These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Integrated Genomic Map from Uropathogenic Escherichia coli J96  

Microsoft Academic Search

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

LYLA J. MELKERSON-WATSON; CHRISTOPHER K. RODE; LIXIN ZHANG; BETSY FOXMAN; CRAIG A. BLOCH

2000-01-01

2

Uropathogenic Escherichia coli Flagella Aid in Efficient Urinary Tract Colonization  

Microsoft Academic Search

In the murine model of urinary tract infections (UTI), cystitis by uropathogenic Escherichia coli (UPEC) occurs through an intimate relationship with the bladder superficial umbrella cell entailing cycles of adher- ence, invasion, intracellular bacterial community (IBC) formation, and dispersal (fluxing) from the intracel- lular environment. IBC dispersal is a key step that results in the spread of bacteria over the

Kelly J. Wright; Patrick C. Seed; Scott J. Hultgren

2005-01-01

3

Instability of Pathogenicity Islands in Uropathogenic Escherichia coli 536  

Microsoft Academic Search

The uropathogenic Escherichia coli strain 536 carries at least five genetic elements on its chromosome that meet all criteria characteristic of pathogenicity islands (PAIs). One main feature of these distinct DNA regions is their instability. We applied the so-called island-probing approach and individually labeled all five PAIs of E. coli 536 with the counterselectable marker sacB to evaluate the frequency

Barbara Middendorf; Bianca Hochhut; Kristina Leipold; Ulrich Dobrindt; Gabriele Blum-Oehler; Jorg Hacker

2004-01-01

4

Measuring the forces involved in polyvalent adhesion of uropathogenic Escherichia coli to  

E-print Network

Measuring the forces involved in polyvalent adhesion of uropathogenic Escherichia coli to mannose from the interaction of uropathogenic Escherichia coli to molecularly well defined models of cellular, Escherichia coli [the primary causative agent of urinary tract infections (3, 4)] use the FimH adhesin located

Prentiss, Mara

5

Genomic Islands of Uropathogenic Escherichia coli Contribute to Virulence  

Microsoft Academic Search

Uropathogenic Escherichia coli (UPEC) strain CFT073 contains 13 large genomic islands ranging in size from 32 kb to 123 kb. Eleven of these genomic islands were individually deleted from the genome, and nine isogenic mutants were tested for their ability to colonize the CBA\\/J mouse model of ascending urinary tract infection. Three genomic island mutants (PAI-aspV, PAI-metV, and PAI-asnT) were

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

2009-01-01

6

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

7

Biofilm and fluoroquinolone resistance of canine Escherichia coli uropathogenic isolates  

PubMed Central

Background Escherichia coli is the most common uropathogen involved in urinary tract infection (UTI). Virulence of strains may differ, and may be enhanced by antimicrobial resistance and biofilm formation, resulting in increased morbidity and recurrent infections. The aim of this study was to evaluate the in vitro biofilm forming capacity of E. coli isolates from dogs with UTI, by using fluorescent in situ hybridization, and its association with virulence genes and antimicrobial resistance. Findings The proportion of biofilm-producing isolates significantly increased with the length of incubation time (P??0.05), but was significantly associated with afa, aer and the ?-lactamase genes (P?coli isolates from dogs with UTI. Biofilm formation may contribute to UTI treatment failure in dogs, through the development of bacterial reservoirs inside bladder cells, allowing them to overcome host immune defenses and to establish recurrent infections. PMID:25099929

2014-01-01

8

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. PMID:22590682

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

2012-01-01

9

Regulation of fim genes in uropathogenic Escherichia coli  

PubMed Central

Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections in women, causing significant morbidity and mortality in this population. Adherence to host epithelial cells is a pivotal step in the pathogenesis of UPEC. One of the most important virulence factors involved in mediating this attachment is the type 1 pilus (type 1 fimbria) encoded by a set of fim genes arranged in an operon. The expression of type 1 pili is controlled by a phenomenon known as phase variation, which reversibly switches between the expression of type 1 pili (Phase-ON) and loss of expression (Phase-OFF). Phase-ON cells have the promoter for the fimA structural gene on an invertible DNA element called fimS, which lines up to allow transcription, whereas transcription of the structural gene is silenced in Phase-OFF cells. The orientation of the fimS invertible element is controlled by two site-specific recombinases, FimB and FimE. Environmental conditions cause transcriptional and post-transcriptional changes in UPEC cells that affect the level of regulatory proteins, which in turn play vital roles in modulating this phase switching ability. The role of fim gene regulation in UPEC pathogenesis will be discussed. PMID:23638406

Schwan, William R

2013-01-01

10

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

E-print Network

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...

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

2014-07-01

11

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

E-print Network

Lifting the Mask: Identification of New Small Molecule Inhibitors of Uropathogenic Escherichia coli Group 2 Capsule Biogenesis Carlos C. Goller1., Mehreen Arshad1., James W. Noah2, Subramaniam Ananthan2, Carrie W. Evans2, N. Miranda Nebane2, Lynn... Carolina, United States of America Abstract 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...

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

2014-07-01

12

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

13

Photoluminescent gold nanoclusters as sensing probes for uropathogenic Escherichia coli.  

PubMed

Glycan-bound nanoprobes have been demonstrated as suitable sensing probes for bacteria containing glycan binding sites. In this study, we demonstrated a facile approach for generating glycan-bound gold nanoclusters (AuNCs). The generated AuNCs were used as sensing probes for corresponding target bacteria. Mannose-capped AuNCs (AuNCs@Mann) were generated and used as the model sensors for target bacteria. A one-step synthesis approach was employed to generate AuNCs@Mann. In this approach, an aqueous solution of tetrachloroauric acid and mannoside that functionized with a thiol group (Mann-SH) was stirred at room temperature for 48 h. The mannoside functions as reducing and capping agent. The size of the generated AuNCs@Mann is 1.95±0.27 nm, whereas the AuNCs with red photoluminescence have a maximum emission wavelength of ~630 nm (?excitation = 375 nm). The synthesis of the AuNCs@Mann was accelerated by microwave heating, which enabled the synthesis of the AuNCs@Mann to complete within 1 h. The generated AuNCs@Mann are capable of selectively binding to the urinary tract infection isolate Escherichia coli J96 containing the mannose binding protein FimH expressed on the type 1 pili. On the basis of the naked eye observation, the limit of detection of the sensing approach is as low as ~2×10(6) cells/mL. PMID:23554874

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

2013-01-01

14

Photoluminescent Gold Nanoclusters as Sensing Probes for Uropathogenic Escherichia coli  

PubMed Central

Glycan-bound nanoprobes have been demonstrated as suitable sensing probes for bacteria containing glycan binding sites. In this study, we demonstrated a facile approach for generating glycan-bound gold nanoclusters (AuNCs). The generated AuNCs were used as sensing probes for corresponding target bacteria. Mannose-capped AuNCs (AuNCs@Mann) were generated and used as the model sensors for target bacteria. A one-step synthesis approach was employed to generate AuNCs@Mann. In this approach, an aqueous solution of tetrachloroauric acid and mannoside that functionized with a thiol group (Mann-SH) was stirred at room temperature for 48 h. The mannoside functions as reducing and capping agent. The size of the generated AuNCs@Mann is 1.95±0.27 nm, whereas the AuNCs with red photoluminescence have a maximum emission wavelength of ?630 nm (?excitation?=?375 nm). The synthesis of the AuNCs@Mann was accelerated by microwave heating, which enabled the synthesis of the AuNCs@Mann to complete within 1 h. The generated AuNCs@Mann are capable of selectively binding to the urinary tract infection isolate Escherichia coli J96 containing the mannose binding protein FimH expressed on the type 1 pili. On the basis of the naked eye observation, the limit of detection of the sensing approach is as low as ?2×106 cells/mL. PMID:23554874

Lai, Hong-Zheng; Peng, Hwei-Ling; Mong, Kwok Kong Tony; Chen, Yu-Chie

2013-01-01

15

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

Microsoft Academic Search

Type 1 fimbriae are a crucial factor for the virulence of uropathogenic Escherichia coli during the first steps of infection by mediating adhesion to epithelial cells. They are also required for the consequent colonization of the tissues and for invasion of the uroepithelium. Here, we studied the role of the specialized signal transduction system CRP-cAMP in the regulation of type

Claudia M. Müller; Anna Åberg; Jurate Straseviçiene; Levente Em?dy; Bernt Eric Uhlin; Carlos Balsalobre

2009-01-01

16

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. PMID:23252494

Wiles, Travis J; Mulvey, Matthew A

2013-01-01

17

Feline uropathogenic Escherichia coli from Great Britain and New Zealand have dissimilar virulence factor genotypes  

Microsoft Academic Search

We investigated the prevalence of 30 known virulence factor genes (VFGs) in uropathogenic E. coli (UPEC) from two geographically distinct feline populations, using a PCR-based approach. E. coli isolates were also subjected to macrorestriction analysis to assess their phylogenetic relationships. VFG profiles differed considerably according to the geographic origin of the isolates, enabling discriminant analysis to correctly predict population membership

T. Freitag; R. A. Squires; J. Schmid; J. Elliott

2005-01-01

18

Dissemination and Systemic Colonization of Uropathogenic Escherichia coli in a Murine Model of Bacteremia  

PubMed Central

Infection with uropathogenic Escherichia coli (UPEC), the causative agent of most uncomplicated urinary tract infections, proceeds in an ascending manner and, if left untreated, may result in bacteremia and urosepsis. To examine the fate of UPEC after its entry into the bloodstream, we developed a murine model of sublethal bacteremia. CBA/J mice were inoculated intravenously with 1 × 106 CFU of pyelonephritis strain E. coli CFT073 carrying a bioluminescent reporter. Biophotonic imaging, used to monitor the infection over 48 h, demonstrated that the bacteria disseminated systemically and appeared to localize at discrete sites. UPEC was recovered from the spleen, liver, kidneys, lungs, heart, brain, and intestines as early as 20 min postinoculation, peaking at 24 h postinoculation. A nonpathogenic E. coli K-12 strain, however, disseminated at significantly lower levels (P < 0.01) and was cleared from the liver and cecum by 24 h postinoculation. Isogenic mutants lacking type 1 fimbriae, P fimbriae, capsule, TonB, the heme receptors Hma and ChuA, or particularly the sialic acid catabolism enzyme NanA were significantly outcompeted by wild-type CFT073 during bacteremia (P < 0.05), while flagellin and hemolysin mutants were not. PMID:21116344

Smith, Sara N.; Hagan, Erin C.; Lane, M. Chelsea; Mobley, Harry L. T.

2010-01-01

19

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

20

Colicin E2 Expression in Lactobacillus brevis DT24, A Vaginal Probiotic Isolate, against Uropathogenic Escherichia coli  

PubMed Central

Novel therapeutic approaches are needed to combat the urinary tract infection in women. During menstruation elevated protein concentration and increase in oxygen and carbon dioxide concentrations with decrease in vaginal Lactobacilli all together contribute to urinary tract infections. Lactobacillus species are a predominant member of the vaginal microflora and are critical in the prevention of a number of urogenital diseases. In order to increase antimicrobial potential of vaginal Lactobacilli, bacteriocin colicin E2 which has specific activity against uropathogenic Escherichia coli has been overexpressed in vaginal probiotic Lactobacillus brevis DT24. Recombinant Lactobacillus brevis DT24 expressing colicin E2 showed much higher inhibitory activity against uropathogenic Escherichia coli than wild type L. brevis DT24 in vitro. Efficacy of probiotic Lactobacillus brevis DT24 expressing colicin E2 protein is required for further in vivo evaluation. PMID:24649377

Trivedi, Disha

2014-01-01

21

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

22

The Small RNA RyhB Contributes to Siderophore Production and Virulence of Uropathogenic Escherichia coli.  

PubMed

In Escherichia coli, the small regulatory noncoding RNA (sRNA) RyhB and the global ferric uptake regulator (Fur) mediate iron acquisition and storage control. Iron is both essential and potentially toxic for most living organisms, making the precise maintenance of iron homeostasis necessary for survival. While the roles of these regulators in iron homeostasis have been well studied in a nonpathogenic E. coli strain, their impact on the production of virulence-associated factors is still unknown for a pathogenic E. coli strain. We thus investigated the roles of RyhB and Fur in iron homeostasis and virulence of the uropathogenic E. coli (UPEC) strain CFT073. In a murine model of urinary tract infection (UTI), deletion of fur alone did not attenuate virulence, whereas a ?ryhB mutant and a ?fur ?ryhB double mutant showed significantly reduced bladder colonization. The ?fur mutant was more sensitive to oxidative stress and produced more of the siderophores enterobactin, salmochelins, and aerobactin than the wild-type strain. In contrast, while RyhB was not implicated in oxidative stress resistance, the ?ryhB mutant produced lower levels of siderophores. This decrease was correlated with the downregulation of shiA (encoding a transporter of shikimate, a precursor of enterobactin and salmochelin biosynthesis) and iucD (involved in aerobactin biosynthesis) in this mutant grown in minimal medium or in human urine. iucD was also downregulated in bladders infected with the ?ryhB mutant compared to those infected with the wild-type strain. Our results thus demonstrate that the sRNA RyhB is involved in production of iron acquisition systems and colonization of the urinary tract by pathogenic E. coli. PMID:25245805

Porcheron, Gaëlle; Habib, Rima; Houle, Sébastien; Caza, Mélissa; Lépine, François; Daigle, France; Massé, Eric; Dozois, Charles M

2014-12-01

23

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

24

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

PubMed Central

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

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

2014-01-01

25

Uropathogenic Escherichia coli Outer Membrane Antigens Expressed during Urinary Tract Infection?  

PubMed Central

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 immunoproteomics approach to vaccine development that has been used successfully to identify vaccine targets in other pathogenic bacteria. Outer membranes were isolated from pyelonephritis strain E. coli CFT073 cultured under conditions that mimic the urinary tract environment, including iron limitation, osmotic stress, human urine, and exposure to uroepithelial cells. To identify antigens that elicit a humoral response during experimental UTI, outer membrane proteins were separated by two-dimensional gel electrophoresis and probed using pooled antisera from 20 CBA/J mice chronically infected with E. coli CFT073. In total, 23 outer membrane antigens, including a novel iron compound receptor, reacted with the antisera and were identified by mass spectrometry. These antigens also included proteins with known roles in UPEC pathogenesis, such as ChuA, IroN, IreA, Iha, IutA, and FliC. These data demonstrate that an antibody response is directed against these virulence-associated factors during UTI. We also show that the genes encoding ChuA, IroN, hypothetical protein c2482, and IutA are significantly more prevalent (P < 0.01) among UPEC strains than among fecal-commensal E. coli isolates. Thus, we suggest that the conserved outer membrane antigens identified in this study could be rational candidates for a UTI vaccine designed to elicit protective immunity against UPEC infection. PMID:17517861

Hagan, Erin C.; Mobley, Harry L. T.

2007-01-01

26

Uropathogenic Escherichia coli in Iran: Serogroup distributions, virulence factors and antimicrobial resistance properties  

PubMed Central

Background Urinary tract infections (UTIs) are one of the most common bacterial infections with global expansion. These infections are predominantly caused by uropathogenic Escherichia coli (UPEC). Methods Totally, 123 strains of Escherichia coli isolated from UTIs patients, using bacterial culture method were subjected to polymerase chain reactions for detection of various O- serogroups, some urovirulence factors, antibiotic resistance genes and resistance to 13 different antibiotics. Results According to data, the distribution of O1, O2, O6, O7 and O16 serogroups were 2.43%, besides O22, O75 and O83 serogroups were 1.62%. Furthermore, the distribution of O4, O8, O15, O21 and O25 serogroups were 5.69%, 3.25%, 21.13%, 4.06% and 26.01%, respectively. Overall, the fim virulence gene had the highest (86.17%) while the usp virulence gene had the lowest distributions of virulence genes in UPEC strains isolated from UTIs patients. The vat and sen virulence genes were not detected in any UPEC strains. Totally, aadA1 (52.84%), and qnr (46.34%) were the most prevalent antibiotic resistance genes while the distribution of cat1 (15.44%), cmlA (15.44%) and dfrA1 (21.95%) were the least. Resistance to penicillin (100%) and tetracycline (73.98%) had the highest while resistance to nitrofurantoin (5.69%) and trimethoprim (16.26%) had the lowest frequencies. Conclusions This study indicated that the UPEC strains which harbored the high numbers of virulence and antibiotic resistance genes had the high ability to cause diseases that are resistant to most antibiotics. In the current situation, it seems that the administration of penicillin and tetracycline for the treatment of UTIs is vain. PMID:23627669

2013-01-01

27

OmpA of Uropathogenic Escherichia coli Promotes Postinvasion Pathogenesis of Cystitis?  

PubMed Central

Type 1 pilus directs bladder epithelial binding and invasion by uropathogenic Escherichia coli (UPEC) in the initial stage of cystitis, but the bacterial determinants of postinvasion events in the pathogenesis of cystitis are largely undetermined. We show here that the UPEC outer membrane protein A (OmpA), a monomeric, major, integral protein component of the bacterial outer membrane, functions as a critical determinant of intracellular virulence for UPEC, promoting persistent infection within bladder epithelium. Using a murine urinary tract infection (UTI) model, we demonstrate that whereas deletion of the UPEC ompA gene did not disrupt initial epithelial binding and invasion by UPEC, it did preclude completion of the intracellular bacterial community (IBC) pathway, accompanied by diminishing bacterial loads in the bladder. This defect in epithelial persistence of the ompA mutant was enhanced in competitive infections with wild-type UPEC. Microscopic examinations revealed that the ompA mutant formed significantly fewer IBCs, and those that were initiated were unable to progress past the early stages of maturation. These defects could be corrected by complementation of ompA. In addition, expression of ompA during wild-type UTI was sharply increased at time points correlated with IBC development and the arrival of host immune effector cells. Our findings establish OmpA as a key UPEC virulence factor that functions after epithelial invasion to facilitate IBC maturation and chronic bacterial persistence. PMID:19797074

Nicholson, Tracy F.; Watts, Kristin M.; Hunstad, David A.

2009-01-01

28

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

PubMed Central

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

Mysorekar, Indira U.; Hultgren, Scott J.

2006-01-01

29

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

30

FNR Regulates Expression of Important Virulence Factors Contributing to Pathogenicity of Uropathogenic Escherichia coli.  

PubMed

Uropathogenic Escherichia coli (UPEC) is responsible for the majority of urinary tract infections (UTIs), which are some of the world's most common bacterial infections of humans. Here, we examined the role of FNR (fumarate and nitrate reduction), a well-known global regulator, in the pathogenesis of UPEC infections. We constructed an fnr deletion mutant of UPEC CFT073 and compared it to the wild type for changes in virulence, adherence, invasion, and expression of key virulence factors. Compared to the wild type, the fnr mutant was highly attenuated in the mouse model of human UTI and showed severe defects in adherence to and invasion of bladder and kidney epithelial cells. Our results showed that FNR regulates motility and multiple virulence factors, including expression of type I and P fimbriae, modulation of hemolysin expression, and expression of a novel pathogenicity island involved in ?-ketoglutarate metabolism under anaerobic conditions. Our results demonstrate that FNR is a key global regulator of UPEC virulence and controls expression of important virulence factors that contribute to UPEC pathogenicity. PMID:25245807

Barbieri, Nicolle L; Nicholson, Bryon; Hussein, Ashraf; Cai, Wentong; Wannemuehler, Yvonne M; Dell'Anna, Giuseppe; Logue, Catherine M; Horn, Fabiana; Nolan, Lisa K; Li, Ganwu

2014-12-01

31

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. PMID:2868893

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

1985-01-01

32

Measuring the forces involved in polyvalent adhesion of uropathogenic Escherichia coli to mannose-presenting surfaces  

PubMed Central

Mechanisms of bacterial pathogenesis have become an increasingly important subject as pathogens have become increasingly resistant to current antibiotics. The adhesion of microorganisms to the surface of host tissue is often a first step in pathogenesis and is a plausible target for new antiinfective agents. Examination of bacterial adhesion has been difficult both because it is polyvalent and because bacterial adhesins often recognize more than one type of cell-surface molecule. This paper describes an experimental procedure that measures the forces of adhesion resulting from the interaction of uropathogenic Escherichia coli to molecularly well defined models of cellular surfaces. This procedure uses self-assembled monolayers (SAMs) to model the surface of epithelial cells and optical tweezers to manipulate the bacteria. Optical tweezers orient the bacteria relative to the surface and, thus, limit the number of points of attachment (that is, the valency of attachment). Using this combination, it was possible to quantify the force required to break a single interaction between pilus and mannose groups linked to the SAM. These results demonstrate the deconvolution and characterization of complicated events in microbial adhesion in terms of specific molecular interactions. They also suggest that the combination of optical tweezers and appropriately functionalized SAMs is a uniquely synergistic system with which to study polyvalent adhesion of bacteria to biologically relevant surfaces and with which to screen for inhibitors of this adhesion. PMID:11078520

Liang, Michael N.; Smith, Stephen P.; Metallo, Steven J.; Choi, Insung S.; Prentiss, Mara; Whitesides, George M.

2000-01-01

33

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. PMID:23383333

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

2013-01-01

34

Temperature Control of Fimbriation Circuit Switch in Uropathogenic Escherichia coli: Quantitative Analysis via Automated Model Abstraction  

PubMed Central

Uropathogenic Escherichia coli (UPEC) represent the predominant cause of urinary tract infections (UTIs). A key UPEC molecular virulence mechanism is type 1 fimbriae, whose expression is controlled by the orientation of an invertible chromosomal DNA element—the fim switch. Temperature has been shown to act as a major regulator of fim switching behavior and is overall an important indicator as well as functional feature of many urologic diseases, including UPEC host-pathogen interaction dynamics. Given this panoptic physiological role of temperature during UTI progression and notable empirical challenges to its direct in vivo studies, in silico modeling of corresponding biochemical and biophysical mechanisms essential to UPEC pathogenicity may significantly aid our understanding of the underlying disease processes. However, rigorous computational analysis of biological systems, such as fim switch temperature control circuit, has hereto presented a notoriously demanding problem due to both the substantial complexity of the gene regulatory networks involved as well as their often characteristically discrete and stochastic dynamics. To address these issues, we have developed an approach that enables automated multiscale abstraction of biological system descriptions based on reaction kinetics. Implemented as a computational tool, this method has allowed us to efficiently analyze the modular organization and behavior of the E. coli fimbriation switch circuit at different temperature settings, thus facilitating new insights into this mode of UPEC molecular virulence regulation. In particular, our results suggest that, with respect to its role in shutting down fimbriae expression, the primary function of FimB recombinase may be to effect a controlled down-regulation (rather than increase) of the ON-to-OFF fim switching rate via temperature-dependent suppression of competing dynamics mediated by recombinase FimE. Our computational analysis further implies that this down-regulation mechanism could be particularly significant inside the host environment, thus potentially contributing further understanding toward the development of novel therapeutic approaches to UPEC-caused UTIs. PMID:20361050

Kuwahara, Hiroyuki; Myers, Chris J.; Samoilov, Michael S.

2010-01-01

35

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. PMID:24324225

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

36

Pilicide ec240 Disrupts Virulence Circuits in Uropathogenic Escherichia coli  

PubMed Central

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

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

2014-01-01

37

Role of Histone-Like Proteins H-NS and StpA in Expression of Virulence Determinants of Uropathogenic Escherichia coli  

Microsoft Academic Search

The histone-like protein H-NS is a global regulator in Escherichia coli that has been intensively studied in nonpathogenic strains. However, no comprehensive study on the role of H-NS and its paralogue, StpA, in gene expression in pathogenic E. coli has been carried out so far. Here, we monitored the global effects of H-NS and StpA in a uropathogenic E. coli

Claudia M. Muller; Ulrich Dobrindt; Gabor Nagy; Levente Emody; Bernt Eric Uhlin; Jorg Hacker

2006-01-01

38

Induction of a State of Iron Limitation in Uropathogenic Escherichia coli CFT073 by Cranberry-Derived Proanthocyanidins as Revealed by Microarray Analysis ?  

PubMed Central

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, Andre; Fatisson, Julien; O'May, Che; Asadishad, Bahareh; Schinner, Tim; Tufenkji, Nathalie

2011-01-01

39

Identification of genes subject to positive selection in uropathogenic strains of Escherichia coli: a comparative genomics approach.  

PubMed

Escherichia coli is a model laboratory bacterium, a species that is widely distributed in the environment, as well as a mutualist and pathogen in its human hosts. As such, E. coli represents an attractive organism to study how environment impacts microbial genome structure and function. Uropathogenic E. coli (UPEC) must adapt to life in several microbial communities in the human body, and has a complex life cycle in the bladder when it causes acute or recurrent urinary tract infection (UTI). Several studies designed to identify virulence factors have focused on genes that are uniquely represented in UPEC strains, whereas the role of genes that are common to all E. coli has received much less attention. Here we describe the complete 5,065,741-bp genome sequence of a UPEC strain recovered from a patient with an acute bladder infection and compare it with six other finished E. coli genome sequences. We searched 3,470 ortholog sets for genes that are under positive selection only in UPEC strains. Our maximum likelihood-based analysis yielded 29 genes involved in various aspects of cell surface structure, DNA metabolism, nutrient acquisition, and UTI. These results were validated by resequencing a subset of the 29 genes in a panel of 50 urinary, periurethral, and rectal E. coli isolates from patients with UTI. These studies outline a computational approach that may be broadly applicable for studying strain-specific adaptation and pathogenesis in other bacteria. PMID:16585510

Chen, Swaine L; Hung, Chia-Seui; Xu, Jian; Reigstad, Christopher S; Magrini, Vincent; Sabo, Aniko; Blasiar, Darin; Bieri, Tamberlyn; Meyer, Rekha R; Ozersky, Philip; Armstrong, Jon R; Fulton, Robert S; Latreille, J Phillip; Spieth, John; Hooton, Thomas M; Mardis, Elaine R; Hultgren, Scott J; Gordon, Jeffrey I

2006-04-11

40

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. PMID:22733070

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

41

Bacteriocin synthesis in uropathogenic and commensal Escherichia coli: colicin E1 is a potential virulence factor  

PubMed Central

Background Bacteriocin production is an important characteristic of E. coli strains of human origin. To date, 26 colicin and 9 microcin types have been analyzed on a molecular level allowing molecular detection of the corresponding genes. The production incidence of 29 bacteriocin types and E. coli phylogroups were tested in a set of 361 E. coli strains isolated from human urinary tract infections (UTI) and in 411 control strains isolated from feces of patients without bacterial gut infection. Results Production of 17 and 20 individual bacteriocin types was found in the UTI and control strains, respectively. Microcin H47 encoding determinants were found more often among UTI strains compared to controls (37.9% and 27.0% respectively, p = 0.02) and strains producing microcin H47 belonged predominantly to phylogroup B2 when compared to other bacteriocin producers (67.4% and 36.7%, respectively; p < 0.0001). Producers of 3 or more identified bacteriocin types were more common in the UTI group (20.0% compared to 12.4% in controls, p = 0.03). In the UTI strains, there was a markedly higher number of those producing colicin E1 compared to controls (22.1% to 10.2%, respectively, p = 0.0008). Moreover, colicin E1 production was more common in the UTI bacteriocinogenic strains with multi-producer capabilities. As shown by Southern blotting, pColE1 DNA was not recognized by the ColIa probe and vice versa suggesting that pColE1 was independently associated with pColIa in UTI strains. Conclusion E. coli strains isolated from human urinary tract infections showed increased incidence of microcin H47 and colicin E1 production, respectively. Moreover, colicin E1 itself appears to be a potentially important virulence factor of certain uropathogenic E. coli strains. PMID:21078157

2010-01-01

42

Feline uropathogenic Escherichia coli from Great Britain and New Zealand have dissimilar virulence factor genotypes.  

PubMed

We investigated the prevalence of 30 known virulence factor genes (VFGs) in uropathogenic E. coli (UPEC) from two geographically distinct feline populations, using a PCR-based approach. E. coli isolates were also subjected to macrorestriction analysis to assess their phylogenetic relationships. VFG profiles differed considerably according to the geographic origin of the isolates, enabling discriminant analysis to correctly predict population membership for 15/15 NZ isolates and 18/22 UK isolates. The prevalence of gene markers for P-fimbriae (PapA, PapC, PapEF, and PapG III), colicin V (CvaC), increased serum survival factor (Iss), complement resistance factor (TraT), pathogenicity-associated island (MalX), iron-regulated siderophore receptor (IreA) and haemolysin (HlyD) differed significantly between UK and NZ isolates. Significant phylogenetic differences between the two populations were also identified, but VFG profiles could not be predicted on the basis of phylogenetic relationships. Consequently, a geographically uneven distribution of certain virulence genes, independent of phylogeny, is the likely cause of VFG differences between populations. We cannot rule out that subtle differences in patient disease status may have contributed to the dissimilarity of VFG profiles. PMID:15737476

Freitag, T; Squires, R A; Schmid, J; Elliott, J

2005-03-20

43

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. ...

44

Escherichia coli 83972 inhibits catheter adherence by a broad spectrum of uropathogens  

Microsoft Academic Search

ObjectivesThe presence of a nonpathogenic organism on the surface of a urinary catheter might impede catheter colonization by pathogens and thus prevent urinary tract infection. Previously, we reported that preinoculating urinary catheters with a nonpathogenic strain of Escherichia coli (83972) significantly impeded catheter colonization in vitro by gram-positive bacteria (Enterococcus faecalis). To explore this phenomenon further, we investigated in vitro

Barbara W Trautner; Richard A Hull; Rabih O Darouiche

2003-01-01

45

Hyperbilirubinemia and urinary tract infection: the effect of indirect hyperbilirubinemia on the in vitro growth of uropathogen Escherichia coli in newborn urine.  

PubMed

High serum bilirubin is antioxidant and cytoprotective. We evaluated if urine samples of hyperbilirubinemic newborns impede uropathogenic Escherichia coli growth. Bag-urine samples of hyperbilirubinemic newborns (study group) were cultured at presentation and during remission. Urine sample were obtained only once from healthy newborns (control group). Escherichia coli [2?×?104?colony-forming unit (cfu)/mL] was inoculated into the sterile urine samples and colony counts were determined after 24?h. Bilirubin levels at presentation and remission were also recorded. Escherichia coli colony counts of the control versus study groups and of the presentation versus remission samples in the study group were compared. There were 13 study and 17 control cases. Escherichia coli colony counts were not different in the study group at presentation versus remission (5.4?±?0.7 vs. 5.5?±?0.8 log10, respectively; p?=?0.659). Escherichia coli colony count of the control group (5.2?±?0.6 log10) was also not different from the study group. In conclusion, the urine of hyperbilirubinemic newborns did not affect the growth rate of uropathogenic E. coli. PMID:24059809

Firinci, Fatih; Soylu, Alper; Ozturk, Cengiz; Gulay, Zeynep; Demir, Belde K; Turkmen, Mehmet; Kavukcu, Salih

2014-02-01

46

In vitro adherence of type 1-fimbriated uropathogenic Escherichia coli to human ureteral mucosa.  

