Note: This page contains sample records for the topic uropathogenic escherichia coli from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: August 15, 2014.
1

Proteomic analysis of uropathogenic Escherichia coli.  

PubMed

Urinary tract infections (UTIs) are among the most common of bacterial infections in humans. Although a number of Gram-negative bacteria can cause UTIs, most cases are due to infection by uropathogenic E. coli (UPEC). Genomic studies have shown that UPEC encode a number of specialized activities that allow the bacteria to initiate and maintain infections in the environment of the urinary tract. Proteomic analyses have complemented the genomic data and have documented differential patterns of protein synthesis for bacteria growing ex vivo in human urine or recovered directly from the urinary tracts of infected mice. These studies provide valuable insights into the molecular basis of UPEC pathogenesis and have aided the identification of putative vaccine targets. Despite the substantial progress that has been achieved, many future challenges remain in the application of proteomics to provide a comprehensive view of bacterial pathogenesis in both acute and chronic UTIs. PMID:24393038

Cash, Phillip

2014-02-01

2

Growth of uropathogenic Escherichia coli strains at solid surfaces  

Microsoft Academic Search

The adhesion and growth of two catheter-associated (O2K2 and O83K?) and two non catheter-associated (O111K58 and 0157K-) uropathogenic Escherichia coli strains on glass, poly(methyl methacrylate) (PMMA), a negatively charged copolymer of MMA and methacrylic acid (MAA) and a positively charged copolymer of MMA and trimethylaminoethyl methacrylate chloride (TMAEMA-Cl) were studied. The solid surfaces were placed in a parallel plate perfusion

G. Harkes; J. Dankert; J. Feijen

1992-01-01

3

Modulation of Polymorphonuclear Neutrophil Function by Cytotoxic Necrotizing Factor Type 1 - Expressing Uropathogenic Escherichia coli.  

National Technical Information Service (NTIS)

Uropathogenic Escherichia coli (UPEC) cause more than 85% of all urinary tract infections (UTI). These infections primarily affect women, and over half of all women will experience at least one UTI in their lifetime. Animal models of UTI pathogenesis have...

J. M. Davis

2005-01-01

4

Intracellular bacterial communities of uropathogenic Escherichia coli in urinary tract pathogenesis  

Microsoft Academic Search

Urinary tract infections in young, healthy women frequently recur, despite their traditional classification as acute infections. Conventional wisdom dictates that uropathogens causing recurrent infections in such individuals come from the fecal or vaginal flora, in the same manner as the initial infection. However, recent studies of uropathogenic Escherichia coli have found that it can carry out a complex developmental program

Gregory G. Anderson; Karen W. Dodson; Thomas M. Hooton; Scott J. Hultgren

2004-01-01

5

Morphological plasticity promotes resistance to phagocyte killing of uropathogenic Escherichia coli  

PubMed Central

Uropathogenic Escherichia coli proceed through a complex intracellular developmental pathway that includes multiple morphological changes. During intracellular growth within Toll-like receptor 4-activated superficial bladder epithelial cells, a subpopulation of uropathogenic E. coli initiates SulA-mediated filamentation. In this study, we directly investigated the role of bacterial morphology in the survival of uropathogenic E. coli from killing by phagocytes. We initially determined that both polymorphonuclear neutrophils and macrophages are recruited to murine bladder epithelium at times coincident with extracellular bacillary and filamentous uropathogenic E. coli. We further determined that bacillary uropathogenic E. coli were preferentially destroyed when mixed uropathogenic E. coli populations were challenged with cultured murine macrophages in vitro. Consistent with studies using elliptical-shaped polymers, the initial point of contact between the phagocyte and filamentous uropathogenic E. coli influenced the efficacy of internalization. These findings demonstrate that filamentous morphology provides a selective advantage for uropathogenic E. coli evasion of killing by phagocytes and defines a mechanism for the essential role for SulA during bacterial cystitis. Thus, morphological plasticity can be viewed as a distinct class of mechanism used by bacterial pathogens to subvert host immunity.

Horvath, Dennis J.; Li, Birong; Casper, Travis; Partida-Sanchez, Santiago; Hunstad, David A.; Hultgren, Scott J.; Justice, Sheryl S.

2011-01-01

6

Bacteriophages with the Ability to Degrade Uropathogenic Escherichia Coli Biofilms  

PubMed Central

Escherichia coli-associated urinary tract infections (UTIs) are among the most common bacterial infections in humans. UTIs are usually managed with antibiotic therapy, but over the years, antibiotic-resistant strains of uropathogenic E. coli (UPEC) have emerged. The formation of biofilms further complicates the treatment of these infections by making them resistant to killing by the host immune system as well as by antibiotics. This has encouraged research into therapy using bacteriophages (phages) as a supplement or substitute for antibiotics. In this study we characterized 253 UPEC in terms of their biofilm-forming capabilities, serotype, and antimicrobial resistance. Three phages were then isolated (vB_EcoP_ACG-C91, vB_EcoM_ACG-C40 and vB_EcoS_ACG-M12) which were able to lyse 80.5% of a subset (42) of the UPEC strains able to form biofilms. Correlation was established between phage sensitivity and specific serotypes of the UPEC strains. The phages’ genome sequences were determined and resulted in classification of vB_EcoP_ACG-C91 as a SP6likevirus, vB_EcoM_ACG-C40 as a T4likevirus and vB_EcoS_ACG-M12 as T1likevirus. We assessed the ability of the three phages to eradicate the established biofilm of one of the UPEC strains used in the study. All phages significantly reduced the biofilm within 2–12 h of incubation.

Chibeu, Andrew; Lingohr, Erika J.; Masson, Luke; Manges, Amee; Harel, Josee; Ackermann, Hans-W.; Kropinski, Andrew M.; Boerlin, Patrick

2012-01-01

7

Forced resurgence and targeting of intracellular uropathogenic Escherichia coli reservoirs.  

PubMed

Intracellular quiescent reservoirs of uropathogenic Escherichia coli (UPEC), which can seed the bladder mucosa during the acute phase of a urinary tract infection (UTI), are protected from antibiotic treatments and are extremely difficult to eliminate. These reservoirs are a potential source for recurrent UTIs that affect millions annually. Here, using murine infection models and the bladder cell exfoliant chitosan, we demonstrate that intracellular UPEC populations shift within the stratified layers of the urothelium during the course of a UTI. Following invasion of the terminally differentiated superficial layer of epithelial cells that line the bladder lumen, UPEC can multiply and disseminate, eventually establishing reservoirs within underlying immature host cells. If given access, UPEC can invade the superficial and immature bladder cells equally well. As infected immature host cells differentiate and migrate towards the apical surface of the bladder, UPEC can reinitiate growth and discharge into the bladder lumen. By inducing the exfoliation of the superficial layers of the urothelium, chitosan stimulates rapid regenerative processes and the reactivation and efflux of quiescent intracellular UPEC reservoirs. When combined with antibiotics, chitosan treatment significantly reduces bacterial loads within the bladder and may therefore be of therapeutic value to individuals with chronic, recurrent UTIs. PMID:24667805

Blango, Matthew G; Ott, Elizabeth M; Erman, Andreja; Veranic, Peter; Mulvey, Matthew A

2014-01-01

8

Transposon Mutagenesis Identifies Uropathogenic Escherichia coli Biofilm Factors  

PubMed Central

Uropathogenic Escherichia coli (UPEC), which accounts for 85% of urinary tract infections (UTI), assembles biofilms in diverse environments, including the host. Besides forming biofilms on biotic surfaces and catheters, UPEC has evolved an intracellular pathogenic cascade that culminates in the formation of biofilm-like intracellular bacterial communities (IBCs) within bladder epithelial cells. Rapid bacterial replication during IBC formation augments a build-up in bacterial numbers and persistence within the host. Relatively little is known about factors mediating UPEC biofilm formation and how these overlap with IBC formation. To address this gap, we screened a UPEC transposon mutant library in three in vitro biofilm conditions: Luria broth (LB)-polyvinyl chloride (PVC), YESCA (yeast extract-Casamino Acids)-PVC, and YESCA-pellicle that are dependent on type 1 pili (LB) and curli (YESCA), respectively. Flagella are important in all three conditions. Mutants were identified that had biofilm defects in all three conditions but had no significant effects on the expression of type 1 pili, curli, or flagella. Thus, this approach uncovered a comprehensive inventory of novel effectors and regulators that are involved in UPEC biofilm formation under multiple conditions. A subset of these mutants was found to be dramatically attenuated and unable to form IBCs in a murine model of UTI. Collectively, this study expands our insights into UPEC multicellular behavior that may provide insights into IBC formation and virulence.

Hadjifrangiskou, Maria; Gu, Alice P.; Pinkner, Jerome S.; Kostakioti, Maria; Zhang, Ellisa W.; Greene, Sarah E.

2012-01-01

9

Forced Resurgence and Targeting of Intracellular Uropathogenic Escherichia coli Reservoirs  

PubMed Central

Intracellular quiescent reservoirs of uropathogenic Escherichia coli (UPEC), which can seed the bladder mucosa during the acute phase of a urinary tract infection (UTI), are protected from antibiotic treatments and are extremely difficult to eliminate. These reservoirs are a potential source for recurrent UTIs that affect millions annually. Here, using murine infection models and the bladder cell exfoliant chitosan, we demonstrate that intracellular UPEC populations shift within the stratified layers of the urothelium during the course of a UTI. Following invasion of the terminally differentiated superficial layer of epithelial cells that line the bladder lumen, UPEC can multiply and disseminate, eventually establishing reservoirs within underlying immature host cells. If given access, UPEC can invade the superficial and immature bladder cells equally well. As infected immature host cells differentiate and migrate towards the apical surface of the bladder, UPEC can reinitiate growth and discharge into the bladder lumen. By inducing the exfoliation of the superficial layers of the urothelium, chitosan stimulates rapid regenerative processes and the reactivation and efflux of quiescent intracellular UPEC reservoirs. When combined with antibiotics, chitosan treatment significantly reduces bacterial loads within the bladder and may therefore be of therapeutic value to individuals with chronic, recurrent UTIs.

Blango, Matthew G.; Ott, Elizabeth M.; Erman, Andreja; Veranic, Peter; Mulvey, Matthew A.

2014-01-01

10

Identification of uropathogenic Escherichia coli surface proteins by shotgun proteomics.  

PubMed

Uropathogenic Escherichia coli (UPEC) cause the majority of uncomplicated urinary tract infections in humans. In the process of identifying candidate antigens for a vaccine, two methods for the identification of the UPEC surface proteome during growth in human urine were investigated. The first approach utilized a protease to 'shave' surface-exposed peptides from the bacterial cell surface and identify them by mass spectrometry. Although this approach has been successfully applied to a Gram-positive pathogen, the adaptation to Gram-negative UPEC resulted in cytoplasmic protein contamination. In a more direct approach, whole-cell bacteria were labeled with a biotin tag to indicate surface-exposed peptides and two-dimensional liquid chromatography-tandem mass spectrometry (2-DLC-MS/MS) was used to identify proteins isolated from the outer membrane. This method discovered 25 predicted outer membrane proteins expressed by UPEC while growing in human urine. Nine of the 25 predicted outer membrane proteins were part of iron transport systems or putative iron-regulated virulence proteins, indicating the importance of iron acquisition during growth in urine. One of the iron transport proteins identified, Hma, appears to be a promising vaccine candidate is being further investigated. The method described here presents a system to rapidly identify the outer membrane proteome of bacteria, which may prove valuable in vaccine development. PMID:19426766

Walters, Matthew S; Mobley, Harry L T

2009-08-01

11

Invasive Disease Caused by Ciprofloxacin-Resistant Uropathogenic Escherichia coli  

Microsoft Academic Search

To evaluate the invasiveness of ciprofloxacin-resistant Escherichia coli isolated from the urinary tract, the susceptibility to ciprofloxacin of Escherichia coli strains from patients with invasive urinary tract infection was compared with that of isolates from patients with noninvasive\\u000a disease. In a 14-month period, 2054 different isolates of Escherichia coli were analyzed, of which 554 (27%) were resistant to ciprofloxacin. One

R. Blázquez; A. Menasalvas; I. Carpena; C. Ramírez; C. Guerrero; S. Moreno

1999-01-01

12

Integrated Genomic Map from Uropathogenic Escherichia coli J96  

PubMed Central

Escherichia coli J96 is a uropathogen having both broad similarities to and striking differences from nonpathogenic, laboratory E. coli K-12. Strain J96 contains three large (>100-kb) unique genomic segments integrated on the chromosome; two are recognized as pathogenicity islands containing urovirulence genes. Additionally, the strain possesses a fourth smaller accessory segment of 28 kb and two deletions relative to strain K-12. We report an integrated physical and genetic map of the 5,120-kb J96 genome. The chromosome contains 26 NotI, 13 BlnI, and 7 I-CeuI macrorestriction sites. Macrorestriction mapping was rapidly accomplished by a novel transposon-based procedure: analysis of modified minitransposon insertions served to align the overlapping macrorestriction fragments generated by three different enzymes (each sharing a common cleavage site within the insert), thus integrating the three different digestion patterns and ordering the fragments. The resulting map, generated from a total of 54 mini-Tn10 insertions, was supplemented with auxanography and Southern analysis to indicate the positions of insertionally disrupted aminosynthetic genes and cloned virulence genes, respectively. Thus, it contains not only physical, macrorestriction landmarks but also the loci for eight housekeeping genes shared with strain K-12 and eight acknowledged urovirulence genes; the latter confirmed clustering of virulence genes at the large unique accessory chromosomal segments. The 115-kb J96 plasmid was resolved by pulsed-field gel electrophoresis in NotI digests. However, because the plasmid lacks restriction sites for the enzymes BlnI and I-CeuI, it was visualized in BlnI and I-CeuI digests only of derivatives carrying plasmid inserts artificially introducing these sites. Owing to an I-SceI site on the transposon, the plasmid could also be visualized and sized from plasmid insertion mutants after digestion with this enzyme. The insertional strains generated in construction of the integrated genomic map provide useful physical and genetic markers for further characterization of the J96 genome.

Melkerson-Watson, Lyla J.; Rode, Christopher K.; Zhang, Lixin; Foxman, Betsy; Bloch, Craig A.

2000-01-01

13

Uropathogenic Escherichia coli Outer Membrane Antigens Expressed during Urinary Tract Infection  

Microsoft Academic Search

Received 2 March 2007\\/Returned for modification 13 April 2007\\/Accepted 14 May 2007 Uncomplicated urinary tract infection (UTI) caused by uropathogenic Escherichia coli (UPEC) represents a prevalent and potentially severe infectious disease. In this study, we describe the application of an immuno- proteomics approach to vaccine development that has been used successfully to identify vaccine targets in other pathogenic bacteria. Outer

Erin C. Hagan; Harry L. T. Mobley

2007-01-01

14

Identification of Type 3 Fimbriae in Uropathogenic Escherichia coli Reveals a Role in Biofilm Formation  

Microsoft Academic Search

Catheter-associated urinary tract infection (CAUTI) is the most common nosocomial infection in the United States. Uropathogenic Escherichia coli (UPEC), the most common cause of CAUTI, can form biofilms on indwelling catheters. Here, we identify and characterize novel factors that affect biofilm formation by UPEC strains that cause CAUTI. Sixty-five CAUTI UPEC isolates were characterized for phenotypic markers of urovirulence, including

Cheryl-Lynn Y. Ong; Glen C. Ulett; Amanda N. Mabbett; Scott A. Beatson; Richard I. Webb; Wayne Monaghan; Graeme R. Nimmo; David F. Looke; Alastair G. McEwan; Mark A. Schembri

2008-01-01

15

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

PubMed

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. PMID:18336383

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

16

Escherichia coli–Mediated Impairment of Ureteric Contractility Is Uropathogenic E. coli Specific  

PubMed Central

Background.?Ureters are fundamental for keeping kidneys free from uropathogenic Escherichia coli (UPEC), but we have shown that 2 strains (J96 and 536) can subvert this role and reduce ureteric contractility. To determine whether this is (1) a widespread feature of UPEC, (2) exhibited only by UPEC, and (3) dependent upon type 1 fimbriae, we analyzed strains representing epidemiologically important multilocus sequence types ST131, ST73, and ST95 and non-UPEC E. coli. Methods.?Contractility and calcium transients in intact rat ureters were compared between strains. Mannose and fim mutants were used to investigate the role of type 1 fimbriae. Results.?Non-UPEC had no significant effect on contractility, with a mean decrease after 8 hours of 8.8%, compared with 8.8% in controls. UPEC effects on contractility were strain specific, with decreases from 9.47% to 96.7%. Mannose inhibited the effects of the most potent strains (CFT073 and UTI89) but had variable effects among other UPEC strains. Mutation and complementation studies showed that the effects of the UTI89 cystitis isolate were fimH dependent. Conclusions.?We find that (1) non-UPEC do not affect ureteric contractility, (2) impairment of contractility is a common feature of UPEC, and (3) the mechanism varies between strains, but for the most potent UPEC type 1 fimbriae are involved.

Floyd, Rachel V.; Upton, Mathew; Hultgren, Scott J.; Wray, Susan; Burdyga, Theodor V.; Winstanley, Craig

2012-01-01

17

Extensive mosaic structure revealed by the complete genome sequence of uropathogenic Escherichia coli  

PubMed Central

We present the complete genome sequence of uropathogenic Escherichia coli, strain CFT073. A three-way genome comparison of the CFT073, enterohemorrhagic E. coli EDL933, and laboratory strain MG1655 reveals that, amazingly, only 39.2% of their combined (nonredundant) set of proteins actually are common to all three strains. The pathogen genomes are as different from each other as each pathogen is from the benign strain. The difference in disease potential between O157:H7 and CFT073 is reflected in the absence of genes for type III secretion system or phage- and plasmid-encoded toxins found in some classes of diarrheagenic E. coli. The CFT073 genome is particularly rich in genes that encode potential fimbrial adhesins, autotransporters, iron-sequestration systems, and phase-switch recombinases. Striking differences exist between the large pathogenicity islands of CFT073 and two other well-studied uropathogenic E. coli strains, J96 and 536. Comparisons indicate that extraintestinal pathogenic E. coli arose independently from multiple clonal lineages. The different E. coli pathotypes have maintained a remarkable synteny of common, vertically evolved genes, whereas many islands interrupting this common backbone have been acquired by different horizontal transfer events in each strain.

Welch, R. A.; Burland, V.; Plunkett, G.; Redford, P.; Roesch, P.; Rasko, D.; Buckles, E. L.; Liou, S.-R.; Boutin, A.; Hackett, J.; Stroud, D.; Mayhew, G. F.; Rose, D. J.; Zhou, S.; Schwartz, D. C.; Perna, N. T.; Mobley, H. L. T.; Donnenberg, M. S.; Blattner, F. R.

2002-01-01

18

Biofilm formation as a virulence determinant of uropathogenic Escherichia coli Dr+ strains.  

PubMed

Urinary tract infections are the most common health problem affecting millions of people each year. Uropathogenic Escherichia coli (UPEC) strains are the major factor causing lower and upper urinary tract infections. UPEC produce several virulence factors among which are surface exposed adhesive organelldes (pili/fimbriae) responsible for colonization, invasion and amplification within uroepithelial cells. The virulence of the uropathogenic E. coli Dr IH11128 is associated with Dr fimbriae belonging to the Dr family of adhesins (associated with diarrhea and urinary tract infections) and a DraD protein capping the linear fiber at the bacterial cell surface. In this study we revealed that biofilm development can be another urovirulence determinant allowing pathogenic E. coli Dr+ to survive within the urinary tract. E. coli strains were grown in rich or minimal media, allowed to adhere to abiotic surfaces and analyzed microscopically by staining of cells with cristal violet. We found that both Dr fimbriae and DraD, exposed at the cell surface in two forms, fimbria-associated or fimbria non-associated, (DraE+/DraD+, DraE+/DraD- or DraE-/DraD+ E. coli strains) are required for biofilm formation. Additionally, we demonstrated the biofilm formation capacity of E. coli strains deficient in the surface secretion or production of the DraE adhesin. PMID:19899615

Zalewska-Piatek, Beata M; Wilkanowicz, Sabina I; Piatek, Rafa? J; Kur, Józef W

2009-01-01

19

Quantitative Metabolomics Reveals an Epigenetic Blueprint for Iron Acquisition in Uropathogenic Escherichia coli  

PubMed Central

Bacterial pathogens are frequently distinguished by the presence of acquired genes associated with iron acquisition. The presence of specific siderophore receptor genes, however, does not reliably predict activity of the complex protein assemblies involved in synthesis and transport of these secondary metabolites. Here, we have developed a novel quantitative metabolomic approach based on stable isotope dilution to compare the complement of siderophores produced by Escherichia coli strains associated with intestinal colonization or urinary tract disease. Because uropathogenic E. coli are believed to reside in the gut microbiome prior to infection, we compared siderophore production between urinary and rectal isolates within individual patients with recurrent UTI. While all strains produced enterobactin, strong preferential expression of the siderophores yersiniabactin and salmochelin was observed among urinary strains. Conventional PCR genotyping of siderophore receptors was often insensitive to these differences. A linearized enterobactin siderophore was also identified as a product of strains with an active salmochelin gene cluster. These findings argue that qualitative and quantitative epi-genetic optimization occurs in the E. coli secondary metabolome among human uropathogens. Because the virulence-associated biosynthetic pathways are distinct from those associated with rectal colonization, these results suggest strategies for virulence-targeted therapies.

Henderson, Jeffrey P.; Crowley, Jan R.; Pinkner, Jerome S.; Walker, Jennifer N.; Tsukayama, Pablo; Stamm, Walter E.; Hooton, Thomas M.; Hultgren, Scott J.

2009-01-01

20

Inhibition of adhesion of uropathogenic Escherichia coli bacteria to uroepithelial cells by extracts from cranberry.  

PubMed

Cranberry extract has been reported as a therapeutic agent, mainly in urinary tract infections due to its anti-adhesive capacity. In order to compare the effects of proanthocyanidin (procyanidin) (PAC)-standardized cranberry extracts and commercial PAC A2, we first investigated the presence of genes encoding known adhesins on 13 strains of uropathogenic strains coming from patients with cystisis. After this characterization, the anti-adhesive effects of PAC A2 were assayed on selected uropathogenic Escherichia coli strains before testing cranberry extracts. Before checking inhibitory effect on bacterial adhesion to cells, we showed that neither PAC A2 or three cranberry extracts (A, B, and C) specifically inhibited the growth and did not supply any potential nutrient to E. coli strains, including the unrelated control strain. PAC A2 exhibited an inhibitory effect on the adhesion of two selected uropathogenic strains of E. coli. This work also showed that a preliminary exposure of bacteria to PAC A2 significantly reduced the adhesion. This phenomenon has been also observed with a lesser impact when uroepithelial cells were pretreated with PAC A2. Moreover, the assays were more robust when bacteria were in fast growing conditions (exponential phase): the adhesion to uroepithelial cells was greater. Significant reduction of adhesion to urepithelial cells was observed: around 80% of inhibition of adhesion with the cranberry extracts at equivalent PAC concentration of 50??g/mL. The effects of the different assayed extracts were not obviously different except for extract B, which inhibited approximately 55% of adhesion at an equivalent PAC concentration of 5??g/mL. PMID:22082066

Ermel, Gwennola; Georgeault, Sylvie; Inisan, Claude; Besnard, Matthieu

2012-02-01

21

Oral consumption of cranberry juice cocktail inhibits molecular-scale adhesion of clinical uropathogenic Escherichia coli.  

PubMed

Cranberry juice cocktail (CJC) has been shown to inhibit the formation of biofilm by uropathogenic Escherichia coli. In order to investigate whether the anti-adhesive components could reach the urinary tract after oral consumption of CJC, a volunteer was given 16?oz of either water or CJC. Urine samples were collected at 0, 2, 4, 6, and 8 hours after consumption of a single dose. The ability of compounds in the urine to influence bacterial adhesion was tested for six clinical uropathogenic E. coli strains, including four P-fimbriated strains (B37, CFT073, BF1023, and J96) and two strains not expressing P-fimbriae but exhibiting mannose-resistant hemagglutination (B73 and B78). A non-fimbriated strain, HB101, was used as a control. Atomic force microscopy (AFM) was used to measure the adhesion force between a silicon nitride probe and bacteria treated with urine samples. Within 2 hours after CJC consumption, bacteria of the clinical strains treated with the corresponding urine sample demonstrated lower adhesion forces than those treated with urine collected before CJC consumption. The adhesion forces continued decreasing with time after CJC consumption over the 8-hour measurement period. The adhesion forces of bacteria after exposure to urine collected following water consumption did not change. HB101 showed low adhesion forces following both water and CJC consumption, and these did not change over time. The AFM adhesion force measurements were consistent with the results of a hemagglutination assay, confirming that oral consumption of CJC could act against adhesion of uropathogenic E. coli. PMID:21480803

Tao, Yuanyuan; Pinzón-Arango, Paola A; Howell, Amy B; Camesano, Terri A

2011-01-01

22

Urine post equivalent daily cranberry juice consumption may opsonize uropathogenicity of Escherichia coli.  

PubMed

Basic studies have proven that cranberries may prevent urinary tract infections through changing the adhesiveness of Escherichia coli (E. coli) to urothelial cells. Various cranberry preparations, including extract powder, capsules, and juice, have been shown to be effective in clinical and epidemiological research. Because cranberries are most commonly consumed as juice in a diluted concentration, the aim of this study was to investigate whether the equivalent daily dose of cranberry juice is sufficient to modify host urine to change the uropathogenicity of E. coli. Urine from rats taking an equivalent daily dose of cranberry juice has been shown to decrease the capability of E. coli in hemagglutination, urothelium adhesion, nematode killing, and biofilm formation. All these changes occurred after E. coli was incubated in cranberry metabolite-containing urine, defined as urine opsonization. Urine opsonization of E. coli resulted in 40.9% (p = 0.0038) decrease in hemagglutination ability, 66.7% (p = 0.0181) decrease in urothelium adhesiveness, 16.7% (p = 0.0004) increase in the 50% lethal time in killing nematodes, and 53.9% (p = 5.9 × 10(-4)) decrease in biofilm formation. Thus, an equivalent daily dose of cranberry juice should be considered sufficiently potent to demonstrate urine opsonization in E. coli. PMID:23440506

Chen, Chih-Shou; Ho, Dong-Ru; Chang, Pey-Jium; Lin, Wei-Yu; Huang, Yun-Ching

2013-10-01

23

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

PubMed

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

Bien, Justyna; Sokolova, Olga; Bozko, Przemyslaw

2012-01-01

24

Diversity of gene cassette promoter variants of class 1 integrons in uropathogenic Escherichia coli.  

PubMed

Class 1 integrons play important roles in the emergence and horizontal transfer of antibiotic resistance genes among bacteria. The gene cassette promoter variants Pc or Pc-P2 of class 1 integrons not only drive the transcription of downstream gene cassettes, they also correlate with the excision and integration efficiency of the capture exogenous gene cassettes. In this study, the diversity of Pc or Pc-P2 variants of class 1 integrons and their association with antibiotic resistance phenotypes were analyzed in 132 uropathogenic Escherichia coli strains. Class 1 integrons were detected in 95 (72 %) strains. Sixteen different gene cassettes, 11 different gene cassette arrays and six different Pc or Pc-P2 variants were detected. The most prevalent gene cassettes were those that conferred resistance to trimethoprim, aminoglycosides, and chloramphenicol. The most prevalent promoter was PcH1, a relatively weak promoter. Certain gene cassette arrays or gene cassettes were mainly associated with the same Pc or Pc-P2 in different strains. Strains harboring class 1 integrons with relatively strong promoters had higher resistance rates to, or higher MIC(50) for, amikacin, chloramphenicol and tobramycin than those with relatively weak promoters. To the best of our knowledge, this is the first report of the diversity of class 1 integron Pc or Pc-P2 variants in uropathogenic E. coli strains. PMID:23743598

Wei, Quhao; Jiang, Xiaofei; Li, Min; Li, Gang; Hu, Qingfeng; Lu, Huoxiang; Chen, Guoqiang; Zhou, Yonglie; Lu, Yuan

2013-11-01

25

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

PubMed Central

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.

Bien, Justyna; Sokolova, Olga; Bozko, Przemyslaw

2012-01-01

26

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

PubMed Central

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).

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

1997-01-01

27

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

PubMed Central

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.

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

28

The RTX pore-forming toxin ?-hemolysin of uropathogenic Escherichia coli: progress and perspectives  

PubMed Central

Members of the RTX family of protein toxins are functionally conserved among an assortment of bacterial pathogens. By disrupting host cell integrity through their pore-forming and cytolytic activities, this class of toxins allows pathogens to effectively tamper with normal host cell processes, promoting pathogenesis. Here, we focus on the biology of RTX toxins by describing salient properties of a prototype member, ?-hemolysin, which is of ten encoded by strains of uropathogenic Escherichia coli. It has long been appreciated that RTX toxins can have distinct effects on host cells aside from outright lysis. Recently, advances in modeling and analysis of host–pathogen interactions have led to novel findings concerning the consequences of pore formation during host–pathogen interactions. We discuss current progress on longstanding questions concerning cell specificity and pore formation, new areas of investigation that involve toxin-mediated perturbations of host cell signaling cascades and perspectives on the future of RTX toxin investigation.

Wiles, Travis J; Mulvey, Matthew A

2013-01-01

29

Uropathogenic Escherichia coli virulence and innate immune responses during urinary tract infection.  

PubMed

Urinary tract infections (UTI) are among the most common infectious diseases of humans and are the most common nosocomial infections in the developed world. It is estimated that 40-50% of women and 5% of men will develop a UTI in their lifetime, and UTI accounts for more than 1 million hospitalizations and $1.6 billion in medical expenses each year in the USA. Uropathogenic Escherichia coli (UPEC) is the primary cause of UTI. This review presents an overview of recent discoveries related to the primary virulence factors of UPEC and major innate immune responses to infection of the lower urinary tract. New and emerging themes in UPEC research are discussed in the context of the interface between host and pathogen. PMID:23403118

Ulett, Glen C; Totsika, Makrina; Schaale, Kolja; Carey, Alison J; Sweet, Matthew J; Schembri, Mark A

2013-02-01

30

Implementation of Fourier transform infrared spectroscopy for the rapid typing of uropathogenic Escherichia coli.  

PubMed

In this paper, we demonstrate that Fourier transform infrared (FT-IR) spectroscopy is able to discriminate rapidly between uropathogenic Escherichia coli (UPEC) of key lineages with only relatively simple sample preparation. A total of 95 bacteria from six different epidemiologically important multilocus sequence types (ST10, ST69, ST95, ST73, ST127 and ST131) were used in this project and principal component-discriminant function analysis (PC-DFA) of these samples produced clear separate clustering of isolates, based on the ST. Analysis of data using partial least squares-discriminant analysis (PLS-DA), incorporating cross-validation, indicated a high prediction accuracy of 91.19% for ST131. These results suggest that FT-IR spectroscopy could be a useful method for the rapid identification of members of important UPEC STs. PMID:24399364

Dawson, S E; Gibreel, T; Nicolaou, N; AlRabiah, H; Xu, Y; Goodacre, R; Upton, M

2014-06-01

31

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

PubMed Central

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.

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

2013-01-01

32

Transcriptional responses of uropathogenic Escherichia coli to increased environmental osmolality caused by salt or urea.  

PubMed

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

Withman, Benjamin; Gunasekera, Thusitha S; Beesetty, Pavani; Agans, Richard; Paliy, Oleg

2013-01-01

33

Differentiation and developmental pathways of uropathogenic Escherichia coli in urinary tract pathogenesis  

PubMed Central

Uropathogenic Escherichia coli (UPEC) are capable of forming complex intracellular bacterial communities (IBC) within the superficial umbrella cells of the bladders of C3H and BALB/c mice. By using time-lapse fluorescence videomicroscopy to observe infected mouse bladder explants, we discovered that IBCs formed by uropathogenic E. coli progressed through four distinct developmental stages that differed with respect to growth rate, bacterial length, colony organization, motility, and its eventual dispersal. In the first phase, bacteria in the IBC were nonmotile, rod shaped, and grew rapidly in loosely organized colonies free in the cytoplasm of the bladder superficial umbrella cells. In the second phase, the loose collection of bacteria in the IBC matured into a slower growing, highly organized biofilm-like community consisting of coccoid bacteria that ultimately filled most of the cytoplasm. In the third phase, bacteria in the biofilm-like state in the IBC switched to a motile rod-shaped phenotype allowing detachment from the community and eventual fluxing out of the host cell. During the fourth phase, the bacteria filamented. Filamentation appeared to be in response to a Toll-like receptor 4-mediated innate defense mechanism. Bacteria that fluxed out of the superficial umbrella cells were able to reenter the IBC developmental cascade but with slower kinetics and ultimately a quiescent reservoir was established. Intracellular growth and filamentation provided an advantage to the bacteria in evading infiltrating polymorphonuclear leukocytes. This work has developed a technique to observe live infected organs and revealed a complex differentiation pathway that facilitates bacterial persistence in the urinary tract.

Justice, Sheryl S.; Hung, Chia; Theriot, Julie A.; Fletcher, Daniel A.; Anderson, Gregory G.; Footer, Matthew J.; Hultgren, Scott J.

2004-01-01

34

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

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

35

Medicinal plants extracts affect virulence factors expression and biofilm formation by the uropathogenic Escherichia coli.  

PubMed

Medicinal plants are an important source for the therapeutic remedies of various diseases including urinary tract infections. This prompted us to perform research in this area. We decided to focus on medicinal plants species used in urinary tract infections prevention. The aim of our study was to determine the influence of Betula pendula, Equisetum arvense, Herniaria glabra, Galium odoratum, Urtica dioica, and Vaccinium vitis-idaea extracts on bacterial survival and virulence factors involved in tissue colonization and biofilm formation of the uropathogenic Escherichia coli rods. Qualitative and quantitative analysis of plant extracts were performed. Antimicrobial assay relied on the estimation of the colony forming unit number. Hydrophobicity of cells was established by salt aggregation test. Using motility agar, the ability of bacteria to move was examined. The erythrocyte hemagglutination test was used for fimbriae P screening. Curli expression was determined using YESCA agar supplemented with congo red. Quantification of biofilm formation was carried out using a microtiter plate assay and a spectrophotometric method. The results of the study indicate significant differences between investigated extracts in their antimicrobial activities. The extracts of H. glabra and V. vitis-idaea showed the highest growth-inhibitory effects (p < 0.05). Surface hydrophobicity of autoaggregating E. coli strain changed after exposure to all plant extracts, except V. vitis-idaea (p > 0.05). The B. pendula and U. dioica extracts significantly reduced the motility of the E. coli rods (p < 0.05). All the extracts exhibited the anti-biofilm activity. PMID:22915095

Wojnicz, Dorota; Kucharska, Alicja Z; Sokó?-??towska, Anna; Kicia, Marta; Tichaczek-Goska, Dorota

2012-12-01

36

Genetics of digalactoside-binding adhesin from a uropathogenic Escherichia coli strain.  

PubMed Central

The uropathogenic strain Escherichia coli J96 mediates mannose-resistant hemagglutination owing to production of a digalactoside-binding adhesin. A cosmid clone from this strain has been isolated that, when harbored in E. coli K-12, expressed Pap pili and this adhesin (R. Hull et al., Infect. Immun. 33:933-938, 1981). By transposon mutagenesis and by the construction of a number of hybrid plasmid derivatives, we have demonstrated that about 8.5 kilobases of DNA is required to generate a mannose-resistant hemagglutination-positive phenotype in E. coli K-12 strain P678-54. The structural gene for the Pap pili monomer, papA, has been identified and mapped close to the promotor-proximal end of the Pap operon. Although strain P678-54 that harbored a Tn5 insertion within papA showed a mannose-resistant hemagglutination-positive phenotype, it was negative in a competitive enzyme-linked immunosorbent assay with anti-Pap pilus serum. This could mean that a Pap adhesin is encoded by a region on the Pap operon that is distinct from papA. Images

Normark, S; Lark, D; Hull, R; Norgren, M; Baga, M; O'Hanley, P; Schoolnik, G; Falkow, S

1983-01-01

37

Biofilm formation and virulence of uropathogenic Escherichia coli in urine after consumption of cranberry-lingonberry juice  

Microsoft Academic Search

Cranberry-lingonberry juice (CLJ) was effective in preventing urinary tract infections (UTIs) in our earlier randomized clinical\\u000a trial. We aimed to test whether consumption of CLJ at a similar dose to earlier reduces the biofilm formation and virulence\\u000a of uropathogenic Escherichia coli in urine. Twenty healthy women drank 100 ml of CLJ daily for two weeks. Urine samples were obtained 2–4 hours

T. Tapiainen; H. Jauhiainen; L. Jaakola; J. Salo; J. Sevander; I. Ikäheimo; A. M. Pirttilä; A. Hohtola; M. Uhari

38

The antibiotic susceptibility patterns of uropathogenic Escherichia coli, with special reference to the fluoroquinolones.  

PubMed

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 ?-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

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

2013-06-01

39

Identification of Type 3 Fimbriae in Uropathogenic Escherichia coli Reveals a Role in Biofilm Formation?  

PubMed Central

Catheter-associated urinary tract infection (CAUTI) is the most common nosocomial infection in the United States. Uropathogenic Escherichia coli (UPEC), the most common cause of CAUTI, can form biofilms on indwelling catheters. Here, we identify and characterize novel factors that affect biofilm formation by UPEC strains that cause CAUTI. Sixty-five CAUTI UPEC isolates were characterized for phenotypic markers of urovirulence, including agglutination and biofilm formation. One isolate, E. coli MS2027, was uniquely proficient at biofilm growth despite the absence of adhesins known to promote this phenotype. Mini-Tn5 mutagenesis of E. coli MS2027 identified several mutants with altered biofilm growth. Mutants containing insertions in genes involved in O antigen synthesis (rmlC and manB) and capsule synthesis (kpsM) possessed enhanced biofilm phenotypes. Three independent mutants deficient in biofilm growth contained an insertion in a gene locus homologous to the type 3 chaperone-usher class fimbrial genes of Klebsiella pneumoniae. These type 3 fimbrial genes (mrkABCDF), which were located on a conjugative plasmid, were cloned from E. coli MS2027 and could complement the biofilm-deficient transconjugants when reintroduced on a plasmid. Primers targeting the mrkB chaperone-encoding gene revealed its presence in CAUTI strains of Citrobacter koseri, Citrobacter freundii, Klebsiella pneumoniae, and Klebsiella oxytoca. All of these mrkB-positive strains caused type 3 fimbria-specific agglutination of tannic acid-treated red blood cells. This is the first description of type 3 fimbriae in E. coli, C. koseri, and C. freundii. Our data suggest that type 3 fimbriae may contribute to biofilm formation by different gram-negative nosocomial pathogens.

Ong, Cheryl-Lynn Y.; Ulett, Glen C.; Mabbett, Amanda N.; Beatson, Scott A.; Webb, Richard I.; Monaghan, Wayne; Nimmo, Graeme R.; Looke, David F.; McEwan, Alastair G.; Schembri, Mark A.

2008-01-01

40

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

PubMed

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. PMID:23462017

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

2013-03-01

41

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

PubMed

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. PMID:24096662

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

2013-01-01

42

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

PubMed

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. PMID:23710656

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

2013-08-01

43

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

PubMed Central

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.

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

2014-01-01

44

Pleiotropic roles of uvrY on biofilm formation, motility and virulence in uropathogenic Escherichia coli CFT073.  

PubMed

Urinary tract infections primarily caused by uropathogenic strains of Escherichia coli (E. coli) remain a significant public health problem in both developed and developing countries. An important virulence determinant in uropathogenesis is biofilm formation which requires expression of fimbriae, flagella, and other surface components such as lipopolysaccharides. In this study, we explored the regulation of uvrY and csrA genes in biofilm formation, motility and virulence determinants in uropathogenic E. coli. We found that mutation in uvrY suppressed biofilm formation on abiotic surfaces such as polyvinyl chloride, polystyrene and glass, and complementation of uvrY in the mutant restored the biofilm phenotype. We further evaluated the role of uvrY gene in expression of type 1 fimbriae, an important adhesin that facilitates adhesion to various abiotic surfaces. We found that phase variation of type 1 fimbriae between fimbriated and afimbriated mode was modulated by uvrY at its transcriptional level. Deletion mutant of uvrY lowered expression of fimbrial recombinase genes, such as fimB, fimE, and fimA, a gene encoding major fimbrial subunit. Furthermore, transcription of virulence specific genes such as papA, hlyB and galU was also reduced in the deletion mutant. Swarming motility and expression of flhD and flhC was also diminished in the mutant. Taken together, our findings unravel a possible mechanism in which uvrY facilitates biofilm formation, persistence and virulence of uropathogenic E. coli. PMID:23383333

Mitra, Arindam; Palaniyandi, Senthilkumar; Herren, Christopher D; Zhu, Xiaoping; Mukhopadhyay, Suman

2013-01-01

45

Pleiotropic Roles of uvrY on Biofilm Formation, Motility and Virulence in Uropathogenic Escherichia coli CFT073  

PubMed Central

Urinary tract infections primarily caused by uropathogenic strains of Escherichia coli (E. coli) remain a significant public health problem in both developed and developing countries. An important virulence determinant in uropathogenesis is biofilm formation which requires expression of fimbriae, flagella, and other surface components such as lipopolysaccharides. In this study, we explored the regulation of uvrY and csrA genes in biofilm formation, motility and virulence determinants in uropathogenic E. coli. We found that mutation in uvrY suppressed biofilm formation on abiotic surfaces such as polyvinyl chloride, polystyrene and glass, and complementation of uvrY in the mutant restored the biofilm phenotype. We further evaluated the role of uvrY gene in expression of type 1 fimbriae, an important adhesin that facilitates adhesion to various abiotic surfaces. We found that phase variation of type 1 fimbriae between fimbriated and afimbriated mode was modulated by uvrY at its transcriptional level. Deletion mutant of uvrY lowered expression of fimbrial recombinase genes, such as fimB, fimE, and fimA, a gene encoding major fimbrial subunit. Furthermore, transcription of virulence specific genes such as papA, hlyB and galU was also reduced in the deletion mutant. Swarming motility and expression of flhD and flhC was also diminished in the mutant. Taken together, our findings unravel a possible mechanism in which uvrY facilitates biofilm formation, persistence and virulence of uropathogenic E. coli.

Mitra, Arindam; Palaniyandi, Senthilkumar; Herren, Christopher D.; Zhu, Xiaoping; Mukhopadhyay, Suman

2013-01-01

46

YbcL of uropathogenic Escherichia coli suppresses transepithelial neutrophil migration.  

