. coli and their possible solutions. PMID:27441002

  10. Role of Escherichia coli in Biofuel Production.

    PubMed

    Koppolu, Veerendra; Vasigala, Veneela Kr

    2016-01-01

    Increased energy consumption coupled with depleting petroleum reserves and increased greenhouse gas emissions have renewed our interest in generating fuels from renewable energy sources via microbial fermentation. Central to this problem is the choice of microorganism that catalyzes the production of fuels at high volumetric productivity and yield from cheap and abundantly available renewable energy sources. Microorganisms that are metabolically engineered to redirect renewable carbon sources into desired fuel products are contemplated as best choices to obtain high volumetric productivity and yield. Considering the availability of vast knowledge in genomic and metabolic fronts, Escherichia coli is regarded as a primary choice for the production of biofuels. Here, we reviewed the microbial production of liquid biofuels that have the potential to be used either alone or in combination with the present-day fuels. We specifically highlighted the metabolic engineering and synthetic biology approaches used to improve the production of biofuels from E. coli over the past few years. We also discussed the challenges that still exist for the biofuel production from E. coli and their possible solutions. PMID:27441002

  11. Role of Escherichia coli in Biofuel Production.

    PubMed

    Koppolu, Veerendra; Vasigala, Veneela Kr

    2016-01-01

    Increased energy consumption coupled with depleting petroleum reserves and increased greenhouse gas emissions have renewed our interest in generating fuels from renewable energy sources via microbial fermentation. Central to this problem is the choice of microorganism that catalyzes the production of fuels at high volumetric productivity and yield from cheap and abundantly available renewable energy sources. Microorganisms that are metabolically engineered to redirect renewable carbon sources into desired fuel products are contemplated as best choices to obtain high volumetric productivity and yield. Considering the availability of vast knowledge in genomic and metabolic fronts, Escherichia coli is regarded as a primary choice for the production of biofuels. Here, we reviewed the microbial production of liquid biofuels that have the potential to be used either alone or in combination with the present-day fuels. We specifically highlighted the metabolic engineering and synthetic biology approaches used to improve the production of biofuels from E. coli over the past few years. We also discussed the challenges that still exist for the biofuel production from E. coli and their possible solutions.

  12. Verocytotoxin-producing Escherichia coli (VTEC).

    PubMed

    Karmali, Mohamed A; Gannon, Victor; Sargeant, Jan M

    2010-01-27

    Escherichia coli O157:H7 and other Verocytotoxin-producing E. coli (VTEC) are zoonotic pathogens associated with food and waterborne illness around the world. E. coli O157:H7 has been implicated in large outbreaks as well as in sporadic cases of haemorrhagic colitis and the sometimes fatal haemolytic uremic syndrome. VTs produced by these bacteria are thought to damage host endothelial cells in small vessels of the intestine, kidney and brain resulting in thrombotic microangiopathy. All VTs have the same subunit structure, glycolipid cell receptor and inhibit protein synthesis. During VTEC infection, it is thought one or more bacterial adhesins initiates colonization and establishes intimate attachment and is responsible for the translocation of a variety of effectors which alter the structure and function of host cells. VTEC are widespread in animals but ruminants are thought to be their natural reservoir. E. coli O157:H7 colonizes the terminal colon of cattle and can be shed in very large numbers by specific herdmates known as "supershedders". Faeces containing these organisms act as a source of contamination for a variety of foods and the environment. Many VTEC control efforts have been investigated along the "farm to fork" continuum including, vaccination of cattle with colonization factors, and the use of novel antimicrobials, such as bacteriocins, chloral hydrate, bacteriophage and substances which disrupt quorum sensing. In addition, many barriers have been developed for use in the slaughter and food processing industry such as steam pasteurization and irradiation. Despite these efforts many scientific, technical and regulatory challenges remain in the control and prevention of VTEC-associated human illness.

  13. WGS accurately predicts antimicrobial resistance in Escherichia coli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objectives: To determine the effectiveness of whole-genome sequencing (WGS) in identifying resistance genotypes of multidrug-resistant Escherichia coli (E. coli) and whether these correlate with observed phenotypes. Methods: Seventy-six E. coli strains were isolated from farm cattle and measured f...

  14. Invasin gimB found in a bovine intestinal Escherichia coli with an adherent and invasive profile

    PubMed Central

    Matter, Letícia B.; Spricigo, Denis A.; Tasca, Caiane; de Vargas, Agueda C.

    2015-01-01

    The invasin gimB (genetic island associated with human newborn meningitis) is usually found in ExPEC (Extraintestinal Pathogenic Escherichia coli) such as UPEC (uropathogenic E. coli), NMEC (neonatal meningitis E. coli) and APEC (avian pathogenic E. coli). In NMEC, gimB is associated with the invasion process of the host cells. Due to the importance of E. coli as a zoonotic agent and the scarce information about the frequency of gimB-carrying strains in different animal species, the aim of this study was to investigate the presence of gimB in isolates from bovine, swine, canine and feline clinical samples. PCR was conducted on 196 isolates and the identity of the amplicons was confirmed by sequencing. Of the samples tested, only E. coli SB278/94 from a bovine specimen was positive (1/47) for gimB, which represents 2.1% of the bovine isolates. The ability of SB278/94 to adhere to and invade eukaryotic cells was confirmed by adherence and gentamicin-protection assays using HeLa cells. This is the first study that investigates for gimB in bovine, canine and feline E. coli isolates and shows E. coli from the intestinal-bovine samples harboring gimB. PMID:26413073

  15. Both Host and Pathogen Factors Predispose to Escherichia coli Urinary-Source Bacteremia in Hospitalized Patients

    PubMed Central

    Marschall, Jonas; Zhang, Lixin; Foxman, Betsy; Warren, David K.; Henderson, Jeffrey P.

    2012-01-01

    Background. The urinary tract is the most common source for Escherichia coli bacteremia. Mortality from E. coli urinary-source bacteremia is higher than that from urinary tract infection. Predisposing factors for urinary-source E. coli bacteremia are poorly characterized. Methods. In order to identify urinary-source bacteremia risk factors, we conducted a 12-month prospective cohort study of adult inpatients with E. coli bacteriuria that were tested for bacteremia within ±1 day of the bacteriuria. Patients with bacteremia were compared with those without bacteremia. Bacterial isolates from urine were screened for 16 putative virulence genes using high-throughput dot-blot hybridization. Results. Twenty-four of 156 subjects (15%) had E. coli bacteremia. Bacteremic patients were more likely to have benign prostatic hyperplasia (56% vs 19%; P = .04), a history of urogenital surgery (63% vs 28%; P = .001), and presentation with hesitancy/retention (21% vs 4%; P = .002), fever (63% vs 38%; P = .02), and pyelonephritis (67% vs 41%; P = .02). The genes kpsMT (group II capsule) (17 [71%] vs 62 [47%]; P = .03) and prf (P-fimbriae family) (13 [54%] vs 40 [30%]; P = .02) were more frequent in the urinary strains from bacteremic patients. Symptoms of hesitancy/retention (odds ratio [OR], 7.8; 95% confidence interval [CI], 1.6–37), history of a urogenital procedure (OR, 5.4; 95% CI, 2–14.7), and presence of kpsMT (OR, 2.9; 95% CI, 1–8.2) independently predicted bacteremia. Conclusions. Bacteremia secondary to E. coli bacteriuria was frequent (15%) in those tested for it. Urinary stasis, surgical disruption of urogenital tissues, and a bacterial capsule characteristic contribute to systemic invasion by uropathogenic E. coli. PMID:22431806

  16. Efficient production of indigoidine in Escherichia coli.

    PubMed

    Xu, Fuchao; Gage, David; Zhan, Jixun

    2015-08-01

    Indigoidine is a bacterial natural product with antioxidant and antimicrobial activities. Its bright blue color resembles the industrial dye indigo, thus representing a new natural blue dye that may find uses in industry. In our previous study, an indigoidine synthetase Sc-IndC and an associated helper protein Sc-IndB were identified from Streptomyces chromofuscus ATCC 49982 and successfully expressed in Escherichia coli BAP1 to produce the blue pigment at 3.93 g/l. To further improve the production of indigoidine, in this work, the direct biosynthetic precursor L-glutamine was fed into the fermentation broth of the engineered E. coli strain harboring Sc-IndC and Sc-IndB. The highest titer of indigoidine reached 8.81 ± 0.21 g/l at 1.46 g/l L-glutamine. Given the relatively high price of L-glutamine, a metabolic engineering technique was used to directly enhance the in situ supply of this precursor. A glutamine synthetase gene (glnA) was amplified from E. coli and co-expressed with Sc-indC and Sc-indB in E. coli BAP1, leading to the production of indigoidine at 5.75 ± 0.09 g/l. Because a nitrogen source is required for amino acid biosynthesis, we then tested the effect of different nitrogen-containing salts on the supply of L-glutamine and subsequent indigoidine production. Among the four tested salts including (NH4)2SO4, NH4Cl, (NH4)2HPO4 and KNO3, (NH4)2HPO4 showed the best effect on improving the titer of indigoidine. Different concentrations of (NH4)2HPO4 were added to the fermentation broths of E. coli BAP1/Sc-IndC+Sc-IndB+GlnA, and the titer reached the highest (7.08 ± 0.11 g/l) at 2.5 mM (NH4)2HPO4. This work provides two efficient methods for the production of this promising blue pigment in E. coli.

  17. The eclipse period of Escherichia coli.

    PubMed

    von Freiesleben, U; Krekling, M A; Hansen, F G; Løbner-Olesen, A

    2000-11-15

    The minimal time between successive initiations on the same origin (the eclipse) in Escherichia coli was determined to be approximately 25-30 min. An inverse relationship was found between the length of the eclipse and the amount of Dam methyltransferase in the cell, indicating that the eclipse corresponds to the period of origin hemimethylation. The SeqA protein was absolutely required for the eclipse, and DnaA titration studies suggested that the SeqA protein prevented the binding of multiple DnaA molecules on oriC (initial complex formation). No correlation between the amount of SeqA and eclipse length was revealed, but increased SeqA levels affected chromosome partitioning and/or cell division. This was corroborated further by an aberrant nucleoid distribution in SeqA-deficient cells. We suggest that the SeqA protein's role in maintaining the eclipse is tied to a function in chromosome organization.

  18. Animal models of enteroaggregative Escherichia coli infection

    PubMed Central

    Philipson, Casandra W.; Bassaganya-Riera, Josep; Hontecillas, Raquel

    2013-01-01

    Enteroaggregative Escherichia coli (EAEC) has been acknowledged as an emerging cause of gastroenteritis worldwide for over two decades. Epidemiologists are revealing the role of EAEC in diarrheal outbreaks as a more common occurrence than ever suggested before. EAEC induced diarrhea is most commonly associated with travelers, children and immunocompromised individuals however its afflictions are not limited to any particular demographic. Many attributes have been discovered and characterized surrounding the capability of EAEC to provoke a potent pro-inflammatory immune response, however cellular and molecular mechanisms underlying initiation, progression and outcomes are largely unknown. This limited understanding can be attributed to heterogeneity in strains and the lack of adequate animal models. This review aims to summarize current knowledge about EAEC etiology, pathogenesis and clinical manifestation. Additionally, current animal models and their limitations will be discussed along with the value of applying systems-wide approaches such as computational modeling to study host-EAEC interactions. PMID:23680797

  19. Novel antigens for enterotoxigenic Escherichia coli vaccines.

    PubMed

    Fleckenstein, James; Sheikh, Alaullah; Qadri, Firdausi

    2014-05-01

    Enterotoxigenic Escherichia coli (ETEC) are the most common bacterial pathogens causing diarrhea in developing countries where they lead to hundreds of thousands of deaths, mostly in children. These organisms are a leading cause of diarrheal illness in travelers to endemic countries. ETEC pathogenesis, and consequently vaccine approaches, have largely focused on plasmid-encoded enterotoxins or fimbrial colonization factors. To date these approaches have not yielded a broadly protective vaccine. However, recent studies suggest that ETEC pathogenesis is more complex than previously appreciated and involves additional plasmid and chromosomally encoded virulence molecules that can be targeted in vaccines. Here, we review recent novel antigen discovery efforts, potential contribution of these proteins to the molecular pathogenesis of ETEC and protective immunity, and the potential implications for development of next generation vaccines for important pathogens. These proteins may help to improve the effectiveness of future vaccines by making them simpler and possibly broadly protective because of their conserved nature. PMID:24702311

  20. Mechanism of Escherichia coli Resistance to Pyrrhocoricin

    PubMed Central

    Narayanan, Shalini; Modak, Joyanta K.; Ryan, Catherine S.; Garcia-Bustos, Jose; Davies, John K.

    2014-01-01

    Due to their lack of toxicity to mammalian cells and good serum stability, proline-rich antimicrobial peptides (PR-AMPs) have been proposed as promising candidates for the treatment of infections caused by antimicrobial-resistant bacterial pathogens. It has been hypothesized that these peptides act on multiple targets within bacterial cells, and therefore the likelihood of the emergence of resistance was considered to be low. Here, we show that spontaneous Escherichia coli mutants resistant to pyrrhocoricin arise at a frequency of approximately 6 × 10−7. Multiple independently derived mutants all contained a deletion in a nonessential gene that encodes the putative peptide uptake permease SbmA. Sensitivity could be restored to the mutants by complementation with an intact copy of the sbmA gene. These findings question the viability of the development of insect PR-AMPs as antimicrobials. PMID:24590485

  1. Direct Upstream Motility in Escherichia coli

    PubMed Central

    Kaya, Tolga; Koser, Hur

    2012-01-01

    We provide an experimental demonstration of positive rheotaxis (rapid and continuous upstream motility) in wild-type Escherichia coli freely swimming over a surface. This hydrodynamic phenomenon is dominant below a critical shear rate and robust against Brownian motion and cell tumbling. We deduce that individual bacteria entering a flow system can rapidly migrate upstream (>20 μm/s) much faster than a gradually advancing biofilm. Given a bacterial population with a distribution of sizes and swim speeds, local shear rate near the surface determines the dominant hydrodynamic mode for motility, i.e., circular or random trajectories for low shear rates, positive rheotaxis for moderate flow, and sideways swimming at higher shear rates. Faster swimmers can move upstream more rapidly and at higher shear rates, as expected. Interestingly, we also find on average that both swim speed and upstream motility are independent of cell aspect ratio. PMID:22500751

  2. REPRESSION OF TRYPTOPHANASE SYNTHESIS IN ESCHERICHIA COLI.

    PubMed

    BEGGS, W H; LICHSTEIN, H C

    1965-04-01

    Beggs, William H. (University of Cincinnati, Cincinnati, Ohio), and Herman C. Lichstein. Repression of tryptophanase synthesis in Escherichia coli. J. Bacteriol. 89:996-1004. 1965.-The nature of the glucose effect on tryptophanase in Escherichia coli (Crookes) was investigated to test the catabolite-repression hypothesis. Under static conditions of growth in the presence of 0.005 m glucose, tryptophanase was repressed and remained so upon continued static incubation subsequent to glucose exhaustion. Aeration following glucose exhaustion under static cultural conditions resulted in rapid enzyme synthesis. In the absence of glucose, certain amino acids repressed tryptophanase synthesis early in the growth cycle under aerated conditions. An inverse relationship was observed between the concentration of acid-hydrolyzed casein and the level of tryptophanase. At 3 hr, enzyme activity in cells grown in media containing 0.05% acid-hydrolyzed casein was at least five times that of cells grown in the presence of 1% casein. Addition of 0.005 m d- or l-serine to a 0.05% acid-hydrolyzed casein medium rendered the medium capable of strongly repressing tryptophanase. Glucose-expended medium was prepared by allowing cells to grow and exhaust glucose in static culture. When this expended medium was recovered and inoculated with fresh cells not previously exposed to glucose, tryptophanase synthesis was repressed for a short period in shake culture, but in static culture enzyme synthesis was only slightly affected. When the expended medium was prepared from shake cultures, fresh cells were not repressed strongly when subsequent incubation was carried out aerobically. The tryptophan pool in glucose-repressed cells grown in shake culture was appreciably less than in cells grown in the absence of glucose or in cells undergoing synthesis of tryptophanase after exhaustion of the sugar.

  3. Molecular analysis of type 3 fimbrial genes from Escherichia coli, Klebsiella and Citrobacter species

    PubMed Central

    2010-01-01

    Background Catheter-associated urinary tract infection (CAUTI) is the most common nosocomial infection in the United States and is caused by a range of uropathogens. Biofilm formation by uropathogens that cause CAUTI is often mediated by cell surface structures such as fimbriae. In this study, we characterised the genes encoding type 3 fimbriae from CAUTI strains of Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Citrobacter koseri and Citrobacter freundii. Results Phylogenetic analysis of the type 3 fimbrial genes (mrkABCD) from 39 strains revealed they clustered into five distinct clades (A-E) ranging from one to twenty-three members. The majority of sequences grouped in clade A, which was represented by the mrk gene cluster from the genome sequenced K. pneumoniae MGH78578. The E. coli and K. pneumoniae mrkABCD gene sequences clustered together in two distinct clades, supporting previous evidence for the occurrence of inter-genera lateral gene transfer. All of the strains examined caused type 3 fimbriae mediated agglutination of tannic acid treated human erythrocytes despite sequence variation in the mrkD-encoding adhesin gene. Type 3 fimbriae deletion mutants were constructed in 13 representative strains and were used to demonstrate a direct role for type 3 fimbriae in biofilm formation. Conclusions The expression of functional type 3 fimbriae is common to many Gram-negative pathogens that cause CAUTI and is strongly associated with biofilm growth. Our data provides additional evidence for the spread of type 3 fimbrial genes by lateral gene transfer. Further work is now required to substantiate the clade structure reported here by examining more strains as well as other bacterial genera that make type 3 fimbriae and cause CAUTI. PMID:20576143

  4. Development of a Vaccine against Escherichia coli Urinary Tract Infections

    PubMed Central

    Mobley, Harry L. T.; Alteri, Christopher J.

    2015-01-01

    Urinary tract infection (UTI) is the second most common infection in humans after those involving the respiratory tract. This results not only in huge annual economic costs, but in decreased workforce productivity and high patient morbidity. Most infections are caused by uropathogenic Escherichia coli (UPEC). Antibiotic treatment is generally effective for eradication of the infecting strain; however, documentation of increasing antibiotic resistance, allergic reaction to certain pharmaceuticals, alteration of normal gut flora, and failure to prevent recurrent infections represent significant barriers to treatment. As a result, approaches to prevent UTI such as vaccination represent a gap that must be addressed. Our laboratory has made progress toward development of a preventive vaccine against UPEC. The long-term research goal is to prevent UTIs in women with recurrent UTIs. Our objective has been to identify the optimal combination of protective antigens for inclusion in an effective UTI vaccine, optimal adjuvant, optimal dose, and optimal route of delivery. We hypothesized that a multi-subunit vaccine elicits antibody that protects against experimental challenge with UPEC strains. We have systematically identified four antigens that can individually protect experimentally infected mice from colonization of the bladder and/or kidneys by UPEC when administered intranasally with cholera toxin (CT) as an adjuvant. To advance the vaccine for utility in humans, we will group the individual antigens, all associated with iron acquisition (IreA, Hma, IutA, FyuA), into an effective combination to establish a multi-subunit vaccine. We demonstrated for all four vaccine antigens that antigen-specific serum IgG represents a strong correlate of protection in vaccinated mice. High antibody titers correlate with low colony forming units (CFUs) of UPEC following transurethral challenge of vaccinated mice. However, the contribution of cell-mediated immunity cannot be ruled out and

  5. Development of a Vaccine against Escherichia coli Urinary Tract Infections.

    PubMed

    Mobley, Harry L T; Alteri, Christopher J

    2015-12-31

    Urinary tract infection (UTI) is the second most common infection in humans after those involving the respiratory tract. This results not only in huge annual economic costs, but in decreased workforce productivity and high patient morbidity. Most infections are caused by uropathogenic Escherichia coli (UPEC). Antibiotic treatment is generally effective for eradication of the infecting strain; however, documentation of increasing antibiotic resistance, allergic reaction to certain pharmaceuticals, alteration of normal gut flora, and failure to prevent recurrent infections represent significant barriers to treatment. As a result, approaches to prevent UTI such as vaccination represent a gap that must be addressed. Our laboratory has made progress toward development of a preventive vaccine against UPEC. The long-term research goal is to prevent UTIs in women with recurrent UTIs. Our objective has been to identify the optimal combination of protective antigens for inclusion in an effective UTI vaccine, optimal adjuvant, optimal dose, and optimal route of delivery. We hypothesized that a multi-subunit vaccine elicits antibody that protects against experimental challenge with UPEC strains. We have systematically identified four antigens that can individually protect experimentally infected mice from colonization of the bladder and/or kidneys by UPEC when administered intranasally with cholera toxin (CT) as an adjuvant. To advance the vaccine for utility in humans, we will group the individual antigens, all associated with iron acquisition (IreA, Hma, IutA, FyuA), into an effective combination to establish a multi-subunit vaccine. We demonstrated for all four vaccine antigens that antigen-specific serum IgG represents a strong correlate of protection in vaccinated mice. High antibody titers correlate with low colony forming units (CFUs) of UPEC following transurethral challenge of vaccinated mice. However, the contribution of cell-mediated immunity cannot be ruled out and

  6. Development of a Vaccine against Escherichia coli Urinary Tract Infections.

    PubMed

    Mobley, Harry L T; Alteri, Christopher J

    2015-01-01

    Urinary tract infection (UTI) is the second most common infection in humans after those involving the respiratory tract. This results not only in huge annual economic costs, but in decreased workforce productivity and high patient morbidity. Most infections are caused by uropathogenic Escherichia coli (UPEC). Antibiotic treatment is generally effective for eradication of the infecting strain; however, documentation of increasing antibiotic resistance, allergic reaction to certain pharmaceuticals, alteration of normal gut flora, and failure to prevent recurrent infections represent significant barriers to treatment. As a result, approaches to prevent UTI such as vaccination represent a gap that must be addressed. Our laboratory has made progress toward development of a preventive vaccine against UPEC. The long-term research goal is to prevent UTIs in women with recurrent UTIs. Our objective has been to identify the optimal combination of protective antigens for inclusion in an effective UTI vaccine, optimal adjuvant, optimal dose, and optimal route of delivery. We hypothesized that a multi-subunit vaccine elicits antibody that protects against experimental challenge with UPEC strains. We have systematically identified four antigens that can individually protect experimentally infected mice from colonization of the bladder and/or kidneys by UPEC when administered intranasally with cholera toxin (CT) as an adjuvant. To advance the vaccine for utility in humans, we will group the individual antigens, all associated with iron acquisition (IreA, Hma, IutA, FyuA), into an effective combination to establish a multi-subunit vaccine. We demonstrated for all four vaccine antigens that antigen-specific serum IgG represents a strong correlate of protection in vaccinated mice. High antibody titers correlate with low colony forming units (CFUs) of UPEC following transurethral challenge of vaccinated mice. However, the contribution of cell-mediated immunity cannot be ruled out and

  7. Lineage-Specific Methyltransferases Define the Methylome of the Globally Disseminated Escherichia coli ST131 Clone

    PubMed Central

    Forde, Brian M.; Phan, Minh-Duy; Gawthorne, Jayde A.; Ashcroft, Melinda M.; Stanton-Cook, Mitchell; Sarkar, Sohinee; Peters, Kate M.; Chan, Kok-Gan; Chong, Teik Min; Yin, Wai-Fong; Upton, Mathew

    2015-01-01

    ABSTRACT Escherichia coli sequence type 131 (ST131) is a clone of uropathogenic E. coli that has emerged rapidly and disseminated globally in both clinical and community settings. Members of the ST131 lineage from across the globe have been comprehensively characterized in terms of antibiotic resistance, virulence potential, and pathogenicity, but to date nothing is known about the methylome of these important human pathogens. Here we used single-molecule real-time (SMRT) PacBio sequencing to determine the methylome of E. coli EC958, the most-well-characterized completely sequenced ST131 strain. Our analysis of 52,081 methylated adenines in the genome of EC958 discovered three m6A methylation motifs that have not been described previously. Subsequent SMRT sequencing of isogenic knockout mutants identified the two type I methyltransferases (MTases) and one type IIG MTase responsible for m6A methylation of novel recognition sites. Although both type I sites were rare, the type IIG sites accounted for more than 12% of all methylated adenines in EC958. Analysis of the distribution of MTase genes across 95 ST131 genomes revealed their prevalence is highly conserved within the ST131 lineage, with most variation due to the presence or absence of mobile genetic elements on which individual MTase genes are located. PMID:26578678

  8. Chemoreceptors of Escherichia coli CFT073 play redundant roles in chemotaxis toward urine.

    PubMed

    Raterman, Erica L; Welch, Rodney A

    2013-01-01

    Community-acquired urinary tract infections (UTIs) are commonly caused by uropathogenic Escherichia coli (UPEC). We hypothesize that chemotaxis toward ligands present in urine could direct UPEC into and up the urinary tract. Wild-type E. coli CFT073 and chemoreceptor mutants with tsr, tar, or aer deletions were tested for chemotaxis toward human urine in the capillary tube assay. Wild-type CFT073 was attracted toward urine, and Tsr and Tar were the chemoreceptors mainly responsible for mediating this response. The individual components of urine including L-amino acids, D-amino acids and various organic compounds were also tested in the capillary assay with wild-type CFT073. Our results indicate that CFT073 is attracted toward some L- amino acids and possibly toward some D-amino acids but not other common compounds found in urine such as urea, creatinine and glucuronic acid. In the murine model of UTI, the loss of any two chemoreceptors did not affect the ability of the bacteria to compete with the wild-type strain. Our data suggest that the presence of any strong attractant and its associated chemoreceptor might be sufficient for colonization of the urinary tract and that amino acids are the main chemoattractants for E. coli strain CFT073 in this niche.