PubMed Central

Type 1-fimbriated Escherichia coli isolated from patients with urinary tract infections adhered in vitro to the epithelial cell surface of an excised human ureter. The bacteria also adhered to a mucous coating and to Formalin-fixed human ureteral mucosa. D-Mannose strongly inhibited such adherence. The bacteria in their nonfimbriated phase lacked the ability to adhere. We concluded that type 1 fimbriae play a role, at least in part, in upper urinary tract infections in humans. Images PMID:2568346

Fujita, K; Yamamoto, T; Yokota, T; Kitagawa, R

1989-01-01

47

Effect of cyclosporin on uropathogenic Escherichia coli adherence to human endothelial cells  

Microsoft Academic Search

The effect of cyclosporin A on the adherence of Escherichia coli strains to human umbilical vein endothelial cells was studied. Compared with the controls, bacterial adherence significantly increased following preincubation of the cells with cyclosporin A at 50 mg\\/l and more significantly, to cells preincubated with cyclosporin A at 100–200 mg\\/l. The results showed that cyclosporin A use may be

Andrzej Szkaradkiewicz; Marzena Wal

2001-01-01

48

Occurrence of Antibiotic-Resistant Uropathogenic Escherichia coli Clonal Group A in Wastewater Effluents  

Microsoft Academic Search

Received 21 September 2006\\/Accepted 27 April 2007 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. All 15 CGA isolates (1% of the 1,484 isolates analyzed) exhibited resistance to trimethoprim-sulfamethoxazole

Laura A. Boczek; Eugene W. Rice; Brian Johnston; James R. Johnson

2007-01-01

49

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

PubMed

A fluorometric microplate assay has been developed to determine Escherichia (E.) coli adhesion to uroepithelial cells (UEC). P-fimbriated E. coli were labeled with BacLight Green and preincubated 30 min with human urine or standard. Fluorescent-E. coli were added to UEC in mircoplates at a 400:1 ratio, incubated 1 h, and washed, and the fluorescence intensity was measured. Specific labeling and adherence were confirmed by flow cytometry. A myricetin (1) standard curve (0-30 ?g/mL) was developed; the lower limit of detection was 0.1 ?g/mL, and half-maximal inhibitory concentration was 0.88 ?g/mL (intra- and interassay coefficients of variance were <10% and <15%, respectively). Vaccinium macrocarpon (cranberry) extracts, quercetin (2), and procyanidins B1 (3), B2 (4), and C1 (5) showed similar inhibition. Antiadhesion activity of urine samples from subjects (n = 12) consuming placebo or V. macrocarpon beverage determined using this assay was positively correlated (R(2) = 0.78; p < 0.01) with a radiolabeled-E. coli assay. PMID:24749980

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

2014-05-23

50

Structure-based virtual screening for plant-derived SdiA-selective ligands as potential antivirulent agents against uropathogenic Escherichia coli.  

PubMed

The uropathogenic Escherichia coli pathogenecity is affected by quorum sensing transcriptional regulator SdiA. In this study, in vitro characterization of the active principles that could potentially antagonize with SdiA from the Melia dubia bark extracts has been described. After in vitro assays carried out to evaluate the inhibitory activities against the uropathogenic E. coli, the ethanolic extract (30 mg/ml) which showed the strongest suppression of haemolysis, swarming motility, hydrophobicity and biofilm formation, was subjected to GC-MS analysis and an array of 40 unrelated compounds was identified. Docking studies was conducted to screen for plant-based SdiA inhibitors. Five hits were assessed for their binding profiles and 7-(1-bromoethyl)-3, 3-dimethyl-bicyclo [4.1.0]heptan-2-one showed 66.95% binding ability with respect to C(8)HSL. PMID:22209416

Ravichandiran, Vinothkannan; Shanmugam, Karthi; Anupama, K; Thomas, Sabu; Princy, Adline

2012-02-01

51

Aberrant Community Architecture and Attenuated Persistence of Uropathogenic Escherichia coli in the Absence of Individual IHF Subunits  

PubMed Central

Uropathogenic Escherichia coli (UPEC) utilizes a complex community-based developmental pathway for growth within superficial epithelial cells of the bladder during cystitis. Extracellular DNA (eDNA) is a common matrix component of organized bacterial communities. Integration host factor (IHF) is a heterodimeric protein that binds to double-stranded DNA and produces a hairpin bend. IHF-dependent DNA architectural changes act both intrabacterially and extrabacterially to regulate gene expression and community stability, respectively. We demonstrate that both IHF subunits are required for efficient colonization of the bladder, but are dispensable for early colonization of the kidney. The community architecture of the intracellular bacterial communities (IBCs) is quantitatively different in the absence of either IhfA or IhfB in the murine model for human urinary tract infection (UTI). Restoration of Type 1 pili by ectopic production does not restore colonization in the absence of IhfA, but partially compensates in the absence of IhfB. Furthermore, we describe a binding site for IHF that is upstream of the operon that encodes for the P-pilus. Taken together, these data suggest that both IHF and its constituent subunits (independent of the heterodimer), are able to participate in multiple aspects of the UPEC pathogenic lifestyle, and may have utility as a target for treatment of bacterial cystitis. PMID:23133584

Justice, Sheryl S.; Li, Birong; Downey, Jennifer S.; Dabdoub, Shareef M.; Brockson, M. Elizabeth; Probst, G. Duane; Ray, William C.; Goodman, Steven D.

2012-01-01

52

Immune Modulation by Group B Streptococcus Influences Host Susceptibility to Urinary Tract Infection by Uropathogenic Escherichia coli  

PubMed Central

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.

2012-01-01

53

Flagellin/TLR5 signalling activates renal collecting duct cells and facilitates invasion and cellular translocation of uropathogenic Escherichia coli.  

PubMed

Uropathogenic Escherichia coli (UPEC) colonizing kidneys is the main cause of acute pyelonephritis. TLR5 that senses flagellin was shown to be highly expressed in the bladder and to participate in host defence against flagellated UPEC, although its role in kidneys still remains elusive. Here we show that TLR5 is expressed in renal medullary collecting duct (MCD) cells, which represent a preferential site of UPEC adhesion. Flagellin, like lipopolysaccharide, stimulated the production of the chemoattractant chemokines CXCL1 and CXCL2, and subsequent migration capacity of neutrophils in cultured wild-type (WT) and Tlr4(-/-) MCDs, but not in Tlr5(-/-) MCDs. UPEC can translocate across intact MCD layers without altering tight junctions. Strikingly, the invasion capacity and transcellular translocation of the UPEC strain HT7 were significantly lower in Tlr5(-/-) than in WT MCDs. The non-motile HT7?fliC mutant lacking flagellin also exhibited much lower translocation capacities than the HT7 isolates. Finally, Tlr5(-/-) kidneys exhibited less infiltrating neutrophils than WT kidneys one day after the transurethral inoculation of HT7, and greater delayed renal bacterial loads in the day 4 post-infected Tlr5(-/-) kidneys. Overall, these findings indicate that the epithelial TLR5 participates to renal antibacterial defence, but paradoxically favours the translocation of UPEC across intact MCD cell layers. PMID:24779433

Bens, Marcelle; Vimont, Sophie; Ben Mkaddem, Sanae; Chassin, Cécilia; Goujon, Jean-Michel; Balloy, Viviane; Chignard, Michel; Werts, Catherine; Vandewalle, Alain

2014-10-01

54

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. PMID:21911462

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

2011-01-01

55

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. PMID:23667238

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

2013-01-01

56

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

PubMed Central

The structurally related pap and prs operons of the uropathogenic Escherichia coli isolate J96 encode a P and an F adhesin that mediate bacterial attachment to the human P blood group antigen and the Forssman antigen, respectively. Using probes prepared from different segments of the pap operon, Southern blot hybridizations were performed to characterize pap-related sequences of 30 E. coli clinical isolates expressing different adhesin phenotypes. Gene clusters encoding P and F adhesins displayed no restriction site polymorphism in sequences homologous to the papH, papC, and papD genes that encode proteins essential to the transport and polymerization of the subunits of the P-pilus adhesin. In contrast, pap-related genetic elements associated with a null phenotype either lacked homology to the papH, papC, and papD genes or displayed a restriction site polymorphism in this region. Sequences within and surrounding the J96 papG and prsG adhesin genes that determine the binding specificities to the P and F antigens, respectively, were not conserved. However, gene clusters encoding different binding specificities could not be distinguished based on such restriction site polymorphisms. The majority of clinical isolates had more than one copy of pap-related sequences that involved gene clusters similar to the J96 pap operon, as well as genetic elements that were related only to a part of this operon. The implications of this unexpected copy number polymorphism with respect to possible recombination events involving pap-related sequences are discussed. Images PMID:2563255

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

1989-01-01

57

Molecular analysis and epidemiology of the Dr hemagglutinin of uropathogenic Escherichia coli.  

PubMed Central

The genetic organization and epidemiology of Dr hemagglutinin was studied. Plasmids derived from pBJN406 and carrying transposon inserts were analyzed for their abilities to confer the mannose-resistant hemagglutination phenotype and expression of plasmid-encoded proteins. The 6.6-kilobase DNA fragment expressed five polypeptides with molecular masses of 15.5, 5, 18, 90, and 32 kilodaltons encoded by the draA, draB, draC, draD, and draE genes, respectively. Four genes, draA, draC, draD, and draE, were required for full mannose-resistant hemagglutination expression. Mutation in the draA gene, previously identified as encoding fimbrillin, resulted in loss of the adherence phenotype. We screened 658 strains isolated from patients with urinary tract infections (UTI) or from fecal samples for the presence of DNA sequences homologous to the draD gene. A significantly higher frequency of draD-related sequences was found among Escherichia coli strains from patients with cystitis than among strains from patients with other clinical forms of UTI. Association of draD-related sequences with O75 and other serotypes was observed. A possible role of Dr hemagglutinin as a virulence factor in lower UTI is discussed. Images PMID:2643568

Nowicki, B; Svanborg-Eden, C; Hull, R; Hull, S

1989-01-01

58

Bacterial Lysis Liberates the Neutrophil Migration Suppressor YbcL from the Periplasm of Uropathogenic Escherichia coli.  

PubMed

Uropathogenic Escherichia coli (UPEC) modulates aspects of the innate immune response during urinary tract infection to facilitate bacterial invasion of the bladder epithelium, a requirement for the propagation of infection. For example, UPEC-encoded YbcL suppresses the traversal of bladder epithelia by neutrophils in both an in vitro model and an in vivo murine cystitis model. The suppressive activity of YbcL requires liberation from the bacterial periplasm, though the mechanism of release is undefined. Here we present findings on the site of action of YbcL and demonstrate a novel mode of secretion for a UPEC exoprotein. Suppression of neutrophil migration by purified YbcLUTI, encoded by cystitis isolate UTI89, required the presence of a uroepithelial layer; YbcLUTI did not inhibit neutrophil chemotaxis directly. YbcLUTI was released to a greater extent during UPEC infection of uroepithelial cells than during that of neutrophils. Release of YbcLUTI was maximal when UPEC and bladder epithelial cells were in close proximity. Established modes of secretion, including outer membrane vesicles, the type II secretion system, and the type IV pilus, were dispensable for YbcLUTI release from UPEC. Instead, YbcLUTI was liberated during bacterial death, which was augmented upon exposure to bladder epithelial cells, as confirmed by detection of bacterial cytoplasmic proteins and DNA in the supernatant and enumeration of bacteria with compromised membranes. As YbcLUTI acts on the uroepithelium to attenuate neutrophil migration, this mode of release may represent a type of altruistic cooperation within a UPEC population during colonization of the urinary tract. PMID:25183735

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

2014-12-01

59

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

60

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. PMID:24983234

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

61

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. PMID:23090961

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

2013-01-01

62

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

PubMed

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 muM ZnCl(2)). In contrast, the E. coli K-12 DeltaznuB cell line grew well on minimal medium that was not supplemented with Zn(II). The DeltaznuB mutant was significantly deficient in the 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. PMID:19765083

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

2009-11-01

63

A FimH Inhibitor Prevents Acute Bladder Infection and Treats Chronic Cystitis Caused by Multidrug-Resistant Uropathogenic Escherichia coli ST131  

PubMed Central

Background.?Escherichia coli O25b:H4-ST131 represents a predominant clone of multidrug-resistant uropathogens currently circulating worldwide in hospitals and the community. Urinary tract infections (UTIs) caused by E. coli ST131 are typically associated with limited treatment options and are often recurrent. Methods.?Using established mouse models of acute and chronic UTI, we mapped the pathogenic trajectory of the reference E. coli ST131 UTI isolate, strain EC958. Results.?We demonstrated that E. coli EC958 can invade bladder epithelial cells and form intracellular bacterial communities early during acute UTI. Moreover, E. coli EC958 persisted in the bladder and established chronic UTI. Prophylactic antibiotic administration failed to prevent E. coli EC958–mediated UTI. However, 1 oral dose of a small-molecular-weight compound that inhibits FimH, the type 1 fimbriae adhesin, significantly reduced bacterial colonization of the bladder and prevented acute UTI. Treatment of chronically infected mice with the same FimH inhibitor lowered their bladder bacterial burden by >1000-fold. Conclusions.?In this study, we provide novel insight into the pathogenic mechanisms used by the globally disseminated E. coli ST131 clone during acute and chronic UTI and establish the potential of FimH inhibitors as an alternative treatment against multidrug-resistant E. coli. PMID:23737602

Totsika, Makrina; Kostakioti, Maria; Hannan, Thomas J.; Upton, Mathew; Beatson, Scott A.; Janetka, James W.; Hultgren, Scott J.; Schembri, Mark A.

2013-01-01

64

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

PubMed

Healthcare professionals worldwide have expressed concern over infections by extended-spectrum ß-lactamase (ESBL) and metallo-ß-lactamase (MBL)-producing bacteria. We evaluated the prevalence of ESBL- and MBL-producing Escherichia coli (E. coli) isolated from community-acquired urinary tract infections (UTIs) and their antibiotic-resistance profiles at 3 private laboratories in Tehran, Iran. E. coli isolates were mostly susceptible to meropenem (90.4%) and imipenem (90.0%), followed by amikacin (89.0%) and gentamicin (84.7%). Moreover, we detected that, of the E. coli isolates, 67 (22.3%) were ESBL producers and 21 (7.0%) of E. coli isolates were MBL positive via the imipenem-ethylenediaminetetraacetic acid (EDTA) combined disc test. This report is the first, to our knowledge, on the prevalence of MBL-producing uropathogenic E. coli (UPEC) strains in Iran. The antibiotic resistance of E. coli isolates revealed that 122 (40.7%) were multidrug resistant. The high number of antibiotic-resistant and ß-lactamase-producing UPEC strains necessitates further attention and consideration, particularly MBL-producing strains. PMID:25316659

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

2014-01-01

65

Quinolone-Resistant Uropathogenic Escherichia coli Strains from Phylogenetic Group B2 Have Fewer Virulence Factors than Their Susceptible Counterparts  

PubMed Central

The prevalence of 31 virulence factors was analyzed among nalidixic acid-susceptible and -resistant Escherichia coli strains from phylogenetic group B2. Hemolysin, cytotoxic necrotizing factor 1, and S and F1C fimbriae genes were less prevalent among nalidixic acid-resistant E. coli strains. Quinolone resistance may be associated with a decrease in the presence of some virulence factors. PMID:15956432

Horcajada, Juan P.; Soto, Sara; Gajewski, Abby; Smithson, Alex; Jimenez de Anta, M. Teresa; Mensa, Josep; Vila, Jordi; Johnson, James R.

2005-01-01

66

Uropathogenic Escherichia coli modulates immune responses and its curli fimbriae interact with the antimicrobial peptide LL-37.  

PubMed

Bacterial growth in multicellular communities, or biofilms, offers many potential advantages over single-cell growth, including resistance to antimicrobial factors. Here we describe the interaction between the biofilm-promoting components curli fimbriae and cellulose of uropathogenic E. coli and the endogenous antimicrobial defense in the urinary tract. We also demonstrate the impact of this interplay on the pathogenesis of urinary tract infections. Our results suggest that curli and cellulose exhibit differential and complementary functions. Both of these biofilm components were expressed by a high proportion of clinical E. coli isolates. Curli promoted adherence to epithelial cells and resistance against the human antimicrobial peptide LL-37, but also increased the induction of the proinflammatory cytokine IL-8. Cellulose production, on the other hand, reduced immune induction and hence delayed bacterial elimination from the kidneys. Interestingly, LL-37 inhibited curli formation by preventing the polymerization of the major curli subunit, CsgA. Thus, even relatively low concentrations of LL-37 inhibited curli-mediated biofilm formation in vitro. Taken together, our data demonstrate that biofilm components are involved in the pathogenesis of urinary tract infections by E. coli and can be a target of local immune defense mechanisms. PMID:20661475

Kai-Larsen, Ylva; Lüthje, Petra; Chromek, Milan; Peters, Verena; Wang, Xiaoda; Holm, Asa; Kádas, Lavinia; Hedlund, Kjell-Olof; Johansson, Jan; Chapman, Matthew R; Jacobson, Stefan H; Römling, Ute; Agerberth, Birgitta; Brauner, Annelie

2010-01-01

67

In silico and in vivo studies of truncated forms of flagellin (FliC) of enteroaggregative Escherichia coli fused to FimH from uropathogenic Escherichia coli as a vaccine candidate against urinary tract infections.  

PubMed

The new generation of vaccines against infectious diseases is based on recombinant fusion proteins. Flagellin (FliC) of enteroaggregative Escherichia coli (EAEC) could be considered as a potent adjuvant in designing new vaccines. However, because of its large size, incorporation of this protein with a vaccine antigen might negatively influence recognition of the vaccine epitopes by the immune system. Designing the truncated forms of FliC, capable of inducing innate immune response, enhances the immune responses to the target antigen. We have previously shown that two truncated forms of FliC are able to induce Interleukine-8 production in HT-29 epithelial cell line. In this study we designed recombinant vaccine against urinary tract infections (UTIs) using truncated forms of FliC and type 1 fimbrial FimH adhesin from uropathogenic Escherichia coli (UPEC) and studied their in silico interactions with Toll-like receptor 5 (TLR-5) via docking protocols. The best fusion protein was subjected to cloning and expression. The ability of the recombinant vaccine and the truncated forms in inducing immune responses was investigated. Our results showed that truncated forms are capable of inducing Th1 (forms A and B) and Th2 (form A) responses and fusion vaccine induced strong cellular and humoral immune responses. PMID:24530504

Savar, Nastaran Sadat; Jahanian-Najafabadi, Ali; Mahdavi, Mehdi; Shokrgozar, Mohammad Ali; Jafari, Anis; Bouzari, Saeid

2014-04-10

68

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

69

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. PMID:24235787

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

2013-01-01

70

Functional Analysis of Antigen 43 in Uropathogenic Escherichia coli Reveals a Role in Long-Term Persistence in the Urinary Tract?  

PubMed Central

Escherichia coli is the primary cause of urinary tract infection (UTI) in the developed world. The major factors associated with the 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 subgroup of proteins. The best characterized of these proteins, antigen 43 (Ag43), is a self-recognizing adhesin that is associated with cell aggregation and biofilm formation in E. coli K-12. The sequenced genome of prototype UPEC strain CFT073 contains two variant Ag43-encoding genes located on pathogenicity islands. The biological significance of both of these genes and their role in UPEC pathogenesis have not been investigated previously. Here we performed a detailed molecular characterization analysis of Ag43a (c3655) and Ag43b (c1273) from UPEC CFT073. Expression of Ag43a and Ag43b in a K-12 background revealed that they possess different functional properties. Ag43a produced a strong aggregation phenotype and promoted significant biofilm growth. Deletion mutants and strains constitutively expressing Ag43a and Ag43b were also constructed using CFT073. When these mutants were analyzed in a mouse model of UTI, Ag43a (but not Ag43b) promoted long-term persistence in the urinary bladder. Our findings demonstrate that Ag43a contributes to UPEC disease pathogenesis and reveal that there are pathogenicity-adapted variants of Ag43 with distinct virulence-related functions. PMID:17420234

Ulett, Glen C.; Valle, Jaione; Beloin, Christophe; Sherlock, Orla; Ghigo, Jean-Marc; Schembri, Mark A.

2007-01-01

71

Contribution of cloned virulence factors from uropathogenic Escherichia coli strains to nephropathogenicity in an experimental rat pyelonephritis model.  

PubMed Central

Escherichia coli 536 (O6:K15:H31), which was isolated from a case of urinary tract infection, determines high nephropathogenicity in a rat pyelonephritis system as measured by renal bacterial counts 7 days after infection. The loss of S fimbrial adhesin formation (Sfa-) (mannose-resistant hemagglutination [Mrh-] and fimbria production [Fim-]), serum resistance (Sre-), and hemolysin production (Hly-) in the mutant 536-21 led to a dramatic reduction of bacterial counts from almost 10(5) to only 40 cells per g of kidney. The reintroduction of the cloned S fimbrial adhesin determinant (sfa) increases the virulence of the avirulent mutant strain by a factor of 20; almost the same effect was observed after restoration of serum resistance by integration of an sfa+ recombinant cosmid into the chromosome. Additional reintroduction of the Hly+ phenotype by transformation of two hly determinants increased the virulence of the strains. Hemolysin production determined increased renal elimination of leukocytes and erythrocytes. Thus all three determinants investigated, S fimbriae, serum resistance, and hemolysin, contribute to the multifactorial phenomenon of E. coli nephropathogenicity. Images PMID:2877950

Marre, R; Hacker, J; Henkel, W; Goebel, W

1986-01-01

72

Th1-Th17 Cells Contribute to the Development of Uropathogenic Escherichia coli-Induced Chronic Pelvic Pain  

PubMed Central

The etiology of chronic prostatitis/chronic pelvic pain syndrome in men is unknown but may involve microbes and autoimmune mechanisms. We developed an infection model of chronic pelvic pain in NOD/ShiLtJ (NOD) mice with a clinical Escherichia coli isolate (CP-1) from a patient with chronic pelvic pain. We investigated pain mechanisms in NOD mice and compared it to C57BL/6 (B6) mice, a strain resistant to CP-1-induced pain. Adoptive transfer of CD4+ T cells, but not serum, from CP-1-infected NOD mice was sufficient to induce chronic pelvic pain. CD4+ T cells in CP-1-infected NOD mice expressed IFN-? and IL-17A but not IL-4, consistent with a Th1/Th17 immune signature. Adoptive transfer of ex-vivo expanded IFN-? or IL-17A-expressing cells was sufficient to induce pelvic pain in naïve NOD recipients. Pelvic pain was not abolished in NOD-IFN-?-KO mice but was associated with an enhanced IL-17A immune response to CP1 infection. These findings demonstrate a novel role for Th1 and Th17-mediated adaptive immune mechanisms in chronic pelvic pain. PMID:23577183

Mukherjee, Soumi; Done, Joseph D.; Schaeffer, Anthony J.; Thumbikat, Praveen

2013-01-01

73

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

74

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. PMID:21819223

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

2011-01-01

75

Assessment of Virulence of Uropathogenic Escherichia coli Type 1 Fimbrial Mutants in Which the Invertible Element Is Phase-Locked On or Off  

PubMed Central

Type 1 fimbria is a proven virulence factor of uropathogenic Escherichia coli (UPEC), causing urinary tract infections. Expression of the fimbria is regulated at the transcriptional level by a promoter situated on an invertible element, which can exist in one of two different orientations. The orientation of the invertible element that allows the expression of type 1 fimbriae is defined as “on,” and the opposite orientation, in which no transcription occurs, is defined as “off.” During the course of a urinary tract infection, we have observed that the infecting E. coli population alternates between fimbriated and nonfimbriated states, with the fimbriated on orientation peaking at 24 h. We propose that the ability of the invertible element to switch orientations during infection is itself a virulence trait. To test this hypothesis, nucleotide sequence changes were introduced in the left inverted repeat of the invertible element of UPEC pyelonephritis strain CFT073 that locked the invertible elements permanently in either the on or the off orientation. The virulence of these mutants was assessed in the CBA mouse model of ascending urinary tract infection at 4, 24, 48, and 72 h postinoculation (hpi). We conducted independent challenges, in which bladders of mice were inoculated with either a single mutant or the wild type, and cochallenges, in which a mutant and the wild type were inoculated together to allow direct competition in the urinary tract. In both sets of experimental infections, the locked-off mutant was recovered from the urine, bladder, and kidneys in significantly lower numbers than the wild type at 24 hpi (P ? 0.05), demonstrating its attenuation. Conversely, the locked-on mutant was recovered in higher numbers than the wild type at 24 hpi (P ? 0.05), showing enhanced virulence of this mutant. No significant differences were seen between the mutants and wild type in the urine or the bladder at 48 or 72 hpi. However, the wild type outcompeted the locked-off mutant in the kidneys during the cochallenge experiment at 72 hpi (P = 0.009). Overall, these data suggest that the ability of the invertible element controlling type 1 fimbria expression to phase vary contributes significantly to virulence early (24 hpi) in the course of a urinary tract infection by UPEC and most profoundly influences colonization of the bladder. PMID:12065472

Gunther, Nereus W.; Snyder, Jennifer A.; Lockatell, Virginia; Blomfield, Ian; Johnson, David E.; Mobley, Harry L. T.

2002-01-01

76

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. PMID:25036370

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

2014-01-01

77

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

78

Pyelonephritogenic Diffusely Adhering Escherichia coli EC7372 Harboring Dr-II Adhesin Carries Classical Uropathogenic Virulence Genes and Promotes Cell Lysis and Apoptosis in Polarized  

Microsoft Academic Search

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

Epithelial Caco; JULIE GUIGNOT; JACQUELINE BREARD; MARIE-FRANCOISE BERNET-CAMARD; ISABELLE PEIFFER; BOGDAN J. NOWICKI; ALAIN L. SERVIN; ANNE-BEATRICE BLANC-POTARD

2000-01-01

79

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. PMID:11083827

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

2000-01-01

80

Escherichia coli (E. coli)  

MedlinePLUS

... so you might hear about E. coli being found in drinking water, which are not themselves harmful, but indicate the ... Infections start when you swallow STEC—in other words, when you get tiny ... consumption of water that has not been disinfected, contact with cattle, ...

81

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. PMID:23357383

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

2013-01-01

82

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. PMID:18453280

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

2008-01-01

83

Comparison of Escherichia coli isolates implicated in human urinary tract infection and avian colibacillosis  

Microsoft Academic Search

Since avian pathogenic Escherichia coli (APEC) and human uropathogenic E. coli (UPEC) may encounter similar challenges when establishing infection in extraintestinal locations, they may share a similar content of virulence genes and capacity to cause disease. In the present study, 524 APEC and 200 UPEC isolates were compared by their content of virulence genes, phylogenetic group, and other traits. The

Kylie E. Rodriguez-Siek; Catherine W. Giddings; Curt Doetkott; Timothy J. Johnson; Mohamed K. Fakhr; Lisa K. Nolan

2005-01-01

84

Article de synthse Escherichia coli  

E-print Network

Article de synthèse Escherichia coli entéropathogènes du lapin D Licois INRA, Station de pathologie diarrhée, chez l'homme ou l'animal. Escherichia coli/ entéropathogène / entérohémorragique / lapin Summary ― Enteropathogenic Escherichia coli from the rabbit. Intestinal pathology is the main cause

Paris-Sud XI, Université de

85

Escherichia coli diarrhoea*  

PubMed Central

In recent years it has become clear that three types of Escherichia coli—enterotoxigenic, enteropathogenic, and enteroinvasive—play important roles in the etiology of acute diarrhoea. This report reviews the available knowledge on the epidemiology, clinical features, and pathophysiology of acute diarrhoea caused by these three types of E. coli, summarizes information on their laboratory diagnosis, and outlines priorities for further research. Particular attention is paid to important aspects of the relationship between enterotoxigenic E. coli diarrhoea in young animals and in man, and to recent advances in the development of E. coli vaccines for use in animals and their potential relevance to the development of an E. coli vaccine for use in man. PMID:6991145

1980-01-01

86

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

87

Screening of SdiA inhibitors from Melia dubia seeds extracts towards the hold back of uropathogenic E.coli quorum sensing-regulated factors.  

PubMed

Plants have always been a supreme source of drugs and India is endowed with a wide variety of them with high medicinal values. The Quorum Sensing (QS) quenching efficiency of various solvent extracts of Melia dubia seeds was investigated against uropathogenic Escherichia coli (UPEC) to screen the competitive inhibitor of SdiA, a transcriptional activator of quorum sensing in E. coli. In this study, potentiality of five different extracts of Melia dubia seeds for quorum sensing inhibitory activity was investigated against uropathogenic Escherichia coli (UPEC). Assays such as cell density, swarming motility, protein, protease, hemolysis, hemagglutination, hydrophobicity and biofilm inhibition were performed. Biofilm, hemolysis and swarming motility were found to be inhibited by 92.1%, 20.9 % and 48.52% respectively, when the medium was supplemented with 30 mg/ml of the ethanolic extract. GC-MS spectrum of the ethanolic extract showed an array of 27 structurally unlinked compounds with natural ligand C8HSL. The docking against QS transcriptional regulator SdiA was predicted by in silico studies and the ligand C6 showed significant activity with -10.8 GScore. In vitro and in silico docking analysis showed fairly a good correlation, suggesting that the ethanolic extract showed potency to attenuate quorum sensing of uropathogenic E. coli. Further studies by in vitro and in vivo strategies are necessary to foresee the quorum quenching effect of the ligands. PMID:23210902

Ravichandiran, Vinothkannan; Shanmugam, Karthi; Solomon, Adline Princy

2013-09-01

88

Serogroups of Escherichia coli from Drinking Water  

Microsoft Academic Search

Fifty seven isolates of thermotolerant E. coli were recovered from 188 drinking water sources, 45 (78.9%) were typable of which 15 (26.3%) were pathogenic serotypes. Pathogenic\\u000a serogroup obtained were 04 (Uropathogenic E. coli, UPEC), 025 (Enterotoxigenic E. coli, ETEC), 086 (Enteropathogenic E. coli, EPEC), 0103 (Shiga-toxin producing E. coli, STEC), 0157 (Shiga-toxin producing E. coli, STEC), 08 (Enterotoxigenic E. coli,

P. W. Ramteke; Suman Tewari

2007-01-01

89

Escherichia coli pathotypes occupy distinct niches in the mouse intestine.  