PubMed

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 ?ybcL) 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 ?ybcL 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 ?ybcL compared with wild-type UPEC. Our findings demonstrate a role for UPEC YbcL in suppression of the innate immune response during urinary tract infection. PMID:22966043

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

2012-12-01

47

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

PubMed

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 ?-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. PMID:23593422

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

2013-01-01

48

Persistence of uropathogenic Escherichia coli in the face of multiple antibiotics.  

PubMed

Numerous antibiotics have proven to be effective at ameliorating the clinical symptoms of urinary tract infections (UTIs), but recurrent and chronic infections continue to plague many individuals. Most UTIs are caused by strains of uropathogenic Escherichia coli (UPEC), which can form both extra- and intracellular biofilm-like communities within the bladder. UPEC also persist inside host urothelial cells in a more quiescent state, sequestered within late endosomal compartments. Here, we tested a panel of 17 different antibiotics, representing seven distinct functional classes, for their effects on the survival of the reference UPEC isolate UTI89 within both biofilms and host bladder urothelial cells. All but one of the tested antibiotics prevented UTI89 growth in broth culture, and most were at least modestly effective against bacteria present within in vitro-grown biofilms. In contrast, only a few of the antibiotics, including nitrofurantoin and the fluoroquinolones ciprofloxacin and sparfloxacin, were able to eliminate intracellular bacteria in bladder cell culture-based assays. However, in a mouse UTI model system in which these antibiotics reached concentrations in the urine specimens that far exceeded minimal inhibitory doses, UPEC reservoirs in bladder tissues were not effectively eradicated. We conclude that the persistence of UPEC within the bladder, regardless of antibiotic treatments, is likely facilitated by a combination of biofilm formation, entry of UPEC into a quiescent or semiquiescent state within host cells, and the stalwart permeability barrier function associated with the bladder urothelium. PMID:20231390

Blango, Matthew G; Mulvey, Matthew A

2010-05-01

49

Characterization of a dipartite iron uptake system from uropathogenic Escherichia coli strain F11.  

PubMed

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 His(44), Met(90), His(97), and His(127), and CuB, a second degenerate octahedral geometry with the addition of Glu(46). The copper ions of each site occupy distinct positions and are separated by ?1.3 ?. 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

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

2011-07-15

50

Role of capsule and O antigen in the virulence of uropathogenic Escherichia coli.  

PubMed

Urinary tract infection (UTI) is one of the most common bacterial infections in humans, with uropathogenic Escherichia coli (UPEC) the leading causative organism. UPEC has a number of virulence factors that enable it to overcome host defenses within the urinary tract and establish infection. The O antigen and the capsular polysaccharide are two such factors that provide a survival advantage to UPEC. Here we describe the application of the rpsL counter selection system to construct capsule (kpsD) and O antigen (waaL) mutants and complemented derivatives of three reference UPEC strains: CFT073 (O6:K2:H1), RS218 (O18:K1:H7) and 1177 (O1:K1:H7). We observed that while the O1, O6 and O18 antigens were required for survival in human serum, the role of the capsule was less clear and linked to O antigen type. In contrast, both the K1 and K2 capsular antigens provided a survival advantage to UPEC in whole blood. In the mouse urinary tract, mutation of the O6 antigen significantly attenuated CFT073 bladder colonization. Overall, this study contrasts the role of capsule and O antigen in three common UPEC serotypes using defined mutant and complemented strains. The combined mutagenesis-complementation strategy can be applied to study other virulence factors with complex functions both in vitro and in vivo. PMID:24722484

Sarkar, Sohinee; Ulett, Glen C; Totsika, Makrina; Phan, Minh-Duy; Schembri, Mark A

2014-01-01

51

Estrogenic modulation of uropathogenic Escherichia coli infection pathogenesis in a murine menopause model.  

PubMed

Recurrent urinary tract infections (UTIs), primarily caused by uropathogenic Escherichia coli (UPEC), annually affect over 13 million patients in the United States. Menopausal women are disproportionally susceptible, suggesting estrogen deficiency is a significant risk factor for chronic and recurrent UTI. How estrogen status governs susceptibility to UTIs remains unknown, and whether hormone therapy protects against UTIs remains controversial. Here, we used a mouse model of surgical menopause by ovariectomy and demonstrate a protective role for estrogen in UTI pathogenesis. We found that ovariectomized mice had significantly higher bacteriuria, a more robust inflammatory response, and increased production of the proinflammatory cytokine interleukin-6 (IL-6) upon UPEC infection compared to sham-operated controls. We further show that response of the urothelial stem cell niche to infection, normally activated to restore homeostasis after infection, was aberrant in ovariectomized mice with defective superficial urothelial cell differentiation. Finally, UPEC-infected ovariectomized mice showed a significant increase in quiescent intracellular bacterial reservoirs, which reside in the urothelium and can seed recurrent infections. Importantly, this and other ovariectomy-induced outcomes of UTI were reversible upon estrogen supplementation. Together, our findings establish ovariectomized mice as a model for UTIs in menopausal women and pinpoint specific events during course of infection that are most susceptible to estrogen deficiency. These findings have profound implications for the understanding of the role of estrogen and estrogen therapy in bladder health and pathogen defense mechanisms and open the door for prophylaxis for menopausal women with recurrent UTIs. PMID:23264047

Wang, Caihong; Symington, Jane W; Ma, Emily; Cao, Bin; Mysorekar, Indira U

2013-03-01

52

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

PubMed

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-?B 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. PMID:23990566

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

2014-02-01

53

Estrogenic Modulation of Uropathogenic Escherichia coli Infection Pathogenesis in a Murine Menopause Model  

PubMed Central

Recurrent urinary tract infections (UTIs), primarily caused by uropathogenic Escherichia coli (UPEC), annually affect over 13 million patients in the United States. Menopausal women are disproportionally susceptible, suggesting estrogen deficiency is a significant risk factor for chronic and recurrent UTI. How estrogen status governs susceptibility to UTIs remains unknown, and whether hormone therapy protects against UTIs remains controversial. Here, we used a mouse model of surgical menopause by ovariectomy and demonstrate a protective role for estrogen in UTI pathogenesis. We found that ovariectomized mice had significantly higher bacteriuria, a more robust inflammatory response, and increased production of the proinflammatory cytokine interleukin-6 (IL-6) upon UPEC infection compared to sham-operated controls. We further show that response of the urothelial stem cell niche to infection, normally activated to restore homeostasis after infection, was aberrant in ovariectomized mice with defective superficial urothelial cell differentiation. Finally, UPEC-infected ovariectomized mice showed a significant increase in quiescent intracellular bacterial reservoirs, which reside in the urothelium and can seed recurrent infections. Importantly, this and other ovariectomy-induced outcomes of UTI were reversible upon estrogen supplementation. Together, our findings establish ovariectomized mice as a model for UTIs in menopausal women and pinpoint specific events during course of infection that are most susceptible to estrogen deficiency. These findings have profound implications for the understanding of the role of estrogen and estrogen therapy in bladder health and pathogen defense mechanisms and open the door for prophylaxis for menopausal women with recurrent UTIs.

Wang, Caihong; Symington, Jane W.; Ma, Emily; Cao, Bin

2013-01-01

54

High Metabolic Potential May Contribute to the Success of ST131 Uropathogenic Escherichia coli  

PubMed Central

Uropathogenic Escherichia coli (UPEC) is the predominant cause of urinary tract infection in both hospital and community settings. The recent emergence of multidrug-resistant clones like the O25b:H4-ST131 lineage represents a significant threat to health, and numerous studies have explored the virulence potential of these organisms. Members of the ST131 clone have been described as having variable carriage of key virulence factors, and it has been suggested that additional unidentified factors contribute to virulence. Here we demonstrated that ST131 isolates have high metabolic potential and biochemical profiles that distinguish them from isolates of many other sequence types (STs). A collection of 300 UPEC isolates recovered in 2007 and 2009 in the Northwest region of England were subjected to metabolic profiling using the Vitek2 Advanced Expert System (AES). Of the 47 tests carried out, 30 gave a positive result with at least one of the 300 isolates examined. ST131 isolates demonstrated significant association with eight tests, including those for peptidase, decarboxylase, and alkalinization activity. Metabolic activity also correlated with antibiotic susceptibility profiles, with resistant organisms displaying the highest metabolic potential. This is the first comprehensive study of metabolic potential in the ST131 lineage, and we suggest that high metabolic potential may have contributed to the fitness of members of the ST131 clone, which are able to exploit the available nutrients in both the intestinal and urinary tract environments.

Gibreel, Tarek M.; Dodgson, Andrew R.; Cheesbrough, John; Bolton, Frederick J.; Fox, Andrew J.

2012-01-01

55

Waging War against Uropathogenic Escherichia coli: Winning Back the Urinary Tract?  

PubMed Central

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.

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

2010-01-01

56

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

PubMed Central

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 ?. 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.

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

2011-01-01

57

Transcriptional activation of a pap pilus virulence operon from uropathogenic Escherichia coli.  

PubMed Central

A gene cluster mediating production of pili in uropathogenic Escherichia coli was analysed with respect to regulation of pili synthesis. Two cistrons, papB and papI, were localized upstream of the major pilus subunit gene, papA. The papI-papB-papA region was characterized by nucleotide sequencing and by transcriptional analysis. The papA gene was primarily represented by an 800 nucleotide long transcript but was also co-transcribed with papB as a less abundant 1300 nucleotide long mRNA. Both transcripts presumably terminated at the same site downstream of the papA coding sequence. The weakly expressed papI gene was transcribed in the opposite direction to that of papB and papA. Studies with lacZ operon fusions showed that the papB gene encoded a trans-active effector required for papA transcription. Similarly, the papI gene stimulated papB transcription in trans. Furthermore, full expression of papA was cis dependent upon the papI-papB region. Transcription of the papB gene was shown to be dependent upon cAMP and its receptor protein. A binding site for the cAMP-CRP complex was postulated in the DNA sequence upstream of the papB promoter. Images Fig. 3.

Baga, M; Goransson, M; Normark, S; Uhlin, B E

1985-01-01

58

The Cpx stress response system potentiates the fitness and virulence of uropathogenic Escherichia coli.  

PubMed

Strains of uropathogenic Escherichia coli (UPEC) are the primary cause of urinary tract infections, representing one of the most widespread and successful groups of pathogens on the planet. To colonize and persist within the urinary tract, UPEC must be able to sense and respond appropriately to environmental stresses, many of which can compromise the bacterial envelope. The Cpx two-component envelope stress response system is comprised of the inner membrane histidine kinase CpxA, the cytosolic response regulator CpxR, and the periplasmic auxiliary factor CpxP. Here, by using deletion mutants along with mouse and zebrafish infection models, we show that the Cpx system is critical to the fitness and virulence of two reference UPEC strains, the cystitis isolate UTI89 and the urosepsis isolate CFT073. Specifically, deletion of the cpxRA operon impaired the ability of UTI89 to colonize the murine bladder and greatly reduced the virulence of CFT073 during both systemic and localized infections within zebrafish embryos. These defects coincided with diminished host cell invasion by UTI89 and increased sensitivity of both strains to complement-mediated killing and the aminoglycoside antibiotic amikacin. Results obtained with the cpxP deletion mutants were more complicated, indicating variable strain-dependent and niche-specific requirements for this well-conserved auxiliary factor. PMID:23429541

Debnath, Irina; Norton, J Paul; Barber, Amelia E; Ott, Elizabeth M; Dhakal, Bijaya K; Kulesus, Richard R; Mulvey, Matthew A

2013-05-01

59

Uropathogenic Escherichia coli Triggers Oxygen-Dependent Apoptosis in Human Neutrophils through the Cooperative Effect of Type 1 Fimbriae and Lipopolysaccharide  

Microsoft Academic Search

Type 1 fimbriae are the most commonly expressed virulence factor on uropathogenic Escherichia coli .I n addition to promoting avid bacterial adherence to the uroepithelium and enabling colonization, type 1 fimbriae recruit neutrophils to the urinary tract as an early inflammatory response. Using clinical isolates of type 1 fimbriated E. coli and an isogenic type 1 fimbria-negative mutant (CN1016) lacking

Robert Blomgran; Limin Zheng; Olle Stendahl

2004-01-01

60

Suppression of type 1 pilus assembly in uropathogenic Escherichia coli by chemical inhibition of subunit polymerization  

PubMed Central

Objectives To identify and to characterize small-molecule inhibitors that target the subunit polymerization of the type 1 pilus assembly in uropathogenic Escherichia coli (UPEC). Methods Using an SDS–PAGE-based assay, in silico pre-filtered small-molecule compounds were screened for specific inhibitory activity against the critical subunit polymerization step of the chaperone–usher pathway during pilus biogenesis. The biological activity of one of the compounds was validated in assays monitoring UPEC type 1 pilus biogenesis, type 1 pilus-dependent biofilm formation and adherence to human bladder epithelial cells. The time dependence of the in vivo inhibitory activity and the overall effect of the compound on UPEC growth were determined. Results N-(4-chloro-phenyl)-2-{5-[4-(pyrrolidine-1-sulfonyl)-phenyl]-[1,3,4]oxadiazol-2-yl sulfanyl}-acetamide (AL1) inhibited in vitro pilus subunit polymerization. In bacterial cultures, AL1 disrupted UPEC type 1 pilus biogenesis and pilus-dependent biofilm formation, and resulted in the reduction of bacterial adherence to human bladder epithelial cells, without affecting bacterial cell growth. Bacterial exposure to the inhibitor led to an almost instantaneous loss of type 1 pili. Conclusions We have identified and characterized a small molecule that interferes with the assembly of type 1 pili. The molecule targets the polymerization step during the subunit incorporation cycle of the chaperone–usher pathway. Our discovery provides new insight into the design and development of novel anti-virulence therapies targeting key virulence factors of bacterial pathogens.

Lo, Alvin W. H.; Van de Water, Karen; Gane, Paul J.; Chan, A.W. Edith; Steadman, David; Stevens, Kiri; Selwood, David L.; Waksman, Gabriel; Remaut, Han

2014-01-01

61

Genome-wide detection of fitness genes in uropathogenic Escherichia coli during systemic infection.  

PubMed

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

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

2013-01-01

62

Functional Heterogeneity of the UpaH Autotransporter Protein from Uropathogenic Escherichia coli  

PubMed Central

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.

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

2012-01-01

63

Renal abscess yields elusive hypermucoviscous phenotype of, uropathogenic Escherichia coli: a case report.  

PubMed

Uropathogenic E. coli (UPEC) strains are described as extraintestinal pathogenic E. coli with preference for the urinary tract. Bottone et al2 recently described the first documentation of a hypermucoviscous phenotype of a UPEC strain that displays a "stringing" phenomenon analogous to those produced by Klebsiella pneumonia strains known to invade the liver. The occurrence of this hypermucoviscous phenotype of UPEC strains causing urinary tract infection has not been well established. Following, we present a case report of two separate renal isolates from a patient with recurrent renal abscesses yielding the aforementioned hypermucoviscous phenotype of UPEC strains. PMID:24596985

Benham, Aaron; Davis, Jeffrey; Puzio, Corinne; Blakey, Gregory; Slobodov, Gennady

2013-11-01

64

Molecular Characterization of Uropathogenic Escherichia coli: Nalidixic Acid and Ciprofloxacin Resistance, Virulent Factors and Phylogenetic Background.  

PubMed

Background and Objective: A proficient pathogen should be virulent, resistant to antibiotics, and epidemic. However, the interplay between resistance and virulence is poorly understood. Perhaps, the most commonly accepted view is that resistance to quinolones is linked to a loss of virulence factors. However, the low virulent phylogenetic groups may be more prone to acquire resistance to quinolones. The aim of this study was to identify and characterise the Nalidixic Acid (NA) and ciprofloxacin (CIP) resistant uropathogenic Escherichia coli (UPEC) isolates with respect to virulence and phylogenetic background, from hospital settings in Kolkata, an eastern region in India. Research based on these bacterial populations will help in understanding the molecular mechanisms underlying the association between resistance and virulence, that in turn, may help in managing the future disseminations of UTIs in their entirety. Material and Methods: One hundred and ten E. coli isolates were screened against NA and CIP using Kirby-Bauer disk diffusion technique, following CLSI guidelines. Prevalence of virulent factor genes and distribution of phylogenetic groups amongst the isolates was determined by PCR, using gene specific primers against the different virulent factors and DNA markers (chuA, yjaA and DNA fragment, TSPE4.C2) respectively. Statistical analysis of the data was performed using SPSS software. Results: Resistance to both NA and CIP was reported in 75.5 % of the isolates which were analysed. The virulent determinants, papC, pap GII, papEF, afa, cnf1, hlyA and iroN were significantly predominant in the drug susceptible than the resistant isolates. A significant reduction of phylogroup B2 in NA (85.7% versus 64.6%, ?(2)P<0.001) and CIP (85.2 % versus 61.4%, ?(2)P<0.001) resistant UPEC isolates, followed by increase in predominance of non-B2 phylotypes (group D and group B1), were observed. Conclusion: This is the first report from India that has indicated possible evidence on horizontal gene transfer from pathogenic to commensal strains and selection of the latter, on extensive usage of this group of antimicrobials in hospital settings, where these drugs were routinely prescribed for treating urinary tract infection. Therefore, this information necessitates surveillance programs and administration of effective strategies, to put an end to random prescription policies involving this group of antimicrobials. PMID:24551624

Basu, Shreya; Mukherjee, Sandip Kumar; Hazra, Avijit; Mukherjee, Mandira

2013-12-01

65

Induction of a state of iron limitation in uropathogenic Escherichia coli CFT073 by cranberry-derived proanthocyanidins as revealed by microarray analysis.  

PubMed

Transcriptional profiles of uropathogenic Escherichia coli CFT073 exposed to cranberry-derived proanthocyanidins (PACs) were determined. Our results indicate that bacteria grown on media supplemented with PACs were iron deprived. To our knowledge, this is the first time that PACs have been shown to induce a state of iron limitation in this bacterium. PMID:21169441

Hidalgo, Gabriela; Ponton, André; Fatisson, Julien; O'May, Che; Asadishad, Bahareh; Schinner, Tim; Tufenkji, Nathalie

2011-02-01

66

Uropathogenic Escherichia coli causes cortical tubular necrotic cell death and the release of macrophage migration inhibitory factor.  

PubMed

The macrophage migration inhibitory factor (MIF), a pro-inflammatory cytokine, is deregulated in acute kidney injury (AKI) through an unknown mechanism. In the present study, we used a previously described mouse model of ascending urinary tract infection in which uropathogenic Escherichia coli (UPEC) were transurethrally inoculated to induce kidney infections. Here, we show that urinary MIF was upregulated during AKI while MIF was abundantly expressed in the renal cortical tubules and that UPEC infection caused a decrease in tubular MIF. Infections with UPEC in vitro caused MIF release in a cell type-dependent manner, which was independent of receptor-mediated internalization, signal transduction, and transcription. Indeed, UPEC infection-induced necrotic cell death in vitro and in vivo correlated with extracellular acidification and processed MIF secretion. These data suggest that MIF is released by necrotic renal cortical tubular cells during UPEC infection. PMID:23410506

Hong, Ming-Yuan; Tseng, Chin-Chung; Chuang, Chia-Chang; Chen, Chia-Ling; Lin, Yu-Huei; Hsieh, Chia-Yuan; Chang, Yu-Tzu; Hsing, Chung-Hsi; Chang, Kwang-Yu; Lin, Chiou-Feng

2013-03-01

67

Combinatorial Small-Molecule Therapy Prevents Uropathogenic Escherichia coli Catheter-Associated Urinary Tract Infections in Mice  

PubMed Central

Catheter-associated urinary tract infections (CAUTIs) constitute the majority of nosocomial urinary tract infections (UTIs) and pose significant clinical challenges. These infections are polymicrobial in nature and are often associated with multidrug-resistant pathogens, including uropathogenic Escherichia coli (UPEC). Urinary catheterization elicits major histological and immunological alterations in the bladder that can favor microbial colonization and dissemination in the urinary tract. We report that these biological perturbations impact UPEC pathogenesis and that bacterial reservoirs established during a previous UPEC infection, in which bacteriuria had resolved, can serve as a nidus for subsequent urinary catheter colonization. Mannosides, small molecule inhibitors of the type 1 pilus adhesin, FimH, provided significant protection against UPEC CAUTI by preventing bacterial invasion and shifting the UPEC niche primarily to the extracellular milieu and on the foreign body. By doing so, mannosides potentiated the action of trimethoprim-sulfamethoxazole in the prevention and treatment of CAUTI. In this study, we provide novel insights into UPEC pathogenesis in the context of urinary catheterization, and demonstrate the efficacy of novel therapies that target critical mechanisms for this infection. Thus, we establish a proof-of-principle for the development of mannosides to prevent and eventually treat these infections in the face of rising antibiotic-resistant uropathogens.

Guiton, Pascale S.; Cusumano, Corinne K.; Kline, Kimberly A.; Dodson, Karen W.; Han, Zhenfu; Janetka, James W.; Henderson, Jeffrey P.; Caparon, Michael G.

2012-01-01

68

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

PubMed

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

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

2013-01-01

69

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

PubMed Central

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.

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

2013-01-01

70

Biofilm formation and virulence of uropathogenic Escherichia coli in urine after consumption of cranberry-lingonberry juice.  

PubMed

Cranberry-lingonberry juice (CLJ) was effective in preventing urinary tract infections (UTIs) in our earlier randomized clinical trial. We aimed to test whether consumption of CLJ at a similar dose to earlier reduces the biofilm formation and virulence of uropathogenic Escherichia coli in urine. Twenty healthy women drank 100 ml of CLJ daily for two weeks. Urine samples were obtained 2-4 hours after the last dose. Control samples were taken after a one-week period without berry consumption. Biofilm formation of 20 E. coli strains was measured at 72 hours by the polystyrene microtitre plate method. Quantitative real-time PCR analyses were performed for selected genes. Four of the 20 clinical strains produced more biofilm in urine after CLJ consumption (P < 0.05) and one produced less. Expression levels of the pga, cpxA, fimA and papF genes did not differ between bacteria grown in control urine and urine obtained after CLJ consumption, except for pga gene expression, which was reduced in one strain after CLJ (P = 0.04). It appears that the effect of CLJ in preventing UTIs is not explained by mechanisms that reduce biofilm formation or the expression of selected virulence genes of Escherichia coli in urine. PMID:21822564

Tapiainen, T; Jauhiainen, H; Jaakola, L; Salo, J; Sevander, J; Ikäheimo, I; Pirttilä, A M; Hohtola, A; Uhari, M

2012-05-01

71

UpaG, a New Member of the Trimeric Autotransporter Family of Adhesins in Uropathogenic Escherichia coli? †  

PubMed Central

The ability of Escherichia coli to colonize both intestinal and extraintestinal sites is driven by the presence of specific virulence factors, among which are the autotransporter (AT) proteins. Members of the trimeric AT adhesin family are important virulence factors for several gram-negative pathogens and mediate adherence to eukaryotic cells and extracellular matrix (ECM) proteins. In this study, we characterized a new trimeric AT adhesin (UpaG) from uropathogenic E. coli (UPEC). Molecular analysis of UpaG revealed that it is translocated to the cell surface and adopts a multimeric conformation. We demonstrated that UpaG is able to promote cell aggregation and biofilm formation on abiotic surfaces in CFT073 and various UPEC strains. In addition, UpaG expression resulted in the adhesion of CFT073 to human bladder epithelial cells, with specific affinity to fibronectin and laminin. Prevalence analysis revealed that upaG is strongly associated with E. coli strains from the B2 and D phylogenetic groups, while deletion of upaG had no significant effect on the ability of CFT073 to colonize the mouse urinary tract. Thus, UpaG is a novel trimeric AT adhesin from E. coli that mediates aggregation, biofilm formation, and adhesion to various ECM proteins.

Valle, Jaione; Mabbett, Amanda N.; Ulett, Glen C.; Toledo-Arana, Alejandro; Wecker, Karine; Totsika, Makrina; Schembri, Mark A.; Ghigo, Jean-Marc; Beloin, Christophe

2008-01-01

72

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. ...

73

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

NASA Astrophysics Data System (ADS)

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.

Samoilov, Michael

2010-03-01

74

Nutritional requirements for growth of uropathogenic Escherichia coli in human urine.  

PubMed

Enrichment with D-cycloserine was used to identify Escherichia coli auxotrophic mutants that exhibited limited growth in human urine. Bacterial synthesis of guanine, arginine, and glutamine was found to be required for optimal growth in urine. Mutants that required leucine, methionine, serine, phenylalanine, or proline also exhibited reduced growth in urine. Several other nutritional mutants, including nicotinamide auxotrophs, which are found frequently among cystitis isolates, exhibited normal growth in urine. PMID:9125589

Hull, R A; Hull, S I

1997-05-01

75

Intramacrophage survival of uropathogenic Escherichia coli: Differences between diverse clinical isolates and between mouse and human macrophages  

Microsoft Academic Search

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

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

2011-01-01

76

Oxygen-Limiting Conditions Enrich for Fimbriate Cells of Uropathogenic Proteus mirabilis and Escherichia coli  

Microsoft Academic Search

MR\\/P fimbriae of uropathogenic Proteus mirabilis undergo invertible element-mediated phase variation whereby an individual bacterium switches between expressing fimbriae (phase ON) and not expressing fimbriae (phase OFF). Under different conditions, the percentage of fimbriate bacteria within a population varies and could be dictated by either selection (growth advantage of one phase) or signaling (preferentially converting one phase to the other

Xin Li; Melanie M. Pearson; Amy N. Simms; Harry L. T. Mobley

2009-01-01

77

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

PubMed

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: ?-ketoglutarate utilization sensor; KguR: ?-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 ?-ketoglutarate (?-KG). These genes were further shown to be involved in utilization of ?-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 ?-ketoglutarate in vivo thereby facilitating UPEC adaptation to life inside the urinary tract. PMID:23825943

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

78

The Repeat-In-Toxin Family Member TosA Mediates Adherence of Uropathogenic Escherichia coli and Survival during Bacteremia  

PubMed Central

Uropathogenic Escherichia coli (UPEC) is responsible for the majority of uncomplicated urinary tract infections (UTI) and represents the most common bacterial infection in adults. UPEC utilizes a wide range of virulence factors to colonize the host, including the novel repeat-in-toxin (RTX) protein TosA, which is specifically expressed in the host urinary tract and contributes significantly to the virulence and survival of UPEC. tosA, found in strains within the B2 phylogenetic subgroup of E. coli, serves as a marker for strains that also contain a large number of well-characterized UPEC virulence factors. The presence of tosA in an E. coli isolate predicts successful colonization of the murine model of ascending UTI, regardless of the source of the isolate. Here, a detailed analysis of the function of tosA revealed that this gene is transcriptionally linked to genes encoding a conserved type 1 secretion system similar to other RTX family members. TosA localized to the cell surface and was found to mediate (i) adherence to host cells derived from the upper urinary tract and (ii) survival in disseminated infections and (iii) to enhance lethality during sepsis (as assessed in two different animal models of infection). An experimental vaccine, using purified TosA, protected vaccinated animals against urosepsis. From this work, it was concluded that TosA belongs to a novel group of RTX proteins that mediate adherence and host damage during UTI and urosepsis and could be a novel target for the development of therapeutics to treat ascending UTIs.

Vigil, Patrick D.; Wiles, Travis J.; Engstrom, Michael D.; Prasov, Lev; Mulvey, Matthew A.

2012-01-01

79

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

PubMed Central

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.

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

2012-01-01

80

P-antigen-recognizing fimbriae from human uropathogenic Escherichia coli strains.  

PubMed Central

P-antigen-recognizing fimbriae (P fimbriae) from four pyelonephritogenic Escherichia coli strains and type 1 fimbriae from an E. coli strain and a Salmonella typhimurium strain were purified. The P fimbriae were morphologically similar to type 1 fimbriae. The purified P fimbriae agglutinated neuraminidase-treated human P1 and P2k erythrocytes but not p erythrocytes, which lack all P-blood group-specific glycosphingolipids. However, coating of neuraminidase-treated p erythrocytes with globoside rendered such erythrocytes agglutinable by the P fimbriae. The hemagglutinations were in all instances fully inhibited by the synthetic alpha-D-Galp-(1-4)-beta-D-Galp-1-O-Me glycoside. The binding specificity of the P fimbriae could also be demonstrated by using fimbriae coated onto latex particles and nontreated erythrocytes. It was thus concluded that the P fimbriae recognize and bind to the alpha-D-Galp-(1-4)-beta-D-Galp carbohydrate sequence occurring in the series of P-blood group antigen-specific glycosphingolipids. In contrast to both type 1 fimbriae, all four P fimbriae preparations showed multiple bands in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Antisera were raised in rabbits against the various E. coli fimbriae. In enzyme-linked immunosorbent assays each one of the antisera to the P fimbriae reacted to titers of log 4 to 7 with both the homologous and the heterologous P fimbriae, but not with the type 1 fimbriae of E. coli. In a reciprocal fashion, the antiserum to the type 1 fimbriae of one E. coli strain reacted only with the homologous type 1 but not with any of the P fimbriae preparations. Images

Korhonen, T K; Vaisanen, V; Saxen, H; Hultberg, H; Svenson, S B

1982-01-01

81

Decreased Expression of Type 1 Fimbriae by a pst Mutant of Uropathogenic Escherichia coli Reduces Urinary Tract Infection  

PubMed Central

The pstSCAB-phoU operon encodes the phosphate-specific transport system (Pst). Loss of Pst constitutively activates the Pho regulon and decreases bacterial virulence. However, specific mechanisms underlying decreased bacterial virulence through inactivation of Pst are poorly understood. In uropathogenic Escherichia coli (UPEC) strain CFT073, inactivation of pst decreased urinary tract colonization in CBA/J mice. The pst mutant was deficient in production of type 1 fimbriae and showed decreased expression of the fimA structural gene which correlated with differential expression of the fimB, fimE, ipuA, and ipbA genes, encoding recombinases, mediating inversion of the fim promoter. The role of fim downregulation in attenuation of the pst mutant was confirmed using a fim phase-locked-on derivative, which demonstrated a significant gain in virulence. In addition, the pst mutant was less able to invade human bladder epithelial cells. Since type 1 fimbriae contribute to UPEC virulence by promoting colonization and invasion of bladder cells, the reduced bladder colonization by the pst mutant is predominantly attributed to downregulation of these fimbriae. Elucidation of mechanisms mediating the control of type 1 fimbriae through activation of the Pho regulon in UPEC may open new avenues for therapeutics or prophylactics against urinary tract infections.

Crepin, Sebastien; Houle, Sebastien; Charbonneau, Marie-Eve; Mourez, Michael; Harel, Josee

2012-01-01

82

Assessment of immune responses of the flagellin (FliC) fused to FimH adhesin of Uropathogenic Escherichia coli.  

PubMed

Urinary tract infection (UTI) caused by Uropathogenic Escherichia coli (UPEC) is one of the most common infectious diseases in the world. Despite extensive efforts, a vaccine that protects humans against UTI is currently missing. In this study, the immunogenicity of flagellin (FliC) of UPEC strain in different vaccine combinations with FimH antigen of UPEC and conventional adjuvant Montanide ISA 206 was assessed. Finally, efficacy of the immune responses was evaluated for protection of the bladder and kidney of challenged immunized mice. Mice immunized with the fusion FimH·FliC induced significantly higher anti-FliC humoral (IgG1) and cellular (Th1 and Th2) immune responses than with FliC alone or FliC admixed with FimH. The Montanide enhanced the immune responses of FliC antigen and directed the anti-FliC responses preferentially toward Th1. The FliC vaccine combinations reduced bladder infection as compared to control mice. The fusion FimH·FliC and FliC admixed with FimH and Montanide combinations gave the best results in protection of kidney infection, compared to the control mice. The results of this study propose new promising vaccine combinations based on the FliC antigen and Montanide against UTI caused by UPEC. PMID:23220068

Karam, Mohammad Reza Asadi; Oloomi, Mana; Mahdavi, Mehdi; Habibi, Mehri; Bouzari, Saeid

2013-05-01

83

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

PubMed

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. PMID:22988014

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

2012-12-01

84

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

PubMed

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. PMID:23030674

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

2013-02-01

85

Inhibition of uropathogenic Escherichia coli by cranberry juice: a new antiadherence assay.  

PubMed

A combination of microplate technology and turbidity assessment for testing the adherence of P-fimbriated Escherichia coli to human uroepithelial cell line T24, validated with the addition of the known inhibitor 4-O-alpha-D-galactopyranosyl-alpha-D-galactopyranose (galabiose), resulted in a high-throughput, biologically relevant assessment of cranberry (Vaccinium macrocarpon). P-fimbriated ATCC E. coli strains 25922, 29194, and 49161 were inhibited by galabiose. ATCC 29194, a representative urine isolate containing the papGII allele (Class II fimbrial adhesin) and demonstrating the most significant inhibition in the presence of galabiose, was chosen for further testing. In this assay, a low-polarity fraction of cranberry juice cocktail demonstrated dose-dependent inhibition of E. coli adherence. Reported here, for the first time in V. macrocarpon, are 1-O-methylgalactose, prunin, and phlorizin, identified in an active fraction of cranberry juice concentrate. This in vitro assay will be useful for the standardization of cranberry dietary supplements and is currently being used for bioassay-guided fractionation of cranberry juice concentrate. PMID:16277386

Turner, Allison; Chen, Shao-Nong; Joike, Michele K; Pendland, Susan L; Pauli, Guido F; Farnsworth, Norman R

2005-11-16

86

The multifunctional protein YdiV represses P fimbria-mediated adherence in uropathogenic Escherichia coli.  

PubMed

YdiV, a degenerate EAL domain protein, represses motility by interacting with FlhD to abolish FlhDC interaction with DNA. Here, we demonstrate that deletion of ydiV dysregulates coordinate control of motility and adherence by increasing adherence of Escherichia coli CFT073 to a bladder epithelial cell line by specifically increasing production of P fimbriae. Interestingly, only one of the two P fimbrial operons, pap_2, present in the genome of E. coli CFT073 was upregulated. This derepression of the pap_2 operon is abolished following deletion of either cya or crp, demonstrating cyclic AMP (cAMP)-dependent activation of the P fimbrial operon. However, the absence of YdiV does not affect the gene expression of cya and crp, and loss of SdiA in the ydiV mutant does not affect the derepression of the pap_2 operon, suggesting that YdiV control of adherence acts in response to cAMP levels. Deletion of ydiV increases motility by increasing expression of fliA, suggesting that in E. coli CFT073, YdiV regulates motility by the same mechanism as that described previously for commensal E. coli strains. Furthermore, analysis of site-directed mutations found two putative Mg(2+)-binding residues of four conserved YdiV residues (E29 and Q219) that were involved in regulation of motility and FliC production, while two conserved c-di-GMP-binding residues (D156 and D165) only affected motility. None of the four conserved YdiV residues appeared to affect regulation of adherence. Therefore, we propose a model in which a degenerate EAL, YdiV, utilizes different domains to regulate motility through interaction with FlhD and adherence to epithelial cells through cAMP-dependent effects on the pap_2 promoter. PMID:23667238

Spurbeck, Rachel R; Alteri, Christopher J; Himpsl, Stephanie D; Mobley, Harry L T

2013-07-01

87

Fimbrial Profiles Predict Virulence of Uropathogenic Escherichia coli Strains: Contribution of Ygi and Yad Fimbriae?  

PubMed Central

Escherichia coli, a cause of ?90% of urinary tract infections (UTI), utilizes fimbrial adhesins to colonize the uroepithelium. Pyelonephritis isolate E. coli CFT073 carries 12 fimbrial operons, 5 of which have never been studied. Using multiplex PCR, the prevalence of these 12 and 3 additional fimbrial types was determined for a collection of 303 E. coli isolates (57 human commensal, 32 animal commensal, 54 asymptomatic bacteriuria, 45 complicated UTI, 38 uncomplicated cystitis, and 77 pyelonephritis). The number of fimbrial types per E. coli isolate was distributed bimodally: those with low (3.2 ± 1.1) and those with high (8.3 ± 1.3) numbers of fimbrial types (means ± standard errors of the means). The fimbrial genes ygiL, yadN, yfcV, and c2395 were significantly more prevalent among urine isolates than human commensal isolates. The effect of deletion of Ygi and Yad fimbrial operons on growth, motility, biofilm formation, adherence to immortalized human epithelial cells, and pathogenesis in the mouse model of UTI was examined. Yad fimbriae were necessary for wild-type levels of adherence to a bladder epithelial cell line and for biofilm formation. Deletion of these fimbrial genes increased motility. Ygi fimbriae were necessary for wild-type levels of adherence to a human embryonic kidney cell line, biofilm formation, and in vivo fitness in the urine and kidneys. Complementation of each fimbrial mutant restored wild-type levels of motility, biofilm formation, adherence and, for ygi, in vivo fitness. A double deletion strain, ?ygi ?yad, was attenuated in the urine, bladder, and kidneys in the mouse model, demonstrating that these fimbriae contribute to uropathogenesis.

Spurbeck, Rachel R.; Stapleton, Ann E.; Johnson, James R.; Walk, Seth T.; Hooton, Thomas M.; Mobley, Harry L. T.

2011-01-01

88

The Multifunctional Protein YdiV Represses P Fimbria-Mediated Adherence in Uropathogenic Escherichia coli  

PubMed Central

YdiV, a degenerate EAL domain protein, represses motility by interacting with FlhD to abolish FlhDC interaction with DNA. Here, we demonstrate that deletion of ydiV dysregulates coordinate control of motility and adherence by increasing adherence of Escherichia coli CFT073 to a bladder epithelial cell line by specifically increasing production of P fimbriae. Interestingly, only one of the two P fimbrial operons, pap_2, present in the genome of E. coli CFT073 was upregulated. This derepression of the pap_2 operon is abolished following deletion of either cya or crp, demonstrating cyclic AMP (cAMP)-dependent activation of the P fimbrial operon. However, the absence of YdiV does not affect the gene expression of cya and crp, and loss of SdiA in the ydiV mutant does not affect the derepression of the pap_2 operon, suggesting that YdiV control of adherence acts in response to cAMP levels. Deletion of ydiV increases motility by increasing expression of fliA, suggesting that in E. coli CFT073, YdiV regulates motility by the same mechanism as that described previously for commensal E. coli strains. Furthermore, analysis of site-directed mutations found two putative Mg2+-binding residues of four conserved YdiV residues (E29 and Q219) that were involved in regulation of motility and FliC production, while two conserved c-di-GMP-binding residues (D156 and D165) only affected motility. None of the four conserved YdiV residues appeared to affect regulation of adherence. Therefore, we propose a model in which a degenerate EAL, YdiV, utilizes different domains to regulate motility through interaction with FlhD and adherence to epithelial cells through cAMP-dependent effects on the pap_2 promoter.

Spurbeck, Rachel R.; Alteri, Christopher J.; Himpsl, Stephanie D.

2013-01-01

89

OmpR regulation of the uropathogenic Escherichia coli fimB gene in an acidic/high osmolality environment.  

PubMed

Uropathogenic Escherichia coli (UPEC) causes more than 90?% of all human urinary tract infections through type 1 piliated UPEC cells binding to bladder epithelial cells. The FimB and FimE site-specific recombinases orient the fimS element containing the fimA structural gene promoter. Regulation of fimB and fimE depends on environmental pH and osmolality. The EnvZ/OmpR two-component system affects osmoregulation in E. coli. To ascertain if OmpR directly regulated the fimB gene promoters, gel mobility shift and DNase I footprinting experiments were performed using OmpR or phosphorylated OmpR (OmpR-P) mixed with the fimB promoter regions of UPEC strain NU149. Both OmpR-P and OmpR bound weakly to one fimB promoter. Because there was weak binding to one fimB promoter, strain NU149 was grown in different pH and osmolality environments, and total RNAs were extracted from each population and converted to cDNAs. Quantitative reverse-transcriptase PCR showed no differences in ompR transcription among the different growth conditions. Conversely, Western blots showed a significant increase in OmpR protein in UPEC cells grown in a combined low pH/high osmolality environment versus a neutral pH/high osmolality environment. In a high osmolality environment, the ompR mutant expressed more fimB transcripts and Phase-ON positioning of the fimS element as well as higher type 1 pili levels than wild-type cells. Together these results suggest that OmpR may be post-transcriptionally regulated in UPEC cells growing in a low pH/high osmolality environment, which regulates fimB in UPEC. PMID:23175504

Rentschler, Ann E; Lovrich, Steven D; Fitton, Robert; Enos-Berlage, Jodi; Schwan, William R

2013-02-01

90

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  

Microsoft Academic Search

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

DEBRA M. GUYER; JYH-SHYANG KAO; HARRY L. T. MOBLEY

91

Quinolones induce partial or total loss of pathogenicity islands in uropathogenic Escherichia coli by SOS-dependent or -independent pathways, respectively.  

PubMed

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

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

2006-02-01

92

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

PubMed Central

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 Ĺ-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 unidentified target proteins, respectively. These findings open new perspectives in both antigen design and for the identification of a functional role for this protective antigen.

2013-01-01

93

DNA sequences of three papA genes from uropathogenic Escherichia coli strains: evidence of structural and serological conservation.  

PubMed Central

Pyelonephritis-associated pili (Pap) are important in the pathogenesis of ascending, unobstructive Escherichia coli-caused renal infections because these surface bacterial organelles mediate digalactoside-specific binding to host uroepithelial cells. Pap are composed of many different polypeptides, of which only the tip proteins mediate specific binding. The PapA moiety polymerizes to form the bulk of the pilus structure and has been employed in vaccines despite its lack of Gal alpha(1-4)Gal receptor specificity. Animal recipients of PapA pilus-based vaccines are protected against experimental pyelonephritis caused by homologous and heterologous Gal-Gal-binding uropathogenic E. coli strains. Specific PapA immunoglobulin G antibodies in urine are correlated with protection in these infection models. The nucleotide sequences of the gene encoding PapA were determined for three E. coli clones expressing F7(1), F7(2), and F9 pili and were compared with corresponding sequences for other F serotypes. Specific rabbit antisera were employed in enzyme-linked immunosorbent assays to study the cross-reactivity between Gal-Gal pili purified from recombinant strains expressing F7(1), F7(2), F9, or F13 pili and among 60 Gal-Gal-binding wild-type strains. We present data which corroborate the concept that papA genes are highly homologous and encode proteins which exhibit greater than 70% homology among pili of different serotypes. The differences primarily occur in the cysteine-cysteine loop and variable regions and constitute the basis for serological diversity of these pili. Although there are differences in primary structures among these pili, antisera raised against pili of one serotype cross-reacted frequently with many other Gal-Gal pili of different serotypes. Furthermore, antisera raised against pili of the F13 serotype cross-reacted strongly or moderately with 52 (86%) of 60 wild-type Gal-Gal-binding E. coli strains. These data suggest that there are common immunogenic domains among these proteins. These additional data further support the hypothesis that broadly cross-protective PapA pilus vaccines for the immunoprophylaxis of pyelonephritis might be developed.