  9. The serine protease Pic as a virulence factor of atypical enteropathogenic Escherichia coli.

    PubMed

    Abreu, Afonso G; Abe, Cecilia M; Nunes, Kamila O; Moraes, Claudia T P; Chavez-Dueñas, Lucia; Navarro-Garcia, Fernando; Barbosa, Angela S; Piazza, Roxane M F; Elias, Waldir P

    2016-01-01

    Autotransporter proteins (AT) are associated with bacterial virulence attributes. Originally identified in enteroaggregative Escherichia coli (EAEC), Shigella flexneri 2a and uropathogenic E. coli, the serine protease Pic is one of these AT. We have previously detected one atypical enteropathogenic E. coli strain (BA589) carrying the pic gene. In the present study, we characterized the biological activities of Pic produced by BA589 both in vitro and in vivo. Contrarily to other Pic-producers bacteria, pic in BA589 is located on a high molecular weight plasmid. PicBA589 was able to agglutinate rabbit erythrocytes, cleave mucin and degrade complement system molecules. BA589 was able to colonize mice intestines, and an intense mucus production was observed. The BA589Δpic mutant lost the capacity to colonize as well as the above-mentioned in vitro activities. Thus, Pic represents an additional virulence factor in aEPEC strain BA589, associated with adherence, colonization and evasion from the innate immune system.

  10. Antibacterial activity of isolated phenolic compounds from cranberry (Vaccinium macrocarpon) against Escherichia coli.

    PubMed

    Rodríguez-Pérez, Celia; Quirantes-Piné, Rosa; Uberos, José; Jiménez-Sánchez, Cecilia; Peña, Alejandro; Segura-Carretero, Antonio

    2016-03-01

    Phenolic compounds from a cranberry extract were isolated in order to assess their contribution to the antibacterial activity against uropathogenic strains of Escherichia coli (UPEC). With this purpose, a total of 25 fractions from a cranberry extract were isolated using semipreparative high performance liquid chromatography (HPLC) and characterized based on the results obtained by reversed-phase HPLC coupled to mass spectrometry detection. Then, the effects on UPEC surface hydrophobicity and biofilm formation of the cranberry extract as well as the purest fractions (a total of 13) were tested. As expected, the whole extract presented a powerful antibacterial activity against UPEC while the selected fractions presented a different behavior. Myricetin and quercitrin significantly decreased (p < 0.05) E. coli biofilm formation compared with the control, while dihydroferulic acid glucuronide, procyanidin A dimer, quercetin glucoside, myricetin and prodelphinidin B led to a significant decrease of the surface hydrophobicity compared with the control. The results suggest that apart from proanthocyanidins, other compounds, mainly flavonoids, can act against E. coli biofilm formation and also modify UPEC surface hydrophobicity in vitro, one of the first steps of adhesion. PMID:26902395

  11. Antibacterial activity of isolated phenolic compounds from cranberry (Vaccinium macrocarpon) against Escherichia coli.

    PubMed

    Rodríguez-Pérez, Celia; Quirantes-Piné, Rosa; Uberos, José; Jiménez-Sánchez, Cecilia; Peña, Alejandro; Segura-Carretero, Antonio

    2016-03-01

    Phenolic compounds from a cranberry extract were isolated in order to assess their contribution to the antibacterial activity against uropathogenic strains of Escherichia coli (UPEC). With this purpose, a total of 25 fractions from a cranberry extract were isolated using semipreparative high performance liquid chromatography (HPLC) and characterized based on the results obtained by reversed-phase HPLC coupled to mass spectrometry detection. Then, the effects on UPEC surface hydrophobicity and biofilm formation of the cranberry extract as well as the purest fractions (a total of 13) were tested. As expected, the whole extract presented a powerful antibacterial activity against UPEC while the selected fractions presented a different behavior. Myricetin and quercitrin significantly decreased (p < 0.05) E. coli biofilm formation compared with the control, while dihydroferulic acid glucuronide, procyanidin A dimer, quercetin glucoside, myricetin and prodelphinidin B led to a significant decrease of the surface hydrophobicity compared with the control. The results suggest that apart from proanthocyanidins, other compounds, mainly flavonoids, can act against E. coli biofilm formation and also modify UPEC surface hydrophobicity in vitro, one of the first steps of adhesion.

  12. The crystal structure Escherichia coli Spy.

    PubMed

    Kwon, Eunju; Kim, Dong Young; Gross, Carol A; Gross, John D; Kim, Kyeong Kyu

    2010-11-01

    Escherichia coli spheroplast protein y (EcSpy) is a small periplasmic protein that is homologous with CpxP, an inhibitor of the extracytoplasmic stress response. Stress conditions such as spheroplast formation induce the expression of Spy via the Cpx or the Bae two-component systems in E. coli, though the function of Spy is unknown. Here, we report the crystal structure of EcSpy, which reveals a long kinked hairpin-like structure of four α-helices that form an antiparallel dimer. The dimer contains a curved oval shape with a highly positively charged concave surface that may function as a ligand binding site. Sequence analysis reveals that Spy is highly conserved over the Enterobacteriaceae family. Notably, three conserved regions that contain identical residues and two LTxxQ motifs are placed at the horizontal end of the dimer structure, stabilizing the overall fold. CpxP also contains the conserved sequence motifs and has a predicted secondary structure similar to Spy, suggesting that Spy and CpxP likely share the same fold.

  13. gltBDF operon of Escherichia coli.

    PubMed Central

    Castaño, I; Bastarrachea, F; Covarrubias, A A

    1988-01-01

    A 2.0-kilobase DNA fragment carrying antibiotic resistance markers was inserted into the gltB gene of Escherichia coli previously cloned in a multicopy plasmid. Replacement of the chromosomal gltB+ gene by the gltB225::omega mutation led to cells unable to synthesize glutamate synthase, utilize growth rate-limiting nitrogen sources, or derepress their glutamine synthetase. The existence of a gltBDF operon encoding the large (gltB) and small (gltD) subunits of glutamate synthase and a regulatory peptide (gltF) at 69 min of the E. coli linkage map was deduced from complementation analysis. A plasmid carrying the entire gltB+D+F+ operon complemented cells for all three of the mutant phenotypes associated with the polar gltB225::omega mutation in the chromosome. By contrast, plasmids carrying gltB+ only complemented cells for glutamate synthase activity. A major tricistronic mRNA molecule was detected from Northern (RNA blot) DNA-RNA hybridization experiments with DNA probes containing single genes of the operon. A 30,200-dalton polypeptide was identified as the gltF product, the lack of which was responsible for the inability of cells to use nitrogen-limiting sources associated with gltB225::omega. Images PMID:2448295

  14. Independence of replisomes in Escherichia coli chromosomalreplication

    SciTech Connect

    Breier, Adam M.; Weier, Heinz-Ulrich G.; Cozzarelli, Nicholas R.

    2005-03-13

    In Escherichia coli DNA replication is carried out by the coordinated action of the proteins within a replisome. After replication initiation, the two bidirectionally oriented replisomes from a single origin are colocalized into higher-order structures termed replication factories. The factory model postulated that the two replisomes are also functionally coupled. We tested this hypothesis by using DNA combing and whole-genome microarrays. Nascent DNA surrounding oriC in single, combed chromosomes showed instead that one replisome, usually the leftward one, was significantly ahead of the other 70% of the time. We next used microarrays to follow replication throughout the genome by measuring DNA copy number. We found in multiple E. coli strains that the replisomes are independent, with the leftward replisome ahead of the rightward one. The size of the bias was strain-specific, varying from 50 to 130 kb in the array results. When we artificially blocked one replisome, the other continued unabated, again demonstrating independence. We suggest an improved version of the factory model that retains the advantages of threading DNA through colocalized replisomes at about equal rates, but allows the cell flexibility to overcome obstacles encountered during elongation.

  15. The extracellular RNA complement of Escherichia coli

    PubMed Central

    Ghosal, Anubrata; Upadhyaya, Bimal Babu; Fritz, Joëlle V; Heintz-Buschart, Anna; Desai, Mahesh S; Yusuf, Dilmurat; Huang, David; Baumuratov, Aidos; Wang, Kai; Galas, David; Wilmes, Paul

    2015-01-01

    The secretion of biomolecules into the extracellular milieu is a common and well-conserved phenomenon in biology. In bacteria, secreted biomolecules are not only involved in intra-species communication but they also play roles in inter-kingdom exchanges and pathogenicity. To date, released products, such as small molecules, DNA, peptides, and proteins, have been well studied in bacteria. However, the bacterial extracellular RNA complement has so far not been comprehensively characterized. Here, we have analyzed, using a combination of physical characterization and high-throughput sequencing, the extracellular RNA complement of both outer membrane vesicle (OMV)-associated and OMV-free RNA of the enteric Gram-negative model bacterium Escherichia coli K-12 substrain MG1655 and have compared it to its intracellular RNA complement. Our results demonstrate that a large part of the extracellular RNA complement is in the size range between 15 and 40 nucleotides and is derived from specific intracellular RNAs. Furthermore, RNA is associated with OMVs and the relative abundances of RNA biotypes in the intracellular, OMV and OMV-free fractions are distinct. Apart from rRNA fragments, a significant portion of the extracellular RNA complement is composed of specific cleavage products of functionally important structural noncoding RNAs, including tRNAs, 4.5S RNA, 6S RNA, and tmRNA. In addition, the extracellular RNA pool includes RNA biotypes from cryptic prophages, intergenic, and coding regions, of which some are so far uncharacterised, for example, transcripts mapping to the fimA-fimL and ves-spy intergenic regions. Our study provides the first detailed characterization of the extracellular RNA complement of the enteric model bacterium E. coli. Analogous to findings in eukaryotes, our results suggest the selective export of specific RNA biotypes by E. coli, which in turn indicates a potential role for extracellular bacterial RNAs in intercellular communication. PMID:25611733

  16. Rapid and sensitive detection of fluoroquinolone-resistant Escherichia coli from urine samples using a genotyping DNA microarray.

    PubMed

    Yu, Xiaolei; Susa, Milorad; Weile, Jan; Knabbe, Cornelius; Schmid, Rolf D; Bachmann, Till T

    2007-10-01

    Urinary tract infections (UTI) are among the most common bacterial infections in humans, with Escherichia coli being the major cause of infection. Fluoroquinolone resistance of uropathogenic E. coli has increased significantly over the last decade. In this study a microarray-based assay was developed and applied, which provides a rapid, sensitive and specific detection of fluoroquinolone-resistant E. coli in urine. The capture probes were designed against previously identified and described hotspots for quinolone resistance (codons 83 and 87 of gyrA). The key goals of this development were to reduce assay time while increasing the sensitivity and specificity as compared with a pilot version of a gyrA genotyping DNA microarray. The performance of the assay was demonstrated with pure cultures of 30 E. coli isolates as well as with urine samples spiked with 6 E. coli isolates. The microarray results were confirmed by standard DNA sequencing and were in full agreement with the phenotypic antimicrobial susceptibility testing using standard methods. The DNA microarray test displayed an assay time of 3.5h, a sensitivity of 100CFU/ml, and the ability to detect fluoroquinolone-resistant E. coli in the presence of a 10-fold excess of fluoroquinolone-susceptible E. coli cells. As a consequence, we believe that this microarray-based determination of antibiotics resistance has a true potential for the application in clinical routine laboratories in the future.

  17. Enteroaggregative Escherichia coli O78:H10, the Cause of an Outbreak of Urinary Tract Infection

    PubMed Central

    Scheutz, Flemming; Andersen, Rebecca L.; Menard, Megan; Boisen, Nadia; Johnston, Brian; Hansen, Dennis S.; Krogfelt, Karen A.; Nataro, James P.; Johnson, James R.

    2012-01-01

    In 1991, multiresistant Escherichia coli O78:H10 strains caused an outbreak of urinary tract infections in Copenhagen, Denmark. The phylogenetic origin, clonal background, and virulence characteristics of the outbreak isolates, and their relationship to nonoutbreak O78:H10 strains according to these traits and resistance profiles, are unknown. Accordingly, we extensively characterized 51 archived E. coli O78:H10 isolates (48 human isolates from seven countries, including 19 Copenhagen outbreak isolates, and 1 each of calf, avian, and unknown-source isolates), collected from 1956 through 2000. E. coli O78:H10 was clonally heterogeneous, comprising one dominant clonal group (61% of isolates, including all 19 outbreak isolates) from ST10 (phylogenetic group A) plus several minor clonal groups (phylogenetic groups A and D). All ST10 isolates, versus 25% of non-ST10 isolates, were identified by molecular methods as enteroaggregative E. coli (EAEC) (P < 0.001). Genes present in >90% of outbreak isolates included fimH (type 1 fimbriae; ubiquitous in E. coli); fyuA, traT, and iutA (associated with extraintestinal pathogenic E. coli [ExPEC]); and sat, pic, aatA, aggR, aggA, ORF61, aaiC, aap, and ORF3 (associated with EAEC). An outbreak isolate was lethal in a murine subcutaneous sepsis model and exhibited characteristic EAEC “stacked brick” adherence to cultured epithelial cells. Thus, the 1991 Copenhagen outbreak was caused by a tight, non-animal-associated subset within a broadly disseminated O78:H10 clonal group (ST10; phylogenetic group A), members of which exhibit both ExPEC and EAEC characteristics, whereas O78:H10 isolates overall are phylogenetically diverse. Whether ST10 O78:H10 EAEC strains are both uropathogenic and diarrheagenic warrants further investigation. PMID:22972830

  18. Escherichia coli survival in waters: temperature dependence.

    PubMed

    Blaustein, R A; Pachepsky, Y; Hill, R L; Shelton, D R; Whelan, G

    2013-02-01

    Knowing the survival rates of water-borne Escherichia coli is important in evaluating microbial contamination and making appropriate management decisions. E. coli survival rates are dependent on temperature, a dependency that is routinely expressed using an analogue of the Q₁₀ model. This suggestion was made 34 years ago based on 20 survival curves taken from published literature, but has not been revisited since then. The objective of this study was to re-evaluate the accuracy of the Q₁₀ equation, utilizing data accumulated since 1978. We assembled a database of 450 E. coli survival datasets from 70 peer-reviewed papers. We then focused on the 170 curves taken from experiments that were performed in the laboratory under dark conditions to exclude the effects of sunlight and other field factors that could cause additional variability in results. All datasets were tabulated dependencies "log concentration vs. time." There were three major patterns of inactivation: about half of the datasets had a section of fast log-linear inactivation followed by a section of slow log-linear inactivation; about a quarter of the datasets had a lag period followed by log-linear inactivation; and the remaining quarter were approximately linear throughout. First-order inactivation rate constants were calculated from the linear sections of all survival curves and the data grouped by water sources, including waters of agricultural origin, pristine water sources, groundwater and wells, lakes and reservoirs, rivers and streams, estuaries and seawater, and wastewater. Dependency of E. coli inactivation rates on temperature varied among the water sources. There was a significant difference in inactivation rate values at the reference temperature between rivers and agricultural waters, wastewaters and agricultural waters, rivers and lakes, and wastewater and lakes. At specific sites, the Q₁₀ equation was more accurate in rivers and coastal waters than in lakes making the value of

  19. TRIMETHOPRIM-SULFAMETHOXAZOLE RESISTANCE IN SEWAGE ISOLATES OF ESCHERICHIA COLI

    EPA Science Inventory

    Sewage samples from seven locations in the United States were analyzed for Escherichia coli isolates which were resistant to trimethoprim-sulfamethoxazole (SXT). The prevalence rate of SXT resistant organisms varied between the different geographical locales. The majority of th...

  20. The Escherichia coli Peripheral Inner Membrane Proteome*

    PubMed Central

    Papanastasiou, Malvina; Orfanoudaki, Georgia; Koukaki, Marina; Kountourakis, Nikos; Sardis, Marios Frantzeskos; Aivaliotis, Michalis; Karamanou, Spyridoula; Economou, Anastassios

    2013-01-01

    Biological membranes are essential for cell viability. Their functional characteristics strongly depend on their protein content, which consists of transmembrane (integral) and peripherally associated membrane proteins. Both integral and peripheral inner membrane proteins mediate a plethora of biological processes. Whereas transmembrane proteins have characteristic hydrophobic stretches and can be predicted using bioinformatics approaches, peripheral inner membrane proteins are hydrophilic, exist in equilibria with soluble pools, and carry no discernible membrane targeting signals. We experimentally determined the cytoplasmic peripheral inner membrane proteome of the model organism Escherichia coli using a multidisciplinary approach. Initially, we extensively re-annotated the theoretical proteome regarding subcellular localization using literature searches, manual curation, and multi-combinatorial bioinformatics searches of the available databases. Next we used sequential biochemical fractionations coupled to direct identification of individual proteins and protein complexes using high resolution mass spectrometry. We determined that the proposed cytoplasmic peripheral inner membrane proteome occupies a previously unsuspected ∼19% of the basic E. coli BL21(DE3) proteome, and the detected peripheral inner membrane proteome occupies ∼25% of the estimated expressed proteome of this cell grown in LB medium to mid-log phase. This value might increase when fleeting interactions, not studied here, are taken into account. Several proteins previously regarded as exclusively cytoplasmic bind membranes avidly. Many of these proteins are organized in functional or/and structural oligomeric complexes that bind to the membrane with multiple interactions. Identified proteins cover the full spectrum of biological activities, and more than half of them are essential. Our data suggest that the cytoplasmic proteome displays remarkably dynamic and extensive communication with

  1. Structural Sampling of Glycan Interaction Profiles Reveals Mucosal Receptors for Fimbrial Adhesins of Enterotoxigenic Escherichia coli

    PubMed Central

    Lonardi, Emanuela; Moonens, Kristof; Buts, Lieven; de Boer, Arjen R.; Olsson, Johan D. M.; Weiss, Manfred S.; Fabre, Emeline; Guérardel, Yann; Deelder, André M.; Oscarson, Stefan; Wuhrer, Manfred; Bouckaert, Julie

    2013-01-01

    Fimbriae are long, proteinaceous adhesion organelles expressed on the bacterial envelope, evolutionarily adapted by Escherichia coli strains for the colonization of epithelial linings. Using glycan arrays of the Consortium for Functional Glycomics (CFG), the lectin domains were screened of the fimbrial adhesins F17G and FedF from enterotoxigenic E. coli (ETEC) and of the FimH adhesin from uropathogenic E. coli. This has led to the discovery of a more specific receptor for F17G, GlcNAcβ1,3Gal. No significant differences emerged from the glycan binding profiles of the F17G lectin domains from five different E. coli strains. However, strain-dependent amino acid variations, predominantly towards the positively charged arginine, were indicated by sulfate binding in FedF and F17G crystal structures. For FedF, no significant binders could be observed on the CFG glycan array. Hence, a shotgun array was generated from microvilli scrapings of the distal jejunum of a 3-week old piglet about to be weaned. On this array, the blood group A type 1 hexasaccharide emerged as a receptor for the FedF lectin domain and remarkably also for F18-fimbriated E. coli. F17G was found to selectively recognize glycan species with a terminal GlcNAc, typifying intestinal mucins. In conclusion, F17G and FedF recognize long glycan sequences that could only be identified using the shotgun approach. Interestingly, ETEC strains display a large capacity to adapt their fimbrial adhesins to ecological niches via charge-driven interactions, congruent with binding to thick mucosal surfaces displaying an acidic gradient along the intestinal tract. PMID:24833052

  2. Structural Sampling of Glycan Interaction Profiles Reveals Mucosal Receptors for Fimbrial Adhesins of Enterotoxigenic Escherichia coli.

    PubMed

    Lonardi, Emanuela; Moonens, Kristof; Buts, Lieven; de Boer, Arjen R; Olsson, Johan D M; Weiss, Manfred S; Fabre, Emeline; Guérardel, Yann; Deelder, André M; Oscarson, Stefan; Wuhrer, Manfred; Bouckaert, Julie

    2013-01-01

    Fimbriae are long, proteinaceous adhesion organelles expressed on the bacterial envelope, evolutionarily adapted by Escherichia coli strains for the colonization of epithelial linings. Using glycan arrays of the Consortium for Functional Glycomics (CFG), the lectin domains were screened of the fimbrial adhesins F17G and FedF from enterotoxigenic E. coli (ETEC) and of the FimH adhesin from uropathogenic E. coli. This has led to the discovery of a more specific receptor for F17G, GlcNAcb1,3Gal. No significant differences emerged from the glycan binding profiles of the F17G lectin domains from five different E. coli strains. However, strain-dependent amino acid variations, predominantly towards the positively charged arginine, were indicated by sulfate binding in FedF and F17G crystal structures. For FedF, no significant binders could be observed on the CFG glycan array. Hence, a shotgun array was generated from microvilli scrapings of the distal jejunum of a 3-week old piglet about to be weaned. On this array, the blood group A type 1 hexasaccharide emerged as a receptor for the FedF lectin domain and remarkably also for F18-fimbriated E. coli. F17G was found to selectively recognize glycan species with a terminal GlcNAc, typifying intestinal mucins. In conclusion, F17G and FedF recognize long glycan sequences that could only be identified using the shotgun approach. Interestingly, ETEC strains display a large capacity to adapt their fimbrial adhesins to ecological niches via charge-driven interactions, congruent with binding to thick mucosal surfaces displaying an acidic gradient along the intestinal tract. PMID:24833052

  3. A DNA structural atlas for Escherichia coli.

    PubMed

    Pedersen, A G; Jensen, L J; Brunak, S; Staerfeldt, H H; Ussery, D W

    2000-06-16

    We have performed a computational analysis of DNA structural features in 18 fully sequenced prokaryotic genomes using models for DNA curvature, DNA flexibility, and DNA stability. The structural values that are computed for the Escherichia coli chromosome are significantly different from (and generally more extreme than) that expected from the nucleotide composition. To aid this analysis, we have constructed tools that plot structural measures for all positions in a long DNA sequence (e.g. an entire chromosome) in the form of color-coded wheels (http://www.cbs.dtu. dk/services/GenomeAtlas/). We find that these "structural atlases" are useful for the discovery of interesting features that may then be investigated in more depth using statistical methods. From investigation of the E. coli structural atlas, we discovered a genome-wide trend, where an extended region encompassing the terminus displays a high of level curvature, a low level of flexibility, and a low degree of helix stability. The same situation is found in the distantly related Gram-positive bacterium Bacillus subtilis, suggesting that the phenomenon is biologically relevant. Based on a search for long DNA segments where all the independent structural measures agree, we have found a set of 20 regions with identical and very extreme structural properties. Due to their strong inherent curvature, we suggest that these may function as topological domain boundaries by efficiently organizing plectonemically supercoiled DNA. Interestingly, we find that in practically all the investigated eubacterial and archaeal genomes, there is a trend for promoter DNA being more curved, less flexible, and less stable than DNA in coding regions and in intergenic DNA without promoters. This trend is present regardless of the absolute levels of the structural parameters, and we suggest that this may be related to the requirement for helix unwinding during initiation of transcription, or perhaps to the previously observed

  4. Differentiation of Crohn’s Disease-Associated Isolates from Other Pathogenic Escherichia coli by Fimbrial Adhesion under Shear Force

    PubMed Central

    Szunerits, Sabine; Zagorodko, Oleksandr; Cogez, Virginie; Dumych, Tetiana; Chalopin, Thibaut; Alvarez Dorta, Dimitri; Sivignon, Adeline; Barnich, Nicolas; Harduin-Lepers, Anne; Larroulet, Iban; Yanguas Serrano, Aritz; Siriwardena, Aloysius; Pesquera, Amaia; Zurutuza, Amaia; Gouin, Sébastien G.; Boukherroub, Rabah; Bouckaert, Julie

    2016-01-01

    Shear force exerted on uropathogenic Escherichia coli adhering to surfaces makes type-1 fimbriae stretch out like springs to catch on to mannosidic receptors. This mechanism is initiated by a disruption of the quaternary interactions between the lectin and the pilin of the two-domain FimH adhesin and transduces allosterically to the mannose-binding pocket of FimH to increase its affinity. Mannose-specific adhesion of 14 E. coli pathovars was measured under flow, using surface plasmon resonance detection on functionalized graphene-coated gold interfaces. Increasing the shear had important differential consequences on bacterial adhesion. Adherent-invasive E. coli, isolated from the feces and biopsies of Crohn’s disease patients, consistently changed their adhesion behavior less under shear and displayed lower SPR signals, compared to E. coli opportunistically infecting the urinary tract, intestines or loci of knee and hip prostheses. We exemplified this further with the extreme behaviors of the reference strains UTI89 and LF82. Whereas their FimA major pilins have identical sequences, FimH of LF82 E. coli is marked by the Thr158Pro mutation. Positioned in the inter-domain region known to carry hot spots of mutations in E. coli pathotypes, residue 158 is indicated to play a structural role in the allosteric regulation of type-1 fimbriae-mediated bacterial adhesion. PMID:27043645

  5. Regulation of alcohol fermentation by Escherichia coli

    SciTech Connect

    Clark, D.P.

    1986-03-01

    The purpose of this project is to elucidate the way in which the fermentative synthesis of ethanol is regulated in the facultative anaerobe Escherichia coli. Focus is on the two final steps in alcohol synthesis, which are catalyzed by alcohol dehydrogenase and acetaldehyde CoA dehydrogenase. We have isolated a series of mutations affecting the expression of these enzymes. Some of these mutations are in the structural genes for these enzymes; others affect the regulation of the adh operon. We have recently cloned the genes coding for these enzymes and are now studying the effect of multiple copies of the adh gene on fermentative growth and its regulation. A recently invented technique, proton suicide has allowed the selection of a variety of novel mutants affecting fermentation which are presently being characterized. We have isolated a comprehensive collection of operon fusions in which the lacZ structural gene is fused to promoters that are inactive aerobically but active anaerobically. Although these genes (like adh) are only expressed under anaerobic conditions, the level of induction varies from two-fold to nearly 100-fold. The nitrogen source, medium pH, nature of the buffer, presence of alternative electron acceptors (e.g., nitrate), and other factors exert a great effect on the expression of many of these genes. In the near future we will investigate control mechanisms common to the adh operon and other anaerobically regulated genes.