PubMed

Since the first step of the infection process is colonization of the host, it is important to understand how Escherichia coli pathogens successfully colonize the intestine. We previously showed that enterohemorrhagic O157:H7 strain E. coli EDL933 colonizes a niche in the streptomycin-treated mouse intestine that is distinct from that of human commensal strains, which explains how E. coli EDL933 overcomes colonization resistance imparted by some, but not all, commensal E. coli strains. Here we sought to determine if other E. coli pathogens use a similar strategy. We found that uropathogenic E. coli CFT073 and enteropathogenic E. coli E2348/69 occupy intestinal niches that are distinct from that of E. coli EDL933. In contrast, two enterohemorrhagic strains, E. coli EDL933 and E. coli Sakai, occupy the same niche, suggesting that strategies to prevent colonization by a given pathotype should be effective against other strains of the same pathotype. However, we found that a combination of commensal E. coli strains that can prevent colonization by E. coli EDL933 did not prevent colonization by E. coli CFT073 or E. coli E2348/69. Our results indicate that development of probiotics to target multiple E. coli pathotypes will be problematic, as the factors that govern niche occupation and hence stable colonization vary significantly among strains. PMID:24566621

Meador, Jessica P; Caldwell, Matthew E; Cohen, Paul S; Conway, Tyrrell

2014-05-01

90

Natural Genetic Transformation of Clinical Isolates of Escherichia coli in Urine and Water  

Microsoft Academic Search

Transfer of plasmid-borne antibiotic resistance genes in Escherichia coli wild-type strains is possible by transformation under naturally occurring conditions in oligotrophic, aquatic environments containing phys- iologic concentrations of calcium. In contrast, transformation is suppressed in nitrogen-rich body fluids like urine, a common habitat of uropathogenic strains. Current knowledge indicates that transformation of these E. coli wild-type strains is of no

Markus Woegerbauer; Bernard Jenni; Florian Thalhammer; Wolfgang Graninger; Heinz Burgmann

2002-01-01

91

Review article Avian pathogenic Escherichia coli (APEC)  

E-print Network

Review article Avian pathogenic Escherichia coli (APEC) Maryvonne Dho-Moulina John Morris Inra/Elscvier, Paris. avian / Escherichia coli / virulence / fimbriae / capsule / aerobactin.int-a. li- #12;Résumé-Escherichia coli pathogènes aviaires (APEC). Les Escherichia coli pathogènes aviaires

Paris-Sud XI, Université de

92

Escherichia coli proteomics and bioinformatics  

E-print Network

A lot of things happen to proteins when Escherichia coli cells enter stationary phase, such as protein amount, post-translational modifications, conformation changes, and component of protein complex. Proteomics, which study the whole component...

Niu, Lili

2009-05-15

93

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

PubMed

A collection of 201 Escherichia coli strains isolated from urine of patients in a Tunisian hospital between January 2006 and July 2008 was studied. Microbial identification was done by conventional methods, and antibiotic susceptibility with disk diffusion method was performed according to the Clinical Laboratory and Standards Institute guidelines. Detection of extended-spectrum beta-lactamase (ESBL) was performed by double-disk synergy test (DDST) and identification was done by PCR and sequencing. ESBL-producing isolates were subjected to molecular typing by random amplified polymorphic DNA (RAPD) and ST131 detection by PCR. Four phylogenetic groups (A, B1, B2 and D), 18 virulence genes and CTX-M group were individualized using PCR. Statistical analysis was done by Pearson ?2 test and Mann-Whitney U test. The strains were recovered primarily from urology (28%), maternity (19%) and medicine (16%) wards. Antibiotic resistance rates were ampicilin (72.1%), nalidixic acid (41.8%), ciprofloxacin (38.8%), gentamicin (23.9%) and cefotaxime (17.4%). Thirty-one of cefotaxime-resistant isolates (n?=?35) had a positive DDST and harboured bla CTX-M-15 gene. Twenty of them (64.5%) belonged to the ST131 clone and showed the same RAPD DNA profile. Ciprofloxacin- and cotrimoxazole-susceptible isolates were significantly associated with phylogenetic group B2, whereas isolates that were resistant to these molecules were associated with B1 and D phylogenetic groups, respectively. Virulence genes were significantly more frequent among ciprofloxacin- and cotrimoxazole-susceptible strains than those resistant to these antibiotics. However, CXT-M-15-producing isolates were associated with many virulence genes. Isolates concomitantly susceptible to the three antimicrobials agents (ciprofloxacin, cefotaxime and cotrimoxazole) were significantly associated with group B2 and high virulence score, whereas isolates with resistance patterns especially those including resistance to ciprofloxacin belonged predominantly to B1 phylogroup and haboured few virulence genes. The emergence of virulent and multidrug-resistant E. coli is a concerning development that deserves close attention in our institution. PMID:24258848

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

2014-05-01

94

Role of cloned virulence factors (mannose-resistant haemagglutination, mannose-resistant adhesions) from uropathogenic Escherichia coli strains in the release of inflammatory mediators from neutrophils and mast cells.  

PubMed Central

Genetically cloned E. coli strains expressing cloned virulence factors were studied with regard to their capability to induce inflammatory mediator release from various target cells. Among the strains were E. coli strains with mannose-resistant haemagglutination (MRH+) and mannose-resistant adhesins, e.g. E. coli 536/21 pANN 801/4, E. coli 536/21 pANN 921 and E. coli 536/21 pANN 801-1. In comparison, E. coli 536/21, E. coli 536/21 pGB 30 int and E. coli K12, without and with mannose-sensitive haemagglutination (MSH +/-), and adhesins were studied. The properties of the various strains for human PMN with regard to adherence and phagocytosis, chemiluminescence, 5-lipoxygenase activation of arachidonic acid, leukotriene formation, granular enzyme release and release of histamine from rat mast cells were analysed. It is evident that the various biochemical processes of cell activation are dissociated events. The highest chemiluminescence response is obtained with strains expressing MSH+, P-MRH+ or S-MRH+; the presence of S-adhesins suppressed the response. Highest leukotriene formation is obtained with E. coli 536/21 pANN 801-4, while E. coli with MSH was inactive. The concomitant presence of haemolysin secretion enhanced mediator release significantly. Our data suggest a potent role for mannose-resistant haemagglutination (MRH), adhesins and haemolysin as virulence factors in inducing the release of inflammatory mediators. PMID:2569441

Konig, W; Konig, B; Scheffer, J; Hacker, J; Goebel, W

1989-01-01

95

Antibiotic Resistance in Uropathogenic E. Coli Strains Isolated from Non-Hospitalized Patients in Pakistan  

PubMed Central

Purpose: To study multidrug-resistance in Uropathogenic E. Coli (UPEC) isolated from non-hospitalized patients. Materials and Methods: Altogether, 250 bacterial samples were collected from non-hospitalized patients. Their identifications were done on basis of Gram-staining, colony morphology, biochemical testing and PCR. Susceptibility testing was performed by using standard protocols which were recommended by CLSI. Statistical analysis: For comparisons, statistical analysis was performed by using software, Graphpad Prism 5.0 Results: In total, 32% (n = 80) of the isolates were identified as E. Coli strains and their susceptibility patterns for different antibiotics were determined. The data indicated least resistance against tazocin [(TZP) -1.25%], amikacin [(AK) -1.8%], tigecycline [(TGC)- 2.5%] and nitrofurantoin [(F) -3.75%]. For both minocycline (MH) and sulzone (SUL), resistance rate was 5%, for gentamicin (CN), it was 16.25%, while higher resistances were observed against cephalothine [(KF)- 70%], cefotaxime [(CTX) -58.5%], ceftazidime [(CAZ)- 57.5%], cefepime [(FEP) -55%], cefuroxime and cefixime [(CXM) (CFM)- 53.75 %]. Resistance against ciprofloxacin (CIP) was 57.5%, for norfloxacine (NOR), it was 52.5% and incase of sparfloxacin (SPX), it remained 55%. High percentage of the isolates were resistant to cotrimoxazole [(SXT) -86%] and Amoxicillin [AMX-CLA (AMC)- 76%]. No resistance against meropenem (MEM) was observed. Conclusion: Highest level of drug-resistance was observed against trimethoprim-sulfamethoxazole (TMP-SMZ) among clinical isolates of uropathogenic E. Coli collected from non-hospitalized patients. PMID:25386430

Ali, Ihsan; Kumar, Neeraj; Ahmed, Safia

2014-01-01

96

ORIGINAL ARTICLE Competitive interactions in Escherichia coli  

E-print Network

ORIGINAL ARTICLE Competitive interactions in Escherichia coli populations: the role of bacteriocins Escherichia coli strains were generated, each carrying a DNA-degrading bacteriocin (colicins E2 and E7). Using exclusion; Escherichia coli; bacteriocin; structured environment Introduction Without question, bacteriocins

Riley, Margaret

97

Review article Pathogenic diversity of Escherichia coli  

E-print Network

Review article Pathogenic diversity of Escherichia coli and the emergence of 'exotic' islands December 1998) Abstract - Escherichia coli is a highly adaptive bacterial species that is both a member and other bacteria are presented. © Inra/Elsevier, Paris. Escherichia coli / pathogenicity island

Boyer, Edmond

98

Review article Enterotoxigenic Escherichia coli (ETEC)  

E-print Network

Review article Enterotoxigenic Escherichia coli (ETEC) in farm animals Béla Nagy* Péter Zs. Fekete to enterotoxigenic Escherichia coli (ETEC) typically appear as severe watery diarrhoea during the first few daysC novell.vnu-i.hu Résumé - Escherichia coli entérotoxigène (ETEC) chez les animaux de la ferme. L

Paris-Sud XI, Université de

99

Isolation and comparison of Escherichia coli strains from canine and human patients with urinary tract infections.  

PubMed

We analyzed Escherichia coli strains isolated from dogs with urinary tract infections (UTIs) in an attempt to determine if any of these strains were similar to E. coli isolated from humans with UTIs. Using genotypic and phenotypic traits, we identified four canine and six human E. coli UTI isolates that all appeared to be closely related or identical. All isolates shared similar DNA sequences for pyelonephritis-associated pili (pap), alpha-hemolysin (hly), and insertion sequence 5 (IS5), on the basis of Southern blot analysis. Similar outer membrane protein, pilin, and plasmid profiles were obtained for each of the isolates, although minor heterogeneity was observed. All of these isolates expressed a neuraminidase-sensitive binding phenotype in contrast to the majority of human isolates, which are known to express an adhesin that recognizes terminal digalactoside residues. Taken together, these results suggest that similar E. coli uropathogens may be capable of infecting both dogs and humans. To determine if the intestinal tracts of dogs were a reservoir for uropathogenic E. coli, eight paired rectal and urine pap+ E. coli strains were cultured from dogs with UTIs. By using the same genotypic and phenotypic criteria described above as a basis for strain identity, seven of eight urine-rectal pairs showed intrapair identity. However, each urine-rectal pair displayed a unique overall profile and could be distinguished from the other pairs. We conclude that the uropathogen colonizing the bladders of dog can also be the predominant strain colonizing the intestinal tracts. PMID:2901403

Low, D A; Braaten, B A; Ling, G V; Johnson, D L; Ruby, A L

1988-10-01

100

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

PubMed Central

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

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

2013-01-01

101

Identification of Escherichia coli Genes Associated with Urinary Tract Infections  

PubMed Central

Escherichia coli is the most common cause of urinary tract infections (UTIs). E. coli genes epidemiologically associated with UTIs are potentially valuable in developing strategies for treating and/or preventing such infections as well as differentiating uropathogenic E. coli from nonuropathogenic E. coli. To identify E. coli genes associated with UTIs in humans, we combined microarray-based and PCR-based analyses to investigate different E. coli source groups derived from feces of healthy humans and from patients with cystitis, pyelonephritis, or urosepsis. The cjrABC-senB gene cluster, sivH, sisA, sisB, eco274, and fbpB, were identified to be associated with UTIs. Of these, cjrABC-senB, sisA, sisB, and fbpB are known to be involved in urovirulence in the mouse model of ascending UTI. Our results provide evidence to support their roles as urovirulence factors in human UTIs. In addition, the newly identified UTI-associated genes were mainly found in members of phylogenetic groups B2 and/or D. PMID:22075599

Mao, Bin-Hsu; Chang, Yung-Fu; Scaria, Joy; Chang, Chih-Ching; Chou, Li-Wei; Tien, Ni; Wu, Jiunn-Jong; Tseng, Chin-Chung; Wang, Ming-Cheng; Chang, Chao-Chin; Hsu, Yuan-Man

2012-01-01

102

Characterization of urinary Escherichia coli O75 strains.  

PubMed Central

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:H- (18 strains), O75:K95:H- (10 strains), O75:K95:H5 (7 strains), O75:K100:H5 (4 strains), and O75:K-:H55 (5 strains). Generally, biotyping proved to be of no discriminative value. With two exceptions the strains were found to be sensitive to the bactericidal effect of normal human serum. As shown by multilocus enzyme electrophoresis, the whole-cell protein profile (WCPP), and the patterns of the outer membrane proteins and lipopolysaccharides, all but the five O75:H55 strains were genetically closely related to each other and could be classified into one clonal group. The O75:K-:H55 strains proved to be quite different and lacked type 1 fimbriae. All 17 K95 (H-, H5) strains produced hemolysin and P fimbriae. Five of the O75:K5:H- strains were different from the other K5 strains by showing hemagglutinating properties, on the basis of the presence of the OX adhesin. The last two groups are suggested to be uropathogenic and are proposed to represent separate clonal groups or subgroups. PMID:9114391

Nimmich, W; Voigt, W; Seltmann, G

1997-01-01

103

High level indole signalling in Escherichia coli  

E-print Network

1 High level indole signalling in Escherichia coli Hannah Dorne Gaimster Girton College Department of Genetics A dissertation submitted for the degree of Doctor of Philosophy: April 2014 2 Title High level... indole signalling in Escherichia coli Abstract Indole is a small signalling molecule, produced by many species of bacteria, including Escherichia coli. It is made by the enzyme tryptophanase, which converts tryptophan into indole, pyruvate and ammonia...

Gaimster, Hannah Dorne

2014-06-10

104

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

105

Ertapenem Resistance of Escherichia coli  

E-print Network

An ertapenem-resistant Escherichia coli isolate was recovered from peritoneal fluid in a patient who had been treated with imipenem/cilastatin for 10 days. Ertapenem resistance may be explained by a defect in the outer membrane protein and production of extended-spectrum ?-lactamase CTX-M-2. Of all ?-lactam antimicrobial drugs, carbapenems (imipenem, meropenem, and ertapenem) have the most consistent activity against Enterobacteriaceae. Activity is retained against most isolates that produce high-level AmpC ?-lactamases (cephalosporinases) and clavulanic-acid–inhibited extended-spectrum ?-lactamases (ESBL) (1). However, a few carbapenem-resistant enterobacterial isolates have been reported; resistance may be caused by production of carbapenemases (2) or by combined mechanisms of an outer membrane permeability defect and extended-spectrum ?-lactamases or cephalosporinase (3–6). Spread of CTX-M type ESBLs, especially in Escherichia coli, may provide a favorable background for selection of carbapenem resistance. Resistance to the recently introduced ertapenem has not been reported in E. coli associated with a CTX-M-type enzyme. We describe the clinical and microbiologic features associated with an ertapenem-resistant E. coli isolate that had reduced susceptibility to imipenem after in vivo treatment with imipenem/cilastatin and provide a detailed molecular analysis of the antimicrobial drug resistance mechanisms. The Study E. coli CO strain was recovered from a 50-year-old immunocompromised woman who was hospitalized for a combined liver and heart transplant. She had a history of cardiac failure, hepatitis C virus–related liver cirrhosis, and chronic renal insufficiency. After surgery, septic shock developed related to perforation of the colon. The patient received a full dose of imipenem/cilastatin (2 g/day), a reduced dose of vancomycin (400 mg/day), gentamicin

Marie-frédérique Lartigue; Laurent Poirel; Claire Poyart; Hélène Réglier-poupet; Patrice Nordmann

106

The Escherichia coli Peripheral Inner Membrane Proteome*S  

E-print Network

The Escherichia coli Peripheral Inner Membrane Proteome*S Malvina Papanastasiou, Georgia Escherichia coli using a multidisciplinary approach. Initially, we extensively re-an- notated the theoretical- romolecular complexes, and modification and degradation of poplypeptides. Escherichia coli, a model organism

Economou, Tassos

107

GENOMICS AND PROTEOMICS Temporal regulation of enterohemorrhagic Escherichia coli  

E-print Network

GENOMICS AND PROTEOMICS Temporal regulation of enterohemorrhagic Escherichia coli virulence Escherichia coli (EHEC) infections. AI-2 attracted EHEC in agarose plug chemotaxis assays and also increased). However, the introduction of pathogens, such as enterohemorrhagic Escherichia coli (EHEC), into the GI

Wood, Thomas K.

108

21 CFR 866.3255 - Escherichia coli serological reagents.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Escherichia coli serological reagents. 866...Serological Reagents § 866.3255 Escherichia coli serological reagents. (a) Identification. Escherichia coli serological reagents...

2011-04-01

109

ORIGINAL RESEARCH Shigella Strains Are Not Clones of Escherichia coli  

E-print Network

ORIGINAL RESEARCH Shigella Strains Are Not Clones of Escherichia coli but Sister Species Available online 29 December 2012 KEYWORDS Shigella; Escherichia coli; Prokaryote phylogeny and taxonomy; Composition vector; CVTree Abstract Shigella species and Escherichia coli are closely related organisms. Early

Hao, Bailin

110

21 CFR 866.3255 - Escherichia coli serological reagents.  

...2014-04-01 2014-04-01 false Escherichia coli serological reagents. 866...Serological Reagents § 866.3255 Escherichia coli serological reagents. (a) Identification. Escherichia coli serological reagents...

2014-04-01

111

21 CFR 866.3255 - Escherichia coli serological reagents.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Escherichia coli serological reagents. 866...Serological Reagents § 866.3255 Escherichia coli serological reagents. (a) Identification. Escherichia coli serological reagents...

2012-04-01

112

21 CFR 866.3255 - Escherichia coli serological reagents.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Escherichia coli serological reagents. 866...Serological Reagents § 866.3255 Escherichia coli serological reagents. (a) Identification. Escherichia coli serological reagents...

2013-04-01

113

Plasmid replicon typing of commensal and pathogenic Escherichia coli isolates.  

PubMed

Despite the critical role of plasmids in horizontal gene transfer, few studies have characterized plasmid relatedness among different bacterial populations. Recently, a multiplex PCR replicon typing protocol was developed for classification of plasmids occurring in members of the Enterobacteriaceae. Here, a simplified version of this replicon typing procedure which requires only three multiplex panels to identify 18 plasmid replicons is described. This method was used to screen 1,015 Escherichia coli isolates of avian, human, and poultry meat origin for plasmid replicon types. Additionally, the isolates were assessed for their content of several colicin-associated genes. Overall, a high degree of plasmid variability was observed, with 221 different profiles occurring among the 1,015 isolates examined. IncFIB plasmids were the most common type identified, regardless of the source type of E. coli. IncFIB plasmids occurred significantly more often in avian pathogenic E. coli (APEC) and retail poultry E. coli (RPEC) than in uropathogenic E. coli (UPEC) and avian and human fecal commensal E. coli isolates (AFEC and HFEC, respectively). APEC and RPEC were also significantly more likely than UPEC, HFEC, and AFEC to possess the colicin-associated genes cvaC, cbi, and/or cma in conjunction with one or more plasmid replicons. The results suggest that E. coli isolates contaminating retail poultry are notably similar to APEC with regard to plasmid profiles, with both generally containing multiple plasmid replicon types in conjunction with colicin-related genes. In contrast, UPEC and human and avian commensal E. coli isolates generally lack the plasmid replicons and colicin-related genes seen in APEC and RPEC, suggesting limited dissemination of such plasmids among these bacterial populations. PMID:17277222

Johnson, Timothy J; Wannemuehler, Yvonne M; Johnson, Sara J; Logue, Catherine M; White, David G; Doetkott, Curt; Nolan, Lisa K

2007-03-01

114

Plasmid Replicon Typing of Commensal and Pathogenic Escherichia coli Isolates?  

PubMed Central

Despite the critical role of plasmids in horizontal gene transfer, few studies have characterized plasmid relatedness among different bacterial populations. Recently, a multiplex PCR replicon typing protocol was developed for classification of plasmids occurring in members of the Enterobacteriaceae. Here, a simplified version of this replicon typing procedure which requires only three multiplex panels to identify 18 plasmid replicons is described. This method was used to screen 1,015 Escherichia coli isolates of avian, human, and poultry meat origin for plasmid replicon types. Additionally, the isolates were assessed for their content of several colicin-associated genes. Overall, a high degree of plasmid variability was observed, with 221 different profiles occurring among the 1,015 isolates examined. IncFIB plasmids were the most common type identified, regardless of the source type of E. coli. IncFIB plasmids occurred significantly more often in avian pathogenic E. coli (APEC) and retail poultry E. coli (RPEC) than in uropathogenic E. coli (UPEC) and avian and human fecal commensal E. coli isolates (AFEC and HFEC, respectively). APEC and RPEC were also significantly more likely than UPEC, HFEC, and AFEC to possess the colicin-associated genes cvaC, cbi, and/or cma in conjunction with one or more plasmid replicons. The results suggest that E. coli isolates contaminating retail poultry are notably similar to APEC with regard to plasmid profiles, with both generally containing multiple plasmid replicon types in conjunction with colicin-related genes. In contrast, UPEC and human and avian commensal E. coli isolates generally lack the plasmid replicons and colicin-related genes seen in APEC and RPEC, suggesting limited dissemination of such plasmids among these bacterial populations. PMID:17277222

Johnson, Timothy J.; Wannemuehler, Yvonne M.; Johnson, Sara J.; Logue, Catherine M.; White, David G.; Doetkott, Curt; Nolan, Lisa K.

2007-01-01

115

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

116

Interaction of Escherichia coli O55 hybrids with bacteriophage lambda. A new type of host specificity between Escherichia coli O55 and urinary Escherichia coli  

Microsoft Academic Search

Escherichia coli O55 hybrids able to adsorb the lambda phage were obtained by mating anEscherichia coli O55 recipient with anEscherichia coli K12HfrC donor. ? mutants, capable of forming plaques on these hybrids, were not isolated. A new type of host specificity betweenEscherichia coli O55 and urinaryEscherichia coli J was established. For efficient reduction of the phage plating ability more growth

K. ?ejka; J. Hubá?ek

1974-01-01

117

SEROLOGICAL CROSS-REACTIONS BETWEEN ESCHERICHIA COLI 0157 AND OTHER SPECIES OF THE GENUS ESCHERICHIA  

EPA Science Inventory

Escherichia hermannii, a sorbitol-negative species of the genus Escherichia, has been reported to be agglutinated by Escherichia coli 0157 and four sorbitol-negative species of the genus Escherichia: . hermannii (24 isolates), Escherichia fergusonii (12 isolates), Escherichia vul...

118

Improvement of Escherichia coli growth by kaolinite  

Microsoft Academic Search

Knowledge of the impacts of clay minerals on microorganisms is essential to a complete understanding of microbially-mediated processes. Information available in this regard remains scarce. Using Escherichia coli (E. coli) as a model bacterium, we investigated the effect of kaolinite on various growth parameters. This clay mineral significantly affected maximal growth rate and yield of the E. coli-strain (MG 1655)

Elise Courvoisier; Sam Dukan

2009-01-01

119

Immunity to Enterotoxigenic Escherichia coli  

PubMed Central

Enterotoxigenic Escherichia coli strains represent the most frequent etiological agent of travelers diarrhea. Challenge studies with several of these strains were undertaken in volunteers to evaluate the mechanisms of disease-induced immunity. Seventeen students and other community volunteers were given 106 or 108 organisms of E. coli B7A (O148:H28), which produces heat-labile and heat-stable enterotoxins. Ten individuals developed diarrheal illness closely resembling natural travelers diarrhea; of these ten, rises in titer of serum antitoxin and anti-O antibody occurred in eight (80%). Eight of the volunteers who developed diarrhea in the first test agreed to undergo rechallenge 9 weeks later with 108 B7A organisms. Only one of these eight “veterans” developed diarrhea versus seven of twelve controls given the same challenge (P = 0.05). Despite clinical protection, all “veterans” excreted B7A after rechallenge. Four controls who developed diarrhea during the homologous B7A rechallenge test were rechallenged 9 weeks later with 109 organisms of E. coli strain E2528-C1 (O25:H-), which produces only heat-labile enterotoxin and possesses a different O, H, and pili antigen composition than B7A. Three of four “veterans” and two of six controls developed comparable diarrhea. These studies demonstrate that prior disease due to enterotoxigenic E. coli confers homologous immunity against subsequent challenge, and the operative mechanism apparently is not bactericidal and is not mediated by serum anti-O antibodies. Heterologous protection was not conferred where the only common antigen was heat-labile enterotoxin, indicating that serum infection-derived antitoxin to heat-labile enterotoxin also is not protective. PMID:378834

Levine, Myron M.; Nalin, David R.; Hoover, David L.; Bergquist, Erick J.; Hornick, Richard B.; Young, Charles R.

1979-01-01

120

Nonchemotactic Mutants of Escherichia coli  

PubMed Central

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

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

1967-01-01

121

Vinylglycolate resistance in Escherichia coli.  

PubMed Central

Escherichia coli K-12 vinylglycolate-resistant mutants have been isolated and characterized. Two of the mutants, JSH 150 and JSH 151, have been determined to be double mutants, lacking both membrane-bound L-and D-lactate dehydrogenases. The lactate transport system is intact in all strains; both radioactive lactate and vinylglycolate are actively taken up. Likewise, the phosphoenolypyruvate-dependent phosphotransferase system for hexose uptake is active. Vinylglycolate, previously shown to inhibit the phosphoenolpyruvate-dependent phosphotransferase system, has very little effect in the double mutants. The extent of vinylglycolate inhibition in other mutants seems directly related to the activity of the lactate dehydrogenases. This indicates that vinylglycolate is oxidized to 2-keto-3-butenoate before inactivating the phosphoenolpyruvate-dependent phosphotransferase system. These results were found in whole cells and confirmed in isolated membrane vesicles. PMID:1090585

Shaw, L; Grau, F; Kaback, H R; Hong, J S; Walsh, C

1975-01-01

122

Inhibition of TIR Domain Signaling by TcpC: MyD88Dependent and Independent Effects on Escherichia coli Virulence  

Microsoft Academic Search

Toll-like receptor signaling requires functional Toll\\/interleukin-1 (IL-1) receptor (TIR) domains to activate innate immunity. By producing TIR homologous proteins, microbes inhibit host response induction and improve their own survival. The TIR homologous protein TcpC was recently identified as a virulence factor in uropathogenic Escherichia coli (E. coli), suppressing innate immunity by binding to MyD88. This study examined how the host

Manisha Yadav; Jingyao Zhang; Hans Fischer; Wen Huang; Nataliya Lutay; Christine Cirl; Josephine Lum; Thomas Miethke; Catharina Svanborg

2010-01-01

123

Curr Top Microbiol Immunol . Author manuscript Escherichia coli biofilms  

E-print Network

; growth & development ; Escherichia coli Infections ; microbiology ; Escherichia coli K12 ; physiologyCurr Top Microbiol Immunol . Author manuscript Page /1 20 Escherichia coli biofilms Christophe of the gastrointestinal tract. Both its frequentEscherichia coli community lifestyle and the availability of a wide array

Paris-Sud XI, Université de

124

Characterization of Urinary Tract Infection-Associated Shiga Toxin-Producing Escherichia coli.  

PubMed

Enterohemorrhagic Escherichia coli (EHEC), a subgroup of Shiga toxin (Stx)-producing E. coli (STEC), is a leading cause of diarrhea and hemolytic-uremic syndrome (HUS) in humans. However, urinary tract infections (UTIs) caused by this microorganism but not associated with diarrhea have occasionally been reported. We geno- and phenotypically characterized three EHEC isolates obtained from the urine of hospitalized patients suffering from UTIs. These isolates carried typical EHEC virulence markers and belonged to HUS-associated E. coli (HUSEC) clones, but they lacked virulence markers typical of uropathogenic E. coli. One isolate exhibited a localized adherence (LA)-like pattern on T24 urinary bladder epithelial cells. Since the glycosphingolipids (GSLs) globotriaosylceramide (Gb3Cer) and globotetraosylceramide (Gb4Cer) are well-known receptors for Stx but also for P fimbriae, a major virulence factor of extraintestinal pathogenic E. coli (ExPEC), the expression of Gb3Cer and Gb4Cer by T24 cells and in murine urinary bladder tissue was examined by thin-layer chromatography and mass spectrometry. We provide data indicating that Stxs released by the EHEC isolates bind to Gb3Cer and Gb4Cer isolated from T24 cells, which were susceptible to Stx. All three EHEC isolates expressed stx genes upon growth in urine. Two strains were able to cause UTI in a murine infection model and could not be outcompeted in urine in vitro by typical uropathogenic E. coli isolates. Our results indicate that despite the lack of ExPEC virulence markers, EHEC variants may exhibit in certain suitable hosts, e.g., in hospital patients, a uropathogenic potential. The contribution of EHEC virulence factors to uropathogenesis remains to be further investigated. PMID:25156739

Toval, Francisco; Schiller, Roswitha; Meisen, Iris; Putze, Johannes; Kouzel, Ivan U; Zhang, Wenlan; Karch, Helge; Bielaszewska, Martina; Mormann, Michael; Müthing, Johannes; Dobrindt, Ulrich

2014-11-01

125

LETTERS Escherichia coli Producing CMY-2  

E-print Network

to various antimicrobial drugs are rapidly increasing in Escherichia coli, not only in health care settings but also in the community. The food supply is suspected as a potential source of antimicrobial-resistant E. coli strains, which include cephalosporin-resistant E. coli found in retail meat products and other types of food (1). We reported a high prevalence of cephalosporin-resistant E. coli, most of which produced CMY-2 ?-lactamase, among retail poultry products in

?-lactamase In

126

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

USGS Publications Warehouse

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

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

2001-01-01

127

Chemical Organizations in the Central Sugar Metabolism of Escherichia Coli  

E-print Network

1 Chemical Organizations in the Central Sugar Metabolism of Escherichia Coli Florian Centler, network analysis, stoichiometry, systems biology, sugar metabolism, Escherichia coli 1.1 Introduction in E. coli including gene expression, signal transduction, and enzymatic activities, some organizations

Dittrich, Peter

128

Recombinant collagen production optimization in Escherichia coli  

E-print Network

An Escherichia coli-based collagen-production process was used to investigate several process optimization objectives for use at the industrial scale. The effect of cooling on fermentation growth kinetics was studied, with ...

Whittemore, Brett A

2005-01-01

129

Starvation and outgrowth response in Escherichia coli  

E-print Network

In order to better understand the mechanisms that graphics. enable Escherichia coli to survive periods of starvation and then resume growth upon addition of nutrients, different aspects of starvation and recovery have been studied. To study...

Holland, Jill Diane

2012-06-07

130

Designed Potent Multivalent Chemoattractants for Escherichia coli$  

E-print Network

Designed Potent Multivalent Chemoattractants for Escherichia coli$ Jason E. Gestwicki, Laura E small molecules (i.e., carbohydrates, amino acids) interact with bacterial chemoreceptors. Although bacterial chemotaxis has been the subject of intense investigations, few have explored the influence

Cairo, Christopher W.

131

Galleria mellonella infection model demonstrates high lethality of ST69 and ST127 uropathogenic E. coli.  