Denich, K; Blyn, L B; Craiu, A; Braaten, B A; Hardy, J; Low, D A; O'Hanley, P D

1991-01-01

94

Cytotoxic Necrotizing Factor 1 and Hemolysin from Uropathogenic Escherichia coli Elicit Different Host Responses in the Murine Bladder  

PubMed Central

Cytotoxic necrotizing factor 1 (CNF1) and hemolysin (HlyA1) are toxins produced by uropathogenic Escherichia coli (UPEC). We previously showed that these toxins contribute to the inflammation and tissue damage seen in a mouse model of ascending urinary tract infection. CNF1 constitutively activates small Rho GTPases by deamidation of a conserved glutamine residue, and HlyA1 forms pores in eukaryotic cell membranes. In this study, we used cDNA microarrays of bladder tissue isolated from mice infected intraurethrally with wild-type CP9, CP9cnf1, or CP9?hlyA to further evaluate the role that each toxin plays in the host response to UPEC. Regardless of the strain used, we found that UPEC itself elicited a significant change in host gene expression 24 h after inoculation. The largest numbers of upregulated genes were in the cytokine and chemokine signaling and Toll-like receptor signaling pathways. CNF1 exerted a strong positive influence on expression of genes involved in innate immunity and signal transduction and a negative impact on metabolism- and transport-associated genes. HlyA1 evoked an increase in expression of genes that encode innate immunity factors and a decrease in expression of genes involved in cytoskeletal and metabolic processes. Multiplex cytokine and myeloperoxidase assays corroborated our finding that a strong proinflammatory response was elicited by all strains tested. Bladders challenged intraurethrally with purified CNF1 displayed pathology similar to but significantly less intense than the pathology that we observed in CP9-challenged mice. Our data demonstrate substantial roles for CNF1 and HlyA1 in initiation of a strong proinflammatory response to UPEC in the bladder.

Garcia, Tamako A.; Ventura, Christy L.; Smith, Mark A.; Merrell, D. Scott

2013-01-01

95

Lifting the Mask: Identification of New Small Molecule Inhibitors of Uropathogenic Escherichia coli Group 2 Capsule Biogenesis  

PubMed Central

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.

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

96

Cytotoxic necrotizing factor 1 and hemolysin from uropathogenic Escherichia coli elicit different host responses in the murine bladder.  

PubMed

Cytotoxic necrotizing factor 1 (CNF1) and hemolysin (HlyA1) are toxins produced by uropathogenic Escherichia coli (UPEC). We previously showed that these toxins contribute to the inflammation and tissue damage seen in a mouse model of ascending urinary tract infection. CNF1 constitutively activates small Rho GTPases by deamidation of a conserved glutamine residue, and HlyA1 forms pores in eukaryotic cell membranes. In this study, we used cDNA microarrays of bladder tissue isolated from mice infected intraurethrally with wild-type CP9, CP9cnf1, or CP9?hlyA to further evaluate the role that each toxin plays in the host response to UPEC. Regardless of the strain used, we found that UPEC itself elicited a significant change in host gene expression 24 h after inoculation. The largest numbers of upregulated genes were in the cytokine and chemokine signaling and Toll-like receptor signaling pathways. CNF1 exerted a strong positive influence on expression of genes involved in innate immunity and signal transduction and a negative impact on metabolism- and transport-associated genes. HlyA1 evoked an increase in expression of genes that encode innate immunity factors and a decrease in expression of genes involved in cytoskeletal and metabolic processes. Multiplex cytokine and myeloperoxidase assays corroborated our finding that a strong proinflammatory response was elicited by all strains tested. Bladders challenged intraurethrally with purified CNF1 displayed pathology similar to but significantly less intense than the pathology that we observed in CP9-challenged mice. Our data demonstrate substantial roles for CNF1 and HlyA1 in initiation of a strong proinflammatory response to UPEC in the bladder. PMID:23090961

Garcia, Tamako A; Ventura, Christy L; Smith, Mark A; Merrell, D Scott; O'Brien, Alison D

2013-01-01

97

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

PubMed

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. PMID:23115037

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

2013-01-01

98

Surfactant Protein D Inhibits Adherence of Uropathogenic Escherichia coli to the Bladder Epithelial Cells and the Bacterium-induced Cytotoxicity  

PubMed Central

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 Ca2+-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.

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

2012-01-01

99

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

PubMed Central

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 uropathogenic E. coli.

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

2000-01-01

100

Multiresistant uropathogenic extended-spectrum ?-lactamase (ESBL)-producing Escherichia coli are susceptible to the carbon monoxide releasing molecule-2 (CORM-2).  

PubMed

Carbon monoxide (CO) releasing molecules (CO-RMs) have been shown to inhibit growth of commensal Escherichia coli (E. coli). In the present study we examined the effect of CORM-2 on uropathogenic E. coli (UPEC) that produces extended-spectrum ?-lactamase (ESBL). Viability experiments showed that CORM-2 inhibited the growth of several different ESBL-producing UPEC isolates and that 500 ?M CORM-2 had a bactericidal effect within 4 h. The bactericidal effect of CORM-2 was significantly more pronounced than the effect of the antibiotic nitrofurantoin. CORM-2 demonstrated a low level of cytotoxicity in eukaryotic cells (human bladder epithelial cell line 5637) at the concentrations and time-points where the antibacterial effect was obtained. Real-time RT-PCR studies of different virulence genes showed that the expression of capsule group II kpsMT II and serum resistance traT was reduced and that some genes encoding iron acquisition systems were altered by CORM-2. Our results demonstrate that CORM-2 has a fast bactericidal effect against multiresistant ESBL-producing UPEC isolates, and also identify some putative UPEC virulence factors as targets for CORM-2. CO-RMs may be candidate drugs for further studies in the field of finding new therapeutic approaches for treatment of uropathogenic ESBLproducing E. coli. PMID:24361394

Bang, Charlotte Sahlberg; Kruse, Robert; Demirel, Isak; Onnberg, Anna; Söderquist, Bo; Persson, Katarina

2014-01-01

101

Absence of ZnuABC-mediated zinc uptake affects virulence-associated phenotypes of uropathogenic Escherichia coli CFT073 under Zn(II)-depleted conditions  

PubMed Central

In an effort to uncover the role of the high affinity Zn(II) uptake system in uropathogenic Escherichia coli CFT073, we deleted the znuB gene, which encodes for the transmembrane component of the ZnuABC transporter system. The null mutant for znuB did not grow on minimal medium unless supplemented with excess Zn(II) (50 µM ZnCl2). In contrast, the E. coli K-12 ?znuB cell line grew well on minimal medium that was not supplemented with Zn(II). The ?znuB mutant was significantly deficient in formation of biofilm under static conditions and also showed a substantially-reduced migration front of swarm cells. Because motility and biofilm formation are important for E. coli CFT073 pathogenicity, we propose that the high affinity Zn(II) uptake system may contribute to the virulence of this pathogen in the urinary tract.

Gunasekera, Thusitha S.; Herre, Andrew H.; Crowder, Michael W.

2009-01-01

102

Effect of glucose and pH on uropathogenic and non-uropathogenic Escherichia coli: studies with urine from diabetic and non-diabetic individuals  

Microsoft Academic Search

It is generally assumed that one of the reasons why diabetics are more susceptible to urinary tract infections than non-diabetics is their 'sweet urine'. However, very little information is available on this subject. Therefore, the growth rates of different Escherichia coli strains were studied in human urine with and without added glucose and with and without a constant pH, and

S. E. GEERLINGS; E. C. BROUWER; W. GAASTRA; J. VERHOEF; A. I. M. HOEPELMAN

1999-01-01

103

Study of membrane attachment and in vivo co-localization of TerB protein from uropathogenic Escherichia coli KL53.  

PubMed

The tellurite resistance operon has been found in a wide range of bacteria. We have previously identified the ter operon (terXYW and terZABCDEF) of the uropathogenic strain Escherichia coli KL53. In this study, we use an innovative approach to identify putative protein-protein interaction partners for one of the essential tellurite resistance proteins - TerB. We observe that N-terminus of TerB attaches to the periplasmic membrane, while the C-terminus is partly localized in the cytoplasm. Subsequently, by methods of in vivo cross-linking and mass-spectroscopic analysis, we have determined the proteins from both the membrane and cytoplasmic fractions, which can potentially interact with TerB. PMID:21952438

Alekhina, Olga; Valkovicova, Lenka; Turna, Jan

2011-09-01

104

Characterization of an iroBCDEN Gene Cluster on a Transmissible Plasmid of Uropathogenic Escherichia coli: Evidence for Horizontal Transfer of a Chromosomal Virulence Factor  

PubMed Central

The chromosomal iroBCDEN gene cluster first described for Salmonella enterica is involved in the uptake of catecholate-type siderophore compounds. An orthologous gene cluster has recently been detected in Escherichia coli strains which cause extraintestinal disease. This E. coli iroBCDEN gene cluster has an impact on virulence and has been reported to be located in a pathogenicity island on the chromosome. In this study we characterized an iro gene cluster of a uropathogenic E. coli isolate which is located on a transmissible plasmid related to the R64 plasmid of S. enterica. This cluster is highly homologous to the chromosomal iro cluster of E. coli. When introduced into an E. coli fepA cir fiu aroB mutant, IroN, but not IroBCDE, mediated the utilization of structurally related catecholate siderophores, including 2,3-dihydroxybenzoyl-l-serine, 2,3-dihydroxybenzoyl-d-ornithine, 2,3-dihydroxybenzoic acid, and enterochelin. This study supports the idea of an ongoing horizontal transfer of putative virulence factors and the mobilization of single virulence gene clusters, which lead to a modular assembly of virulence determinants such as pathogenicity islands.

Sorsa, Liisa Johanna; Dufke, Severin; Heesemann, Jurgen; Schubert, Soren

2003-01-01

105

F9 fimbriae of uropathogenic Escherichia coli are expressed at low temperature and recognise Gal?1-3GlcNAc-containing glycans.  

PubMed

Uropathogenic Escherichia coli (UPEC) is the leading causative agent of urinary tract infections (UTI) in the developed world. Among the major virulence factors of UPEC, surface expressed adhesins mediate attachment and tissue tropism. UPEC strains typically possess a range of adhesins, with type 1 fimbriae and P fimbriae of the chaperone-usher class the best characterised. We previously identified and characterised F9 as a new chaperone-usher fimbrial type that mediates biofilm formation. However, the regulation and specific role of F9 fimbriae remained to be determined in the context of wild-type clinical UPEC strains. In this study we have assessed the distribution and genetic context of the f9 operon among diverse E. coli lineages and pathotypes and demonstrated that f9 genes are significantly more conserved in a UPEC strain collection in comparison to the well-defined E. coli reference (ECOR) collection. In the prototypic UPEC strain CFT073, the global regulator protein H-NS was identified as a transcriptional repressor of f9 gene expression at 37°C through its ability to bind directly to the f9 promoter region. F9 fimbriae expression was demonstrated at 20°C, representing the first evidence of functional F9 fimbriae expression by wild-type E. coli. Finally, glycan array analysis demonstrated that F9 fimbriae recognise and bind to terminal Gal?1-3GlcNAc structures. PMID:24671091

Wurpel, Daniël J; Totsika, Makrina; Allsopp, Luke P; Hartley-Tassell, Lauren E; Day, Christopher J; Peters, Kate M; Sarkar, Sohinee; Ulett, Glen C; Yang, Ji; Tiralongo, Joe; Strugnell, Richard A; Jennings, Michael P; Schembri, Mark A

2014-01-01

106

UpaH Is a Newly Identified Autotransporter Protein That Contributes to Biofilm Formation and Bladder Colonization by Uropathogenic Escherichia coli CFT073?  

PubMed Central

Escherichia coli is the primary cause of urinary tract infection (UTI) in the developed world. The major factors associated with virulence of uropathogenic E. coli (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. In this study, we identified a new AT-encoding gene, termed upaH, present in a 6.5-kb unannotated intergenic region in the genome of the prototypic UPEC strain CFT073. Cloning and sequencing of the upaH gene from CFT073 revealed an intact 8.535-kb coding region, contrary to the published genome sequence. The upaH gene was widely distributed among a large collection of UPEC isolates as well as the E. coli Reference (ECOR) strain collection. Bioinformatic analyses suggest ?-helix as the predominant structure in the large N-terminal passenger (?) domain and a 12-strand ?-barrel for the C-terminal ?-domain of UpaH. We demonstrated that UpaH is expressed at the cell surface of CFT073 and promotes biofilm formation. In the mouse UTI model, deletion of the upaH gene in CFT073 and in two other UPEC strains did not significantly affect colonization of the bladder in single-challenge experiments. However, in competitive colonization experiments, CFT073 significantly outcompeted its upaH isogenic mutant strain in urine and the bladder.

Allsopp, Luke P.; Totsika, Makrina; Tree, Jai J.; Ulett, Glen C.; Mabbett, Amanda N.; Wells, Timothy J.; Kobe, Bostjan; Beatson, Scott A.; Schembri, Mark A.

2010-01-01

107

Extended-spectrum ?-lactamase/AmpC-producing uropathogenic Escherichia coli from HIV patients: do they have a low virulence score?  

PubMed

Extended-spectrum ?-lactamase (ESBL) production and quinolone resistance are often associated in enterobacteria. Prior exposure to 3G cephalosporins/quinolones accelerates the risk of resistance to both these groups of antibiotics. Hence, information on the antimicrobial resistance pattern of uropathogenic Escherichia coli (UPEC) isolates is important to better formulate the guidelines for the empirical therapy of urinary tract infection in the context of HIV/AIDS. The aim of this study was to determine the incidence of ESBL/AmpC and fluoroquinolone (FQ) resistance among urinary E. coli isolates and to establish the association of extraintestinal virulence and phylogenetic distribution with antibiotic resistance and host immunocompromisation. Accordingly, 118 urinary Escherichia coli isolates from HIV (n = 76) and non-HIV antenatal patients (n = 42) from Chennai, South India, were analysed for the presence of five virulence-associated genes (VAGs): pap, sfa/foc, afa/dra, iutA and kpsMII. Compared with the susceptible HIV isolates, the majority of the ESBL(+)AmpC(+)FQ(R) isolates harboured iutA (66.7%) and pap (40%). The FQ-resistant HIV isolates were significantly enriched for iutA (67.8%) and kpsMII (47.5%) and qualified as UPEC (54.2%), while a majority of the FQ-susceptible isolates from the non-HIV patients were found to harbour pap (48.4%), sfa/foc (41.9%) and kpsMII (48.4%) and were classified as UPEC (40.5%). We conclude that antibiotic-resistant (ESBL(+)AmpC(+)and/or FQ(R)) phylogroup D isolates with limited virulence are competent enough to establish infections in HIV patients, while among non-HIV patients, an array of virulence factors is essential for E. coli to overcome host defences irrespective of antibiotic resistance. PMID:23161767

Padmavathy, Kesavaram; Padma, Krishnan; Rajasekaran, Sikhamani

2013-03-01

108

Hemagglutination and biofilm formation as virulence markers of uropathogenic Escherichia coli in acute urinary tract infections and urolithiasis  

PubMed Central

Introduction: Urinary tract infections (UTI) are a major public health concern in developing countries. Most UTIs are caused by E. coli, accounting for up to 90% of community-acquired UTIs (CAUTI). Recurrent UTI is considered as a major risk factor for urolithiasis. Virulence factors like adhesins and biofilm have been extensively studied by authors on UPEC isolated from recurrent UTI. The studies on isolates from infection stones in kidney are scanty. In a prospective study, we aimed to determine the expression of Haemagglutinins, (Type 1 and P fimbriae), Biofilm production and resistance pattern to common antibiotics of Uropathogenic E.coli (UPEC) isolates from Community acquired Acute Urinary Tract Infection(CAUTI) and Urolithiasis. Materials and Methods: A total of 43 UPEC isolates, 23 mid-stream urine (MSU) samples from patients with CAUTI attending Out Patient Departments and 20 from renal calculi of urolithiasis patients at the time of Percutaneous nephrolithostomy (PCNL) were included in the study and the expression of Haemagglutinins,(Type 1 and P fimbriae), Biofilm production and resistance pattern to common antibiotics was assessed. Results: A total of 43 UPEC isolates 23 from CAUTI and 20 from renal calculi were tested for production of biofilm and hemagglutinins. In CAUTI, biofilm producers were 56.52% and hemagglutinins were detected in all isolates 100%. In urolithiasis, biofilm producers were 100% but hemagglutinins were detected only in 70% of isolates. All isolates were resistant to multiple antibiotics used. CAUTI isolates were susceptible to 3rd generation cephalosporins, whereas urolithiasis isolates were resistant to 3rd generation cephalosporins and 25% were Extended Spectrum Beta Lactamases ESBL producers. Conclusions: HA mediated by type 1 fimbriae plays an important role in CAUTI (P < 0.001 highly significant), whereas, in chronic conditions like urolithiasis, biofilm plays an important role in persistence of infection and the role of hemagglutinins is less.

Maheswari, Uma B.; Palvai, Sunitha; Anuradha, Pattepu Rajalingam; Kammili, Nagamani

2013-01-01

109

Escherichia coli Sequence Type ST131 as an Emerging Fluoroquinolone-Resistant Uropathogen among Renal Transplant Recipients?  

PubMed Central

Among 40 Escherichia coli urine isolates from renal transplant recipients (Galveston, TX, 2003 to 2005), sequence type ST131 (O25:H4) was highly prevalent (representing 35% of isolates overall and 60% of fluoroquinolone-resistant isolates), virulent appearing, antimicrobial resistant (but extended-spectrum-cephalosporin susceptible), and associated with black race. Pulsotypes were diverse; some were linked to other locales. ST131 emerged significantly during the study period. These findings suggest that E. coli ST131 may constitute an important new multidrug-resistant threat to renal transplant recipients.

Johnson, James R.; Johnston, Brian; Clabots, Connie; Kuskowski, Michael A.; Pendyala, Swaroop; DebRoy, Chitrita; Nowicki, Bogdan; Rice, James

2010-01-01

110

Escherichia coli sequence type ST131 as an emerging fluoroquinolone-resistant uropathogen among renal transplant recipients.  

PubMed

Among 40 Escherichia coli urine isolates from renal transplant recipients (Galveston, TX, 2003 to 2005), sequence type ST131 (O25:H4) was highly prevalent (representing 35% of isolates overall and 60% of fluoroquinolone-resistant isolates), virulent appearing, antimicrobial resistant (but extended-spectrum-cephalosporin susceptible), and associated with black race. Pulsotypes were diverse; some were linked to other locales. ST131 emerged significantly during the study period. These findings suggest that E. coli ST131 may constitute an important new multidrug-resistant threat to renal transplant recipients. PMID:19917759

Johnson, James R; Johnston, Brian; Clabots, Connie; Kuskowski, Michael A; Pendyala, Swaroop; Debroy, Chitrita; Nowicki, Bogdan; Rice, James

2010-01-01

111

The type 1 pili regulator gene fimX and pathogenicity island PAI-X as molecular markers of uropathogenic Escherichia coli.  

PubMed

Uropathogenic Escherichia coli (UPEC) fall within a larger group of isolates producing extraintestinal disease. UPEC express type 1 pili as a critical virulence determinant mediating adherence to and invasion into urinary tract tissues. Type 1 pili expression is under regulation by a family of site-specific recombinases, including FimX, which is encoded from a genomic island called PAI-X for pathogenicity island of FimX. Using a new multiplex PCR, fimX and the additional PAI-X genes were found to be highly associated with UPEC (144/173?=?83.2?%), and more prevalent in UPEC of lower urinary tract origin (105/120?=?87.5?%) than upper urinary tract origin (39/53?=?74?%; P<0.05) or commensal isolates (28/78?=?36?%; P?0.0001). The Fim-like recombinase gene fimX is the only family member that has a significant association with UPEC compared to commensal isolates. Our results indicate PAI-X genes, including the type 1 pili regulator gene fimX, are highly prevalent among UPEC isolates and have a strong positive correlation with genomic virulence factors, suggesting a potential role for PAI-X in the extraintestinal pathogenic E. coli lifestyle. PMID:23744903

Bateman, Stacey L; Stapleton, Ann E; Stamm, Walter E; Hooton, Thomas M; Seed, Patrick C

2013-08-01

112

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

PubMed

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 (?g/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 ?g/ml) and greatest for enrofloxacin (1.55 ± 0.55 ?g/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. PMID:23136054

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

2013-02-01

113

Quantitative Analysis of Amyloid-Integrated Biofilms Formed by Uropathogenic Escherichia coli at the Air-Liquid Interface  

PubMed Central

Bacterial biofilms are complex multicellular assemblies, characterized by a heterogeneous extracellular polymeric matrix, that have emerged as hallmarks of persistent infectious diseases. New approaches and quantitative data are needed to elucidate the composition and architecture of biofilms, and such data need to be correlated with mechanical and physicochemical properties that relate to function. We performed a panel of interfacial rheological measurements during biofilm formation at the air-liquid interface by the Escherichia coli strain UTI89, which is noted for its importance in studies of urinary tract infection and for its assembly of functional amyloid fibers termed curli. Brewster-angle microscopy and measurements of the surface elasticity (Gs?) and stress-strain response provided sensitive and quantitative parameters that revealed distinct stages during bacterial colonization, aggregation, and eventual formation of a pellicle at the air-liquid interface. Pellicles that formed under conditions that upregulate curli production exhibited an increase in strength and viscoelastic properties as well as a greater ability to recover from stress-strain perturbation. The results suggest that curli, as hydrophobic extracellular amyloid fibers, enhance the strength, viscoelasticity, and resistance to strain of E. coli biofilms formed at the air-liquid interface.

Wu, Cynthia; Lim, Ji Youn; Fuller, Gerald G.; Cegelski, Lynette

2012-01-01

114

Necrosis is the dominant cell death pathway in uropathogenic Escherichia coli elicited epididymo-orchitis and is responsible for damage of rat testis.  

PubMed

Male infertility is a frequent medical condition, compromising approximately one in twenty men, with infections of the reproductive tract constituting a major etiological factor. Bacterial epididymo-orchitis results in acute inflammation most often caused by ascending canalicular infections from the urethra via the continuous male excurrent ductal system. Uropathogenic Escherichia coli (UPEC) represent a relevant pathogen in urogenital tract infections. To explore how bacteria can cause damage and cell loss and thus impair fertility, an in vivo epididymo-orchitis model was employed in rats by injecting UPEC strain CFT073 into the vas deference in close proximity to the epididymis. Seven days post infection bacteria were found predominantly in the testicular interstitial space. UPEC infection resulted in severe impairment of spermatogenesis by germ cell loss, damage of testicular somatic cells, a decrease in sperm numbers and a significant increase in TUNEL (+) cells. Activation of caspase-8 (extrinsic apoptotic pathway), caspase-3/-6 (intrinsic apoptotic pathway), caspase-1 (pyroptosis pathway) and the presence of 180 bp DNA fragments, all of which serve as indicators of the classical apoptotic pathway, were not observed in infected testis. Notably, electron microscopical examination revealed degenerative features of Sertoli cells (SC) in UPEC infected testis. Furthermore, the passive release of high mobility group protein B1 (HMGB1), as an indication of necrosis, was observed in vivo in infected testis. Thus, necrosis appears to be the dominant cell death pathway in UPEC infected testis. Substantial necrotic changes seen in Sertoli cells will contribute to impaired spermatogenesis by loss of function in supporting the dependent germ cells. PMID:23301002

Lu, Yongning; Bhushan, Sudhanshu; Tchatalbachev, Svetlin; Marconi, Marcelo; Bergmann, Martin; Weidner, Wolfgang; Chakraborty, Trinad; Meinhardt, Andreas

2013-01-01

115

A structural and biochemical basis for PAPS-independent sulfuryl transfer by aryl sulfotransferase from uropathogenic Escherichia coli.  

PubMed

Sulfotransferases are a versatile class of enzymes involved in numerous physiological processes. In mammals, adenosine 3'-phosphate-5'-phosphosulfate (PAPS) is the universal sulfuryl donor, and PAPS-dependent sulfurylation of small molecules, including hormones, sugars, and antibiotics, is a critical step in hepatic detoxification and extracellular signaling. In contrast, little is known about sulfotransferases in bacteria, which make use of sulfurylated molecules as mediators of cell-cell interactions and host-pathogen interactions. Bacterial arylsulfate sulfotransferases (also termed aryl sulfotransferases), in contrast to PAPS-dependent sulfotransferases, transfer sulfuryl groups exclusively among phenolic compounds in a PAPS-independent manner. Here, we report the crystal structure of the virulence factor arylsulfate sulfotransferase (ASST) from the prototypic, pyelonephritogenic Escherichia coli strain CFT073 at 2.0-A resolution, and 2 catalytic intermediates, at 2.1-A and 2.4-A resolution, with substrates bound in the active site. ASST is one of the largest periplasmic enzymes and its 3D structure differs fundamentally from all other structurally characterized sulfotransferases. Each 63.8-kDa subunit of the ASST homodimer comprises a 6-bladed beta-propeller domain and a C-terminal beta-sandwich domain. The active sites of the dimer are situated at the center of the channel formed by each beta-propeller and are defined by the side chains of His-252, His-356, Arg-374, and His-436. We show that ASST follows a ping-pong bi-bi reaction mechanism, in which the catalytic residue His-436 undergoes transient sulfurylation, a previously unreported covalent protein modification. The data provide a framework for understanding PAPS-independent sulfotransfer and a basis for drug design targeting this bacterial virulence factor. PMID:19036922

Malojci?, Goran; Owen, Robin L; Grimshaw, John P A; Brozzo, Maurice S; Dreher-Teo, Hiang; Glockshuber, Rudi

2008-12-01

116

Micropatterned Surfaces for Reducing the Risk of Catheter-Associated Urinary Tract Infection: An In Vitro Study on the Effect of Sharklet Micropatterned Surfaces to Inhibit Bacterial Colonization and Migration of Uropathogenic Escherichia coli  

PubMed Central

Abstract Background and Purpose Catheter-associated urinary tract infection (CAUTI) is the most common device-associated infection and can result in serious medical consequences. We studied the efficacy of a novel microscopic physical surface modification (Sharklet) for preventing bacterial colonization and migration of uropathogenic Escherichia coli on silicone elastomer. Materials and Methods In vitro growth assays evaluated E coli colonization using three variations of micropatterned silicone surfaces vs a smooth silicone control. Enumeration techniques included quantification of colonies on surfaces and analysis of bacterial area coverage and colony size. In vitro migration assays involved placement of micropatterned and smooth silicone rod segments between two agar islands to measure incidence of migration. Results All three variations of the Sharklet micropattern outperformed the control surfaces in inhibiting E coli colonization. On average, 47% reduction in colony-forming units (CFUs) and bacterial area coverage plus 77% reduction in colony size were achieved with the Sharklet surfaces in tryptic soy broth and artificial urine compared with the control nonpatterned surfaces. The incidence of E coli migration over the rod segments was reduced by more than 80% for the Sharklet transverse patterned rods compared with the unpatterned control rods. Conclusion The Sharklet micropattern is effective at inhibiting colonization and migration of a common uropathogen. This performance is achieved through a physical surface modification without the use of any antimicrobial agents. Because deterrence of bacterial colonization and migration is a critical step to prevent CAUTI, the Sharklet micropattern offers a novel concept in addressing this important problem.

Chung, Kenneth K.; McDaniel, Clinton J.; Darouiche, Rabih O.; Landman, Jaime; Brennan, Anthony B.

2011-01-01

117

Production of the Escherichia coli Common Pilus by Uropathogenic E. coli Is Associated with Adherence to HeLa and HTB-4 Cells and Invasion of Mouse Bladder Urothelium  

PubMed Central

Uropathogenic Escherichia coli (UPEC) strains cause urinary tract infections and employ type 1 and P pili in colonization of the bladder and kidney, respectively. Most intestinal and extra-intestinal E. coli strains produce a pilus called E. coli common pilus (ECP) involved in cell adherence and biofilm formation. However, the contribution of ECP to the interaction of UPEC with uroepithelial cells remains to be elucidated. Here, we report that prototypic UPEC strains CFT073 and F11 mutated in the major pilin structural gene ecpA are significantly deficient in adherence to cultured HeLa (cervix) and HTB-4 (bladder) epithelial cells in vitro as compared to their parental strains. Complementation of the ecpA mutant restored adherence to wild-type levels. UPEC strains produce ECP upon growth in Luria-Bertani broth or DMEM tissue culture medium preferentially at 26°C, during incubation with cultured epithelial cells in vitro at 37°C, and upon colonization of mouse bladder urothelium ex vivo. ECP was demonstrated on and inside exfoliated bladder epithelial cells present in the urine of urinary tract infection patients. The ability of the CFT073 ecpA mutant to invade the mouse tissue was significantly reduced. The presence of ECP correlated with the architecture of the biofilms produced by UPEC strains on inert surfaces. These data suggest that ECP can potentially be produced in the bladder environment and contribute to the adhesive and invasive capabilities of UPEC during its interaction with the host bladder. We propose that along with other known adhesins, ECP plays a synergistic role in the multi-step infection of the urinary tract.

Carrillo-Casas, Erika Margarita; Duran, Laura; Zhang, Yushan; Hernandez-Castro, Rigoberto; Puente, Jose L.; Daaka, Yehia; Giron, Jorge A.

2014-01-01

118

Escherichia Coli  

ERIC Educational Resources Information Center

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…

Goodsell, David S.

2009-01-01

119

Mobilisation and remobilisation of a large archetypal pathogenicity island of uropathogenic Escherichia coli in vitro support the role of conjugation for horizontal transfer of genomic islands  

PubMed Central

Background A substantial amount of data has been accumulated supporting the important role of genomic islands (GEIs) - including pathogenicity islands (PAIs) - in bacterial genome plasticity and the evolution of bacterial pathogens. Their instability and the high level sequence similarity of different (partial) islands suggest an exchange of PAIs between strains of the same or even different bacterial species by horizontal gene transfer (HGT). Transfer events of archetypal large genomic islands of enterobacteria which often lack genes required for mobilisation or transfer have been rarely investigated so far. Results To study mobilisation of such large genomic regions in prototypic uropathogenic E. coli (UPEC) strain 536, PAI II536 was supplemented with the mobRP4 region, an origin of replication (oriVR6K), an origin of transfer (oriTRP4) and a chloramphenicol resistance selection marker. In the presence of helper plasmid RP4, conjugative transfer of the 107-kb PAI II536 construct occured from strain 536 into an E. coli K-12 recipient. In transconjugants, PAI II536 existed either as a cytoplasmic circular intermediate (CI) or integrated site-specifically into the recipient's chromosome at the leuX tRNA gene. This locus is the chromosomal integration site of PAI II536 in UPEC strain 536. From the E. coli K-12 recipient, the chromosomal PAI II536 construct as well as the CIs could be successfully remobilised and inserted into leuX in a PAI II536 deletion mutant of E. coli 536. Conclusions Our results corroborate that mobilisation and conjugal transfer may contribute to evolution of bacterial pathogens through horizontal transfer of large chromosomal regions such as PAIs. Stabilisation of these mobile genetic elements in the bacterial chromosome result from selective loss of mobilisation and transfer functions of genomic islands.

2011-01-01

120

Plasmid-Related Quinolone Resistance Determinants in Epidemic Vibrio parahaemolyticus, Uropathogenic Escherichia coli, and Marine Bacteria from an Aquaculture Area in Chile.  

PubMed

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. PMID:24760167

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

2014-08-01

121

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

Microsoft Academic Search

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

Gerhard Zingler; Gabriele Blum; Ursula Falkenhagen; Ida Orskov; Frits Orskov; Jiirg Hacker; Manfred Ott

1993-01-01

122

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

PubMed Central

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.

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

1981-01-01

123

[Prevalence of beta-lactamase CTX-M-15 in phylogenetic groups of uropathogenic Escherichia coli isolated from patients in the community of Merida, Venezuela].  

PubMed

In this study we determined the prevalence of extended-spectrum beta-lactamases (ESBLs) in phylogenetic groups of uropathogenic E. coli (UPEC) isolated from patients in the community. Twenty one UPEC strains with reduced susceptibility to broad-spectrum cephalosporins were collected between January 2009 and July 2010, from patients with urinary tract infection who attended the Public Health Laboratory in Mérida, Venezuela. Genotypic characterization determined that all UPEC strains harbored blaBLEEs genes: 76.2% of the strains showed the presence of a single ESBL-producer gene, represented by blaCTX-M-15, whereas 23.8% of UPEC showed various combinations of bla genes (blacCTX-M-15 + blaTEM-1, blaCTX-M-15 + blaSHV and blaSHV + blaTEM-1). In this study, 61.9% of the isolates were placed in phylogroup A and the remaining strains were assigned to group B2 (38.1%). There was no evidence of spread of a particular UPEC clone; only seven strains belonged to a clonal group with an index of similarity greater than 85%. To our knowledge, this is the first description of blxCTX-M-15 in UPEC from patients with community-acquired urinary tract infections, which shows that Venezuela is also part of the so-called CTX-M-15 pandemic. The findings in this study, as well as its clinical and epidemiological implications, lead to the need for monitoring and controlling the spread of CTX-M-15 producing UPECs, not only regionally, but also nationwide. PMID:24758100

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

2014-03-01

124

Characteristics and prevalence within serogroup O4 of a J96-like clonal group of uropathogenic Escherichia coli O4:H5 containing the class I and class III alleles of papG.  

PubMed Central

The recent discovery of a geographically dispersed clonal group of Escherichia coli O4:H5 that includes prototypic uropathogenic strain J96 prompted us to determine the prevalence of J96-like strains within serogroup O4 and to further assess the characteristics of such strains. We used O:K:H;F serotyping, PCR-based genomic fingerprinting, pulsed-field gel electrophoresis (PFGE), multilocus enzyme electrophoresis (MLEE), and PCR detection of the three papG alleles and of the cytotoxic necrotizing factor 1 (cnf1) and aerobactin (aer) gene sequences to characterize the 15 O4 strains among 336 E. coli isolates from three clinical collections (187 from mixed-source bacteremia, 75 from urosepsis, and 74 from acute cystitis). J96-like strains constituted approximately half of the O4 strains, or 2% of the total population. In contrast to other O4 strains, the J96-like strains characteristically exhibited specific group III capsular antigens, the H5 flagellar and F13 fimbrial antigens, a distinctive PCR genomic fingerprint, the class III papG allele (plus, in 50% of strains, the enigmatic class I papG allele), and cnf1 but lacked aer. A subset of these strains was remarkably homogeneous with respect to all these characteristics and exhibited a distinctive PFGE fingerprint and MLEE pattern. These findings clarify the epidemiological relevance of J96 as a model extraintestinal pathogen, provide further evidence of the class I papG allele outside of strain J96, and offer insights into the evolution of E. coli serogroup O4.

Johnson, J R; Stapleton, A E; Russo, T A; Scheutz, F; Brown, J J; Maslow, J N

1997-01-01

125

Pyelonephritogenic Diffusely Adhering Escherichia coli EC7372 Harboring Dr-II Adhesin Carries Classical Uropathogenic Virulence Genes and Promotes Cell Lysis and Apoptosis in Polarized Epithelial Caco-2/TC7 Cells  

PubMed Central

Diffusely adhering Escherichia coli (DAEC) strains expressing adhesins of the Afa/Dr family bind to epithelial cells in a diffuse adherence pattern by recognizing a common receptor, the decay-accelerating factor (CD55). Recently, a novel CD55-binding adhesin, named Dr-II, was identified from the pyelonephritogenic strain EC7372. In this report, we show that despite the low level of sequence identity between Dr-II and other members of the Afa/Dr family, EC7372 induces pathophysiological effects similar to those induced by other Afa/Dr DAEC strains on the polarized epithelial cell line Caco-2/TC7. Specifically, the Dr-II adhesin was sufficient to promote CD55 and CD66e clustering around adhering bacteria and apical cytoskeleton rearrangements. Unlike other Afa/Dr DAEC strains, EC7372 expresses a functional hemolysin that promotes a rapid cellular lysis. In addition, cell death by apoptosis or necrosis was observed in EC7372-infected Caco-2/TC7 cells, depending on infection time. Our results indicate that EC7372 harbors a pathogenicity island (PAI) similar to the one described for the pyelonephritogenic strain CFT073, which carries both hly and pap operons. Cumulatively, our findings indicate that strain EC7372 can be considered a prototype of a subclass of Afa/Dr DAEC isolates that have acquired a PAI harboring several classical uropathogenic virulence genes.

Guignot, Julie; Breard, Jacqueline; Bernet-Camard, Marie-Francoise; Peiffer, Isabelle; Nowicki, Bogdan J.; Servin, Alain L.; Blanc-Potard, Anne-Beatrice

2000-01-01

126

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

PubMed

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. PMID:18190583

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

2008-04-01

127

Propolis can potentialise the anti-adhesion activity of proanthocyanidins on uropathogenic Escherichia coli in the prevention of recurrent urinary tract infections  

PubMed Central

Background Escherichia coli, the main bacteria found in recurrent urinary tract infections (UTI), is now frequently resistant to several currently used antibiotic treatments making new solutions essential. In this study, we evaluated the association propolis and proanthocyanidins type A to reduce bacterial anti-adhesion activity of E. coli on urothelial cells. Results This first double-blind, randomized, cross-over human trial included 5 volunteers that followed 6 different regimens with or without variable doses of cranberry and propolis with a washout period of at least 1 week between each regimen. Urine samples were collected at 0 h, 4-6 h, 12 h and 24 h after cranberry plus propolis or placebo capsule consumption. In vivo urinary bacterial anti-adhesion activity was assessed with a bioassay (a human T24 epithelial cell-line assay) and an in vivo Caenorhabditis elegans model. HPLC-PDA-MS was used to detect propolis and cranberry compounds in urine. Bioassays indicated significant bacterial anti-adhesion activity in urine collected from volunteers who had consumed cranberry plus propolis powder compared to placebo (p < 0.001). This inhibition was clearly dose-dependent, increasing with the amount of PACs and propolis equivalents consumed in each regimen. Results suggested that propolis had an additional effect with PACs and prevent a bacterial anti-adhesion effect over 1 day. An in vivo model showed that the E. coli strain presented a reduced ability to kill C. elegans after their growth in urine samples of patients who took cranberry plus propolis capsules. HPLC confirmed that propolis is excreted in urine. Conclusions This study presents an alternative to prevent recurrent UTI. Administration of PACs plus propolis once daily offers some protection against bacterial adhesion, bacterial multiplication and virulence in the urinary tract, representing an interesting new strategy to prevent recurrent UTI.

2011-01-01

128

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-?-lactamase-producing lineage.  

PubMed

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 bla(OXA) 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 emerged as an important cause of community-acquired urinary tract infections. PMID:23045357

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

2012-12-01

129

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-?-Lactamase-Producing Lineage  

PubMed Central

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 emerged as an important cause of community-acquired urinary tract infections.

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

2012-01-01

130

Salicylate increases the expression of marA and reduces in vitro biofilm formation in uropathogenic Escherichia coli by decreasing type 1 fimbriae expression  

PubMed Central

Escherichia coli is one of the most frequent bacteria implicated in biofilm formation, which is a dynamic process whose first step consists in bacteria adhesion to surfaces through type 1 fimbriae. Salicylate induces a number of morphological and physiological alterations in bacteria including the activation of the transcriptional regulator MarA. In this report the effects of salicylate on biofilm formation and their relationship with MarA were studied. An inverse relationship was observed between in vitro biofilm formation and salicylate concentration added to the culture medium. Salicylate increases the expression of marA and decreases the expression of fimA and fimB genes in the wild-type strain. In addition, the fimA and fimB expression was decreased in a MarR mutant in which marA was also overexpressed. In conclusion, the expression of type 1 fimbriae in presence of salicylate may be regulated by the level of marA expression through fimB regulator, albeit through neither the ompX nor the tolC genes.

Vila, Jordi; Soto, Sara M.

2012-01-01

131

Dosage effect on uropathogenic Escherichia coli anti-adhesion activity in urine following consumption of cranberry powder standardized for proanthocyanidin content: a multicentric randomized double blind study  

PubMed Central

Background Ingestion of cranberry (Vaccinium macrocarpon Ait.) has traditionally been utilized for prevention of urinary tract infections. The proanthocyanidins (PACs) in cranberry, in particular the A-type linkages have been implicated as important inhibitors of primarily P-fimbriated E. coli adhesion to uroepithelial cells. Additional experiments were required to investigate the persistence in urine samples over a broader time period, to determine the most effective dose per day and to determine if the urinary anti-adhesion effect following cranberry is detected within volunteers of different origins. Methods Two separate bioassays (a mannose-resistant hemagglutination assay and an original new human T24 epithelial cell-line assay) have assessed the ex-vivo urinary bacterial anti-adhesion activity on urines samples collected from 32 volunteers from Japan, Hungary, Spain and France in a randomized, double-blind versus placebo study. An in vivo Caenorhabditis elegans model was used to evaluate the influence of cranberry regimen on the virulence of E. coli strain. Results The results indicated a significant bacterial anti-adhesion activity in urine samples collected from volunteers that consumed cranberry powder compared to placebo (p < 0.001). This inhibition was clearly dose-dependent, prolonged (until 24 h with 72 mg of PAC) and increasing with the amount of PAC equivalents consumed in each cranberry powder regimen. An in vivo Caenorhabditis elegans model showed that cranberry acted against bacterial virulence: E. coli strain presented a reduced ability to kill worms after a growth in urines samples of patients who took cranberry capsules. This effect is particularly important with the regimen of 72 mg of PAC. Conclusions Administration of PAC-standardized cranberry powder at dosages containing 72 mg of PAC per day may offer some protection against bacterial adhesion and virulence in the urinary tract. This effect may offer a nyctohemeral protection.

2010-01-01

132

Pathogenic Escherichia coli  

Microsoft Academic Search

Few microorganisms are as versatile as Escherichia coli. An important member of the normal intestinal microflora of humans and other mammals, E. coli has also been widely exploited as a cloning host in recombinant DNA technology. But E. coli is more than just a laboratory workhorse or harmless intestinal inhabitant; it can also be a highly versatile, and frequently deadly,

James P. Nataro; Harry L. T. Mobley; James B. Kaper

2004-01-01

133

Role of Enteroaggregative Escherichia coli Virulence Factors in Uropathogenesis  

PubMed Central

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.

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

2013-01-01

134

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...