  6. Genotoxicity of Graphene in Escherichia coli

    NASA Astrophysics Data System (ADS)

    Sharma, Ananya

    Rapid advances in nanotechnology necessitate assessment of the safety of nanomaterials in the resulting products and applications. One key nanomaterial attracting much interest in many areas of science and technology is graphene. Graphene is a one atom thick carbon allotrope arranged in a two-dimensional honeycomb lattice. In addition to being extremely thin, graphene has several extraordinary physical properties such as its exceptional mechanical strength, thermal stability, and high electrical conductivity. Graphene itself is relatively chemically inert and therefore pristine graphene must undergo a process called functionalization, which is combination of chemical and physical treatments that change the properties of graphene, to make it chemically active. Functionalization of graphene is of crucial importance as the end application of graphene depends on proper functionalization. In the field of medicine, graphene is currently a nanomaterial of high interest for building biosensors, DNA transistors, and probes for cancer detection. Despite the promising applications of graphene in several areas of biomedicine, there have been only few studies in recent years that focus on evaluating cytotoxicity of graphene on cells, and almost no studies that investigate how graphene exposure affects cellular genetic material. Therefore, in this study we used a novel approach to evaluate the genotoxicity, i.e., the effects of graphene on DNA, using Escherichia coli as a prokaryotic model organism.

  7. Shiga toxin-producing Escherichia coli

    PubMed Central

    Etcheverría, Analía Inés; Padola, Nora Lía

    2013-01-01

    Shiga toxin-producing Escherichia coli (STEC) cause hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS) in humans. Outbreaks are linked to bovine food sources. STEC O157:H7 has been responsible for the most severe outbreaks worldwide. However, non-O157 serotypes have emerged as important enteric pathogens in several countries. The main virulence factor of STEC is the production of Shiga toxins 1 and 2. Additional virulence markers are a plasmid-encoded enterohemolysin (ehxA), an autoagglutinating adhesin (Saa), a catalase-peroxidase (katP), an extracellular serine protease (espP), a zinc metalloprotease (stcE), a subtilase cytotoxin (subAB), among others. Other virulence factors are intimin and adhesins that had a roll in the adherence of STEC to bovine colon. This review focuses on the virulence traits of STEC and especially on those related to the adhesion to bovine colon. The known of the interaction between STEC and the bovine host is crucial to develop strategies to control cattle colonization. PMID:23624795

  8. A surprising sweetener from enteropathogenic Escherichia coli

    PubMed Central

    Pearson, Jaclyn S; Hartland, Elizabeth L

    2014-01-01

    Infections with enteropathogenic Escherichia coli (EPEC) are remarkably devoid of gut inflammation and necrotic damage compared to infections caused by invasive pathogens such as Salmonella and Shigella. Recently, we observed that EPEC blocks cell death using the type III secretion system (T3SS) effector NleB. NleB mediated post-translational modification of death domain containing adaptor proteins by the covalent attachment of N-acetylglucosamine (GlcNAc) to a conserved arginine in the death domain.  N-linked glycosylation of arginine has not previously been reported in mammalian cell biology and the precise biochemistry of this modification is not yet defined. Although the addition of a single GlcNAc to arginine is a seemingly slight alteration, the impact of NleB is considerable as arginine in this location is critical for death domain interactions and death receptor induced apoptosis. Hence, by blocking cell death, NleB promotes enterocyte survival and thereby prolongs EPEC attachment to the gut epithelium. PMID:25536377

  9. A surprising sweetener from enteropathogenic Escherichia coli.

    PubMed

    Pearson, Jaclyn S; Hartland, Elizabeth L

    2014-01-01

    Infections with enteropathogenic Escherichia coli (EPEC) are remarkably devoid of gut inflammation and necrotic damage compared to infections caused by invasive pathogens such as Salmonella and Shigella. Recently, we observed that EPEC blocks cell death using the type III secretion system (T3SS) effector NleB. NleB mediated post-translational modification of death domain containing adaptor proteins by the covalent attachment of N-acetylglucosamine (GlcNAc) to a conserved arginine in the death domain.  N-linked glycosylation of arginine has not previously been reported in mammalian cell biology and the precise biochemistry of this modification is not yet defined. Although the addition of a single GlcNAc to arginine is a seemingly slight alteration, the impact of NleB is considerable as arginine in this location is critical for death domain interactions and death receptor induced apoptosis. Hence, by blocking cell death, NleB promotes enterocyte survival and thereby prolongs EPEC attachment to the gut epithelium.

  10. Colonization factors of enterotoxigenic Escherichia coli.

    PubMed

    Madhavan, T P Vipin; Sakellaris, Harry

    2015-01-01

    Enterotoxigenic Escherichia coli (ETEC) is a major cause of life-threatening diarrheal disease around the world. The major aspects of ETEC virulence are colonization of the small intestine and the secretion of enterotoxins which elicit diarrhea. Intestinal colonization is mediated, in part, by adhesins displayed on the bacterial cell surface. As colonization of the intestine is the critical first step in the establishment of an infection, it represents a potential point of intervention for the prevention of infections. Therefore, colonization factors (CFs) have been important subjects of research in the field of ETEC virulence. Research in this field has revealed that ETEC possesses a large array of serologically distinct CFs that differ in composition, structure, and function. Most ETEC CFs are pili (fimbriae) or related fibrous structures, while other adhesins are simple outer membrane proteins lacking any macromolecular structure. This chapter reviews the genetics, structure, function, and regulation of ETEC CFs and how such studies have contributed to our understanding of ETEC virulence and opened up potential opportunities for the development of preventive and therapeutic interventions. PMID:25596032

  11. Eclipse period without sequestration in Escherichia coli.

    PubMed

    Olsson, Jan; Dasgupta, Santanu; Berg, Otto G; Nordström, Kurt

    2002-06-01

    The classical Meselson-Stahl density shift experiment was used to determine the length of the eclipse period in Escherichia coli, the minimum time period during which no new initiation is allowed from a newly replicated origin of chromosome replication, oriC. Populations of bacteria growing exponentially in heavy ((15)NH(4)+ and (13)C(6)-glucose) medium were shifted to light ((14)NH(4)+ and (12)C(6)-glucose) medium. The HH-, HL- and LL-DNA were separated by CsCl density gradient centrifugation, and their relative amounts were determined using radioactive gene-specific probes. The eclipse period, estimated from the kinetics of conversion of HH-DNA to HL- and LL-DNA, turned out to be 0.60 generation times for the wild-type strain. This was invariable for widely varying doubling times (35, 68 and 112 min) and was independent of the chromosome locus at which the eclipse period was measured. For strains with seqA, dam and damseqA mutants, the length of the eclipse period was 0.16, 0.40 and 0.32 generation times respectively. Thus, initiations from oriC were repressed for a considerable proportion of the generation time even when the sequestration function seemed to be severely compromised. The causal relationship between the length of the eclipse period and the synchrony of initiations from oriC is discussed.

  12. Biochemistry of homologous recombination in Escherichia coli.

    PubMed Central

    Kowalczykowski, S C; Dixon, D A; Eggleston, A K; Lauder, S D; Rehrauer, W M

    1994-01-01

    Homologous recombination is a fundamental biological process. Biochemical understanding of this process is most advanced for Escherichia coli. At least 25 gene products are involved in promoting genetic exchange. At present, this includes the RecA, RecBCD (exonuclease V), RecE (exonuclease VIII), RecF, RecG, RecJ, RecN, RecOR, RecQ, RecT, RuvAB, RuvC, SbcCD, and SSB proteins, as well as DNA polymerase I, DNA gyrase, DNA topoisomerase I, DNA ligase, and DNA helicases. The activities displayed by these enzymes include homologous DNA pairing and strand exchange, helicase, branch migration, Holliday junction binding and cleavage, nuclease, ATPase, topoisomerase, DNA binding, ATP binding, polymerase, and ligase, and, collectively, they define biochemical events that are essential for efficient recombination. In addition to these needed proteins, a cis-acting recombination hot spot known as Chi (chi: 5'-GCTGGTGG-3') plays a crucial regulatory function. The biochemical steps that comprise homologous recombination can be formally divided into four parts: (i) processing of DNA molecules into suitable recombination substrates, (ii) homologous pairing of the DNA partners and the exchange of DNA strands, (iii) extension of the nascent DNA heteroduplex; and (iv) resolution of the resulting crossover structure. This review focuses on the biochemical mechanisms underlying these steps, with particular emphases on the activities of the proteins involved and on the integration of these activities into likely biochemical pathways for recombination. Images PMID:7968921

  13. Oligosaccharide Binding in Escherichia coli Glycogen Synthase

    SciTech Connect

    Sheng, Fang; Yep, Alejandra; Feng, Lei; Preiss, Jack; Geiger, James H.

    2010-11-17

    Glycogen/starch synthase elongates glucan chains and is the key enzyme in the synthesis of glycogen in bacteria and starch in plants. Cocrystallization of Escherichia coli wild-type glycogen synthase (GS) with substrate ADPGlc and the glucan acceptor mimic HEPPSO produced a closed form of GS and suggests that domain-domain closure accompanies glycogen synthesis. Cocrystallization of the inactive GS mutant E377A with substrate ADPGlc and oligosaccharide results in the first oligosaccharide-bound glycogen synthase structure. Four bound oligosaccharides are observed, one in the interdomain cleft (G6a) and three on the N-terminal domain surface (G6b, G6c, and G6d). Extending from the center of the enzyme to the interdomain cleft opening, G6a mostly interacts with the highly conserved N-terminal domain residues lining the cleft of GS. The surface-bound oligosaccharides G6c and G6d have less interaction with enzyme and exhibit a more curled, helixlike structural arrangement. The observation that oligosaccharides bind only to the N-terminal domain of GS suggests that glycogen in vivo probably binds to only one side of the enzyme to ensure unencumbered interdomain movement, which is required for efficient, continuous glucan-chain synthesis.

  14. Regulation of Glutamine Transport in Escherichia coli.

    PubMed Central

    Willis, R C; Iwata, K K; Furlong, C E

    1975-01-01

    The formation of the high-affinity (Km equal to 0.2 muM) L-glutamine transport system of Escherichia coli strain 7 (Lin) appears to be subject to the same major control as the glutamine synthetase (EC 6.3.1.2) of this gram-negative organism. Culture of cells under nitrogen-limited conditions provides maximum derepression of both the glutamine synthetase and the glutamine transport system. Nutritional conditions providing a rich supply of ammonium salts or available sources of nitrogen, i.e., conditions which repress the formation of glutamine synthetase, provide three- and 20-fold repression, respectively, of the glutamine transport system. Culture of cells with glutamine supplements of 2 mM does not increase the repression of high-affinity glutamine transport system beyond the level observed in the absence of glutamine. A second kinetically distinct low-affinity component of glutamine. A second kinetically distinct low-affinity component of glutamine uptake is observed in cells cultured with a glutamine-depleted nutrient broth. This second component is associated with the appearance of glutaminase A (EC 3.5.1.2) and asparaginase I (EC 3.5.1.1), a periplasmic enzyme. Parallel changes were observed in the levels of the high-affinity glutamine transport system and the glutamine synthetase when cells were cultured with the carbon sources: glucose, glycerol, or succinate. PMID:238938

  15. Curli expression of enterotoxigenic Escherichia coli.

    PubMed

    Szabó, E; Skedsmo, A; Sonnevend, A; Al-Dhaheri, K; Emody, L; Usmani, A; Pál, T

    2005-01-01

    One hundred and four enterotoxin producing Escherichia coli strains of wide geographical origin were tested for the expression of curli fimbriae by transmission electronmicroscopy and by ELISA using curli-specific antibodies, as well as for the presence of curli-specific gene sequences by PCR. All isolates, irrespective of the production of the fimbriae, carried sequences specific for the structure (csgA) and for one of the regulator genes (crl) of curli expression, respectively. Curli fimbriae were detected in 56 strains (53.8 %). Thirty-six strains expressed curli only when growing at 30 degrees C, 4 isolates were weakly curliated at 37 degrees C only, while on 16 strains curli was observed at both temperatures. On isolates carrying curli at both temperatures the expression of the fimbria was significantly stronger at 30 degrees C than at 37 degrees C. Curli proficiency significantly, but not completely, correlated with the binding of the Congo Red dye. The expression of curli did not confer epithelial cell invasiveness to ETEC strains but, once expressed at 30 degrees C, it facilitated the adherence of the bacteria to plastic surfaces. Curli present in more than half of the ETEC strains and expressed preferentially at low temperatures could be a factor facilitating the environmental survival of this food- and water-borne pathogen.

  16. Phylogenetic grouping and pathotypic comparison of urine and fecal Escherichia coli isolates from children with urinary tract infection.

    PubMed

    Navidinia, Masoumeh; Peerayeh, Shahin Najar; Fallah, Fatemeh; Bakhshi, Bita; Sajadinia, Raheleh Sadat

    2014-01-01

    The aim of this study was to investigate the phylogenetic background and to assess hlyD (involved in the secretion of haemolysin A) and intI1 (encoding a class 1 integrase) in Escherichia coli isolates derived from urinary and fecal specimens. A total of 200 E. coli isolates was collected from patients presenting with urinary tract infection (UTI) during September 2009 to September 2010 and screened for hlyD and intI1 genes by polymerase chain reaction (PCR). Phylogenetic analysis showed that E. coli is composed of four main phylogenetic groups (A, B1, B2 and D) and that uropathogenic E. coli (UPEC) isolates mainly belong to groups B2 (54%) and D (34%) whereas group A (44%) and D (26%) are predominant among commensal E. coli isolates. In this study, hlyD was present in 26% of UPEC and 2% of commensal E. coli isolates. However, hemolytic activity was detected for 42% of UPEC and 6% of commensal E. coli isolates (p < 0.05). intI1 gene was more frequently expressed in UPEC (24%) in comparison with commensal E. coli isolates (12%). Resistance to aztreonam, co-trimoxazole and cefpodoxime were frequently found among UPEC isolates whereas commensal E. coli isolates were commonly resistant to co-trimoxazole, nalidixic acid and cefotaxime. Concluding, a considerable difference between UPEC and commensal E. coli isolates was observed regarding their phylogenetic groups, presence of class 1 integron and hlyD gene, hemolysin activity and resistance pattern. The detection of class 1 integrons and hlyD gene was higher among UPEC compared with commensal E. coli isolates. These findings may contribute for a better understanding of the factors involved in the pathogenesis of UPEC.

  17. Phylogenetic grouping and pathotypic comparison of urine and fecal Escherichia coli isolates from children with urinary tract infection

    PubMed Central

    Navidinia, Masoumeh; Peerayeh, Shahin Najar; Fallah, Fatemeh; Bakhshi, Bita; Sajadinia, Raheleh Sadat

    2014-01-01

    The aim of this study was to investigate the phylogenetic background and to assess hlyD (involved in the secretion of haemolysin A) and intI1 (encoding a class 1 integrase) in Escherichia coli isolates derived from urinary and fecal specimens. A total of 200 E. coli isolates was collected from patients presenting with urinary tract infection (UTI) during September 2009 to September 2010 and screened for hlyD and intI1 genes by polymerase chain reaction (PCR). Phylogenetic analysis showed that E. coli is composed of four main phylogenetic groups (A, B1, B2 and D) and that uropathogenic E. coli (UPEC) isolates mainly belong to groups B2 (54%) and D (34%) whereas group A (44%) and D (26%) are predominant among commensal E. coli isolates. In this study, hlyD was present in 26% of UPEC and 2% of commensal E. coli isolates. However, hemolytic activity was detected for 42% of UPEC and 6% of commensal E. coli isolates (p < 0.05). intI1 gene was more frequently expressed in UPEC (24%) in comparison with commensal E. coli isolates (12%). Resistance to aztreonam, co-trimoxazole and cefpodoxime were frequently found among UPEC isolates whereas commensal E. coli isolates were commonly resistant to co-trimoxazole, nalidixic acid and cefotaxime. Concluding, a considerable difference between UPEC and commensal E. coli isolates was observed regarding their phylogenetic groups, presence of class 1 integron and hlyD gene, hemolysin activity and resistance pattern. The detection of class 1 integrons and hlyD gene was higher among UPEC compared with commensal E. coli isolates. These findings may contribute for a better understanding of the factors involved in the pathogenesis of UPEC. PMID:25242935

  18. Enterotoxigenic Escherichia coli multilocus sequence types in Guatemala and Mexico.

    PubMed

    Nicklasson, Matilda; Klena, John; Rodas, Claudia; Bourgeois, August Louis; Torres, Olga; Svennerholm, Ann Mari; Sjoling, Asa

    2010-01-01

    The genetic backgrounds of 24 enterotoxigenic Escherichia coli (ETEC) strains from Mexico and Guatemala expressing heat-stable toxin (ST) and coli surface antigen 6 (CS6) were analyzed. US travelers to these countries and resident children in Guatemala were infected by ETEC strains of sequence type 398, expressing STp and carrying genetically identical CS6 sequences.

  19. Complete Draft Genome Sequence of Escherichia coli JF733

    PubMed Central

    Kleiner, Gabriele R. M.; Wibberg, Daniel; Winkler, Anika; Wertz, John E.; Friehs, Karl

    2016-01-01

    Escherichia coli JF733 is a strain with a long history in research on membrane proteins and processes. However, tracing back the strain development raises some questions concerning the correct genotype of JF733. Here, we present the complete draft genome of E. coli JF733 in order to resolve any remaining uncertainties. PMID:27103723

  20. Nisin stimulates oxygen consumption by Staphylococcus aureus and Escherichia coli.

    PubMed Central

    Carneiro de Melo, A M; Cook, G M; Miles, R J; Poole, R K

    1996-01-01

    Nisin stimulated oxygen consumption by nongrowing, glucose-metabolizing Staphylococcus aureus and Escherichia coli cells, indicating a protonophore mode of action. A similar stimulation in E. coli cells osmotically stressed to disrupt the outer cell membrane confirmed the cytoplasmic membrane as the site of nisin action and showed that nisin uptake was not prevented by the outer membrane. PMID:8633884

  1. Structure and function of enterotoxigenic Escherichia coli fimbriae from differing assembly pathways.

    PubMed

    Mortezaei, Narges; Epler, Chelsea R; Shao, Paul P; Shirdel, Mariam; Singh, Bhupender; McVeigh, Annette; Uhlin, Bernt Eric; Savarino, Stephen J; Andersson, Magnus; Bullitt, Esther

    2015-01-01

    Pathogenic enterotoxigenic Escherichia coli (ETEC) are the major bacterial cause of diarrhea in young children in developing countries and in travelers, causing significant mortality in children. Adhesive fimbriae are a prime virulence factor for ETEC, initiating colonization of the small intestinal epithelium. Similar to other Gram-negative bacteria, ETEC express one or more diverse fimbriae, some assembled by the chaperone-usher pathway and others by the alternate chaperone pathway. Here, we elucidate structural and biophysical aspects and adaptations of each fimbrial type to its respective host niche. CS20 fimbriae are compared with colonization factor antigen I (CFA/I) fimbriae, which are two ETEC fimbriae assembled via different pathways, and with P-fimbriae from uropathogenic E. coli. Many fimbriae unwind from their native helical filament to an extended linear conformation under force, thereby sustaining adhesion by reducing load at the point of contact between the bacterium and the target cell. CFA/I fimbriae require the least force to unwind, followed by CS20 fimbriae and then P-fimbriae, which require the highest unwinding force. We conclude from our electron microscopy reconstructions, modeling and force spectroscopy data that the target niche plays a central role in the biophysical properties of fimbriae that are critical for bacterial pathophysiology. PMID:25355550

  2. Host-specific induction of Escherichia coli fitness genes during human urinary tract infection.

    PubMed

    Subashchandrabose, Sargurunathan; Hazen, Tracy H; Brumbaugh, Ariel R; Himpsl, Stephanie D; Smith, Sara N; Ernst, Robert D; Rasko, David A; Mobley, Harry L T

    2014-12-23

    Uropathogenic Escherichia coli (UPEC) is the predominant etiological agent of uncomplicated urinary tract infection (UTI), manifested by inflammation of the urinary bladder, in humans and is a major global public health concern. Molecular pathogenesis of UPEC has been primarily examined using murine models of UTI. Translational research to develop novel therapeutics against this major pathogen, which is becoming increasingly antibiotic resistant, requires a thorough understanding of mechanisms involved in pathogenesis during human UTIs. Total RNA-sequencing (RNA-seq) and comparative transcriptional analysis of UTI samples to the UPEC isolates cultured in human urine and laboratory medium were used to identify novel fitness genes that were specifically expressed during human infection. Evidence for UPEC genes involved in ion transport, including copper efflux, nickel and potassium import systems, as key fitness factors in uropathogenesis were generated using an experimental model of UTI. Translational application of this study was investigated by targeting Cus, a bacterial copper efflux system. Copper supplementation in drinking water reduces E. coli colonization in the urinary bladder of mice. Additionally, our results suggest that anaerobic processes in UPEC are involved in promoting fitness during UTI in humans. In summary, RNA-seq was used to establish the transcriptional signature in UPEC during naturally occurring, community acquired UTI in women and multiple novel fitness genes used by UPEC during human infection were identified. The repertoire of UPEC genes involved in UTI presented here will facilitate further translational studies to develop innovative strategies against UTI caused by UPEC.

  3. YjjQ Represses Transcription of flhDC and Additional Loci in Escherichia coli

    PubMed Central

    Wiebe, Helene; Gürlebeck, Doreen; Groß, Jana; Dreck, Katrin; Pannen, Derk; Ewers, Christa; Wieler, Lothar H.

    2015-01-01

    ABSTRACT The presumptive transcriptional regulator YjjQ has been identified as being virulence associated in avian pathogenic Escherichia coli (APEC). In this work, we characterize YjjQ as transcriptional repressor of the flhDC operon, encoding the master regulator of flagellar synthesis, and of additional loci. The latter include gfc (capsule 4 synthesis), ompC (outer membrane porin C), yfiRNB (regulated c-di-GMP synthesis), and loci of poorly defined function (ybhL and ymiA-yciX). We identify the YjjQ DNA-binding sites at the flhDC and gfc promoters and characterize a DNA-binding sequence motif present at all promoters found to be repressed by YjjQ. At the flhDC promoter, the YjjQ DNA-binding site overlaps the RcsA-RcsB DNA-binding site. RcsA-RcsB likewise represses the flhDC promoter, but the repression by YjjQ and that by RcsA-RcsB are independent of each other. These data suggest that YjjQ is an additional regulator involved in the complex control of flhDC at the level of transcription initiation. Furthermore, we show that YjjQ represses motility of the E. coli K-12 laboratory strain and of uropathogenic E. coli (UPEC) strains CFT073 and 536. Regulation of flhDC, yfiRNB, and additional loci by YjjQ may be features relevant for pathogenicity. IMPORTANCE Escherichia coli is a commensal and pathogenic bacterium causing intra- and extraintestinal infections in humans and farm animals. The pathogenicity of E. coli strains is determined by their particular genome content, which includes essential and associated virulence factors that control the cellular physiology in the host environment. However, the gene pools of commensal and pathogenic E. coli are not clearly differentiated, and the function of virulence-associated loci needs to be characterized. In this study, we characterize the function of yjjQ, encoding a transcription regulator that was identified as being virulence associated in avian pathogenic E. coli (APEC). We characterize YjjQ as transcriptional

  4. Prevalence of Class D Carbapenemases among Extended-Spectrum β-Lactamases Producing Escherichia coli Isolates from Educational Hospitals in Shahrekord

    PubMed Central

    Damavandi, Mohammad-Sadegh; Latif Pour, Mohammad

    2016-01-01

    Introduction Extended-spectrum β-lactamases (ESBLs) are a set of plasmid-borne, various and quickly evolving enzymes that are a main therapeutic issue now-a-days for inpatient and outpatient treatment. Aim The aim of this study was to determine multi-drug resistance (MDR) and ESBLs producing E. coli strains, prevalence of class D Carbapenemases among ESBLs producing Escherichia coli isolates from educational hospitals in Shahrekord, Iran. Materials and Methods Uropathogenic Escherichia coli strains were isolated from patients with Urinary Tract Infections (UTIs). The agar disc diffusion test was used to characterize the antimicrobial sensitivity of the E. coli isolates. The ESBL positive strains were identified by phenotypic double-disk synergy test, by third-generation cephalosporin in combination with or without clavulanic acid. Multiplex PCR was carried out for detection of the three families of OXA-type carbapenamases including OXA-23, OXA-24, and OXA-48 in E. coli strains. Results All bacterial isolates were susceptible to meropenem. Ninety isolates produced ESBL, 55 E. coli isolates from inpatients, and 35 isolates from outpatients, with a significant association (p< 0.05). The prevalence of OXA-23, OXA-24, and OXA-48 in the ESBLs producing isolates was respectively 21%, 18%, and 11% for inpatients, and 10%, 8%, and 6% for outpatients. Conclusion ESBL-producing E. coli isolates are also a major threat in the clinical setting. The findings of this study indicated the high occurrence of ESBLs and multiple antibiotic resistance in E. coli isolates. PMID:27462579

  5. The function of ubiquinone in Escherichia coli

    PubMed Central

    Cox, G. B.; Newton, N. A.; Gibson, F.; Snoswell, A. M.; Hamilton, J. A.