PubMed

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 (10(4) 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. PMID:25061819

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

2014-01-01

132

Structure of Escherichia Coli Tryptophanase  

SciTech Connect

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

Ku,S.; Yip, P.; Howell, P.

2006-01-01

133

Escherichia coli survival in waters: Temperature dependence  

EPA Science Inventory

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

134

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

135

Engineering a Reduced Escherichia coli Genome  

Microsoft Academic Search

Our goal is to construct an improved Escherichia coli to serve both as a better model organism and as a more useful technological tool for genome science. We developed techniques for precise genomic surgery and applied them to deleting the largest K-islands of E. coli, identified by comparative genomics as recent horizontal acquisitions to the genome. They are loaded with

Vitaliy Kolisnychenko; Guy Plunkett; Christopher D. Herring; Tamás Fehér; János Pósfai; Frederick R. Blattner; György Pósfai

2002-01-01

136

Transcriptional proofreading in Escherichia coli.  

PubMed Central

A novel transcriptional proofreading mechanism associated with the beta-subunit of wild-type RNA polymerase from Escherichia coli is suggested from the following data. The purified holoenzyme contains an NTPase activity which specifically converts noncognate NTPs to their corresponding NDP in a template-dependent manner during in vitro transcription of synthetic single- and double-stranded templates. In contrast, purified enzyme from an rpoB mutant which shows increased transcriptional error lacked template-dependent NTP hydrolytic activity. The NTP hydrolytic activity of wild-type enzyme was critically dependent on the integrity of the initiation complex, and required continued transcriptional elongation. Transcription and translation of the lacZ gene proceeded 17% faster in the mutant than in its wild-type parent. These results are discussed in terms of a proofreading model in which the rate of transcription is limited by proofreading events that involve recognition and hydrolysis of noncognate NTPs before they can be misincorporated into RNA. Images PMID:2555156

Libby, R T; Nelson, J L; Calvo, J M; Gallant, J A

1989-01-01

137

Original article Effect of bacteriophage DC22 on Escherichia coli  

E-print Network

Original article Effect of bacteriophage DC22 on Escherichia coli O157:H7 in an artificial rumen -- The effect of a bacteriophage, DC22, on the survival of Escherichia coli O157:H7 in an artificial rumen of 105 PFU of DC22/CFU of E. coli O157:H7 (P Escherichia coli O157:H7 persisted in the control

Boyer, Edmond

138

Carbon nutrition of Escherichia coli in the mouse intestine  

E-print Network

Escherichia coli MG1655 genes induced by growth on mucus, conditions designed to mimic nutrient availabilityCarbon nutrition of Escherichia coli in the mouse intestine Dong-Eun Chang*, Darren J. Smalley E. coli pathogens in some individuals and a barrier to infection in others. Escherichia coli

Conway, Tyrrell

139

A draft genome of Escherichia coli sequence type 127 strain 2009-46  

PubMed Central

Background Escherichia coli are a frequent cause of urinary tract infections (UTI) and are thought to have a foodborne origin. E. coli with sequence type 127 (ST127) are emerging pathogens increasingly implicated as a cause of urinary tract infections (UTI) globally. A ST127 isolate (2009-46) resistant to ampicillin and trimethoprim was recovered from the urine of a 56 year old patient with a UTI from a hospital in Sydney, Australia and was characterised here. Results We sequenced the genome of Escherichia coli 2009-46 using the Illumina Nextera XT and MiSeq technologies. Assembly of the sequence data reconstructed a 5.14 Mbp genome in 89 scaffolds with an N50 of 161 kbp. The genome has extensive similarity to other sequenced uropathogenic E. coli genomes, but also has several genes that are potentially related to virulence and pathogenicity that are not present in the reference E. coli strain. Conclusion E. coli 2009-46 is a multiple antibiotic resistant, phylogroup B2 isolate recovered from a patient with a UTI. This is the first description of a drug resistant E. coli ST127 in Australia.

2014-01-01

140

EM2006K-33 revised Identification of forces shaping the commensal Escherichia coli  

E-print Network

1 EM2006K-33 revised Identification of forces shaping the commensal Escherichia coli genetic title: Commensal Escherichia coli ecological structure Key words: Escherichia coli, commensal, animal forces shaping the Escherichia coli intraspecies ecological structure, we have characterized in terms

141

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. PMID:22798032

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

2012-01-01

142

Iron induces bimodal population development by Escherichia coli  

PubMed Central

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 H2O2 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.

2013-01-01

143

Escherichia coli growth under modeled reduced gravity  

Microsoft Academic Search

Bacteria exhibit varying responses to modeled reduced gravity that can be simulated by clino-rotation. WhenEscherichia coli was subjected to different rotation speeds during clino-rotation, significant differences between modeled reduced gravity\\u000a and normal gravity controls were observed only at higher speeds (30–50 rpm). There was no apparent affect of removing samples\\u000a on the results obtained. WhenE. coli was grown in minimal

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

2004-01-01

144

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. PMID:15504278

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

145

Native valve Escherichia coli endocarditis following urosepsis  

PubMed Central

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

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

2013-01-01

146

Secretory Production of Human Leptin in Escherichia coli  

E-print Network

Secretory Production of Human Leptin in Escherichia coli Ki Jun Jeong, Sang Yup Lee Department homeostasis. In this study, human leptin was pro- duced and secreted efficiently in Escherichia coli using peptide; secre- tion; DsbA; Escherichia coli; protein production INTRODUCTION Human leptin, the product

147

Proteomic analysis of thioredoxin-targeted proteins in Escherichia coli  

E-print Network

Proteomic analysis of thioredoxin-targeted proteins in Escherichia coli Jaya K. Kumar, Stanley present a comprehensive analysis of the thioredoxin-linked Escherichia coli proteome by using tandem in a reaction catalyzed by thioredoxin reductase (4). Originally isolated from Escherichia coli in 1964

Richardson, Charles C.

148

Poly(3-hydroxybutyrate) production from xylose by recombinant Escherichia coli  

E-print Network

Poly(3-hydroxybutyrate) production from xylose by recombinant Escherichia coli Sang Yup Lee Abstract Several recombinant Escherichia coli strains harboring the Alcaligenes eutrophus and methods 2.1 Bacterial strains and plasmids Escherichia coli strains used were B (ATCC 11303), B (DSM 499

149

SHORT COMMUNICATION Occurrence of verocytotoxin-producing Escherichia coli  

E-print Network

SHORT COMMUNICATION Occurrence of verocytotoxin-producing Escherichia coli in the faeces of free Verocytotoxin-producing Escherichia coli (VTEC) is an important group of emerging food-borne pathogens of programmes for controlling VTEC at the farm level. Keywords Verocytotoxin-producing Escherichia coli (VTEC

Paris-Sud XI, Université de

150

Miniseries: Illustrating the Machinery of Life Escherichia coli*  

E-print Network

Miniseries: Illustrating the Machinery of Life Escherichia coli* Received for publication, August that support a recent textbook illustration of an Escherichia coli cell. The image magnifies a portion of life.'' This is how I began my 1991 article that presented several illustrations of Escherichia coli [1

Economou, Tassos

151

Light-powering Escherichia coli with proteorhodopsin Jessica M. Walter*  

E-print Network

Light-powering Escherichia coli with proteorhodopsin Jessica M. Walter* , Derek Greenfield respira- tion is inhibited by depleting oxygen or by the respiratory poison azide, Escherichia coli cells cellular pmf and, thus, viability. Proteorhodopsin allows Escherichia coli cells to withstand environmental

Liphardt, Jan

152

Structure and function of Enterotoxigenic Escherichia coli fimbriae from differing assembly pathways  

E-print Network

Pathogenic enterotoxigenic Escherichia coli (ETEC) are the major bacterial cause of diarrhea in young children in developing countries and in travelers, causing significant mortality in children. Adhesive fimbriae are a prime virulence factor for ETEC, initiating colonization of the small intestinal epithelium. Similar to other Gram-negative bacteria, ETEC express one or more diverse fimbriae, some assembled by the chaperone-usher pathway and others by the alternate chaperone pathway. Here we elucidate structural and biophysical aspects and adaptations of each fimbrial type to its respective host niche. CS20 fimbriae are compared to CFA/I fimbriae, which are two ETEC fimbriae assembled via different pathways, and to Pfimbriae from uropathogenic E. coli. Many fimbriae unwind from their native helical filament to an extended linear conformation under force, thereby sustaining adhesion by reducing load at the point of contact between the bacterium and the target cell. CFA/I fimbriae require the least force to un...

Mortezaei, Narges; Shao, Paul P; Shirdel, Mariam; Singh, Bhupender; McVeigh, Annette; Uhlin, Bernt Eric; Savarino, Stephen J; Andersson, Magnus; Bullitt, Esther

2014-01-01

153

Automatic Tracking of Escherichia Coli Bacteria , Shahid Khan2 3  

E-print Network

bacteria (E. coli), which can generally cause several intestinal and extra-intestinal infections such as urinary tract infections, meningitis, and peritoni- tis. Escherichia coli chemotaxis has been the system of Escherichia Coli Bacteria 825 Fig. 1. (Left) A typical view of E. coli bacteria under a phase

Central Florida, University of

154

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

155

Functional proteomics in Escherichia coli  

E-print Network

-state of E. coli corresponding to hundreds of unique gene products. The copurification of proteins when fractionated at varying pHs could suggest the components of higher order complexes. This non-denaturing proteomic approach should provide physiological...

Champion, Matthew Maurice

2006-04-12

156

Serogroups and virulence genotypes of Escherichia coli isolated from patients with sepsis.  

PubMed

Sixty strains of Escherichia coli, isolated by hemoculture, from septicemic Brazilian patients were evaluated to determine their serogroup and invasivity to Vero cells. All 60 patients died within 2 days of hospitalization. Furthermore, the molecular study of the following extraintestinal pathogenic E. coli-associated virulence factor (VF) genes was performed by PCR: i) adhesins: type 1 fimbria (fimH), S fimbria (sfaD/E), P fimbria (papC and papG alleles) and afimbrial adhesin (afaB/C); ii) capsule K1/K5 (kpsMTII); iii) siderophores: aerobactin (iucD), yersiniabactin (fyuA) and salmochelin (iroN); iv) toxins hemolysin (hlyA), necrotizing cytotoxic factor type 1 (cnf1) and secreted autotransporter toxin (sat); v) miscellaneous: brain microvascular endothelial cells invasion (ibeA), serum resistance (traT), colicin V (cvaC) and specific uropathogenic protein (usp). Our results showed that isolates are able to invade Vero cells (96.6%), differing from previous research on uropathogenic E. coli (UPEC). The O serogroups associated with UPEC were prevalent in 60% of strains vs 11.7% of other serogroups. The PCR results showed a conserved virulence subgroup profile and a prevalence above 75% for fimH, fyuA, kpsMTII and iucD, and between 35-65% for papC, papG, sat, iroN, usp and traT. The evasion from the immunological system of the host and also iron uptake are essential for the survival of extraintestinal pathogenic E. coli strains. Interestingly, among our isolates, a low prevalence of VF genes appeared. Therefore, the present study contributes to the identification of a bacterial profile for sepsis-associated E. coli. PMID:19030710

Ananias, M; Yano, T

2008-10-01

157

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. PMID:23019542

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

158

Asymptomatic Bacteriuria Escherichia coli Are Live Biotherapeutics for UTI  

PubMed Central

Urinary tract infections (UTI) account for approximately 8 million clinic visits annually with symptoms that include acute pelvic pain, dysuria, and irritative voiding. Empiric UTI management with antimicrobials is complicated by increasing antimicrobial resistance among uropathogens, but live biotherapeutics products (LBPs), such as asymptomatic bacteriuria (ASB) strains of E. coli, offer the potential to circumvent antimicrobial resistance. Here we evaluated ASB E. coli as LBPs, relative to ciprofloxacin, for efficacy against infection and visceral pain in a murine UTI model. Visceral pain was quantified as tactile allodynia of the pelvic region in response to mechanical stimulation with von Frey filaments. Whereas ciprofloxacin promoted clearance of uropathogenic E. coli (UPEC), it did not reduce pelvic tactile allodynia, a measure of visceral pain. In contrast, ASB E. coli administered intravesically or intravaginally provided comparable reduction of allodynia similar to intravesical lidocaine. Moreover, ASB E. coli were similarly effective against UTI allodynia induced by Proteus mirabilis, Enterococccus faecalis and Klebsiella pneumoniae. Therefore, ASB E. coli have anti-infective activity comparable to the current standard of care yet also provide superior analgesia. These studies suggest that ASB E. coli represent novel LBPs for UTI symptoms. PMID:25405579

Yaggie, Ryan E.; Schaeffer, Anthony J.; Klumpp, David J.

2014-01-01

159

Pathogenesis of Afa/Dr Diffusely Adhering Escherichia coli  

PubMed Central

Over the last few years, dramatic increases in our knowledge about diffusely adhering Escherichia coli (DAEC) pathogenesis have taken place. The typical class of DAEC includes E. coli strains harboring AfaE-I, AfaE-II, AfaE-III, AfaE-V, Dr, Dr-II, F1845, and NFA-I adhesins (Afa/Dr DAEC); these strains (i) have an identical genetic organization and (ii) allow binding to human decay-accelerating factor (DAF) (Afa/DrDAF subclass) or carcinoembryonic antigen (CEA) (Afa/DrCEA subclass). The atypical class of DAEC includes two subclasses of strains; the atypical subclass 1 includes E. coli strains that express AfaE-VII, AfaE-VIII, AAF-I, AAF-II, and AAF-III adhesins, which (i) have an identical genetic organization and (ii) do not bind to human DAF, and the atypical subclass 2 includes E. coli strains that harbor Afa/Dr adhesins or others adhesins promoting diffuse adhesion, together with pathogenicity islands such as the LEE pathogenicity island (DA-EPEC). In this review, the focus is on Afa/Dr DAEC strains that have been found to be associated with urinary tract infections and with enteric infection. The review aims to provide a broad overview and update of the virulence aspects of these intriguing pathogens. Epidemiological studies, diagnostic techniques, characteristic molecular features of Afa/Dr operons, and the respective role of Afa/Dr adhesins and invasins in pathogenesis are described. Following the recognition of membrane-bound receptors, including type IV collagen, DAF, CEACAM1, CEA, and CEACAM6, by Afa/Dr adhesins, activation of signal transduction pathways leads to structural and functional injuries at brush border and junctional domains and to proinflammatory responses in polarized intestinal cells. In addition, uropathogenic Afa/Dr DAEC strains, following recognition of ?1 integrin as a receptor, enter epithelial cells by a zipper-like, raft- and microtubule-dependent mechanism. Finally, the presence of other, unknown virulence factors and the way that an Afa/Dr DAEC strain emerges from the human intestinal microbiota as a “silent pathogen” are discussed. PMID:15831825

Servin, Alain L.

2005-01-01

160

Detection of Escherichia coli O157 and Escherichia coli O157:H7 by the  

E-print Network

This study was conducted to investigate the presence of Escherichia (E.) coli O157 and E. coli O157:H7 and stx1 and stx2 genes on cattle carcasses and in rectal samples collected from Samsun Province of Turkey. A total of 200 samples collected from cattle carcasses and the rectal contents of 100 slaughtered cattle from two commercial abattoirs were tested using the immunomagnetic separation technique and multiplex PCR methods. E. coli O157 and E. coli O157:H7 were detected in 52 of the 200 samples (26%) tested. Of the positive samples, 49 were E. coli O157 and three were E. coli O157:H7. The E. coli O157 strain was isolated from 24 carcasses and 25 rectal samples, while E. coli O157:H7 was isolated from two carcasses and one rectal sample. Of the 49 samples positive for E. coli O157, 32 were from the rectal and carcass samples of the same animal, while two E. coli O157:H7 isolates were obtained from rectal swabs and carcasses of the same animal. The stx1 and stx2 genes were both detected in 35 E. coli O157 isolates and one E. coli O157:H7 isolate, but the stx2 gene was only detected alone in two E. coli O157 isolates. Overall, 16 carcasses tested positive for E. coli O157 and one carcass tested positive for E. coli O157:H7 based on both carcass and rectal samples. Overall, the results of this study indicate that cattle carcasses pose a potential risk to human health due to contamination by E. coli O157 and E. coli O157:H7 in the feces. Keywords: carcass, cattle, E. coli O157, E. coli O157:H7, rectum, stx1, stx2

Gökhan Inat; Belgin Siriken

2010-01-01

161

Large plasmids of avian Escherichia coli isolates.  

PubMed

The plasmid DNA of 30 Escherichia coli isolates from chickens was extracted and examined using techniques designed to isolate large plasmids. This plasmid DNA was examined for the presence of certain known virulence-related genes including cvaC, traT, and some aerobactin-related sequences. Seventeen of the 30 isolates contained from one to four plasmids greater than 50 kb in size. Eleven of these 17 strains possessed plasmids greater than 100 kb in size. Therefore, E. coli isolates of chickens frequently contain large plasmids, and many of these plasmids are likely to contain virulence-related sequences. PMID:8980827

Doetkott, D M; Nolan, L K; Giddings, C W; Berryhill, D L

1996-01-01

162

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. PMID:21895995

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

2012-01-01

163

Prevalence and antibiogram profiling of Escherichia coli pathotypes isolated from the Kat River and the Fort Beaufort abstraction water.  

PubMed

Escherichia coli is a widespread bacterium encompassing a variety of strains, ranging from highly pathogenic strains, causing worldwide outbreaks of severe diseases to avirulent, well characterized safe laboratory strains. This study evaluated the prevalence and antibiogram profiles of E. coli pathotypes isolated from the Kat River and Fort Beaufort abstraction water. A total of 171 out of 278 confirmed E. coli isolates were positive for at least one pathogenic determinant and these included enteropathogenic E. coli (6%), enterotoxigenic E. coli (47%), uropathogenic E. coli (2%), neonatal meningitis E. coli (5%), diffusely adherent E. coli (1%) and enterohaemorrhagic E. coli (1%). Interestingly, enteroinvasive and enteroaggregative E. coli were not detected. The phenotypic antibiogram profiles of the isolates revealed that all were resistant to penicillin G, while 98% and 38% of the pathotypes were resistant to ampicillin and trimethoprim-sulphamethoxazole, respectively. About 8% of the isolates were resistant to streptomycin. More than half of the isolates exhibited multiple antibiotic resistance with 44% being resistant to three antibiotics and 8% resistant to four antibiotics. We conclude that the Kat River is a reservoir of potentially virulent antibiotic resistant E. coli strains that can cause serious health risks to humans who drink raw water from this river, or in the case that consumption of treated drinking water coincides with failed drinking water processes. PMID:25119699

Nontongana, Nolonwabo; Sibanda, Timothy; Ngwenya, Elvis; Okoh, Anthony I

2014-08-01

164

Controlling the Shape of Filamentous Cells of Escherichia coli  

E-print Network

Controlling the Shape of Filamentous Cells of Escherichia coli Shoji Takeuchi,, Willow R. Di of Escherichia coli with defined shapes, including crescents, zigzags, sinusoids, and spirals. The procedure into solution. This paper describes a technique for controlling the shape of filamentous cells of Escherichia

Weibel, Douglas B.

165

Genetic architecture of thermal adaptation in Escherichia coli  

E-print Network

Genetic architecture of thermal adaptation in Escherichia coli Michelle M. Riehle*, Albert F make genomewide surveys more tractable. Six lines of Escherichia coli adapted for 2,000 generations events. Three of the duplications were at 2.85 Mb of the E. coli chromo- some, providing evidence

Bennett, Albert F.

166

Controlling biological systems: the lactose regulation system of Escherichia coli  

E-print Network

Controlling biological systems: the lactose regulation system of Escherichia coli A. Agung Julius, namely, the lactose regulation system of the Escherichia coli bacteria. The conceptual idea behind hybrid model of the lactose regulation system of E. coli bacteria that capture important phenomena which

Pappas, George J.

167

EXPERIMENTAL ESCHERICHIA COLI DIARRHOEA IN COLOSTRUM DEPRIVED LAMBS  

E-print Network

EXPERIMENTAL ESCHERICHIA COLI DIARRHOEA IN COLOSTRUM DEPRIVED LAMBS Marion DUCHET-SUCHAUX, Anne Escherichia coli (ETEC), is an important cause of mortality in calves, lambs and piglets. ETEC strains) élevés conventionnellement sans colostrum ont été inoculés par voie orale avec 1,7 à 3,1 x 108 E. coli B

Boyer, Edmond

168

Original article Inhibition of Escherichia coli O157:H7  

E-print Network

Original article Inhibition of Escherichia coli O157:H7 in commercial and traditional fermented and indigenous lactic acid bacteria (LAB) and the survival of Escherichia coli O157:H7 in fermented goat's milk to growth and acid production. However, E. coli O157:H7 was inhibited in the LP-activated milk

Paris-Sud XI, Université de

169

ORIGINAL ARTICLE Escherichia coli transcription factor YncC  

E-print Network

ORIGINAL ARTICLE Escherichia coli transcription factor YncC (McbR) regulates colanic acid, USA Quorum-sensing signal autoinducer 2 (AI-2) stimulates Escherichia coli biofilm formation through synthase LuxS and B3023 repressed yncC. MqsR has a toxic effect on E. coli bacterial growth, which

Wood, Thomas K.

170

Probing the Performance Limits of the Escherichia coli Metabolic Network  

E-print Network

Probing the Performance Limits of the Escherichia coli Metabolic Network Subject to Gene Additions to a linear flux balance analysis (FBA) Escherichia coli model. Both the gene addition problem of optimally necessary to achieve maximum biomass production in E. coli is determined for aerobic growth on glucose

Maranas, Costas

171

Response of Escherichia coli growth rate to osmotic shock  

E-print Network

Response of Escherichia coli growth rate to osmotic shock Enrique Rojasa,b,c , Julie A. Theriotb monitored the elongation of single Escherichia coli cells while rapidly chang- ing the osmolarity- and hypoosmotic shock, E. coli cells resumed their preshock growth rate and relaxed to their steady-state rate

Das, Rhiju

172

Characterization of enteroaggregative Escherichia coli isolates  

Microsoft Academic Search

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

Chantal Rich; Sabine Favre-Bonte; Frédéric Sapena; Bernard Joly; Christiane Forestier

1999-01-01

173

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. PMID:22873125

Brumbaugh, Ariel R; Mobley, Harry LT

2012-01-01

174

Virulence determinants in Escherichia coli associated with recurrent cystitis in sexually active women.  

PubMed

More than a quarter of women who experience acute cystitis develop recurrence but information on specific urovirulent genetic profile of uropathogenic Escherichia coli associated with recurrent cystitis is still limited. In this prospective cohort study, index episode E. coli from a cohort of 46 sexually active women with acute cystitis who reported recurrence during followup were grouped into repeat infection (RI) and single infection (SI) isolates, based on enterobacterial repetitive intergenic consensus (ERIC) PCR profile comparison with subsequent E. coli isolated from same women. PCR for phylogrouping and 15 virulence genes along with test for biofilm formation were done. Virulence score was calculated for each isolate as number of virulence genes detected. Among 46 index E. coli, 22 were RI, and 24 were SI isolates. RI isolates had phylogroup B2 as majority (54.5%) which is typically described as more virulent phylogroup and virulence score for RI isolates was also significantly higher compared to SI isolates. Virulence gene malX (p = 0.03) was significantly associated with RI isolates. 68.2% RI isolates were strong to moderate biofilm producers in comparison to 33.3% SI isolates, an important survival strategy to reside in bladder and or vagina. Overall, E. coli associated with recurrent cystitis appear to be more virulent and malX seems to have a role in causing repeat infection. PMID:25107739

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

2014-09-01

175

Action of sodium deoxycholate on Escherichia coli  

SciTech Connect

Sodium deoxycholate is used in a number of bacteriological media for the isolation and classification of gram-negative bacteria from food and the environment. Initial experiments to study the effect of deoxycholate on the growth parameters of Escherichia coli showed an increase in the lag time constant and generation time and a decrease in the growth rate constant total cell yield of this microorganisms. Cell fractionation studies indicated that sodium deoxycholate at levels used in bacteriological media interferes with the incorporation of (U-/sup 14/C)glucose into the cold-trichloroacetic acid-soluble, ethanol-soluble, and trypsin-soluble cellular fractions of E. coli. Finally, sodium deoxycholate interfered with the flagellation and motility of Proteus mirabilis and E. coli. It would appear then that further improvement of the deoxycholate medium may be in order.

D'Mello, A.; Yotis, W.W.

1987-08-01

176

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. PMID:11729263

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

2001-01-01

177

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

PubMed

Escherichia coli is the most common pathogen causing acute cystitis in sexually active women. Human faeces are generally considered the primary reservoir for infection and the faecal-perineal-urethral pathway is the accepted route of infection. Two theories have been proposed for the pathogenesis of acute cystitis: (1) special pathogenicity, where uropathogenic E. coli (UPEC) encoding special virulence factors causes infection; and (2) prevalence, wherein ordinary faecal E. coli causes infection by simple mass action. The aim of this study was to compare concurrent urinary E. coli isolates from women with acute cystitis with their own dominant faecal, vaginal E. coli isolates; thus, these patients served as their own control. E. coli isolates from 80 women were analysed by phylotyping, virulence profiling (for 15 putative virulence genes) and enterobacterial repetitive intergenic consensus (ERIC) PCR. A virulence score was calculated for each isolate based on the number of virulence genes detected. Four host ecological groups of E. coli were created on the basis of ERIC PCR: group UVF, where vaginal and faecal isolates yielded the infecting urine clone; group UV, where only vaginal isolates yielded the infecting urine clone; group UF, where faecal isolates yielded the infecting urine clone; and group U, where the infecting urine clone was distinct. In the majority of cases the infecting E. coli clone from urine was also the dominant faecal clone (56.3%; groups UVF and UF possessing high virulence scores of 4.6 and 3.9, respectively), indicating that both mechanisms play a role in pathogenesis. Non-dominant yet virulent faecal clones or an external source of E. coli seems a possibility in the UV group (13.7%, VF score 4.8). In 30% of patients (U group) the infecting urine clone was non-dominant and possessed a low virulence score (2.7); suggesting a possible role for host factors in establishing infection. PMID:24899598

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

2014-08-01

178

Salmonella typhimurium intercepts Escherichia coli signaling to enhance antibiotic tolerance  

E-print Network

Salmonella typhimurium intercepts Escherichia coli signaling to enhance antibiotic tolerance Nicole Salmonella typhimurium increases its antibiotic toler- ance in response to indole, even though S. typhimurium

Collins, James J.

179

The Genetic Basis of Escherichia coli Pathoadaptation to Macrophages  

E-print Network

of the E. coli yrfF gene. Moreover, transposition of the IS186 element into the promoter of Lon gene fast, and through how many adaptive steps, a commensal Escherichia coli (E. coli) acquire, as suggested from a mathematical model, which reproduces the observed experimental dynamics of E. coli

Magalhães, Sara

180

Insights on Escherichia coli biofilm formation and inhibition from whole-transcriptome profiling  

E-print Network

Minireview Insights on Escherichia coli biofilm formation and inhibition from whole with the best- characterized strain, Escherichia coli. Investigations of biofilm formation and inhibition). Escherichia coli biofilm development is a complex process that leads to beautiful structures (Fig. 1

Wood, Thomas K.

181

Construction and Optimization of Mevalonate Pathway for Production of Isoprenoids in Escherichia coli  

E-print Network

Escherichia coli evolve to computationally predicted growthF.G. , B. Growth-rate recovery of Escherichia coli culturesEscherichia coli K-12 undergoes adaptive evolution to achieve in silico predicted optimal growth.

Nowroozi, Farnaz F.B.

2010-01-01

182

Survival of multi-drug resistant enteropathogenic Escherichia coli and Salmonella paratyphi in Vembanadu  

E-print Network

Survival of multi-drug resistant enteropathogenic Escherichia coli and Salmonella paratyphi the survival response of multi-drug resistant enteropathogenic Escherichia coli and Salmonella paratyphi- otypes of Escherichia coli, Salmonella enterica typhi and paratyphi are highly endemic to India

Mazumder, Asit

183

Intestinal immunisation with Escherichia coli protects rats against Escherichia coli induced cholangitis.  

PubMed Central

BACKGROUND: Cholangitis, an infection of the biliary tract, is most commonly caused by Gram negative bacteria, particularly Escherichia coli. Factors governing the severity of cholangitis, including the role of biliary IgA, are poorly understood. AIMS: The aim of this work was to find out if biliary IgA directed against E coli protects rats against hepatobiliary infection with E coli. SUBJECTS: Male Sprague-Dawley rats weighing 270-350 grams were used in all of the experiments. METHODS: At laparotomy, rats were immunised by injecting killed E coli or normal saline (controls) into Peyer's patches. With or without subsequent antigenic boosting (by oral administration of killed E coli), bile was collected at a second laparotomy, and rats were infected by introducing viable E coli into the bile duct. Production of IgA anti-E coli antibody was measured by enzyme linked immunosorbent assay of bile, and the presence of hepatobiliary infection was determined by quantitative culture of liver homogenates. RESULTS: Systemic infection was present in six of 12 control rats and in one of 24 immunised rats (p = 0.005) after death. There was an inverse correlation between immunisation and E coli colony counts in cultured liver homogenates (p = 0.024). CONCLUSION: The findings suggest that biliary IgA directed against E coli protected rats against hepatobiliary E coli infection and systemic sepsis. Images Figure 2 PMID:8881825

Aagaard, B D; Heyworth, M F; Oesterle, A L; Jones, A L; Way, L W

1996-01-01

184

An isochorismate hydroxymutase isogene in Escherichia coli.  

PubMed

The pivotal step in enterobactin and menaquinone biosynthesis is the conversion of chorismate to isochorismate. Circumstantial evidence pointed to Escherichia coli isochorismate hydroxymutase isogenes being responsible for this conversion. While the gene involved in enterobactin synthesis (entC) was known, the corresponding gene for menaquinone biosynthesis (menF) was not but has now been identified and sequenced. The amino acid sequence of MenF is 23.5% identical and 57.8% similar to that of EntC. PMID:8549818

Müller, R; Dahm, C; Schulte, G; Leistner, E

1996-01-01

185

Fluoroquinolone-resistant Escherichia coli, Indonesia  

PubMed Central

In a recent, population-based survey of 3,996 persons in Indonesia, fluoroquinolone (FQ)-resistant Escherichia coli was prevalent in the fecal flora of 6% of patients at hospital admission and 23% of patients at discharge, but not among healthy relatives or patients visiting primary healthcare centers (2%). Molecular typing showed extensive genetic diversity with only limited clonality among isolates. This finding suggests that independent selection of resistant mutants occurs frequently. FQ-resistant isolates exhibited a higher rate of spontaneous mutation, but sparser virulence profiles, than FQ-susceptible isolates from the same population. The resistant isolates belonged predominantly to phylogenetic groups A (57%) and B1 (22%) but also to the moderately virulent group D (20%). Hypervirulent strains from the B2 cluster were underrepresented (1%). Because FQ-resistant E. coli can cause disease, especially nosocomial infections in immunocompromised patients, spread of such strains must be stopped. PMID:16229763

Kuntaman, Kuntaman; Lestari, Endang Sri; Severin, Juliette A.; Kershof, Irma M.; Mertaniasih, Ni Made; Purwanta, Marijam; Hadi, Usman; Johnson, James R.; Verbrugh, Henri A.