135

The effects of plant polyphenols on enterotoxigenic Escherichia coli adhesion and toxin binding  

Microsoft Academic Search

Pigs frequently encounter bacterial infections like enterotoxigenic Escherichia coli (ETEC). Due to rising concerns about antibiotic resistance of bacteria, there is a large demand for natural alternatives to combat these ETEC infections. Plant polyphenols have been suggested to reduce both the binding of cholera toxin to the GM1 ganglioside and the adhesion of uropathogenic E. coli to F1 fimbriae. In

R. Verhelst; M. Schroyen; N. Buys; T. Niewold

2010-01-01

136

Escherichia coli biofilms  

PubMed Central

Escherichia coli is a predominant species among facultative anaerobic bacteria of the gastrointestinal tract. Both its frequent community lifestyle and the availability of a wide array of genetic tools contributed to establish E. coli as a relevant model organism for the study of surface colonization. Several key factors, including different extracellular appendages, are implicated in E. coli surface colonization and their expression and activity are finely regulated, both in space and time, to ensure productive events leading to mature biofilm formation. This chapter will present known molecular mechanisms underlying biofilm development in both commensal and pathogenic E. coli.

Beloin, Christophe; Roux, Agnes; Ghigo, Jean-Marc

2008-01-01

137

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

PubMed

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. PMID:24239885

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

2014-01-10

138

Early Severe Inflammatory Responses to Uropathogenic E. coli Predispose to Chronic and Recurrent Urinary Tract Infection  

Microsoft Academic Search

Chronic infections are an increasing problem due to the aging population and the increase in antibiotic resistant organisms. Therefore, understanding the host-pathogen interactions that result in chronic infection is of great importance. Here, we investigate the molecular basis of chronic bacterial cystitis. We establish that introduction of uropathogenic E. coli (UPEC) into the bladders of C3H mice results in two

Thomas J. Hannan; Indira U. Mysorekar; Chia S. Hung; Megan L. Isaacson-Schmid; Scott J. Hultgren

2010-01-01

139

PREVALENCE OF TOXIN ENCODING GENES IN ESCHERICHIA COLI ISOLATES FROM URINARY TRACT INFECTIONS IN SLOVENIA PREVALENCA GENSKIH ZAPISOV ZA TOKSINE V IZOLATIH BAKTERIJE ESCHERICHIA COLI, PRIDOBLJENIH IZ VZORCEV URINA V SLOVENIJI  

Microsoft Academic Search

Methods 110 uropathogenic Escherichia coli strains (UPEC) obtained from the Institute of Micro- biology and Immunology of the Medical Faculty in Ljubljana were screened by PCR with primers specific for the following toxin encoding genes: hlyA (haemolysin), cnf1 (cytotoxic necrotising factor 1), usp (uropathogenic specific protein USP) and ibeA (invasin). Dot blot hybridisation experiments were performed to validate the PCR

Marjanca Star?i?-Erjavec; Veronika Križan-Hergouth; Borut Gubin

140

Recurrent Escherichia coli bacteremia.  

PubMed Central

Escherichia coli is the most common gram-negative organism associated with bacteremia. While recurrent E. coli urinary tract infections are well-described, recurrent E. coli bacteremia appears to be uncommon, with no episodes noted in multiple series of patients with gram-negative bacteremias. We report on 5 patients with recurrent bloodstream infections identified from a series of 163 patients with E. coli bacteremia. For each patient, the isolates from each episode were analyzed by pulsed-field gel electrophoresis (PFGE) and ribotyping and for the presence of E. coli virulence factors. For each of four patients, the index and recurrent episodes of bacteremia represented the same strain as defined by PFGE, and the strains were found to carry one or more virulence factors. The remaining patient, with two episodes of bloodstream infection separated by a 4-year interval, was infected with two isolates that did not carry any virulence factors and that were clonally related by ribotype analysis but differed by PFGE. All five patients had either a local host defense defect (three patients) or impaired systemic defenses (one patient) or both (one patient). Thus, recurrent E. coli bacteremia is likely to represent a multifactorial process that occurs in patients with impaired host defenses who are infected with virulent isolates. Images

Maslow, J N; Mulligan, M E; Arbeit, R D

1994-01-01

141

Study on the influence of cranberry extract ?uravit S·O·S(®) on the properties of uropathogenic Escherichia coli strains, their ability to form biofilm and its antioxidant properties.  

PubMed

Consumption of cranberries is known to exert positive health effects, especially against urinary tract infections. For this reason, presumably, they are widely used in folk medicine. Different aspects of cranberry phenolics activity were studied in individual papers but complex study in this matter is missing. The aim of the present study is to provide complex data concerning various aspects of cranberry extract activity. We studied the effects of subinhibitory concentrations of commercially available extract (?uravit S·O·S(®)) against two Escherichia coli strains isolated from urine of patients with pyelonephritis. Additionally the main extract anthocyanins were characterized. The activity of extract against lipid peroxidation and its radical scavenging ability were also assessed. ?uravit S·O·S(®) decreased the hydrophobicity of one of the studied E. coli strains, reduced swimming motility and adhesion to epithelial cells of both studied strains, it also limited the ability of bacteria to form biofilm. Expression of curli was not affected by cranberry extract, the assessment of P fimbriae expression was not reliable due to extract-induced agglutination of erythrocytes. Cranberry extract caused filamentation in both studied E. coli strains. It also showed pronounced antioxidant and radical scavenging properties. The properties of the studied cranberry extract show that it could be effectively used in prevention and/or elimination of urinary tract infections, specially the recurrent ones. PMID:22306419

Wojnicz, Dorota; Sycz, Zuzanna; Walkowski, Stefan; Gabrielska, Janina; Aleksandra, W?och; Alicja, Kucharska; Anna, Sokó?-??towska; Hendrich, Andrzej B

2012-04-15

142

Western blot analysis of anti-Escherichia coli serum immunoglobulins in women susceptible to recurrent urinary tract infections.  

PubMed

The basis for increased susceptibility of some women to recurrent urinary tract infections (UTIs) is not clear; increased susceptibility may be due to host factors that promote increased colonization of the vaginal and bladder mucosa with uropathogens or to decreased immune responses to uropathogens. Anti-Escherichia coli antibody specificities in sera from UTI patients and controls were comprehensively assessed to determine whether UTI-susceptible and -nonsusceptible women differed in their capacities to make antibodies to individual E. coli antigens. Sera were analyzed by one-dimensional Western blots using antigens prepared from uropathogenic E. coli. The results showed that sera from subjects without a history of recurrent UTIs contained IgG antibodies to specific E. coli antigens more often than did sera from UTI-susceptible patients. These data suggest that hyporesponsiveness to specific E. coli antigens may be linked to increased UTI susceptibility in some women. PMID:7594729

Hopkins, W J; Xing, Y; Dahmer, L A; Balish, E; Uehling, D T

1995-12-01

143

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

PubMed Central

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.

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

2001-01-01

144

Characterization of UrinaryEscherichia coliO75 Strains  

Microsoft Academic Search

Forty-four Escherichia coli O75 strains from patients with urinary tract infections were characterized by a variety of methods to obtain evidence of their clonal distribution and uropathogenic properties. By K and H antigen typing, the strains were divided into the following serotypes: O75:K5:H2(18 strains), O75:K95:H2(10 strains), O75:K95:H5 (7 strains), O75:K100:H5 (4 strains), and O75:K2:H55 (5 strains). Generally, biotyping proved to

WOLFGANG NIMMICH; WOLFGANG VOIGT; ANDGUNTRAM SELTMANN

145

Polarized Entry of Uropathogenic Afa/Dr Diffusely Adhering Escherichia coli Strain IH11128 into Human Epithelial Cells: Evidence for ?5?1 Integrin Recognition and Subsequent Internalization through a Pathway Involving Caveolae and Dynamic Unstable Microtubules  

PubMed Central

Afa/Dr diffusely adhering Escherichia coli strain IH11128 bacteria basolaterally entered polarized epithelial cells by a CD55- and CD66e-independent mechanism through interaction with the ?5?1 integrin and a pathway involving caveolae and dynamic microtubules (MTs). IH11128 invasion within HeLa cells was dramatically decreased after the cells were treated with the cholesterol-extracting drug methyl-?-cyclodextrin or the caveola-disrupting drug filipin. Disassembly of the dynamically unstable MT network by the compound 201-F resulted in a total abolition of IH11128 entry. In apically infected polarized fully differentiated Caco-2/TC7 cells, no IH11128 entry was observed. The entry of bacteria into apically IH11128-infected fully differentiated Caco-2/TC7 cells was greatly enhanced by treating cells with Ca2+-free medium supplemented with EGTA, a procedure that disrupts intercellular junctions and thus exposes the basolateral surface to bacteria. Basally infected fully differentiated polarized Caco-2/TC7 cells grown on inverted inserts mounted in chamber culture showed a highly significant level of intracellular IH11128 bacteria compared with cells subjected to the apical route of infection. No expression of CD55 and CD66e, the receptors for the Afa/Dr adhesins, was found at the basolateral domains of these cells. Consistent with the hypothesis that a cell-to-cell adhesion molecule acts as a receptor for polarized IH11128 entry, an antibody blockade using anti-?5?1 integrin polyclonal antibody completely abolished bacterial entry. Experiments conducted with the laboratory strain E. coli K-12 EC901 carrying the recombinant plasmid pBJN406, which expresses Dr hemagglutinin, demonstrated that the dra operon is involved in polarized entry of IH11128 bacteria. Examined as a function of cell differentiation, the number of internalized bacteria decreased dramatically beyond cell confluency. Surviving intracellular IH11128 bacteria residing intracellularly had no effect on the functional differentiation of Caco-2/TC7 cells.

Guignot, Julie; Bernet-Camard, Marie-Francoise; Pous, Christian; Plancon, Laure; Le Bouguenec, Chantal; Servin, Alain L.

2001-01-01

146

Enteropathogenic Escherichia coli: unravelling pathogenesis  

Microsoft Academic Search

Enteropathogenic Escherichia coli (EPEC) is a gram-negative bacterial pathogen that adheres to intestinal epithelial cells, causing diarrhoea. It constitutes a significant risk to human health and remains an important cause of infant mortality in developing countries. Although EPEC was the first E. coli strain to be implicated in human disease in the 1940s and 1950s, the mechanisms by which this

Huiwen Deborah Chen; Gad Frankel

2005-01-01

147

BarA-UvrY Two-Component System Regulates Virulence of Uropathogenic E. coli CFT073  

PubMed Central

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-? 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.

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

2012-01-01

148

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

PubMed

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-? 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. PMID:22363626

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

2012-01-01

149

Small-molecule inhibitors target Escherichia coli amyloid biogenesis and biofilm formation  

Microsoft Academic Search

Curli are functional extracellular amyloid fibers produced by uropathogenic Escherichia coli (UPEC) and other Enterobacteriaceae. Ring-fused 2-pyridones, such as FN075 and BibC6, inhibited curli biogenesis in UPEC and prevented the in vitro polymerization of the major curli subunit protein CsgA. The curlicides FN075 and BibC6 share a common chemical lineage with other ring-fused 2-pyridones termed pilicides. Pilicides inhibit the assembly

Lynette Cegelski; Jerome S Pinkner; Neal D Hammer; Corinne K Cusumano; Chia S Hung; Erik Chorell; Veronica Ĺberg; Jennifer N Walker; Patrick C Seed; Fredrik Almqvist; Matthew R Chapman; Scott J Hultgren

2009-01-01

150

Exploring the 3D Molecular Architecture of Escherichia coli Type 1 Pili  

Microsoft Academic Search

An integrated approach combining information gained by Fourier transformation, linear Markham superposition (real space) and mass-per-length measurement by scanning transmission electron microscopy was used to analyze the helical structure of the rod-like type 1 pili expressed by uropathogenic Escherichia coli strain W3110. The 3D reconstruction calculated from the experimental data showed the pili to be 6.9nm wide, right-handed helical tubes

Erik Hahn; Peter Wild; Uta Hermanns; Peter Sebbel; Rudi Glockshuber; Marcus Häner; Nicole Taschner; Peter Burkhard; Ueli Aebi; Shirley A. Müller

2002-01-01

151

Multiple drug resistance patterns in various phylogenetic groups of uropathogenic E.coli isolated from Faisalabad region of Pakistan.  

PubMed

The objective of this work was the phylogenetic characterization of local clinical isolates of uropathogenic E. coli with respect to drug resistance. A total of 59 uropathogenic E. coli responsible for community acquired urinary tract infections were included in this study. A triplex PCR was employed to segregate each isolate into four different phylogenetic groups (A, B1, B2 and D). Drug resistance was evaluated by disc diffusion method. The drugs used were ampicillin, aztreonam, cefixime, cefoperazone, ceftriaxone, cephradine among ?-lactam group; amikacin, gentamicin, and streptomycin among aminoglycosides; nalidixic acid and ciprofloxacin from quinolones; trimethoprim-sulfomethoxazole, and tetracycline. Among 59 uropathogenic E. coli isolates majority belonged to phylogenetic group B2 (50%) where as 19% each belonged to groups A and B1, and 12% to group D. All the isolates were multiple drug resistant (MDR). Most effective drugs against Group A, B1, and B2 were gentamicin, amikacin and cefixime; ceftriaxone and quinolones; and ceftriaxone and amikacin, respectively. Group D isolates were found to be highly resistant to all drugs. Our results have shown emergence of MDR isolates among uropathogenic E. coli with dominance of phylogenetic group B2. However, it was found that group D isolates were though less frequent, more drug resistant as compared with group B2. Groups A and B1 were relatively uncommon. Amikacin, ceftriaxone and gentamicin were the most effective drugs in general. PMID:24031752

Bashir, Saira; Sarwar, Yasra; Ali, Aamir; Mohsin, Mashkoor; Saeed, Muhammad Azeem; Tariq, Ayesha; Haque, Abdul

2011-10-01

152

Structural and functional integrity of spermatozoa is compromised as a consequence of acute uropathogenic E. coli-associated epididymitis.  

PubMed

Uropathogenic Escherichia coli (UPEC)-associated epididymitis is commonly diagnosed in outpatient settings. Although the infection can be successfully cleared using antimicrobial medications, 40% of patients unexplainably show persistent impaired semen parameters even after treatment. Our aim was to investigate whether pathogenic UPEC and its associated virulence factor hemolysin (hlyA) perturb the structural and functional integrity of both the epididymis and sperm, actions that may be responsible for the observed impairment and possibly a reduction of fertilization capabilities. Semen collected from patients diagnosed with E. coli-only related epididymitis showed that sperm counts were low 14 days postantimicrobial treatment regardless of hlyA status. At Day 84 following treatment, hlyA production correlated with approximately 4-fold lower sperm concentrations than in men with hlyA-negative strains. In vivo experiments with the hlyA-producing UPEC CFT073 strain in a murine epididymitis model showed that just 3 days postinfection, structural damage to the epididymis (epithelial damage, leukocyte infiltration, and edema formation) was present. This was more severe in UPEC CFT073 compared to nonpathogenic E. coli (NPEC 470) infection. Moreover, pathogenic UPEC strains prematurely activated the acrosome in vivo and in vitro. Raman microspectroscopy revealed that UPEC CFT073 undermined sperm integrity by inducing nuclear DNA damage. Consistent with these observations, the in vitro fertilization capability of hlyA-treated mouse sperm was completely abolished, although sperm were motile. These findings provide new insights into understanding the possible processes underlying clinical manifestations of acute epididymitis. PMID:23843239

Lang, Tali; Dechant, Maria; Sanchez, Victoria; Wistuba, Joachim; Boiani, Michele; Pilatz, Adrian; Stammler, Angelika; Middendorff, Ralf; Schuler, Gerhard; Bhushan, Sudhanshu; Tchatalbachev, Svetlin; Wübbeling, Frank; Burger, Martin; Chakraborty, Trinad; Mallidis, Con; Meinhardt, Andreas

2013-09-01

153

Characterization of fimbriae produced by enteropathogenic Escherichia coli.  

PubMed Central

Enteropathogenic Escherichia coli (EPEC) express rope-like bundles of filaments, termed bundle-forming pili (BFP) (J. A. Girón, A. S. Y. Ho, and G. K. Schoolnik, Science 254:710-713, 1991). Expression of BFP is associated with localized adherence to HEp-2 cells and the presence of the EPEC adherence factor plasmid. In this study, we describe the identification of rod-like fimbriae and fibrillae expressed simultaneously on the bacterial surface of three prototype EPEC strains. Upon fimbrial extraction from EPEC B171 (O111:NM), three fimbrial subunits with masses of 16.5, 15.5, and 14.7 kDa were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Their N-terminal amino acid sequence showed homology with F9 and F7(2) fimbriae of uropathogenic E. coli and F1845 of diffuse-adhering E. coli, respectively. The mixture of fimbrial subunits (called FB171) exhibited mannose-resistant agglutination of human erythrocytes only, and this activity was not inhibited by alpha-D-Gal(1-4)-beta-Gal disaccharide or any other described receptor analogs for P, S, F, M, G, and Dr hemagglutinins of uropathogenic E. coli, which suggests a different receptor specificity. Hemagglutination was inhibited by extracellular matrix glycoproteins, i.e., collagen type IV, laminin, and fibronectin, and to a lesser extent by gangliosides, fetuin, and asialofetuin. Scanning electron microscopic studies performed on clusters of bacteria adhering to HEp-2 cells revealed the presence of structures resembling BFP and rod-like fimbriae linking bacteria to bacteria and bacteria to the eukaryotic cell membrane. We suggest a role of these surface appendages in the interaction of EPEC with eukaryotic cells as well as in the overall pathogenesis of intestinal disease caused by EPEC. Images

Giron, J A; Ho, A S; Schoolnik, G K

1993-01-01

154

Uropathogenic E. coli Induce Different Immune Response in Testicular and Peritoneal Macrophages: Implications for Testicular Immune Privilege  

PubMed Central

Infertility affects one in seven couples and ascending bacterial infections of the male genitourinary tract by Escherichia coli are an important cause of male factor infertility. Thus understanding mechanisms by which immunocompetent cells such as testicular macrophages (TM) respond to infection and how bacterial pathogens manipulate defense pathways is of importance. Whole genome expression profiling of TM and peritoneal macrophages (PM) infected with uropathogenic E. coli (UPEC) revealed major differences in regulated genes. However, a multitude of genes implicated in calcium signaling pathways was a common feature which indicated a role of calcium-dependent nuclear factor of activated T cells (NFAT) signaling. UPEC-dependent NFAT activation was confirmed in both cultured TM and in TM in an in vivo UPEC infectious rat orchitis model. Elevated expression of NFATC2-regulated anti-inflammatory cytokines was found in TM (IL-4, IL-13) and PM (IL-3, IL-4, IL-13). NFATC2 is activated by rapid influx of calcium, an activity delineated to the pore forming toxin alpha-hemolysin by bacterial mutant analysis. Alpha-hemolysin suppressed IL-6 and TNF-? cytokine release from PM and caused differential activation of MAP kinase and AP-1 signaling pathways in TM and PM leading to reciprocal expression of key pro-inflammatory cytokines in PM (IL-1?, IL-1?, IL-6 downregulated) and TM (IL-1?, IL-6 upregulated). In addition, unlike PM, LPS-treated TM were refractory to NF?B activation shown by the absence of degradation of I?B? and lack of pro-inflammatory cytokine secretion (IL-6, TNF-?). Taken together, these results suggest a mechanism to the conundrum by which TM initiate immune responses to bacteria, while maintaining testicular immune privilege with its ability to tolerate neo-autoantigens expressed on developing spermatogenic cells.

Bhushan, Sudhanshu; Hossain, Hamid; Lu, Yongning; Geisler, Andreas; Tchatalbachev, Svetlin; Mikulski, Zbigniew; Schuler, Gerhard; Klug, Jorg; Pilatz, Adrian; Wagenlehner, Florian; Chakraborty, Trinad; Meinhardt, Andreas

2011-01-01

155

Draft Genome Sequence of Escherichia coli Strain ATCC 23506 (Serovar O10:K5:H4)  

PubMed Central

We report the 5.101-Mbp high-quality draft assembly of the Escherichia coli strain ATCC 23506 (serovar O10:K5:H4, also known as NCDC Bi 8337-41) genome. This uropathogenic strain, commonly referred to as E. coli K5, produces N-acetyl heparosan, a glycosaminoglycan-like capsular polysaccharide and precursor to the anticoagulant pharmaceutical heparin. Metabolic reconstruction of this genome will enable the prediction of gene deletions and overexpressions that lead to increased heparosan production.

Cress, Brady F.; Greene, Zachary R.; Linhardt, Robert J.

2013-01-01

156

Draft Genome Sequence of Escherichia coli Strain ATCC 23502 (Serovar O5:K4:H4)  

PubMed Central

We report the 4.682-Mbp high-quality draft assembly of the Escherichia coli strain ATCC 23502 (serovar O5:K4:H4, also known as NCDC U1-41) genome. This uropathogenic strain, commonly referred to as E. coli K4, produces a glycosaminoglycan-like capsular polysaccharide with a backbone similar in structure to unsulfated chondroitin, a precursor to the nutraceutically and potentially pharmaceutically valuable compound chondroitin sulfate. Metabolic reconstruction of this genome will enable prediction of genetic engineering strategies leading to increased chondroitin production.

Cress, Brady F.; Greene, Zachary R.; Linhardt, Robert J.

2013-01-01

157

Natural Killer Cell-Mediated Host Defense against Uropathogenic E. coli Is Counteracted by Bacterial HemolysinA-Dependent Killing of NK Cells  

PubMed Central

SUMMARY Uropathogenic Escherichia coli (UPEC) are a common cause of urinary tract infections (UTIs) in humans. While the importance of natural killer (NK) cells in innate immune protection against tumors and viral infections is well documented, their role in defense against bacterial infections is still emerging, and their involvement in UPEC-mediated UTI is practically unknown. Using a systematic mutagenesis approach, we found that UPEC adheres to NK cells primarily via its type I fimbriae and employs its hemolysinA toxin to kill NK cells. In the absence of hemolysinA, NK cells directly respond to the bacteria and secrete the cytokine TNF-?, which results in decreased bacterial numbers in vitro and reduction of bacterial burden in the infected bladders. Thus, NK cells control UPEC via TNF-? production, which UPEC counteracts by hemolysinA-mediated killing of NK cells, representing a previously unrecognized host defense and microbial counterattack mechanism in the context of UTI.

Gur, Chamutal; Coppenhagen-Glazer, Shunit; Rosenberg, Shilo; Yamin, Rachel; Enk, Jonatan; Glasner, Ariella; Bar-On, Yotam; Fleissig, Omer; Naor, Ronit; Abed, Jawad; Mevorach, Dror; Granot, Zvi; Bachrach, Gilad; Mandelboim, Ofer

2013-01-01

158

Natural killer cell-mediated host defense against uropathogenic E. coli is counteracted by bacterial hemolysinA-dependent killing of NK cells.  

PubMed

Uropathogenic Escherichia coli (UPEC) are a common cause of urinary tract infections (UTIs) in humans. While the importance of natural killer (NK) cells in innate immune protection against tumors and viral infections is well documented, their role in defense against bacterial infections is still emerging, and their involvement in UPEC-mediated UTI is practically unknown. Using a systematic mutagenesis approach, we found that UPEC adheres to NK cells primarily via its type I fimbriae and employs its hemolysinA toxin to kill NK cells. In the absence of hemolysinA, NK cells directly respond to the bacteria and secrete the cytokine TNF-?, which results in decreased bacterial numbers in vitro and reduction of bacterial burden in the infected bladders. Thus, NK cells control UPEC via TNF-? production, which UPEC counteracts by hemolysinA-mediated killing of NK cells, representing a previously unrecognized host defense and microbial counterattack mechanism in the context of UTI. PMID:24331464

Gur, Chamutal; Coppenhagen-Glazer, Shunit; Rosenberg, Shilo; Yamin, Rachel; Enk, Jonatan; Glasner, Ariella; Bar-On, Yotam; Fleissig, Omer; Naor, Ronit; Abed, Jawad; Mevorach, Dror; Granot, Zvi; Bachrach, Gilad; Mandelboim, Ofer

2013-12-11

159

Multidrug-Resistance and Extended Spectrum Beta-Lactamase Production in Uropathogenic E. Coli which were Isolated from Hospitalized Patients in Kolkata, India.  

PubMed

Background and Objective: Urinary Tract Infections (UTIs) are mostly caused by Escherichia coli. The appropriate therapy demands a current knowledge on the antimicrobial susceptibility pattern amongst these pathogens, as an inappropriate use of antibiotics may lead to complications and treatment failure. The UTIs which are caused by multidrug resistant Extended-Spectrum Beta-Lactamase (ESBL) producing bacteria further pose a severe problem, as the treatment options are limited. The aim of this study was to identify the pattern of multi drug resistance amongst the uropathogenic E. coli (UPEC) isolates which were obtained from hospitalized patients. Materials and Methods: Forty UPEC were isolated from 200 urine samples of hospitalized patients who were clinically suspected for UTIs. Antimicrobial susceptibility screening was performed by using 16 antibiotics, by the Kirby Bauer disk diffusion technique. The isolates which were resistant to the third generation cephalosporins were subjected to the ESBL confirmatory test by using drug and drug-inhibitor combination disks by following the CLSI guidelines. Results: All the 40 isolates except three were multidrug resistant. They showed the highest sensitivities for nitrofurantoin (72.5%) and amikacin (70%). A high level of resistance was observed against ampicillin (97.5%), nalidixic acid and cefelexin (95%), amoxicillin (92.5%), cotrimoxazole (82.5%) and ciprofloxacin (80%) respectively. Thirty different antibiotic resistance patterns were observed against the different antibiotics. Twenty-eight out of the 40 isolates were resistant to the third generation cephalosporins. However, the phenotypic test for the ESBL confirmation indicated that eighteen out of the twenty-eight isolates were ESBL producers and that eleven different drug resistance patterns were observed amongst them. Conclusions: Therefore, this study accounts for the varied multidrug resistance pattern amongst the uropathogenic E. coli which were isolated from hospitalized patients in Kolkata, an eastern region of India. Nitrofurantoin and amikacin should be assigned as potent drugs to treat this infection in this region of the country. These varied resistance patterns present major therapeutic and infection control challenges and they suggest a heterogeneous population of the uropathogenic E. coli isolates which circulate in this sector of India. PMID:23634394

Mukherjee, Mandira; Basu, Shreya; Mukherjee, Sandip Kumar; Majumder, Monalisa

2013-03-01

160

Enterobactin-Mediated Delivery of ?-Lactam Antibiotics Enhances Antibacterial Activity against Pathogenic Escherichia coli.  

PubMed

The design, synthesis, and characterization of enterobactin-antibiotic conjugates, hereafter Ent-Amp/Amx, where the ?-lactam antibiotics ampicillin (Amp) and amoxicillin (Amx) are linked to a monofunctionalized enterobactin scaffold via a stable poly(ethylene glycol) linker are reported. Under conditions of iron limitation, these siderophore-modified antibiotics provide enhanced antibacterial activity against Escherichia coli strains, including uropathogenic E. coli CFT073 and UTI89, enterohemorrhagic E. coli O157:H7, and enterotoxigenic E. coli O78:H11, compared to the parent ?-lactams. Studies with E. coli K-12 derivatives defective in ferric enterobactin transport reveal that the enhanced antibacterial activity observed for this strain requires the outer membrane ferric enterobactin transporter FepA. A remarkable 1000-fold decrease in minimum inhibitory concentration (MIC) value is observed for uropathogenic E. coli CFT073 relative to Amp/Amx, and time-kill kinetic studies demonstrate that Ent-Amp/Amx kill this strain more rapidly at 10-fold lower concentrations than the parent antibiotics. Moreover, Ent-Amp and Ent-Amx selectively kill E. coli CFT073 co-cultured with other bacterial species such as Staphylococcus aureus, and Ent-Amp exhibits low cytotoxicity against human T84 intestinal cells in both the apo and iron-bound forms. These studies demonstrate that the native enterobactin platform provides a means to effectively deliver antibacterial cargo across the outer membrane permeability barrier of Gram-negative pathogens utilizing enterobactin for iron acquisition. PMID:24927110

Zheng, Tengfei; Nolan, Elizabeth M

2014-07-01

161

Escherichia coli bactofection using Lipofectamine.  

PubMed

Successful gene delivery into mammalian cells using bactofection requires entry of the bacterial vector via cell surface integrin receptors followed by release of plasmid DNA into the cellular environment. We show, for the first time, that addition of the DNA transfection reagent Lipofectamine improves entry of invasive Escherichia coli into HeLa cells and enhances up to 2.8-fold green fluorescent protein (GFP) expression from a reporter plasmid. The addition of Lipofectamine may be applicable to other bacterial vectors to increase their DNA delivery efficiency into mammalian cells. PMID:23608053

Narayanan, Kumaran; Lee, Choon Weng; Radu, Aurelian; Sim, Edmund Ui Hang

2013-08-15

162

Escherichia coli isolates that carry vat, fyuA, chuA, and yfcV efficiently colonize the urinary tract.  

PubMed

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

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

2012-12-01

163

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

PubMed Central

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.

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

164

ENZYME BIOSYNTHESIS IN ESCHERICHIA COLI  

PubMed Central

Escherichia coli B synthesized ?-galactosidase and an enzyme system for D-xylose when exposed to lactose and xylose respectively in nitrogen-free media. The amount of ?-galactosidase formed in the absence of external nitrogen depended upon the nature of the medium in which the cells had originally been grown. Half as much of this enzyme was synthesized without exogenous nitrogen by cells taken from a nitrogen-rich medium as was formed by cells under favorable conditions with an external supply of nitrogen. Escherichia coli B contained a pool of nitrogen compounds soluble in 80 per cent ethanol and made up of several ninhydrin-positive components. One of these was identified chromatographically as glycine using an authentic radioactive sample. Another substance behaved like serine on the chromatograms. The internal pool of amino acids and peptides was large enough to account for the ?-galactosidase synthesized by cells exposed to lactose in a medium free of nitrogen. Some degree of interaction of the syntheses of the ?-galactosidase and xylose enzyme systems was observed in nitrogen-free media. This interaction produced a greater effect on the formation of ?-galactosidase and was attributed to a limiting factor(s) in the internal nitrogenous pool or to a limiting intermediate in enzyme synthesis.

Weinbaum, George; Mallette, M. F.

1959-01-01

165

Virulence factors in Escherichia coli urinary tract infection.  

PubMed Central

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

Johnson, J R

1991-01-01

166

Methionineless Death in Escherichia coli  

PubMed Central

Methionine auxotrophs of strains derived from Escherichia coli 15 lose their colony-forming ability when deprived of this amino acid. Late addition of methionine to liquid cultures did not restore plating efficiency but permitted growth of surviving cells. This phenomenon, termed methionineless death (mld), was not observed with methionine auxotrophs of E. coli strains B, W, or K12, nor was a similar amino acidless death observed with corresponding auxotrophs of E. coli 15 for arginine, tryptophan, proline, isoleucine, and leucine. Mld was not dependent upon the genetic site determining methionine auxotrophy, nor did it affect the decarboxylation of methionine or the stability of methionyl-transfer ribonucleic acid synthetase activity of starved cells. Death was not altered by the presence of spermine or spermidine but was abolished by the methionine analogue, ?-methylmethionine. Simultaneous starvation of another amino acid in a multiple auxotroph also significantly reduced mld, suggesting a possible role of protein synthesis. The onset of mld is correlated with a lower net increase of deoxyribonucleic acid.

Breitman, T. R.; Finkleman, A.; Rabinovitz, M.

1971-01-01

167

Escherichia coli - Marauding masquerading microbe  

PubMed Central

Background Escherichia coli is a rare cause of monoarticular septic arthritis, but is an even rarer cause of polyarticular septic arthritis. Case description We report an unusual case of polyarticular septic arthritis with an atypical presentation caused by E. coli, the source of which was a left pyelonephritis. Our patient developed E coli sepsis resulting in polyarticular septic arthritis (PASA) in the absence of typical risk factors except for pre-existing osteoarthritis. The joints involved were the hip, ankle, sternoclavicular and L5/S1 joints. Of interest, ankle pain was not reported or evident until correlated with nuclear medicine scans. Furthermore, sternoclavicular joint involvement presented as left shoulder pain, resulting in an initial misdiagnosis of left shoulder septic arthritis. The patient was treated with surgical washout and antibiotic therapy. He was subsequently discharged from rehabilitation having returned to his baseline level of mobility. Future consideration will be given to total hip arthroplasty. Literature review There are no reported cases of E. coli PASA involving more than three joints in the absence of any recognized risk factors for septic arthritis. Purpose and clinical relevance Asymptomatic involvement of joints can occur in polyarticular septic arthritis and should be considered in all cases of monoarticular septic arthritis (MASA). We believe that clinical suspicion is the key to early and comprehensive diagnosis of polyarticular septic arthritis particularly when presenting in an atypical fashion with an atypical pathogen. Strong consideration should be given to performing nuclear imaging in cases of monoarticular septic arthritis where polyarticular involvement cannot be definitively ruled out.

Lee, Amy; Coleman, Patrick

2013-01-01

168

Comparative Genomics of Escherichia coli Strains Causing Urinary Tract Infections ? †  

PubMed Central

The virulence determinants of uropathogenic Escherichia coli have been studied extensively over the years, but relatively little is known about what differentiates isolates causing various types of urinary tract infections. In this study, we compared the genomic profiles of 45 strains from a range of different clinical backgrounds, i.e., urosepsis, pyelonephritis, cystitis, and asymptomatic bacteriuria (ABU), using comparative genomic hybridization analysis. A microarray based on 31 complete E. coli sequences was used. It emerged that there is little correlation between the genotypes of the strains and their disease categories but strong correlation between the genotype and the phylogenetic group association. Also, very few genetic differences may exist between isolates causing symptomatic and asymptomatic infections. Only relatively few genes that could potentially differentiate between the individual disease categories were identified. Among these were two genomic islands, namely, pathogenicity island (PAI)-CFT073-serU and PAI-CFT073-pheU, which were significantly more associated with the pyelonephritis and urosepsis isolates than with the ABU and cystitis isolates. These two islands harbor genes encoding virulence factors, such as P fimbriae (pyelonephritis-associated fimbriae) and an important immunomodulatory protein, TcpC. It seems that both urovirulence and growth fitness can be attributed to an assortment of genes rather than to a specific gene set. Taken together, urovirulence and fitness are the results of the interplay of a mixture of factors taken from a rich menu of genes.

Vejborg, Rebecca Munk; Hancock, Viktoria; Schembri, Mark A.; Klemm, Per

2011-01-01

169

Galleria mellonella Infection Model Demonstrates High Lethality of ST69 and ST127 Uropathogenic E. coli  

PubMed Central

Galleria mellonella larvae are an alternative in vivo model for investigating bacterial pathogenicity. Here, we examined the pathogenicity of 71 isolates from five leading uropathogenic E. coli (UPEC) lineages using G. mellonella larvae. Larvae were challenged with a range of inoculum doses to determine the 50% lethal dose (LD50) and for analysis of survival outcome using Kaplan-Meier plots. Virulence was correlated with carriage of a panel of 29 virulence factors (VF). Larvae inoculated with ST69 and ST127 isolates (104 colony-forming units/larvae) showed significantly higher mortality rates than those infected with ST73, ST95 and ST131 isolates, killing 50% of the larvae within 24 hours. Interestingly, ST131 isolates were the least virulent. We observed that ST127 isolates are significantly associated with a higher VF-score than isolates of all other STs tested (P?0.0001), including ST69 (P<0.02), but one ST127 isolate (strain EC18) was avirulent. Comparative genomic analyses with virulent ST127 strains revealed an IS1 mediated deletion in the O-antigen cluster in strain EC18, which is likely to explain the lack of virulence in the larvae infection model. Virulence in the larvae was not correlated with serotype or phylogenetic group. This study illustrates that G. mellonella are an excellent tool for investigation of the virulence of UPEC strains. The findings also support our suggestion that the incidence of ST127 strains should be monitored, as these isolates have not yet been widely reported, but they clearly have a pathogenic potential greater than that of more widely recognised clones, including ST73, ST95 or ST131.

Alghoribi, Majed F.; Gibreel, Tarek M.; Dodgson, Andrew R.; Beatson, Scott A.; Upton, Mathew

2014-01-01

170

Size Fractionation of Exponentially Growing Escherichia coli  

Microsoft Academic Search

A new method for differentiating between bacteria of different sizes in a single population is used to show that the rate of synthesis of RNA in a population of Escherichia coli varies linearly with the size of the cell.

Haim Manor; Robert Haselkorn

1967-01-01

171

Maltoheptaose Promotes Nanoparticle Internalization by Escherichia coli  

PubMed Central

Nanoparticles conjugated with D-maltoheptaose (G7) showed a striking increase in the internalization by Escherichia coli. This applies to strains with and without the maltodextrin transport channel and particles ranging from a few to a hundred nanometers.

Jayawardena, Surangi; Jayawardana, Kalana; Chen, Xuan

2013-01-01

172

Influence of RecA on in vivo virulence and Shiga toxin 2 production in Escherichia coli pathogens  

Microsoft Academic Search

The enterohemorrhagicEscherichia coli(EHEC) O157:H7 strains 933 and 86–24 as well as the uropathogenicE. coli(UPEC) strain 536 were compared with their isogenicrecA mutants andrecAtrans-complemented strains in intravenous lethality and lung toxicity assays in mice. While the wild-type EHEC strains were fully virulent, the virulence of therecA mutants was strongly reduced. Complementation of the EHECrecA mutants with the clonedE. colirecA gene restored

Sibylle Fuchs; Inge Mühldorfer; Arthur Donohue-Rolfe; Monika Kerényi; Levente Emödy; Rossen Alexiev; Plamen Nenkov; Jörg Hacker

1999-01-01

173

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

PubMed Central

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.

2012-01-01

174

Escherichia coli O157 Cluster Evaluation  

PubMed Central

We investigated a multistate cluster of Escherichia coli O157:H7 isolates; pulsed-field gel electrophoresis subtyping, using a single enzyme, suggested an epidemiologic association. An investigation and additional subtyping, however, did not support the association. Confirmating E. coli O157 clusters with two or more restriction endonucleases is necessary before public health resources are allocated to follow-up investigations.

Hunter, Susan B.; Bidol, Sally A.; Dietrich, Stephen; Kincaid, Jennifer; Salehi, Ellen; Nicholson, Lisa; Genese, Carol Ann; Todd-Weinstein, Sarah; Marengo, Lisa; Kimura, Akiko C.; Brooks, John T.

2004-01-01

175

Genetics of Virulence in Enteroinvasive Escherichia coli.  

National Technical Information Service (NTIS)

The term enteroinvasive Escherichia coli (EIEC) is used to differentiate a small number of E. coli bioserotypes which can invade the intestinal mucosa and cause a dysenterylike syndrome similar to shigellosis. As shown in Table 1, the EIEC biotype is usua...

P. J. Sansonetti T. L. Hale E. V. Oaks

1985-01-01

176

The population genetics of commensal Escherichia coli  

Microsoft Academic Search

The primary habitat of Escherichia coli is the vertebrate gut, where it is the predominant aerobic organism, living in symbiosis with its host. Despite the occurrence of recombination events, the population structure is predominantly clonal, allowing the delineation of major phylogenetic groups. The genetic structure of commensal E. coli is shaped by multiple host and environmental factors, and the determinants

Olivier Tenaillon; David Skurnik; Bertrand Picard; Erick Denamur

2010-01-01

177

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

PubMed

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

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

2014-04-01

178

Succinate production in Escherichia coli  

PubMed Central

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.

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

2012-01-01

179

Characterization of Escherichia coli Isolates from Hospital Inpatients or Outpatients with Urinary Tract Infection  

PubMed Central

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.

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

2014-01-01

180

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

PubMed

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. PMID:24478469

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

181

Variation in endogenous oxidative stress in Escherichia coli natural isolates during growth in urine  

PubMed Central

Background Uropathogenic strains of Escherichia coli cause symptomatic infections whereas asymptomatic bacteriuria (ABU) strains are well adapted for growth in the human urinary tract, where they establish long-term bacteriuria. Human urine is a very complex growth medium that could be perceived by certain bacteria as a stressful environment. To investigate a possible imbalance between endogenous oxidative response and antioxidant mechanisms, lipid oxidative damage estimated as thiobarbituric acid reactive substances (TBARS) content was evaluated in twenty-one E. coli belonging to various pathovars and phylogenetic groups. Antioxidant defense mechanisms were also analysed. Results During exponential growth in urine, TBARS level differs between strains, without correlation with the ability to grow in urine which was similarly limited for commensal, ABU and uropathogenic strains. In addition, no correlation between TBARS level and the phylogroup or pathogenic group is apparent. The growth of ABU strain 83972 was associated with a high level of TBARS and more active antioxidant defenses that reduce the imbalance. Conclusions Our results indicate that growth capacity in urine is not a property of ABU strains. However, E. coli isolates respond very differently to this stressful environment. In strain ABU 83972, on one hand, the increased level of endogenous reactive oxygen species may be responsible for adaptive mutations. On the other hand, a more active antioxidant defense system could increase the capacity to colonize the bladder.

2012-01-01

182

Iron induces bimodal population development by Escherichia coli.  

PubMed

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. PMID:23359678

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

183

Clinical Implications of Enteroadherent Escherichia coli  

PubMed Central

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.

Arenas-Hernandez, Margarita M.P.; Martinez-Laguna, Ygnacio; Torres, Alfredo G.

2012-01-01

184

Infection strategies of enteric pathogenic Escherichia coli  

PubMed Central

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.

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

2012-01-01

185

Stability of Ribosomes from Streptomycin-Exposed Escherichia Coli.  

National Technical Information Service (NTIS)

Exposure of Escherichia coli to streptomycin resulted in a marked stabilization of their ribosomes to heat; ribosomes of streptomycin-resistant Escherichia coli were only stabilized slightly. Phenotypic expression of bacterial sensitivity or resistance to...

A. D. Wolfe F. E. Hahn

1968-01-01

186

Membrane filter method for enumerating Escherichia coli.  

PubMed Central

A membrane filter procedure for enumerating Escherichia coli was developed and evaluated. The method quantifies E. coli within 24 h without requiring subculture and identification of isolates. It incorporates a primary selective-differential medium for gram-negative, lactose-fermenting bacteria; resuscitation of weakened organisms by incubation for 2 h at 35 degrees C before incubation at 44.5 degrees C for 18 to 22 h; and an in situ urease test to differentiate E. coli from other thermotolerant, lactose-positive organisms. The recovery of E. coli from marine, estuarine, and freshwater samples exceeded 90%. Of the presumptively positive colonies, 91% were verified as E. coli. Less than 1% of all of the verified E. coli colonies failed to react typically.