    1970-01-01

    1. The function of ubiquinone in Escherichia coli was studied by using whole cells and membrane preparations of normal E. coli and of a mutant lacking ubiquinone. 2. The mutant lacking ubiquinone, strain AN59 (Ubi−), when grown under aerobic conditions, gave an anaerobic type of growth yield and produced large quantities of lactic acid, indicating that ubiquinone plays a vital role in electron transport. 3. NADH and lactate oxidase activities in membranes from strain AN59 (Ubi−) were greatly impaired and activity was restored by the addition of ubiquinone (Q-1). 4. Comparison of the percentage reduction of flavin, cytochrome b1 and cytochrome a2 in the aerobic steady state in membranes from the normal strain (AN62) and strain AN59 (Ubi−) and the effect of respiratory inhibitors on these percentages in membranes from strain AN62 suggest that ubiquinone functions at more than one site in the electron-transport chain. 5. Membranes from strain AN62, in the absence of substrate, showed an electron-spin-resonance signal attributed to ubisemiquinone. The amount of reduced ubiquinone (50%) found after rapid solvent extraction is consistent with the existence of ubiquinone in membranes as a stabilized ubisemiquinone. 6. The effects of piericidin A on membranes from strain AN62 suggest that this inhibitor acts at the ubiquinone sites: thus inhibition of electron transport is reversed by ubiquinone (Q-1); the aerobic steady-state oxidation–reduction levels of flavins and cytochrome b1 in the presence of the inhibitor are raised to values approximating those found in the membranes of strain AN59 (Ubi−); the inhibitor rapidly eliminates the electron-spin-resonance signal attributed to ubisemiquinone and allows slow oxidation of endogenous ubiquinol in the absence of substrate and prevents reduction of ubiquinone in the presence of substrate. It is concluded that piericidin A separates ubiquinone from the remainder of the electron-transport chain. 7. A scheme is

  6. Lysis of Escherichia coli mutants by lactose.

    PubMed

    Alexander, J K

    1979-11-01

    Growth of Escherichia coli strain MM6-13 (ptsI suc lacI sup), which as a suppressor of the succinate-negative phenotype, was inhibited by lactose. Cells growing in yeast extract-tryptone-sodium chloride medium (LB broth) were lysed upon the addition of lactose. In Casamino Acids-salts medium, lactose inhibited growth, but due to the high K+ content no lysis occurred. Lysis required high levels of beta-galctosidase and lactose transport activity. MM6, the parental strain of MM6-13, has lower levels of both of these activities and was resistant to lysis under these conditions. When MM6 was grown in LB broth with exogenous cyclic adenosine monophosphate, however, beta-galactosidase and lactose transport activities were greatly increased, and lysis occurred upon the addition of lactose. Resting cells of both MM6 and MM6-13 were lysed by lactose in buffers containing suitable ions. In the presence of MG2+, lysis was enhanced by 5 mM KCl and 100 mM NaCl. Higher slat concentrations (50 mM KCl or 200 mM NaCl) provided partial protection from lysis. In the absence of Mg2+, lysis occurred without KCl. Lactose-dependent lysis occurred in buffers containing anions such as sulafte, chloride, phosphate, or citrate; however, thiocyanate or acetate protected the cells from lysis. These data indicate that both cations and anions, as well as the levels of lactose transport and beta-galactosidase activity, are important in lysis.

  7. Shiga toxin-producing Escherichia coli.

    PubMed

    Smith, James L; Fratamico, Pina M; Gunther, Nereus W

    2014-01-01

    In the United States, it is estimated that non-O157 Shiga toxin-producing Escherichia coli (STEC) cause more illnesses than STEC O157:H7, and the majority of cases of non-O157 STEC infections are due to serogroups O26, O45, O103, O111, O121, and O145, referred to as the top six non-O157 STEC. The diseases caused by non-O157 STEC are generally milder than those induced by O157 STEC; nonetheless, non-O157 STEC strains have also been associated with serious illnesses such as hemorrhagic colitis and hemolytic uremic syndrome, as well as death. Ruminants, particularly cattle, are reservoirs for both O157 and non-O157 STEC, which are transmitted to humans by person-to-person or animal contact and by ingestion of food or water contaminated with animal feces. Improved strategies to control STEC colonization and shedding in cattle and contamination of meat and produce are needed. In general, non-O157 STEC respond to stresses such as acid, heat, and other stresses induced during food preparation similar to O157 STEC. Similar to O157:H7, the top six non-O157 STEC are classified as adulterants in beef by the USDA Food Safety and Inspection Service, and regulatory testing for these pathogens began in June 2012. Due to the genetic and phenotypic variability of non-O157 STEC strains, the development of accurate and reliable methods for detection and isolation of these pathogens has been challenging. Since the non-O157 STEC are responsible for a large portion of STEC-related illnesses, more extensive studies on their physiology, genetics, pathogenicity, and evolution are needed in order to develop more effective control strategies.

  8. Systematic Mutagenesis of the Escherichia coli Genome†

    PubMed Central

    Kang, Yisheng; Durfee, Tim; Glasner, Jeremy D.; Qiu, Yu; Frisch, David; Winterberg, Kelly M.; Blattner, Frederick R.

    2004-01-01

    A high-throughput method has been developed for the systematic mutagenesis of the Escherichia coli genome. The system is based on in vitro transposition of a modified Tn5 element, the Sce-poson, into linear fragments of each open reading frame. The transposon introduces both positive (kanamycin resistance) and negative (I-SceI recognition site) selectable markers for isolation of mutants and subsequent allele replacement, respectively. Reaction products are then introduced into the genome by homologous recombination via the λRed proteins. The method has yielded insertion alleles for 1976 genes during a first pass through the genome including, unexpectedly, a number of known and putative essential genes. Sce-poson insertions can be easily replaced by markerless mutations by using the I-SceI homing endonuclease to select against retention of the transposon as demonstrated by the substitution of amber and/or in-frame deletions in six different genes. This allows a Sce-poson-containing gene to be specifically targeted for either designed or random modifications, as well as permitting the stepwise engineering of strains with multiple mutations. The promiscuous nature of Tn5 transposition also enables a targeted gene to be dissected by using randomly inserted Sce-posons as shown by a lacZ allelic series. Finally, assessment of the insertion sites by an iterative weighted matrix algorithm reveals that these hyperactive Tn5 complexes generally recognize a highly degenerate asymmetric motif on one end of the target site helping to explain the randomness of Tn5 transposition. PMID:15262929

  9. Very slow growth of Escherichia coli.

    PubMed Central

    Chesbro, W; Evans, T; Eifert, R

    1979-01-01

    A recycling fermentor (a chemostat with 100% biomass feedback) was used to study glucose-limited behavior of Escherichia coli B. The expectation from mass transfer analysis that growth would asymptotically approach a limit mass determined by the glucose provision rate (GPR) and the culture's maintenance requirement was not met. Instead, growth proceeded at progressively lower rates through three distinct phases. After the fermentor was seeded, but before glucose became limiting, growth followed the usual, exponential path (phase 1). About 12 h postseeding, residual glucose in the fermentor fell below 1 microgram . ml-1 and the growth rate (dx/dt) became constant and a linear function of GPR (phase 2). The specific growth rate, mu, therefore fell continuously throughout the phase. Biomass yield and glucose assimilation (13%) were near the level for exponential growth, however, and independent of GPR over a broad range. At a critical specific growth rate (0.04 h-1 for this strain), phase 2 ended abruptly and phase 3 commenced. In phase 3, the growth rate was again constant, although lower than in phase 2, so that mu continued to fall, but growth rates and yields were praboloid functions of GPR. They were never zero, however, at any positive value of GPR. By inference, the fraction of metabolic energy used for maintenance functions is constant for a given GPR, although different for phases 2 and 3, and independent of biomass. In both phases 2 and 3, orcinol, diphenylamine, and Lowry reactive materials were secreted at near-constant rates such that over 50% as much biosynthetic mass was secreted as was retained by the cells. Images PMID:378981

  10. The Melibiose Transporter of Escherichia coli

    PubMed Central

    Fuerst, Oliver; Lin, Yibin; Granell, Meritxell; Leblanc, Gérard; Padrós, Esteve; Lórenz-Fonfría, Víctor A.; Cladera, Josep

    2015-01-01

    We examine the role of Lys-377, the only charged residue in helix XI, on the functional mechanism of the Na+-sugar melibiose symporter from Escherichia coli. Intrinsic fluorescence, FRET, and Fourier transform infrared difference spectroscopy reveal that replacement of Lys-377 with either Cys, Val, Arg, or Asp disables both Na+ and melibiose binding. On the other hand, molecular dynamics simulations extending up to 200–330 ns reveal that Lys-377 (helix XI) interacts with the anionic side chains of two of the three putative ligands for cation binding (Asp-55 and Asp-59 in helix II). When Asp-59 is protonated during the simulations, Lys-377 preferentially interacts with Asp-55. Interestingly, when a Na+ ion is positioned in the Asp-55-Asp-59 environment, Asp-124 in helix IV (a residue essential for melibiose binding) reorients and approximates the Asp-55-Asp-59 pair, and all three acidic side chains act as Na+ ligands. Under these conditions, the side chain of Lys-377 interacts with the carboxylic moiety of these three Asp residues. These data highlight the crucial role of the Lys-377 residue in the spatial organization of the Na+ binding site. Finally, the analysis of the second-site revertants of K377C reveals that mutation of Ile-22 (in helix I) preserves Na+ binding, whereas that of melibiose is largely abolished according to spectroscopic measurements. This amino acid is located in the border of the sugar-binding site and might participate in sugar binding through apolar interactions. PMID:25971963

  11. An adhesive protein capsule of Escherichia coli.

    PubMed Central

    Orskov, I; Birch-Andersen, A; Duguid, J P; Stenderup, J; Orskov, F

    1985-01-01

    The nature of the adhesive capacity of three hemagglutinating Escherichia coli strains that had earlier been described as nonfimbriated was studied. The strains that were isolated from human disease adhered to human buccal and urinary tract epithelial cells, an adhesion that was not inhibited by D-mannose. By crossed immunoelectrophoresis it was shown that the three strains produced a common antigen, Z1, developed after growth at 37 degrees C but not 18 degrees C. One of the strains produced an additional antigen, Z2, of almost the same electrophoretic mobility in crossed immunoelectrophoresis. A mutant of this strain deficient of its polysaccharide K antigen had maintained the adhesive capacity, indicating that the K antigen was not responsible for adhesion. A further mutant of the acapsular mutant produced a strongly reduced amount of the Z antigens and had lost the ability to adhere. The Z1 (and Z2?) antigens were therefore deemed to be responsible for adhesion. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis of extracts of cells of the three strains, a heavy Coomassie-blue stained line was seen, indicating the presence of a protein subunit of molecular weight slightly above 14,400. By immunoblotting with absorbed antiserum, it was shown that this protein was the same as that detected by crossed immunoelectrophoresis. Protease from Streptomyces griseus, but not trypsin, digested the protein. Heating to 100 degrees C did not affect it. By immunoelectron microscopy of embedded and sectioned bacteria that had first been treated with specific antisera and ferritin-labeled antirabbit immunoglobulin, the protein adhesin-antibody complex was found to surround the bacteria as a heavy capsule. After negative staining with uranylacetate (pH approximately 4), the capsule appeared as a mesh of very fine filaments. The possible role of this capsule in the pathogenesis of disease is discussed. Images PMID:2856913

  12. Type 1 Fimbriae Contribute to Catheter-Associated Urinary Tract Infections Caused by Escherichia coli

    PubMed Central

    Maierl, Mario; Jörger, Michael; Krause, Robert; Berger, Daniela; Haid, Andrea; Tesic, Dijana; Zechner, Ellen L.

    2014-01-01

    Biofilm formation on catheters is thought to contribute to persistence of catheter-associated urinary tract infections (CAUTI), which represent the most frequent nosocomial infections. Knowledge of genetic factors for catheter colonization is limited, since their role has not been assessed using physicochemical conditions prevailing in a catheterized human bladder. The current study aimed to combine data from a dynamic catheterized bladder model in vitro with in vivo expression analysis for understanding molecular factors relevant for CAUTI caused by Escherichia coli. By application of the in vitro model that mirrors the physicochemical environment during human infection, we found that an E. coli K-12 mutant defective in type 1 fimbriae, but not isogenic mutants lacking flagella or antigen 43, was outcompeted by the wild-type strain during prolonged catheter colonization. The importance of type 1 fimbriae for catheter colonization was verified using a fimA mutant of uropathogenic E. coli strain CFT073 with human and artificial urine. Orientation of the invertible element (IE) controlling type 1 fimbrial expression in bacterial populations harvested from the colonized catheterized bladder in vitro suggested that the vast majority of catheter-colonizing cells (up to 88%) express type 1 fimbriae. Analysis of IE orientation in E. coli populations harvested from patient catheters revealed that a median level of ∼73% of cells from nine samples have switched on type 1 fimbrial expression. This study supports the utility of the dynamic catheterized bladder model for analyzing catheter colonization factors and highlights a role for type 1 fimbriae during CAUTI. PMID:24336940

  13. Type 1 fimbriae contribute to catheter-associated urinary tract infections caused by Escherichia coli.

    PubMed

    Reisner, Andreas; Maierl, Mario; Jörger, Michael; Krause, Robert; Berger, Daniela; Haid, Andrea; Tesic, Dijana; Zechner, Ellen L

    2014-03-01

    Biofilm formation on catheters is thought to contribute to persistence of catheter-associated urinary tract infections (CAUTI), which represent the most frequent nosocomial infections. Knowledge of genetic factors for catheter colonization is limited, since their role has not been assessed using physicochemical conditions prevailing in a catheterized human bladder. The current study aimed to combine data from a dynamic catheterized bladder model in vitro with in vivo expression analysis for understanding molecular factors relevant for CAUTI caused by Escherichia coli. By application of the in vitro model that mirrors the physicochemical environment during human infection, we found that an E. coli K-12 mutant defective in type 1 fimbriae, but not isogenic mutants lacking flagella or antigen 43, was outcompeted by the wild-type strain during prolonged catheter colonization. The importance of type 1 fimbriae for catheter colonization was verified using a fimA mutant of uropathogenic E. coli strain CFT073 with human and artificial urine. Orientation of the invertible element (IE) controlling type 1 fimbrial expression in bacterial populations harvested from the colonized catheterized bladder in vitro suggested that the vast majority of catheter-colonizing cells (up to 88%) express type 1 fimbriae. Analysis of IE orientation in E. coli populations harvested from patient catheters revealed that a median level of ∼73% of cells from nine samples have switched on type 1 fimbrial expression. This study supports the utility of the dynamic catheterized bladder model for analyzing catheter colonization factors and highlights a role for type 1 fimbriae during CAUTI.

  14. Drinking water and diarrhoeal disease due to Escherichia coli.

    PubMed

    Hunter, Paul R

    2003-06-01

    Escherichia coli has had a central place in water microbiology for decades as an indicator of faecal pollution. It is only relatively recently that the role of E. coli as pathogen, rather than indicator, in drinking water has begun to be stressed. Interest in the role of E. coli as a cause of diarrhoeal disease has increased because of the emergence of E. coli O157:H7 and other enterohaemorrhagic E. coli, due to the severity of the related disease. There are enterotoxigenic, enteropathogenic, enterohaemorrhagic, enteroinvasive, enteroaggregative and diffusely adherent strains of E. coli. Each type of E. coli causes diarrhoeal disease through different mechanisms and each causes a different clinical presentation. Several of the types cause diarrhoea by the elaboration of one or more toxins, others by some other form of direct damage to epithelial cells. This paper discusses each of these types in turn and also describes their epidemiology, with particular reference to whether they are waterborne or not.

  15. Rapid Sterilization of Escherichia coli by Solution Plasma Process

    NASA Astrophysics Data System (ADS)

    Andreeva, Nina; Ishizaki, Takahiro; Baroch, Pavel; Saito, Nagahiro

    2012-12-01

    Solution plasma (SP), which is a discharge in the liquid phase, has the potential for rapid sterilization of water without chemical agents. The discharge showed a strong sterilization performance against Escherichia coli bacteria. The decimal value (D value) of the reduction time for E. coli by this system with an electrode distance of 1.0 mm was estimated to be approximately 1.0 min. Our discharge system in the liquid phase caused no physical damage to the E. coli and only a small increase in the temperature of the aqueous solution. The UV light generated by the discharge was an important factor in the sterilization of E. coli.

  16. Intracellular Uropathogenic E. coli Exploits Host Rab35 for Iron Acquisition and Survival within Urinary Bladder Cells.

    PubMed

    Dikshit, Neha; Bist, Pradeep; Fenlon, Shannon N; Pulloor, Niyas Kudukkil; Chua, Christelle En Lin; Scidmore, Marci A; Carlyon, Jason A; Tang, Bor Luen; Chen, Swaine L; Sukumaran, Bindu

    2015-08-01

    Recurrent urinary tract infections (UTIs) caused by uropathogenic E. coli (UPEC) are common and morbid infections with limited therapeutic options. Previous studies have demonstrated that persistent intracellular infection of bladder epithelial cells (BEC) by UPEC contributes to recurrent UTI in mouse models of infection. However, the mechanisms employed by UPEC to survive within BEC are incompletely understood. In this study we aimed to understand the role of host vesicular trafficking proteins in the intracellular survival of UPEC. Using a cell culture model of intracellular UPEC infection, we found that the small GTPase Rab35 facilitates UPEC survival in UPEC-containing vacuoles (UCV) within BEC. Rab35 plays a role in endosomal recycling of transferrin receptor (TfR), the key protein responsible for transferrin-mediated cellular iron uptake. UPEC enhance the expression of both Rab35 and TfR and recruit these proteins to the UCV, thereby supplying UPEC with the essential nutrient iron. Accordingly, Rab35 or TfR depleted cells showed significantly lower intracellular iron levels and reduced ability to support UPEC survival. In the absence of Rab35, UPEC are preferentially trafficked to degradative lysosomes and killed. Furthermore, in an in vivo murine model of persistent intracellular infection, Rab35 also colocalizes with intracellular UPEC. We propose a model in which UPEC subverts two different vesicular trafficking pathways (endosomal recycling and degradative lysosomal fusion) by modulating Rab35, thereby simultaneously enhancing iron acquisition and avoiding lysosomal degradation of the UCV within bladder epithelial cells. Our findings reveal a novel survival mechanism of intracellular UPEC and suggest a potential avenue for therapeutic intervention against recurrent UTI.

  17. The Biology of the Escherichia coli Extracellular Matrix

    PubMed Central

    Hufnagel, David A.; DePas, William H.; Chapman, Matthew R.

    2015-01-01

    Chapter Summary Escherichia coli (E. coli) is one of the world’s best-characterized organisms, as it has been extensively studied for over a century. However, most of this work has focused on E. coli grown under laboratory conditions that do not faithfully simulate its natural environments. Therefore, the historical perspectives on E. coli physiology and life cycle are somewhat skewed toward experimental systems that feature E. coli growing logarithmically in a test tube. Typically a commensal bacterium, E. coli resides in the lower intestines of a slew of animals. Outside of the lower intestine, E. coli can adapt and survive in a very different set of environmental conditions. Biofilm formation allows E. coli to survive, and even thrive, in environments that do not support the growth of planktonic populations. E. coli can form biofilms virtually everywhere; in the bladder during a urinary tract infection, on in-dwelling medical devices, and outside of the host on plants and in the soil. The E. coli extracellular matrix, primarily composed of the protein polymer named curli and the polysaccharide cellulose, promotes adherence to organic and inorganic surfaces, and resistance to desiccation, the host immune system and other antimicrobials. The pathways that govern E. coli biofilm formation, cellulose production, and curli biogenesis will be discussed in this book chapter, which concludes with insights into the future of E. coli biofilm research and potential therapies. PMID:26185090

  18. Binding studies of antimicrobial peptides to Escherichia coli cells.

    PubMed

    Avitabile, Concetta; D'Andrea, Luca D; Saviano, Michele; Olivieri, Michele; Cimmino, Amelia; Romanelli, Alessandra

    2016-09-01

    Understanding the mechanism of action of antimicrobial peptides is pivotal to the design of new and more active peptides. In the last few years it has become clear that the behavior of antimicrobial peptides on membrane model systems does not always translate to cells; therefore the need to develop methods aimed at capturing details of the interactions of peptides with bacterial cells is compelling. In this work we analyzed binding of two peptides, namely temporin B and TB_KKG6A, to Escherichia coli cells and to Escherichia coli LPS. Temporin B is a natural peptide active against Gram positive bacteria but inactive against Gram negative bacteria, TB_KKG6A is an analogue of temporin B showing activity against both Gram positive and Gram negative bacteria. We found that binding to cells occurs only for the active peptide TB_KKG6A; stoichiometry and affinity constant of this peptide toward Escherichia coli cells were determined.

  19. Binding studies of antimicrobial peptides to Escherichia coli cells.

    PubMed

    Avitabile, Concetta; D'Andrea, Luca D; Saviano, Michele; Olivieri, Michele; Cimmino, Amelia; Romanelli, Alessandra

    2016-09-01

    Understanding the mechanism of action of antimicrobial peptides is pivotal to the design of new and more active peptides. In the last few years it has become clear that the behavior of antimicrobial peptides on membrane model systems does not always translate to cells; therefore the need to develop methods aimed at capturing details of the interactions of peptides with bacterial cells is compelling. In this work we analyzed binding of two peptides, namely temporin B and TB_KKG6A, to Escherichia coli cells and to Escherichia coli LPS. Temporin B is a natural peptide active against Gram positive bacteria but inactive against Gram negative bacteria, TB_KKG6A is an analogue of temporin B showing activity against both Gram positive and Gram negative bacteria. We found that binding to cells occurs only for the active peptide TB_KKG6A; stoichiometry and affinity constant of this peptide toward Escherichia coli cells were determined. PMID:27450805

  20. Infection by verocytotoxin-producing Escherichia coli.

    PubMed Central

    Karmali, M A

    1989-01-01

    Verocytotoxin (VT)-producing Escherichia coli (VTEC) are a newly recognized group of enteric pathogens which are increasingly being recognized as common causes of diarrhea in some geographic settings. Outbreak studies indicate that most patients with VTEC infection develop mild uncomplicated diarrhea. However, a significant risk of two serious and potentially life-threatening complications, hemorrhagic colitis and the hemolytic uremic syndrome, makes VTEC infection a public health problem of serious concern. The main reservoirs of VTEC appear to be the intestinal tracts of animals, and foods of animal (especially bovine) origin are probably the principal sources for human infection. The term VT refers to a family of subunit exotoxins with high biological activity. Individual VTEC strains elaborate one or both of at least two serologically distinct, bacteriophage-mediated VTs (VT1 and VT2) which are closely related to Shiga toxin and are thus also referred to as Shiga-like toxins. The holotoxins bind to cells, via their B subunits, to a specific receptor which is probably the glycolipid, globotriosyl ceramide (Gb3). Binding is followed by internalization of the A subunit, which, after it is proteolytically nicked and reduced to the A1 fragment, inhibits protein synthesis in mammalian cells by inactivating 60S ribosomal subunits through selective structural modification of 28S ribosomal ribonucleic acid. The mechanism of VTEC diarrhea is still controversial, and the relative roles of locally acting VT and "attaching and effacing adherence" of VTEC to the mucosa have yet to be resolved. There is increasing evidence that hemolytic uremic syndrome and possibly hemorrhagic colitis result from the systemic action of VT on vascular endothelial cells. The role of antitoxic immunity in preventing the systemic complications of VTEC infection is being explored. Antibiotics appear to be contraindicated in the treatment of VTEC infection. The most common VTEC serotype associated

  1. Analysis of the genetic determinants coding for the S-fimbrial adhesin (sfa) in different Escherichia coli strains causing meningitis or urinary tract infections.

    PubMed

    Ott, M; Hacker, J; Schmoll, T; Jarchau, T; Korhonen, T K; Goebel, W

    1986-12-01

    Recently we have described the molecular cloning of the genetic determinant coding for the S-fimbrial adhesin (Sfa), a sialic acid-recognizing pilus frequently found among extraintestinal Escherichia coli isolates. Fimbriae from the resulting Sfa+ E. coli K-12 clone were isolated, and an Sfa-specific antiserum was prepared. Western blots indicate that S fimbriae isolated from different uropathogenic and meningitis-associated E. coli strains, including O83:K1 isolates, were serologically related. The Sfa-specific antibodies did not cross-react with P fimbriae, but did cross-react with F1C fimbriae. Furthermore the sfa+ recombinant DNAs and some cloned sfa-flanking regions were used as probes in Southern experiments. Chromosomal DNAs isolated from O18:K1 and O83:K1 meningitis strains with and without S fimbriae and from uropathogenic O6:K+ strains were hybridized against these sfa-specific probes. Only one copy of the sfa determinant was identified on the chromosome of these strains. No sfa-specific sequences were observed on the chromosome of E. coli K-12 strains and an O7:K1 isolate. With the exception of small alterations in the sfa-coding region the genetic determinants for S fimbriae were identical in uropathogenic O6:K+ and meningitis O18:K1 and O83:K1 strains. The sfa determinant was also detected on the chromosome of K1 isolates with an Sfa-negative phenotype, and specific cross-hybridization signals were visible after blotting against F1C-specific DNA. In addition homology among the different strains was observed in the sfa-flanking regions.