2005-01-01

186

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

187

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.

188

Investigation of Escherichia Coli bacteria growth process using electronic nose  

Microsoft Academic Search

In this study, the kind of Escherichia Coli obtained using gas sensor sequence consisted deneyler QCM (Quartz Crystal Microbalance) as experiments related to determining from the odour of growing duration of the bacteria. In this context, the growing duration of odour produced by Escherichia Coli bacteria was examined in five day period after 24, 48, 72, 96, 120 hours that

M. E. S?ahin; H. M. Saraog?lu

2010-01-01

189

Kefir grain tolerance to Escherichia coli contamination--industrial advantages  

E-print Network

NOTE Kefir grain tolerance to Escherichia coli contamination--industrial advantages Piotr / Published online: 21 August 2012 # INRA and Springer-Verlag, France 2012 Abstract Kefir grains are used the possibility of the re-use of kefir grains grown at 18 °C for 24 h in pasteurized Escherichia coli contaminated

Paris-Sud XI, Université de

190

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

191

Both Host and Pathogen Factors Predispose to Escherichia coli Urinary-Source Bacteremia in Hospitalized Patients  

PubMed Central

Background.?The urinary tract is the most common source for Escherichia coli bacteremia. Mortality from E. coli urinary-source bacteremia is higher than that from urinary tract infection. Predisposing factors for urinary-source E. coli bacteremia are poorly characterized. Methods.?In order to identify urinary-source bacteremia risk factors, we conducted a 12-month prospective cohort study of adult inpatients with E. coli bacteriuria that were tested for bacteremia within ±1 day of the bacteriuria. Patients with bacteremia were compared with those without bacteremia. Bacterial isolates from urine were screened for 16 putative virulence genes using high-throughput dot-blot hybridization. Results.?Twenty-four of 156 subjects (15%) had E. coli bacteremia. Bacteremic patients were more likely to have benign prostatic hyperplasia (56% vs 19%; P = .04), a history of urogenital surgery (63% vs 28%; P = .001), and presentation with hesitancy/retention (21% vs 4%; P = .002), fever (63% vs 38%; P = .02), and pyelonephritis (67% vs 41%; P = .02). The genes kpsMT (group II capsule) (17 [71%] vs 62 [47%]; P = .03) and prf (P-fimbriae family) (13 [54%] vs 40 [30%]; P = .02) were more frequent in the urinary strains from bacteremic patients. Symptoms of hesitancy/retention (odds ratio [OR], 7.8; 95% confidence interval [CI], 1.6–37), history of a urogenital procedure (OR, 5.4; 95% CI, 2–14.7), and presence of kpsMT (OR, 2.9; 95% CI, 1–8.2) independently predicted bacteremia. Conclusions.?Bacteremia secondary to E. coli bacteriuria was frequent (15%) in those tested for it. Urinary stasis, surgical disruption of urogenital tissues, and a bacterial capsule characteristic contribute to systemic invasion by uropathogenic E. coli. PMID:22431806

Marschall, Jonas; Zhang, Lixin; Foxman, Betsy; Warren, David K.; Henderson, Jeffrey P.

2012-01-01

192

Phenotypic and Molecular Characterization of Extended-Spectrum Beta-Lactamase-Producing Escherichia coli in Bangladesh  

PubMed Central

Background Resistance to cephalosporins in Enterobacteriaceae is mainly due to the production of extended-spectrum beta-lactamase (ESBL). Little is known about ESBL-producing bacteria in Bangladesh. Therefore, the study presents results of phenotypic and molecular characterization of ESBL-producing Escherichia coli from hospitals in Bangladesh. Methods A total of 339 E. coli isolated from patients with urinary tract and wound infections attending three different medical hospitals in urban and rural areas of Bangladesh between 2003–2007 were screened for ESBL-production by the double disk diffusion test. Isolates with ESBL-phenotype were further characterized by antibiotic susceptibility testing, PCR and sequencing of different ?-lactamase and virulence genes, serotyping, and XbaI-macrorestriction followed by pulsed-field gel electrophoresis (PFGE). Results We identified 40 E. coli with ESBL phenotype. These isolates were resistant to ceftriaxone, ceftazidime, cefotaxime, aztreonam, cefepime, and nalidixic acid but remained susceptible to imipenem. All but one isolate were additionally resistant to ciprofloxacin, and 3 isolates were resistant to cefoxitin. ESBL genes of blaCTX-M-1-group were detected in all isolates; blaTEM-type and blaOXA-1-type genes were detected in 33 (82.5%) and 19 (47.5%) isolates, respectively. Virulence genes that are present in diarrhoeagenic E. coli were not found. Class-1 integron was present in 20 (50%) isolates. All the ESBL-producing E. coli isolates harbored plasmids ranging between 1.1 and 120 MDa. PFGE-typing revealed 26 different pulsotypes, but identical pulsotype showed 6 isolates of serotype O25:H4. Conclusion The prevalence of multidrug-resistant ESBL-producing E. coli isolates appears to be high and the majority of the isolates were positive for blaCTX-M. Although there was genetic heterogeneity among isolates, presence of a cluster of isolates belonging to serotype O25:H4 indicates dissemination of the pandemic uropathogenic E. coli clone in Bangladesh. PMID:25302491

Lina, Taslima T.; Khajanchi, Bijay K.; Azmi, Ishrat J.; Islam, Mohammad Aminul; Mahmood, Belal; Akter, Mahmuda; Banik, Atanu; Alim, Rumana; Navarro, Armando; Perez, Gabriel; Cravioto, Alejandro; Talukder, Kaisar A.

2014-01-01

193

www.postersession.com Characterization of the Omptin Protease, OmpT, in Escherichia coli  

E-print Network

printed by www.postersession.com Characterization of the Omptin Protease, OmpT, in Escherichia coli Escherichia coliEscherichia coli,, Shigella flexneriShigella flexneri,, Salmonella. ·· InIn E. coliE. coli, OmpT has been shown to cleave protamine, an antimicrobial pept, OmpT has been

Walker, Lawrence R.

194

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

195

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 1,500 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

196

Selection footprint in the FimH adhesin shows pathoadaptive niche differentiation in Escherichia coli.  

PubMed

Spread of biological species from primary into novel habitats leads to within-species adaptive niche differentiation and is commonly driven by acquisition of point mutations in individual genes that increase fitness in the alternative environment. However, finding footprints of adaptive niche differentiation in specific genes remains a challenge. Here we describe a novel method to analyze the footprint of pathogenicity-adaptive, or pathoadaptive, mutations in the Escherichia coli gene encoding FimH-the major, mannose-sensitive adhesin. Analysis of distribution of mutations across the nodes and branches of the FimH phylogenetic network shows (1) zonal separation of evolutionary primary structural variants of FimH and recently derived ones, (2) dramatic differences in the ratio of synonymous and nonsynonymous changes between nodes from different zones, (3) evidence for replacement hot-spots in the FimH protein, (4) differential zonal distribution of FimH variants from commensal and uropathogenic E. coli, and (5) pathoadaptive functional changes in FimH brought by the mutations. The selective footprint in fimH indicates that the pathoadaptive niche differentiation of E. coli is either in its initial stages or undergoing an evolutionary "source/sink" dynamic. PMID:15044596

Sokurenko, Evgeni V; Feldgarden, Michael; Trintchina, Elena; Weissman, Scott J; Avagyan, Serine; Chattopadhyay, Sujay; Johnson, James R; Dykhuizen, Daniel E

2004-07-01

197

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. PMID:7806371

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

1995-01-01

198

Sources of Escherichia coli in a Coastal Subtropical Environment  

Microsoft Academic Search

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

HELENA M. SOLO-GABRIELE; MELINDA A. WOLFERT; TIMOTHY R. DESMARAIS; CAROL J. PALMER

2000-01-01

199

Review article Secretion of virulence factors by Escherichia coli  

E-print Network

Review article Secretion of virulence factors by Escherichia coli Bernard China* Fréderic Goffaux with their host, pathogenic strains of E. coli need to secrete some virulence factors which can modify the metabolism of host cells, contributing to disease. Since E. coli is a Gram-negative bacteria, this secretion

Paris-Sud XI, Université de

200

CONFINEMENT BY BIASED VELOCITY JUMPS: AGGREGATION OF ESCHERICHIA COLI  

E-print Network

CONFINEMENT BY BIASED VELOCITY JUMPS: AGGREGATION OF ESCHERICHIA COLI VINCENT CALVEZ, GA¨EL RAOUL-attractors. The prototypical example is the bacterium Escheria coli, whose swimming pattern has been described as run, this stochastic process is biased upwards the gradient, although E. coli is too small to reliably measure

Schmeiser, Christian

201

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

202

Indole Transport across Escherichia coli Membranes ?  

PubMed Central

Indole has many, diverse roles in bacterial signaling. It regulates the transition from exponential to stationary phase, it is involved in the control of plasmid stability, and it influences biofilm formation, virulence, and stress responses (including antibiotic resistance). Its role is not restricted to bacteria, and recently it has been shown to include mutually beneficial signaling between enteric bacteria and their mammalian hosts. In many respects indole behaves like the signaling component of a quorum-sensing system. Indole synthesized within the producer bacterium is exported into the surroundings where its accumulation is detected by sensitive cells. A view often repeated in the literature is that in Escherichia coli the AcrEF-TolC and Mtr transporter proteins are involved in the export and import, respectively, of indole. However, the evidence for their involvement is indirect, and it has been known for a long time that indole can pass directly through a lipid bilayer. We have combined in vivo and in vitro approaches to examine the relative importance of protein-mediated transport and direct passage across the E. coli membrane. We conclude that the movement of indole across the E. coli membrane under normal physiological conditions is independent of AcrEF-TolC and Mtr. Furthermore, direct observation of individual liposomes shows that indole can rapidly cross an E. coli lipid membrane without the aid of any proteinaceous transporter. These observations not only enhance our understanding of indole signaling in bacteria but also provide a simple explanation for the ability of indole to signal between biological kingdoms. PMID:21296966

Pinero-Fernandez, S.; Chimerel, C.; Keyser, U. F.; Summers, D. K.

2011-01-01

203

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. PMID:21233598

TAKEDA, Yoshifumi

2011-01-01

204

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

205

Mechanism of Escherichia coli Resistance to Pyrrhocoricin  

PubMed Central

Due to their lack of toxicity to mammalian cells and good serum stability, proline-rich antimicrobial peptides (PR-AMPs) have been proposed as promising candidates for the treatment of infections caused by antimicrobial-resistant bacterial pathogens. It has been hypothesized that these peptides act on multiple targets within bacterial cells, and therefore the likelihood of the emergence of resistance was considered to be low. Here, we show that spontaneous Escherichia coli mutants resistant to pyrrhocoricin arise at a frequency of approximately 6 × 10?7. Multiple independently derived mutants all contained a deletion in a nonessential gene that encodes the putative peptide uptake permease SbmA. Sensitivity could be restored to the mutants by complementation with an intact copy of the sbmA gene. These findings question the viability of the development of insect PR-AMPs as antimicrobials. PMID:24590485

Narayanan, Shalini; Modak, Joyanta K.; Ryan, Catherine S.; Garcia-Bustos, Jose; Davies, John K.

2014-01-01

206

Intrahost genome alterations in enterohemorrhagic Escherichia coli.  

PubMed

Bacterial chromosomes are not fixed molecules; they evolve over the course of infections in human beings. During infection, a variety of strong selective pressures are exerted on the pathogen. The resulting genetic changes that occur in intestinal pathogens might influence clinical outcome and have an impact on diagnosis and epidemiology. Enterohemorrhagic Escherichia coli (EHEC) is a good example of this process. These zoonotic pathogens cause diarrhea, bloody diarrhea, and hemolytic uremic syndrome in human beings, whereas in their natural habitat they mostly are asymptomatic colonizers. Thus, EHEC must be able to quickly adapt from one milieu to another. The greatest challenge it might face is to infect human beings--profound chromosomal changes occur during the brief period that EHEC passes through the human gastrointestinal tract, leading to gains and losses of virulence determinants. The intensive study of human enteric factors that induce or modulate pathogen chromosome instability could provide important information about host-microbial interactions. PMID:19462505

Mellmann, Alexander; Bielaszewska, Martina; Karch, Helge

2009-05-01

207

Nucleoid release from Escherichia coli cells.  

PubMed Central

The time course of morphological changes during lysis of Escherichia coli cells was examined with respect to an undisturbed release of nucleoids. The addition of detergents to plasmolyzed, osmotic sensitive cells resulted in the immediate reversal of plasmolysis followed by the appearance of rod-shaped ghost cells without any detectable spheroplast formation. Electron microscopic examination of the rod-shaped ghost cells revealed a zonal gap in the cell envelope, allowing the free release of the nucleoid. Due to the high ionic strength, a suitable cell lysis was shown to require higher incubation temperatures. However, in the absence of an appropriate control this may result in the sphering and vesiculation of ghost cell envelopes and even the unfolding of released nucleoids. To avoid this unfavorable consequence of lysis at high temperatures, a microscopic examination on the course of rod-shaped ghost formation is suggested. Images PMID:342512

Materman, E C; Van Gool, A P

1978-01-01

208

Dispensability of Escherichia coli's latent pathways  

E-print Network

Gene-knockout experiments on single-cell organisms have established that expression of a substantial fraction of genes is not needed for optimal growth. This problem acquired a new dimension with the recent discovery that environmental and genetic perturbations of the bacterium Escherichia coli are followed by the temporary activation of a large number of latent metabolic pathways, which suggests the hypothesis that temporarily activated reactions impact growth and hence facilitate adaptation in the presence of perturbations. Here we test this hypothesis computationally and find, surprisingly, that the availability of latent pathways consistently offers no growth advantage, and tends in fact to inhibit growth after genetic perturbations. This is shown to be true even for latent pathways with a known function in alternate conditions, thus extending the significance of this adverse effect beyond apparently nonessential genes. These findings raise the possibility that latent pathway activation is in fact derivat...

Cornelius, Sean P; Motter, Adilson E; 10.1073/pnas.1009772108

2011-01-01

209

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

210

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

211

Independence of replisomes in Escherichia coli chromosomalreplication  

SciTech Connect

In Escherichia coli DNA replication is carried out by the coordinated action of the proteins within a replisome. After replication initiation, the two bidirectionally oriented replisomes from a single origin are colocalized into higher-order structures termed replication factories. The factory model postulated that the two replisomes are also functionally coupled. We tested this hypothesis by using DNA combing and whole-genome microarrays. Nascent DNA surrounding oriC in single, combed chromosomes showed instead that one replisome, usually the leftward one, was significantly ahead of the other 70% of the time. We next used microarrays to follow replication throughout the genome by measuring DNA copy number. We found in multiple E. coli strains that the replisomes are independent, with the leftward replisome ahead of the rightward one. The size of the bias was strain-specific, varying from 50 to 130 kb in the array results. When we artificially blocked one replisome, the other continued unabated, again demonstrating independence. We suggest an improved version of the factory model that retains the advantages of threading DNA through colocalized replisomes at about equal rates, but allows the cell flexibility to overcome obstacles encountered during elongation.

Breier, Adam M.; Weier, Heinz-Ulrich G.; Cozzarelli, Nicholas R.

2005-03-13

212

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

213

Rates of transposition in Escherichia coli  

PubMed Central

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

2013-01-01

214

Concerted control of Escherichia coli cell division  

PubMed Central

The coordination of cell growth and division is a long-standing problem in biology. Focusing on Escherichia coli in steady growth, we quantify cell division control using a stochastic model, by inferring the division rate as a function of the observable parameters from large empirical datasets of dividing cells. We find that (i) cells have mechanisms to control their size, (ii) size control is effected by changes in the doubling time, rather than in the single-cell elongation rate, (iii) the division rate increases steeply with cell size for small cells, and saturates for larger cells. Importantly, (iv) the current size is not the only variable controlling cell division, but the time spent in the cell cycle appears to play a role, and (v) common tests of cell size control may fail when such concerted control is in place. Our analysis illustrates the mechanisms of cell division control in E. coli. The phenomenological framework presented is sufficiently general to be widely applicable and opens the way for rigorous tests of molecular cell-cycle models. PMID:24550446

Osella, Matteo; Nugent, Eileen; Cosentino Lagomarsino, Marco

2014-01-01

215

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

216

Chemotaxis Toward Sugars in Escherichia coli  

PubMed Central

Using a quantitative assay for measuring chemotaxis, we tested a variety of sugars and sugar derivatives for their ability to attract Escherichia coli bacteria. The most effective attractants, i.e., those that have thresholds near 10?5 M or below, are N-acetyl-d-glucosamine, 6-deoxy-d-glucose, d-fructose, d-fucose, 1-d-glycerol-?-d-galactoside, galactitol, d-galactose, d-glucosamine, d-glucose, ?-d-glucose-1-phosphate, lactose, maltose, d-mannitol, d-mannose, methyl-?-d-galactoside, methyl-?-d-glucoside, d-ribose, d-sorbitol, and trehalose. Lactose, and probably d-glucose-1-phosphate, are attractive only after conversion to the free monosaccharide, while the other attractants do not require breakdown for taxis. Nine different chemoreceptors are involved in detecting these various attractants. They are called the N-acetyl-glucosamine, fructose, galactose, glucose, maltose, mannitol, ribose, sorbitol, and trehalose chemoreceptors; the specificity of each was studied. The chemoreceptors, with the exception of the one for d-glucose, are inducible. The galactose-binding protein serves as the recognition component of the galactose chemoreceptor. E. coli also has osmotically shockable binding activities for maltose and d-ribose, and these appear to serve as the recognition components for the corresponding chemoreceptors. PMID:4580570

Adler, Julius; Hazelbauer, Gerald L.; Dahl, M. M.

1973-01-01

217

Variation in the propensity to diversify in experimental populations of Escherichia coli: consequences  

E-print Network

displacement, diversification, Escherichia coli, growth curve analysis, metabolism, mutational bias. [UVariation in the propensity to diversify in experimental populations of Escherichia coli-switcher genotypes (reflecting different specialized metabolic phenotypes) derived from the bacterium Escherichia

Doebeli, Michael

218

Pathogenic Escherichia coli strain discrimination using laser-induced breakdown spectroscopy  

E-print Network

Pathogenic Escherichia coli strain discrimination using laser-induced breakdown spectroscopy A pathogenic strain of bacteria, Escherichia coli O157:H7 enterohemorrhagic E. coli or EHEC , has been analyzed with both nanosecond and femtosecond laser pulses to identify the Escherichia coli bacterium.10­12 E. coli

Rehse, Steven J.

219

Escherichia coli cyclopropane fatty acid synthase.  

PubMed

Escherichia coli fatty acid cyclopropane synthase (CFAS) was overproduced and purified as a His6-tagged protein. This recombinant enzyme is as active as the native enzyme with a Km of 90 microm for S-AdoMet and a specific activity of 5 x 10(-2) micromol.min(-1).mg(-1). The enzyme is devoid of organic or metal cofactors and is unable to catalyze the wash-out of the methyl protons of S-AdoMet to the solvent, data that do not support the ylide mechanism. Inactivation of the enzyme by 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB), a pseudo first-order process with a rate constant of 1.2 m(-1).s(-1), is not protected by substrates. Graphical analysis of the inactivation by DTNB revealed that only one cysteine is responsible for the inactivation of the enzyme. The three strictly conserved Cys residues among cyclopropane synthases, C139, C176 and C354 of the E. coli enzyme, were mutated to serine. The relative catalytic efficiency of the mutants were 16% for C139S, 150% for C176S and 63% for C354S. The three mutants were inactivated by DTNB at a rate comparable to the rate of inactivation of the His6-tagged wild-type enzyme, indicating that the Cys responsible for the loss of activity is not one of the conserved residues. Therefore, none of the conserved Cys residues is essential for catalysis and cannot be involved in covalent catalysis or general base catalysis. The inactivation is probably the result of steric hindrance, a phenomenon irrelevant to catalysis. It is very likely that E. coli CFAS operates via a carbocation mechanism, but the base and nucleophile remain to be identified. PMID:15606764

Courtois, Fabienne; Guérard, Christine; Thomas, Xavier; Ploux, Olivier

2004-12-01

220

Survival of Escherichia coli in two sewage treatment plants using UV irradiation and chlorination for disinfection.  

PubMed

We investigated the survival of Escherichia coli in two STPs utilising UV irradiation (STP-A) or chlorination (STP-B) for disinfection. In all, 370 E. coli strains isolated from raw influent sewage (IS), secondary treated effluent (STE) and effluent after the disinfection processes of both STPs were typed using a high resolution biochemical fingerprinting method and were grouped into common (C-) and single (S-) biochemical phenotypes (BPTs). In STP-A, 83 BPTs comprising 123 isolates were found in IS and STE, of which 7 BPTs survived UV irradiation. Isolates tested from the same sites of STP-B (n = 220) comprised 122 BPTs, however, only two BPTs were found post-chlorination. A representative isolate from each BPT from both STPs was tested for the presence of 11 virulence genes (VGs) associated with uropathogenic (UPEC) or intestinal pathogenic (IPEC) E. coli strains. Strains surviving UV irradiation were distributed among seven phylogenetic groups with five BPTs carrying VGs associated with either UPEC (4 BPTs) or IPEC (1 BPT). In contrast, E. coli strains found in STP-B carried no VGs. Strains from both STPs were resistant to up to 12 out of the 21 antibiotics tested but there was no significant difference between the numbers of antibiotics to which surviving strains were resistant to in these STPs. Our data suggests that some E. coli strains have a better ability to survive STPs utilising chlorination and UV irradiation for disinfection. However, strains that survive UV irradiation are more diverse and may carry more VGs than those surviving SPTs using chlorination. PMID:24091189

Anastasi, E M; Wohlsen, T D; Stratton, H M; Katouli, M

2013-11-01

221

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. PMID:24833052

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

222

Phylogenetic grouping and pathotypic comparison of urine and fecal Escherichia coli isolates from children with urinary tract infection  

PubMed Central

The aim of this study was to investigate the phylogenetic background and to assess hlyD (involved in the secretion of haemolysin A) and intI1 (encoding a class 1 integrase) in Escherichia coli isolates derived from urinary and fecal specimens. A total of 200 E. coli isolates was collected from patients presenting with urinary tract infection (UTI) during September 2009 to September 2010 and screened for hlyD and intI1 genes by polymerase chain reaction (PCR). Phylogenetic analysis showed that E. coli is composed of four main phylogenetic groups (A, B1, B2 and D) and that uropathogenic E. coli (UPEC) isolates mainly belong to groups B2 (54%) and D (34%) whereas group A (44%) and D (26%) are predominant among commensal E. coli isolates. In this study, hlyD was present in 26% of UPEC and 2% of commensal E. coli isolates. However, hemolytic activity was detected for 42% of UPEC and 6% of commensal E. coli isolates (p < 0.05). intI1 gene was more frequently expressed in UPEC (24%) in comparison with commensal E. coli isolates (12%). Resistance to aztreonam, co-trimoxazole and cefpodoxime were frequently found among UPEC isolates whereas commensal E. coli isolates were commonly resistant to co-trimoxazole, nalidixic acid and cefotaxime. Concluding, a considerable difference between UPEC and commensal E. coli isolates was observed regarding their phylogenetic groups, presence of class 1 integron and hlyD gene, hemolysin activity and resistance pattern. The detection of class 1 integrons and hlyD gene was higher among UPEC compared with commensal E. coli isolates. These findings may contribute for a better understanding of the factors involved in the pathogenesis of UPEC. PMID:25242935

Navidinia, Masoumeh; Peerayeh, Shahin Najar; Fallah, Fatemeh; Bakhshi, Bita; Sajadinia, Raheleh Sadat

2014-01-01

223

Y-family DNA polymerases in Escherichia coli  

E-print Network

The observation that mutations in the Escherichia coli genes umuC+ and umuD+ abolish mutagenesis induced by UV light strongly supported the counterintuitive notion that such mutagenesis is an active rather than passive ...

Jarosz, Daniel F.

224

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...

225

The N-degradome of Escherichia coli  

PubMed Central

The N-end rule is a conserved mechanism found in Gram-negative bacteria and eukaryotes for marking proteins to be degraded by ATP-dependent proteases. Specific N-terminal amino acids (N-degrons) are sufficient to target a protein to the degradation machinery. In Escherichia coli, the adaptor ClpS binds an N-degron and delivers the protein to ClpAP for degradation. As ClpS recognizes N-terminal Phe, Trp, Tyr, and Leu, which are not found at the N terminus of proteins translated and processed by the canonical pathway, proteins must be post-translationally modified to expose an N-degron. One modification is catalyzed by Aat, an enzyme that adds leucine or phenylalanine to proteins with N-terminal lysine or arginine; however, such proteins are also not generated by the canonical protein synthesis pathway. Thus, the mechanisms producing N-degrons in proteins and the frequency of their occurrence largely remain a mystery. To address these issues, we used a ClpS affinity column to isolate interacting proteins from E. coli cell lysates under non-denaturing conditions. We identified more than 100 proteins that differentially bound to a column charged with wild-type ClpS and eluted with a peptide bearing an N-degron. Thirty-two of 37 determined N-terminal peptides had N-degrons. Most of the proteins were N-terminally truncated by endoproteases or exopeptidases, and many were further modified by Aat. The identities of the proteins point to possible physiological roles for the N-end rule in cell division, translation, transcription, and DNA replication and reveal widespread proteolytic processing of cellular proteins to generate N-end rule substrates. PMID:23960079

Humbard, Matthew A.; Surkov, Serhiy; De Donatis, Gian Marco; Jenkins, Lisa M.; Maurizi, Michael R.

2013-01-01

226

The Escherichia coli peripheral inner membrane proteome.  

PubMed

Biological membranes are essential for cell viability. Their functional characteristics strongly depend on their protein content, which consists of transmembrane (integral) and peripherally associated membrane proteins. Both integral and peripheral inner membrane proteins mediate a plethora of biological processes. Whereas transmembrane proteins have characteristic hydrophobic stretches and can be predicted using bioinformatics approaches, peripheral inner membrane proteins are hydrophilic, exist in equilibria with soluble pools, and carry no discernible membrane targeting signals. We experimentally determined the cytoplasmic peripheral inner membrane proteome of the model organism Escherichia coli using a multidisciplinary approach. Initially, we extensively re-annotated the theoretical proteome regarding subcellular localization using literature searches, manual curation, and multi-combinatorial bioinformatics searches of the available databases. Next we used sequential biochemical fractionations coupled to direct identification of individual proteins and protein complexes using high resolution mass spectrometry. We determined that the proposed cytoplasmic peripheral inner membrane proteome occupies a previously unsuspected ?19% of the basic E. coli BL21(DE3) proteome, and the detected peripheral inner membrane proteome occupies ?25% of the estimated expressed proteome of this cell grown in LB medium to mid-log phase. This value might increase when fleeting interactions, not studied here, are taken into account. Several proteins previously regarded as exclusively cytoplasmic bind membranes avidly. Many of these proteins are organized in functional or/and structural oligomeric complexes that bind to the membrane with multiple interactions. Identified proteins cover the full spectrum of biological activities, and more than half of them are essential. Our data suggest that the cytoplasmic proteome displays remarkably dynamic and extensive communication with biological membrane surfaces that we are only beginning to decipher. PMID:23230279

Papanastasiou, Malvina; Orfanoudaki, Georgia; Koukaki, Marina; Kountourakis, Nikos; Sardis, Marios Frantzeskos; Aivaliotis, Michalis; Karamanou, Spyridoula; Economou, Anastassios

2013-03-01

227

Phylogenetic and genomic diversity of human bacteremic Escherichia coli strains  

Microsoft Academic Search

BACKGROUND: Extraintestinal pathogenic Escherichia coli (ExPEC) strains represent a huge public health burden. Knowledge of their clonal diversity and of the association of clones with genomic content and clinical features is a prerequisite to recognize strains with a high invasive potential. In order to provide an unbiased view of the diversity of E. coli strains responsible for bacteremia, we studied

Françoise Jaureguy; Luce Landraud; Virginie Passet; Laure Diancourt; Eric Frapy; Ghislaine Guigon; Etienne Carbonnelle; Olivier Lortholary; Olivier Clermont; Erick Denamur; Bertrand Picard; Xavier Nassif; Sylvain Brisse

2008-01-01

228

Escherichia coli Response to Exogenous Pyrophosphate and Analogs  

Microsoft Academic Search

The addition of exogenous pyrophosphate increases the growth yield and cAMP synthesis in stationary phase when Escherichia coli is grown in minimal medium. Pyrophosphate increases the yield by altering the enterobactin uptake system. We studied the physiological effects and examined how the E. coli transcriptome was modified when two structural analogs of pyrophosphate were added to the growth medium. Methylenediphosphonic

Francis Biville; Taku Oshima; Hirotada Mori; Yuya Kawagoe; Odile Bouvet; Marie-Noëlle Rager; Marina Perrotte-Piquemal; Antoine Danchin

2003-01-01

229

Genetic engineering of ethanol production in Escherichia coli  

Microsoft Academic Search

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

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

1987-01-01

230

Complete Genome Sequence of Escherichia coli BW25113.  