Dufour, A P; Strickland, E R; Cabelli, V J

1981-01-01

187

Pathogenic Escherichia coli Found in Sewage Treatment Plants and Environmental Waters  

PubMed Central

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.

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

2012-01-01

188

Post-irradiation Recovery of Escherichia coli  

Microsoft Academic Search

RADIATION sensitivity of Escherichia coli strains is influenced by conditions for growth prior to and after radiation exposure. Stapleton and Engel1 have shown that E. coli B\\/r (CSH) grown in a buffered-peptone medium developed higher X-ray resistance. The cells grown in rich medium, however, might have become more exacting in their nutritional requirements and their recovery was limited on basal

J. S. Lee; R. O. Sinnhuber

1965-01-01

189

Molecular Archaeology of the Escherichia coli Genome  

Microsoft Academic Search

The availability of the complete sequence of Escherichia coli strain MG1655 provides the first opportunity to assess the overall impact of horizontal genetic transfer on the evolution of bacterial genomes. We found that 755 of 4,288 ORFs (547.8 kb) have been introduced into the E. coli genome in at least 234 lateral transfer events since this species diverged from the

Jeffrey G. Lawrence; Howard Ochman

1998-01-01

190

Endogenous endophthalmitis caused by Escherichia coli.  

PubMed

Endophthalmitis is a rare complication of Escherichia coli-induced septicemia. Nine cases of endogenous endophthalmitis caused by E. coli have been reported previously, all except one in patients with diabetes. The most common primary site of infection is the urinary tract. The course of illness is rapidly progressive with a poor visual prognosis. Concurrent systemic morbidity, including body abscesses and endocarditis, is high. We report an additional case of endogenous endophthalmitis from E. coli in a diabetic woman. Enucleation was required despite aggressive topical and systemic treatment. The pertinent literature is reviewed. PMID:8460886

Park, S B; Searl, S S; Aquavella, J V; Erdey, R A

1993-03-01

191

Beta-alanine synthesis in Escherichia coli.  

PubMed Central

The enzyme, aspartate 1-decarboxylase (L-aspartate 1-carboxy-lyase; EC 4.1.1.15), that catalyzes the reaction aspartate leads to beta-alanine + CO2 was found in extracts of Escherichia coli. panD mutants of E. coli are defective in beta-alanine biosynthesis and lack aspartate 1-decarboxylase. Therefore, the enzyme functions in the biosynthesis of the beta-alanine moiety of pantothenate. The genetic lesion in these mutants is closely linked to the other pantothenate (pan) loci of E. coli K-12. Images

Cronan, J E

1980-01-01

192

Synthetic polymer nanoparticles conjugated with FimHA from E. coli pili to emulate the bacterial mode of epithelial internalization  

PubMed Central

Amphiphilic block copolymer nanoparticles are conjugated with uropathogenic Escherichia coli type 1 pilus adhesin FimHA through amidation chemistry to enable bladder epithelial cell binding and internalization of the nanoparticles in vitro.

Lin, Lily Yun; Tiemann, Kristin M.; Li, Yali; Pinkner, Jerome S.; Walker, Jennifer N.; Hultgren, Scott J.; Hunstad, David A.; Wooley, Karen L.

2012-01-01

193

Regulation of Alcohol Fermentation by Escherichia Coli.  

National Technical Information Service (NTIS)

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 dehydrogenas...

D. P. Clark

1986-01-01

194

Enterotoxigenic Escherichia coli in veterinary medicine  

Microsoft Academic Search

Enterotoxigenic Escherichia coli (ETEC) infection is the most common type of colibacillosis of young animals (primarily pigs and calves), and it is a significant cause of diarrhoea among travellers and children in the developing world. The main virulence attributes of ETEC are adhesins and enterotoxins, which are mostly regulated on large plasmids. Almost all ETEC bacteria are known to adhere

Béla Nagy; Péter Zs. Fekete

2005-01-01

195

Leaner and meaner genomes in Escherichia coli  

PubMed Central

A 'better' Escherichia coli K-12 genome has recently been engineered in which about 15% of the genome has been removed by planned deletions. Comparison with related bacterial genomes that have undergone a natural reduction in size suggests that there is plenty of scope for yet more deletions.

Ussery, David W

2006-01-01

196

Engineering ethanologenic Escherichia coli for levoglucosan utilization  

Microsoft Academic Search

Levoglucosan is a major product of biomass pyrolysis. While this pyrolyzed biomass, also known as bio-oil, contains sugars that are an attractive fermentation substrate, commonly-used biocatalysts, such as Escherichia coli, lack the ability to metabolize this anhydrosugar. It has previously been shown that recombinant expression of the levoglucosan kinase enzyme enables use of levoglucosan as carbon and energy source. Here,

Donovan S. Layton; Avanthi Ajjarapu; Dong Won Choi; Laura R. Jarboe

2011-01-01

197

A possible osmodependent protease in Escherichia coli.  

PubMed

When a strain of Escherichia coli, expressing a hybrid protein GalK-beta-Gal, is shifted to high osmolarity, the beta-galactosidase activity strongly decreases within 20 min of shock. The loss of beta-galactosidase activity results from degradation of the hybrid protein under osmotic stress. The results raise the possibility that osmotic stress induces a specific osmodependent protease. PMID:8181701

Meury, J

1994-03-01

198

Investigation of 'Escherichia coli' Enterotoxins.  

National Technical Information Service (NTIS)

The results of the present investigation indicate a new approach to the development of a single vaccine formula which may ultimately be used to confer protection against both cholera and E. coli diarrheal disease in man and domestic animals. Fundamentally...

R. Rappaport

1978-01-01

199

Ecology of Intestinal Escherichia coli in Pigs  

PubMed Central

The coliflora of three groups of young pigs was shown to be dominated by a small number of Escherichia coli types, as determined by their O antigen, that maintained a tenure of several days or weeks. The pattern of successive waves of E. coli was similar in littermates but, in general, each pig harboured a unique sequence of E. coli types. The E. coli flora from a litter was also shown to be dominated by a small number of E. coli types whose tenure averaged several weeks. A limited amount of information indicated that an enteropathogenic strain of E. coli may occur in this sequence of events and thus appears to be influenced by the same factors as other E. coli strains. The coliflora of two sows appeared to be more complex than those of their progeny and did not seem to follow the same pattern of population change. The coliflora of young pigs differed from the coliflora of man in that there appeared to be no E. coli strains in pigs fitting the description of resident strains. Forty-two percent of all isolates were found to produce colicins and it appeared that this property was more commonly encountered in dominant strains of E. coli

Craven, J. A.; Barnum, D. A.

1971-01-01

200

Survival of Escherichia coli in stormwater biofilters.  

PubMed

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. PMID:24371007

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

2014-04-01

201

Serological Cross-Reactions between 'Escherichia coli' O157 and other Species of the Genus 'Escherichia'.  

National Technical Information Service (NTIS)

The antigenic relatedness of Escherichia coli O157 and four sorbitol-negative species of the genus Escherichia was examined. Isolates of Escherichia hermannii, E. fergusonii, E. vulneris, and E. blattae were tested in the tube agglutination assay by using...

E. W. Rice, E. G. Sowers, C. H. Johnson, M. E. Dunnigan, N. A. Strockbine

1992-01-01

202

FTIR nanobiosensors for Escherichia coli detection  

PubMed Central

Summary Infections due to enterohaemorrhagic E. coli (Escherichia coli) have a low incidence but can have severe and sometimes fatal health consequences, and thus represent some of the most serious diseases due to the contamination of water and food. New, fast and simple devices that monitor these pathogens are necessary to improve the safety of our food supply chain. In this work we report on mesoporous titania thin-film substrates as sensors to detect E. coli O157:H7. Titania films treated with APTES ((3-aminopropyl)triethoxysilane) and GA (glutaraldehyde) were functionalized with specific antibodies and the absorption properties monitored. The film-based biosensors showed a detection limit for E. coli of 1 × 102 CFU/mL, constituting a simple and selective method for the effective screening of water samples.

Greppi, Gianfranco; Marongiu, Maria Laura; Roggero, Pier Paolo; Ravindranath, Sandeep P; Mauer, Lisa J; Schibeci, Nicoletta; Perria, Francesco; Piccinini, Massimo; Innocenzi, Plinio; Irudayaraj, Joseph

2012-01-01

203

Comparison of host response mechanisms evoked by extended spectrum beta lactamase (ESBL)- and non-ESBL-producing uropathogenic E. coli  

PubMed Central

Background Infections caused by extended spectrum beta-lactamases (ESBL)-producing bacteria have been emerging worldwide and the majority of ESBL-producing E. coli strains are isolated from patients with urinary tracts infections. The purpose of this study was to compare the host-response mechanisms in human polymorphonucleated leukocytes (PMN) and renal epithelial cells when stimulated by ESBL- or non-ESBL-producing uropathogenic E. coli (UPEC) isolates. The host-pathogen interaction of these ESBL-producing strains in the urinary tract is not well studied. Results The ability of ESBL strains to evoke ROS-production from PMN cells was significantly higher than that of the non-ESBL strains. The growth of ESBL strains was slightly suppressed in the presence of PMN compared to non-ESBL strains after 30 min and 2 h, but the opposite was observed after 5 and 6 h. The number of migrating PMN was significantly higher in response to ESBL strains compared to non-ESBL strains. Stimulation of A498 cells with ESBL strains elicited lower production of IL-6 and IL-8 compared to non-ESBL strains. Conclusion Significant differences in host-response mechanisms were identified when host cells were stimulated by ESBL- or non-ESBL producing strains. The obtained results on the early interactions of ESBL-producing strains with the host immune system may provide valuable information for management of these infections.

2013-01-01

204

Studies of Escherichia coli Infection in Chickens  

PubMed Central

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.

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

1974-01-01

205

Shiga toxin-producing Escherichia coli (STEC).  

PubMed

Shiga toxin-producing Escherichia coli (STEC) are important enteric pathogens worldwide, causing diarrhea with or without blood visibly present and hemolytic uremic syndrome. STEC are unique among diarrheogenic E coli in producing Shiga toxin type 1 and type 2, the virulence factors responsible for bloody diarrhea and hemolytic uremic syndrome. Cattle and other ruminants are the natural reservoir of STEC as their normal intestinal flora. Humans become infected by consumption of foods contaminated with cattle feces. Early diagnosis of STEC infection is important because of the contraindication for treating STEC using antimicrobial agents, and the intense supportive care needed if renal failure occurs. PMID:20513540

Hunt, John M

2010-03-01

206

Hydrogen production by recombinant Escherichia coli strains  

PubMed Central

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.

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

2012-01-01

207

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

PubMed Central

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.

Brumbaugh, Ariel R; Mobley, Harry LT

2012-01-01

208

Quorum sensing in Escherichia coli and Salmonella  

Microsoft Academic Search

Quorum sensing in Escherichia coli and Salmonella has been an elusive topic for a long time. However, in the past 8 years, several research groups have demonstrated that these bacteria use several quorum-sensing systems, such as: the luxS\\/AI-2, AI-3\\/epinephrine\\/norepinephrine, indole, and the LuxR homolog SdiA to achieve intercellular signaling. The majority of these signaling systems are involved in interspecies communication,

Matthew Walters; Vanessa Sperandio

2006-01-01

209

Atypical SARS and Escherichia coli Bacteremia  

PubMed Central

We describe a patient with severe acute respiratory syndrome (SARS) whose clinical symptoms were masked by Escherichia coli bacteremia. SARS developed in a cluster of healthcare workers who had contact with this patient. SARS was diagnosed when a chest infiltrate developed and when the patient’s brother was hospitalized with acute respiratory failure. We highlight problems in atypical cases and offer infection control suggestions.

Tan, Ban Hock; Kurup, Asok; Oon, Lynette Lin Ean; Heng, Derrick; Thoe, Su Yun Se; Bai, Xin Lai; Chan, Kwai Peng; Ling, Ai Ee

2004-01-01

210

ppGpp cycle in Escherichia coli  

Microsoft Academic Search

Kinetics of accumulation and degradation of ppGpp and pppGpp were analysed in spoT+ and spoT strains of Escherichia coli. The experimental data in this paper indicate that on degradation ppGpp is not converted to pppGpp but instead is converted to GDP which is in turn phosphorylated to GTP. In addition the data are consistent with the idea the pppGpp is

Csaba Kari; István Török; Andrew Travers

1977-01-01

211

The antibacterial effect of nitric oxide against ESBL-producing uropathogenic E. coli is improved by combination with miconazole and polymyxin B nonapeptide  

PubMed Central

Background Nitric oxide (NO) is produced as part of the host immune response to bacterial infections, including urinary tract infections. The enzyme flavohemoglobin, coded by the hmp gene, is involved in protecting bacterial cells from the toxic effects of NO and represents a potentially interesting target for development of novel treatment concepts against resistant uropathogenic bacteria. The aim of the present study was to investigate if the in vitro antibacterial effects of NO can be enhanced by pharmacological modulation of the enzyme flavohemoglobin. Results Four clinical isolates of multidrug-resistant extended-spectrum ?-lactamase (ESBL)-producing uropathogenic E. coli were included in the study. It was shown that the NO-donor substance DETA/NO, but not inactivated DETA/NO, caused an initial growth inhibition with regrowth noted after 8?h of exposure. An hmp-deficient strain showed a prolonged growth inhibition in response to DETA/NO compared to the wild type. The imidazole antibiotic miconazole, that has been shown to inhibit bacterial flavohemoglobin activity, prolonged the DETA/NO-evoked growth inhibition. When miconazole was combined with polymyxin B nonapeptide (PMBN), in order to increase the bacterial wall permeability, DETA/NO caused a prolonged bacteriostatic response that lasted for up to 24?h. Conclusion An NO-donor in combination with miconazole and PMBN showed enhanced antimicrobial effects and proved effective against multidrug-resistant ESBL-producing uropathogenic E. coli.

2014-01-01

212

Prevalence of autotransporters in Escherichia coli: what is the impact of phylogeny and pathotype?  

PubMed

Autotransporter (AT) proteins are widespread surface-exposed or secreted factors in Escherichia coli. Several ATs have been correlated with pathogenesis or specific phylogenetic lineages. Therefore, an application as biomarkers for individual extraintestinal pathogenic E.coli (ExPEC) or intestinal pathogenic E.coli (IPEC) has been proposed. To put this assumption on a solid foundation, we analyzed 111 publicly available E. coli genome sequences and screened them bioinformatically for the presence of 18 ATs. We determined the highest AT prevalence per strain in phylogroup B2 isolates and showed that AT distribution correlates rather with phylogenetic lineages than with pathotypes. Although a strict dependence between AT prevalence and pathotype was not observed, EspP, EhaA, and EhaG cluster with IPEC of phylogroup B1 and E, respectively, whereas UpaH is predominantly present in ExPEC of phylogroup B2. Furthermore, PicU, SepA, UpaB, UpaI, and UpaJ were associated with phylogroup B2. We detected UpaI and its positional ortholog EhaC in 93% of the E.coli strains tested. This AT variant is thus the most prevalent in E.coli irrespective of pathotype or phylogenetic background. Compared with the ATs UpaB, UpaC, and UpaJ of uropathogenic E.coli strain 536, UpaI had redundant functions, contributing to autoaggregation, biofilm formation, and binding to extracellular matrix proteins. The functional redundancy and wide distribution of ATs among pathogenic and non-pathogenic E.coli indicates that ATs cannot generally be regarded as specific biomarkers and virulence factors. Our results demonstrate that phylogeny has a bigger impact on the distribution of AT variants in E.coli than initially thought, especially in ExPEC. PMID:24239047

Zude, Ingmar; Leimbach, Andreas; Dobrindt, Ulrich

2014-05-01

213

Frequency-Dependent Escherichia coli Chemotaxis Behavior  

NASA Astrophysics Data System (ADS)

We study Escherichia coli chemotaxis behavior in environments with spatially and temporally varying attractant sources by developing a unique microfluidic system. Our measurements reveal a frequency-dependent chemotaxis behavior. At low frequency, the E. coli population oscillates in synchrony with the attractant. In contrast, in fast-changing environments, the population response becomes smaller and out of phase with the attractant waveform. These observations are inconsistent with the well-known Keller-Segel chemotaxis equation. A new continuum model is proposed to describe the population level behavior of E. coli chemotaxis based on the underlying pathway dynamics. With the inclusion of a finite adaptation time and an attractant consumption rate, our model successfully explains the microfluidic experiments at different stimulus frequencies.

Zhu, Xuejun; Si, Guangwei; Deng, Nianpei; Ouyang, Qi; Wu, Tailin; He, Zhuoran; Jiang, Lili; Luo, Chunxiong; Tu, Yuhai

2012-03-01

214

Cloning of Beneckea genes in Escherichia coli.  

PubMed

Genes from Beneckea harveyi, a luminescent marine bacterium, were cloned in Escherichia coli. This was done by producing randomly sheared fragments of Beneckea DNA and inserting them into the EcoRI site of plasmid pMB9 by the adenine-thymine joining procedure. The hybrid plasmids were used to transform E. coli C600 SF8. Among the transformants selected for tetracycline resistance, one clone that appeared to complement a leucine tb mutation was identified. The transformants were screened for the presence of Beneckea 5S genes. Four of these clones were analyzed in detail by hybridization with 16S, 23S, and 4S Beneckea RNA. The observations suggest that the ribosomal genes in Beneckea are linked, but are present in a different order than those in E. coli. PMID:338587

Lamfrom, H; Sarabhai, A; Abelson, J

1978-01-01

215

Thymineless Death in Escherichia coli: Strain Specificity  

PubMed Central

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

Cummings, Donald J.; Mondale, Lee

1967-01-01

216

Inhibition of uropathogens by lactic acid bacteria isolated from dairy foods and cow's intestine in western Nigeria.  

PubMed

A total of 96 lactic acid bacteria (LAB) were isolated from African indigenous fermented products and cow's intestines to study their inhibitory capability against multi-drug-resistant uropathogens. Escherichia coli accounted for approximately 45% of isolated uropathogens, followed by Staphylococcus spp. (20%). The Gram negative uropathogens were highly resistant to quinolones, co-trimoxazole, teicoplanin and some beta-lactams, while the Staphylococcus spp. showed high resistance to aminoglycosides, beta-lactams and macrolides. Twenty-four LAB isolates were selected based on their antimicrobial activity against two uropathogenic Staphylococcus aureus strains and bacteriocin production. LAB strains showing antimicrobial activity were grouped into smaller groups through amplified ribosomal DNA restriction analysis (ARDRA). Representative strains were identified as Weissella spp., Enterococcus faecium, Lactococcus lactis and Lactobacillus brevis through sequencing of 16S rDNA. The Weissella spp. and L. brevis strains demonstrated remarkable inhibitory activity against seven strains of Gram negative uropathogens. Two strains of L. lactis produced a bacteriocin-like inhibitory substance active against Lactobacillus sakei. In this study, an unusual high rate of co-trimoxazole, quinolones and macrolides resistance among uropathogens from south west Nigeria was discovered. Based on their sensitivity to Weissella spp., there is a potential for using these LAB as a natural approach for the protection against the uropathogens assayed. PMID:19529917

Ayeni, Funmilola A; Adeniyi, Bolanle A; Ogunbanwo, Samuel T; Tabasco, Raquel; Paarup, Torsten; Peláez, Carmen; Requena, Teresa

2009-08-01

217

Biodegradation of Aromatic Compounds by Escherichia coli  

PubMed Central

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.

Diaz, Eduardo; Ferrandez, Abel; Prieto, Maria A.; Garcia, Jose L.

2001-01-01

218

Analysis of the Genome Structure of the Nonpathogenic Probiotic Escherichia coli Strain Nissle 1917  

PubMed Central

Nonpathogenic Escherichia coli strain Nissle 1917 (O6:K5:H1) is used as a probiotic agent in medicine, mainly for the treatment of various gastroenterological diseases. To gain insight on the genetic level into its properties of colonization and commensalism, this strain's genome structure has been analyzed by three approaches: (i) sequence context screening of tRNA genes as a potential indication of chromosomal integration of horizontally acquired DNA, (ii) sequence analysis of 280 kb of genomic islands (GEIs) coding for important fitness factors, and (iii) comparison of Nissle 1917 genome content with that of other E. coli strains by DNA-DNA hybridization. PCR-based screening of 324 nonpathogenic and pathogenic E. coli isolates of different origins revealed that some chromosomal regions are frequently detectable in nonpathogenic E. coli and also among extraintestinal and intestinal pathogenic strains. Many known fitness factor determinants of strain Nissle 1917 are localized on four GEIs which have been partially sequenced and analyzed. Comparison of these data with the available knowledge of the genome structure of E. coli K-12 strain MG1655 and of uropathogenic E. coli O6 strains CFT073 and 536 revealed structural similarities on the genomic level, especially between the E. coli O6 strains. The lack of defined virulence factors (i.e., alpha-hemolysin, P-fimbrial adhesins, and the semirough lipopolysaccharide phenotype) combined with the expression of fitness factors such as microcins, different iron uptake systems, adhesins, and proteases, which may support its survival and successful colonization of the human gut, most likely contributes to the probiotic character of E. coli strain Nissle 1917.

Grozdanov, Lubomir; Raasch, Carsten; Schulze, Jurgen; Sonnenborn, Ulrich; Gottschalk, Gerhard; Hacker, Jorg; Dobrindt, Ulrich

2004-01-01

219

ENERGY OF MAINTENANCE IN ESCHERICHIA COLI  

PubMed Central

McGrew, Sarah B. (Pennsylvania State University, University Park) and M. F. Mallette. Energy of maintenance in Escherichia coli. J. Bacteriol. 83:844–850. 1962.—Relatively dense populations of Escherichia coli B in log phase were used to detect utilization of exogenous glucose for maintenance without growth. Turbidity at 400 m? was used as the measure of growth, since it should reflect changes in either cell number or size. A threshold level of glucose was observed below which turbidity did not change during short-time experiments. Repeated additions of glucose during prolonged incubation at 37 C either increased the turbidity slowly or maintained it, depending on the amount of glucose. Plate counts to follow viability showed slow decreases for 10 days, while the unfed controls lost viability quite rapidly. From these results it was concluded that E. coli specifically utilized exogenous glucose for maintenance, without growth. The conflict of this opinion with that of earlier workers is discussed and some implications suggested.

McGrew, Sarah B.; Mallette, M. F.

1962-01-01

220

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...

221

Shear-enhanced binding of intestinal colonization factor antigen I of enterotoxigenic Escherichia coli  

PubMed Central

SUMMARY In the intestine, enterotoxigenic Escherichia coli works against peristaltic forces, adhering to the epithelium via the CFA/I fimbrial adhesin CfaE. The CfaE adhesin is similar in localization and tertiary (but not primary) structure to FimH, the type 1 fimbrial adhesin of uropathogenic Escherichia coli, which shows shear-dependent binding to epithelial receptors by an allosteric catch-bond mechanism. Thus, we speculated that CfaE is also capable of shear-enhanced binding. Indeed, bovine erythrocytes coursing over immobilized CFA/I fimbriae in flow-chambers exhibited low accumulation levels and fast rolling at low shear, but an 80-fold increase in accumulation and 3-fold decrease in rolling velocity at elevated shear. This effect was reversible and abolished by pre-incubation of fimbriae with anti-CfaE antibody. Erythrocytes bound to whole CfaE in the same shear-enhanced manner, but to CfaE adhesin domain in a shear-inhibitable fashion. Residue replacements designed to disrupt CfaE interdomain interaction decreased the shear-dependency of adhesion and increased binding under static conditions to human intestinal epithelial cells. These findings indicate that close interaction between adhesive and anchoring pilin domains of CfaE keeps the former in a low-affinity state that toggles into a high-affinity state upon separation of two domains, all consistent with an allosteric catch-bond mechanism of CfaE binding.

Tchesnokova, Veronika; McVeigh, Annette L.; Kidd, Brian; Yakovenko, Olga; Thomas, Wendy E.; Sokurenko, Evgeni V.; Savarino, Stephen J.

2010-01-01

222

Acid tolerance of enterohemorrhagic Escherichia coli.  

PubMed Central

Enterohemorrhagic Escherichia coli (EHEC) strains were tested for their ability to survive in acid pH at 37 degrees C. No loss of viability was observed in an O157:H7 EHEC strain (ATCC 43895) at pH levels of 3.0 and 2.5 for at least 5 h. The level of acid tolerance of most EHEC isolates was very high, similar to that of Shigella flexneri strains. The acid tolerance was dependent on the growth phase and pH of the growth medium.

Benjamin, M M; Datta, A R

1995-01-01

223

S-Nitrosylation Signaling in Escherichia coli  

NSDL National Science Digital Library

Most bacteria generate nitric oxide (NO) either aerobically by NO synthases or anaerobically from nitrite. Far from being a mere by-product of nitrate respiration, bacterial NO has diverse physiological roles. Many proteins undergo NO-mediated posttranslational modification (S-nitrosylation) in anaerobically grown Escherichia coli. The regulation of one such protein, OxyR, represents a redox signaling paradigm in which the same transcription factor controls different protective genes depending on its S-nitrosylation versus S-oxidation status. We discuss a structural model that may explain the remarkable stability and specificity of OxyR S-nitrosylation.

Ivan Gusarov (New York University School of Medicine;Department of Biochemistry and Molecular Pharmacology REV); Evgeny Nudler (New York University School of Medicine;Department of Biochemistry and Molecular Pharmacology REV)

2012-06-12

224

Engineering ethanologenic Escherichia coli for levoglucosan utilization.  

PubMed

Levoglucosan is a major product of biomass pyrolysis. While this pyrolyzed biomass, also known as bio-oil, contains sugars that are an attractive fermentation substrate, commonly-used biocatalysts, such as Escherichia coli, lack the ability to metabolize this anhydrosugar. It has previously been shown that recombinant expression of the levoglucosan kinase enzyme enables use of levoglucosan as carbon and energy source. Here, ethanologenic E. coli KO11 was engineered for levoglucosan utilization by recombinant expression of levoglucosan kinase from Lipomyces starkeyi. Our engineering strategy uses a codon-optimized gene that has been chromosomally integrated within the pyruvate to ethanol (PET) operon and does not require additional antibiotics or inducers. Not only does this engineered strain use levoglucosan as sole carbon source, but it also ferments levoglucosan to ethanol. This work demonstrates that existing biocatalysts can be easily modified for levoglucosan utilization. PMID:21719279

Layton, Donovan S; Ajjarapu, Avanthi; Choi, Dong Won; Jarboe, Laura R

2011-09-01

225

Engineering the Escherichia coli Fermentative Metabolism  

NASA Astrophysics Data System (ADS)

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.

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

226

Pathogenesis of adherent-invasive Escherichia coli.  

PubMed

The etiology of Crohn's disease (CD) is complex and involves both host susceptibility factors (i.e., the presence of particular genetic alleles) and environmental factors, including bacteria. In this regard, adherent-invasive Escherichia coli (AIEC), have recently emerged as an exciting potential etiological agent of CD. AIEC are distinguished from commensal strains of E. coli through their ability to adhere to and invade epithelial cells and replicate in macrophages. Recent molecular analyses have identified genes required for both invasion of epithelial cells and replication in the macrophage. However, these genetic studies, in combination with recent genome sequencing projects, have revealed that the pathogenesis of this group of bacteria cannot be explained by the presence of AIEC-specific genes. In this article, we review the role of AIEC as a pathobiont in the pathology of CD. We also describe the emerging link between AIEC and autophagy, and we propose a model for AIEC pathogenesis. PMID:24059919

Smith, Emma J; Thompson, Aoife P; O'Driscoll, Adam; Clarke, David J

2013-10-01

227

Escherichia coli growth under modeled reduced gravity  

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

228

Pandemic lineages of extraintestinal pathogenic Escherichia coli.  

PubMed

Pathogenic Escherichia coli strains cause a wide variety of intestinal and extraintestinal infections. The widespread geographical clonal dissemination of intestinal pathogenic E. coli strains, such as E. coli O157:H7, is well recognized, and its spread is most often attributed to contaminated food products. On the other hand, the clonal dissemination of extraintestinal pathogenic E. coli (ExPEC) strains is also recognized, but the mechanism of their spread is not well explained. Here, I describe major pandemic clonal lineages of ExPEC based on multilocus sequence typing (MLST), and discuss possible reasons for their global dissemination. These lineages include sequence type (ST)131, ST393, ST69, ST95, and ST73, which are all associated with both community-onset and healthcare-associated infections, in particular urinary tract infections and bloodstream infections. As with many other types of drug-resistant Gram-negative and Gram-positive bacterial infections, drug-resistant ExPEC infections are recognized to be caused by a limited set of clonal lineages. However, reported observations on these major pandemic lineages suggest that the resistance phenotype is not necessarily the determinant of their clonal dissemination. Both epidemiological factors and their intrinsic biological 'fitness' are likely to contribute. An important public health and clinical concern is that pandemicity itself may be a determinant of progressive drug resistance acquisition by clonal lineages. New research is urgently needed to better understand the epidemiological and biological causes of ExPEC pandemicity. PMID:24766445

Riley, L W

2014-05-01

229

Escherichia coli mutants defective in dipeptidyl carboxypeptidase.  

PubMed Central

Two independent mutants of Escherichia coli deficient in dipeptidyl carboxypeptidase activity (Dep-) were isolated after mutagenesis with ethyl methanesulfonate. Mating experiments and introduction of specific episomes indicated that the responsible gene was located at approximately 27--31 min on the E. coli chromosome. The Dep- mutants differed from the parental strain in their inability to grow with N-acetylalanylalanylalanine as the sole nitrogen source. Revertants selected for growth on this substrate of the enzyme were found to have reacquired the activity. Enzyme activity was highly sensitive to inhibition by 1-(D-3-mercapto-2-methylpropanoyl)-L-proline (SQ 14225), a potent inhibitor of mammalian dipeptidyl carboxypeptidase (angiotensin-converting enzyme, peptidyl dipeptidase, EC 3.4.15.1). This compound also reduced the rate of growth of the wild type with N-acetylalanylalanylalanine but not with ammonium sulfate. A fraction of the enzyme was released into the medium by osmotic shock, indicating that its presence in the periplasmic space may account for growth with N-acetylated peptides that cannot be taken up by E. coli. In addition to providing information about the specific role of this exopeptidase in E. coli, the Dep- mutants may prove useful for delineating the regulation and cellular function of dipeptidyl carboxypeptidases in higher organisms.

Deutch, C E; Soffer, R L

1978-01-01

230

Diffuse adherence of enteropathogenic Escherichia coli strains.  

PubMed

For the identification and characterization of the factor(s) responsible for the diffuse adherence (DA) pattern of enteropathogenic Escherichia coli strains, E. coli strain 2787 isolated from a case of infantile diarrhoea was employed. A plasmid-derived 11-kb fragment was cloned into pBR322. The recombinant plasmid pIB6 was shown to confer the diffuse adherence phenotype on different E. coli K12 strains as well as pIB4, a plasmid with a 9.2-kb insert. The DNA fragment necessary for the expression of the DA phenotype could be reduced to 6.0 kb. Antiserum obtained against pIB4-encoded proteins recognized a surface-associated protein of about 100 kDa in Western blotting. The isolated 100-kDa protein was found to bind to HeLa cells. The antiserum against C600(pIB4) inhibits adherence of E. coli 2787 and C600(pIB6) to HeLa cells. For this reason, the protein is called adhesin involved in diffuse adherence (AIDA-I). PMID:2101469

Benz, I; Schmidt, M A

1990-01-01

231

Cell Shape Dynamics in Escherichia coli  

PubMed Central

Bacteria are the simplest living organisms. In particular, Escherichia coli has been extensively studied and it has become one of the standard model systems in microbiology. However, optical microscopy studies of single E. coli have been limited by its small size, ?1 × 3 ?m, not much larger than the optical resolution, ?0.25 ?m. As a result, not enough quantitative dynamical information on the life cycle of single E. coli is presently available. We suggest that, by careful analysis of images from phase contrast and fluorescence time-lapse microscopy, this limitation can be bypassed. For example, we show that applying this approach to monitoring morphogenesis in individual E. coli leads to a simple, quantitative description of this process. First, we find the time when the formation of the septum starts, ?c. It occurs much earlier than the time when the constriction can be directly observed by phase contrast. Second, we find that the growth law of single cells is more likely bilinear/trilinear than exponential. This is further supported by the relations that hold between the corresponding growth rates. These methods could be further extended to study the dynamics of cell components, e.g., the nucleoid and the Z-ring.

Reshes, Galina; Vanounou, Sharon; Fishov, Itzhak; Feingold, Mario

2008-01-01

232

A multiplex PCR method to detect 14 Escherichia coli serogroups associated with urinary tract infections.  

PubMed

Urinary tract infections (UTIs) are one of the most common bacterial infections and are predominantly caused by uropathogenic Escherichia coli (UPEC). E. coli strains belonging to 14 serogroups, including O1, O2, O4, O6, O7, O8, O15, O16, O18, O21, O22, O25, O75 and O83, are the most frequently detected UPEC strains in a diverse range of clinical urine specimens. In the current study, the O-antigen gene clusters of E. coli serogroups O1, O2, O18 and O75 were characterized. A multiplex PCR method based on O-antigen-specific genes was developed for the simultaneous detection of all 14 E. coli serogroups. The multiplex PCR method was shown to be highly specific and reproducible when tested against 186 E. coli and Shigella O-serogroup reference strains, 47 E. coli clinical isolates and 10 strains of other bacterial species. The sensitivity of the multiplex PCR method was analyzed and shown to detect O-antigen-specific genes in samples containing 25 ng of genomic DNA or in mock urine specimens containing 40 colony-forming units (CFUs) per ml. Five urine specimens from hospital were examined using this multiplex PCR method, and the result for one sample was verified by the conventional serotyping methods. The multiplex PCR method developed herein can be used for the detection of relevant E. coli strains from clinical and/or environmental samples, and it is particularly useful for epidemiologic analysis of urine specimens from patients with UTIs. PMID:20434495

Li, Dan; Liu, Bin; Chen, Min; Guo, Dan; Guo, Xi; Liu, Fenxia; Feng, Lu; Wang, Lei

2010-07-01

233

DNA probe for detection of serogroup 0157 enterohemorrhagic Escherichia coli  

Microsoft Academic Search

To develop a probe for the detection of serogroup O157 enterohemorrhagic Escherichia coli (EHEC), plasmid DNA extracts from 16 E. coli strains that hybridized with the CVD419 probe were screened for restriction fragments present in plasmids of serogroup O157 E. coli strains, but not in plasmids of non-O157 E. coli strains. Using a single O157:H7 E. coli strain (6391), 10

Leslie G. Huck; C. Richard Dorn; Elisabeth J. Angrick

1995-01-01

234

Nonlethal adherence to human neutrophils mediated by Dr antigen-specific adhesins of Escherichia coli.  

PubMed Central

Uropathogenic Escherichia coli strains express a variety of adhesins, including members of the Dr adhesin family such as the Dr hemagglutinin, AFAI, and AFAIII. Certain E. coli adhesins (e.g., type 1 and S fimbriae) are known to mediate adherence to human polymorphonuclear leukocytes (PMNs). The receptor on erythrocytes for Dr family adhesins, decay accelerating factor, is also present on PMNs. To determine whether Dr family adhesins mediate adherence to PMNs and to characterize the specificity and consequences of such adherence, we studied agglutination of PMNs and adherence to PMNs by recombinant E. coli strains expressing various mannose-resistant or mannose-sensitive adhesins, in the presence or absence of inhibitors of adherence. Dr family adhesins, like type 1 fimbriae, mediated concentration-dependent adherence to PMNs. Adherence to PMNs was mannose sensitive for type 1 fimbriae but mannose resistant for Dr family adhesins. Chloramphenicol inhibited PMN adherence for the Dr hemagglutinin with the same potency as that with which it inhibited hemagglutination, but it was inactive against PMN adherence and hemagglutination mediated by other members of the Dr adhesin family. In contrast to PMN adherence mediated by type 1 fimbriae, adherence mediated by the Dr hemagglutinin did not lead to significantly increased bacterial killing. These data suggest that Dr family adhesins mediate a novel pattern of adherence to PMNs, probably by recognizing decay accelerating factor, with minimal consequent bacterial killing.

Johnson, J R; Skubitz, K M; Nowicki, B J; Jacques-Palaz, K; Rakita, R M

1995-01-01

235

Chemoreceptors of Escherichia coli CFT073 play redundant roles in chemotaxis toward urine.  

PubMed

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. PMID:23382874

Raterman, Erica L; Welch, Rodney A

2013-01-01

236

Role of Escherichia coli P fimbriae in intestinal colonization in gnotobiotic rats.  

PubMed Central

Adherence via P fimbriae is associated with long-term persistence of Escherichia coli in the human large intestine, but a causal relationship has not been proven. In the present study, germfree rats were colonized with a mixture of two isogenic E. coli strains, one P fimbriated and the other type 1 fimbriated. Both types of fimbriae conferred adherence to rat colonic epithelial cells. With two mutant strains from a pyelonephritogenic isolate of serotype O75:K5:H-, the P-fimbriated strain 824 attained much higher numbers than its type 1-fimbriated counterpart when colonized in vivo for 2 weeks (10(10) versus 10(6) bacteria per g, respectively; P < 0.0001). The expression of P fimbriae by 824 was also retained during colonization. With transformant isogenic strains obtained from a normal fecal isolate incapable of phase variation, no benefit of P fimbriae was seen and most bacteria lost their plasmids during in vivo colonization. When the pyelonephritogenic mutant and fecal transformant strains were combined, the former colonized at high levels while the latter were suppressed. In contrast, no suppression was seen when the transformant E. coli strains colonized in combination with Lactobacillus acidophilus or Peptostreptococcus sp. The results indicate that P fimbriae, but also other bacterial traits linked to uropathogeneicity, could play an important role for persistence in the gut normal microbiota. Neither P nor type 1 fimbriae seemed to contribute to the ability to translocate to the mesenteric lymph nodes.

Herias, M V; Midtvedt, T; Hanson, L A; Wold, A E

1995-01-01

237

Production of glycoprotein vaccines in Escherichia coli  

PubMed Central

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 production of conjugate vaccines, which in future may be used for combating severe infectious diseases, particularly in developing countries.

2010-01-01

238

Genotype comparison of sorbitol-negative Escherichia coli isolates from healthy broiler chickens from different commercial farms.  

PubMed

Hybridization on arrays was used to assess the presence of virulence-associated genes and to determine the relatedness of 32 non-O157 sorbitol-negative Escherichia coli isolates from healthy broiler chickens. These isolates were from commercial farms that used feed supplemented with different antimicrobial agents (virginiamycin, bacitracin, salinomycin, narasin, nicarbazin, or diclazuril). For each isolate, fluorescent probes were made from genomic DNA and were hybridized on DNA arrays composed of genes associated with general functions, virulence, iron uptake systems, and DNA repair genes (e.g., mut genes). Hybridization on arrays results showed that isolates from the same farm tended to be clustered but actually represented 18 genetically distinct groups of isolates. Results revealed that some isolates showed similarity to human uropathogenic E. coli or avian pathogenic E. coli. Four avian pathogenic E. coli-like isolates were detected. Another isolate possessed the intimin gene (eaeA) and typical genes of the type 3 secretion system associated with enteropathogenic E. coli and enterohemorrhagic E. coli strains. Genes from a second system (secondary type 3 secretion system) homologous to that found in Salmonella Typhimurium were detected in many isolates. Several of the studied isolates also possessed the aerobactin, salmochelin, and yersiniabactin genes involved in iron acquisition in pathogenic bacteria. Our results clearly suggest that commensal E. coli isolates from chickens are reservoirs of virulence-associated genes and may represent colibacillosis and zoonotic risks. PMID:19531720

Lefebvre, B; Gattuso, M; Moisan, H; Malouin, F; Diarra, M S

2009-07-01

239

Regulation of alcohol fermentation by Escherichia coli  

SciTech Connect

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.

Clark, D.P.

1990-01-01

240

Long term effects of Escherichia coli mastitis.  

PubMed

Escherichia coli is one of the most frequently diagnosed causes of bovine mastitis, and is typically associated with acute, clinical mastitis. The objective of the present study was to evaluate the long term effects of intramammary infections by E. coli on milk yield and quality, especially milk coagulation. Twenty-four Israeli Holstein cows diagnosed with clinical mastitis due to intramammary infection by E. coli were used in this study. Mean lactation number, days in milk (DIM) and daily milk yield (DMY) at the time of infection was 3.3?±?1.3, 131.7 days?±?78.6 and 45.7?L?±?8.4, respectively. DMY, milk constituents, somatic cells count (SCC), differential leukocytes count and coagulation parameters were subsequently assessed. Two patterns of inflammation were identified: 'short inflammation', characterized by <15% decrease in DMY and <30 days until return to normal (n?=?5), and 'long inflammation', characterized by >15% decrease in DMY and >30 days to reach a new maximum DMY (n?=?19). The estimated mean loss of marketable milk during the study was 200?L/cow for 'short inflammation' cases, and 1500?L/cow for 'long inflammation' ones. Significant differences between 'short' and 'long inflammation' effects were found in almost all parameters studied. Long-term detrimental effects on milk quality were found regardless of clinical or bacteriological cure of affected glands. PMID:24906501

Blum, Shlomo E; Heller, Elimelech D; Leitner, Gabriel

2014-07-01

241

Characterization of enteroaggregative Escherichia coli isolates.  

PubMed

Forty enteraggregative Escherichia coli (EAggEC) previously characterized by their ability to adhere to HEp-2 cells or/and their hybridization with the 1-kb EAggEC DNA probe were investigated for the presence of adherence factors and heat-stable enterotoxin (EAST1)-encoding genes. Only 45% of the isolates harbored the EAST1-encoding genes as detected by polymerase chain reaction. None of them hybridized with an AAF/II-encoding gene specific DNA probe and 35% (14/40) were positive in a PCR assay using primers specific for aggC, an accessory gene of the AAF/I-encoding operon. Cloning and sequence analysis of the aggA variant from one isolate, EAggEC 457, revealed 68.9% identity between its deduced amino acid sequence and those of the aggA product from the AAF/I-producing reference strain, E. coli 17.2. No major protein subunit was detected at the surface of EAggEC 457 compared to the bacterial surface extract of E. coli 17.2. PMID:10220881

Rich, C; Favre-Bonte, S; Sapena, F; Joly, B; Forestier, C

1999-04-01

242

STUDIES ON THE LACTASE OF ESCHERICHIA COLI  

PubMed Central

A "lactase solution" was prepared from Escherichia coli. The mechanism of its action has been studied and changes in the rate of hydrolysis under various conditions investigated. The hydrolysis of lactose by the enzyme approximates the course of reaction of the integrated Michaelis-Menten equation. One molecule of enzyme combines with one molecule of substrate. E. coli lactase is readily inactivated at pH 5.0, and its optimal activity at 36°C. is reached between pH 7.0 and pH 7.5. The optimal temperature for its action was found to be 46°C. when determinations were carried out after an incubation period of 30 minutes. Its inactivation by heat follows the course of a first order reaction, and the critical thermal increment between the temperatures of 45°C. and 53°C. was calculated to be 56,400 calories per mol. The enzyme is activated by potassium cyanide, sodium sulfide, and cysteine, and irreversibly inactivated by mercuric chloride, silver nitrate, and iodine. After inactivation with copper sulfate partial reactivation is possible, while the slight inhibition brought about by hydrogen peroxide is completely reversible. The possible structure of the active groups of E. coli lactase as compared with other enzymes has been discussed.