  2. Recurrent Hemolytic and Uremic Syndrome Induced by Escherichia Coli

    PubMed Central

    Commereuc, Morgane; Weill, Francois-Xavier; Loukiadis, Estelle; Gouali, Malika; Gleizal, Audrey; Kormann, Raphaël; Ridel, Christophe; Frémeaux-Bacchi, Véronique; Rondeau, Eric; Hertig, Alexandre

    2016-01-01

    Abstract A widespread belief is that typical hemolytic and uremic syndrome (HUS) does not recur. We report the case of a patient infected twice with raw milk taken from his own cow and containing a Shiga toxin–producing Escherichia coli O174:H21 that induced recurrent HUS causing severe renal and cerebral disorders. A genomic comparison of the human and bovine Shiga toxin–producing Escherichia coli O174:H21 isolates revealed that they were identical. Typical HUS may recur. Since milk from this animal was occasionally distributed locally, thereby posing a serious threat for the whole village, this particular cow was destroyed. PMID:26735524

  3. Recent advances in adherence and invasion of pathogenic Escherichia coli

    PubMed Central

    Kalita, Anjana; Hu, Jia; Torres, Alfredo G.

    2014-01-01

    Purpose of review Colonization of the host epithelia by pathogenic Escherichia coli is influenced by the ability of the bacteria to interact with host surfaces. Because the initial step of an E. coli infection is to adhere, invade, and persist within host cells, some strategies used by intestinal and extra-intestinal E. coli to infect host cell are presented. Recent findings This review highlights recent progress understanding how extra-intestinal pathogenic E. coli strains express specific adhesins/invasins that allow colonization of the urinary tract or the meninges, while intestinal E. coli strains are able to colonize different regions of the intestinal tract using other specialized adhesins/invasins. Finally, evaluation of, different diets and environmental conditions regulating the colonization of these pathogens is discussed. Summary Discovery of new interactions between pathogenic E. coli and the host epithelial cells unravels the need of more mechanistic studies that can provide new clues in how to combat these infections. PMID:25023740

  4. The Core Lipopolysaccharide of Escherichia coli Is a Ligand for the Dendritic-Cell-Specific Intercellular Adhesion Molecule Nonintegrin CD209 Receptor

    PubMed Central

    Klena, John; Zhang, Pei; Schwartz, Olivier; Hull, Sheila; Chen, Tie

    2005-01-01

    The dendritic-cell-specific intercellular adhesion molecule nonintegrin (DC-SIGN) CD209 is a receptor for Escherichia coli K-12 that promotes bacterial adherence and phagocytosis. However, the ligand of E. coli for DC-SIGN has not yet been identified. In this study, we found that DC-SIGN did not mediate the phagocytosis of several pathogenic strains of E. coli, including enteropathogenic E. coli, enterohemorrhagic E. coli, enterotoxigenic E. coli, and uropathogenic E. coli, in dendritic cells or HeLa cells expressing human DC-SIGN antigen. However, we showed that an outer core lipopolysaccharide (LPS) (rough) mutant, unlike an inner core LPS (deep rough) mutant or O-antigen-expressing recombinant of E. coli K-12 was phagocytosed. These results demonstrate that the host cells expressing DC-SIGN can phagocytose E. coli in part by interacting with the complete core region of the LPS molecule. These results provide a mechanism for how O antigen acts as an antiphagocytic factor. PMID:15716442

  5. The Biology of the Escherichia coli Extracellular Matrix.

    PubMed

    Hufnagel, David A; Depas, William H; Chapman, Matthew R

    2015-06-01

    Escherichia coli is one of the world's best-characterized organisms, because it has been extensively studied for over a century. However, most of this work has focused on E. coli grown under laboratory conditions that do not faithfully simulate its natural environments. Therefore, the historical perspectives on E. coli physiology and life cycle are somewhat skewed toward experimental systems that feature E. coli growing logarithmically in a test tube. Typically a commensal bacterium, E. coli resides in the lower intestines of a slew of animals. Outside of the lower intestine, E. coli can adapt and survive in a very different set of environmental conditions. Biofilm formation allows E. coli to survive, and even thrive, in environments that do not support the growth of planktonic populations. E. coli can form biofilms virtually everywhere: in the bladder during a urinary tract infection, on in-dwelling medical devices, and outside of the host on plants and in the soil. The E. coli extracellular matrix (ECM), primarily composed of the protein polymer named curli and the polysaccharide cellulose, promotes adherence to organic and inorganic surfaces and resistance to desiccation, the host immune system, and other antimicrobials. The pathways that govern E. coli biofilm formation, cellulose production, and curli biogenesis will be discussed in this article, which concludes with insights into the future of E. coli biofilm research and potential therapies. PMID:26185090

  6. Rates of mutation and host transmission for an Escherichia coli clone over 3 years.

    PubMed

    Reeves, Peter R; Liu, Bin; Zhou, Zhemin; Li, Dan; Guo, Dan; Ren, Yan; Clabots, Connie; Lan, Ruiting; Johnson, James R; Wang, Lei

    2011-01-01

    Although over 50 complete Escherichia coli/Shigella genome sequences are available, it is only for closely related strains, for example the O55:H7 and O157:H7 clones of E. coli, that we can assign differences to individual evolutionary events along specific lineages. Here we sequence the genomes of 14 isolates of a uropathogenic E. coli clone that persisted for 3 years within a household, including a dog, causing a urinary tract infection (UTI) in the dog after 2 years. The 20 mutations observed fit a single tree that allows us to estimate the mutation rate to be about 1.1 per genome per year, with minimal evidence for adaptive change, including in relation to the UTI episode. The host data also imply at least 6 host transfer events over the 3 years, with 2 lineages present over much of that period. To our knowledge, these are the first direct measurements for a clone in a well-defined host community that includes rates of mutation and host transmission. There is a concentration of non-synonymous mutations associated with 2 transfers to the dog, suggesting some selection pressure from the change of host. However, there are no changes to which we can attribute the UTI event in the dog, which suggests that this occurrence after 2 years of the clone being in the household may have been due to chance, or some unknown change in the host or environment. The ability of a UTI strain to persist for 2 years and also to transfer readily within a household has implications for epidemiology, diagnosis, and clinical intervention.

  7. Virulence and plasmidic resistance determinants of Escherichia coli isolated from municipal and hospital wastewater treatment plants.

    PubMed

    Calhau, Vera; Mendes, Catarina; Pena, Angelina; Mendonça, Nuno; Da Silva, Gabriela Jorge

    2015-06-01

    Escherichia coli is simultaneously an indicator of water contamination and a human pathogen. This study aimed to characterize the virulence and resistance of E. coli from municipal and hospital wastewater treatment plants (WWTPs) in central Portugal. From a total of 193 isolates showing reduced susceptibility to cefotaxime and/or nalidixic acid, 20 E. coli with genetically distinct fingerprint profiles were selected and characterized. Resistance to antimicrobials was determined using the disc diffusion method. Extended spectrum β-lactamase and plasmid-mediated quinolone resistance genes, phylogroups, pathogenicity islands (PAIs) and virulence genes were screened by polymerase chain reaction (PCR). CTX-M producers were typed by multilocus sequence typing. Resistance to beta-lactams was associated with the presence of bla(TEM), bla(SHV), bla(CTX-M-15) and bla(CTX-M-32). Plasmid-mediated quinolone resistance was associated with qnrA, qnrS and aac(6')-Ib-cr. Aminoglycoside resistance and multidrug-resistant phenotypes were also detected. PAI IV(536), PAI II(CFT073), PAI II(536) and PAI I(CFT073), and uropathogenic genes iutA, papAH and sfa/foc were detected. With regard to the clinical ST131 clone, it carried bla(CTX-M-15), blaTEM-type, qnrS and aac(6')-lb-cr; IncF and IncP plasmids, and virulence factors PAI IV(536), PAI I(CFT073), PAI II(CFT073), iutA, sfa/foc and papAH were identified in the effluent of a hospital plant. WWTPs contribute to the dissemination of virulent and resistant bacteria in water ecosystems, constituting an environmental and public health risk.

  8. A Multiepitope Subunit Vaccine Conveys Protection against Extraintestinal Pathogenic Escherichia coli in Mice▿ †

    PubMed Central

    Wieser, Andreas; Romann, Eva; Magistro, Giuseppe; Hoffmann, Christiane; Nörenberg, Dominik; Weinert, Kirsten; Schubert, Sören

    2010-01-01

    Infections due to extraintestinal pathogenic Escherichia coli (ExPEC) are common in humans and animals and include urinary tract infections (from uropathogenic E. coli [UPEC]), septicemia, and wound infections. These infections result in significant morbidity and mortality and in high health care costs. In view of the increasing number of ExPEC infections and the ever-growing antibiotic resistance capability of ExPEC isolates, preventive measures such as an effective vaccine against ExPEC are desirable. An ExPEC vaccine may be cost-effective for select patient groups. Previous vaccine candidates consisted of single target proteins or whole ExPEC cells. Here we describe a subunit vaccine against ExPEC which is based on immunodominant epitopes of the virulence-associated ExPEC proteins FyuA, IroN, ChuA, IreA, Iha, and Usp. Using a novel approach of computer-aided design, two completely artificial genes were created, both encoding eight peptide domains derived from these ExPEC proteins. The recombinant expression of these two genes resulted in a protein vaccine directed against ExPEC but not against commensal E. coli of the gut flora. In mice, the vaccine was highly immunogenic, eliciting both strong humoral and cellular immune responses. Nasal application resulted in high secretory immunoglobulin A (sIgA) production, which was detectable on the mucosal surface of the urogenital tract. Finally, it conveyed protection, as shown by a significant reduction of bacterial load in a mouse model of ExPEC peritonitis. This study provides evidence that a novel vaccine design encompassing distinct epitopes of virulence-associated ExPEC proteins may represent a means for providing a protective and pathogen-specific vaccine. PMID:20498257

  9. Role of the Vpe Carbohydrate Permease in Escherichia coli Urovirulence and Fitness In Vivo

    PubMed Central

    Martinez-Jéhanne, Vanessa; Pichon, Christophe; du Merle, Laurence; Poupel, Olivier; Cayet, Nadège; Bouchier, Christiane

    2012-01-01

    Uropathogenic Escherichia coli (UPEC) strains are a leading cause of infections in humans, but the mechanisms governing host colonization by this bacterium remain poorly understood. Previous studies have identified numerous gene clusters encoding proteins involved in sugar transport, in pathogen-specific islands. We investigated the role in fitness and virulence of the vpe operon encoding an EII complex of the phosphotransferase (PTS) system, which is found more frequently in human strains from infected urine and blood (45%) than in E. coli isolated from healthy humans (15%). We studied the role of this locus in vivo, using the UPEC E. coli strain AL511, mutants, and complemented derivatives in two experimental mouse models of infection. Mutant strains displayed attenuated virulence in a mouse model of sepsis. A role in kidney colonization was also demonstrated by coinfection experiments in a mouse model of pyelonephritis. Electron microscopy examinations showed that the vpeBC mutant produced much smaller amounts of a capsule-like surface material than the wild type, particularly when growing in human urine. Complementation of the vpeBC mutation led to an increase in the amount of exopolysaccharide, resistance to serum killing, and virulence. It was therefore clear that the loss of vpe genes was responsible for all the observed phenotypes. We also demonstrated the involvement of the vpe locus in gut colonization in the streptomycin-treated mouse model of intestinal colonization. These findings confirm that carbohydrate transport and metabolism underlie the ability of UPEC strains to colonize the host intestine and to infect various host sites. PMID:22615242

  10. The Serine Protease Pic From Enteroaggregative Escherichia coli Mediates Immune Evasion by the Direct Cleavage of Complement Proteins.

    PubMed

    Abreu, Afonso G; Fraga, Tatiana R; Granados Martínez, Adriana P; Kondo, Marcia Y; Juliano, Maria A; Juliano, Luiz; Navarro-Garcia, Fernando; Isaac, Lourdes; Barbosa, Angela S; Elias, Waldir P

    2015-07-01

    Enteroaggregative and uropathogenic Escherichia coli, Shigella flexneri 2a, and the hybrid enteroaggregative/Shiga toxin-producing E. coli strain (O104:H4) are important pathogens responsible for intestinal and urinary tract infections, as well as sepsis and hemolytic uremic syndrome. They have in common the production of a serine protease called Pic. Several biological roles for Pic have been described, including protection of E. coli DH5α from complement-mediated killing. Hereby we showed that Pic significantly reduces complement activation by all 3 pathways. Pic cleaves purified C3/C3b and other proteins from the classic and lectin pathways, such as C4 and C2. Cleavage fragments of C3, C4, and C2 were also observed with HB101(pPic1) culture supernatants, and C3 cleavage sites were mapped by fluorescence resonance energy transfer peptides. Experiments using human serum as a source of complement proteins confirmed Pic proteolytic activity on these proteins. Furthermore, Pic works synergistically with the human complement regulators factor I and factor H, promoting inactivation of C3b. In the presence of both regulators, further degradation of C3 α' chain was observed. Therefore, Pic may contribute to immune evasion of E. coli and S. flexneri, favoring invasiveness and increasing the severity of the disorders caused by these pathogens.

  11. Genes and proteins of Escherichia coli K-12.

    PubMed

    Riley, M

    1998-01-01

    GenProtEC is a database of Escherichia coli genes and their gene products, classified by type of function and physiological role and with citations to the literature for each. Also present are data on sequence similarities among E.coli proteins, representing groups of paralogous genes, with PAM values, percent identity of amino acids, length of alignment and percent aligned. GenProtEC can be accessed at the URL http://www.mbl.edu/html/ecoli.html PMID:9399799

  12. Effective assembly of fimbriae in Escherichia coli depends on the translocation assembly module nanomachine.

    PubMed

    Stubenrauch, Christopher; Belousoff, Matthew J; Hay, Iain D; Shen, Hsin-Hui; Lillington, James; Tuck, Kellie L; Peters, Kate M; Phan, Minh-Duy; Lo, Alvin W; Schembri, Mark A; Strugnell, Richard A; Waksman, Gabriel; Lithgow, Trevor

    2016-01-01

    Outer membrane proteins are essential for Gram-negative bacteria to rapidly adapt to changes in their environment. Intricate remodelling of the outer membrane proteome is critical for bacterial pathogens to survive environmental changes, such as entry into host tissues(1-3). Fimbriae (also known as pili) are appendages that extend up to 2 μm beyond the cell surface to function in adhesion for bacterial pathogens, and are critical for virulence. The best-studied examples of fimbriae are the type 1 and P fimbriae of uropathogenic Escherichia coli, the major causative agent of urinary tract infections in humans. Fimbriae share a common mode of biogenesis, orchestrated by a molecular assembly platform called 'the usher' located in the outer membrane. Although the mechanism of pilus biogenesis is well characterized, how the usher itself is assembled at the outer membrane is unclear. Here, we report that a rapid response in usher assembly is crucially dependent on the translocation assembly module. We assayed the assembly reaction for a range of ushers and provide mechanistic insight into the β-barrel assembly pathway that enables the rapid deployment of bacterial fimbriae. PMID:27572967

  13. Cathelicidin Augments Epithelial Receptivity and Pathogenesis in Experimental Escherichia coli Cystitis

    PubMed Central

    Danka, Elizabeth S.; Hunstad, David A.

    2015-01-01

    Background. Cathelicidin is a proposed defender against infection of the urinary tract via its antimicrobial properties, but its activity has not been delineated in a dedicated cystitis model. Methods. Female C57Bl/6 mice, wild type or deficient in cathelin-related antimicrobial peptide (CRAMP; an ortholog of the sole human cathelicidin, LL-37), were infected transurethrally with the cystitis-derived uropathogenic Escherichia coli (UPEC) strain UTI89. Infection course was evaluated by bladder titers, intracellular bacterial community quantification, and histological analysis. Immune responses and resolution were characterized through cytokine profiling, microscopy, and quantitation of epithelial recovery from exfoliation. Results. CRAMP-deficient mice exhibited significantly lower bladder bacterial loads and fewer intracellular bacterial communities during acute cystitis. Although differences in bacterial titers were evident as early as 1 hour after infection, CRAMP-deficient mice showed no baseline alterations in immune activation, uroepithelial structure, apical expression of uroplakins (which serve as bacterial receptors), or intracellular bacterial growth rate. CRAMP-deficient hosts demonstrated less intense cytokine responses, diminished neutrophil infiltration, and accelerated uroepithelial recovery. Conclusions. Mice lacking the antimicrobial peptide cathelicidin experienced less severe infection than wild-type mice in a well-established model of cystitis. Although CRAMP exhibits in vitro antibacterial activity against UPEC, it may enhance UPEC infection in the bladder by promoting epithelial receptivity and local inflammation. PMID:25336727

  14. Interactions between genotype and environment drive the metabolic phenotype within Escherichia coli isolates.

    PubMed

    Sabarly, Victor; Aubron, Cécile; Glodt, Jérémy; Balliau, Thierry; Langella, Olivier; Chevret, Didier; Rigal, Odile; Bourgais, Aurélie; Picard, Bertrand; de Vienne, Dominique; Denamur, Erick; Bouvet, Odile; Dillmann, Christine

    2016-01-01

    To gain insights into the adaptation of the Escherichia coli species to different environments, we monitored protein abundances using quantitative proteomics and measurements of enzymatic activities of central metabolism in a set of five representative strains grown in four contrasted culture media including human urine. Two hundred and thirty seven proteins representative of the genome-scale metabolic network were identified and classified into pathway categories. We found that nutrient resources shape the general orientation of metabolism through coordinated changes in the average abundances of proteins and in enzymatic activities that all belong to the same pathway category. For example, each culture medium induces a specific oxidative response whatever the strain. On the contrary, differences between strains concern isolated proteins and enzymes within pathway categories in single environments. Our study confirms the predominance of genotype by environment interactions at the proteomic and enzyme activity levels. The buffering of genetic variation when considering life-history traits suggests a multiplicity of evolutionary strategies. For instance, the uropathogenic isolate CFT073 shows a deregulation of iron demand and increased oxidative stress response.

  15. Comparison of Asymptomatic Bacteriuria Escherichia coli Isolates from Healthy Individuals versus Those from Hospital Patients Shows that Long-Term Bladder Colonization Selects for Attenuated Virulence Phenotypes

    PubMed Central

    Salvador, Ellaine; Wagenlehner, Florian; Köhler, Christian-Daniel; Mellmann, Alexander; Hacker, Jörg; Svanborg, Catharina

    2012-01-01

    Asymptomatic bacteriuria (ABU) is a condition where bacteria stably colonize the urinary tract, in a manner closely resembling commensalism at other mucosal sites. The patients carry >105 CFU/ml for extended periods of time and rarely develop symptoms. Contrasting the properties of ABU strains to those of uropathogenic isolates causing symptomatic infection is therefore highly relevant to understand mechanisms of bacterial adaptation. The prototype ABU strain Escherichia coli 83972 has a smaller genome than uropathogenic E. coli (UPEC) strains with deletions or point mutations in several virulence genes, suggesting that ABU strains undergo a programmed reductive evolution within human hosts. This study addressed if these observations can be generalized. Strains causing ABU in outpatients or hospitalized patients after catheterization or other invasive procedures were compared to commensal E. coli isolates from the intestinal flora of healthy individuals. Notably, clonal complex 73 (CC73) was a prominent phylogenetic lineage dominated by ABU isolates. ABU isolates from outpatients and hospitalized patients had a similar overall virulence gene repertoire, which distinguished them from many commensals, but typical UPEC virulence genes were less frequently attenuated in hospital strains than in outpatient strains or commensals. The decreased virulence potential of outpatient ABU isolates relative to that of ABU strains from hospitalized patients supports the hypothesis that loss of expression or decay of virulence genes facilitates long-term carriage and adaptation to host environments. PMID:22104113

  16. YeeO from Escherichia coli exports flavins

    PubMed Central

    McAnulty, Michael J; Wood, Thomas K

    2014-01-01

    Multidrug and toxic compound extrusion (MATE) proteins help maintain cellular homeostasis by secreting metabolic wastes. Flavins may occur as cellular waste products, with their production and secretion providing potential benefit for industrial applications related to biofuel cells. Here we find that MATE protein YeeO from Escherichia coli exports both flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). Significant amounts of flavins were trapped intracellularly when YeeO was produced indicating transport limits secretion of flavins. Wild-type E. coli secreted 3 flavins (riboflavin, FMN, and FAD), so E. coli likely produces additional flavin transporters. PMID:25482085

  17. An integrated database to support research on Escherichia coli

    SciTech Connect

    Baehr, A.; Dunham, G.; Matsuda, Hideo; Michaels, G.; Taylor, R.; Overbeek, R.; Rudd, K.E. ); Ginsburg, A.; Joerg, D.; Kazic, T. . Dept. of Genetics); Hagstrom, R.; Zawada, D. ); Smith, C.; Yoshida, Kaoru )

    1992-01-01

    We have used logic programming to design and implement a prototype database of genomic information for the model bacterial organism Escherichia coli. This report presents the fundamental database primitives that can be used to access and manipulate data relating to the E. coli genome. The present system, combined with a tutorial manual, provides immediate access to the integrated knowledge base for E. coli chromosome data. It also serves as the foundation for development of more user-friendly interfaces that have the same retrieval power and high-level tools to analyze complex chromosome organization.

  18. YeeO from Escherichia coli exports flavins.

    PubMed

    McAnulty, Michael J; Wood, Thomas K

    2014-01-01

    Multidrug and toxic compound extrusion (MATE) proteins help maintain cellular homeostasis by secreting metabolic wastes. Flavins may occur as cellular waste products, with their production and secretion providing potential benefit for industrial applications related to biofuel cells. Here we find that MATE protein YeeO from Escherichia coli exports both flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). Significant amounts of flavins were trapped intracellularly when YeeO was produced indicating transport limits secretion of flavins. Wild-type E. coli secreted 3 flavins (riboflavin, FMN, and FAD), so E. coli likely produces additional flavin transporters. PMID:25482085

  19. Enteropathogenic Escherichia coli Serotypes and Endemic Diarrhea in Infants

    PubMed Central

    Toledo, M. Regina F.; Alvariza, M. do Carmo B.; Murahovschi, Jayme; Ramos, Sonia R. T. S.; Trabulsi, Luiz R.

    1983-01-01

    Enteropathogenic Escherichia coli serotypes were searched for in feces of 550 children with endemic diarrhea and in 129 controls, in São Paulo, in 1978 and 1979; serotypes O111ab:H−, O111ab:H2, and O119:H6 were significantly associated with diarrhea in children 0 to 5 months old and were the most frequent agents of diarrhea in this age group as compared with enterotoxigenic and enteroinvasive E. coli, Salmonella sp., Shigella sp., and Yersinia enterocolitica. It is concluded that various enteropathogenic E. coli serotypes may be agents of endemic infantile diarrhea. PMID:6339384

  20. Molecular characterization of diarrheagenic Escherichia coli from Libya.

    PubMed

    Ali, Mostafa Mohamed M; Mohamed, Zienat Kamel; Klena, John D; Ahmed, Salwa Fouad; Moussa, Tarek A A; Ghenghesh, Khalifa Sifaw

    2012-05-01

    Diarrheagenic Escherichia coli (DEC) are important enteric pathogens that cause a wide variety of gastrointestinal diseases, particularly in children. Escherichia coli isolates cultured from 243 diarrheal stool samples obtained from Libyan children and 50 water samples were screened by polymerase chain reaction (PCR) for genes characteristic of enteroaggregative E. coli (EAEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enterohemorrhagic E. coli (EHEC), and enteroinvasive E. coli (EIEC). The DEC were detected in 21 (8.6%) children with diarrhea; 10 (4.1%) cases were identified as EAEC, 3 (1.2%) as EPEC, and 8 (3.3%) were ETEC; EHEC, and EIEC were not detected. All DEC were grouped phylogenetically by PCR with the majority (> 70%) identified as phylogenetic groups A and B1. The EAEC isolates were also tested for eight genes associated with virulence using PCR. Multi-virulence (≥ 3 virulence factors) was found in 50% of EAEC isolates. Isolated EAEC possessed different virulence traits and belonged to different phylogenetic groups indicating their heterogeneity.

  1. Plasmolysis of Escherichia coli B-r with sucrose.

    PubMed

    Scheie, P O

    1969-05-01

    Escherichia coli B/r cells were plasmolyzed in sucrose solutions and observed under phase contrast. The prevalence of plasmolysis under various conditions was noted, and the degree of plasmolysis was categorized as slight, extensive, or severe. The presence of ions reduced the prevalence of plasmolysis. Survival curves showed that extensive plasmolysis was not lethal to colony-forming ability.

  2. TRIMETHOPRIM-SULFAMETHOXAZOLE RESISTANCE IN SEWAGE ISOLATES OF ESCHERICHIA COLI

    EPA Science Inventory

    The increase in resistance rates to trimehtoprim-sulfamethoxazole (TMP/SMX) in isolates of Escherichia coli has become a matter of increasing concern. This has been particularly true in reference to community acquired urinary tract infections (UTI). This study utilized sewage i...

  3. Enteroinvasive Escherichia coli severe dysentery complicated by rotavirus gastroenteritis.

    PubMed

    Pacheco-Gil, Leova; Ochoa, Theresa J; Flores-Romo, Leopoldo; DuPont, Herbert L; Estrada-Garcia, Teresa

    2006-11-01

    Enteroinvasive Escherichia coli (EIEC) is an important agent of pediatric diarrhea and dysentery in developing countries. We report a life-threatening severe dysentery case due to EIEC in a malnourished 4-month-old male, native Indian infant co-infected with rotavirus. The severe gastrointestinal bleeding anemia and hypovolemic shock was successfully treated with IV blood transfusions, rehydration and antibiotic therapy.

  4. Genotypic Characterization of Enterotoxigenic Escherichia coli Strains Causing Traveler's Diarrhea

    PubMed Central

    Rivera, Fulton P.; Medina, Anicia M.; Aldasoro, Edelweiss; Sangil, Anna; Gascon, Joaquim; Ochoa, Theresa J.; Vila, Jordi

    2013-01-01

    This study aims to characterize the presence of virulence factors of enterotoxigenic Escherichia coli (ETEC) causing traveler's diarrhea. Among 52 ETEC isolates, the most common toxin type was STh, and the most frequent colonization factors (CFs) were CS21, CS6, and CS3. On the other hand, the nonclassical virulence factors EAST1 and EatA were frequently present. PMID:23224092

  5. armA and aminoglycoside resistance in Escherichia coli.