PubMed

Escherichia coli BW25113 is the parent strain of the Keio collection comprising nearly 4,000 single-gene deletion mutants. We report the complete 4,631,469-bp genome sequence of this strain and the key variations from the type strain E. coli MG1655. PMID:25323716

Grenier, Frédéric; Matteau, Dominick; Baby, Vincent; Rodrigue, Sébastien

2014-01-01

231

Transcriptional effects of CRP* expression in Escherichia coli  

Microsoft Academic Search

BACKGROUND: Escherichia coli exhibits diauxic growth in sugar mixtures due to CRP-mediated catabolite repression and inducer exclusion related to phosphotransferase system enzyme activity. Replacement of the native crp gene with a catabolite repression mutant (referred to as crp*) enables co-utilization of glucose and other sugars in E. coli. While previous studies have examined the effects of expressing CRP* mutants on

Reza Khankal; Jonathan W Chin; Debashis Ghosh; Patrick C Cirino

2009-01-01

232

Complete Genome Sequence of Escherichia coli BW25113  

PubMed Central

Escherichia coli BW25113 is the parent strain of the Keio collection comprising nearly 4,000 single-gene deletion mutants. We report the complete 4,631,469-bp genome sequence of this strain and the key variations from the type strain E. coli MG1655. PMID:25323716

Grenier, Frederic; Matteau, Dominick; Baby, Vincent

2014-01-01

233

Transformation of Escherichia coli by a specific DNA restriction fragment  

Microsoft Academic Search

Specific transformation of a rifampicin sensitive strain of Escherichia coli to rifampicin resistance has been performed by a single, defined DNA restriction fragment carrying the genetic information for the ß subunit of E. coli RNA polymerase. In this transformation the transforming genetic character has been substituted for the corresponding recipient gene locus by recombination. The value of the described transformation

Silvia M. Schweitzer; Hans Matzura

1977-01-01

234

Instability of repeated DNAs during transformation in Escherichia coli  

Microsoft Academic Search

Escherichia coli has provided an important model system for understanding the molecular basis for genetic instabilities associated with repeated DNA. Changes in triplet repeat length during growth following transformation in E. coli have been used as a measure of repeat instability. However, very little is known about the molecular and biological changes that may occur on transformation. Since only a

Vera I. Hashem; Elzbieta A. Klysik; William A. Rosche; Richard R. Sinden

2002-01-01

235

Motility and Chemotaxis of Filamentous Cells of Escherichia coli  

Microsoft Academic Search

Filamentous cells of Escherichia coli can be produced by treatment with the antibiotic cephalexin, which blocks cell division but allows cell growth. To explore the effect of cell size on chemotactic activity, we studied the motility and chemotaxis of filamentous cells. The filaments, up to 50 times the length of normal E. coli organisms, were motile and had flagella along

NAZLI MAKI; JASON E. GESTWICKI; ELLEN M. LAKE; LAURA L. KIESSLING; J. Adler

2000-01-01

236

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. PMID:23819107

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

2013-01-01

237

Shiga toxin-producing Escherichia coli  

PubMed Central

Shiga toxin-producing Escherichia coli (STEC) cause hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS) in humans. Outbreaks are linked to bovine food sources. STEC O157:H7 has been responsible for the most severe outbreaks worldwide. However, non-O157 serotypes have emerged as important enteric pathogens in several countries. The main virulence factor of STEC is the production of Shiga toxins 1 and 2. Additional virulence markers are a plasmid-encoded enterohemolysin (ehxA), an autoagglutinating adhesin (Saa), a catalase-peroxidase (katP), an extracellular serine protease (espP), a zinc metalloprotease (stcE), a subtilase cytotoxin (subAB), among others. Other virulence factors are intimin and adhesins that had a roll in the adherence of STEC to bovine colon. This review focuses on the virulence traits of STEC and especially on those related to the adhesion to bovine colon. The known of the interaction between STEC and the bovine host is crucial to develop strategies to control cattle colonization. PMID:23624795

Etcheverria, Analia Ines; Padola, Nora Lia

2013-01-01

238

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

239

The DNA exonucleases of Escherichia coli  

PubMed Central

DNA exonucleases, enzymes that hydrolyze phosphodiester bonds in DNA from a free end, play important cellular roles in DNA repair, genetic recombination and mutation avoidance in all organisms. This article reviews the structure, biochemistry and biological functions of the 17 exonucleases currently identified in the bacterium Escherichia coli. These include the exonucleases associated with DNA polymerases I (polA), II (polB) and III (dnaQ/mutD), Exonucleases I (xonA/sbcB), III (xthA), IV, VII (xseAB), IX (xni/xgdG) and X (exoX), the RecBCD, RecJ, and RecE exonucleases, SbcCD endo/exonuclease, the DNA exonuclease activities of RNase T (rnt) and Endonuclease IV (nfo) and TatD. These enzymes are diverse in terms of substrate specificity and biochemical properties and have specialized biological roles. Most of these enzymes fall into structural families with characteristic sequence motifs, and members of many of these families can be found in all domains of life.

Lovett, Susan T.

2014-01-01

240

Regulation of the Escherichia coli lrp gene.  

PubMed Central

Lrp (leucine-responsive regulatory protein) is a major Escherichia coli regulatory protein which regulates expression of a number of operons, some negatively and some positively. This work relates to a characterization of lrp, the gene encoding Lrp. Nucleotide sequencing established that the coding regions of lrp and trxB (encoding thioredoxin reductase) are separated by 543 bp and that the two genes are transcribed in opposite directions. In addition, we used primer extension, deletion analyses, and lrp-lacZ transcriptional fusions to delineate the promoter and regulatory region of the lrp operon. The lrp promoter is located 267 nucleotides upstream of the translational start codon of the lrp gene. In comparison with a wild-type strain, expression of the lrp operon was increased about 3-fold in a strain lacking Lrp and decreased about 10-fold in a strain overproducing Lrp. As observed from DNA mobility shift and DNase I footprinting analyses, Lrp binds to one or more sites within the region -80 to -32 relative to the start point of lrp transcription. A mutational analysis indicated that this same region is at least partly required for repression of lrp expression in vivo. These results demonstrate that autogenous regulation of lrp involves Lrp acting directly to cause repression of lrp transcription. Images PMID:8144448

Wang, Q; Wu, J; Friedberg, D; Plakto, J; Calvo, J M

1994-01-01

241

Type 1 fimbriae contribute to catheter-associated urinary tract infections caused by Escherichia coli.  

PubMed

Biofilm formation on catheters is thought to contribute to persistence of catheter-associated urinary tract infections (CAUTI), which represent the most frequent nosocomial infections. Knowledge of genetic factors for catheter colonization is limited, since their role has not been assessed using physicochemical conditions prevailing in a catheterized human bladder. The current study aimed to combine data from a dynamic catheterized bladder model in vitro with in vivo expression analysis for understanding molecular factors relevant for CAUTI caused by Escherichia coli. By application of the in vitro model that mirrors the physicochemical environment during human infection, we found that an E. coli K-12 mutant defective in type 1 fimbriae, but not isogenic mutants lacking flagella or antigen 43, was outcompeted by the wild-type strain during prolonged catheter colonization. The importance of type 1 fimbriae for catheter colonization was verified using a fimA mutant of uropathogenic E. coli strain CFT073 with human and artificial urine. Orientation of the invertible element (IE) controlling type 1 fimbrial expression in bacterial populations harvested from the colonized catheterized bladder in vitro suggested that the vast majority of catheter-colonizing cells (up to 88%) express type 1 fimbriae. Analysis of IE orientation in E. coli populations harvested from patient catheters revealed that a median level of ?73% of cells from nine samples have switched on type 1 fimbrial expression. This study supports the utility of the dynamic catheterized bladder model for analyzing catheter colonization factors and highlights a role for type 1 fimbriae during CAUTI. PMID:24336940

Reisner, Andreas; Maierl, Mario; Jörger, Michael; Krause, Robert; Berger, Daniela; Haid, Andrea; Tesic, Dijana; Zechner, Ellen L

2014-03-01

242

Type 1 Fimbriae Contribute to Catheter-Associated Urinary Tract Infections Caused by Escherichia coli  

PubMed Central

Biofilm formation on catheters is thought to contribute to persistence of catheter-associated urinary tract infections (CAUTI), which represent the most frequent nosocomial infections. Knowledge of genetic factors for catheter colonization is limited, since their role has not been assessed using physicochemical conditions prevailing in a catheterized human bladder. The current study aimed to combine data from a dynamic catheterized bladder model in vitro with in vivo expression analysis for understanding molecular factors relevant for CAUTI caused by Escherichia coli. By application of the in vitro model that mirrors the physicochemical environment during human infection, we found that an E. coli K-12 mutant defective in type 1 fimbriae, but not isogenic mutants lacking flagella or antigen 43, was outcompeted by the wild-type strain during prolonged catheter colonization. The importance of type 1 fimbriae for catheter colonization was verified using a fimA mutant of uropathogenic E. coli strain CFT073 with human and artificial urine. Orientation of the invertible element (IE) controlling type 1 fimbrial expression in bacterial populations harvested from the colonized catheterized bladder in vitro suggested that the vast majority of catheter-colonizing cells (up to 88%) express type 1 fimbriae. Analysis of IE orientation in E. coli populations harvested from patient catheters revealed that a median level of ?73% of cells from nine samples have switched on type 1 fimbrial expression. This study supports the utility of the dynamic catheterized bladder model for analyzing catheter colonization factors and highlights a role for type 1 fimbriae during CAUTI. PMID:24336940

Maierl, Mario; Jorger, Michael; Krause, Robert; Berger, Daniela; Haid, Andrea; Tesic, Dijana; Zechner, Ellen L.

2014-01-01

243

EcoCyc: A comprehensive view of Escherichia coli biology  

Microsoft Academic Search

EcoCyc (http:\\/\\/EcoCyc.org) provides a comprehen- sive encyclopedia of Escherichia coli biology. EcoCyc integrates information about the genome, genes and gene products; the metabolic network; and the regulatory network of E. coli. Recent EcoCyc developments include a new initiative to represent and curate all types of E. coli regulatory processes such as attenuation and regulation by small RNAs. EcoCyc has started

Ingrid M. Keseler; César Bonavides-martínez; Julio Collado-vides; Socorro Gama-castro; Robert P. Gunsalus; D. Aaron Johnson; Markus Krummenacker; Laura M. Nolan; Suzanne M. Paley; Ian T. Paulsen; Martín Peralta-gil; Alberto D. Santos-zavaleta; Alexander Glennon Shearer; Peter D. Karp

2009-01-01

244

Detection of Escherichia coli in wastewater based on enzyme immunoassay  

Microsoft Academic Search

This research describes a fast detection method on the basis of enzyme-linked immunosorbent assay (ELISA) for Escherichia coli in drainage of wastewater treatment plants. Optimized conditions such as the reaction format (sandwich or direct), the concentrations\\u000a of diluted horseradish peroxidase (HRP)-E. coli conjugate, and anti-HPR antibody and pretreatment of E. coli were studied. Those results showed that the linear range

Haiyan Xi; Qiang Cai; Miao He; Hanchang Shi

2007-01-01

245

Functional Homology of Chemotaxis Genes Escherichia coli and Salmonella typhimurium  

Microsoft Academic Search

Generally nonchemotactic mutants of Escherichia coli and Salmonella typhi- murium were analyzed by interspecies complementation tests to determine the functional correspondence between the che genes of these two organisms. The E. coli che region was introduced into Salnonella recipients by means of a series of F-prime elements. Wild-type che genes of E. coli F'420 complemented all che mutants of Sabnonella

Anthony L. Defranco; JOHN S. PARKINSON; D. E. KOSHLAND

1979-01-01

246

Involvement of Escherichia coli DNA polymerase IV in tolerance of cytotoxic alkylating DNA lesions in vivo  

E-print Network

1 Involvement of Escherichia coli DNA polymerase IV in tolerance of cytotoxic alkylating DNA coli DNA polymerase IV Key words: Escherichia coli, dinB, alkylation damage, DNA repair Corresponding Escherichia coli PolIV, a DNA polymerase capable to catalyze synthesis past replication- blocking DNA lesions

247

Evolution of transcription factors and the gene regulatory network in Escherichia coli  

E-print Network

Evolution of transcription factors and the gene regulatory network in Escherichia coli M. Madan Escherichia coli. In order to gain insight into the evolution of the E.coli regula- tory network, we analysed-dimensional structures. Theoretical analyses of transcription factors in Escherichia coli have focused on their sequence

Babu, M. Madan

248

Enteropathogenic Escherichia coli translocated intimin receptor, Tir, requires a specic chaperone for stable  

E-print Network

Enteropathogenic Escherichia coli translocated intimin receptor, Tir, requires a speci®c chaperone. Summary Enteropathogenic Escherichia coli (EPEC) secretes several Esps (E. coli-secreted proteins Enteropathogenic Escherichia coli (EPEC) is a major cause of diarrhoea in young children (Donnenberg and Kaper

Strynadka, Natalie

249

????????????? ?????? ???????? ???????????? ?-?????????? SHV-????? ?? ??????? ??????? ??? ????? Klebsiella pneumoniae, Escherichia coli ??? Serratia marcescens.: [???] ???????? ?. ?????????.  

E-print Network

?????????????? ? ?????????? ??? ????????? ????????????? ??? ???? ???????????? ?-?????????? SHV-?????.? SHV-9 ?-????????? ??????????? ??? ??????? ??????? ?.PNEUMONIAE,E.COLI KAI S.MARCESCENS.ME ????? ???????? ????????? ???????.?? ?????… (more)

??????????, ????????

1997-01-01

250

Receptor binding studies disclose a novel class of high-affinity inhibitors of the Escherichia coli FimH adhesin.  

PubMed

Mannose-binding type 1 pili are important virulence factors for the establishment of Escherichia coli urinary tract infections (UTIs). These infections are initiated by adhesion of uropathogenic E. coli to uroplakin receptors in the uroepithelium via the FimH adhesin located at the tips of type 1 pili. Blocking of bacterial adhesion is able to prevent infection. Here, we provide for the first time binding data of the molecular events underlying type 1 fimbrial adherence, by crystallographic analyses of the FimH receptor binding domains from a uropathogenic and a K-12 strain, and affinity measurements with mannose, common mono- and disaccharides, and a series of alkyl and aryl mannosides. Our results illustrate that the lectin domain of the FimH adhesin is a stable and functional entity and that an exogenous butyl alpha-D-mannoside, bound in the crystal structures, exhibits a significantly better affinity for FimH (Kd = 0.15 microM) than mannose (Kd = 2.3 microM). Exploration of the binding affinities of alpha- d-mannosides with longer alkyl tails revealed affinities up to 5 nM. Aryl mannosides and fructose can also bind with high affinities to the FimH lectin domain, with a 100-fold improvement and 15-fold reduction in affinity, respectively, compared with mannose. Taken together, these relative FimH affinities correlate exceptionally well with the relative concentrations of the same glycans needed for the inhibition of adherence of type 1 piliated E. coli. We foresee that our findings will spark new ideas and initiatives for the development of UTI vaccines and anti-adhesive drugs to prevent anticipated and recurrent UTIs. PMID:15659162

Bouckaert, Julie; Berglund, Jenny; Schembri, Mark; De Genst, Erwin; Cools, Lieve; Wuhrer, Manfred; Hung, Chia-Suei; Pinkner, Jerome; Slättegård, Rikard; Zavialov, Anton; Choudhury, Devapriya; Langermann, Solomon; Hultgren, Scott J; Wyns, Lode; Klemm, Per; Oscarson, Stefan; Knight, Stefan D; De Greve, Henri

2005-01-01

251

Tobramycin uptake in Escherichia coli membrane vesicles.  

PubMed Central

The uptake of tobramycin was measured in Escherichia coli membrane vesicles prepared in KMES [K(+)-2-(N-morpholino)ethanesulfonic acid] buffer at pH 6.6. Uptake occurred in vesicles energized with ascorbic acid and phenazine methosulfate, in which the electrical potential (delta psi) was -120 mV, but not in vesicles energized with D-lactate (delta psi = -95 mV). The addition of nigericin to vesicles energized with D-lactate did not induce tobramycin uptake despite an increase in delta psi to -110 mV. However, when delta psi was increased or decreased by the addition of nigericin or valinomycin, respectively, uptake in vesicles energized with ascorbic acid and phenazine methosulfate was stimulated or inhibited, respectively, confirming studies with whole cells showing that uptake of aminoglycosides is gated by delta psi rather than by proton motive force (delta microH+) or delta pH. N-ethylmaleimide prevented uptake, suggesting that the aminoglycoside transporter is a cytoplasmic membrane protein with accessible sulfhydryl groups. The observation that uptake is gated in vesicles as well as in whole cells suggested that diffusion occurs through a voltage-gated channel. In vesicles preloaded with tobramycin, no efflux occurred after the addition of the protonophore carbonyl cyanide m-chlorophenylhydrazone. In susceptible cells, aminoglycosides themselves decreased the magnitude of delta psi. We propose a mechanism of aminoglycoside-induced killing in which aminoglycosides themselves close the voltage-gated channel by decreasing the magnitude of delta psi. Channel closure causes aminoglycosides accumulated prior to the fall in delta psi to be trapped, which in turn causes irreversible uptake and subsequent bactericidal effects. PMID:7726517

Leviton, I M; Fraimow, H S; Carrasco, N; Dougherty, T J; Miller, M H

1995-01-01

252

Tamm-Horsfall protein binds to type 1 fimbriated Escherichia coli and prevents E. coli from binding to uroplakin Ia and Ib receptors.  

PubMed

The adherence of uropathogenic Escherichia coli to the urothelial surface, a critical first step in the pathogenesis of urinary tract infection (UTI), is controlled by three key elements: E. coli adhesins, host receptors, and host defense mechanisms. Although much has been learned about E. coli adhesins and their urothelial receptors, little is known about the role of host defense in the adherence process. Here we show that Tamm-Horsfall protein (THP) is the principal urinary protein that binds specifically to type 1 fimbriated E. coli, the main cause of UTI. The binding was highly specific and saturable and could be inhibited by d-mannose and abolished by endoglycosidase H treatment of THP, suggesting that the binding is mediated by the high-mannose moieties of THP. It is species-conserved, occurring in both human and mouse THPs. In addition, the binding to THP was much greater with an E. coli strain bearing a phenotypic variant of the type 1 fimbrial FimH adhesin characteristic of those prevalent in UTI isolates compared with the one prevalent in isolates from the large intestine of healthy individuals. Finally, a physiological concentration of THP completely abolished the binding of type 1 fimbriated E. coli to uroplakins Ia and Ib, two putative urothelial receptors for type 1 fimbriae. These results establish, on a functional level, that THP contains conserved high-mannose moieties capable of specific interaction with type 1 fimbriae and strongly suggest that this major urinary glycoprotein is a key urinary anti-adherence factor serving to prevent type 1 fimbriated E. coli from binding to the urothelial receptors. PMID:11134021

Pak, J; Pu, Y; Zhang, Z T; Hasty, D L; Wu, X R

2001-03-30

253

Serological cross-reactions between Escherichia coli O157 and other species of the genus Escherichia.  

PubMed

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 polyclonal antisera and in the slide agglutination assay by using latex reagents. Only four isolates (17%) of E. hermannii exhibited serological cross-reactivity. PMID:1583138

Rice, E W; Sowers, E G; Johnson, C H; Dunnigan, M E; Strockbine, N A; Edberg, S C

1992-05-01

254

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. PMID:22104113

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

2012-01-01

255

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

PubMed

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 of type 1 pili, which are required for pathogenesis during urinary tract infection. Notably, the curlicides retained pilicide activities and inhibited both curli-dependent and type 1-dependent biofilms. Furthermore, pretreatment of UPEC with FN075 significantly attenuated virulence in a mouse model of urinary tract infection. Curli and type 1 pili exhibited exclusive and independent roles in promoting UPEC biofilms, and curli provided a fitness advantage in vivo. Thus, the ability of FN075 to block the biogenesis of both curli and type 1 pili endows unique anti-biofilm and anti-virulence activities on these compounds. PMID:19915538

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

2009-12-01

256

A sticky chain model of the elongation and unfolding of Escherichia coli P pili under stress.  

PubMed

A model of the elongation of P pili expressed by uropathogenic Escherichia coli exposed to stress is presented. The model is based upon the sticky chain concept, which is based upon Hooke's law for elongation of the layer-to-layer and head-to-tail bonds between neighboring units in the PapA rod and a kinetic description of the opening and closing of bonds, described by rate equations and an energy landscape model. It provides an accurate description of the elongation behavior of P pili under stress and supports a hypothesis that the PapA rod shows all three basic stereotypes of elongation/unfolding: elongation of bonds in parallel, the zipper mode of unfolding, and elongation and unfolding of bonds in series. The two first elongation regions are dominated by a cooperative bond opening, in which each bond is influenced by its neighbor, whereas the third region can be described by individual bond opening, in which the bonds open and close randomly. A methodology for a swift extraction of model parameters from force-versus-elongation measurements performed under equilibrium conditions is derived. Entities such as the free energy, the stiffness, the elastic elongation, the opening length of the various bonds, and the number of PapA units in the rod are determined. PMID:16361334

Andersson, Magnus; Fällman, Erik; Uhlin, Bernt Eric; Axner, Ove

2006-03-01

257

Evolution of Escherichia coli rifampicin resistance in an antibiotic-free environment during thermal stress  

E-print Network

antibiotic resistance and the population genetics of adaptive evolutionEvolution of Escherichia coli rifampicin resistance in an antibiotic-Evolution of Escherichia coli rifampicin resistance in an antibiotic-

Rodríguez-Verdugo, Alejandra; Gaut, Brandon S; Tenaillon, Olivier

2013-01-01

258

The Evolution and Structural Anatomy of the Small Molecule Metabolic Pathways in Escherichia coli  

E-print Network

The Evolution and Structural Anatomy of the Small Molecule Metabolic Pathways in Escherichia coli The 106 small molecule metabolic (SMM) pathways in Escherichia coli are formed by the protein products

Gough, Julian

259

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 PMID:2644022

Karmali, M A

1989-01-01

260

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. PMID:20682870

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

2010-01-01

261

Sepsis caused by food-borne infection with Escherichia coli.  

PubMed

We report a case of sepsis caused by Escherichia coli (E. coli) of serotype O-143. A 78-year-old man developed symptoms of gastroenteritis after ingesting raw meat on noodles. He rapidly developed respiratory failure. Blood culture grew E. coli. The sepsis seemed to have directly spread from a food-borne infection. The development of primary sepsis after ingesting E. coli is very rare. We suspect that bacterial translocation played a major role. Serotype O-143 is recognized in enteroinvasive E. coli (EIEC) as well as in Shigella dysenteriae. The pathogen in the present case is suspected of being EIEC although the isolated E. coli strain was negative for the inv and ipa genes. PMID:16415557

Wachi, Keiko; Tateda, Kazuhiro; Yamashiro, Yoshihiro; Takahashi, Miki; Matsumoto, Tetsuya; Furuya, Nobuhiko; Ishii, Yoshikazu; Akasaka, Yoshikiyo; Yamaguchi, Keizo; Uchida, Kou

2005-12-01

262

Cattle Water Troughs as Reservoirs of Escherichia coli O157  

PubMed Central

Environmental survival of Escherichia coli O157 may play an important role in the persistence and dissemination of this organism on farms. The survival of culturable and infectious E. coli O157 was studied using microcosms simulating cattle water troughs. Culturable E. coli O157 survived for at least 245 days in the microcosm sediments. Furthermore, E. coli O157 strains surviving more than 6 months in contaminated microcosms were infectious to a group of 10-week-old calves. Fecal excretion of E. coli O157 by these calves persisted for 87 days after challenge. Water trough sediments contaminated with feces from cattle excreting E. coli O157 may serve as a long-term reservoir of this organism on farms and a source of infection for cattle. PMID:11425721

LeJeune, Jeffrey T.; Besser, Thomas E.; Hancock, Dale D.

2001-01-01

263

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

264

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

265

Overproduction and purification of Lon protease from Escherichia coli  

Microsoft Academic Search

Lon protease, which plays a major role in degradation of abnormal proteins in Escherichia coli,was overproduced and efficiently purified using the maltose-binding protein (MBP) fusion vector. The MBP-Lon fusion protein was expressed in a soluble form in E. coli and purified to homogeneity by amylose resin in a single step. Lon protease was split from MBP by cleaving a fusion

S. Sonezaki; A. Kondo; T. Oba; Y. Ishii; Y. Kato; H. Nakayama

1994-01-01

266

Escherichia coli growth and plasmid copy numbers in continuous cultivations  

Microsoft Academic Search

Summary AnEscherichia coli K-12 strain harbouring either the plasmid pBR322, or the recombinant plasmid pKTH1220, a 14 kb derivative of pBR322, or no plasmid was grown in a chemostat. The cultivations were continued for 300–400 bacterial generations.E. coli hosts harbouring pBR322 or no plasmid grew in a similar way, but the growth of the host containing the big recombinant plasmid

P. Reinikainen; I. Virkajärvi

1989-01-01

267

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

268

Deactivation of Escherichia coli by the plasma needle  

Microsoft Academic Search

In this paper we present a parameter study on deactivation of Escherichia coli (E. coli) by means of a non-thermal plasma (plasma needle). The plasma needle is a small-sized (1 mm) atmospheric glow sustained by radio-frequency excitation. This plasma will be used to disinfect heat-sensitive objects; one of the intended applications is in vivo deactivation of dental bacteria: destruction of

R. E. J. Sladek; E. Stoffels

2005-01-01

269

Data processing by the chemotaxis machinery of Escherichia coli  

Microsoft Academic Search

THE chemotactic behaviour of Escherichia coli provides a useful model for study of the molecular basis of a simple stimulus-response sequence1. Chemical stimuli are detected by specific receptors2 which in turn alter the rotation of the flagella3 to elicit movement towards attractants or away from repellents. About twenty types of chemoreceptors have been identified in E. coli4-6, suggesting that a

John S. Parkinson

1974-01-01

270

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

271

ORIGINAL ARTICLE Identification of stress-related proteins in Escherichia coli  

E-print Network

ORIGINAL ARTICLE Identification of stress-related proteins in Escherichia coli using the pollutant observed in Escherichia coli; for example, a rapid shift from low to high temperatures induces biofilm formation has also been demonstrated Keywords cis-dichloroethylene, Escherichia coli, hydrogen

Wood, Thomas K.

272

Selection Footprint in the FimH Adhesin Shows Pathoadaptive Niche Differentiation in Escherichia coli  

E-print Network

-adaptive, or pathoadaptive, mutations in the Escherichia coli gene encoding FimH--the major, mannose-sensitive adhesin protein of Escherichia coli, mutations in which are pathoadaptive for uropatho- genic E. coli clonesSelection Footprint in the FimH Adhesin Shows Pathoadaptive Niche Differentiation in Escherichia

Chattopadhyay, Sujay

273

Metabolism and evolution of Haemophilus influenzae deduced from a whole-genome comparison with Escherichia coli  

E-print Network

with Escherichia coli Roman L.Tatusov*§, Arcady R. Mushegian*§, Peer Bork, Nigel P. Brown, William S. Hayes, Mark recently reported. Approximately 75 % of the 4.7 Mb genome sequence of Escherichia coli is also available by Fleischmann et al. [1]. Approximately 75 % of the 4.7 Mb genome sequence of Escherichia coli is also available

Fernando, Chrisantha

274

Finite state abstraction of a stochastic model of the lactose regulation system of Escherichia coli  

E-print Network

Finite state abstraction of a stochastic model of the lactose regulation system of Escherichia coli on the lactose regulation system in Escherichia coli bacteria, one of the most extensively studied examples for the lactose regulation system in the Escherichia coli bacteria. The lactose operon [8] is one of the most

Sontag, Eduardo

275

Proteome analysis of factor for inversion stimulation (Fis) overproduction in Escherichia coli  

E-print Network

Proteome analysis of factor for inversion stimulation (Fis) overproduction in Escherichia coli The factor-for-inversion stimulation protein (Fis) is a global regulatory protein in Escherichia coli protein precursor, and ketol-acid reductoisomerase. Keywords: Proteome analysis / Fis / Escherichia coli

Chen, Wilfred

276

SLECTION ET PERSISTANCE, DANS LA FLORE FCALE DE VEAUX DE BOUCHERIE, DE ESCHERICHIA COLI  

E-print Network

S�LECTION ET PERSISTANCE, DANS LA FLORE F�CALE DE VEAUX DE BOUCHERIE, DE ESCHERICHIA COLI R�SISTANT of oxytetracycline on the resistance of fecal Escherichia coli to the following antibacterial agents: ampicillin (Ap flore fécale, de souches d'Escherichia coli résistantes à cet antibiotique (Mitsuhashi, 1979). Ces sou

Paris-Sud XI, Université de

277

Chemosensing in Escherichia coli: Two regimes of two-state receptors  

E-print Network

Chemosensing in Escherichia coli: Two regimes of two-state receptors Juan E. Keymer* , Robert G, 2005 (received for review August 26, 2005) The chemotaxis network in Escherichia coli is remarkable The chemotaxis network in Escherichia coli is the best studied signal-transduction network of any living organism

Meir, Yigal

278

Dynamic Receptor Team Formation Can Explain the High Signal Transduction Gain in Escherichia coli  

E-print Network

Dynamic Receptor Team Formation Can Explain the High Signal Transduction Gain in Escherichia coli in the peritrichous bacterium Escherichia coli, which has four helical flagella distributed over the cell surface explain this observation. INTRODUCTION Escherichia coli has five receptor types, but most is known about

Othmer, Hans

279

Escherichia coli: a brief review of diarrheagenic pathotypes and their role in diarrheal diseases in Iran  

E-print Network

Escherichia coli: a brief review of diarrheagenic pathotypes and their role in diarrheal diseases, Tehran. 2 Bacteriology Department, Pasteur Institute of Iran, Tehran. 3 National Escherichia coli, Aslani MM Address: Molecular Biology Unit, Pasteur Institute of Iran. National Escherichia coli Reference

Paris-Sud XI, Université de

280

Uncharacterized Escherichia coli proteins YdjA and YhjY are related to biohydrogen production  

E-print Network

Uncharacterized Escherichia coli proteins YdjA and YhjY are related to biohydrogen production Mohd: Biohydrogen Escherichia coli ydjA yhjY FHL inactivation a b s t r a c t Biohydrogen has gained importance and efficiency of biohydrogen production from various microorganisms and substrates. Here, Escherichia coli

Wood, Thomas K.

281

Brief Original Article Multiple contaminations of chickens with Campylobacter, Escherichia coli  

E-print Network

Brief Original Article Multiple contaminations of chickens with Campylobacter, Escherichia coli, Escherichia coli, and Salmonella are mainly caused by the consumption of raw or undercooked poultry meat. The objective of this study was to evaluate the prevalence of Campylobacter, Escherichia coli, and Salmonella

Paris-Sud XI, Université de

282

RELATEDNESS OF ESCHERICHIA COLI WITH DIFFERENT SUSCEPTIBILITY1 PHENOTYPES ISOLATED FROM SWINE FECES DURING AMPICILLIN2  

E-print Network

1 RELATEDNESS OF ESCHERICHIA COLI WITH DIFFERENT SUSCEPTIBILITY1 PHENOTYPES ISOLATED FROM SWINE. Bousquet-Mélou1* 5 6 Running title: Relatedness of fecal Escherichia coli isolates7 8 UMR181 Escherichia coli populations during treatment with ampicillin for 7 days in pigs. Before23 treatment, only 6

Boyer, Edmond

283

Finite state abstraction of a stochastic model of the lactose regulation system of Escherichia coli  

E-print Network

Finite state abstraction of a stochastic model of the lactose regulation system of Escherichia coli on the lactose regulation system in Escherichia coli bacteria, one of the most extensively studied examples hybrid model for the lactose regulation system in the Escherichia coli bacteria. The lactose operon [10

Pappas, George J.

284

Division accuracy in a stochastic model of Min oscillations in Escherichia coli  

E-print Network

Division accuracy in a stochastic model of Min oscillations in Escherichia coli Rex A. Kerr in Escherichia coli requires the Min proteins MinC, MinD, and MinE as well as the presence of nucleoids. Min, to explain wild-type accuracy. dynamics MCELL FtsZ The rod-shaped bacterium Escherichia coli reproduces

Watkins, Joseph C.