Knopfmacher, H. P.; Salle, A. J.

1941-01-01

243

Prevalence and risk factor analysis of resistant Escherichia coli urinary tract infections in the emergency department  

PubMed Central

Background Escherichia coli (E. coli) is a frequent uropathogen in urinary tract infections (UTI). Widespread resistance to sulfamethoxazole-trimethoprim (SMX-TMP) and increasing resistance to fluoroquinolones amongst these isolates has been recognized. There are limited data demonstrating risk factors for resistance to both SMX-TMP and fluoroquinolones. Objective This study was conducted to assess for the prevalence of community resistance amongst E. coli isolates to SMX-TMP and levofloxacin in ambulatory patients discharged from the emergency department (ED). Methods Adults presenting for evaluation and discharged from the ED with a diagnosis of an E. coli UTI were retrospectively reviewed. Utilizing demographic and clinical data the prevalence of E. coli resistance and risk factors associated with SMX-TMP- and fluoroquinolone-resistant infection were determined. Results Among the 222 patients, the mean rates of E. coli susceptibility to levofloxacin and SMX-TMP were 82.4% and 72.5%, respectively. Significant risk factors for resistance to SMX-TMP included prior antibiotic use (p=0.04) and prior diagnosis of UTI (p= 0.01). Significant risk factors for resistance to levofloxacin included: male gender, age, presence of hypertension, diabetes, chronic respiratory disease, nursing home resident, previous antibiotic use, previous diagnosis of UTI, existence of renal or genitourinary abnormalities, and prior surgical procedures (p <0.05 for all comparisons). The number of hospital days prior to initial ED evaluation (p<0.001) was determined to be a predictive factor in hospital and ED readmission. Conclusions These results suggest that conventional approaches to monitoring for patterns of susceptibility may be inadequate. It is imperative that practitioners develop novel approaches to identifying patients with risk factors for resistance. Identification of risk factors from this evaluation should prompt providers to scrutinize the use of these agents in the setting of patients presenting with an uncomplicated UTI in the ED.

Bailey, Abby M.; Weant, Kyle A.; Baker, Stephanie N.

244

Molecular characterisation of Escherichia coli isolated from hospitalised children and adults with urinary tract infection.  

PubMed

Urinary tract infection (UTI) is common amongst children and recurs in 10-30 % of cases. The differences between Escherichia coli strains causing UTI among hospitalised children and adults remains to be fully elucidated. Here, we examined the genetic relatedness and virulence gene (VG) profiles of a collection of E. coli causing UTI among hospitalised children and adults. Genetic relatedness among the strains was investigated using random amplified polymorphic DNA (RAPD) analysis and the strains were characterised using a combination of phylogenetic grouping, the ability to form biofilm and the presence of antigen 43 (Ag43) and its five known alleles, as well 20 VGs associated with uropathogenic E. coli (UPEC). RAPD analysis resolved six major clusters, with two clusters (A and B) consisting almost exclusively of E. coli isolated from children. Isolates from children had a higher prevalence of alpha-haemolysin (hlyA, p?coli strains from adults had a higher prevalence of invasive ibeA (p?coli from children. Adult isolates also carried significantly (p?

Vollmerhausen, T L; Katouli, M

2014-06-01

245

Molecular Evolutionary Relationships of Enteroinvasive Escherichia coli and Shigella spp  

Microsoft Academic Search

Enteroinvasive Escherichia coli (EIEC), a distinctive pathogenic form of E. coli causing dysentery, is similar in many properties to bacteria placed in the four species of Shigella. Shigella has been separated as a genus but in fact comprises several clones of E. coli. The evolutionary relationships of 32 EIEC strains of 12 serotypes have been determined by sequencing of four

Ruiting Lan; M. Chehani Alles; Kathy Donohoe; Marina B. Martinez; Peter R. Reeves

2004-01-01

246

Differentiation in virulence patterns of Escherichia coli possessing eae genes  

Microsoft Academic Search

In this study 98 Escherichia coli strains which belonged to traditional enteropathogenic (EPEC) serotypes and 82 enterohemorrhagic E. coli (EHEC) strains were screened by polymerase chain reaction (PCR) for the presence of E. coli -attaching and -effacing (eae) genes. These strains were also hybridized with the enteropathogenic adherence factor (EAF) probe and examined in the fluorescence actin staining (FAS) test.

Herbert Schmidt; Barbara Plaschke; Sylvia Franke; Holger Riissmann; Andreas Schwarzkopf; Jiirgen Heesemann; Helge Karch

1994-01-01

247

Antimicrobial activity of Nutmeg against Escherichia coli O157  

Microsoft Academic Search

We examined the difference between Escherichia coli O157 and non-pathogenic E. coli in their tolerance to spices. Various spices (5 g each) were homogenized at 25°C for 10 min with 5 ml of 70% ethyl alcohol, and the supernatant solutions obtained by centrifugation were used as spice extracts. When the E. coli strains were incubated with each spice extract at

Akiko Takikawa; Keiko Abe; Makiko Yamamoto; Shoko Ishimaru; Mari Yasui; Yoko Okubo; Kumio Yokoigawa

2002-01-01

248

Changing faecal population of escherichia coli in hospital medical patients  

PubMed Central

Specimens of faeces were obtained at weekly intervals for one year from patients in a female medical ward and Escherichia coli present were typed. The faecal E. coli population of the patients was constantly changing. No serotypes of E. coli were dominant, but on 31 occasions during the year small clusters of patients carried the same type.

Cooke, E. Mary; Ewins, Susan; Shooter, R. A.

1969-01-01

249

A-type cranberry proanthocyanidins and uropathogenic bacterial anti-adhesion activity  

Microsoft Academic Search

Clinical, epidemiological and mechanistic studies support the role of cranberry (Vaccinium macrocarpon Ait.) in maintaining urinary tract health. Cranberry proanthocyanidins contain A-type linkages and have been associated with preventing adhesion of P-fimbriated uropathogenic Escherichia coli to uroepithelial cells. It is not known if the presence of the A-type linkage is a prerequisite for anti-adhesion activity. Other commercial sources of proanthocyanidins

Amy B. Howell; Jess D. Reed; Christian G. Krueger; Ranee Winterbottom; David G. Cunningham; Marge Leahy

2005-01-01

250

Vibrio parahaemolyticus, enterotoxigenic Escherichia coli, enterohemorrhagic Escherichia coli and Vibrio cholerae  

PubMed Central

This review highlighted the following: (i) pathogenic mechanism of the thermostable direct hemolysin produced by Vibrio parahaemolyticus, especially on its cardiotoxicity, (ii) heat-labile and heat-stable enterotoxins produced by enterotoxigenic Escherichia coli, especially structure–activity relationship of heat-stable enterotoxin, (iii) RNA N-glycosidase activity of Vero toxins (VT1 and VT2) produced by enterohemorrhagic Escherichia coli O157:H7, (iv) discovery of Vibrio cholerae O139, (v) isolation of new variant of Vibrio cholerae O1 El Tor that carries classical ctxB, and production of high concentration of cholera toxin by these strains, and (vi) conversion of viable but nonculturable (VBNC) Vibrio cholerae to culturable state by co-culture with eukaryotic cells.

TAKEDA, Yoshifumi

2011-01-01

251

Escherichia coli malate dehydrogenase, a novel solubility enhancer for heterologous proteins synthesized in Escherichia coli  

Microsoft Academic Search

Using 2-dimensional gel electrophoresis, the Escherichia coli proteome response to a heat-shock stress was analyzed and a 1.6-fold increase of malate dehydrogenase was observed even under\\u000a the heat-shock condition where the total number of soluble proteins decreased by about 5%. We subsequently demonstrated that,\\u000a as an N-terminus fusion expression partner, malate dehydrogenase facilitated the folding of, and dramatically increased the

Jin-Seung Park; Kyung-Yeon Han; Jong-Am Song; Keum-Young Ahn; Hyuk-Seong Seo; Jeewon Lee

2007-01-01

252

Taurine modulates neutrophil function but potentiates uropathogenic E. coli infection in the murine bladder.  

PubMed

Eradication of a urinary tract infection (UTI) appears to be related to a number of innate host defence mechanisms and their interactions with invading bacteria. Recurrent UTIs (rUTIs) pose a difficult problem in that these bacteria use both host and bacterial factors to evade elimination. Neutrophil bactericidal function is depressed, both systemically and in urine, in patients with a history of recurrent UTI. Taurine is a semi-essential amino acid and is successful in preserving neutrophil bactericidal function in urine. Taurine may preserve neutrophil function at the urothelium and thus aid UTI resolution. Adult female (6 weeks old) C57Bl/6 mice were randomised into three groups: a saline gavage only control group, a saline gavage + E. coli group, and a taurine gavage + E. coli group [21 g/70 kg taurine in 0.9% normal saline (N/S) for 5 days]. Whilst taurine gavage pre-treatment resulted in increased serum neutrophils respiratory burst activity, at the urothelial-endothelial interface it caused higher colony forming units in the urine and a higher incidence of E. coli invasion in the bladder wall with no evidence of increased bladder wall neutrophils infiltration on MPO assay of histological assessment. Histologically there was also evidence of reduced bladder inflammation and urothelial cell apoptosis. In conclusion, taurine effectively increases neutrophils activity but given its anti-inflammatory properties, at the expense of decreased urothelial-endothelial activation thus preventing clearance of active E. coli infection in the bladder. Despite the negative results, this study demonstrates the importance of modulating interactions at the urothelial interface. PMID:19940987

Condron, Claire; Casey, Rowan G; Kehoe, Siobhan; Toomey, Deirdre; Creagh, Tom; Bouchier-Hayes, David J

2010-08-01

253

Deg phenotype of Escherichia coli lon mutants.  

PubMed Central

Deg. one of the Escherichia coli systems for degrading abnormal polypeptides (e.g., nonsense fragments), is also involved in the degradation of some classes of missense proteins. Both missense proteins of beta-galactosidase and temperature-sensitive phage products appear to be degraded by the Deg system. Mutations in the Deg system are indistinguishable from mutations classically called lon or capR; all map near proC, all are mucoid, defective in protein degradation, sensitive to radiomimetic agents, and defective in P1 lysogenization. All are able to propagate temperature-sensitive phage better than lon+ parental strains. Mutations that suppress the radiation sensitivity of these strains (sul) also suppress the P1 lysogenization defect, but do not affect mucoidy or the degradation defect.

Gottesman, S; Zipser, D

1978-01-01

254

Escherichia coli evolution during stationary phase.  

PubMed

The process of evolution by natural selection has been known for a century and a half, yet the mechanics of selection are still poorly understood. In most cases where natural selection has been studied, the genetic and physiological bases of fitness variation that result in population changes were not identified, leaving only a partial understanding of selection. Starved cultures of the bacterium Escherichia coli present a model system with which to address the genetic and physiological bases of natural selection. This is a model system that also reflects the prevalent state of bacteria in the natural world; due to intense competition for nutrients, microorganisms spend the majority of their lives under starvation conditions. Genetic analyses of a single survivor of starvation identified four adaptive mutations(1). Investigation of these mutations has revealed insights into the molecular and physiological bases of evolution during prolonged starvation stress. PMID:15207864

Zinser, Erik R; Kolter, Roberto

2004-06-01

255

Escherichia coli fliAZY operon.  

PubMed Central

We have cloned the Escherichia coli fliAZY operon, which contains the fliA gene (the alternative sigma factor sigma F) and two novel genes, fliZ and fliY. Transcriptional mapping of this operon shows two start sites, one of which is preceded by a canonical E sigma F-dependent consensus and is dependent on sigma F for expression in vivo and in vitro. We have overexpressed and purified sigma F and demonstrated that it can direct core polymerase to E sigma F-dependent promoters. FliZ and FliY are not required for motility but may regulate sigma F activity, perhaps in response to a putative cell density signal that may be detected by FliY, a member of the bacterial extracellular solute-binding protein family 3.

Mytelka, D S; Chamberlin, M J

1996-01-01

256

Eco Cyc: encyclopedia of Escherichia coli genes and metabolism  

Microsoft Academic Search

The encyclopedia of Escherichia coli genes andmetabolism (EcoCyc) is a database that combinesinformation about the genome and the intermediarymetabolism of E.coli. The database describes 3030genes of E.coli, 695 enzymes encoded by a subset ofthese genes, 595 metabolic reactions that occur inE.coli, and the organization of these reactions into 123metabolic pathways. The EcoCyc graphical user interfaceallows scientists to query and explore

Peter D. Karp; Monica Riley; Suzanne M. Paley; Alida Pellegrini-toole; Markus Krummenacker

1999-01-01

257

EcoCyc: Encyclopedia of Escherichia coli genes and metabolism  

Microsoft Academic Search

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

Peter D. Karp; Monica Riley; Suzanne M. Paley; Alida Pellegrini-toole; Markus Krummenacker

1998-01-01

258

Population structure of gut Escherichia coli and its role in development of extra-intestinal infections  

PubMed Central

Extra-intestinal pathogenic Escherichia coli (ExPEC) strains are divided into uropathogenic E. coli (UPEC), strains causing neonatal meningitis and septicaemic E. coli. The most common pathotype of ExPEC is found among patients with urinary tract infection (UTI), defined as UPEC. These bacteria are responsible for >90% of cases of UTI and are often found amongst the faecal flora of the same host. E.coli strains are classified into four phylogenetic groups, A, B1, B2, and D. Groups A and B1 are commensal strains and carry few virulence-associated genes (VGs) while pathogenic group B2 and D usually possess VGs which enhance colonic persistence and adhesion in the urinary tract (UT). The gastrointestinal (GI) tract is widely accepted as a reservoir for UPEC and is believed that healthy humans have a reservoir of UPEC strains, belonging to phylogenetic group B2, and to a lesser extent, group D. These strains have superior ability to survive and persist in the gut of humans and can spread to cause extra-intestinal infections. ExPEC trains possess a range of VGs which are involved in their pathogenesis. These include adhesins, toxins, iron-acquisition systems (e.g. siderophores), and capsules. Evolutionary influences on the acquisition and main role of VGs amongst E. coli are widely debated, with some research holding that the prevalence of strains with VGs increases the likelihood of infections, whereas others believe that VGs provide a selective advantage for infection of extra-intestinal sites. This review is intended to present our existing knowledge and gaps in this area.

Katouli, Mohammad

2010-01-01

259

Structural Sampling of Glycan Interaction Profiles Reveals Mucosal Receptors for Fimbrial Adhesins of Enterotoxigenic Escherichia coli  

PubMed Central

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, GlcNAc?1,3Gal. 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.

Lonardi, Emanuela; Moonens, Kristof; Buts, Lieven; de Boer, Arjen R.; Olsson, Johan D. M.; Weiss, Manfred S.; Fabre, Emeline; Guerardel, Yann; Deelder, Andre M.; Oscarson, Stefan; Wuhrer, Manfred; Bouckaert, Julie

2013-01-01

260

Structural Sampling of Glycan Interaction Profiles Reveals Mucosal Receptors for Fimbrial Adhesins of Enterotoxigenic Escherichia coli.  

PubMed

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

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

261

Surface expression of ?-transaminase in Escherichia coli.  

PubMed

Chiral amines are important for the chemical and pharmaceutical industries, and there is rapidly growing interest to use transaminases for their synthesis. Since the cost of the enzyme is an important factor for process economy, the use of whole-cell biocatalysts is attractive, since expensive purification and immobilization steps can be avoided. Display of the protein on the cell surface provides a possible way to reduce the mass transfer limitations of such biocatalysts. However, transaminases need to dimerize in order to become active, and furthermore, they require the cofactor pyridoxal phosphate; consequently, successful transaminase surface expression has not been reported thus far. In this work, we produced an Arthrobacter citreus ?-transaminase in Escherichia coli using a surface display vector based on the autotransporter adhesin involved in diffuse adherence (AIDA-I), which has previously been used for display of dimeric proteins. The correct localization of the transaminase in the E. coli outer membrane and its orientation toward the cell exterior were verified. Furthermore, transaminase activity was detected exclusively in the outer membrane protein fraction, showing that successful dimerization had occurred. The transaminase was found to be present in both full-length and proteolytically degraded forms. The removal of this proteolysis is considered to be the main obstacle to achieving sufficient whole-cell transaminase activity. PMID:24487538

Gustavsson, Martin; Muraleedharan, Madhu Nair; Larsson, Gen

2014-04-01

262

Rates of transposition in Escherichia coli.  

PubMed

The evolutionary role of transposable elements (TEs) is still highly controversial. Two key parameters, the transposition rate (u and w, for replicative and non-replicative transposition) and the excision rate (e) are fundamental to understanding their evolution and maintenance in populations. We have estimated u, w and e for six families of TEs (including eight members: IS1, IS2, IS3, IS4, IS5, IS30, IS150 and IS186) in Escherichia coli, using a mutation accumulation (MA) experiment. In this experiment, mutations accumulate essentially at the rate at which they appear, during a period of 80 500 (1610 generations × 50 lines) generations, and spontaneous transposition events can be detected. This differs from other experiments in which insertions accumulated under strong selective pressure or over a limited genomic target. We therefore provide new estimates for the spontaneous rates of transposition and excision in E. coli. We observed 25 transposition and three excision events in 50 MA lines, leading to overall rate estimates of u ? 1.15 × 10(-5), w ? 4 × 10(-8) and e ? 1.08 × 10(-6) (per element, per generation). Furthermore, extensive variation between elements was found, consistent with previous knowledge of the mechanisms and regulation of transposition for the different elements. PMID:24307531

Sousa, Ana; Bourgard, Catarina; Wahl, Lindi M; Gordo, Isabel

2013-12-23

263

Isobutanol production from cellobiose in Escherichia coli.  

PubMed

Converting lignocellulosics into biofuels remains a promising route for biofuel production. To facilitate strain development for specificity and productivity of cellulosic biofuel production, a user friendly Escherichia coli host was engineered to produce isobutanol, a drop-in biofuel candidate, from cellobiose. A beta-glucosidase was expressed extracellularly by either excretion into the media, or anchoring to the cell membrane. The excretion system allowed for E. coli to grow with cellobiose as a sole carbon source at rates comparable to those with glucose. The system was then combined with isobutanol production genes in three different configurations to determine whether gene arrangement affected isobutanol production. The most productive strain converted cellobiose to isobutanol in titers of 7.64?±?0.19 g/L with a productivity of 0.16 g/L/h. These results demonstrate that efficient cellobiose degradation and isobutanol production can be achieved by a single organism, and provide insight for optimization of strains for future use in a consolidated bioprocessing system for renewable production of isobutanol. PMID:24430208

Desai, Shuchi H; Rabinovitch-Deere, Christine A; Tashiro, Yohei; Atsumi, Shota

2014-04-01

264

Expanding ester biosynthesis in Escherichia coli.  

PubMed

To expand the capabilities of whole-cell biocatalysis, we have engineered Escherichia coli to produce various esters. The alcohol O-acyltransferase (ATF) class of enzyme uses acyl-CoA units for ester formation. The release of free CoA upon esterification with an alcohol provides the free energy to facilitate ester formation. The diversity of CoA molecules found in nature in combination with various alcohol biosynthetic pathways allows for the biosynthesis of a multitude of esters. Small to medium volatile esters have extensive applications in the flavor, fragrance, cosmetic, solvent, paint and coating industries. The present work enables the production of these compounds by designing several ester pathways in E. coli. The engineered pathways generated acetate esters of ethyl, propyl, isobutyl, 2-methyl-1-butyl, 3-methyl-1-butyl and 2-phenylethyl alcohols. In particular, we achieved high-level production of isobutyl acetate from glucose (17.2 g l(-1)). This strategy was expanded to realize pathways for tetradecyl acetate and several isobutyrate esters. PMID:24609358

Rodriguez, Gabriel M; Tashiro, Yohei; Atsumi, Shota

2014-04-01

265

Escherichia coli biofilm formation and recurrences of urinary tract infections in children.  

PubMed

It has been suggested that biofilm formation by uropathogenic Escherichia coli (UPEC) isolates is associated with recurrence and persistence of urinary tract infection (UTI). We compared the in vitro biofilm formation of UPEC isolates from children with acute or recurrent UTI. Employing 206 consecutive clinical UPEC isolates from children with proven UTI, i.e., pyelonephritis (n?=?78), recurrent pyelonephritis (n?=?10), cystitis (n?=?84) or recurrent cystitis (n?=?34), we applied 1 % crystal violet staining to polystyrene microtitre plates at 72 h and measured the optical density (OD) values. The method had been validated to measure biofilm formation against confocal laser scanning microscopy and scanning electron microscopy. The OD values were lower in the recurrent cystitis group than in the other groups (mean OD 0.36, SD 0.21 vs mean 0.47, SD 0.36, P?=?0.04) and higher in the recurrent pyelonephritis group than in the other groups (mean OD 0.69, SD 0.33 vs mean OD 0.44, SD 0.34, P?=?0.006) indicating biofilm formation of strains causing recurrent pyelonephritis. It appears that the properties of UPEC isolates required for effective biofilm growth on an abiotic surface are important for recurrent pyelonephritis, but not for recurrent cystitis. It would be valuable in the future to analyze whether the biofilm properties of E. coli observed in vitro predict a slower clinical response to antimicrobial treatment and increased renal scar formation after UTI. PMID:23996047

Tapiainen, T; Hanni, A-M; Salo, J; Ikäheimo, I; Uhari, M

2014-01-01

266

Selection of recently isolated colicinogenic Escherichia coli strains inhibitory to Escherichia coli O157:H7.  

PubMed

Escherichia coli strains were screened for their ability to inhibit E. coli O157:H7. An initial evaluation of 18 strains carrying previously characterized colicins determined that only colicin E7 inhibited all of the E. coli O157:H7 strains tested. A total of 540 strains that had recently been isolated from humans and nine different animal species (cats, cattle, chickens, deer, dogs, ducks, horses, pigs, and sheep) were tested by a flip-plating technique. Approximately 38% of these strains were found to inhibit noncolicinogenic E. coli K12 strains. The percentage of potentially colicinogenic E. coli per animal species ranged from 14% for horse isolates to 64% for sheep strains. Those isolates that inhibited E. coli K12 were screened against E. coli O157:H7, and 42 strains were found to be capable of inhibiting all 22 pathogenic strains tested. None of these 42 strains produced bacteriophages, and only 24 isolates inhibited serotype O157:H7 in liquid culture. The inhibitory activity of these strains was completely eliminated by treatment with proteinase K. When mixtures of these 24 colicinogenic strains were grown in anaerobic continuous culture, the four-strain E. coli O157:H7 population was reduced at a rate of 0.25 log10 cells per ml per h, which was fivefold faster than the washout rate. Two strains originally isolated from cat feces (F16) and human feces (H30) were identified by repetitive sequences polymerase chain reaction as the predominant isolates in continuous cultures. The results of this work indicate that animal species other than cattle can be sources of anti-O157 colicinogenic strains, and these results also lead to the identification of at least two isolates that could potentially be used in preharvest control strategies. PMID:12233846

Schamberger, Gerry P; Diez-Gonzalez, Francisco

2002-09-01

267

Electron Microscopy of Chloramphenicol-Treated Escherichia Coli.  

National Technical Information Service (NTIS)

Thin sections of Escherichia coli were examined by electron microscopy at sequential intervals after addition and then removal of chloramphenicol. The first changes, occurring at 1 hr after exposure to the drug, were disappearance of the ribosomes and agg...

C. Morgan H. S. Rosenkranz H. S. Carr H. M. Rose

1967-01-01

268

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...

269

Prevention of Death in Escherichia Coli (ld100) Shock.  

National Technical Information Service (NTIS)

This study was designed to determine the efficacy of maintenance infusions of methylprednisolone sodium succinate and gentamicin sulfate in live Escherichia coli organism shock. Twenty-three conditioned dogs were anesthetized, instrumented aseptically, in...

L. B. Hinshaw B. K. Beller L. T. Archer D. J. Flournoy G. L. White

1979-01-01

270

Susceptibilities of Escherichia coli and Staphylococcus aureus to Aloe barbadensis.  

PubMed

The in vitro susceptibilities of Escherichia coli and Staphylococcus aureus were evaluated and the two organisms were susceptible to the inner gel of aloe barbadensis, though it was more effective against Staphylococcus aureus than Escherichia coli. The reduction for Aloe Vera (AV) needed to suppress the growth of the gram-positive bacterium was attributed to the structural differences between the two organisms. PMID:20085127

Shilpakala, S R; Prathiba, J; Malathi, R

2009-01-01

271

Distribution of the Escherichia coli Common Pilus among Diverse Strains of Human Enterotoxigenic E. coli  

Microsoft Academic Search

The Escherichia coli common pilus (ECP) is produced by commensal and pathogenic E. coli strains. This pilus is unrelated to any of the known colonization factors (CFs) of enterotoxigenic E. coli (ETEC). In this study, we investigated the distribution and production of ECP among a collection of 136 human CF-positive and CF-negative ETEC strains of different geographic origins. The major

Dana Blackburn; Amanda Husband; Zeus Saldana; Rania A. Nada; John Klena; Firdausi Qadri; Jorge A. Giron

2009-01-01

272

Whole-genome phylogeny of Escherichia coli/Shigella group by feature frequency profiles (FFPs)  

PubMed Central

A whole-genome phylogeny of the Escherichia coli/Shigella group was constructed by using the feature frequency profile (FFP) method. This alignment-free approach uses the frequencies of l-mer features of whole genomes to infer phylogenic distances. We present two phylogenies that accentuate different aspects of E. coli/Shigella genomic evolution: (i) one based on the compositions of all possible features of length l = 24 (?8.4 million features), which are likely to reveal the phenetic grouping and relationship among the organisms and (ii) the other based on the compositions of core features with low frequency and low variability (?0.56 million features), which account for ?69% of all commonly shared features among 38 taxa examined and are likely to have genome-wide lineal evolutionary signal. Shigella appears as a single clade when all possible features are used without filtering of noncore features. However, results using core features show that Shigella consists of at least two distantly related subclades, implying that the subclades evolved into a single clade because of a high degree of convergence influenced by mobile genetic elements and niche adaptation. In both FFP trees, the basal group of the E. coli/Shigella phylogeny is the B2 phylogroup, which contains primarily uropathogenic strains, suggesting that the E. coli/Shigella ancestor was likely a facultative or opportunistic pathogen. The extant commensal strains diverged relatively late and appear to be the result of reductive evolution of genomes. We also identify clade distinguishing features and their associated genomic regions within each phylogroup. Such features may provide useful information for understanding evolution of the groups and for quick diagnostic identification of each phylogroup.

Sims, Gregory E.; Kim, Sung-Hou

2011-01-01

273

The Modular Organization of Protein Interactions in Escherichia coli  

Microsoft Academic Search

Escherichia coli serves as an excellent model for the study of fundamental cellular processes such as metabolism, signalling and gene expression. Understanding the function and organization of proteins within these processes is an important step towards a ‘systems’ view of E. coli. Integrating experimental and computational interaction data, we present a reliable network of 3,989 functional interactions between 1,941 E.

José M. Peregrín-Alvarez; Xuejian Xiong; Chong Su; John Parkinson

2009-01-01

274

Directed Evolution of Ionizing Radiation Resistance in Escherichia coli  

Microsoft Academic Search

We have generated extreme ionizing radiation resistance in a relatively sensitive bacterial species, Esche- richia coli, by directed evolution. Four populations of Escherichia coli K-12 were derived independently from strain MG1655, with each specifically adapted to survive exposure to high doses of ionizing radiation. D37 values for strains isolated from two of the populations approached that exhibited by Deinococcus radiodurans.

Dennis R. Harris; Steve V. Pollock; Elizabeth A. Wood; Reece J. Goiffon; Audrey J. Klingele; Eric L. Cabot; Wendy Schackwitz; Joel Martin; Julie Eggington; Timothy J. Durfee; Christina M. Middle; Jason E. Norton; Michael C. Popelars; Hao Li; Sarit A. Klugman; Lindsay L. Hamilton; Lukas B. Bane; Len A. Pennacchio; Thomas J. Albert; Nicole T. Perna; Michael M. Cox; John R. Battista

2009-01-01

275

Infant diarrhoea due to Escherichia coli 091 K? H7  

Microsoft Academic Search

A small outbreak of infective diarrhoea occurred among babies in hospital at Winchester, England. The causal agent was found to be a strain of Escherichia coli 091 K? H7 which was resistant to several antibiotics. Epidemic diarrhoea due to E. coli 091 has previously been reported from south Germany.

M. H. Hughes; J. L. Greaves; K. A. Bettelheim

1968-01-01

276

Existence of ?-methylnorleucine in recombinant hirudin produced by Escherichia coli  

Microsoft Academic Search

A gene encoding for hirudin, a potent thrombin inhibitor, was expressed in Escherichia coli, which is the most widely used host. When the recombinant hirudin analog, CX-397, was overproduced by E. coli (600 mg l?1) in the absence of nutrient amino acids in the culture medium, the presence of two derivatives in the final product was observed with extremely increased

Ryo Muramatsu; Toru Negishi; Tsutomu Mimoto; Akira Miura; Satoru Misawa; Hideya Hayashi

2002-01-01

277

New locus for exopolysaccharide overproduction in Escherichia coli K-12.  

PubMed Central

A new locus for exopolysaccharide overproduction in Escherichia coli K-12 was mapped by insertion mutagenesis. A 66% linkage to serA, which is located at 62 min on the E. coli K-12 linkage map, was shown by P1 transduction. The polysaccharide produced by the mutant was isolated and was shown to be similar to colanic acid.

Zinkewich-Peotti, K; Fraser, J M

1988-01-01

278

Pathotyping Escherichia coli by Using Miniaturized DNA Microarrays? †  

PubMed Central

The detection of virulence determinants harbored by pathogenic Escherichia coli is important for establishing the pathotype responsible for infection. A sensitive and specific miniaturized virulence microarray containing 60 oligonucleotide probes was developed. It detected six E. coli pathotypes and will be suitable in the future for high-throughput use.

Anjum, Muna F.; Mafura, Muriel; Slickers, Peter; Ballmer, Karin; Kuhnert, Peter; Woodward, Martin J.; Ehricht, Ralf

2007-01-01

279

Rapid glutamate decarboxylase assay for detection of Escherichia coli.  

PubMed Central

A rapid test procedure for the enzyme glutamate decarboxylase was developed for detection of Escherichia coli. The assay procedure was able to confirm the presence of E. coli in enteric broth cultures with 95% specificity for both pure cultures and environmental samples. The procedure was capable of detecting survivors among chlorine-exposed cells.

Rice, E W; Johnson, C H; Dunnigan, M E; Reasoner, D J

1993-01-01

280

Glucuronidase Activity Of Escherichia Coli Isolated From Chicken Carcasses  

PubMed Central

To identify Escherichia coli through the production of ?-D-glucuronidase (GUD), 622 suspect cultures were isolated from chicken carcasses and plated in Petrifilm™ EC. Of these cultures, only 44 (7.1%) failed to produce GUD. This result indicates the usefulness of GUD production for estimating E. coli populations in chicken.

Martins Perin, Luana; Keizo Yamazi, Anderson; Mendonca Moraes, Paula; Coutinho Cossi, Marcus Vinicius; Sergio de Arruda Pinto, Paulo; Augusto Nero*, Luis

2010-01-01

281

Genes Involved in Copper Homeostasis in Escherichia coli  

PubMed Central

Recently, genes for two copper-responsive regulatory systems were identified in the Escherichia coli chromosome. In this report, data are presented that support a hypothesis that the putative multicopper oxidase CueO and the transenvelope transporter CusCFBA are involved in copper tolerance in E. coli.

Grass, Gregor; Rensing, Christopher

2001-01-01

282

Biocontrol of Escherichia coli O157  

PubMed Central

The effect of a bacteriophage cocktail (EcoShield™) that is specific against Escherichia coli O157:H7 was evaluated against a nalidixic acid-resistant enterohemorrhagic E. coli O157:H7 RM4407 (EHEC) strain on leafy greens stored under either (1) ambient air or (2) modified atmosphere (MA; 5% O2/35% CO2/60% N2). Pieces (~2 × 2 cm2) of leafy greens (lettuce and spinach) inoculated with 4.5 log CFU/cm2 EHEC were sprayed with EcoShield™ (6.5 log PFU/cm2). Samples were stored at 4 or 10°C for up to 15 d. On spinach, the level of EHEC declined by 2.38 and 2.49 log CFU/cm2 at 4 and 10°C, respectively, 30 min after phage application (p ? 0.05). EcoShield™ was also effective in reducing EHEC on the surface of green leaf lettuce stored at 4°C by 2.49 and 3.28 log units in 30 min and 2 h, respectively (p ? 0.05). At 4°C under atmospheric air, the phage cocktail significantly (p ? 0.05) lowered the EHEC counts in one day by 1.19, 3.21 and 3.25 log CFU/cm2 on spinach, green leaf and romaine lettuce, respectively compared with control (no bacteriophage) treatments. When stored under MA at 4°C, phages reduced (p ? 0.05) EHEC populations by 2.18, 3.50 and 3.13 log CFU/cm2, on spinach, green leaf and romaine lettuce. At 10°C, EHEC reductions under atmospheric air storage were 1.99, 3.90 and 3.99 log CFU/cm2 (p ? 0.05), while population reductions under MA were 3.08, 3.89 and 4.34 logs on spinach, green leaf and romaine lettuce, respectively, compared with controls (p ? 0.05). The results of this study showed that bacteriophages were effective in reducing the levels of E. coli O157:H7 on fresh leafy produce, and that the reduction was further improved when produce was stored under the MA conditions.

Boyacioglu, Olcay; Sharma, Manan; Sulakvelidze, Alexander; Goktepe, Ipek

2013-01-01

283

Characterization of pili associated with Escherichia coli O18ac.  

PubMed Central

A strain of Escherichia coli O18ac isolated from the stool sample of a patient with diarrhea was found to agglutinate human erythrocytes. From the results presented it is suggested that this hemagglutination is mediated by pili. Isolated pilus preparations agglutinated human erythrocytes, whereas pilus-negative mutants did not. The serological and chemical analyses indicate that the pili associated with E. coli O18ac are distinct from other types found with E. coli. Images Fig. 1 Fig. 2 Fig. 3

Wevers, P; Picken, R; Schmidt, G; Jann, B; Jann, K; Golecki, J R; Kist, M

1980-01-01

284

Dehydrogenation of Conjugated Cholic Acid by Escherichia coli  

Microsoft Academic Search

7?-Dehydrogenation of taurocholic acid and glycocholic acid by Escherichia coli (E. coli) was examined in aerobic and anaerobic culture conditions. Bile acids in the culture medium of E. coli were extracted, separated into free, glycine-conjugate and taurine- conjugate fractions by piperidinohydroxypropyl dextran gel column chromatography, hydrolyzed in alkali and analyzed by gas-liquid chromatography. Both conjugated cholic acids were dehydrogenated to

Rie Katayama; Yoshio Ogura; Nobuo Yamaga; Koji Kimura; Kiyohisa Uchida

2004-01-01

285

Energetics of glycylglycine transport in Escherichia coli.  

PubMed

The transport system for glycylglycine in Escherichia coli behaves like a shock-sensitive transport system. The initial rate of transport is reduced 85% by subjecting whole cells to osmotic shock, and glycylglycine is not transported by membrane vesicles. The energetics of transport was studied with strain ML 308-225 and its mutant DL-54, which is deficient in Ca(2+)- and Mg(2+)-stimulated adenosine 5'-triphosphatase (EC 3.6.1.3) activity. It is concluded that active transport of glycylglycine, like other shock-sensitive transport systems, has an obligatory requirement for phosphate bond energy, but not for respiration or the energized state of the membrane. The major evidence for this conclusion is as follows. (i) Uptake of glycylglycine is severely inhibited by arsenate. (ii) Oxidizable energy sources such as d-lactate, succinate, and ascorbate, which is mediated by N-methylphenazinium methylsulfate, cannot serve as energy sources for the transport of glycylglycine in DL-54, which lacks oxidative phosphorylation. (iii) When energy is supplied only from adenosine-5'-triphosphate produced by glycolysis (anaerobic transport assays with glucose as the energy source in DL-54), substantial uptake of glycylglycine is observed. (iv) When the Ca(2+)-Mg(2+)-adenosine triphosphatase activity is absent but substrate-level phosphorylations and electron transport are operating (glucose as the energy source in DL-54), transport of glycylglycine shows significant resistance to the uncouplers, dinitrophenol and carbonyl cyanide-p-trifluoromethoxyphenylhydrazone. PMID:4278690

Cowell, J L

1974-10-01

286

Regulation of alcohol fermentation by Escherichia coli  

SciTech Connect

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.

Clark, D.P.

1986-03-01

287

Purification and crystallization of Escherichia coli oligoribonuclease.  

PubMed

Oligoribonuclease (Orn) is an essential 3'-to-5' hydrolytic exoribonuclease which degrades short oligoribonucleotides to 5' mononucleotides. Escherichia coli Orn has been crystallized under several different conditions using ammonium sulfate, sodium citrate and sodium acetate as precipitants. Both native and selenomethionine-labeled oligoribonuclease (SeMet-Orn) can be crystallized at room temperature in 1.4-1.55 M sodium citrate. The SeMet-Orn crystals diffract to 2.2 A resolution and belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 70.43, b = 72.87, c = 147.76 A, and two dimers in the asymmetric unit. When grown in the presence of manganese, a second crystal form (Mn-SeMet-Orn) was obtained containing a single dimer per asymmetric unit (P2(1)2(1)2(1); a = 63.74, b = 74.31, c = 74.19 A). Finally, a hexagonal crystal form was obtained using sodium acetate as a precipitant (a = 91.5, b = 91.5, c = 111.1 A). This crystal (Zn-ApUp-Orn) belongs to the P6(5) space group and has three oligoribonuclease molecules per asymmetric unit. PMID:15039570

Fiedler, Tristan J; Vincent, Helen A; Zuo, Yuhong; Gavrialov, Orit; Malhotra, Arun

2004-04-01

288

Mutagenesis in Escherichia coli lacking catalase.  

PubMed

Escherichia coli K-12 strains completely lacking catalase activity due to mutations in katG, katE, and katF genes were constructed in order to assess the role of hydrogen peroxide in mutagenesis. Mutagenesis was monitored by selecting forward mutations to L-arabinose resistance. Lethality was measured at experimental conditions equivalent to those of the mutant yield by using a mixed culture of pairs of isogenic strains distinguished by their differential nutritional requirements. Deficiency in katG, katE, and katF genes leads to an enhanced spontaneous mutation rate as well as an enhanced sensitivity to both the lethal and mutagenic effects of hydrogen peroxide or an H2O2-generating mixture of compounds, such as coffee. To compare further the responses of the catalase-deficient bacteria to those of catalase-proficient counterparts, other genotoxins were analyzed. Both catalase-deficient and catalase-proficient strains were equally mutated by MMS, 4-NQO, and ultraviolet light. It is concluded that the bacterial strains and the mutagenicity tests described in the paper represent a useful tool to study the role of H2O2 in mutagenesis. PMID:2192882

Abril, N; Pueyo, C

1990-01-01

289

Oligosaccharide Binding in Escherichia coli Glycogen Synthase  

SciTech Connect

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.

Sheng, Fang; Yep, Alejandra; Feng, Lei; Preiss, Jack; Geiger, James H.; (MSU)

2010-11-17

290

Control ofPyridoxine Biosynthesis inEscherichia coli  

Microsoft Academic Search

DEMPSEY,WALTERB.(Uniiversity ofFlorida, Gainesville). Controlofpyridoxine biosynthesis inEscherichia coli. J.Bacteriol. 90:431-437. 1965.-The total pyridoxine in a culture ofexponentially growing Escherichia coli was 3.6X 10-10 molespermg ofdry cells. One-fourth ofthistotal was present inthemedium, andwas atleast 90%pyridoxal 5'-phosphate. Bothpyridoxol andpyridoxal, whenpresent initially at6X 10-7M, substituted entirely fordenovo synthesis ofpyridoxine. Theotherfourformsofthe pyridoxine group were ineffective atthisconcentration. Pyridoxine biosynthesis in exponentially growing cultures ofE.coli was immediately

WALTER B. DEMPSEY

1965-01-01

291

76 FR 72331 - Shiga Toxin-Producing Escherichia coli in Certain Raw Beef Products  

Federal Register 2010, 2011, 2012, 2013

...STEC) Escherichia coli (E. coli). The document also...steaks and roasts, for E. coli serogroups O26, O45...entering commerce. Like E. coli O157:H7, these serogroups...for Disease Control and Prevention also identifies...

2011-11-23

292

Enzymatically Active and Inactive Phosphodiesterases and Diguanylate Cyclases Are Involved in Regulation of Motility or Sessility in Escherichia coli CFT073  

PubMed Central

ABSTRACT Intracellular concentration of cyclic diguanylate monophosphate (c-di-GMP), a second messenger molecule, is regulated in bacteria by diguanylate cyclases (DGCs) (synthesizing c-di-GMP) and phosphodiesterases (PDEs) (degrading c-di-GMP). c-di-GMP concentration ([c-di-GMP]) affects motility and sessility in a reciprocal fashion; high [c-di-GMP] typically inhibits motility and promotes sessility. A c-di-GMP sensor domain, PilZ, also regulates motility and sessility. Uropathogenic Escherichia coli regulates these processes during infection; motility is necessary for ascending the urinary tract, while sessility is essential for colonization of anatomical sites. Here, we constructed and screened 32 mutants containing deletions of genes encoding each PDE (n = 11), DGC (n = 13), PilZ (n = 2), and both PDE and DGC (n = 6) domains for defects in motility, biofilm formation, and adherence for the prototypical pyelonephritis isolate E. coli CFT073. Three of 32 mutations affected motility, all of which were in genes encoding enzymatically inactive PDEs. Four PDEs, eight DGCs, four PDE/DGCs, and one PilZ regulated biofilm formation in a medium-specific manner. Adherence to bladder epithelial cells was regulated by [c-di-GMP]. Four PDEs, one DGC, and three PDE/DGCs repress adherence and four DGCs and one PDE/DGC stimulate adherence. Thus, specific effectors of [c-di-GMP] and catalytically inactive DGCs and PDEs regulate adherence and motility in uropathogenic E. coli.