    PubMed

    González-Zorn, Bruno; Teshager, Tirushet; Casas, María; Porrero, María C; Moreno, Miguel A; Courvalin, Patrice; Domínguez, Lucas

    2005-06-01

    We report armA in an Escherichia coli pig isolate from Spain. The resistance gene was borne by self-transferable IncN plasmid pMUR050. Molecular analysis of the plasmid and of the armA locus confirmed the spread of this resistance determinant.

  6. armA and Aminoglycoside Resistance in Escherichia coli

    PubMed Central

    González-Zorn, Bruno; Teshager, Tirushet; Casas, María; Porrero, María C.; Courvalin, Patrice; Domínguez, Lucas

    2005-01-01

    We report armA in an Escherichia coli pig isolate from Spain. The resistance gene was borne by self-transferable IncN plasmid pMUR050. Molecular analysis of the plasmid and of the armA locus confirmed the spread of this resistance determinant. PMID:15963296

  7. Escherichia coli and other Enterobacteriaceae: Food poisoning and health effects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The family Enterobactericeae consists of rod-shaped, Gram-negative, facultatively anaerobic, non-spore forming bacteria and also includes the food-borne pathogens, Cronobacter spp., Escherichia coli, Salmonella enterica, Shigella spp., and Yersinia spp. Illness caused by these pathogens is acquired...

  8. Multidrug-Resistant Escherichia coli in Bovine Animals, Europe

    PubMed Central

    Brennan, Evan; Martins, Marta; McCusker, Matthew P.; Wang, Juan; Alves, Bruno Martins; Hurley, Daniel; El Garch, Farid; Woehrlé, Frédérique; Miossec, Christine; McGrath, Leisha; Srikumar, Shabarinath; Wall, Patrick

    2016-01-01

    Of 150 Escherichia coli strains we cultured from specimens taken from cattle in Europe, 3 had elevated MICs against colistin. We assessed all 3 strains for the presence of the plasmid-mediated mcr-1 gene and identified 1 isolate as mcr-1–positive and co-resistant to β-lactam, florfenicol, and fluoroquinolone antimicrobial compounds. PMID:27533105

  9. 21 CFR 866.3255 - Escherichia coli serological reagents.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Escherichia coli serological reagents. 866.3255 Section 866.3255 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3255...

  10. 21 CFR 866.3255 - Escherichia coli serological reagents.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Escherichia coli serological reagents. 866.3255 Section 866.3255 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3255...

  11. 21 CFR 866.3255 - Escherichia coli serological reagents.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Escherichia coli serological reagents. 866.3255 Section 866.3255 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3255...

  12. 21 CFR 866.3255 - Escherichia coli serological reagents.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Escherichia coli serological reagents. 866.3255 Section 866.3255 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3255...

  13. 21 CFR 866.3255 - Escherichia coli serological reagents.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Escherichia coli serological reagents. 866.3255 Section 866.3255 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3255...

  14. Multidrug-Resistant Escherichia coli in Bovine Animals, Europe.

    PubMed

    Brennan, Evan; Martins, Marta; McCusker, Matthew P; Wang, Juan; Alves, Bruno Martins; Hurley, Daniel; El Garch, Farid; Woehrlé, Frédérique; Miossec, Christine; McGrath, Leisha; Srikumar, Shabarinath; Wall, Patrick; Fanning, Séamus

    2016-09-01

    Of 150 Escherichia coli strains we cultured from specimens taken from cattle in Europe, 3 had elevated MICs against colistin. We assessed all 3 strains for the presence of the plasmid-mediated mcr-1 gene and identified 1 isolate as mcr-1-positive and co-resistant to β-lactam, florfenicol, and fluoroquinolone antimicrobial compounds. PMID:27533105

  15. Inactivation of Escherichia coli by titanium dioxide photocatalytic oxidation.

    EPA Science Inventory

    Titanium dioxide in the anatase crystalline form was used as a photocatalyst to generate hydroxyl radicals in a flowthrough water reactor. Experiments were performed on pure cultures of Escherichia coli in dechlorinated tap water and a surface water sample to evaluate the disinfe...

  16. Cell surface growth in Escherichia coli: distribution of matrix protein.

    PubMed Central

    Begg, K J

    1978-01-01

    Autoradiography of cell envelope "ghosts" from Escherichia coli was used to demonstrate that newly synthesized molecules of "matrix" protein are inserted at random locations over the entire surface of the outer membrane and that, once inserted, these molecules are not thereafter conserved in any fixed spatial location. Images PMID:355219

  17. Genome Sequence of Enterotoxigenic Escherichia coli Strain B2C.

    PubMed

    Madhavan, T P Vipin; Steen, Jason A; Hugenholtz, Philip; Sakellaris, Harry

    2014-04-10

    Enterotoxigenic Escherichia coli (ETEC) is a major cause of diarrheal disease around the globe, causing an estimated 380,000 deaths annually. The disease is caused by a wide variety of strains. Here, we report the genome sequence of ETEC strain B2C, which was isolated from an American soldier in Vietnam.

  18. Escherichia coli as other Enterobacteriaceae: food poisoning and health effects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many Escherichia coli strains are harmless, and they are an important commensal in the intestinal microflora; however, pathogenic strains also exist. The pathogenic strains can be divided into diarrhea-inducing strains and strains that reside in the intestines but only cause disease in bodily sites...

  19. Escherichia coli Minicell Membranes Are Enriched in Cardiolipin

    PubMed Central

    Koppelman, Cecile-Marie; Den Blaauwen, Tanneke; Duursma, Marc C.; Heeren, Ron M. A.; Nanninga, Nanne

    2001-01-01

    The phospholipid composition of Escherichia coli minicells has been studied as a model for the cell division site. Minicells appeared to be enriched in cardiolipin at the expense of phosphatidylglycerol. Mass spectrometry showed no differences between the gross acyl chain compositions of minicells and wild-type cells. PMID:11567016

  20. Phylogenetic Group Determination of Escherichia coli Isolated from Animals Samples.

    PubMed

    Coura, Fernanda Morcatti; Diniz, Soraia de Araújo; Silva, Marcos Xavier; Mussi, Jamili Maria Suhet; Barbosa, Silvia Minharro; Lage, Andrey Pereira; Heinemann, Marcos Bryan

    2015-01-01

    This study analyzes the occurrence and distribution of phylogenetic groups of 391 strains of Escherichia coli isolated from poultry, cattle, and water buffalo. The frequency of the phylogroups was A = 19%, B1 = 57%, B2 = 2.3%, C = 4.6%, D = 2.8%, E = 11%, and F = 3.3%. Phylogroups A (P < 0.001) and F (P = 0.018) were associated with E. coli strains isolated from poultry, phylogroups B1 (P < 0.001) and E (P = 0.002) were associated with E. coli isolated from cattle, and phylogroups B2 (P = 0.003) and D (P = 0.017) were associated with E. coli isolated from water buffalo. This report demonstrated that some phylogroups are associated with the host analyzed and the results provide knowledge of the phylogenetic composition of E. coli from domestic animals. PMID:26421310

  1. Phylogenetic Group Determination of Escherichia coli Isolated from Animals Samples

    PubMed Central

    Morcatti Coura, Fernanda; Diniz, Soraia de Araújo; Silva, Marcos Xavier; Mussi, Jamili Maria Suhet; Barbosa, Silvia Minharro; Lage, Andrey Pereira; Heinemann, Marcos Bryan

    2015-01-01

    This study analyzes the occurrence and distribution of phylogenetic groups of 391 strains of Escherichia coli isolated from poultry, cattle, and water buffalo. The frequency of the phylogroups was A = 19%, B1 = 57%, B2 = 2.3%, C = 4.6%, D = 2.8%, E = 11%, and F = 3.3%. Phylogroups A (P < 0.001) and F (P = 0.018) were associated with E. coli strains isolated from poultry, phylogroups B1 (P < 0.001) and E (P = 0.002) were associated with E. coli isolated from cattle, and phylogroups B2 (P = 0.003) and D (P = 0.017) were associated with E. coli isolated from water buffalo. This report demonstrated that some phylogroups are associated with the host analyzed and the results provide knowledge of the phylogenetic composition of E. coli from domestic animals. PMID:26421310

  2. EcoCyc: Encyclopedia of Escherichia coli genes and metabolism.

    PubMed

    Karp, P D; Riley, M; Paley, S M; Pellegrini-Toole, A; Krummenacker, M

    1998-01-01

    The encyclopedia of Escherichia coli genes and metabolism (EcoCyc) is a database that combines information about the genome and the intermediary metabolism of E.coli. The database describes 3030 genes of E.coli , 695 enzymes encoded by a subset of these genes, 595 metabolic reactions that occur in E.coli, and the organization of these reactions into 123 metabolic pathways. The EcoCyc graphical user interface allows scientists to query and explore the EcoCyc database using visualization tools such as genomic-map browsers and automatic layouts of metabolic pathways. EcoCyc can be thought of as an electronic review article because of its copious references to the primary literature, and as a (qualitative) computational model of E.coli metabolism. EcoCyc is available at URL http://ecocyc.PangeaSystems.com/ecocyc/

  3. Phylogenetic Group Determination of Escherichia coli Isolated from Animals Samples.

    PubMed

    Coura, Fernanda Morcatti; Diniz, Soraia de Araújo; Silva, Marcos Xavier; Mussi, Jamili Maria Suhet; Barbosa, Silvia Minharro; Lage, Andrey Pereira; Heinemann, Marcos Bryan

    2015-01-01

    This study analyzes the occurrence and distribution of phylogenetic groups of 391 strains of Escherichia coli isolated from poultry, cattle, and water buffalo. The frequency of the phylogroups was A = 19%, B1 = 57%, B2 = 2.3%, C = 4.6%, D = 2.8%, E = 11%, and F = 3.3%. Phylogroups A (P < 0.001) and F (P = 0.018) were associated with E. coli strains isolated from poultry, phylogroups B1 (P < 0.001) and E (P = 0.002) were associated with E. coli isolated from cattle, and phylogroups B2 (P = 0.003) and D (P = 0.017) were associated with E. coli isolated from water buffalo. This report demonstrated that some phylogroups are associated with the host analyzed and the results provide knowledge of the phylogenetic composition of E. coli from domestic animals.

  4. Using zebra mussels to monitor Escherichia coli in environmental waters.

    PubMed

    Selegean, J P; Kusserow, R; Patel, R; Heidtke, T M; Ram, J L

    2001-01-01

    Use of the zebra mussel (Dreissena polymorpha) as an indicator of previously elevated bacteria concentrations in a watershed was examined. The ability of the zebra mussel to accumulate and purge Escherichia coli over several days was investigated in both laboratory and field experiments. In laboratory experiments, periodic enumeration of E. coli in mussels that had been exposed to a dilute solution of raw sewage demonstrated that (i) maximum concentrations of E. coli are reached within a few hours of exposure to sewage, (ii) the tissue concentration attained is higher than the concentration in the ambient water, and (iii) the E. coli concentrations take several days to return to preexposure concentrations when mussels are subsequently placed in sterile water. In field experiments conducted in southeast Michigan in the Clinton River watershed, brief increases in E. coli concentrations in the water were accompanied by increases in mussel concentrations of E. coli that lasted 2 or 3 d. The ability of mussels to retain and to concentrate E. coli made it possible to detect E. coli in the environment under conditions that conventional monitoring may often miss. Sampling caged mussels in a river and its tributaries may enable watershed managers to reduce the sampling frequency normally required to identify critical E. coli sources, thereby providing a more cost-effective river monitoring strategy for bacterial contamination.

  5. Lytic bacteriophages reduce Escherichia coli O157

    PubMed Central

    Ferguson, Sean; Roberts, Cheryl; Handy, Eric; Sharma, Manan

    2013-01-01

    The role of lytic bacteriophages in preventing cross contamination of produce has not been evaluated. A cocktail of three lytic phages specific for E. coli O157:H7 (EcoShield™) or a control (phosphate buffered saline, PBS) was applied to lettuce by either; (1) immersion of lettuce in 500 ml of EcoShield™ 8.3 log PFU/ml or 9.8 log PFU/ml for up to 2 min before inoculation with E. coli O157:H7; (2) spray-application of EcoShield™ (9.3 log PFU/ml) to lettuce after inoculation with E. coli O157:H7 (4.10 CFU/cm2) following exposure to 50 μg/ml chlorine for 30 sec. After immersion studies, lettuce was spot-inoculated with E. coli O157:H7 (2.38 CFU/cm2). Phage-treated, inoculated lettuce pieces were stored at 4°C for and analyzed for E. coli O157:H7 populations for up to 7 d. Immersion of lettuce in 9.8 log PFU/ml EcoShield™ for 2 min significantly (p < 0.05) reduced E. coli O157:H7 populations after 24 h when stored at 4°C compared with controls. Immersion of lettuce in suspensions containing high concentrations of EcoShield™ (9.8 log PFU/ml) resulted in the deposition of high concentrations (7.8 log log PFU/cm2) of bacteriophages on the surface of fresh cut lettuce, potentially contributing to the efficacy of the lytic phages on lettuce. Spraying phages on to inoculated fresh cut lettuce after being washed in hypochlorite solution was significantly more effective in reducing E. coli O157:H7 populations (2.22 log CFU/cm2) on day 0 compared with control treatments (4.10 log CFU/cm2). Both immersion and spray treatments provided protection from E. coli O157:H7 contamination on lettuce, but spray application of lytic bacteriophages to lettuce was more effective in immediately reducing E. coli O157:H7 populations fresh cut lettuce. PMID:23819106

  6. Inhibition of quorum sensing mediated biofilm development and virulence in uropathogens by Hyptis suaveolens.

    PubMed

    Salini, Ramesh; Sindhulakshmi, Muthukrishnan; Poongothai, Thirumaran; Pandian, Shunmugiah Karutha

    2015-04-01

    Bacterial urinary tract infections (UTIs) are the most common nosocomial infections, accounting for about 40 % of all hospital-acquired infections. The bacterial spectrum of nosocomial UTIs is broad and the treatment of UTIs is becoming difficult owing to the emergence of drug resistance. Therefore, it is reasonable to investigate novel and alternative therapeutic strategies to treat UTIs. Since UTIs are caused by uropathogens with quorum sensing (QS)-dependent biofilm forming abilities, interruption of QS systems may be a novel approach to combat drug resistance. In the present study, a methanol extract (and hexane extract derived from it) of the medicinal plant Hyptis suaveolens (L.) were shown to have anti-QS activity against the biosensor strain Chromobacterium violaceum (ATCC 12472). Furthermore, the hexane extract of H. suaveolens (HEHS) inhibited biofilm formation by uropathogens such as Escherichia coli, Proteus vulgaris, Proteus mirabilis, Klebsiella pneumoniae and Serratia marcescens. HEHS promotes the loosening of biofilm architecture and strongly inhibits in vitro biofilm formation by uropathogens, which was more apparent from microscopic images. In addition to this, HEHS reduces the production of QS-dependent virulence factors like protease and hemolysin, along with motility. The partial purification and GC-MS analysis of the active fraction revealed the presence of several therapeutically important compounds which may synergistically act on the uropathogens and possibly reduce the QS-dependent phenotypes. These findings suggest HEHS as potential phytotherapeutic agent which can be employed to formulate protective strategies against biofilm linked infections caused by uropathogens.

  7. An Escherichia coli Mutant That Makes Exceptionally Long Cells

    PubMed Central

    Newman, Elaine B.

    2015-01-01

    ABSTRACT Although Escherichia coli is a very small (1- to 2-μm) rod-shaped cell, here we describe an E. coli mutant that forms enormously long cells in rich media such as Luria broth, as long indeed as 750 μm. These extremely elongated (eel) cells are as long as the longest bacteria known and have no internal subdivisions. They are metabolically competent, elongate rapidly, synthesize DNA, and distribute cell contents along this length. They lack only the ability to divide. The concentration of the essential cell division protein FtsZ is reduced in these eel cells, and increasing this concentration restores division. IMPORTANCE Escherichia coli is usually a very small bacterium, 1 to 2 μm long. We have isolated a mutant that forms enormously long cells, 700 times longer than the usual E. coli cell. E. coli filaments that form under other conditions usually die within a few hours, whereas our mutant is fully viable even when it reaches such lengths. This mutant provides a useful tool for the study of aspects of E. coli physiology that are difficult to investigate with small cells. PMID:25691528

  8. Pentacyclic triterpenes combined with ciprofloxacin help to eradicate the biofilm formed in vitro by Escherichia coli

    PubMed Central

    Wojnicz, Dorota; Tichaczek-Goska, Dorota; Kicia, Marta

    2015-01-01

    Background & objectives: Ciprofloxacin is commonly used in clinical practice for the treatment of recurrent urinary tract infections caused by Escherichia coli. However, very often these recurrent infections are due to a failure in a complete eradication of the microorganisms colonizing the urinary tract, especially in catheterized patients. To enhance the bactericidal activity of ciprofloxacin against biofilm-forming uropathogenic E. coli (UPECs), we examined its effect in combination with two pentacyclic triterpenes – asiatic and ursolic acids. Methods: The anti-biofilm activity of ciprofloxacin and pentacyclic triterpenes - asiatic acid (AA) and ursolic acid (UA), as well as their synergistic effect were tested on two types of surfaces - polystyrene microtiter plates and silicone catheters. It was investigated using the time-killing and biofilm assays. Results: Anti-biofilm activity of ciprofloxacin was not observed on microtiter plates or on the catheters. Ciprofloxacin combined with ursolic acid inhibited the biofilm formation on microtitre plates. This mixture, however, did not express such a strong activity against the synthesis of biofilm on the surface of catheters. Ciprofloxacin combined with asiatic acid had very weak inhibiting effect on the synthesis of biofilm mass on microtitre plates as well as on the catheters. Despite this, both mixtures – ciprofloxacin and asiatic acid, as well as ciprofloxacin and ursolic acid, exhibited strong and significant impact on the eradication of mature biofilm (P < 0.05). Interpretation & conclusions: Although ciprofloxacin is recommended in the treatment of urinary tract infections caused by UPECs, but its efficacy is arguable. Subinhibitory concentrations of ciprofloxacin did not inhibit the formation of biofilm. Pentacyclic triterpenes used in combination with ciprofloxacin enhanced its anti-biofilm effectiveness. However, this anti-biofilm activity was found to depend on the type of surface on which biofilm was

  9. Novel genetic markers define a subgroup of pathogenic Escherichia coli strains belonging to the B2 phylogenetic group.

    PubMed

    Deshpande, Nandan P; Wilkins, Marc R; Mitchell, Hazel M; Kaakoush, Nadeem O

    2015-11-01

    The B2 phylogenetic group of Escherichia coli contains important pathogens such as extraintestinal pathogenic, adherent-invasive, and uropathogenic strains. In this study, we used comparative genomics and statistical methods to identify genetic variations that define a subset of pathogenic strains belonging to the B2 phylogenetic group. An initial proof of concept analysis indicated that five of the 62 E. coli strains available in the Kyoto Encyclopedia of Genes and Genomes database showed close association with B2 adherent-invasive E. coli, forming a subgroup within the B2 phylogenetic group. The tool, kSNP which uses a k-mer approach, and the statistical phenotype prediction tool PPFS2 were then employed to identify 29 high-resolution SNPs, which reaffirmed this grouping. PPFS2 analysis also provided indications that the clustering of this subgroup was highly consistent, and thus, could have a strong phenotypic basis rather than being only evolutionary. Protein homology analyses identified three proteins to be conserved across this subgrouping, two CRISPR-Cas proteins and a hypothetical protein. Functional analyses of these genetic and protein variations may provide insights into the phenotype of these strains.

  10. Cell-Based High-Throughput Screening Identifies Rifapentine as an Inhibitor of Amyloid and Biofilm Formation in Escherichia coli.

    PubMed

    Maher, Marie C; Lim, Ji Youn; Gunawan, Cheston; Cegelski, Lynette

    2015-10-01

    Escherichia coli assemble functional amyloid fibers termed curli that contribute to bacterial adhesion, biofilm formation, and host pathogenesis. We developed a cell-based high-throughput screen to identify inhibitors of curli-mediated adhesion in the laboratory strain MC4100 and curli-associated biofilm formation in the uropathogenic E. coli clinical isolate UTI89. Inhibitors of biofilm formation can operate through many mechanisms, and such inhibitors could hold therapeutic value in preventing and treating urinary tract infections. The curli-specific screen allows the identification of compounds that inhibit either curli expression, curli biogenesis, or adhesion by normally produced curli. In screening the NIH Clinical Collection of 446 compounds, we identified rifapentine as a potent inhibitor in both of these screens. Rifapentine is an antibiotic used to treat tuberculosis that targets RNA polymerase, but prevents curli-dependent adhesion and biofilm formation in E. coli at concentrations below those that affect viability. Rifapentine inhibits curli production and prevents biofilm formation on plastic, on agar, and at the air-liquid interface by inhibiting curli gene transcription. Comparisons with a cephalosporin antibiotic further revealed that curli production is not affected by standard antibiotic treatment and cell killing pressure. Thus, we reveal a new role independent of killing activity for rifapentine as an inhibitor of curli and curli-mediated biofilm formation. PMID:27623312

  11. Genomic Comparative Study of Bovine Mastitis Escherichia coli.

    PubMed

    Kempf, Florent; Slugocki, Cindy; Blum, Shlomo E; Leitner, Gabriel; Germon, Pierre

    2016-01-01

    Escherichia coli, one of the main causative agents of bovine mastitis, is responsible for significant losses on dairy farms. In order to better understand the pathogenicity of E. coli mastitis, an accurate characterization of E. coli strains isolated from mastitis cases is required. By using phylogenetic analyses and whole genome comparison of 5 currently available mastitis E. coli genome sequences, we searched for genotypic traits specific for mastitis isolates. Our data confirm that there is a bias in the distribution of mastitis isolates in the different phylogenetic groups of the E. coli species, with the majority of strains belonging to phylogenetic groups A and B1. An interesting feature is that clustering of strains based on their accessory genome is very similar to that obtained using the core genome. This finding illustrates the fact that phenotypic properties of strains from different phylogroups are likely to be different. As a consequence, it is possible that different strategies could be used by mastitis isolates of different phylogroups to trigger mastitis. Our results indicate that mastitis E. coli isolates analyzed in this study carry very few of the virulence genes described in other pathogenic E. coli strains. A more detailed analysis of the presence/absence of genes involved in LPS synthesis, iron acquisition and type 6 secretion systems did not uncover specific properties of mastitis isolates. Altogether, these results indicate that mastitis E. coli isolates are rather characterized by a lack of bona fide currently described virulence genes.

  12. Genomic Comparative Study of Bovine Mastitis Escherichia coli

    PubMed Central

    Kempf, Florent; Slugocki, Cindy; Blum, Shlomo E.; Leitner, Gabriel; Germon, Pierre

    2016-01-01

    Escherichia coli, one of the main causative agents of bovine mastitis, is responsible for significant losses on dairy farms. In order to better understand the pathogenicity of E. coli mastitis, an accurate characterization of E. coli strains isolated from mastitis cases is required. By using phylogenetic analyses and whole genome comparison of 5 currently available mastitis E. coli genome sequences, we searched for genotypic traits specific for mastitis isolates. Our data confirm that there is a bias in the distribution of mastitis isolates in the different phylogenetic groups of the E. coli species, with the majority of strains belonging to phylogenetic groups A and B1. An interesting feature is that clustering of strains based on their accessory genome is very similar to that obtained using the core genome. This finding illustrates the fact that phenotypic properties of strains from different phylogroups are likely to be different. As a consequence, it is possible that different strategies could be used by mastitis isolates of different phylogroups to trigger mastitis. Our results indicate that mastitis E. coli isolates analyzed in this study carry very few of the virulence genes described in other pathogenic E. coli strains. A more detailed analysis of the presence/absence of genes involved in LPS synthesis, iron acquisition and type 6 secretion systems did not uncover specific properties of mastitis isolates. Altogether, these results indicate that mastitis E. coli isolates are rather characterized by a lack of bona fide currently described virulence genes. PMID:26809117

  13. [Acute diarrheal disease caused by enteropathogenic Escherichia coli in Colombia].

    PubMed

    Gómez-Duarte, Oscar G

    2014-10-01

    Intestinal Escherichia coli pathogens are leading causes of acute diarrheal disease in children less than 5 years in Latin America, Africa and Asia and a leading cause of death in children living in poorest communities in Africa and South East Asia. Studies on the role of E. coli pathogens in childhood diarrhea in Colombia and other countries in Latin America are limited due to the lack of detection assays in clinical laboratories at the main urban medical centers. Recent studies report that enterotoxigenic E. coli is the most common E. coli pathogens associated with diarrhea in children less than 5 years of age. Other E. coli pathotypes have been detected in children with diarrhea including enteropathogenic, enteroaggregative, shiga-toxin producing and diffusely adherent E. coli. It was also found that meat and vegetables at retail stores are contaminated with Shiga-toxin producing E. coli and enteroaggregative E. coli, suggesting that food products are involved in transmission and infection of the susceptible host. More studies are necessary to evaluate the mechanisms of transmission, the impact on the epidemiology of diarrheal disease, and management strategies and prevention of these pathogens affecting the pediatric population in Colombia.