285

Unstable Escherichia coli L-forms revisited:4 growth requires peptidoglycan synthesis5  

E-print Network

1 1 2 3 Unstable Escherichia coli L-forms revisited:4 growth requires peptidoglycan synthesis5 of a wild type Escherichia coli K-12 strain overnight to a growing5 L-form-like state, using the -lactam L-forms require, using Escherichia coli K-12 as model.8 Septal synthesis is carried out

Paris-Sud XI, Université de

286

Escherichia coli heat-stable enterotoxin b (STb) in vivo internalization within rat intestinal epithelial cells  

E-print Network

Short note Escherichia coli heat-stable enterotoxin b (STb) in vivo internalization within rat distributed within the cell. Escherichia coli / STb enterotoxin / internalization Résumé ­ Internalisation in vivo de l'entérotoxine b (STb) d'Escherichia coli dans les cellules épithéliales d'intestin de rat. L

Boyer, Edmond

287

An Experimental and Theoretical Study of the Inhibition of Escherichia coli lac  

E-print Network

An Experimental and Theoretical Study of the Inhibition of Escherichia coli lac Operon Gene the inhibition of Escherichia coli lac operon gene expression by anti- gene oligos. Our model predicted 74: 220­229, 2001. Keywords: Escherichia coli lac operon; antigene oligo- nucleotide; triplex

Relue, Patricia

288

Effects of Discontinuities in the DNA Template on Abortive Initiation and Promoter Escape by Escherichia coli  

E-print Network

by Escherichia coli RNA Polymerase* Received for publication,March 22, 2007, and in revised form, July 20, 2007 related to the process of transcription initiation by Escherichia coli RNA polymerase, confirming transcribing complexes (ITCs)2 of Escherichia coli RNA polymerase bearing 5­8-nt transcripts revealed

Tullius, Thomas D.

289

Cross-reaction of chalcone synthase and stilbene synthase overexpressed in Escherichia coli  

E-print Network

Cross-reaction of chalcone synthase and stilbene synthase overexpressed in Escherichia coli Toshio STS overexpressed in Escherichia coli, bisnoryangonin (BNY, the derailed lactone after two that was overexpressed in Escherichia coli, we have detected bisnoryangonin (BNY, the derailed lactone after two

Suh, Dae-Yeon

290

Author's personal copy Improving cellular malonyl-CoA level in Escherichia coli  

E-print Network

Author's personal copy Improving cellular malonyl-CoA level in Escherichia coli via metabolic a b s t r a c t Escherichia coli only maintains a small amount of cellular malonyl-CoA, impeding its, Escherichia coli has become an attractive host for natural product manufac- ture, owing to its genetic

Zhao, Huimin

291

Review article Escherichia coli as a pathogen in dogs and cats  

E-print Network

Review article Escherichia coli as a pathogen in dogs and cats Lothar Beutin Robert Koch; accepted 17December 1998) Abstraet-Certain strains of Escherichia coli behave as pathogens in dogs and cats. © Inra/Elsevier, Paris. Escherichia coli infections / dogs / cats / humans / diarrhoea / extra

Paris-Sud XI, Université de

292

Motility of Escherichia coli cells in clusters formed by chemotactic aggregation  

E-print Network

Motility of Escherichia coli cells in clusters formed by chemotactic aggregation Nikhil Mittal of Escherichia coli under conditions of certain cellular stresses excrete attractants. Cells of chemotactic Escherichia coli and Salmonella spp., have been studied in great detail (1­3). For our purposes, the following

van Oudenaarden, Alexander

293

DNA modication and functional delivery into human cells using Escherichia coli DH10B  

E-print Network

DNA modi®cation and functional delivery into human cells using Escherichia coli DH10B Kumaran report a novel comprehen- sive Escherichia coli-based vector system for the modi®cation, propagation in recombination- de®cient Escherichia coli DH10B imparts greater stability to the large BAC clones but has made

Warburton, Peter E.

294

Reprogramming of Escherichia coli K-12 Metabolism during the Initial Phase of Transition from an Anaerobic  

E-print Network

Reprogramming of Escherichia coli K-12 Metabolism during the Initial Phase of Transition from anaerobe Escherichia coli K-12 provides an ideal system for exploring this process. Methods and Findings) Reprogramming of Escherichia coli K-12 Metabolism during the Initial Phase of Transition from an Anaerobic

Williamson, Mike P.

295

Prevalence of Escherichia coli O157:H7 and Salmonella spp. in surface waters of southern  

E-print Network

Prevalence of Escherichia coli O157:H7 and Salmonella spp. in surface waters of southern Alberta. To address these concerns, we conducted a 2-year study to estimate the prevalence of Escherichia coli O157:H7 afin d'évaluer la prévalence de Escherichia coli O157:H7 et de Salmonella spp. dans les eaux de surface

Selinger, Brent

296

In vivo Dissection of the Tat Translocation Pathway in Escherichia coli  

E-print Network

-ColV. The translocation of RR-ColV fully inhibited the growth of wild-type Escherichia coli and those of the Átat for bacteria only under certain growth conditions. Escherichia coli Tat components are encoded by the tatIn vivo Dissection of the Tat Translocation Pathway in Escherichia coli Be�rengeÁre Ize1 , Fabien

Palmer, Tracy

297

Quantitative Profile of the Uropathogenic Escherichia coli Outer Membrane Proteome during Growth in Human Urine  

Microsoft Academic Search

Outer membrane proteins (OMPs) of microbial pathogens are critical components that mediate direct interactions between microbes and their surrounding environment. Consequently, the study of OMPs is integral to furthering the understanding of host-pathogen interactions and to identifying key targets for development of improved antimicrobial agents and vaccines. In this study, we used two-dimensional poly- acrylamide gel electrophoresis (2D-PAGE) and tandem

Christopher J. Alteri; Harry L. T. Mobley

2007-01-01

298

Intrauterine Growth Restriction Is a Direct Consequence of Localized Maternal Uropathogenic Escherichia coli Cystitis  

PubMed Central

Despite the continually increasing rates of adverse perinatal outcomes across the globe, the molecular mechanisms that underlie adverse perinatal outcomes are not completely understood. Clinical studies report that 10% of pregnant women will experience a urinary tract infection (UTI) and there is an association of UTIs with adverse perinatal outcomes. We introduced bacterial cystitis into successfully outbred female mice at gestational day 14 to follow pregnancy outcomes and immunological responses to determine the mechanisms that underlie UTI-mediated adverse outcomes. Outbred fetuses from mothers experiencing localized cystitis displayed intrauterine growth restriction (20–80%) as early as 48 hours post-infection and throughout the remainder of normal gestation. Robust infiltration of cellular innate immune effectors was observed in the uteroplacental tissue following introduction of UTI despite absence of viable bacteria. The magnitude of serum proinflammatory cytokines is elevated in the maternal serum during UTI. This study demonstrates that a localized infection can dramatically impact the immunological status as well as the function of non-infected distal organs and tissues. This model can be used as a platform to determine the mechanism(s) by which proinflammatory changes occur between non-contiguous genitourinary organs PMID:22470490

Bolton, Michael; Horvath, Dennis J.; Li, Birong; Cortado, Hanna; Newsom, David; White, Peter; Partida-Sanchez, Santiago; Justice, Sheryl S.

2012-01-01

299

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. PMID:24839441

Darfarin, Gita

2014-01-01

300

Bioaccumulation of Arsenic in recombinant Escherichia coli expressing human metallothionein  

Microsoft Academic Search

The recombinant Escherichia coli (E. coli) expressing human hepatic metallothionein_IA (hMT_IA) was constructed for bioaccumulation of Arsenic (As). The gene sequence\\u000a of hMT_IA was modified for codon preference of E. coli and synthesized using chemical method. The vector of pGEX_4T_1 was used and hMT_IA was expressed as the fusion protein with\\u000a glutathione S-transferase (GST) tag. The bioaccumulation capability of arsenite

Yu-Jie Su; Jian-Qun Lin; Jian-Qiang Lin; Dong-Hui Hao

2009-01-01

301

Analyzing the Escherichia coli Gene Expression Data by a Multilayer Adjusted Tree Organizing Map  

E-print Network

1 Analyzing the Escherichia coli Gene Expression Data by a Multilayer Adjusted Tree Organizing Map on biological data, none of them has examined the Escherichia coli (E. coli) gene expression data. This paper. coli gene expression data. In a semi-supervised manner, MATOM constructs a multilayer map

Gruenwald, Le

302

Escherichia coli producing CNF1 and CNF2 cytotoxins in animals with different disorders  

E-print Network

Short note Escherichia coli producing CNF1 and CNF2 cytotoxins in animals with different disorders probe I disorder Résumé ― Présence d'Escherichia coli productrices des cytotoxines CNF1 et CNF2 coli strains in a collection of 553 E coli isolates from cattle, sheep, goats, pigs, horses, dogs, cats

Paris-Sud XI, Université de

303

Escherichia coli K88 adhesion : A comparison of Chinese and Large White piglets  

E-print Network

Note Escherichia coli K88 adhesion : A comparison of Chinese and Large White piglets J.P. CHAPPUIS : K88 adhesion, E. coli, pig, genetic resistance. Résumé L'attachement de Escherichia coli K88, maintained in plastic film isolators. Shortly after successive oral inoculations of 2 E. coli strains, one K

Paris-Sud XI, Université de

304

Slugs: Potential Novel Vectors of Escherichia coli O157  

PubMed Central

Field and laboratory studies were performed to determine whether slugs could act as novel vectors for pathogen (e.g., Escherichia coli O157) transfer from animal feces to salad vegetables. Escherichia coli O157 was isolated from 0.21% of field slugs from an Aberdeenshire sheep farm. These isolates carried the verocytotoxin genes (vt1 and vt2) and the attaching and effacing gene (eae), suggesting that they are potentially pathogenic to humans. Strain typing using multilocus variable number tandem repeats analysis showed that slug and sheep isolates were indistinguishable. Laboratory experiments using an E. coli mutant resistant to nalidixic acid showed that the ubiquitous slug species Deroceras reticulatum could carry viable E. coli on its external surface for up to 14 days. Slugs that had been fed E. coli shed viable bacteria in their feces with numbers showing a short but statistically significant linear log decline. Further, it was found that E. coli persisted for up to 3 weeks in excreted slug feces, and hence, we conclude that slugs have the potential to act as novel vectors of E. coli O157. PMID:16391036

Sproston, Emma L.; Macrae, M.; Ogden, Iain D.; Wilson, Michael J.; Strachan, Norval J. C.

2006-01-01

305

Slugs: potential novel vectors of Escherichia coli O157.  

PubMed

Field and laboratory studies were performed to determine whether slugs could act as novel vectors for pathogen (e.g., Escherichia coli O157) transfer from animal feces to salad vegetables. Escherichia coli O157 was isolated from 0.21% of field slugs from an Aberdeenshire sheep farm. These isolates carried the verocytotoxin genes (vt1 and vt2) and the attaching and effacing gene (eae), suggesting that they are potentially pathogenic to humans. Strain typing using multilocus variable number tandem repeats analysis showed that slug and sheep isolates were indistinguishable. Laboratory experiments using an E. coli mutant resistant to nalidixic acid showed that the ubiquitous slug species Deroceras reticulatum could carry viable E. coli on its external surface for up to 14 days. Slugs that had been fed E. coli shed viable bacteria in their feces with numbers showing a short but statistically significant linear log decline. Further, it was found that E. coli persisted for up to 3 weeks in excreted slug feces, and hence, we conclude that slugs have the potential to act as novel vectors of E. coli O157. PMID:16391036

Sproston, Emma L; Macrae, M; Ogden, Iain D; Wilson, Michael J; Strachan, Norval J C

2006-01-01

306

Inactivation of Escherichia coli by titanium dioxide photocatalytic oxidation.  

EPA Science Inventory

Titanium dioxide in the anatase crystalline form was used as a photocatalyst to generate hydroxyl radicals in a flowthrough water reactor. Experiments were performed on pure cultures of Escherichia coli in dechlorinated tap water and a surface water sample to evaluate the disinfe...

307

Regulated expression of the Escherichia coli dam gene.  

PubMed

Regulated expression of the Escherichia coli dam gene has been achieved with the araBAD promoter lacking a ribosome binding site. Cultures of dam mutants containing plasmid pMQ430 show no detectable methylation in the absence of arabinose and complete methylation in its presence. Dam methyltransferase is a substrate for the Lon protease. PMID:12897023

Calmann, Melissa A; Marinus, M G

2003-08-01

308

Regulated Expression of the Escherichia coli dam Gene  

Microsoft Academic Search

Regulated expression of the Escherichia coli dam gene has been achieved with the araBAD promoter lacking a ribosome binding site. Cultures of dam mutants containing plasmid pMQ430 show no detectable methylation in the absence of arabinose and complete methylation in its presence. Dam methyltransferase is a substrate for the Lon protease.

Melissa A. Calmann; M. G. Marinus

2003-01-01

309

A DNA structural atlas for Escherichia coli1  

Microsoft Academic Search

We have performed a computational analysis of DNA structural features in 18 fully sequenced prokaryotic genomes using models for DNA curva- ture, DNA flexibility, and DNA stability. The structural values that are computed for the Escherichia coli chromosome are significantly different from (and generally more extreme than) that expected from the nucleo- tide composition. To aid this analysis, we have

Anders Gorm Pedersen; Lars Juhl Jensen; Søren Brunak; Hans-Henrik Stærfeldt; David W. Ussery

2000-01-01

310

Evolution of Escherichia coli During Growth in a Constant Environment  

Microsoft Academic Search

Populations of Escherichia coli, initiated with a single clone and maintained for long periods in glucose-limited continuous culture, developed extensive polymorphisms. In one population, examined after 765 generations, two majority and two minority types were identified. Stable mixed populations were reestablished from the isolated strains. Factors involved in the development of this polymorphism included differences in the maximum specific growth

Robert B. Helling; Christopher N. Vargas; Julian Adams

1987-01-01

311

Periodicity of cell attachment patterns during Escherichia coli biofilm development.  

PubMed

The complex architecture of bacterial biofilms inevitably raises the question of their design. Microstructure of developing Escherichia coli biofilms was analyzed under static and laminar flow conditions. Cell attachment during early biofilm formation exhibited periodic density patterns that persisted during development. Several models for the origination of biofilm microstructure are considered, including an activator-inhibitor or Turing model. PMID:12949116

Agladze, Konstantin; Jackson, Debra; Romeo, Tony

2003-09-01

312

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

313

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. PMID:4963790

Hernandez, Eovaldo; Johnson, Marvin J.

1967-01-01

314

Genetics of ribosomal protein methylation in Escherichia coli  

Microsoft Academic Search

Two genes governing ribosomal protein methylation have been located on the map of Escherichia coli by conjugation and transduction crosses between wild-type and prm (protein methylation) mutants. The Prm phenotype of recombinants was determined by an in vitro assay of methylgroups incorporation into protein.

Charles Colson; Jacques Lhoest; Colette Urlings

1979-01-01

315

Patchiness of murein insertion into the sidewall of Escherichia coli  

Microsoft Academic Search

This paper extends, with computer techniques, the authors' previous work on the kinetics of pole wall and sidewall synthesis in Escherichia coli. These findings extend the conclusion that the nascent poles are made of entirely new material and that no new material is inserted into old poles. This requires re-evaluation of ideas in the literature about wall growth and cell

Miguel A. De Pedro; Heinz Schwarz; Arthur L. Koch

2003-01-01

316

Precursor-directed biosynthesis of curcumin analogs in Escherichia coli.  

PubMed

Curcuminoids, natural products in the rhizome of turmeric, show various biological activities, including antioxidant and antitumor activities. For this reason, curcuminoids have been focused on as potential pharmaceuticals. Exogenous supplementation with various carboxylate precursors in genetically engineered Escherichia coli cells carrying an artificially assembled pathway for curcuminoid biosynthesis led to the production of 17 unnatural curcuminoids. PMID:20208337

Katsuyama, Yohei; Hirose, Yutaka; Funa, Nobutaka; Ohnishi, Yasuo; Horinouchi, Sueharu

2010-01-01

317

Standard reference strains of Escherichia coli from natural populations.  

PubMed Central

A set of 72 reference strains of Escherichia coli isolated from a variety of hosts and geographical locations has been established for use in studies of variation and genetic structure in natural populations. The strains, which have been characterized by multilocus enzyme electrophoresis, are representative of the range of genotypic variation in the species as a whole. PMID:6363394

Ochman, H; Selander, R K

1984-01-01

318

Escherichia coli K-12: a cooperatively developed annotation snapshot--2005  

Microsoft Academic Search

The goal of this group project has been to coordinate and bring up-to-date information on all genes of Escherichia coli K-12. Annotation of the genome of an organism entails identification of genes, the boundaries of genes in terms of precise start and end sites, and description of the gene products. Known and predicted functions were assigned to each gene product

Monica Riley; Takashi Abe; Martha B. Arnaud; Mary K. B. Berlyn; Frederick R. Blattner; Roy R. Chaudhuri; Jeremy D. Glasner; Takashi Horiuchi; Ingrid M. Keseler; Takehide Kosuge; Hirotada Mori; Nicole T. Perna; Guy Plunkett; Kenneth E. Rudd; Margrethe H. Serres; Gavin H. Thomas; Nicholas R. Thomson; David Wishart; Barry L. Wanner

2006-01-01

319

Identification of the Escherichia coli Nicotinic Acid Mononucleotide Adenylyltransferase Gene  

PubMed Central

The gene (ybeN) coding for nicotinate mononucleotide adenylyltransferase, an NAD(P) biosynthetic enzyme, has been identified and overexpressed in Escherichia coli. This enzyme catalyzes the reversible adenylation of nicotinate mononucleotide and shows product inhibition. The rate of adenylation of nicotinate mononucleotide is at least 20 times faster than the rate of adenylation of nicotinamide mononucleotide. PMID:10894752

Mehl, Ryan A.; Kinsland, Cynthia; Begley, Tadhg P.

2000-01-01

320

Global Incidence of Carbapenemase-Producing Escherichia coli ST131  

PubMed Central

We characterized Escherichia coli ST131 isolates among 116 carbapenemase-producing strains. Of isolates from 16 countries collected during 2008–2013, 35% belonged to ST131 and were associated with blaKPC, H30 lineage, and virotype C. This study documents worldwide incidents of resistance to “last resort” antimicrobial drugs among a common pathogen in a successful sequence type. PMID:25340464

Peirano, Gisele; Bradford, Patricia A.; Kazmierczak, Krystyna M.; Badal, Robert E.; Hackel, Meredith; Hoban, Daryl J.

2014-01-01

321

The Asymmetric Flagellar Distribution and Motility of Escherichia coli  

Microsoft Academic Search

Rod-shaped bacteria such as Escherichia coli divide by binary fission. They inherit an old pole from the parent cell. The new pole is recently derived from the septum. Because the chemoreceptor accumulates linearly with time on the cell pole, the old pole carries more receptors than does the new pole. Here, further evidence is provided that the old pole appears

Liyan Ping

2010-01-01

322

Evidence for a human-specific Escherichia coli clone  

Microsoft Academic Search

Summary Escherichia coli is a widespread commensal of the vertebrate intestinal tract. Until recently, no strong association between a particular clone and a given host species has been found. However, members of the B2 subgroup VIII clone with an O81 serotype appear to be human host specific. To determine the degree of host specificity exhibited by this clone, a PCR-based

Olivier Clermont; Mathilde Lescat; Claire L. O'Brien; David M. Gordon; Olivier Tenaillon; Erick Denamur

2008-01-01

323

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...

324

Original article Resistance of Escherichia coli growing as biofilms  

E-print Network

Original article Resistance of Escherichia coli growing as biofilms to disinfectants C Ntsama by culture on tryptic soy agar (in-suspension or on-germ-carrier test) or in the form of biofilms pro- duced in a continuous culture system. The bacteria tested on germ-carriers or included in biofilms were more resistant

Boyer, Edmond

325

Maternally acquired genotoxic Escherichia coli alters offspring's intestinal homeostasis.  

PubMed

The neonatal gut is rapidly colonized by a newly dominant group of commensal Escherichia coli strains among which a large proportion produces a genotoxin called colibactin. In order to analyze the short- and long-term effects resulting from such evolution, we developed a rat model mimicking the natural transmission of E. coli from mothers to neonates. Genotoxic and non-genotoxic E. coli strains were equally transmitted to the offspring and stably colonized the gut across generations. DNA damage was only detected in neonates colonized with genotoxic E. coli strains. Signs of genotoxic stress such as anaphase bridges, higher occurrence of crypt fission and accelerated renewal of the mature epithelium were detected at adulthood. In addition, we observed alterations of secretory cell populations and gut epithelial barrier. Our findings illustrate how critical is the genotype of E. coli strains acquired at birth for gut homeostasis at adulthood. PMID:24971581

Payros, Delphine; Secher, Thomas; Boury, Michèle; Brehin, Camille; Ménard, Sandrine; Salvador-Cartier, Christel; Cuevas-Ramos, Gabriel; Watrin, Claude; Marcq, Ingrid; Nougayrède, Jean-Philippe; Dubois, Damien; Bedu, Antoine; Garnier, Fabien; Clermont, Olivier; Denamur, Erick; Plaisancié, Pascale; Theodorou, Vassilia; Fioramonti, Jean; Olier, Maïwenn; Oswald, Eric

2014-01-01

326

Experimental Escherichia coli ascending pyelonephritis in rats: active peroral immunization with live Escherichia coli.  

PubMed Central

Peroral immunization with a live strain of Escherichia coli O6K13H1 against experimental ascending pyelonephritis caused by the same strain was studied in rats, and the effect of immunization on antibody titers against the O and K antigens and lipid A was determined. Peroral immunization with live bacteria protected significantly against pyelonephritis. Sera collected 1 week after infection from the immunized group were increased in immunoglobulin G (IgG) anti-O6 and IgM anti-K13 in comparison with the nonimmunized group. The peroral immunization did not correspondingly affect the response to lipid A. In urine, there was an IgG antibody response to the O6 antigen. In bronchopulmonary secretion, IgM, IgG, and IgA antibodies to O6 were detected. Perorally immunized animals had significantly higher levels of IgG and IgA anti-O6 compared with the nonimmunized group 1 week after infection. Passive transfer of anti-lipid A did not increase resistance against pyelonephritis. PMID:7035370

Mattsby-Baltzer, I; Hanson, L A; Olling, S; Kaijser, B

1982-01-01

327

Estimation of Escherichia coli in raw ground beef.  

PubMed Central

This study was undertaken to establish and evaluate more rapid methods of estimating Escherichia coli in ground beef than the standard most probable number (MPN) technique. Direct inoculation of and modifications to EC medium gave unreliable estimates of the presumptive E. coli count. Solid media incubated at an elevated temperature were compared to the MPN technique. Anderson and Baird-Parker's tryptone bile agar (TBA) method and prepoured plates of Endo, Levine eosin methylene blue (EMB), and violet red bile (VRBA) agars incubated at 44 degree C gave equivalent counts to the standard MPN method. Anderson and Baird-Parker TBA was the most selective solid medium for E. coli estimation, but all selective media incubated at elevated temperature reduced apparent E. coli counts by as much as 50%. Indole-producing and lactose-fermenting Enterobacteriaceae, capable of growth at elevated temperature, were tested for their growth on TBA, EMB, and VRBA at elevated temperature. TBA was selective for E. coli biotype I compared to other Enterobacteriaceae that predominate in meats. VRBA and EMB incubated at elevated temperature were not as selective as TBA, but differences in colonies could be observed between typical E. coli colonies and other Enterobacteriaceae on these media. Therefore, VRBA incubated at elevated temperature is proposed as a quality assurance screening test for presumptive E. coli in ground meat. Resuscitation techniques and prepoured plates with VRBA increased recovery levels of presumptive E. coli, but, under the conditions of this study, not to levels that represented a significant practical difference. PMID:7008695

Stiles, M E; Ng, L K

1980-01-01

328

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. PMID:20031048

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

329

Steady-State Chemotaxis in Escherichia coli  

Microsoft Academic Search

The bacterium E. coli maneuvers itself to regions with high chemoattractant concentrations by performing two stereotypical moves: ``runs,'' in which it moves in near-straight lines, and ``tumbles,'' in which it does not advance but changes direction randomly. The duration of each move is stochastic and depends upon the chemoattractant concentration experienced in the recent past. We relate this stochastic behavior

Yariv Kafri; Rava Azeredo da Silveira

2008-01-01

330

Temporal Stimulation of Chemotaxis in Escherichia coli  

Microsoft Academic Search

We used the tracking microscope to study the chemotactic responses of E. coli to temporal gradients of L-glutamate generated in isotropic solutions by the action of the enzyme alanine aminotransferase. Positive gradients suppress directional changes which occur spontaneously in the absence of a stimulus. Negative gradients have little effect. The data can be fit with a model in which the

Douglas A. Brown; Howard C. Berg

1974-01-01

331

Food-borne origins of Escherichia coli causing extraintestinal infections.  

PubMed

Most human extraintestinal Escherichia coli infections, including those involving antimicrobial resistant strains, are caused by the members of a limited number of distinctive E. coli lineages, termed extraintestinal pathogenic E. coli (ExPEC), that have a special ability to cause disease at extraintestinal sites when they exit their usual reservoir in the host's intestinal tract. Multiple lines of evidence suggest that many of the ExPEC strains encountered in humans with urinary tract infection, sepsis, and other extraintestinal infections, especially the most extensively antimicrobial-resistant strains, may have a food animal source, and may be transmitted to humans via the food supply. This review summarizes the evidence that food-borne organisms are a significant cause of extraintestinal E. coli infections in humans. PMID:22615330

Manges, Amee R; Johnson, James R

2012-09-01

332

Polyserositis Induced by Escherichia coli in Gnotobiotic Swine.  

PubMed

The oral administration of an 18-hr broth culture of Escherichia coli 06: isolated from a cat to 3-day-old gnotobiotic (germ-free) piglets resulted in bacteremia and polyserositis. Sixteen pigs, selected from four litters, were used in the study. E. coli of the same serotype employed was the only bacterial agent demonstrable and recovered from moribund and dead piglets. Attempts to recover virus or PPLO (mycoplasma) from these animals were unsuccessful. A polyserositis syndrome was not encountered among neonatal pigs in experiments with 14 other serotypes of E. coli; hence it was considered to be a syndrome closely associated with the infection caused by this particular strain of E. coli. PMID:16557944

Meyer, R C; Saxena, S P; Rhoades, H E

1971-01-01

333

Biosynthesis of bioactive O-methylated flavonoids in Escherichia coli.  

PubMed

Two bioactive O-methylflavonoids, sakuranetin (7-O-methylnaringenin) and ponciretin (7-O-methylnaringenin), were synthesized in Escherichia coli. Sakuranetin inhibits germination of Magnaporthe grisea, and ponciretin is a potential inhibitor of Helicobacter pylori. To achieve this, we reconstructed the naringenin biosynthesis pathway in E. coli. First, the shikimic acid pathway, which leads to the biosynthesis of tyrosine, was engineered in E. coli to increase the amount of available tyrosine. Second, several genes for the biosynthesis of ponciretin and sakuranetin such as tyrosine ammonia lyase (TAL), 4-coumaroyl CoA ligase (4CL), chalcone synthase (CHS), and O-methyltransferase (OMT) were overexpressed. In order to increase the supply the Coenzyme A (CoA), one gene (icdA, isocitrate dehydrogenase) was deleted. Using these strategies, we synthesized ponciretin and sakuranetin from glucose in E. coli at the concentration of 42.5 mg/L and 40.1 mg/L, respectively. PMID:23771780

Kim, Min-Ji; Kim, Bong-Gyu; Ahn, Joong-Hoon

2013-08-01

334

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. PMID:23872574

Frömmel, Ulrike; Lehmann, Werner; Rödiger, Stefan; Böhm, Alexander; Nitschke, Jörg; Weinreich, Jörg; Groß, Julia; Roggenbuck, Dirk; Zinke, Olaf; Ansorge, Hermann; Vogel, Steffen; Klemm, Per; Wex, Thomas; Schröder, Christian; Wieler, Lothar H.

2013-01-01

335

ROLE OF NUTRITION IN THE PATHOGENESIS OF PORCINE ESCHERICHIA COLI ENTEROTOXAEMIA  

E-print Network

ROLE OF NUTRITION IN THE PATHOGENESIS OF PORCINE ESCHERICHIA COLI ENTEROTOXAEMIA H.U. BERTSCHINGER growth of a few serotypes of haemolytic E. coli in the small intestine. Correspondingly to E. coli. coli enterotoxaemia was studied in weaned pigs inoculated with a field strain of E. coli 0139:K821BI

Boyer, Edmond

336

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. PMID:23391439

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

337

Genetic Transformation in Escherichia coli K12  

Microsoft Academic Search

An auxotrophic strain of E. coli K12 treated with CaCl2 was transformed for several markers at a frequency of up to 10-6 per recipient cell by a DNA preparation isolated from a prototrophic strain. The transforming activity of the DNA preparation was eliminated by treatment with DNase, heat, or sonication, whereas RNase or Pronase treatment had little effect. Two closely

Sharon D. Cosloy; Michio Oishi

1973-01-01

338

DNA Methylation and Mutator Genes in Escherichia coli K-12  

PubMed Central

Mutator strains of Escherichia coli have been used to define mechanisms that account for the high fidelity of chromosome duplication and chromosome stability. Mutant strains defective in post-replicative mismatch repair display a strong mutator phenotype consistent with a role for correction of mismatches arising from replication errors. Inactivation of the gene (dam) encoding DNA adenine methyltransferase results in a mutator phenotype consistent with a role for DNA methylation in strand discrimination during mismatch repair. This review gives a personal perspective on the discovery of dam mutants in E. coli and their relationship to mismatch repair and mutator phenotypes. PMID:20471491

Marinus, Martin G.

2010-01-01

339

Copper, zinc superoxide dismutase in Escherichia coli: periplasmic localization.  

PubMed

Cu,ZnSOD purified from Escherichia coli has been used to raise antibodies in rabbits. The resultant antiserum was found to recognize a single band on Western blots of SDS-polyacrylamide gel electropherograms, and that single band coincided with the position of the Cu,ZnSOD. Ultrathin sections of fixed E. coli were treated with the antibody followed by protein A bearing 10-nm gold particles. Electron microscopy revealed that Cu,ZnSOD was largely localized in the periplasm in polar bays. PMID:7786035

Benov, L; Chang, L Y; Day, B; Fridovich, I

1995-06-01

340

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

341

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. PMID:7828983

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

1994-01-01

342

Uncoupler Resistance in Escherichia coli: the Role of Cellular Respiration  

Microsoft Academic Search

Bioenergetic properties of a mutant strain of Escherichia coli K12 designated TUV, which is resistant to the protonophoric uncoupling agent 4,5,6,7-tetrachloro-2-trifluoromethylbenzimid- azole (TTFB) have been compared with those of its non-resistant parent, E. coli K12 Doc-S. Strain TUV grew and respired some 20-30% faster than strain Doc-S, and was cross-resistant to carbonylcyanide p-(trifluoromethoxy)phenylhydrazone and triphenyltin, but not to 2,4- dinitrophenol.

PHILIP G. QUIRK; MICHAEL R. JONES; ROBERT S. HAWORTH; R. BRIAN BEECHEY; IAIN D. CAMPBELL

1989-01-01

343

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. PMID:24860555

Rosano, German L.; Ceccarelli, Eduardo A.