Spurbeck, Rachel R.; Tarrien, Rebecca J.; Mobley, Harry L. T.

2012-01-01

293

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

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.

Salvador, Ellaine; Wagenlehner, Florian; Kohler, Christian-Daniel; Mellmann, Alexander; Hacker, Jorg; Svanborg, Catharina

2012-01-01

294

Insights into a Multidrug Resistant Escherichia coli Pathogen of the Globally Disseminated ST131 Lineage: Genome Analysis and Virulence Mechanisms  

PubMed Central

Escherichia coli strains causing urinary tract infection (UTI) are increasingly recognized as belonging to specific clones. E. coli clone O25b:H4-ST131 has recently emerged globally as a leading multi-drug resistant pathogen causing urinary tract and bloodstream infections in hospitals and the community. While most molecular studies to date examine the mechanisms conferring multi-drug resistance in E. coli ST131, relatively little is known about their virulence potential. Here we examined E. coli ST131 clinical isolates from two geographically diverse collections, one representing the major pathogenic lineages causing UTI across the United Kingdom and a second representing UTI isolates from patients presenting at two large hospitals in Australia. We determined a draft genome sequence for one representative isolate, E. coli EC958, which produced CTX-M-15 extended-spectrum ?-lactamase, CMY-23 type AmpC cephalosporinase and was resistant to ciprofloxacin. Comparative genome analysis indicated that EC958 encodes virulence genes commonly associated with uropathogenic E. coli (UPEC). The genome sequence of EC958 revealed a transposon insertion in the fimB gene encoding the activator of type 1 fimbriae, an important UPEC bladder colonization factor. We identified the same fimB transposon insertion in 59% of the ST131 UK isolates, as well as 71% of ST131 isolates from Australia, suggesting this mutation is common among E. coli ST131 strains. Insertional inactivation of fimB resulted in a phenotype resembling a slower off-to-on switching for type 1 fimbriae. Type 1 fimbriae expression could still be induced in fimB-null isolates; this correlated strongly with adherence to and invasion of human bladder cells and bladder colonisation in a mouse UTI model. We conclude that E. coli ST131 is a geographically widespread, antibiotic resistant clone that has the capacity to produce numerous virulence factors associated with UTI.

Sarkar, Sohinee; Phan, Minh-Duy; Petty, Nicola K.; Bachmann, Nathan; Szubert, Marek; Sidjabat, Hanna E.; Paterson, David L.; Upton, Mathew; Schembri, Mark A.

2011-01-01

295

Cranberry Products Inhibit Adherence of P-Fimbriated Escherichia Coli to Primary Cultured Bladder and Vaginal Epithelial Cells  

PubMed Central

Purpose Cranberry proanthocyanidins have been identified as possible inhibitors of Escherichia coli adherence to uroepithelial cells. However, little is known about the dose range of this effect. Furthermore, it has not been studied directly in the urogenital system. To address these issues we tested the effect of a cranberry powder and proanthocyanidin extract on adherence of a P-fimbriated uropathogenic E. coli isolate to 2 new urogenital model systems, namely primary cultured bladder epithelial cells and vaginal epithelial cells. Materials and Methods E. coli IA2 was pre-incubated with a commercially available cranberry powder (9 mg proanthocyanidin per gm) or with increasing concentrations of proanthocyanidin extract. Adherence of E. coli IA2 to primary cultured bladder epithelial cells or vaginal epithelial cells was measured before and after exposure to these products. Results Cranberry powder decreased mean adherence of E. coli IA2 to vaginal epithelial cells from 18.6 to 1.8 bacteria per cell (p <0.001). Mean adherence of E. coli to primary cultured bladder epithelial cells was decreased by exposure to 50 ?g/ml proanthocyanidin extract from 6.9 to 1.6 bacteria per cell (p <0.001). Inhibition of adherence of E. coli by proanthocyanidin extract occurred in linear, dose dependent fashion over a proanthocyanidin concentration range of 75 to 5 ?g/ml. Conclusions Cranberry products can inhibit E. coli adherence to biologically relevant model systems of primary cultured bladder and vaginal epithelial cells. This effect occurs in a dose dependent relationship. These findings provide further mechanistic evidence and biological plausibility for the role of cranberry products for preventing urinary tract infection.

Gupta, K.; Chou, M. Y.; Howell, A.; Wobbe, C.; Grady, R.; Stapleton, A. E.

2011-01-01

296

The function of ubiquinone in Escherichia coli  

PubMed Central

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 proposed in which ubisemiquinone, complexed to an electron carrier, functions in at least two positions in the electron-transport sequence.

Cox, G. B.; Newton, N. A.; Gibson, F.; Snoswell, A. M.; Hamilton, J. A.

1970-01-01

297

Reproducible gene targeting in recalcitrant Escherichia coli isolates  

PubMed Central

Background A number of allele replacement methods can be used to mutate bacterial genes. For instance, the Red recombinase system of phage Lambda has been used very efficiently to inactivate chromosomal genes in E. coli K-12, through recombination between regions of homology. However, this method does not work reproducibly in some clinical E. coli isolates. Findings The procedure was modified by using longer homologous regions (85 bp and 500-600 bp), to inactivate genes in the uropathogenic E. coli strain UTI89. An lrhA regulator mutant, and deletions of the lac operon as well as the complete type 1 fimbrial gene cluster, were obtained reproducibly. The modified method is also functional in other recalcitrant E. coli, like the avian pathogenic E. coli strain APEC1. The lrhA regulator and lac operon deletion mutants of APEC1 were successfully constructed in the same way as the UTI89 mutants. In other avian pathogenic E. coli strains (APEC3E, APEC11A and APEC16A) it was very difficult or impossible to construct these mutants, with the original Red recombinase-based method, with a Red recombinase-based method using longer (85 bp) homologous regions or with our modified protocol, using 500 - 600 bp homologous regions. Conclusions The method using 500-600 bp homologous regions can be used reliably in some clinical isolates, to delete single genes or entire operons by homologous recombination. However, it does not invariably show a greater efficiency in obtaining mutants, when compared to the original Red-mediated gene targeting method or to the gene targeting method with 85 bp homologous regions. Therefore the length of the homology regions is not the only limiting factor for the construction of mutants in these recalcitrant strains.

2011-01-01

298

Role of Homologous Recombination in Adaptive Diversification of Extraintestinal Escherichia coli  

PubMed Central

The contribution of homologous exchange (recombination) of core genes in the adaptive evolution of bacterial pathogens is not well understood. To investigate this, we analyzed fully assembled genomes of two Escherichia coli strains from sequence type 131 (ST131), a clonal group that is both the leading cause of extraintestinal E. coli infections and the main source of fluoroquinolone-resistant E. coli. Although the sequences of each of the seven multilocus sequence typing genes were identical in the two ST131 isolates, the strains diverged from one another by homologous recombination that affected at least 9% of core genes. This was on a par with the contribution to genomic diversity of horizontal gene transfer and point gene mutation. The genomic positions of recombinant and mobile genetic regions were partially linked, suggesting their concurrent occurrence. One of the genes affected by homologous recombination was fimH, which encodes mannose-specific type 1 fimbrial adhesin, resulting in functionally distinct copies of the gene in ST131 strains. One strain, a uropathogenic isolate, had a pathoadaptive variant of fimH that was acquired by homologous replacement into the commensal strain background. Close examination of FimH structure and function in additional ST131 isolates revealed that recombination led to acquisition of several functionally distinct variants that, upon homologous exchange, were targeted by a variety of pathoadaptive mutations under strong positive selection. Different recombinant fimH strains also showed a strong clonal association with ST131 isolates that had distinct fluoroquinolone resistance profiles. Thus, homologous recombination of core genes plays a significant role in adaptive diversification of bacterial pathogens, especially at the level of clonally related groups of isolates.

Paul, Sandip; Linardopoulou, Elena V.; Billig, Mariya; Tchesnokova, Veronika; Price, Lance B.; Johnson, James R.; Chattopadhyay, Sujay

2013-01-01

299

Rates of mutation and host transmission for an Escherichia coli clone over 3 years.  

PubMed

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. PMID:22046404

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

300

Sensitivity to Escherichia coli Nissle 1917 in mice is dependent on environment and genetic background  

PubMed Central

Escherichia coli Nissle 1917 (EcN) is a well-characterized probiotic bacterium. Although genomic comparisons of EcN with the uropathogenic E. coli strain CFT073 revealed high degrees of similarity, EcN is generally considered a non-pathogenic organism. However, as recent evidence suggests that EcN is capable of inducing inflammatory responses in host intestinal epithelial cells, we aimed to investigate potential pathogenic properties of EcN in an in vivo model using various germ-free (GF) mouse strains. With the exception of C3H/HeJZtm mice, which carry a defective toll-like receptor (TLR)4-allele, no lesions were obvious in mice of different strains orally inoculated with EcN for 1 week, although organ cultures (blood, lung, mesenteric lymph node, pancreas, spleen, liver and kidney) tested positive to various degrees. C3H/HeJZtm mice inoculated with EcN became clinically ill and the majority died or had to be euthanized. Organs of all gnotobiotic C3H/HeJZtm mice were positive for EcN by culture; major histological findings were moderate to severe pyogranulomatous serositis, typhlitis and pancreatitis. Histological findings were corroborated by highly elevated tumour necrosis factor (TNF) serum levels. Lesions were not detected in specified pathogen free maintained C3H/HeJZtm mice, GF C3H/HeJ mice lacking the interleukin-10 gene, or GF C3H/HeJZtm mice that were inoculated with E. coli K12 strain MG1655 as a control. In addition, mild histological lesions were detected in Ztm:NMRI mice 3 months after oral inoculation with EcN. This study shows that EcN is capable of displaying a virulent phenotype in GF C3H/HeJZtm mice. Whether this phenotype is linked to the bacterium’s probiotic nature should be the focus of further studies.

Bleich, Andre; Sundberg, John P; Smoczek, Anna; von Wasielewski, Reinhard; de Buhr, Maike F; Janus, Lydia M; Julga, Gwen; Ukena, Sya N; Hedrich, Hans-J; Gunzer, Florian

2008-01-01

301

Inhibition of Escherichia coli CFT073 fliC expression and motility by cranberry materials.  

PubMed

In humans, uropathogenic Escherichia coli (UPEC) is the most common etiological agent of uncomplicated urinary tract infections (UTIs). Cranberry extracts have been linked to the prevention of UTIs for over a century; however, a mechanistic understanding of the way in which cranberry derivatives prevent bacterial infection is still lacking. In this study, we used a fliC-lux reporter as well as quantitative reverse transcription-PCR to demonstrate that when UPEC strain CFT073 was grown or exposed to dehydrated, crushed cranberries or to purified cranberry-derived proanthocyanidins (cPACs), expression of the flagellin gene (fliC) was inhibited. In agreement with these results, transmission electron microscopy imaging of bacteria grown in the presence of cranberry materials revealed fewer flagella than those in bacteria grown under control conditions. Furthermore, we showed that swimming and swarming motilities were hindered when bacteria were grown in the presence of the cranberry compounds. Because flagellum-mediated motility has been suggested to enable UPEC to disseminate to the upper urinary tract, we propose that inhibition of flagellum-mediated motility might be a key mechanism by which cPACs prevent UTIs. This is the first report to show that cranberry compounds inhibit UPEC motility via downregulation of the fliC gene. Further studies are required to establish whether these inhibitors play a role in vivo. PMID:21821749

Hidalgo, Gabriela; Chan, Michelle; Tufenkji, Nathalie

2011-10-01

302

A Central Metabolic Circuit Controlled by QseC in Pathogenic Escherichia coli  

PubMed Central

Summary The QseC sensor kinase regulates virulence in multiple gram-negative pathogens, by controlling the activity of the QseB response regulator. We have previously shown that qseC deletion interferes with dephosphorylation of QseB thus unleashing what appears to be an uncontrolled positive feedback loop stimulating increased QseB levels. Deletion of QseC downregulates virulence gene expression and attenuates enterohemorrhagic and uropathogenic Escherichia coli (EHEC and UPEC), Salmonella typhimurium, and Francisella tularensis. Given that these pathogens employ different infection strategies and virulence factors, we used genome-wide approaches to better understand the role of the QseBC interplay in pathogenesis. We found that deletion of qseC results in misregulation of nucleotide, amino acid, and carbon metabolism. Comparable metabolic changes are seen in EHEC ?qseC, suggesting that deletion of qseC confers similar pleiotropic effects in these two different pathogens. Disruption of representative metabolic enzymes phenocopied UPEC ?qseC in vivo and resulted in virulence factor downregulation. We thus propose that in the absence of QseC, the constitutively active QseB leads to pleiotropic effects, impairing bacterial metabolism, and thereby attenuating virulence. These findings provide a basis for the development of anti-microbials targeting the phosphatase activity of QseC, as a means to attenuate a wide range of QseC-bearing pathogens.

Hadjifrangiskou, Maria; Kostakioti, Maria; Chen, Swaine L.; Henderson, Jeffrey P.; Greene, Sarah E.; Hultgren, Scott J.

2012-01-01

303

Very slow growth of Escherichia coli.  

PubMed Central

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

Chesbro, W; Evans, T; Eifert, R

1979-01-01

304

Rapid Sterilization of Escherichia coli by Solution Plasma Process  

NASA Astrophysics Data System (ADS)

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.

Andreeva, Nina; Ishizaki, Takahiro; Baroch, Pavel; Saito, Nagahiro

2012-12-01

305

A rapid procedure to purify Escherichia coli DNA topoisomerase I.  

PubMed

On the basis of the asymmetrical charge distribution of Escherichia coli DNA topoisomerase I, we developed a new procedure to purify E. coli DNA topoisomerase I in the milligram range. The new procedure includes using both cation- and anion-exchange columns, i.e., SP-Sepharose FF and Q-Sepharose FF columns. The E. coli DNA topoisomerase I purified here is free of DNase contamination. The kinetic constants of the DNA relaxation reaction of E. coli DNA topoisomerase I were also determined. PMID:21310243

Xu, Xiaozhou; Leng, Fenfei

2011-06-01

306

Intestinal Colonization by Enterotoxigenic Escherichia coli.  

National Technical Information Service (NTIS)

Intestinal colonization and adhesion by enterotoxigenic E. coli is mediated by specific types of pili. These pili are antigenic and can be used in diagnosing enterotoxigenic E. coli infections. They are also good protective antigens. When pregnant dams ar...

H. W . Moon

1980-01-01

307

Intestinal Colonization by Enterotoxigenic 'Escherichia coli.'.  

National Technical Information Service (NTIS)

Growth of enterotoxigenic E. coli in porcine small intestine selects for piliated forms which adhere to the intestinal epithelium. Surface antigen K99 on enterotoxigenic E. coli is a pilus. Antigen K99 occurs on porcine enterotoxigenic E. coli strains and...

H. W. Moon

1976-01-01

308

Clonal composition of Escherichia coli causing community-acquired urinary tract infections in the State of Rio de Janeiro, Brazil.  

PubMed

Recent studies from North America and Europe have demonstrated community-wide clonal spread of uropathogenic Escherichia coli (UPEC). To investigate if a similar pattern of spread occurs in Brazil, we characterized UPEC from women with community-acquired urinary tract infection (UTI) in Rio de Janeiro. E. coli isolates from women with UTI in one public outpatient clinic were evaluated for antibiotic susceptibility, E. coli phylogenetic grouping, enterobacterial repetitive intergenic consensus (ERIC) 2 PCR and pulsed-field gel electrophoresis fingerprinting, and multilocus sequence typing. From March 2005 to November 2006, 344 patients were studied. Of these, 186 (54%) had confirmed UTI, 118 (63.4%) of which were caused by E. coli. More than 50% of these isolates were resistant to ampicillin and trimethoprim/sulfamethoxazole. Of these, 96 (81%) belonged to 19 ERIC2 clonal groups. The largest group included 15 isolates, all belonging to multilocus sequence typing group ST69 and phylogenetic group D; they had pulsed-field gel electrophoresis patterns sharing at least 89% similarity compared with the CgA reference strain ATCC BAA-457. CgA strains have been found to be widespread in the United States in the early 2000s. Clonal group E. coli strains accounted for a large proportion (52%) of all UTIs and 82% of the trimethoprim/sulfamethoxazole-resistant E. coli UTIs. Thus, as in North America and Europe, UPECs that cause UTI in Rio de Janeiro also show clonal distribution, and a substantial proportion of drug-resistant UTI is caused by a small set of genetically related E. coli strains. PMID:19857137

Dias, Rubens C S; Marangoni, Denise V; Smith, Sherry P; Alves, Elizabeth M; Pellegrino, Flavia L P C; Riley, Lee W; Moreira, Beatriz M

2009-12-01

309

Diarrheagenic Escherichia coli in Children from Costa Rica  

PubMed Central

More than 5,000 diarrheal cases per year receive medical care at the National Children's Hospital of Costa Rica, and nearly 5% of them require hospitalization. A total of 173 Escherichia coli strains isolated from children with diarrhea were characterized at the molecular, serologic, and phenotypic level. Multiplex and duplex polymerase chain reactions were used to detect the six categories of diarrheagenic E. coli. Thirty percent (n = 52) of the strains were positive, indicating a high prevalence among the pediatric population. Enteropathogenic E. coli and enteroinvasive E. coli pathotypes were the most prevalent (21% and 19%, respectively). Pathogenic strains were distributed among the four E. coli phylogenetic groups A, B1, B2, and D, with groups A and B1 the most commonly found. This study used molecular typing to evaluate the prevalence of diarrheagenic E. coli reported in Costa Rica and demonstrated the importance of these pathotypes in the pediatric population.

Perez, Cristian; Gomez-Duarte, Oscar G.; Arias, Maria L.

2010-01-01

310

Infection by verocytotoxin-producing Escherichia coli.  

PubMed Central

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 with human disease is O157:H7, but over 50 different VT-positive O:H serotypes have now been identified. The best strategies for diagnosing human VTEC infection include testing for the presence of free VT in fecal filtrates and examining fecal cultures for VTEC by means of deoxyribonucleic acid probes that specify genes encoding VT1 and VT2. Both methods are currently confined to specialized laboratories and await commercial development for wider use. In the meantime, most laboratories should continue to screen for the most common human VTEC serotype, O157:H7, using a sorbitol-containing MacConkey medium. Images

Karmali, M A

1989-01-01

311

Pathogenomics of the Virulence Plasmids of Escherichia coli  

PubMed Central

Summary: Bacterial plasmids are self-replicating, extrachromosomal elements that are key agents of change in microbial populations. They promote the dissemination of a variety of traits, including virulence, enhanced fitness, resistance to antimicrobial agents, and metabolism of rare substances. Escherichia coli, perhaps the most studied of microorganisms, has been found to possess a variety of plasmid types. Included among these are plasmids associated with virulence. Several types of E. coli virulence plasmids exist, including those essential for the virulence of enterotoxigenic E. coli, enteroinvasive E. coli, enteropathogenic E. coli, enterohemorrhagic E. coli, enteroaggregative E. coli, and extraintestinal pathogenic E. coli. Despite their diversity, these plasmids belong to a few plasmid backbones that present themselves in a conserved and syntenic manner. Thanks to some recent research, including sequence analysis of several representative plasmid genomes and molecular pathogenesis studies, the evolution of these virulence plasmids and the implications of their acquisition by E. coli are now better understood and appreciated. Here, work involving each of the E. coli virulence plasmid types is summarized, with the available plasmid genomic sequences for several E. coli pathotypes being compared in an effort to understand the evolution of these plasmid types and define their core and accessory components.

Johnson, Timothy J.; Nolan, Lisa K.

2009-01-01

312

The Complete Genome Sequence of Escherichia coli K-12  

Microsoft Academic Search

The 4,639,221- base pair sequence of Escherichia coli K-12 is presented. Of 4288 protein-coding genes annotated, 38 percent have no attributed function. Comparison with five other sequenced microbes reveals ubiquitous as well as narrowly distributed gene families; many families of similar genes within E. coli are also evident. The largest family of paralogous proteins contains 80 ABC transporters. The genome

Frederick R. Blattner; Guy Plunkett III; Craig A. Bloch; Nicole T. Perna; Valerie Burland; Monica Riley; Julio Collado-Vides; Jeremy D. Glasner; Christopher K. Rode; George F. Mayhew; Jason Gregor; Nelson Wayne Davis; Heather A. Kirkpatrick; Michael A. Goeden; Debra J. Rose; Bob Mau; Ying Shao

2007-01-01

313

Azo dye decolorization with a mutant Escherichia coli strain  

Microsoft Academic Search

A recombinant Escherichia coli strain (E. coli NO3) containing genomic DNA fragments from azo-reducing wild-type Pseudomonas luteola strain decolorized a reactive azo dye (C.I. Reactive Red 22) at approx. 17 mg dye h-1 g cell. The ability to decolorize the azo dye probably did not originate from the plasmid DNA. Acclimation in azo-dye-containing media gave a nearly 10% increase in the decolorization rate of

Jo-Shu Chang; Tai-Shin Kuo; Yun-Peng Chao; Jin-Yen Ho; Ping-Jei Lin

2000-01-01

314

Major virulence factors of enterotoxigenic Escherichia coli in pigs  

Microsoft Academic Search

Enterotoxigenic Escherichia coli (ETEC) infection is the most common type of colibacillosis of young animals, and it is also a significant cause of food-\\u000a and waterborne E. coli-mediated human diarrhea worldwide. ETEC is a pathotype characterized by the production of adhesins that mediate bacterial\\u000a adherence to the intestinal epithelium and enterotoxins that interact with the intestine to cause diarrhea. In

Qiangde Duan; Fenghua Yao; Guoqiang Zhu

315

Indole Can Act as an Extracellular Signal in Escherichia coli  

Microsoft Academic Search

Previous work has shown that lacZ fusions to the cysK, astD, tnaB, and gabT genes in Escherichia coli are activated by self-produced extracellular signals. Using a combination of ethyl acetate extraction, reversed- phase C18 chromatography, and thin-layer chromatography, we have purified an extracellular activating signal from E. coli supernatants. Mass spectrometry revealed a molecule with an m\\/z peak of 117,

DANDAN WANG; XUEDONG DING

2001-01-01

316

Recombinational Construction in Escherichia coli of Infectious Adenoviral Genomes  

Microsoft Academic Search

A two-step gene replacement procedure was developed that generates infectious adenoviral genomes through homologous recombination in Escherichia coli. As a prerequisite, a human adenovirus serotype 5 (Ad5)-derived genome was first introduced as a PacI restriction fragment into an incP-derived replicon which, in contrast to ColE1-derivatives (e.g., pBR322 or pUC plasmids), is functional in a polA mutant of E. coli. Any

Joel Crouzet; Laurent Naudin; Cecile Orsini; Emmanuelle Vigne; Lucy Ferrero; Aude Le Roux; Patrick Benoit; Martine Latta; Christophe Torrent; Didier Branellec; Patrice Denefle; Jean-Francois Mayaux; Michel Perricaudet; Patrice Yeh

1997-01-01

317

DEFINITION OF ADDITIONAL FLAGELLAR GENES IN ESCHERICHIA COLI K12  

Microsoft Academic Search

Twentynine flagellar genes in Escherichia coli K12 have previously been assigned to three regions of the genome. Flagellar region I is located between pyrC and ptsG, region I1 between aroD and uvrC, and region I11 between uvrC and his. In this study, flagellar mutants in EscherLchia coli K12 were obtained by selection for resistance to the flagellotropic phage, x. They

YOSHIBUMI KOMEDA; KAZUHIRO KUTSUKAKE; TETSUO IINO

318

Characterization of a Second Lysine Decarboxylase Isolated from Escherichia coli  

Microsoft Academic Search

We report here on the existence of a new gene for lysine decarboxylase in Escherichia coli K-12. The hybridization experiments with a cadA probe at low stringency showed that the homologous region of cadA was located in l Kohara phage clone 6F5 at 4.7 min on the E. coli chromosome. We cloned the 5.0-kb HindIII fragment of this phage clone

YOSHIMI KIKUCHI; HIROYUKI KOJIMA; TAKASHI TANAKA; YUMIKO TAKATSUKA; YOSHIYUKI KAMIO

1997-01-01

319

Assembly of a Functional Immunoglobulin Fv Fragment in Escherichia coli  

Microsoft Academic Search

An expression system was developed that allows the production of a completely functional antigen-binding fragment of an antibody in Escherichia coli. The variable domains of the phosphorylcholine-binding antibody McPC603 were secreted together into the periplasmic space, where protein folding as well as heterodimer association occurred correctly. Thus, the assembly pathway for the Fv fragment in E. coli is similar to

Arne Skerra; Andreas Pluckthun

1988-01-01

320

Enhanced expression of CYP1B1 in Escherichia coli  

Microsoft Academic Search

Conditions for the optimal expression of the human CYP1B1 hemoprotein in Escherichia coli have been investigated. CYP1B1 cDNA was prepared from a retinal cDNA template and used to generate cDNA fragments with modified 5?-sequences reported to allow enhanced expression in E. coli DH5?. Plasmids were constructed, using the pCWori+ expression vector and were used to examine necessity for thiamine, ?-aminolevulinic

Ingela Jansson; Ivaylo Stoilov; Mansoor Sarfarazi; John B Schenkman

2000-01-01

321

In vitro antibacterial effect of yogurt on Escherichia coli  

Microsoft Academic Search

We investigated the bactericidal and bacteriostatic effects of yogurt on three strains ofEscherichia coli: human toxigenic (078:H11), rabbit pathogenic (RDEC-1) and rabbit nonpathogenic [015:K14(L):H4]. Approximately 106 organisms were incubated in yogurt, milk, broth, and modifications of these materials. Aliquots were removed at various intervals and plated on MacConkey's agar for enumeration ofE. coli. Yogurt was bactericidal (at least 5 log10

Catherine M. Kotz; Lance R. Peterson; Julia A. Moody; Dennis A. Savaiano; Michael D. Levitt

1990-01-01

322

A functional update of the Escherichia coli K-12 genome  

Microsoft Academic Search

BACKGROUND: Since the genome of Escherichia coli K-12 was initially annotated in 1997, additional functional information based on biological characterization and functions of sequence-similar proteins has become available. On the basis of this new information, an updated version of the annotated chromosome has been generated. RESULTS: The E. coli K-12 chromosome is currently represented by 4,401 genes encoding 116 RNAs

Margrethe H Serres; Shuba Gopal; Laila A Nahum; Ping Liang; Terry Gaasterland; Monica Riley

2001-01-01

323

Actividad antimicrobiana de mieles del sudeste de la provincia de Buenos Aires frente a Escherichia coli  

Microsoft Academic Search

Antimicrobial activity of honey against Escherichia coli. This study assessed the susceptibility of Escherichia coli to the antimicrobial activity of honeys by different techniques. Honeys used were from the southeast region of Buenos Aires province. In order to evaluate antimicrobial activity against Escherichia coli ATCC 25922, solutions containing 0, 1, 5, 10, 25 and 50% (w\\/v) of honey were prepared.

M. F. FANGIO; M. O. IURLINA; R. FRITZ

2007-01-01

324

Use of EC-MUG Media to Confirm Escherichia coli Contamination in Water Samples Protocol  

NSDL National Science Digital Library

Escherichia coli broth and Escherichia coli agar media with 4-methylumbelliferyl-Ă-D-glucuronide are used to confirm the presence of Escherichia coli in water samples. In this protocol, the history, procedure, and interpretation of results of this useful technique are discussed in detail.

American Society For Microbiology;

2010-08-23

325

Role of the rapA Gene in Controlling Antibiotic Resistance of Escherichia coli Biofilms? †  

PubMed Central

By using a high-throughput screening method, a mutant of a uropathogenic Escherichia coli strain affected in the rapA gene was isolated. The mutant formed normal-architecture biofilms but showed decreased penicillin G resistance, although the mutation did not affect planktonic cell resistance. Transcriptome analysis showed that 22 genes were down-regulated in the mutant biofilm. One of these genes was yhcQ, which encodes a putative multidrug resistance pump. Mutants with mutations in this gene also formed biofilms with decreased resistance, although the effect was less pronounced than that of the rapA mutation. Thus, an additional mechanism(s) controlled by a rapA-regulated gene(s) was involved in wild-type biofilm resistance. The search for this mechanism was guided by the fact that another down-regulated gene in rapA biofilms, yeeZ, is suspected to be involved in extra cell wall-related functions. A comparison of the biofilm matrix of the wild-type and rapA strains revealed decreased polysaccharide quantities and coverage in the mutant biofilms. Furthermore, the (fluorescent) functional penicillin G homologue Bocillin FL penetrated the mutant biofilms more readily. The results strongly suggest a dual mechanism for the wild-type biofilm penicillin G resistance, retarded penetration, and effective efflux. The results of studies with an E. coli K-12 strain pointed to the same conclusion. Since efflux and penetration can be general resistance mechanisms, tests were conducted with other antibiotics. The rapA biofilm was also more sensitive to norfloxacin, chloramphenicol, and gentamicin.

Lynch, S. V.; Dixon, L.; Benoit, M. R.; Brodie, E. L.; Keyhan, M.; Hu, P.; Ackerley, D. F.; Andersen, G. L.; Matin, A.

2007-01-01

326

Genotyping of ESBL Producing Uropathogenic Escherichia coli in West of Iran  

PubMed Central

Background and Objective. Urinary tract infection (UTI) is one of the most common bacterial infections in the world. Molecular fingerprinting of UTI isolates such as pulsed-Field Gel Electrophoresis using for Clonal distribution and determine of predominant type. The aim of the study was to determine genotyping of ESBL producing UPECs. Material and Methods. 200 UPEC isolates from outpatients with UTI were obtained. Antimicrobial susceptibility and interpretation were performed by disk diffusion. Virulence factors for UPECs were screened by using PCR. UPECs were analyzed by Pulsed-Field Gel Electrophoresis and images analyzed by Phoretix1DPro software. Results. A total of 200 isolates of UPECs, 24.5% (n = 49) of isolates, were positive for ESBL production. Resistance ranged from 0% for amikacin and imipenem to over 93.9% for carbenicillin and ampicillin. Frequencies of haemagglutination, haemolysin, and hydrophobicity were 51%, 18.3%, and 14.28%, respectively. A total of 10 different genotypes were obtained, which include nine common clones and one single clone. Conclusion. We confirmed the prevalence of virulence phenotyping especially Haemagglutination among UPEC strains and that it can also contribute to virulence in these strains. Large diversity in genotypes was observed in the isolates that could be indicative of different sources of infection in community acquired.

Darfarin, Gita

2014-01-01

327

Genotyping of ESBL Producing Uropathogenic Escherichia coli in West of Iran.  

PubMed

Background and Objective. Urinary tract infection (UTI) is one of the most common bacterial infections in the world. Molecular fingerprinting of UTI isolates such as pulsed-Field Gel Electrophoresis using for Clonal distribution and determine of predominant type. The aim of the study was to determine genotyping of ESBL producing UPECs. Material and Methods. 200 UPEC isolates from outpatients with UTI were obtained. Antimicrobial susceptibility and interpretation were performed by disk diffusion. Virulence factors for UPECs were screened by using PCR. UPECs were analyzed by Pulsed-Field Gel Electrophoresis and images analyzed by Phoretix1DPro software. Results. A total of 200 isolates of UPECs, 24.5% (n = 49) of isolates, were positive for ESBL production. Resistance ranged from 0% for amikacin and imipenem to over 93.9% for carbenicillin and ampicillin. Frequencies of haemagglutination, haemolysin, and hydrophobicity were 51%, 18.3%, and 14.28%, respectively. A total of 10 different genotypes were obtained, which include nine common clones and one single clone. Conclusion. We confirmed the prevalence of virulence phenotyping especially Haemagglutination among UPEC strains and that it can also contribute to virulence in these strains. Large diversity in genotypes was observed in the isolates that could be indicative of different sources of infection in community acquired. PMID:24839441

Mohajeri, Parviz; Darfarin, Gita; Farahani, Abbas

2014-01-01

328

Glycolipid Receptors of F1C Fimbrial Adhesin of Uropathogenic Escherichia coli  

Microsoft Academic Search

The ability of F1C fimbriated bacteria to bind to the human urinary tract could be demonstrated by performing binding studies using several different cell lines as shown in table 1, and by performing direct binding assay using human bladder epithelial cell line RT112 as shown in Fig 1. These results further suggest that similar to the the P-, S-, and

A. Salam Khan; Jörg Hacker

329

Quantitative Metabolomics Reveals an Epigenetic Blueprint for Iron Acquisition in Uropathogenic Escherichia coli  

Microsoft Academic Search

Bacterial pathogens are frequently distinguished by the presence of acquired genes associated with iron acquisition. The presence of specific siderophore receptor genes, however, does not reliably predict activity of the complex protein assemblies involved in synthesis and transport of these secondary metabolites. Here, we have developed a novel quantitative metabolomic approach based on stable isotope dilution to compare the complement

Jeffrey P. Henderson; Jan R. Crowley; Jerome S. Pinkner; Jennifer N. Walker; Pablo Tsukayama; Walter E. Stamm; Thomas M. Hooton; Scott J. Hultgren

2009-01-01

330

Sources of Escherichia coli in a coastal subtropical environment.  

PubMed

Sources of Escherichia coli in a coastal waterway located in Ft. Lauderdale, Fla., were evaluated. The study consisted of an extensive program of field measurements designed to capture spatial and temporal variations in E. coli concentrations as well as experiments conducted under laboratory-controlled conditions. E. coli from environmental samples was enumerated by using a defined substrate technology (Colilert-18). Field sampling tasks included sampling the length of the North Fork to identify the river reach contributing high E. coli levels, autosampler experiments at two locations, and spatially intense sampling efforts at hot spots. Laboratory experiments were designed to simulate tidal conditions within the riverbank soils. The results showed that E. coli entered the river in a large pulse during storm conditions. After the storm, E. coli levels returned to baseline levels and varied in a cyclical pattern which correlated with tidal cycles. The highest concentrations were observed during high tide, whereas the lowest were observed at low tide. This peculiar pattern of E. coli concentrations between storm events was caused by the growth of E. coli within riverbank soils which were subsequently washed in during high tide. Laboratory analysis of soil collected from the riverbanks showed increases of several orders of magnitude in soil E. coli concentrations. The ability of E. coli to multiply in the soil was found to be a function of soil moisture content, presumably due to the ability of E. coli to outcompete predators in relatively dry soil. The importance of soil moisture in regulating the multiplication of E. coli was found to be critical in tidally influenced areas due to periodic wetting and drying of soils in contact with water bodies. Given the potential for growth in such systems, E. coli concentrations can be artificially elevated above that expected from fecal impacts alone. Such results challenge the use of E. coli as a suitable indicator of water quality in tidally influenced areas located within tropical and subtropical environments. PMID:10618229

Solo-Gabriele, H M; Wolfert, M A; Desmarais, T R; Palmer, C J

2000-01-01

331

Sources of Escherichia coli in a Coastal Subtropical Environment  

PubMed Central

Sources of Escherichia coli in a coastal waterway located in Ft. Lauderdale, Fla., were evaluated. The study consisted of an extensive program of field measurements designed to capture spatial and temporal variations in E. coli concentrations as well as experiments conducted under laboratory-controlled conditions. E. coli from environmental samples was enumerated by using a defined substrate technology (Colilert-18). Field sampling tasks included sampling the length of the North Fork to identify the river reach contributing high E. coli levels, autosampler experiments at two locations, and spatially intense sampling efforts at hot spots. Laboratory experiments were designed to simulate tidal conditions within the riverbank soils. The results showed that E. coli entered the river in a large pulse during storm conditions. After the storm, E. coli levels returned to baseline levels and varied in a cyclical pattern which correlated with tidal cycles. The highest concentrations were observed during high tide, whereas the lowest were observed at low tide. This peculiar pattern of E. coli concentrations between storm events was caused by the growth of E. coli within riverbank soils which were subsequently washed in during high tide. Laboratory analysis of soil collected from the riverbanks showed increases of several orders of magnitude in soil E. coli concentrations. The ability of E. coli to multiply in the soil was found to be a function of soil moisture content, presumably due to the ability of E. coli to outcompete predators in relatively dry soil. The importance of soil moisture in regulating the multiplication of E. coli was found to be critical in tidally influenced areas due to periodic wetting and drying of soils in contact with water bodies. Given the potential for growth in such systems, E. coli concentrations can be artificially elevated above that expected from fecal impacts alone. Such results challenge the use of E. coli as a suitable indicator of water quality in tidally influenced areas located within tropical and subtropical environments.

Solo-Gabriele, Helena M.; Wolfert, Melinda A.; Desmarais, Timothy R.; Palmer, Carol J.

2000-01-01

332

Genetic engineering of ethanol production in Escherichia coli  

SciTech Connect

The genes encoding essential enzymes of the fermentative pathway for ethanol production in Zymomonas mobilis, an obligately ethanologenic bacterium, were inserted into Escherichia coli under the control of a common promoter. Alcohol dehydrogenase II and pyruvate decarboxylase from Z. mobilis were expressed at high levels in E. coli, resulting in increased cell growth and the production of ethanol as the principal fermentation product from glucose. These results demonstrate that it is possible to change the fermentation products of an organism, such as E. coli, by the addition of genes encoding appropriate enzymes which form an alternative system for the regeneration of NAD/sup +/.

Ingram, L.O.; Conway, T.; Clark, D.P.; Sewell, G.W.; Preston, J.F.

1987-10-01

333

An integrated database to support research on Escherichia coli  

SciTech Connect

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.

Baehr, A.; Dunham, G.; Matsuda, Hideo; Michaels, G.; Taylor, R.; Overbeek, R.; Rudd, K.E. (National Inst. of Mental Health, Bethesda, MD (United States)); Ginsburg, A.; Joerg, D.; Kazic, T. (Washington Univ., St. Louis, MO (United States). Dept. of Genetics); Hagstrom, R.; Zawada, D. (Argonne National Lab., IL (United States)); Smith, C.; Yoshida, Kaoru (Lawrence Berkeley Lab., CA (United States))

1992-01-01

334

Virulence Potential and Genomic Mapping of the Worldwide Clone Escherichia coli ST131  

PubMed Central

Recently, the worldwide propagation of clonal CTX-M-15-producing Escherichia coli isolates, namely ST131 and O25b:H4, has been reported. Like the majority of extra-intestinal pathogenic E. coli isolates, the pandemic clone ST131 belongs to phylogenetic group B2, and has recently been shown to be highly virulent in a mouse model, even though it lacks several genes encoding key virulence factors (Pap, Cnf1 and HlyA). Using two animal models, Caenorhabditis elegans and zebrafish embryos, we assessed the virulence of three E. coli ST131 strains (2 CTX-M-15- producing urine and 1 non-ESBL-producing faecal isolate), comparing them with five non-ST131 B2 and a group A uropathogenic E. coli (UPEC). In C. elegans, the three ST131 strains showed intermediate virulence between the non virulent group A isolate and the virulent non-ST131 B2 strains. In zebrafish, the CTX-M-15-producing ST131 UPEC isolates were also less virulent than the non-ST131 B2 strains, suggesting that the production of CTX-M-15 is not correlated with enhanced virulence. Amongst the non-ST131 B2 group isolates, variation in pathogenic potential in zebrafish embryos was observed ranging from intermediate to highly virulent. Interestingly, the ST131 strains were equally persistent in surviving embryos as the non-ST131-group B2 strains, suggesting similar mechanisms may account for development of persistent infection. Optical maps of the genome of the ST131 strains were compared with those of 24 reference E. coli strains. Although small differences were seen within the ST131 strains, the tree built on the optical maps showed that these strains belonged to a specific cluster (86% similarity) with only 45% similarity with the other group B2 strains and 25% with strains of group A and D. Thus, the ST131 clone has a genetic composition that differs from other group B2 strains, and appears to be less virulent than previously suspected.

Goret, Lucie; Sotto, Albert; Combescure, Christophe; Blanco, Jorge; O'Callaghan, David; Nicolas-Chanoine, Marie-Helene

2012-01-01

335

Nonlethal Adherence to Human Neutrophils Mediated by Dr Antigen-Specific Adhesins ofEscherichia coli  

Microsoft Academic Search

UropathogenicEscherichia colistrains express a variety of adhesins, including members of the Dr adhesin family such as the Dr hemagglutinin, AFAI, and AFAIII. CertainE. coliadhesins (e.g., type 1 and Sfimbriae) are known to mediate adherence to human polymorphonuclear leukocytes (PMNs). The receptor on erythro- cytes for Dr family adhesins, decay accelerating factor, is also present on PMNs. To determine whether Dr

JAMES R. JOHNSON; KEITH M. SKUBITZ; BOGDAN J. NOWICKI; KAREN JACQUES-PALAZ; ANDROBERT M. RAKITA

336

Method 1103.1: Escherichia coli (E. coli) in Water by Membrane Filtration Using membrane-Thermotolerant Escherichia coli Agar (mTEC), April 2005.  

National Technical Information Service (NTIS)

Method 1103.1 describes a membrane filter (MF) procedure for the detection and enumeration of Escherichia coli bacteria in ambient water. E. coli is a common inhabitant of the intestinal tract of warm-blooded animals, and its presence in water samples is ...

2005-01-01

337

Genome Sequence of Enterotoxigenic Escherichia coli Strain B2C.  

PubMed

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. PMID:24723709

Madhavan, T P Vipin; Steen, Jason A; Hugenholtz, Philip; Sakellaris, Harry

2014-01-01

338

Induction of radioresistance in Escherichia coli. [X radiation, uv radiation  

Microsoft Academic Search

The effect of prior treatment by inducing agents on the radioresistance of cells of Escherichia coli has been studied. In order to separate the induction process from the radiation-damage process, cells were first treated with inducing agents such as ultraviolet light, ionizing radiation, or nalidixic acid, allowed to become induced by incubation for 50 min and then given rifampin to

E. C. Pollard; P. M. Achey

1975-01-01

339

Growth Moderation in Slow-growing Mutants of Escherichia coli  

Microsoft Academic Search

SUMMARY Mutants of Escherichia coli were induced by U.V. light and selected by the criterion that they formed small colonies on a nutrient agar at normal temperature. Nine slow-growing mutant strains were isolated. These mutants were characterized and compared during exponential growth in a nutrient medium with respect to doubling time, average cell mass, and DNA and RNA contents. The

C. N. NEWMAN; R. C. BOCK RATH

1974-01-01

340

Transmembrane glutathione cycling in growing Escherichia coli cells  

Microsoft Academic Search

Glutathione (GSH) plays an important role in bacterial cells, participating in maintenance of redox balance in the cytoplasm and in defense against many toxic compounds and stresses. In this study we demonstrate that in aerobic, exponentially growing Escherichia coli culture endogenous reduced glutathione undergoes continuous transmembrane cycling between the cells and medium. As a result of an establishment of a

Galina Smirnova; Nadezda Muzyka; Oleg Oktyabrsky

341

Anaerobic Growth Yields of Aerobacter cloacae and Escherichia coli  

PubMed Central

Aerobacter cloacae UW-C83 and Escherichia coli K-12 were grown under various anaerobic environments. Yatp values were calculated by determination of cell weights and analyses for fermentation products. These Yatp values are compared with others reported in the literature. Limitation of growth by factors other than adenosine triphosphate supply is discussed.