  14. Purification of penicillin-binding protein 2 of Escherichia coli.

    PubMed Central

    Curtis, S J; Strominger, J L

    1981-01-01

    Penicillin-binding protein 2 (PBP-2) of Escherichia coli K-12 was purified by covalent affinity chromatography using 6-aminopenicillanic acid covalently coupled to carboxymethyl-Sepharose (6-APA-CM-Sepharose). Purification of PBP-2 was accomplished by prebinding the methoxy cephalosporin, cefoxitin, to the Triton X-100-solubilized PBPs of E. coli and then incubating the PBPs with 6-APA-CM-Sepharose. Cefoxitin readily binds to all the E. coli PBPs except PBP-2 and, thus, in the presence of cefoxitin, only PBP-2 could bind to the 6-APA-CM-Sepharose. The purification of a mixture of all of the PBPs of E. coli by affinity chromatography is also described. Images PMID:7007320

  15. EcoCyc: Enyclopedia of Escherichia coli Genes and Metabolism.

    PubMed Central

    Karp, P D; Riley, M; Paley, S M; Pellegrini-Toole, A; Krummenacker, M

    1997-01-01

    The Encyclopedia of Genes and Metabolism (EcoCyc) is a database that combines information about the genome and the intermediary metabolism of Escherichia coli. It describes 2970 genes of E.coli, 547 enzymes encoded by these genes, 702 metabolic reactions that occur in E.coli and the organization of these reactions into 107 metabolic pathways. The EcoCyc graphical user interface allows scientists to query and explore the EcoCyc database using visualization tools such as genomic-map browsers and automatic layouts of metabolic pathways. EcoCyc spans the space from sequence to function to allow scientists to investigate an unusually broad range of questions. EcoCyc can be thought of as both an electronic review article because of its copious references to the primary literature, and as an in silicio model of E.coli metabolism that can be probed and analyzed through computational means. PMID:9016502

  16. EcoCyc: Enyclopedia of Escherichia coli Genes and Metabolism.

    PubMed

    Karp, P D; Riley, M; Paley, S M; Pellegrini-Toole, A; Krummenacker, M

    1997-01-01

    The Encyclopedia of Genes and Metabolism (EcoCyc) is a database that combines information about the genome and the intermediary metabolism of Escherichia coli. It describes 2970 genes of E.coli, 547 enzymes encoded by these genes, 702 metabolic reactions that occur in E.coli and the organization of these reactions into 107 metabolic pathways. The EcoCyc graphical user interface allows scientists to query and explore the EcoCyc database using visualization tools such as genomic-map browsers and automatic layouts of metabolic pathways. EcoCyc spans the space from sequence to function to allow scientists to investigate an unusually broad range of questions. EcoCyc can be thought of as both an electronic review article because of its copious references to the primary literature, and as an in silicio model of E.coli metabolism that can be probed and analyzed through computational means.

  17. The different ecological niches of enterotoxigenic Escherichia coli.

    PubMed

    Gonzales-Siles, Lucia; Sjöling, Åsa

    2016-03-01

    Enterotoxigenic Escherichia coli (ETEC) is a water and food-borne pathogen that infects the small intestine of the human gut and causes diarrhoea. Enterotoxigenic E. coli adheres to the epithelium by means of colonization factors and secretes two enterotoxins, the heat labile toxin and/or the heat stable toxin that both deregulate ion channels and cause secretory diarrhoea. Enterotoxigenic E. coli as all E. coli, is a versatile organism able to survive and grow in different environments. During transmission and infection, ETEC is exposed to various environmental cues that have an impact on survivability and virulence. The ability to cope with exposure to different stressful habitats is probably shaping the pool of virulent ETEC strains that cause both endemic and epidemic infections. This review will focus on the ecology of ETEC in its different habitats and interactions with other organisms as well as abiotic factors. PMID:26522129

  18. Eco Cyc: encyclopedia of Escherichia coli genes and metabolism.

    PubMed

    Karp, P D; Riley, M; Paley, S M; Pellegrini-Toole, A; Krummenacker, M

    1999-01-01

    The EcoCyc database describes the genome and gene products of Escherichia coli, its metabolic and signal-transduction pathways, and its tRNAs. The database describes 4391 genes of E.coli, 695 enzymes encoded by a subset of these genes, 904 metabolic reactions that occur in E.coli, and the organization of these reactions into 129 metabolic pathways. The EcoCyc graphical user interface allows scientists to query and explore the EcoCyc database using visualization tools such as genomic-map browsers and automatic layouts of metabolic pathways. EcoCyc has many references to the primary literature, and is a (qualitative) computational model of E. coli metabolism. EcoCyc is available at URL http://ecocyc. PangeaSystems.com/ecocyc/

  19. The different ecological niches of enterotoxigenic Escherichia coli.

    PubMed

    Gonzales-Siles, Lucia; Sjöling, Åsa

    2016-03-01

    Enterotoxigenic Escherichia coli (ETEC) is a water and food-borne pathogen that infects the small intestine of the human gut and causes diarrhoea. Enterotoxigenic E. coli adheres to the epithelium by means of colonization factors and secretes two enterotoxins, the heat labile toxin and/or the heat stable toxin that both deregulate ion channels and cause secretory diarrhoea. Enterotoxigenic E. coli as all E. coli, is a versatile organism able to survive and grow in different environments. During transmission and infection, ETEC is exposed to various environmental cues that have an impact on survivability and virulence. The ability to cope with exposure to different stressful habitats is probably shaping the pool of virulent ETEC strains that cause both endemic and epidemic infections. This review will focus on the ecology of ETEC in its different habitats and interactions with other organisms as well as abiotic factors.

  20. Compilation of DNA sequences of Escherichia coli

    PubMed Central

    Kröger, Manfred

    1989-01-01

    We have compiled the DNA sequence data for E.coli K12 available from the GENBANK and EMBO databases and over a period of several years independently from the literature. We have introduced all available genetic map data and have arranged the sequences accordingly. As far as possible the overlaps are deleted and a total of 940,449 individual bp is found to be determined till the beginning of 1989. This corresponds to a total of 19.92% of the entire E.coli chromosome consisting of about 4,720 kbp. This number may actually be higher by some extra 2% derived from the sequence of lysogenic bacteriophage lambda and the various insertion sequences. This compilation may be available in machine readable form from one of the international databanks in some future. PMID:2654890

  1. Escherichia coli as a model active colloid: A practical introduction.

    PubMed

    Schwarz-Linek, Jana; Arlt, Jochen; Jepson, Alys; Dawson, Angela; Vissers, Teun; Miroli, Dario; Pilizota, Teuta; Martinez, Vincent A; Poon, Wilson C K

    2016-01-01

    The flagellated bacterium Escherichia coli is increasingly used experimentally as a self-propelled swimmer. To obtain meaningful, quantitative results that are comparable between different laboratories, reproducible protocols are needed to control, 'tune' and monitor the swimming behaviour of these motile cells. We critically review the knowledge needed to do so, explain methods for characterising the colloidal and motile properties of E. coli cells, and propose a protocol for keeping them swimming at constant speed at finite bulk concentrations. In the process of establishing this protocol, we use motility as a high-throughput probe of aspects of cellular physiology via the coupling between swimming speed and the proton motive force. PMID:26310235

  2. Cloning of a Thiobacillus ferrooxidans plasmid in Escherichia coli

    SciTech Connect

    Holmes, D.S.; Lobos, J.H.; Bopp, L.H.; Welch, G.C.

    1984-01-01

    Three separate plasmids of 6, 7, 16, and >23 kilobases were purified from a single clone of Thiobacillus ferrooxidans ATCC 33020 grown in the presence of uranium. The 6.7-kilobase plasmid (pTfl) was cloned separately into the HindIII or BamHI site of Escherichia coli plasmid pBR322. Restriction maps of the recombinant plasmids, termed pTf100 and pTf110, respectively, were constructed, creating potential cloning vehicles for exchanging genetic information between E. coli and T. ferrooxidans. Evidence from restriction enzyme analysis and Southern blot DNA-DNA hybridization indicates that the three native plasmids share little sequence homology.

  3. Genes and proteins of Escherichia coli (GenProtEc).

    PubMed

    Riley, M; Space, D B

    1996-01-01

    GenProtEc is a database of Escherichia coli genes and their gene products, classified by type of function and physiological role and with citations to the literature for each. Also present are data on sequence similarities among E.coli proteins with PAM values, percent identity of amino acids, length of alignment and percent aligned. The database is available as a PKZip file by ftp from mbl.edu/pub/ecoli.exe. The program runs under MS-DOS on IMB-compatible machines. GenProtEc can also be accessed through the World Wide Web at URL http://mbl.edu/html/ecoli.html. PMID:8594596

  4. Recombinant protein expression in Escherichia coli: advances and challenges

    PubMed Central

    Rosano, Germán L.; Ceccarelli, Eduardo A.

    2014-01-01

    Escherichia coli is one of the organisms of choice for the production of recombinant proteins. Its use as a cell factory is well-established and it has become the most popular expression platform. For this reason, there are many molecular tools and protocols at hand for the high-level production of heterologous proteins, such as a vast catalog of expression plasmids, a great number of engineered strains and many cultivation strategies. We review the different approaches for the synthesis of recombinant proteins in E. coli and discuss recent progress in this ever-growing field. PMID:24860555

  5. Escherichia coli as a model active colloid: A practical introduction.

    PubMed

    Schwarz-Linek, Jana; Arlt, Jochen; Jepson, Alys; Dawson, Angela; Vissers, Teun; Miroli, Dario; Pilizota, Teuta; Martinez, Vincent A; Poon, Wilson C K

    2016-01-01

    The flagellated bacterium Escherichia coli is increasingly used experimentally as a self-propelled swimmer. To obtain meaningful, quantitative results that are comparable between different laboratories, reproducible protocols are needed to control, 'tune' and monitor the swimming behaviour of these motile cells. We critically review the knowledge needed to do so, explain methods for characterising the colloidal and motile properties of E. coli cells, and propose a protocol for keeping them swimming at constant speed at finite bulk concentrations. In the process of establishing this protocol, we use motility as a high-throughput probe of aspects of cellular physiology via the coupling between swimming speed and the proton motive force.

  6. Advances in Molecular Serotyping and Subtyping of Escherichia coli.

    PubMed

    Fratamico, Pina M; DebRoy, Chitrita; Liu, Yanhong; Needleman, David S; Baranzoni, Gian Marco; Feng, Peter

    2016-01-01

    Escherichia coli plays an important role as a member of the gut microbiota; however, pathogenic strains also exist, including various diarrheagenic E. coli pathotypes and extraintestinal pathogenic E. coli that cause illness outside of the GI-tract. E. coli have traditionally been serotyped using antisera against the ca. 186 O-antigens and 53 H-flagellar antigens. Phenotypic methods, including bacteriophage typing and O- and H- serotyping for differentiating and characterizing E. coli have been used for many years; however, these methods are generally time consuming and not always accurate. Advances in next generation sequencing technologies have made it possible to develop genetic-based subtyping and molecular serotyping methods for E. coli, which are more discriminatory compared to phenotypic typing methods. Furthermore, whole genome sequencing (WGS) of E. coli is replacing established subtyping methods such as pulsed-field gel electrophoresis, providing a major advancement in the ability to investigate food-borne disease outbreaks and for trace-back to sources. A variety of sequence analysis tools and bioinformatic pipelines are being developed to analyze the vast amount of data generated by WGS and to obtain specific information such as O- and H-group determination and the presence of virulence genes and other genetic markers.

  7. Advances in molecular serotyping and subtyping of Escherichia coli

    DOE PAGES

    Fratamico, Pina M.; DebRoy, Chitrita; Liu, Yanhong; Needleman, David S.; Baranzoni, Gian Marco; Feng, Peter

    2016-05-03

    Escherichia coli plays an important role as a member of the gut microbiota; however, pathogenic strains also exist, including various diarrheagenic E. coli pathotypes and extraintestinal pathogenic E. coli that cause illness outside of the GI-tract. E. coli have traditionally been serotyped using antisera against the ca. 186 O-antigens and 53 H-flagellar antigens. Phenotypic methods, including bacteriophage typing and O- and H- serotyping for differentiating and characterizing E. coli have been used for many years; however, these methods are generally time consuming and not always accurate. Advances in next generation sequencing technologies have made it possible to develop genetic-based subtypingmore » and molecular serotyping methods for E. coli, which are more discriminatory compared to phenotypic typing methods. Furthermore, whole genome sequencing (WGS) of E. coli is replacing established subtyping methods such as pulsedfield gel electrophoresis, providing a major advancement in the ability to investigate food-borne disease outbreaks and for trace-back to sources. Furthermore, a variety of sequence analysis tools and bioinformatic pipelines are being developed to analyze the vast amount of data generated by WGS and to obtain specific information such as O- and H-group determination and the presence of virulence genes and other genetic markers.« less

  8. Gentamicin resistance among Escherichia coli strains isolated in neonatal sepsis.

    PubMed

    Hasvold, J; Bradford, L; Nelson, C; Harrison, C; Attar, M; Stillwell, T

    2013-01-01

    Neonatal sepsis is a significant cause of morbidity and mortality among term and preterm infants. Ampicillin and gentamicin are standard empiric therapy for early onset sepsis. Four cases of neonatal sepsis secondary to Escherichia coli (E. coli) found to be gentamicin resistant occurred within a five week period in one neonatal intensive care unit (NICU). To determine whether these cases could be tied to a single vector of transmission, and to more broadly evaluate the incidence of gentamicin resistant strains of E. coli in the neonatal population at our institution compared to other centers, we reviewed the charts of the four neonates (Infants A through D) and their mothers. The E. coli isolates were sent for Pulse Field Gel Electrophoresis (PFGE) to evaluate for genetic similarity between strains. We also reviewed all positive E. coli cultures from one NICU over a two year period. Infants A and B had genetically indistinguishable strains which matched that of urine and placental cultures of Infant B's mother. Infant C had a genetically distinct organism. Infant D, the identical twin of Infant C, did not have typing performed. Review of all cultures positive for E. coli at our institution showed a 12.9 percent incidence of gentamicin-resistance. A review of other studies showed that rates of resistance vary considerably by institution. We conclude that gentamicin-resistant E. coli is a relatively uncommon cause of neonatal sepsis, but should remain a consideration in patients who deteriorate despite initiation of empiric antibiotics. PMID:24246520

  9. Inactivation of Escherichia coli using atmospheric-pressure plasma jet

    NASA Astrophysics Data System (ADS)

    Kuwahata, Hiroshi; Yamaguchi, Takeshi; Ohyama, Ryu-ichiro; Ito, Atsushi

    2015-01-01

    An atmospheric-pressure argon (Ar) plasma jet was applied to the inactivation of Escherichia coli. The Ar plasma jet was generated at a frequency of 10 kHz, an applied voltage of 10 kV, and an Ar gas flow rate of 10 L/min at atmospheric pressure. E. coli cells seeded on an agar medium in a Petri dish were inactivated by Ar plasma jet irradiation for 1 s. Scanning electron microscopy (SEM) revealed that E. coli cells were killed because their cell wall and membrane were disrupted. To determine the causes of the disruption of the cell wall and membrane of E. coli, we performed the following experiments: the measurement of the surface temperature of an agar medium using a thermograph, the analysis of an emission spectrum of a plasma jet obtained using a multichannel spectrometer, and the determination of the distribution of the concentration of hydrogen peroxide (H2O2) generated on an agar medium by plasma jet irradiation using semiquantitative test strips. Moreover, H2O2 solutions of different concentrations were dropped onto an agar medium seeded with E. coli cells to examine the contribution of H2O2 to the death of E. coli. The results of these experiments showed that the cell wall and membrane of E. coli were disrupted by electrons in the plasma jet, as well as by electroneutral excited nitrogen molecules (N2) and hydroxyl (OH) radicals in the periphery of the plasma jet.

  10. Thiolases of Escherichia coli: purification and chain length specificities.

    PubMed Central

    Feigenbaum, J; Schulz, H

    1975-01-01

    The presence of only one thiolase (EC 2.3.1.9) in wild-type Escherichia coli induced for enzymes of beta oxidation was demonstrated. A different thiolase was shown to be present in a mutant constitutive for the enzymes of butyrate degradation. The two thiolases were purified to near homogeneity by a simple two-step procedure and were found to be associated with different proteins as shown by gel electrophoresis. The thiolase isolated from induced wild-type Escherichia coli cell was active on beta-ketoacyl-coenzyme A derivatives containing 4 to 16 carbons, but exhibited optimal activity with medium-chain substrates. In contrast, the thiolase isolated from the constitutive mutant was shown to be specific for acetoacetyl-coenzyme A. PMID:236278

  11. Biogenesis of inner membrane proteins in Escherichia coli.

    PubMed

    Luirink, Joen; Yu, Zhong; Wagner, Samuel; de Gier, Jan-Willem

    2012-06-01

    The inner membrane proteome of the model organism Escherichia coli is composed of inner membrane proteins, lipoproteins and peripherally attached soluble proteins. Our knowledge of the biogenesis of inner membrane proteins is rapidly increasing. This is in particular true for the early steps of biogenesis - protein targeting to and insertion into the membrane. However, our knowledge of inner membrane protein folding and quality control is still fragmentary. Furthering our knowledge in these areas will bring us closer to understand the biogenesis of individual inner membrane proteins in the context of the biogenesis of the inner membrane proteome of Escherichia coli as a whole. This article is part of a Special Issue entitled: Biogenesis/Assembly of Respiratory Enzyme Complexes.

  12. Mechanobiology of Antimicrobial Resistant Escherichia coli and Listeria innocua.

    PubMed

    Tajkarimi, Mehrdad; Harrison, Scott H; Hung, Albert M; Graves, Joseph L

    2016-01-01

    A majority of antibiotic-resistant bacterial infections in the United States are associated with biofilms. Nanoscale biophysical measures are increasingly revealing that adhesive and viscoelastic properties of bacteria play essential roles across multiple stages of biofilm development. Atomic Force Microscopy (AFM) applied to strains with variation in antimicrobial resistance enables new opportunities for investigating the function of adhesive forces (stickiness) in biofilm formation. AFM force spectroscopy analysis of a field strain of Listeria innocua and the strain Escherichia coli K-12 MG1655 revealed differing adhesive forces between antimicrobial resistant and nonresistant strains. Significant increases in stickiness were found at the nanonewton level for strains of Listeria innocua and Escherichia coli in association with benzalkonium chloride and silver nanoparticle resistance respectively. This advancement in the usage of AFM provides for a fast and reliable avenue for analyzing antimicrobial resistant cells and the molecular dynamics of biofilm formation as a protective mechanism.

  13. Mechanobiology of Antimicrobial Resistant Escherichia coli and Listeria innocua.

    PubMed

    Tajkarimi, Mehrdad; Harrison, Scott H; Hung, Albert M; Graves, Joseph L

    2016-01-01

    A majority of antibiotic-resistant bacterial infections in the United States are associated with biofilms. Nanoscale biophysical measures are increasingly revealing that adhesive and viscoelastic properties of bacteria play essential roles across multiple stages of biofilm development. Atomic Force Microscopy (AFM) applied to strains with variation in antimicrobial resistance enables new opportunities for investigating the function of adhesive forces (stickiness) in biofilm formation. AFM force spectroscopy analysis of a field strain of Listeria innocua and the strain Escherichia coli K-12 MG1655 revealed differing adhesive forces between antimicrobial resistant and nonresistant strains. Significant increases in stickiness were found at the nanonewton level for strains of Listeria innocua and Escherichia coli in association with benzalkonium chloride and silver nanoparticle resistance respectively. This advancement in the usage of AFM provides for a fast and reliable avenue for analyzing antimicrobial resistant cells and the molecular dynamics of biofilm formation as a protective mechanism. PMID:26914334

  14. Mechanobiology of Antimicrobial Resistant Escherichia coli and Listeria innocua

    PubMed Central

    Tajkarimi, Mehrdad; Harrison, Scott H.; Hung, Albert M.; Graves, Joseph L.

    2016-01-01

    A majority of antibiotic-resistant bacterial infections in the United States are associated with biofilms. Nanoscale biophysical measures are increasingly revealing that adhesive and viscoelastic properties of bacteria play essential roles across multiple stages of biofilm development. Atomic Force Microscopy (AFM) applied to strains with variation in antimicrobial resistance enables new opportunities for investigating the function of adhesive forces (stickiness) in biofilm formation. AFM force spectroscopy analysis of a field strain of Listeria innocua and the strain Escherichia coli K-12 MG1655 revealed differing adhesive forces between antimicrobial resistant and nonresistant strains. Significant increases in stickiness were found at the nanonewton level for strains of Listeria innocua and Escherichia coli in association with benzalkonium chloride and silver nanoparticle resistance respectively. This advancement in the usage of AFM provides for a fast and reliable avenue for analyzing antimicrobial resistant cells and the molecular dynamics of biofilm formation as a protective mechanism. PMID:26914334

  15. Complementation analysis of eleven tryptophanase mutations in Escherichia coli.

    PubMed

    White, M K; Yudkin, M D

    1979-10-01

    Nine independent mutants deficient in tryptophanase activity were isolated. Each mutation was transferred to a specialized transducing phage that carries the tryptophanase region of the Escherichia coli chromosome. The nine phages thus produced, and a tenth carrying a previously characterized tryptophanase mutation, were used to lysogenize a bacterial strain harbouring a mutation in the tryptophanase structural gene and also a suppressor of polarity. In no case was complementation observed; we conclude that there is no closely linked positive regulatory gene for tryptophanase.

  16. Current perspectivesin pathogenesis and antimicrobial resistance of enteroaggregative Escherichia coli.

    PubMed

    Kong, Haishen; Hong, Xiaoping; Li, Xuefen

    2015-08-01

    Enteroaggregative Escherichia coli (EAEC) is an emerging pathogen that causes acute and persistent diarrhea in children and adults. While the pathogenic mechanisms of EAEC intestinal colonization have been uncovered (including bacterial adhesion, enterotoxin and cytotoxin secretion, and stimulation of mucosal inflammation), those of severe extraintestinal infections remain largely unknown. The recent emergence of multidrug resistant EAEC represents an alarming public health threat and clinical challenge, and research on the molecular mechanisms of resistance is urgently needed.

  17. Electric field induced bacterial flocculation of Enteroaggregative Escherichia coli 042

    SciTech Connect

    Kumar, Aloke; Mortensen, Ninell P; Mukherjee, Partha P; Retterer, Scott T; Doktycz, Mitchel John

    2011-01-01

    A response of the aggregation dynamics of enteroaggregative Escherichia coli under low magnitude steady and oscillating electric fields is presented. The presence of uniform electric fields hampered microbial adhesion and biofilm formation on a transverse glass surface, but instead promoted the formation of flocs. Extremely heterogeneous distribution of live and dead cells was observed among the flocs. Moreover, floc formation was largely observed to be independent of the frequency of alternating electric fields.

  18. Escherichia coli and Salmonella 2000: the View From Here

    PubMed Central

    Schaechter, Moselio

    2001-01-01

    Five years after the publication of the second edition of the reference book Escherichia coli and Salmonella: Cellular and Molecular Biology, and on the eve of launching a successor venture, the editors and colleagues examine where we stand in our quest for an understanding of these organisms. The main areas selected for this brief inquiry are genomics, evolution, molecular multifunctionality, functional backups, regulation of gene expression, cell biology, sensing of the environment, and ecology. PMID:11238988

  19. Shear alters motility of Escherichia coli

    NASA Astrophysics Data System (ADS)

    Molaei, Mehdi; Jalali, Maryam; Sheng, Jian

    2013-11-01

    Understanding of locomotion of microorganisms in shear flows drew a wide range of interests in microbial related topics such as biological process including pathogenic infection and biophysical interactions like biofilm formation on engineering surfaces. We employed microfluidics and digital holography microscopy to study motility of E. coli in shear flows. We controlled the shear flow in three different shear rates: 0.28 s-1, 2.8 s-1, and 28 s-1 in a straight channel with the depth of 200 μm. Magnified holograms, recorded at 15 fps with a CCD camera over more than 20 minutes, are analyzed to obtain 3D swimming trajectories and subsequently used to extract shear responses of E.coli. Thousands of 3-D bacterial trajectories are tracked. The change of bacteria swimming characteristics including swimming velocity, reorientation, and dispersion coefficient are computed directly for individual trajectory and ensemble averaged over thousands of realizations. The results show that shear suppresses the bacterial dispersions in bulk but promote dispersions near the surface contrary to those in quiescent flow condition. Ongoing analyses are focusing to quantify effect of shear rates on tumbling frequency and reorientation of cell body, and its implication in locating the hydrodynamic mechanisms for shear enhanced angular scattering. NIH, NSF, GoMRI.

  20. Biomolecular Mechanisms of Pseudomonas aeruginosa and Escherichia coli Biofilm Formation

    PubMed Central

    Laverty, Garry; Gorman, Sean P.; Gilmore, Brendan F.

    2014-01-01

    Pseudomonas aeruginosa and Escherichia coli are the most prevalent Gram-negative biofilm forming medical device associated pathogens, particularly with respect to catheter associated urinary tract infections. In a similar manner to Gram-positive bacteria, Gram-negative biofilm formation is fundamentally determined by a series of steps outlined more fully in this review, namely adhesion, cellular aggregation, and the production of an extracellular polymeric matrix. More specifically this review will explore the biosynthesis and role of pili and flagella in Gram-negative adhesion and accumulation on surfaces in Pseudomonas aeruginosa and Escherichia coli. The process of biofilm maturation is compared and contrasted in both species, namely the production of the exopolysaccharides via the polysaccharide synthesis locus (Psl), pellicle Formation (Pel) and alginic acid synthesis in Pseudomonas aeruginosa, and UDP-4-amino-4-deoxy-l-arabinose and colonic acid synthesis in Escherichia coli. An emphasis is placed on the importance of the LuxR homologue sdiA; the luxS/autoinducer-II; an autoinducer-III/epinephrine/norepinephrine and indole mediated Quorum sensing systems in enabling Gram-negative bacteria to adapt to their environments. The majority of Gram-negative biofilms consist of polysaccharides of a simple sugar structure (either homo- or heteropolysaccharides) that provide an optimum environment for the survival and maturation of bacteria, allowing them to display increased resistance to antibiotics and predation. PMID:25438014

  1. Biomolecular Mechanisms of Pseudomonas aeruginosa and Escherichia coli Biofilm Formation.

    PubMed

    Laverty, Garry; Gorman, Sean P; Gilmore, Brendan F

    2014-07-18

    Pseudomonas aeruginosa and Escherichia coli are the most prevalent Gram-negative biofilm forming medical device associated pathogens, particularly with respect to catheter associated urinary tract infections. In a similar manner to Gram-positive bacteria, Gram-negative biofilm formation is fundamentally determined by a series of steps outlined more fully in this review, namely adhesion, cellular aggregation, and the production of an extracellular polymeric matrix. More specifically this review will explore the biosynthesis and role of pili and flagella in Gram-negative adhesion and accumulation on surfaces in Pseudomonas aeruginosa and Escherichia coli. The process of biofilm maturation is compared and contrasted in both species, namely the production of the exopolysaccharides via the polysaccharide synthesis locus (Psl), pellicle Formation (Pel) and alginic acid synthesis in Pseudomonas aeruginosa, and UDP-4-amino-4-deoxy-l-arabinose and colonic acid synthesis in Escherichia coli. An emphasis is placed on the importance of the LuxR homologue sdiA; the luxS/autoinducer-II; an autoinducer-III/epinephrine/norepinephrine and indole mediated Quorum sensing systems in enabling Gram-negative bacteria to adapt to their environments. The majority of Gram-negative biofilms consist of polysaccharides of a simple sugar structure (either homo- or heteropolysaccharides) that provide an optimum environment for the survival and maturation of bacteria, allowing them to display increased resistance to antibiotics and predation.

  2. The Genome Sequence of Avian Pathogenic Escherichia coli Strain O1:K1:H7 Shares Strong Similarities with Human Extraintestinal Pathogenic E. coli Genomes▿

    PubMed Central

    Johnson, Timothy J.; Kariyawasam, Subhashinie; Wannemuehler, Yvonne; Mangiamele, Paul; Johnson, Sara J.; Doetkott, Curt; Skyberg, Jerod A.; Lynne, Aaron M.; Johnson, James R.; Nolan, Lisa K.

    2007-01-01

    Escherichia coli strains that cause disease outside the intestine are known as extraintestinal pathogenic E. coli (ExPEC) and include human uropathogenic E. coli (UPEC) and avian pathogenic E. coli (APEC). Regardless of host of origin, ExPEC strains share many traits. It has been suggested that these commonalities may enable APEC to cause disease in humans. Here, we begin to test the hypothesis that certain APEC strains possess potential to cause human urinary tract infection through virulence genotyping of 1,000 APEC and UPEC strains, generation of the first complete genomic sequence of an APEC (APEC O1:K1:H7) strain, and comparison of this genome to all available human ExPEC genomic sequences. The genomes of APEC O1 and three human UPEC strains were found to be remarkably similar, with only 4.5% of APEC O1's genome not found in other sequenced ExPEC genomes. Also, use of multilocus sequence typing showed that some of the sequenced human ExPEC strains were more like APEC O1 than other human ExPEC strains. This work provides evidence that at least some human and avian ExPEC strains are highly similar to one another, and it supports the possibility that a food-borne link between some APEC and UPEC strains exists. Future studies are necessary to assess the ability of APEC to overcome the hurdles necessary for such a food-borne transmission, and epidemiological studies are required to confirm that such a phenomenon actually occurs. PMID:17293413

  3. Adhesion of Human and Animal Escherichia coli Strains in Association with Their Virulence-Associated Genes and Phylogenetic Origins

    PubMed Central

    Frömmel, Ulrike; Lehmann, Werner; Rödiger, Stefan; Böhm, Alexander; Nitschke, Jörg; Weinreich, Jörg; Groß, Julia; Roggenbuck, Dirk; Zinke, Olaf; Ansorge, Hermann; Vogel, Steffen; Klemm, Per; Wex, Thomas; Schröder, Christian; Wieler, Lothar H.

    2013-01-01

    Intestinal colonization is influenced by the ability of the bacterium to inhabit a niche, which is based on the expression of colonization factors. Escherichia coli carries a broad range of virulence-associated genes (VAGs) which contribute to intestinal (inVAGs) and extraintestinal (exVAGs) infection. Moreover, initial evidence indicates that inVAGs and exVAGs support intestinal colonization. We developed new screening tools to genotypically and phenotypically characterize E. coli isolates originating in humans, domestic pigs, and 17 wild mammal and avian species. We analyzed 317 isolates for the occurrence of 44 VAGs using a novel multiplex PCR microbead assay (MPMA) and for adhesion to four epithelial cell lines using a new adhesion assay. We correlated data for the definition of new adhesion genes. inVAGs were identified only sporadically, particularly in roe deer (Capreolus capreolus) and the European hedgehog ( Erinaceus europaeus). The prevalence of exVAGs depended on isolation from a specific host. Human uropathogenic E. coli isolates carried exVAGs with the highest prevalence, followed by badger (Meles meles) and roe deer isolates. Adhesion was found to be very diverse. Adhesion was specific to cells, host, and tissue, though it was also unspecific. Occurrence of the following VAGs was associated with a higher rate of adhesion to one or more cell lines: afa-dra, daaD, tsh, vat, ibeA, fyuA, mat, sfa-foc, malX, pic, irp2, and papC. In summary, we established new screening methods which enabled us to characterize large numbers of E. coli isolates. We defined reservoirs for potential pathogenic E. coli. We also identified a very broad range of colonization strategies and defined potential new adhesion genes. PMID:23872574

  4. Adhesion of human and animal Escherichia coli strains in association with their virulence-associated genes and phylogenetic origins.

    PubMed

    Frömmel, Ulrike; Lehmann, Werner; Rödiger, Stefan; Böhm, Alexander; Nitschke, Jörg; Weinreich, Jörg; Groß, Julia; Roggenbuck, Dirk; Zinke, Olaf; Ansorge, Hermann; Vogel, Steffen; Klemm, Per; Wex, Thomas; Schröder, Christian; Wieler, Lothar H; Schierack, Peter

    2013-10-01

    Intestinal colonization is influenced by the ability of the bacterium to inhabit a niche, which is based on the expression of colonization factors. Escherichia coli carries a broad range of virulence-associated genes (VAGs) which contribute to intestinal (inVAGs) and extraintestinal (exVAGs) infection. Moreover, initial evidence indicates that inVAGs and exVAGs support intestinal colonization. We developed new screening tools to genotypically and phenotypically characterize E. coli isolates originating in humans, domestic pigs, and 17 wild mammal and avian species. We analyzed 317 isolates for the occurrence of 44 VAGs using a novel multiplex PCR microbead assay (MPMA) and for adhesion to four epithelial cell lines using a new adhesion assay. We correlated data for the definition of new adhesion genes. inVAGs were identified only sporadically, particularly in roe deer (Capreolus capreolus) and the European hedgehog ( Erinaceus europaeus). The prevalence of exVAGs depended on isolation from a specific host. Human uropathogenic E. coli isolates carried exVAGs with the highest prevalence, followed by badger (Meles meles) and roe deer isolates. Adhesion was found to be very diverse. Adhesion was specific to cells, host, and tissue, though it was also unspecific. Occurrence of the following VAGs was associated with a higher rate of adhesion to one or more cell lines: afa-dra, daaD, tsh, vat, ibeA, fyuA, mat, sfa-foc, malX, pic, irp2, and papC. In summary, we established new screening methods which enabled us to characterize large numbers of E. coli isolates. We defined reservoirs for potential pathogenic E. coli. We also identified a very broad range of colonization strategies and defined potential new adhesion genes.

  5. Survival of Escherichia coli on strawberries grown under greenhouse conditions.

    PubMed

    Shaw, Angela Laury; Svoboda, Amanda; Jie, Beatrice; Nonnecke, Gail; Mendonca, Aubrey

    2015-04-01

    Strawberries are soft fruit that are not recommended to have a post-harvest wash due to quality concerns. Escherichia coli O157:H7 has been linked to outbreaks with strawberries but little is known about the survival of E. coli during the growth cycle of strawberries. The survival of E. coli on strawberry plants during growing under greenhouses conditions was evaluated. Soil, leaves, and strawberries (if present) were artificially contaminated with an E. coli surrogate either at the time of planting, first runner removal (4 wk), second runner removal (8 wk), or one week prior to harvest. At harvest E. coli was recovered from the leaves, soil, and strawberries regardless of the contamination time. Time of contamination influenced (P < 0.05) numbers of viable E. coli on the plant. The highest survival of E. coli (P < 0.0001) was detected in soil that was contaminated at planting (4.27 log10 CFU g soil(-1)), whereas, the survival of E. coli was maximal at later contamination times (8 wk and 1 wk prior to harvest) for the leaves (4.40 and 4.68 log10 CFU g leaves(-1)) and strawberries (3.37 and 3.53 log10 CFU strawberry(-1)). Cross contamination from leaves to fruit was observed during this study, with the presence of E. coli on strawberries which had not been present at the time of contamination. These results indicate that good agricultural best practices to avoid contamination are necessary to minimize the risk of contamination of these popular fruit with enteric pathogens. Practices should include soil testing prior to harvest and avoiding contamination of the leaves.

  6. Fluorogenic assays for immediate confirmation of Escherichia coli.

    PubMed

    Feng, P C; Hartman, P A

    1982-06-01

    Rapid assays for Escherichia coli were developed by using the compound 4-methylumbelliferone glucuronide (MUG), which is hydrolyzed by glucuronidase to yield a fluorogenic product. The production of glucuronidase was limited to strains of E. coli and some Salmonella and Shigella strains in the family Enterobacteriaceae. For immediate confirmation of the presence of E. coli in most-probable-number tubes, MUG was incorporated into lauryl tryptose broth at a final concentration of 100 micrograms/ml. Results of both the presumptive test (gas production) and the confirmed test (fluorescence) for E. coli were obtained from a variety of food, water, and milk samples after incubation for only 24 h at 35 degrees C. Approximately 90% of the tubes showing both gas production and fluorescence contained fecal coliforms (they were positive in EC broth incubated at 45 degrees C). Few false-positive reactions were observed. The lauryl tryptose broth-MUG-most-probable-number assay was superior to violet red bile agar for the detection of heat- and chlorine-injured E. coli cells. Anaerogenic strains produced positive reactions, and small numbers of E. coli could be detected in the presence of large numbers of competing bacteria. The fluorogenic assay was sensitive and rapid; the presence of one viable cell was detected within 20 h. E. coli colonies could be distinguished from other coliforms on membrane filters and plates of violet red bile agar if MUG was incorporated into the culture media. A rapid confirmatory test for E. coli that is amenable to automation was developed by using microtitration plates filled with a nonselective medium containing MUG. Pure or mixed cultures containing E. coli produced fluorescence within 4 h (most strains) to 24 h (a few weakly positive strains).

  7. Survival of Escherichia coli on strawberries grown under greenhouse conditions.

    PubMed

    Shaw, Angela Laury; Svoboda, Amanda; Jie, Beatrice; Nonnecke, Gail; Mendonca, Aubrey

    2015-04-01

    Strawberries are soft fruit that are not recommended to have a post-harvest wash due to quality concerns. Escherichia coli O157:H7 has been linked to outbreaks with strawberries but little is known about the survival of E. coli during the growth cycle of strawberries. The survival of E. coli on strawberry plants during growing under greenhouses conditions was evaluated. Soil, leaves, and strawberries (if present) were artificially contaminated with an E. coli surrogate either at the time of planting, first runner removal (4 wk), second runner removal (8 wk), or one week prior to harvest. At harvest E. coli was recovered from the leaves, soil, and strawberries regardless of the contamination time. Time of contamination influenced (P < 0.05) numbers of viable E. coli on the plant. The highest survival of E. coli (P < 0.0001) was detected in soil that was contaminated at planting (4.27 log10 CFU g soil(-1)), whereas, the survival of E. coli was maximal at later contamination times (8 wk and 1 wk prior to harvest) for the leaves (4.40 and 4.68 log10 CFU g leaves(-1)) and strawberries (3.37 and 3.53 log10 CFU strawberry(-1)). Cross contamination from leaves to fruit was observed during this study, with the presence of E. coli on strawberries which had not been present at the time of contamination. These results indicate that good agricultural best practices to avoid contamination are necessary to minimize the risk of contamination of these popular fruit with enteric pathogens. Practices should include soil testing prior to harvest and avoiding contamination of the leaves. PMID:25475285

  8. Preparation of Soluble Proteins from Escherichia coli

    PubMed Central

    Wingfield, Paul T.

    2014-01-01

    Purification of human IL-1β is used in this unit as an example of the preparation of soluble proteins from E. coli. Bacteria containing IL-1β are lysed, and IL-1 β in the resulting supernatant is purified by anion-exchange chromatography, salt precipitation and cation-exchange chromatography, and then concentrated. Finally, the IL-1 β protein is applied to a gel-filtration column to separate it from remaining higher- and lower-molecular-weight contaminants, the purified protein is stored frozen or is lyophilized. The purification protocol described is typical for a protein that is expressed in fairly high abundance (i.e., >5% total protein) and accumulates in a soluble state. Also, the purification procedure serves as an example of how use classical protein purifications methods which may also be used in conjunction with the affinity-based methods now more commonly used. PMID:25367009

  9. Preparation of Soluble Proteins from Escherichia coli.

    PubMed

    Wingfield, Paul T

    2014-01-01

    Purification of human IL-1β is used in this unit as an example of the preparation of a soluble protein from E. coli. Bacteria containing IL-1β are lysed, and IL-1 β in the resulting supernatant is purified by anion-exchange chromatography, salt precipitation, and cation-exchange chromatography, and then concentrated. Finally, the IL-1 β protein is applied to a gel-filtration column to separate it from remaining higher- and lower-molecular-weight contaminants, the purified protein is stored frozen or is lyophilized. The purification protocol described is typical for a protein that is expressed in fairly high abundance (i.e., >5% total protein) and accumulates in a soluble state. In addition, the purification procedure serves as an example of how to use classical protein purifications methods, which may also be used in conjunction with the affinity-based methods now more commonly used. PMID:25367009

  10. EcoCyc: A comprehensive view of Escherichia coli biology

    PubMed Central

    Keseler, Ingrid M.; Bonavides-Martínez, César; Collado-Vides, Julio; Gama-Castro, Socorro; Gunsalus, Robert P.; Johnson, D. Aaron; Krummenacker, Markus; Nolan, Laura M.; Paley, Suzanne; Paulsen, Ian T.; Peralta-Gil, Martin; Santos-Zavaleta, Alberto; Shearer, Alexander Glennon; Karp, Peter D.

    2009-01-01

    EcoCyc (http://EcoCyc.org) provides a comprehensive encyclopedia of Escherichia coli biology. EcoCyc integrates information about the genome, genes and gene products; the metabolic network; and the regulatory network of E. coli. Recent EcoCyc developments include a new initiative to represent and curate all types of E. coli regulatory processes such as attenuation and regulation by small RNAs. EcoCyc has started to curate Gene Ontology (GO) terms for E. coli and has made a dataset of E. coli GO terms available through the GO Web site. The curation and visualization of electron transfer processes has been significantly improved. Other software and Web site enhancements include the addition of tracks to the EcoCyc genome browser, in particular a type of track designed for the display of ChIP-chip datasets, and the development of a comparative genome browser. A new Genome Omics Viewer enables users to paint omics datasets onto the full E. coli genome for analysis. A new advanced query page guides users in interactively constructing complex database queries against EcoCyc. A Macintosh version of EcoCyc is now available. A series of Webinars is available to instruct users in the use of EcoCyc. PMID:18974181

  11. Transformation of Escherichia coli and protein expression using lipoplex mimicry.

    PubMed

    Yun, Chul-Ho; Bae, Chun-Sik; Ahn, Taeho

    2016-11-01

    We investigated a "one-step" method for transformation of and protein expression in Escherichia coli (E. coli) using a complex of n-stearylamine, a cationic lipid, and plasmid DNA, which mimics lipoplex-based approaches. When E. coli cells were treated with the cationic lipid-plasmid complex, the transformation efficiencies were in the range of approximately 2-3 × 10(6) colony-forming units. Further increase in the efficiency was obtained by co-treatment with calcium chloride (or rubidium chloride) and the complexes. Moreover, after DNA transfer, E. coli cells successfully expressed plasmid-encoded proteins such as cytochrome P450s and glutathione-S-transferase without overnight incubation of the cells to form colonies, an indispensable step in other bacterial transformation methods. In this study, we provide a simple method for E. coli transformation, which does not require the preparation of competent cells. The present method also shortens the overall procedures for transformation and gene expression in E. coli by omitting the colony-forming step. PMID:27416742

  12. Bacterial chemotaxis differences in Escherichia coli isolated from different hosts.

    PubMed

    Dzinic, Sijana H; Luercio, Marcella; Ram, Jeffrey L

    2008-12-01

    The mechanisms mediating the association between Escherichia coli and specific hosts are unknown. This study investigates the hypothesis that the host-specific associations of E. coli strains are mediated in part by differences in chemotaxis. To test this hypothesis, chemotactic responses of E. coli strains isolated from different host groups (carnivores, herbivores, and omnivores) were tested with various attractants. In low-density agar chemotaxis assays, the average motility of E. coli in response to aspartate, serine, and ribose among the different groups was not significantly different; however, strains from carnivores responded significantly more to aspartate, relative to their responses to serine, in comparison with strains from herbivores, which responded equally or better to serine than to aspartate. The relatively greater chemotactic response of strains from carnivores to aspartate than to serine was confirmed in a subset of strains by capillary chemotaxis assay. Differences in responses to serine and aspartate were not due to growth differences, as determined by comparison of 24 h growth curves with glycerol, aspartate, and serine carbon sources. The differences in chemotactic behavior of E. coli strains isolated from herbivores and carnivores support the hypothesis that host-specific associations of E. coli strains are mediated in part by differences in chemotactic behavior.

  13. Transformation of Escherichia coli and protein expression using lipoplex mimicry.

    PubMed

    Yun, Chul-Ho; Bae, Chun-Sik; Ahn, Taeho

    2016-11-01

    We investigated a "one-step" method for transformation of and protein expression in Escherichia coli (E. coli) using a complex of n-stearylamine, a cationic lipid, and plasmid DNA, which mimics lipoplex-based approaches. When E. coli cells were treated with the cationic lipid-plasmid complex, the transformation efficiencies were in the range of approximately 2-3 × 10(6) colony-forming units. Further increase in the efficiency was obtained by co-treatment with calcium chloride (or rubidium chloride) and the complexes. Moreover, after DNA transfer, E. coli cells successfully expressed plasmid-encoded proteins such as cytochrome P450s and glutathione-S-transferase without overnight incubation of the cells to form colonies, an indispensable step in other bacterial transformation methods. In this study, we provide a simple method for E. coli transformation, which does not require the preparation of competent cells. The present method also shortens the overall procedures for transformation and gene expression in E. coli by omitting the colony-forming step.

  14. Hybrid Structure of the Type 1 Pilus of Uropathogenic Escherichia coli.

    PubMed

    Habenstein, Birgit; Loquet, Antoine; Hwang, Songhwan; Giller, Karin; Vasa, Suresh Kumar; Becker, Stefan; Habeck, Michael; Lange, Adam

    2015-09-28

    Type 1 pili are filamentous protein assemblies on the surface of Gram-negative bacteria that mediate adhesion to host cells during the infection process. The molecular structure of type 1 pili remains elusive on the atomic scale owing to their insolubility and noncrystallinity. Herein we describe an approach for hybrid-structure determination that is based on data from solution-state NMR spectroscopy on the soluble subunit and solid-state NMR spectroscopy and STEM data on the assembled pilus. Our approach is based on iterative modeling driven by structural information extracted from different sources and provides a general tool to access pseudo atomic structures of protein assemblies with complex subunit folds. By using this methodology, we determined the local conformation of the FimA pilus subunit in the context of the assembled type 1 pilus, determined the exact helical pilus architecture, and elucidated the intermolecular interfaces contributing to pilus assembly and stability with atomic detail.

  15. Phylogenetic Analysis of Enteroaggregative and Diffusely Adherent Escherichia coli

    PubMed Central

    Czeczulin, John R.; Whittam, Thomas S.; Henderson, Ian R.; Navarro-Garcia, Fernando; Nataro, James P.

    1999-01-01

    The phylogenetics of the various pathotypes of diarrheagenic Escherichia coli are not completely understood. In this study, we identified several plasmid and chromosomal genes in the pathogenic enteroaggregative E. coli (EAEC) prototype strain 042 and determined the prevalence of these loci among EAEC and diffusely adherent E. coli strains. The distribution of these genes is analyzed within an evolutionary framework provided by the characterization of allelic variation in housekeeping genes via multilocus enzyme electrophoresis. Our data reveal that EAEC strains are heterogeneous with respect to chromosomal and plasmid-borne genes but that the majority harbor a member of a conserved family of virulence plasmids. Comparison of plasmid and chromosomal relatedness of strains suggests clonality of chromosomal markers and a limited transfer model of plasmid distribution. PMID:10338471

  16. Biofilm modifies expression of ribonucleotide reductase genes in Escherichia coli.

    PubMed

    Cendra, Maria del Mar; Juárez, Antonio; Torrents, Eduard

    2012-01-01

    Ribonucleotide reductase (RNR) is an essential enzyme for all living organisms since is the responsible for the last step in the synthesis of the four deoxyribonucleotides (dNTPs) necessary for DNA replication and repair. In this work, we have investigated the expression of the three-RNR classes (Ia, Ib and III) during Escherichia coli biofilm formation. We show the temporal and spatial importance of class Ib and III RNRs during this process in two different E. coli wild-type strains, the commensal MG1655 and the enteropathogenic and virulent E2348/69, the prototype for the enteropathogenic E. coli (EPEC). We have established that class Ib RNR, so far considered cryptic, play and important role during biofilm formation. The implication of this RNR class under the specific growth conditions of biofilm formation is discussed. PMID:23050019

  17. Incidence of Escherichia coli in black walnut meats.

    PubMed

    Meyer, M T; Vaughn, R H

    1969-11-01

    Examination of commercially shelled black walnut meats showed inconsistent numbers of total aerobic bacteria, coliforms, and Escherichia coli; variation occurred among different meat sizes and within each meat size. The incidence of E. coli on meats of commercially hulled black walnuts depended on the physical condition of the nuts. Apparently tightly sealed ones contained only a few or none, whereas those with visibly separated sutures and spoiled meats yielded the most. This contamination was in part correlated to a hulling operation. Large numbers of E. coli on the husk of the walnuts contaminated the hulling water, subsequently also contaminating the meats by way of separated sutures. Chlorination of the hulling wash water was ineffective. Attempts were made to decontaminate the walnut meats without subsequent deleterious changes in flavor or texture. A treatment in coconut oil at 100 C followed by removal of excess surface oil by centrifugation was best.

  18. Reconstruction of a chromatic response system in Escherichia coli.

    PubMed

    Sugie, Yoshimi; Hori, Mayuko; Oka, Shunsuke; Ohtsuka, Hokuto; Aiba, Hirofumi

    2016-07-14

    Two-component signal transduction systems (TCS) are involved in widespread cellular responses to diverse signals from bacteria to plants. Cyanobacteria have evolved photoperception systems for efficient photosynthesis, and some histidine kinases are known to function as photosensors. In this study, we attempt to reconstruct the photoperception system in Escherichia coli to make an easily controllable ON/OFF switch for gene expressions. For this purpose, a CcaS-CcaR two-component system from Nostoc punctiforme was expressed with phycocyanobilin (PCB) producing enzymes in E. coli which carries a G-box-controlled reporter gene. We succeeded to endow E. coli with a gene activation switch that is regulated in a light-color dependent manner. The possibility of such a switch for the development of synthetic biology is pointed out. PMID:27246537

  19. Chemotaxis towards autoinducer 2 mediates autoaggregation in Escherichia coli

    PubMed Central

    Laganenka, Leanid; Colin, Remy; Sourjik, Victor

    2016-01-01

    Bacteria communicate by producing and sensing extracellular signal molecules called autoinducers. Such intercellular signalling, known as quorum sensing, allows bacteria to coordinate and synchronize behavioural responses at high cell densities. Autoinducer 2 (AI-2) is the only known quorum-sensing molecule produced by Escherichia coli but its physiological role remains elusive, although it is known to regulate biofilm formation and virulence in other bacterial species. Here we show that chemotaxis towards self-produced AI-2 can mediate collective behaviour—autoaggregation—of E. coli. Autoaggregation requires motility and is strongly enhanced by chemotaxis to AI-2 at physiological cell densities. These effects are observed regardless whether cell–cell interactions under particular growth conditions are mediated by the major E. coli adhesin (antigen 43) or by curli fibres. Furthermore, AI-2-dependent autoaggregation enhances bacterial stress resistance and promotes biofilm formation. PMID:27687245

  20. Functions of the gene products of Escherichia coli.

    PubMed Central

    Riley, M

    1993-01-01

    A list of currently identified gene products of Escherichia coli is given, together with a bibliography that provides pointers to the literature on each gene product. A scheme to categorize cellular functions is used to classify the gene products of E. coli so far identified. A count shows that the numbers of genes concerned with small-molecule metabolism are on the same order as the numbers concerned with macromolecule biosynthesis and degradation. One large category is the category of tRNAs and their synthetases. Another is the category of transport elements. The categories of cell structure and cellular processes other than metabolism are smaller. Other subjects discussed are the occurrence in the E. coli genome of redundant pairs and groups of genes of identical or closely similar function, as well as variation in the degree of density of genetic information in different parts of the genome. PMID:7508076