Hernandez, Eovaldo; Johnson, Marvin J.

1967-01-01

342

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...

343

Escherichia coli O104:H4 Infections and International Travel  

PubMed Central

We analyzed travel-associated clinical isolates of Escherichia coli O104:H4, including 1 from the 2011 German outbreak and 1 from a patient who returned from the Philippines in 2010, by genome sequencing and optical mapping. Despite extensive genomic similarity between these strains, key differences included the distribution of toxin and antimicrobial drug–resistance determinants.

Alexander, David C.; Hao, Weilong; Gilmour, Matthew W.; Zittermann, Sandra; Sarabia, Alicia; Melano, Roberto G.; Peralta, Analyn; Lombos, Marina; Warren, Keisha; Amatnieks, Yuri; Virey, Evangeline; Ma, Jennifer H.; Jamieson, Frances B.; Low, Donald E.

2012-01-01

344

The acetolactate synthase isoenzymes of Escherichia coli K-12  

Microsoft Academic Search

Strains of Escherichia coli K-12 possessing only one of the three genes coding for acetolactate synthetase activity present either in the wild type or in its ilv0603 derivative were prepared and analyzed. Extracts prepared from these strains show different values of acetolactate synthase specific activity and different sensitivity to valine inhibition. These strains show a unique pattern of growth inhibition

John Guardiola; Maurilio De Felice; Alessandro Lamberti; Maurizio Iaccarino

1977-01-01

345

Model for Bacteriophage T4 Development in Escherichia coli  

Microsoft Academic Search

Mathematical relations for the number of mature T4 bacteriophages, both inside and after lysis of an Escherichia coli cell, as a function of time after infection by a single phage were obtained, with the following five parameters: delay time until the first T4 is completed inside the bacterium (eclipse period, n) and its standard deviation (s), the rate at which

AVINOAM RABINOVITCH; HILLA HADAS; MONICA EINAV; ZEEV MELAMED

1999-01-01

346

Septicaemia caused by cysteine-requiring isolates of Escherichia coli  

Microsoft Academic Search

Summary. The clinical and bacteriological findings in five cases of septicaemia with cysteine-requiring isolates of Escherichia coli are reported. Infections with these nutritionally-dependent organisms have been found previously in the urinary tract only, associated usually with chronic rather than acute conditions. The urinary tract was considered to be the source of the septicaemia in our patients and that site should

J. W. TAPSALL; C. J. McIVER

1986-01-01

347

Enteropathogenic Escherichia coli and life threatening chronic diarrhoea  

Microsoft Academic Search

Enteropathogenic Escherichia coli (EPEC) infection is not generally thought to cause severe diarrhoea after the neonatal period. Patients admitted to Queen Elizabeth Hospital for Children over the three years (1984-7) with diarrhoea and EPEC infection were reviewed. Clinical details, features of small intestinal mucosa, and treatment were recorded in those who developed chronic diarrhoea with failure to thrive. Twenty six

S M Hill; A D Phillips; J A Walker-Smith

1991-01-01

348

The Kinetics of the Mating Process in Escherichia coli  

Microsoft Academic Search

SUMMARY: When broth cultures of donor (HfrH) and recipient (F-) strains of Escherichia coli K-12 are mixed, zygotes are formed by the transfer of part of the donor chromosome to the recipient cell. The donor parent thus becomes dispensable as soon as transfer is accomplished. The kinetics of zygote formation can therefore be studied by treating samples, removed at intervals

W. HAYES

1957-01-01

349

Colonization factors of human enterotoxigenic Escherichia coli (ETEC)  

Microsoft Academic Search

Enterotoxigenic Escherichia coli (ETEC) is the most common cause of childhood and traveller's diarrhoea. The ability of ETEC to adhere to the intestinal epithelium of the host is an important virulence determinant, and adhesion is mediated by proteinaceous surface appendages called colonization factors.

Wim Gaastra; Ann-Mari Svennerholm

1996-01-01

350

rRNA transcription rate in Escherichia coli.  

PubMed Central

The rate of in vivo transcription elongation for Escherichia coli rRNA operons was determined by electron microscopy following addition of rifampin to log-phase cultures. Direct observation of RNA polymerase positions along rRNA operons 30, 40, and 70 s after inhibition of transcription initiation yielded a transcription elongation rate of 42 nucleotides per s. Images FIG. 1

Gotta, S L; Miller, O L; French, S L

1991-01-01

351

Enteropathogenic and Enterohemorrhagic Escherichia coli Infections: Translocation, Translocation, Translocation  

Microsoft Academic Search

Escherichia coli is the most abundant facultative anaerobic gram-negative bacterium of the intestinal microflora, naturally colonizing the mucous layer of the colon. A conserved core genomic structure is common to both commensal and patho- genic strains, providing the microorganisms with mechanisms required for survival under the competitive conditions in the gut, as well as the ability to spread among hosts

Junkal Garmendia; Gad Frankel; Valerie F. Crepin

2005-01-01

352

Catabolite repression in Escherichia coli mutants lacking cyclic AMP  

Microsoft Academic Search

The regulation of catabolite repression of ß-galactosidase has been studied in Escherichia coli mutants deleted for the adenyl cyclase gene (cya?), and thus unable to synthesize cyclic AMP. It has been found that, provided a second mutation occurs either in the crp gene coding for the catabolite gene activator protein (CAP) or in the Lactose region, these mutants exhibit catabolite

Alain Dessein; Maxime Schwartz; Agnčs Ullmann

1978-01-01

353

Expression of active, human lysyl oxidase in Escherichia coli  

Microsoft Academic Search

Lysyl oxidase (LO) is a copper amine oxidase of the extracellular matrix which initiates covalent cross-linking in collagens and elastin. Human LO was expressed in Escherichia coli. At 37°C, large amounts of protein were obtained, but in the form of insoluble aggregates. Lowering the growth temperature, and reducing the amount of inducer, resulted in the production of soluble LO, which

M. Ouzzine; A. Boyd; D. J. S. Hulmes

1996-01-01

354

Pyrroloquinoline quinone, a chemotactic attractant for Escherichia coli.  

PubMed Central

Escherichia coli is attracted by pyrroloquinoline quinone (PQQ), and chemotaxis toward glucose is enhanced by the presence of PQQ. A ptsI mutant showed no chemotactic response to either glucose or PQQ alone but did show a chemotactic response to a mixture of glucose and PQQ. A strain lacking the methylated chemotaxis receptor protein Tar showed no response to PQQ.

de Jonge, R; Teixeira de Mattos, M J; Stock, J B; Neijssel, O M

1996-01-01

355

Virulence of Escherichia Coli Strains for Chick Embryos.  

National Technical Information Service (NTIS)

Fifty-three strains of Escherichia coli, freshly isolated from patients at Children's Hospital, Washington, D. C., were tested for virulence for 13-day chick embryos by allantoic inoculation of serial dilutions of viable cell suspensions. No clear-cut rel...

C. J. Powell R. A. Finkelstein

1965-01-01

356

Molecular basis of base substitution hotspots in Escherichia coli  

Microsoft Academic Search

In the lacI gene of Escherichia coli spontaneous base substitution hotspots occur at 5-methylcytosine residues. The hotspots disappear when the respective cytosines are not methylated. We suggest that the hotspots may result from the spontaneous deamination of 5-methylcytosine to thymine, which is not excised by the enzyme DNA-uracil glycosidase.

Christine Coulondre; Jeffrey H. Miller; Philip J. Farabaugh; Walter Gilbert

1978-01-01

357

In search of the minimal Escherichia coli genome  

Microsoft Academic Search

Recent plans announced for the systematic cataloging of the minimal Escherichia coli gene set, the pheno- types of all mutations, the expression levels of every transcript and gene product, and the interactions of all genetic loci or their gene products point the way towards a new frontier in the biology of model organ- isms. Powerful tools for this endeavor are

Darren J. Smalley; Marvin Whiteley; Tyrrell Conway

2002-01-01

358

Persistence of colicinogenic Escherichia coli in the mouse gastrointestinal tract  

Microsoft Academic Search

BACKGROUND: The ability of a bacterial strain to competitively exclude or displace other strains can be attributed to the production of narrow spectrum antimicrobials, the bacteriocins. In an attempt to evaluate the importance of bacteriocin production for Escherichia coli strain residence in the gastrointestinal tract, a murine model experimental evolution study was undertaken. RESULTS: Six colicin-producing, yet otherwise isogenic, E.

Osnat Gillor; Itamar Giladi; Margaret A Riley

2009-01-01

359

Alteration of Escherichia coli Topoisomerase IV to Novobiocin Resistance  

Microsoft Academic Search

DNA gyrase and topoisomerase IV (topo IV) are the two essential type II topoisomerases of Escherichia coli. Gyrase is responsible for maintaining negative supercoiling of the bacterial chromosome, whereas topo IV's primary role is in disentangling daughter chromosomes following DNA replication. Coumarins, such as novobiocin, are wide-spectrum antimicrobial agents that primarily interfere with DNA gyrase. In this work we designed

Christine D. Hardy; Nicholas R. Cozzarelli

2003-01-01

360

Enterotoxigenic Escherichia-coli-associated diarrheal disease in Apache children.  

PubMed

A search for intestinal enterotoxigenic Escherichia coli was made in 59 Apache children hospitalized with 64 episodes of acute diarrhea. Esch. coli isolates from acute-phase and convalescent-phase specimens of small-bowel fluid and stool were tested in three currently recognized models: the adult-rabbit ileal loop; infant rabbit; and the adrenal-cell assay. Enterotoxigenic strains were isolated from 10 children during acute diarrheal episodes (16 per cent); none were isolated from convalescent-phase specimens. None of 64 "enteropathogenic" serotypes of Esch. coli from 43 children with diarrhea, however, caused fluid production in the ileal-loop model. These results suggest that enterotoxigenic Esch. coli may be the cause of considerable diarrhea in this population and that the term "enteropathogenic" as applied to serotypes of Esch. coli needs to be redefined. PMID:1091855

Sack, R B; Hirschhorn, N; Brownlee, I; Cash, R A; Woodward, W E; Sack, D A

1975-05-15

361

Sex and virulence in Escherichia coli: an evolutionary perspective.  

PubMed

Pathogenic Escherichia coli cause over 160 million cases of dysentery and one million deaths per year, whereas non-pathogenic E. coli constitute part of the normal intestinal flora of healthy mammals and birds. The evolutionary pathways underlying this dichotomy in bacterial lifestyle were investigated by multilocus sequence typing of a global collection of isolates. Specific pathogen types [enterohaemorrhagic E. coli, enteropathogenic E. coli, enteroinvasive E. coli, K1 and Shigella] have arisen independently and repeatedly in several lineages, whereas other lineages contain only few pathogens. Rates of evolution have accelerated in pathogenic lineages, culminating in highly virulent organisms whose genomic contents are altered frequently by increased rates of homologous recombination; thus, the evolution of virulence is linked to bacterial sex. This long-term pattern of evolution was observed in genes distributed throughout the genome, and thereby is the likely result of episodic selection for strains that can escape the host immune response. PMID:16689791

Wirth, Thierry; Falush, Daniel; Lan, Ruiting; Colles, Frances; Mensa, Patience; Wieler, Lothar H; Karch, Helge; Reeves, Peter R; Maiden, Martin C J; Ochman, Howard; Achtman, Mark

2006-06-01

362

Degradation of Abnormal Proteins in 'Escherichia coli'.  

National Technical Information Service (NTIS)

Evidence is presented that E. coli contains a mechanism for selective degradation of abnormal proteins. Unfinished polypeptides containing puromycin, proteins containing frequent errors in translation, such as those synthesized by strains containing a ram...

A. L. Goldberg

1971-01-01

363

Use of DNA Probes and HEp-2 Cell Adherence Assay to Detect Diarrheagenic Escherichia coli. (Reannouncement with New Availability Information).  

National Technical Information Service (NTIS)

Four major categories of Escherichia coli are recognized as causes of diarrheal disease, including enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC), enteroinvasive E. coli (EIEC), and enterohemorrhagic E. coli (EHEC); each category comprise...

M. M. Levine V. Prado R. Robins-Browne H. Lior J. B. Kaper

1988-01-01

364

Experimental Escherichia coli O157:H7 carriage in calves.  

PubMed Central

Nine weaned calves (6 to 8 weeks of age) were given 10(10) CFU of a five-strain mixture of enterohemorrhagic Escherichia coli O157:H7 by oral-gastric intubation. After an initial brief period of pyrexia in three calves and transient mild diarrhea in five calves, calves were clinically normal throughout the 13- to 27-day study. The population of E. coli O157:H7 in the faces decreased dramatically in all calves during the first 2 weeks after inoculation. Thereafter, small populations of E. coli O157:H7 persisted in all calves, where they were detected intermittently in the feces and rumen contents. While withholding food increased fecal shedding of E. coli O157:H7 by 1 to 2 log10/g in three of four calves previously shedding small populations of E. coli O157:H7, the effect of fasting on fecal shedding of E. coli O157:H7 was variable in calves shedding larger populations. At necropsy, E. coli O157:H7 was not isolated from sites outside the alimentary tract. E. coli O157:H7 was isolated from the forestomach or colon of all calves at necropsy. Greater numbers of E. coli O157:H7 were present in the gastrointestinal contents than in the corresponding mucosal sections, and there was no histologic or immunohistochemical evidence of E. coli O157:H7 adhering to the mucosa. In conclusion, under these experimental conditions, E. coli O157:H7 is not pathogenic in weaned calves, and while it does not appear to colonize mucosal surfaces for extended periods, E. coli O157:H7 persists in the contents of the rumen and colon as a source for fecal shedding.

Brown, C A; Harmon, B G; Zhao, T; Doyle, M P

1997-01-01

365

Lytic bacteriophages reduce Escherichia coli O157  

PubMed Central

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 ?g/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.

Ferguson, Sean; Roberts, Cheryl; Handy, Eric; Sharma, Manan

2013-01-01

366

Adhesion of Human and Animal Escherichia coli Strains in Association with Their Virulence-Associated Genes and Phylogenetic Origins  

PubMed Central

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.

Frommel, Ulrike; Lehmann, Werner; Rodiger, Stefan; Bohm, Alexander; Nitschke, Jorg; Weinreich, Jorg; Gross, Julia; Roggenbuck, Dirk; Zinke, Olaf; Ansorge, Hermann; Vogel, Steffen; Klemm, Per; Wex, Thomas; Schroder, Christian; Wieler, Lothar H.

2013-01-01

367

Novel phage-based bio-processing of pathogenic Escherichia coli and its biofilms  

Microsoft Academic Search

To explore new approaches of phage-based bio-process of specifically pathogenic Escherichia coli bacteria in food products within a short period. One hundred and forty highly lytic designed coliphages were used. Escherichia coli naturally contaminated and Enterohemorrhagic Escherichia coli experimentally inoculated samples of lettuce, cabbage, meat, and egg were used. In addition, experimentally produced biofilms\\u000a of E. coli were tested. A

S. A. A. Jassim; A. S. Abdulamir; F. Abu Bakar

368

Multidimensional annotation of the Escherichia coli K-12 genome  

PubMed Central

The annotation of the Escherichia coli K-12 genome in the EcoCyc database is one of the most accurate, complete and multidimensional genome annotations. Of the 4460 E. coli genes, EcoCyc assigns biochemical functions to 76%, and 66% of all genes had their functions determined experimentally. EcoCyc assigns E. coli genes to Gene Ontology and to MultiFun. Seventy-five percent of gene products contain reviews authored by the EcoCyc project that summarize the experimental literature about the gene product. EcoCyc information was derived from 15 000 publications. The database contains extensive descriptions of E. coli cellular networks, describing its metabolic, transport and transcriptional regulatory processes. A comparison to genome annotations for other model organisms shows that the E. coli genome contains the most experimentally determined gene functions in both relative and absolute terms: 2941 (66%) for E. coli, 2319 (37%) for Saccharomyces cerevisiae, 1816 (5%) for Arabidopsis thaliana, 1456 (4%) for Mus musculus and 614 (4%) for Drosophila melanogaster. Database queries to EcoCyc survey the global properties of E. coli cellular networks and illuminate the extent of information gaps for E. coli, such as dead-end metabolites. EcoCyc provides a genome browser with novel properties, and a novel interactive display of transcriptional regulatory networks.

Karp, Peter D.; Keseler, Ingrid M.; Shearer, Alexander; Latendresse, Mario; Krummenacker, Markus; Paley, Suzanne M.; Paulsen, Ian; Collado-Vides, Julio; Gama-Castro, Socorro; Peralta-Gil, Martin; Santos-Zavaleta, Alberto; Penaloza-Spinola, Monica I.; Bonavides-Martinez, Cesar; Ingraham, John

2007-01-01

369

Food Reservoir for Escherichia coli Causing Urinary Tract Infections  

PubMed Central

Closely related strains of Escherichia coli have been shown to cause extraintestinal infections in unrelated persons. This study tests whether a food reservoir may exist for these E. coli. Isolates from 3 sources over the same time period (2005–2007) and geographic area were compared. The sources comprised prospectively collected E. coli isolates from women with urinary tract infection (UTI) (n = 353); retail meat (n = 417); and restaurant/ready-to-eat foods (n = 74). E. coli were evaluated for antimicrobial drug susceptibility and O:H serotype and compared by using 4 different genotyping methods. We identified 17 clonal groups that contained E. coli isolates (n = 72) from >1 source. E. coli from retail chicken (O25:H4-ST131 and O114:H4-ST117) and honeydew melon (O2:H7-ST95) were indistinguishable from or closely related to E. coli from human UTIs. This study provides strong support for the role of food reservoirs or foodborne transmission in the dissemination of E. coli causing common community-acquired UTIs.

Vincent, Caroline; Boerlin, Patrick; Daignault, Danielle; Dozois, Charles M.; Dutil, Lucie; Galanakis, Chrissi; Reid-Smith, Richard J.; Tellier, Pierre-Paul; Tellis, Patricia A.; Ziebell, Kim

2010-01-01

370

Enhancing the antibiotic antibacterial effect by sub lethal tellurite concentrations: tellurite and cefotaxime act synergistically in Escherichia coli.  

PubMed

The emergence of antibiotic-resistant pathogenic bacteria during the last decades has become a public health concern worldwide. Aiming to explore new alternatives to treat antibiotic-resistant bacteria and given that the tellurium oxyanion tellurite is highly toxic for most microorganisms, we evaluated the ability of sub lethal tellurite concentrations to strengthen the effect of several antibiotics. Tellurite, at nM or µM concentrations, increased importantly the toxicity of defined antibacterials. This was observed with both gram negative and gram positive bacteria, irrespective of the antibiotic or tellurite tolerance of the particular microorganism. The tellurite-mediated antibiotic-potentiating effect occurs in laboratory and clinical, uropathogenic Escherichia coli, especially with antibiotics disturbing the cell wall (ampicillin, cefotaxime) or protein synthesis (tetracycline, chloramphenicol, gentamicin). In particular, the effect of tellurite on the activity of the clinically-relevant, third-generation cephalosporin (cefotaxime), was evaluated. Cell viability assays showed that tellurite and cefotaxime act synergistically against E. coli. In conclusion, using tellurite like an adjuvant could be of great help to cope with several multi-resistant pathogens. PMID:22536386

Molina-Quiroz, Roberto C; Muńoz-Villagrán, Claudia M; de la Torre, Erick; Tantaleán, Juan C; Vásquez, Claudio C; Pérez-Donoso, José M

2012-01-01

371

Enhancing the Antibiotic Antibacterial Effect by Sub Lethal Tellurite Concentrations: Tellurite and Cefotaxime Act Synergistically in Escherichia coli  

PubMed Central

The emergence of antibiotic-resistant pathogenic bacteria during the last decades has become a public health concern worldwide. Aiming to explore new alternatives to treat antibiotic-resistant bacteria and given that the tellurium oxyanion tellurite is highly toxic for most microorganisms, we evaluated the ability of sub lethal tellurite concentrations to strengthen the effect of several antibiotics. Tellurite, at nM or µM concentrations, increased importantly the toxicity of defined antibacterials. This was observed with both Gram negative and Gram positive bacteria, irrespective of the antibiotic or tellurite tolerance of the particular microorganism. The tellurite-mediated antibiotic-potentiating effect occurs in laboratory and clinical, uropathogenic Escherichia coli, especially with antibiotics disturbing the cell wall (ampicillin, cefotaxime) or protein synthesis (tetracycline, chloramphenicol, gentamicin). In particular, the effect of tellurite on the activity of the clinically-relevant, third-generation cephalosporin (cefotaxime), was evaluated. Cell viability assays showed that tellurite and cefotaxime act synergistically against E. coli. In conclusion, using tellurite like an adjuvant could be of great help to cope with several multi-resistant pathogens.

Molina-Quiroz, Roberto C.; Munoz-Villagran, Claudia M.; de la Torre, Erick; Tantalean, Juan C.; Vasquez, Claudio C.; Perez-Donoso, Jose M.

2012-01-01

372

EcoCyc: Enyclopedia of Escherichia coli Genes and Metabolism.  

PubMed Central

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.

Karp, P D; Riley, M; Paley, S M; Pellegrini-Toole, A; Krummenacker, M

1997-01-01

373

EcoCyc: Enyclopedia of Escherichia coli Genes and Metabolism.  

PubMed

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

Karp, P D; Riley, M; Paley, S M; Pellegrini-Toole, A; Krummenacker, M

1997-01-01

374

Eco Cyc: encyclopedia of Escherichia coli genes and metabolism.  

PubMed

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/ PMID:9847140

Karp, P D; Riley, M; Paley, S M; Pellegrini-Toole, A; Krummenacker, M

1999-01-01

375

Inhibition of Escherichia coli-Induced Meningitis by Carboxyfullerence  

PubMed Central

The effect of a water-soluble malonic acid derivative of carboxyfullerence (C60) against Escherichia coli-induced meningitis was tested. C60 can protect the mice from E. coli-induced death in a dose-dependent manner. C60 administered intraperitoneally as late as 9 h after E. coli injection was still protective. The C60-treated mice had less tumor necrosis factor alpha and interleukin-1? production by staining of brain tissue compared to the levels of production for nontreated mice. The E. coli-induced increases in blood-brain barrier permeability and inflammatory neutrophilic infiltration were also inhibited. These data suggest that C60 is a potentially therapeutic agent for bacterial meningitis.

Tsao, Nina; Kanakamma, Puthuparampil P.; Luh, Tien-Yau; Chou, Chen-Kung; Lei, Huan-Yao

1999-01-01

376

Production of 5-Methlthioribose by 'Escherichia coli.'.  

National Technical Information Service (NTIS)

A study of sulfur metabolism in micro-organisms led to the isolation and identification of 5-methylthioribose (MTR) from E. coli B. MTR labeled with 35S was excreted by the bacterium during incubation in glucose-salts medium supplemented with 35SO4(-2). I...

M. F. Mallette

1972-01-01

377

Evaluation of Multiplex PCRs for Diagnosis of Infection with Diarrheagenic Escherichia coli and Shigella spp  

Microsoft Academic Search

Received 13 January 2004\\/Returned for modification 3 March 2004\\/Accepted 3 August 2004 We have developed two multiplex PCR assays that detect typical and atypical enteropathogenic Escherichia coli (EPEC) isolates, enteroaggregative E. coli (EAEC) isolates, enterotoxigenic E. coli (ETEC) isolates, enteroinvasive E. coli (EIEC) isolates, Shiga toxin-producing E. coli (STEC) isolates, and Shigella spp. The targets selected for each group were

K. R. S. Aranda; U. Fagundes-Neto; I. C. A. Scaletsky

2004-01-01

378

Effect of Escherichia coli enterotoxins on macromolecular absorption.  

PubMed Central

Macromolecular absorption of gliadin, a wheat protein and alpha lactalbumin, a milk protein was evaluated in control and Escherichia coli enterotoxin (heat-stable, heat-labile, and both heat-stable and heat-labile enterotoxin) treated mice. The peak concentration of gliadin and lactalbumin was two hours and three hours after their ingestion, respectively. There was also a significant increase (p < 0.01) in the absorption of both the proteins in all the three toxin treated groups compared with the control group. These results suggest that intestinal permeability and macromolecular absorption changes after E coli infection.

Verma, M; Majumdar, S; Ganguly, N K; Walia, B N

1994-01-01

379

Sodium-Stimulated Transport of Glutamate in Escherichia coli  

PubMed Central

Wild-type Escherichia coli B grew poorly on glutamate as the sole carbon source, except at very high concentrations of the amino acid. The addition of sodium ion markedly stimulated the growth. It had the same effect in a mutant of E. coli B selected for the ability to grow at low glutamate concentrations. Sodium ion also potentiated growth inhibition by analogues of glutamate. The uptake of glutamate by nongrowing cells of the mutant was markedly stimulated by sodium ion in the presence of an energy source, chloramphenicol, and arsenite, which retarded glutamate degradation.

Frank, Leonard; Hopkins, Irene

1969-01-01

380

Recombinant protein expression in Escherichia coli: advances and challenges  

PubMed Central

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.

Rosano, German L.; Ceccarelli, Eduardo A.

2014-01-01

381

Accelerated glycerol fermentation in Escherichia coli using methanogenic formate consumption.  

PubMed

Escherichia coli can ferment glycerol anaerobically only under very defined restrictive conditions. Hence, it was the aim of this study to overcome this limitation via a co-cultivation approach. Anaerobic glycerol fermentation by a pure E. coli culture was compared to a co-culture that also contained the formate-oxidizing methanogen Methanobacterium formicicum. Co-cultivation of the two strains led to a more than 11-fold increased glycerol consumption. Furthermore, it supported a constantly neutral pH and a shift from ethanol to succinate production. Moreover, M. formicicum was analyzed for its ability to grow on different standard media and a surprising versatility could be demonstrated. PMID:24785787

Richter, Katrin; Gescher, Johannes

2014-06-01

382

A signal transducer for aerotaxis in Escherichia coli.  

PubMed Central

The newly discovered aer locus of Escherichia coli encodes a 506-residue protein with an N terminus that resembles the NifL aerosensor and a C terminus that resembles the flagellar signaling domain of methyl-accepting chemoreceptors. Deletion mutants lacking a functional Aer protein failed to congregate around air bubbles or follow oxygen gradients in soft agar plates. Membranes with overexpressed Aer protein also contained high levels of noncovalently associated flavin adenine dinucleotide (FAD). We propose that Aer is a flavoprotein that mediates positive aerotactic responses in E. coli. Aer may use its FAD prosthetic group as a cellular redox sensor to monitor environmental oxygen levels.

Bibikov, S I; Biran, R; Rudd, K E; Parkinson, J S

1997-01-01

383

Catalase-negative Escherichia coli isolated from blood.  

PubMed Central

A catalase-negative variant of Escherichia coli was isolated from the blood of a patient with acute leukemia who had been treated with various antibiotics and gentamicin. This small-colony variant grew almost as actively under anaerobic conditions as its large-colony revertant or E. coli NIHJ JC-2. The variant was resistant to gentamicin, in contrast with the revertant. Streptomycin and hemin stimulated growth of the variant slightly. With repeated subculturing the variant tended to increase slightly in colony size with coincident recovery of weak catalase production. The possibility that such a variant may have been induced by gentamicin was indicated. Images

Funada, H; Hattori, K I; Kosakai, N

1978-01-01

384

Filamentation by Escherichia coli subverts innate defenses during urinary tract infection  

PubMed Central

To establish disease, an infecting organism must overcome a vast array of host defenses. During cystitis, uropathogenic Escherichia coli (UPEC) subvert innate defenses by invading superficial umbrella cells and rapidly increasing in numbers to form intracellular bacterial communities (IBCs). In the late stages of the IBC pathway, filamentous and bacillary UPEC detach from the biofilm-like IBC, fluxing out of this safe haven to colonize the surrounding epithelium and initiate subsequent generations of IBCs, and eventually they establish a quiescent intracellular reservoir. Filamentous UPEC are not observed during acute infection in mice lacking functional Toll-like receptor 4 (TLR4), suggesting that the filamentous phenotype arises in response to host innate immunity. We investigated SulA, a cell division inhibitor associated with the SOS response, to gain insight into the role of filamentous UPEC in pathogenesis. A transcriptional reporter from PsulA revealed spatial and temporal differences in expression within IBCs, and it was active in the majority of filamentous UPEC. Although UTI89 and UTI89 ?sulA both formed first-generation IBCs equally well, UTI89 ?sulA was sharply attenuated in formation of second-generation IBCs and establishment of the quiescent intracellular reservoir. The virulence of UTI89 ?sulA was restored in TLR4-deficient mice, suggesting that filamentation facilitates the transition to additional rounds of IBC formation by subverting innate immune responses. These findings demonstrate that transient SulA-mediated inhibition of cell division is essential for UPEC virulence in the murine model of cystitis.

Justice, Sheryl S.; Hunstad, David A.; Seed, Patrick C.; Hultgren, Scott J.

2006-01-01

385

Acs is essential for propionate utilization in Escherichia coli.  

PubMed

Bacteria like Escherichia coli can use propionate as sole carbon and energy source. All pathways for degradation of propionate start with propionyl-CoA. However, pathways of propionyl-CoA synthesis from propionate and their regulation mechanisms have not been carefully examined in E. coli. In this study, roles of the acetyl-CoA synthetase encoding gene acs and the NAD(+)-dependent protein deacetylase encoding gene cobB on propionate utilization in E. coli were investigated. Results from biochemical analysis showed that, reversible acetylation also modulates the propionyl-CoA synthetase activity of Acs. Subsequent genetic analysis revealed that, deletion of acs in E. coli results in blockage of propionate utilization, suggesting that acs is essential for propionate utilization in E. coli. Besides, deletion of cobB in E. coli also results in growth defect, but only under lower concentrations of propionate (5mM and 10mM propionate), suggesting the existence of other propionyl-CoA synthesis pathways. In combination with previous observations, our data implies that, for propionate utilization in E. coli, a primary amount of propionyl-CoA seems to be required, which is synthesized by Acs. PMID:24835953

Liu, Fengying; Gu, Jing; Wang, Xude; Zhang, Xian-En; Deng, Jiaoyu

2014-07-01

386

Erosion and Subsequent Transport State of Escherichia coli from Cowpats  

PubMed Central

Processes by which fecal bacteria enter overland flow and their transportation state to surface waters are poorly understood, making the effectiveness of measures designed to intercept this pathway, such as vegetated buffer strips, difficult to predict. Freshly made and aged (up to 30 days) cowpats were exposed to simulated rainfall, and samples of the cowpat material and runoff were collected. Escherichia coli in the runoff samples were separated into attached (to particles) and unattached fractions, and the unattached fraction was analyzed to determine if the cells were clumped. Within cowpats, E. coli grew for 6 to 14 days, rather than following a typical logarithmic die-off curve. E. coli numbers in the runoff correlated with numbers inside the cowpat. Most of the E. coli organisms eroded from the cowpats were transported as single cells, and only a small percentage (about 8%) attached to particles. The erosion of E. coli from cowpats and the state in which the cells were transported did not vary with time within a single rainfall event or over time as the cowpats aged and dried out. These findings indicate that cowpats can remain a significant source of E. coli in overland flow for more than 30 days. As well, most of the E. coli organisms eroded from cowpats will occur as readily transportable single cells.

Muirhead, Richard William; Collins, Robert Peter; Bremer, Philip James

2005-01-01

387

Pathotyping blaCTX-M Escherichia coli from Nigeria  

PubMed Central

Background: Escherichia coli have become the enterobacteriaceae species most affected by extended-spectrum ?-lactamases (ESBLs) in view of the emergence of CTX-M-type ESBLs. These CTX-M-positive E. coli have been reported in numerous regions worldwide. Virulence determinants of already reported CTX-M-positive E. coli were investigated. Methodology: To gain insights into the mechanism underlying this phenomenon, we assessed serogroup, susceptibility pattern and diversity of virulence profiles within a collection of nine blaCTX-M-positive E. coli strains and their virulent determinant using miniaturized DNA microarray techniques. The nine ESBL-positive E. coli isolates were from eight male and one female patient(s) selected for study based on previous work. Virulence potential was inferred by detection of 63 virulence factor (VF) genes. Results: Four (44.4%) of the 9 E. coli isolates exhibited the same set of core characteristics: serotype O8:Hnt, while all were positive for OXA-1, ciprofloxacin resistance. Five of the isolates exhibited highly similar (91% to 100%) VF profiles. Conclusion: The findings describe a broadly disseminated, blaCTX-M-positive and virulent E. coli serogroup with highly homogeneous virulence genotypes, suggesting recent emergence in this zone. Understanding how this clone has emerged and successfully disseminated within the hospital and community, including across national boundaries, should be a public health priority.

Olowe, Olugbenga Adekunle; Choudhary, Suman; Schierack, Peter; Wieler, Lothar H.; Olayemi, Albert B.; Anjum, Muna

2013-01-01

388

Compilation of DNA sequences of Escherichia coli  

PubMed Central

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.

Kroger, Manfred

1989-01-01

389

Enteropathogenic Escherichia coli Prevalence in Laboratory Rabbits  

PubMed Central

Rabbit-origin enteropathogenic E. coli (EPEC) causes substantial diarrhea-associated morbidity and has zoonotic potential. A culture-based survey was undertaken to ascertain its prevalence. EPEC was isolated from 6/141 (4.3%) commercially-acquired laboratory rabbits. Three of these did not have diarrhea or EPEC-typical intestinal lesions; they instead had background plasmacytic intestinal inflammation. Asymptomatically infected rabbits may function as EPEC reservoirs.

Swennes, Alton G.; Buckley, Ellen M.; Madden, Carolyn M.; Byrd, Charles P.; Donocoff, Rachel S.; Rodriguez, Loretta; Parry, Nicola M. A.; Fox, James G.

2013-01-01

390

Use of Genetically Engineered Escherichia coli to Monitor Ingestion, Loss, and Transfer of Bacteria in Termites  

Microsoft Academic Search

Escherichia coli was transformed with a recombinant plasmid (pEGFP) containing the genes for ampicillin resistance and Green Fluorescent Protein (GFP). Escherichia coli expressing GFP ( E. coli\\/GFP+) was then fed to workers of the termite Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). The transformed bacteria in the termite guts were detected by growing the gut flora under selective conditions and then checking

C. Husseneder; J. K. Grace; D. E. Oishi

2005-01-01

391

Demonstration of enterotoxigenic Escherichia coli in diarrheic broiler chicks.  

PubMed

An investigation was made to survey the possible presence of enterotoxigenic Escherichia coli (ETEC) in the stools of diarrheal chicks. We analyzed two outbreaks of diarrhea in broiler chicks at two independent farms in the Philippines, from which no pathogens other than Escherichia coli were found. In one outbreak at Farm #1, all 42 isolates produced heat-labile enterotoxin (LT), with 3 of these isolates also producing heat-stable enterotoxin (ST). The O serotypes of 15 strains tested randomly could not be identified as any known serotype (0-antigen; 1-170). In another outbreak at Farm #2, 7 out of 52 isolates produced only LT, their subtypes being identified as O-149 or O-8, common serotypes in pig ETEC. Strains from Farm #1 did not produce any pili usually found in human ETEC. We believe this to be the first isolation of ETEC from diarrheal chicks. PMID:2188851

Joya, J E; Tsuji, T; Jacalne, A V; Arita, M; Tsukamoto, T; Honda, T; Miwatani, T

1990-03-01

392

Enterotoxigenic Escherichia coli infection in captive black-footed ferrets.  

PubMed

Enterotoxigenic Escherichia coli with genes for heat stabile toxins Sta and STb was isolated from the gastrointestinal tract and multiple visceral organs of three adult and three juvenile black-footed ferrets (Mustela nigripes) that died in a captive breeding colony between 24 May 1998 and 2 July 1998. Similar isolates were obtained from rectal swabs of one adult and one juvenile that were clinically ill. All were fed a diet composed of mink chow, raw rabbit meat, beef liver powder, blood meal and lard. Escherichia coli of the same toxin genotype was isolated from the mixed ration. Clinical signs included sudden death, dehydration, anorexia and diarrhea. Necropsy lesions included acute enteritis with large numbers of rod shaped bacteria microscopically visible on intestinal villi. PMID:11504237

Bradley, G A; Orr, K; Reggiardo, C; Glock, R D

2001-07-01

393

Regulatory network of acid resistance genes in Escherichia coli  

Microsoft Academic Search

Summary Overexpression of the response regulator EvgA con- fers an acid-resistant phenotype to exponentially growing Escherichia coli . This acid resistance is par- tially abolished by deletion of ydeP , yhiE or ydeO , genes induced by EvgA overexpression. Microarray analysis identified two classes of operons (genes). The first class contains seven operons induced by EvgA overexpression in the absence

Nobuhisa Masuda; George M. Church

2003-01-01

394

Hydrogen Peroxide Fluxes and Compartmentalization inside Growing Escherichia coli  

Microsoft Academic Search

Escherichia coli generates about 14 M hydrogen peroxide (H2O2) per s when it grows exponentially in glucose medium. The steady-state intracellular concentration of H2O2 depends on the rates at which this H2O2 is dissipated by scavenging enzymes and by efflux from the cell. The rates of H2O2 degradation by the two major scavenging enzymes, alkyl hydroperoxide reductase and catalase, were

LAUREN COSTA SEAVER; JAMES A. IMLAY

2001-01-01

395

Endonuclease IV of Escherichia coli is Induced by Paraquat  

Microsoft Academic Search

The addition of paraquat (methyl viologen) to a growing culture of Escherichia coli K-12 led within 1 hr to a 10- to 20-fold increase in the level of endonuclease IV, a DNase for apurinic\\/apyrimidinic sites. The induction was blocked by chloramphenicol. Increases of 3-fold or more were also seen with plumbagin, menadione, and phenazine methosulfate. H2O2 produced no more than

Emily Chan; Bernard Weiss

1987-01-01

396

Mechanisms Accounting for Fluoroquinolone Resistance in Escherichia coli Clinical Isolates  

Microsoft Academic Search

Fluoroquinolone MICs are increased through the acquisition of chromosomal mutations in the genes encoding gyrase (gyrA and gyrB) and topoisomerase IV (parC and parE), increased levels of the multidrug efflux pump AcrAB, and the plasmid-borne genes aac(6)-Ib-cr and the qnr variants in Escherichia coli .I n the accompanying report, we found that ciprofloxacin, gatifloxacin, levofloxacin, and norfloxacin MICs for fluo-

Sonia K. Morgan-Linnell; Lauren Becnel Boyd; David Steffen; Lynn Zechiedrich

2009-01-01

397

Genetic Background of Escherichia coli and Extended spectrum ? ?-Lactamase Type  

Microsoft Academic Search

To assess the implication of the genetic background of Escherichia coli strains in the emergence of extended- spectrum ?-lactamases (ESBL), 55 TEM-, 52 CTX-M-, and 22 SHV-type ESBL-producing clinical isolates involved in various extraintestinal infections or colonization were stud- ied in terms of phylogenetic group, virulence factor (VF) content (pap, sfa\\/foc, hly, and aer genes), and fluoro- quinolone resistance. A

Catherine Branger; Oana Zamfir; Sabine Geoffroy; Genevičve Laurans; Guillaume Arlet; Hoang Vu Thien; Stéphanie Gouriou; Bertrand Picard; Erick Denamur

398

Directed Mutation in Escherichia Coli : Theory and Mechanisms  

Microsoft Academic Search

\\u000a For a haploid unicellular organism, such as Escherichia coli, that reproduces asexually by binary fission, the concept of “self”, or more appropriately, “individual”, may be indistinguishable\\u000a from the concept of organism. Controversy has arisen in the past about whether and how such creatures maintain themselves\\u000a as a species since every new mutant that appears could, theoretically, give rise to a

Patricia L. Foster

399

Escherichia coli and Salmonella 2000: the view from here.  

PubMed

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

Schaechter, M

2001-03-01

400

Characterization of intestinal cnf1 + Escherichia coli from weaned pigs  

Microsoft Academic Search

Escherichia coli isolated from 204 cases of porcine postweaning diarrhoea were tested by PCR for the genes of cytotoxic necrotic factors (CNF) and of cytolethal dystending toxin (CDT). selected strains were also examined by PCR for the presence of papC-, sfa-, f17-, f18- , and afa -specific sequences encoding P, S, F17, F18 fimbriae and afimbrial adhesins. A 5.9% (12\\/204)

István Tóth; Eric Oswald; Jacques G. Mainil; Mohamed Awad-Masalmeh; Béla Nagy

2000-01-01

401

Bacteroides fragilis concealed in an infant with Escherichia coli meningitis.  

PubMed

Anaerobic meningitis in infants is rare, therefore a high index of clinical suspicion is essential as routine methods for processing cerebrospinal fluid (CSF) do not detect anaerobes and specific antimicrobial therapy is required. We present an infant with Escherichia coli meningitis where treatment-resistance developed in association with culture negative purulent CSF. These features should have alerted us to the presence of anaerobes, prompting a search for the causes of polymicrobial meningitis in infants. PMID:24118618

Ganeshalingham, Anusha; Buckley, David; Shaw, Ian; Freeman, Joshua T; Wilson, Francessa; Best, Emma

2014-01-01

402

Energetics of calcium efflux from cells of Escherichia coli.  

PubMed Central

Intact cells of a H+-translocating ATPase-deficient strain of Escherichia coli were starved of endogenous energy reserves and passively loaded with 45CaCl2. Energy-dependent efflux of calcium was observed upon addition of glucose or respiratory substrates. Addition of cyanide or uncouplers prevented efflux. It is concluded that calcium efflux in intact cells is coupled to the proton motive force via secondary calcium-proton exchange.

Tsujibo, H; Rosen, B P

1983-01-01

403

Effects of Chromosome Underreplication on Cell Division in Escherichia coli  

Microsoft Academic Search

The key processes of the bacterial cell cycle are controlled and coordinated to match cellular mass growth. We have studied the coordination between replication and cell division by using a temperature-controlled Escherichia coli intR1 strain. In this strain, the initiation time for chromosome replication can be displaced to later (underreplication) or earlier (overreplication) times in the cell cycle. We used

EMILIA BOTELLO; KURT NORDSTROM

1998-01-01