2014-01-01

344

DNA methylation and mutator genes in Escherichia coli K-12.  

PubMed

Mutator strains of Escherichia coli have been used to define mechanisms that account for the high fidelity of chromosome duplication and chromosome stability. Mutant strains defective in post-replicative mismatch repair display a strong mutator phenotype consistent with a role for correction of mismatches arising from replication errors. Inactivation of the gene (dam) encoding DNA adenine methyltransferase results in a mutator phenotype consistent with a role for DNA methylation in strand discrimination during mismatch repair. This review gives a personal perspective on the discovery of dam mutants in E. coli and their relationship to mismatch repair and mutator phenotypes. PMID:20471491

Marinus, Martin G

2010-10-01

345

Bacterial self-defence: how Escherichia coli evades serum killing.  

PubMed

The ability to survive the bactericidal action of serum is advantageous to extraintestinal pathogenic Escherichia coli that gain access to the bloodstream. Evasion of the innate defences present in serum, including complement and antimicrobial peptides, involves multiple factors. Serum resistance mechanisms utilized by E. coli include the production of protective extracellular polysaccharide capsules and expression of factors that inhibit or interfere with the complement cascade. Recent studies have also highlighted the importance of structural integrity of the cell envelope in serum survival. These survival strategies are outlined in this review with particular attention to novel findings and recent insights into well-established resistance mechanisms. PMID:24617921

Miajlovic, Helen; Smith, Stephen G

2014-05-01

346

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; Muñoz-Villagrán, Claudia M; de la Torre, Erick; Tantaleán, Juan C; Vásquez, Claudio C; Pérez-Donoso, José M

2012-01-01

347

Determination and quantification of Escherichia coli by capillary electrophoresis.  

PubMed

Capillary electrophoresis (CE) is widely employed for the separation of nucleic acids or protein, but it is rarely applied in the quantification of Escherichia coli (E. coli). Here, we have analysed E. coli by CE with mercury lamp induced fluorescence, and demonstrated the relationship between its fluorescence intensity with the concentration of E. coli for the first time. The gradient concentration of E. coli was obtained by polymerase chain reaction (PCR) with different amplification cycles and dilution certain PCR products of E. coli, respectively. Results show that the peak area was linearly related to the logarithm of the concentration of E. coli and the logarithm of PCR replication numbers. The correlation coefficients R(2) are 0.957 and 0.966, respectively. The limit of detection (LOD) was found to be about 8.913 × 10(-15) mol ?l(-1). The reproducibility of capillary electrophoresis may make this technique possible for quantitative measurement of bacteria in bio-analytical science. PMID:25307062

Li, Zhenqing; Li, De; Zhang, Dawei; Yamaguchi, Yoshinori

2014-10-27

348

Escherichia Coli: an Important Pathogen in Patients with Hematologic Malignancies  

PubMed Central

Background Escherichia coli (E. coli) is a pathogen of great concern in immunosuppressed patients. While antimicrobial prophylactic therapy has become the standard, the emergence of resistant pathogens has some questioning its use. This study describes our experience with E.coli as a pathogen in neutropenic patients with a hematologic malignancy, and addresses future directions of treatment for this patient population. Methods A retrospective chart review of 245 E.coli bacteremia patients at Moffitt Cancer Center from 05/18/02 – 05/15/12 was conducted. Out of 245 patients, 169 did not meet the criteria due to non-neutropenic status, or not diagnosed with a hematologic malignancy, or due to having insufficient medical records. Thus, they were excluded from the study. As a result, 76 patients were involved in this study. Patients were identified via microbiology laboratory computerized records. Results The included patients experienced clinically significant E.coli bacteremia resulting in a median hospital stay of 14.7 days. Several patients developed severe sepsis requiring the use of pressor and ventilator therapy. Conclusions E.coli is a major pathogen in these patient populations resulting in extended hospital stays and specialized treatment to overcome their E.coli bacteremia. The data supports the use of fluoroquinolone prophylactic therapy, however, earlier detection and treatment of neutropenic infection is needed. PMID:25408854

Olson, Daniel; Yacoub, Abraham T.; Gjini, Anita D.; Domingo, Gelenis; Greene, John N.

2014-01-01

349

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. PMID:24265928

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

2013-01-01

350

Competitive inhibition of adherence of enterotoxigenic Escherichia coli, enteropathogenic Escherichia coli and Clostridium difficile to intestinal epithelial cell line Lovo by purified adhesin of Bifidobacterium adolescentis 1027  

Microsoft Academic Search

AIM: To observe competitive inhibition of adherence of enterotoxigenic Escherichia coli (ETEC), enteropathogenic Escherichia coli (EPEC) and Clostridium difficile (C. difficile) to intestinal epithelial cell line Lovo by purified adhesin of Bifidobacterium adolescentis 1027 (B. ado 1027). METHODS: The binding of bacteria to intestinal epithelial cell line Lovo was counted by adhesion assay. The inhibition of adherence of ETEC, EPEC

Shi-Shun Zhong; Zhen-Shu Zhang; Ji-De Wang; Zhuo-Sheng Lai; Qun-Ying Wang; Ling-Jia Pan; Yue-Xin Ren

2004-01-01

351

Transcriptome-based determination of multiple transcription regulator activities in Escherichia coli  

E-print Network

network connectiv- ity. We used Escherichia coli carbon source transition from glucose to acetate the Escherichia coli transition from glucose to acetate media as an example. When switching from a glycolyticTranscriptome-based determination of multiple transcription regulator activities in Escherichia

Sabatti, Chiara

352

In vivo translation rates can substantially delay the cotranslational folding of the Escherichia coli  

E-print Network

results indicate that, at in vivo translation rates, about one-third of the Escherichia coli cytosolic in Escherichia coli's proteome. systems biology | synonymous codons | chemical kinetics | chaperone | aggregationIn vivo translation rates can substantially delay the cotranslational folding of the Escherichia

Morimoto, Richard

353

An Experimental Evolutionary Study on Adaptation to Temporally Fluctuating pH in Escherichia coli  

E-print Network

Published 5/2/2007 ABSTRACT In this study, we use the bacterium Escherichia coli to examine evolutionary because of the importance of this environmental stressor to enteric bac- teria such as Escherichia coli406 An Experimental Evolutionary Study on Adaptation to Temporally Fluctuating pH in Escherichia

Bennett, Albert F.

354

Variation of the folding and dynamics of the Escherichia coli chromosome with growth conditions  

E-print Network

Variation of the folding and dynamics of the Escherichia coli chromosome with growth conditions Biosciences, Northwestern University, Evanston, IL 60208, USA. Summary We examine whether the Escherichia coli slow growth where there is one complete cycle of DNA replica- tion per cell division, the Escherichia

Kowalczykowski, Stephen C.

355

A Case of a Shiga Toxin Producing Escherichia Coli  

E-print Network

contributed equally to this work. We encountered a patient with hemolytic uremic syndrome (HUS) with persistent isolation of shiga toxin-producing Escherichia coli (STEC) for 3 weeks despite of having no clinical symptoms. STEC has been recognized as an important foodborne pathogen that causes severe diseases such as HUS. We characterized this STEC strain via a polymerase chain reaction, reverse-passive latex agglutination and the slide agglutination method. In this STEC strain, stx2 (shiga toxin), eaeA, tir, iha (adherence genes), espADB (type III secretion genes), and hlyA, ehxA, clyA (hemolysin genes) were present. The O antigen of the strain was non-typable. Key Words: ?Shiga toxin-producing Escherichia coli, hemolytic uremic syndrome, non-typable serotype STEC strain ? The authors have no financial conflicts of

Seung-hak Cho Jung-beom Kim; Hiun Suk Chae; Hae Kyung Lee; Corresponding Dr; Hae Kyung Lee; Seung-hak Cho; Jung-beom Kim

2011-01-01

356

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

357

Evaluating Representations for the Shine-Dalgarno Site in Escherichia coli  

E-print Network

Evaluating Representations for the Shine-Dalgarno Site in Escherichia coli Steven Hampson & Dennis 10) are applied to the pooled Upstream Regions (USR) of all 4289 Escherichia coli ORFs. Instances) but most genes in E. coli have an identifiable SD sequence in the expected location. On the other hand, up

Kibler, Dennis F.

358

LETTER TO THE EDITOR Aminoacylated tmRNA from Escherichia coli  

E-print Network

LETTER TO THE EDITOR Aminoacylated tmRNA from Escherichia coli interacts with prokaryoticRNAs (10Sa RNAs) are unique because they function, at least in Escherichia coli, both as tRNA and mRNA (for frame coding for 9 to 27 amino acids, depending on the species+ E. coli tmRNA mediates re- cycling

Paris-Sud XI, Université de

359

Design and Diversity in Bacterial Chemotaxis: A Comparative Study in Escherichia coli  

E-print Network

Design and Diversity in Bacterial Chemotaxis: A Comparative Study in Escherichia coli and Bacillus such as Escherichia coli and Bacillus subtilis, swimming alternates between smooth runs and reorientating tumbles, in particular the feedback control structure, is also conserved. The bacterial chemotaxis pathways in E. coli

Fernando, Chrisantha

360

The Roles of Specific Template Nucleosides in the Formation of Stable Transcription Complexes by Escherichia coli  

E-print Network

by Escherichia coli RNA Polymerase* (Received for publication, September 13, 1999, and in revised form, December/or initiation. The initiation of transcription by Escherichia coli RNA po- lymerase involves not only DNA nucleosides on promoter escape by Esche- richia coli RNA polymerase in vitro. The ability of DNA templates

Tullius, Thomas D.

361

Is there a Liquid State Machine in the Bacterium Escherichia Coli?  

E-print Network

Is there a Liquid State Machine in the Bacterium Escherichia Coli? Ben Jones, Dov Stekelo, Jon Rowe, UK Email: C.T.Fernando@cs.bham.ac.uk Abstract-- The bacterium Escherichia coli has the capacity, E.Coli's capacity for perceptual categorization, especially for discrimination between complex

Rowe, Jon

362

Escherichia coli identification and strain discrimination using nanosecond laser-induced breakdown spectroscopy  

E-print Network

Escherichia coli identification and strain discrimination using nanosecond laser-induced breakdown April 2007 Three strains of Escherichia coli, one strain of environmental mold, and one strain and E. coli strains. This analysis showed efficient discrimination between laser-induced breakdown

Rehse, Steven J.

363

THE TEMPERATURE-LIMITED FED-BATCH TECHNIQUE FOR CONTROL OF ESCHERICHIA COLI CULTURES  

E-print Network

THE TEMPERATURE-LIMITED FED-BATCH TECHNIQUE FOR CONTROL OF ESCHERICHIA COLI CULTURES MARIE SVENSSON The objective of this study was to investigate the physiology and productivity in Escherichia coli cultures of endotoxins were found in the medium of E. coli fed-batch cultures at low specific growth rates (below 0.1 h-1

Enfors, Sven-Olof

364

Development of a Native Escherichia coli Induction System for Ionic Liquid Tolerance  

E-print Network

Development of a Native Escherichia coli Induction System for Ionic Liquid Tolerance Marijke the growth and function of biofuel-producing microorganisms. In E. coli this toxicity can be partially J, Batth TS, Turner WJ, et al. (2014) Development of a Native Escherichia coli Induction System

Dunlop, Mary

365

A Novel Methyltransferase Catalyzes the Methyl Esterification of trans-Aconitate in Escherichia coli*  

E-print Network

-adenosyl-L-methi- onine-dependent methyltransferase in the cytosol of Escherichia coli that is expressed in early-out strain of E. coli lacking this activity, and we find that its growth and stationary phase survival). In the bacterium Escherichia coli, this enzyme is required for optimal survival of stationary phase cells against

Clarke, Steven

366

Antisense phosphorodiamidate morpholino oligomer inhibits viability of Escherichia coli in pure culture  

E-print Network

Antisense phosphorodiamidate morpholino oligomer inhibits viability of Escherichia coli in pure of Escherichia coli. Previously, an 11 base PMO targeted to an essential gene (acpP) for phospholipid biosynthesis was shown to inhibit growth of a pure culture of E. coli AS19, which has an abnormally permeable

Hammerton, James

367

CONTROL OF PYRIMIDINE BIOSYNTHESIS IN ESCHERICHIA COLI BY A FEED-BACK MECHANISM*  

E-print Network

CONTROL OF PYRIMIDINE BIOSYNTHESIS IN ESCHERICHIA COLI BY A FEED-BACK MECHANISM* BY RICHARD A of purine- requiring Escherichia coli mutants caused inhibition of formation of two purine precursors the growth factor, valine, inhibited formation in an E. coli mutant of a-ketoisovalerate, a valine precursor

Bulyk, Martha L.

368

Self-Organization of the Escherichia coli Chemotaxis Network Imaged with Super-Resolution Light Microscopy  

E-print Network

Self-Organization of the Escherichia coli Chemotaxis Network Imaged with Super-Resolution Light of California Berkeley, Berkeley, California, United States of America Abstract The Escherichia coli chemotaxis network is a model system for biological signal processing. In E. coli, transmembrane receptors

369

AICAR is not an endogenous mutagen in Escherichia coli  

Microsoft Academic Search

A number of observations in the Escherichia coli and Salmonella typhimurium literature could be explained by the hypothesis that a particular purine ribonucleotide precursor can be converted to the corresponding deoxyribonucleotide triphosphate, thereby becoming a base-analogue mutagen. The metabolite in question, AICAR (5-amino-4-carboxamide imidazole riboside 5'-phosphate), is also a by-product of histidine biosynthesis, and its (ribo)triphosphate derivative, ZTP, has been

Maurice Fox; Niels Frandsen; Richard D'Ari

1993-01-01

370

On Torque and Tumbling in Swimming Escherichia coli  

Microsoft Academic Search

Bacteria swim by rotating long thin helical filaments, each driven at its base by a reversible rotary motor. When the motors of peritrichous cells turn counterclockwise (CCW), their filaments form bundles that drive the cells forward. We imaged fluorescently labeled cells of Escherichia coli with a high-speed charge-coupled- device camera (500 frames\\/s) and measured swimming speeds, rotation rates of cell

Nicholas C. Darnton; Linda Turner; Svetlana Rojevsky; Howard C. Berg

2007-01-01

371

Escherichia coli lipopolysaccharide inhibits renin activity in human mesangial cells  

Microsoft Academic Search

Hyperactivation of systemic renin–angiotensin system (RAS) during sepsis is well documented. However, the behavior of intrarenal RAS in the context of endotoxemia is yet to be defined. The present study evaluates the direct effect of Escherichia coli lipopolysaccharide (LPS) on immortalized human mesangial cell (HMC) RAS. Quiescent HMC were incubated with vehicle or LPS (1–100 ?g\\/ml), and levels of angiotensin

W S Almeida; T T Maciel; G S Di Marco; D E Casarini; A H Campos; N Schor

2006-01-01

372

Expression and characterization of Pichia etchellsii ?-glucosidase in Escherichia coli  

Microsoft Academic Search

The ?-glucosidase enzyme is important as the terminal enzyme involved in hydrolysis of cellobiose and short-chain cellodextrins generated during enzymatic cellulose degradation. Under controlled reaction conditions the enzyme also displays cello-oligosaccharide synthesizing ability (based on either the thermodynamic or kinetic approach). We present here the purification of the enzyme ?-glucosidase (BGL) of Pichia etchellsii from recombinant pBG55 Escherichia coli clone.

Manjula Pandey; Saroj Mishra

1997-01-01

373

Electric field induced bacterial flocculation of enteroaggregative Escherichia coli 042  

NASA Astrophysics Data System (ADS)

A response of the aggregation dynamics of enteroaggregative Escherichia coli under low magnitude steady and oscillating electric fields is presented. The presence of uniform electric fields hampered microbial adhesion and biofilm formation on a transverse glass surface, but instead promoted the formation of flocs. Extremely heterogenous distribution of live and dead cells was observed among the flocs. Moreover, floc formation was largely observed to be independent of the frequency of alternating electric fields.

Kumar, Aloke; Mortensen, Ninell P.; Mukherjee, Partha P.; Retterer, Scott T.; Doktycz, Mitchel J.

2011-06-01

374

Effect of acid mine water on Escherichia coli : Structural Damage  

Microsoft Academic Search

Escherichia coli B\\/5 12-h cultures were exposed to filter-sterilized acid mine water (AMW), fixed in situ, and examined for morphological changes by transmission electron microscopy, scanning electron microscopy, and x-ray spectrometry. Thin sections showed that layers of the Gram-negative envelope were altered and often lacking. Additionally, polar regions of the cell were frequently devoid of cytoplasm. AMW-exposed cells were distorted

Alan T. Wortman; H. Voelz; R. Clark Lantz; Gary K. Bissonnette

1986-01-01

375

Evidence of Pathogenic Subgroups among Atypical Enteropathogenic Escherichia coli Strains?  

PubMed Central

We describe the characterization of 126 atypical enteropathogenic Escherichia coli (aEPEC) isolates from 1,749 Brazilian children. Classic aEPEC strains were more frequently found in children with diarrhea than in controls (P < 0.001), showing their importance as acute diarrhea agents in our country. Only aEPEC strains carrying either the ehxA or paa gene were significantly associated with diarrhea. PMID:19759223

Scaletsky, Isabel C. A.; Aranda, Katia R. S.; Souza, Tamara B.; Silva, Neusa P.; Morais, Mauro B.

2009-01-01

376

Survival and Plasmid Transfer Ability of Escherichia Coli in Wastewater  

Microsoft Academic Search

No differences were observed in the survival of plasmid-bearingand plasmid-free Escherichia coli strains in the course of a long-term survival process in wastewater, under both illuminated and non-illuminated conditions. While the CFU counts and the number of active cells decreased, the numberof nucleoid-containing cells remained constant throughout the 30 days of experimentation. Visible light efficiently contributed to the reduction in

I. Arana; J. I. Justo; A. Muela; I. Barcina

2001-01-01

377

Electric field induced bacterial flocculation of Enteroaggregative Escherichia coli 042  

SciTech Connect

A response of the aggregation dynamics of enteroaggregative Escherichia coli under low magnitude steady and oscillating electric fields is presented. The presence of uniform electric fields hampered microbial adhesion and biofilm formation on a transverse glass surface, but instead promoted the formation of flocs. Extremely heterogeneous distribution of live and dead cells was observed among the flocs. Moreover, floc formation was largely observed to be independent of the frequency of alternating electric fields.

Kumar, Aloke [ORNL; Mortensen, Ninell P [ORNL; Mukherjee, Partha P [ORNL; Retterer, Scott T [ORNL; Doktycz, Mitchel John [ORNL

2011-01-01

378

Nucleoids Dynamic in Escherichia coli: A Growth Phase Dependent Process  

Microsoft Academic Search

Bacterial DNA compacts in nucleoid bodies. The organization of nucleoid body depends on the association of genomic DNA with a numbers of histone-like proteins. The relax nucleoids organization in rapidly growing Escherichia coli cells associate with six major proteins, Fis, HU, Hfq, H-NS, StpA and IHF, but at stationary phase the nucleoids further tightly pack with Dps. The final steps

Ali Azam Talukder; M Anwar Hossain; Mamoru Yamada; Akira Ishihama

2006-01-01

379

Occurrence of Escherichia coli in Wild Cottontail Rabbits.  

PubMed

Free-ranging cottontail rabbits (Sylvilagus floridanus) from two areas in central Pennsylvania were sampled over a 4-year period. Large numbers of coliforms were isolated from the intestinal tracts of these animals; in 136 of the 141 rabbits sampled, Escherichia coli was found to be a major component of the alimentary flora. Four serogroups (O7, O77, O73, and O103) were predominant among the isolates and were considered resistant coliflora of this species of cottontail rabbit. PMID:16345208

Kozlowski, R; Glantz, P J; Anthony, R G

1977-03-01

380

Functional requirements for heat induced genome amplification in Escherichia coli  

Microsoft Academic Search

A temperature shift-up induces extra rounds of fully replicated chromosomes in Escherichia coli and leads to an increase in DNA\\/mass ratio. In the present work we characterize the requirements for this heat-induced replication (HIR) with respect to replisome components, replication restart, and recombination functions. We found that HIR requires Klenow and 5?–3? exonuclease activities from Pol I and Pol III,

Rocío González-Soltero; Alfonso Jiménez-Sánchez; Emilia Botello

2008-01-01

381

Peroxidase activity of cytochrome bd from Escherichia coli  

Microsoft Academic Search

Cytochrome bd from Escherichia coli is able to oxidize such substrates as guaiacol, ferrocene, benzohydroquinone, and potassium ferrocyanide through the peroxidase\\u000a mechanism, while none of these donors is oxidized in the oxidase reaction (i.e. in the reaction that involves molecular oxygen\\u000a as the electron acceptor). Peroxidation of guaiacol has been studied in detail. The dependence of the rate of the

V. B. Borisov; A. I. Davletshin; A. A. Konstantinov

2010-01-01

382

Expression of fully functional tetrameric human hemoglobin in Escherichia coli  

Microsoft Academic Search

Synthesis genes encoding the human α- and β-globin polypeptides have been expressed from a single operon in Escherichia coli. The α- and β-globin polypeptides associate into soluble tetramers, incorporate heme, and accumulate to >5% of the total cellular protein. Purified recombinant hemoglobin has the correct stoichiometry of α- and β-globin chains and contains a full complement of heme. Each globin

S. J. Hoffman; D. L. Looker; J. M. Roehrich; P. E. Cozart; S. L. Durfee; J. L. Tedesco; G. L. Stetler

1990-01-01

383

Expression of Fully Functional Tetrameric Human Hemoglobin in Escherichia coli  

Microsoft Academic Search

Synthetic genes encoding the human alpha- and beta-globin polypeptides have been expressed from a single operon in Escherichia coli. The alpha- and beta-globin polypeptides associate into soluble tetramers, incorporate heme, and accumulate to >5% of the total cellular protein. Purified recombinant hemoglobin has the correct stoichiometry of alpha- and beta-globin chains and contains a full complement of heme. Each globin

Stephen J. Hoffman; Douglas L. Looker; Jeanne M. Roehrich; Paul E. Cozart; Steven L. Durfee; John L. Tedesco; Gary L. Stetler

1990-01-01

384

Genome sequence of enterohaemorrhagic Escherichia coli O157:H7  

Microsoft Academic Search

The bacterium Escherichia coli O157:H7 is a worldwide threat to public health and has been implicated in many outbreaks of haemorrhagic colitis, some of which included fatalities caused by haemolytic uraemic syndrome. Close to 75,000 cases of O157:H7 infection are now estimated to occur annually in the United States. The severity of disease, the lack of effective treatment and the

Nicole T. Perna; Guy Plunkett; Valerie Burland; Bob Mau; Jeremy D. Glasner; Debra J. Rose; George F. Mayhew; Peter S. Evans; Jason Gregor; Heather A. Kirkpatrick; György Pósfai; Jeremiah Hackett; Sara Klink; Adam Boutin; Ying Shao; Leslie Miller; Erik J. Grotbeck; N. Wayne Davis; Alex Lim; Eileen T. Dimalanta; Konstantinos D. Potamousis; Jennifer Apodaca; Thomas S. Anantharaman; Jieyi Lin; Galex Yen; David C. Schwartz; Rodney A. Welch; Frederick R. Blattner

2001-01-01

385

Recombinant expression of bioactive peptide lunasin in Escherichia coli  

Microsoft Academic Search

Lunasin, a cancer-preventive peptide, was isolated from soybean, barley, and wheat. Previous studies showed that this 43-amino\\u000a acid peptide has the ability to suppress chemical carcinogen-induced transformation in mammalian cells and skin carcinogenesis\\u000a in mice. In this study, we attempted to use the Escherichia coli T7 expression system for expression of lunasin. The lunasin gene was synthesized by overlapping extension

Chin-Feng Liu; Tzu-Ming Pan

2010-01-01

386

Lethal Effects of Electric Current on Escherichia coli  

PubMed Central

An attempt has been made to use low-voltage alternating current to kill microorganisms such as Escherichia coli. The bactericidal effect depends on the energy passing through the suspension and on the time during which the cells are left standing in the medium after the treatment. Most of the toxicity is due to an indirect effect developed with unalterable electrodes in the presence of chlorides in the medium. This method might be applied to eliminate pollution of natural waters. PMID:4909349

Pareilleux, A.; Sicard, N.

1970-01-01

387

Avian pathogenic Escherichia coli bind fibronectin and laminin  

Microsoft Academic Search

Avian colisepticemia frequently occurs after respiratory tract damage, the primary site for infection allows bacteria to encounter\\u000a an exposed basement membrane, where laminin and fibronectin are important components. We investigated the ability of an isolate\\u000a of avian pathogenic Escherichia coli to bind fibronectin and laminin. Using Far-western dot blot analysis, we demonstrated the ability of this microorganism to\\u000a bind basement

Rosa María Ramírez; Yolanda Almanza; Rafael González; Santos García; Norma Heredia

2009-01-01

388

Chemotaxis in Escherichia coli: Methylation of che Gene Products  

Microsoft Academic Search

The products of three chemotaxis-specific genes in Escherichia coli, cheM, cheD, and cheZ, are methylated. The cheZ gene codes for the synthesis of a 24,000 molecular weight polypeptide that appears in the cytoplasm. cheM codes for the synthesis of a membrane-bound polypeptide with a molecular weight of 61,000. cheD codes for another membrane-bound polypeptide with an apparent molecular weight of

Michael Silverman; Melvin Simon

1977-01-01

389

A second allosteric site in Escherichia coli aspartate transcarbamoylase.  

PubMed

Escherichia coli aspartate transcarbamoylase is feedback inhibited by CTP and UTP in the presence of CTP. Here, we show by X-ray crystallography that UTP binds to a unique site on each regulatory chain of the enzyme that is near but not overlapping with the known CTP site. These results bring into question all of the previously proposed mechanisms of allosteric regulation in aspartate transcarbamoylase. PMID:22667327

Peterson, Alexis W; Cockrell, Gregory M; Kantrowitz, Evan R

2012-06-19

390

Ozone-initiated disinfection kinetics of Escherichia coli in water  

Microsoft Academic Search

The effect of ozonation on the rate of disinfection of Escherichia coli was investigated as a function of ozone concentration, ozonation duration and flow rates. Ozone was generated in situ using Corona discharge method using compressed oxygen stream and depending on the oxygen flux the ozone concentrations ranged from 0.91–4.72 mg\\/L. The rate of disinfection of all the three microbes

Favourite Zuma; Johnson Lin; Sreekanth B. Jonnalagadda

2009-01-01

391

Biomolecular Mechanisms of Pseudomonas aeruginosa and Escherichia coli Biofilm Formation  

PubMed Central

Pseudomonas aeruginosa and Escherichia coli are the most prevalent Gram-negative biofilm forming medical device associated pathogens, particularly with respect to catheter associated urinary tract infections. In a similar manner to Gram-positive bacteria, Gram-negative biofilm formation is fundamentally determined by a series of steps outlined more fully in this review, namely adhesion, cellular aggregation, and the production of an extracellular polymeric matrix. More specifically this review will explore the biosynthesis and role of pili and flagella in Gram-negative adhesion and accumulation on surfaces in Pseudomonas aeruginosa and Escherichia coli. The process of biofilm maturation is compared and contrasted in both species, namely the production of the exopolysaccharides via the polysaccharide synthesis locus (Psl), pellicle Formation (Pel) and alginic acid synthesis in Pseudomonas aeruginosa, and UDP-4-amino-4-deoxy-l-arabinose and colonic acid synthesis in Escherichia coli. An emphasis is placed on the importance of the LuxR homologue sdiA; the luxS/autoinducer-II; an autoinducer-III/epinephrine/norepinephrine and indole mediated Quorum sensing systems in enabling Gram-negative bacteria to adapt to their environments. The majority of Gram-negative biofilms consist of polysaccharides of a simple sugar structure (either homo- or heteropolysaccharides) that provide an optimum environment for the survival and maturation of bacteria, allowing them to display increased resistance to antibiotics and predation.

Laverty, Garry; Gorman, Sean P.; Gilmore, Brendan F.

2014-01-01

392

Analysis of plasmids cloned from a virulent avian Escherichia coli and transformed into Escherichia coli DH5 alpha.  

PubMed

Three of four plasmids from a virulent wild-type avian Escherichia coli were cloned or transformed into an avirulent laboratory recipient E. coli DH5 alpha and tested for the ability to confer a virulence phenotype. The three plasmids transformed into E. coli DH5 alpha were 5, 6, and 56 kb. A fourth plasmid of 64 kb was not successfully transformed. Parameters used to measure virulence included presence of type 1 pili and a smooth lipopolysaccharide (LPS) layer, motility, production of Colicin V, resistance to host complement, and embryo lethality. The 5-kb plasmid encoded for ampicillin resistance, whereas the 6-kb plasmid encoded for tetracycline resistance. The 56-kb plasmid encoded for streptomycin, sulfisoxazole, and tetracycline resistance. Twelve-day embryos inoculated with 467 colony-forming units of E. coli DH5 alpha containing the 56-kb plasmid had increased death rates (45%) in the embryo lethality assay and a decreased weight of surviving embryos with cranial hemorrhages as compared with embryos inoculated with similar amounts of E. coli DH5 alpha (0%) and phosphate-buffered saline (0%). Embryos inoculated with the wild-type virulent E. coli had 90% deaths. The 56-kb plasmid also had homology with a probe for Colicin V production (cvaC). No differences in LPS layer, complement resistance, motility, Colicin V activity, type 1 pili, cell-free supernatant proteins, or outer membrane proteins were observed in the transformants when compared with nontransformed E. coli DH5 alpha. PMID:8883780

Wooley, R E; Gibbs, P S; Dickerson, H W; Brown, J; Nolan, L K

1996-01-01

393

Transduction of Escherichia coli by bacteriophage P1 in soil.  

PubMed Central

Transduction of Escherichia coli W3110(R702) and J53(RP4) (10(4) to 10(5) CFU/g of soil) by lysates of temperature-sensitive specialized transducing derivatives of bacteriophage P1 (10(4) to 10(5) PFU/g of soil) (P1 Cm cts, containing the resistance gene for chloramphenicol, or P1 Cm cts::Tn501, containing the resistance genes for chloramphenicol and mercury [Hg]) occurred in soil amended with montmorillonite or kaolinite and adjusted to a -33-kPa water tension. In nonsterile soil, survival of introduced E. coli and the numbers of E. coli transductants resistant to chloramphenicol or Hg were independent of the clay amendment. The numbers of added E. coli increased more when bacteria were added in Luria broth amended with Ca and Mg (LCB) than when they were added in saline, and E. coli transductants were approximately 1 order of magnitude higher in LCB; however, the same proportion of E. coli was transduced with both types of inoculum. In sterile soil, total and transduced E. coli and P1 increased by 3 to 4 logs, which was followed by a plateau when they were inoculated in LCB and a gradual decrease when they were inoculated in saline. Transduction appeared to occur primarily in the first few days after addition of P1 to soil. The transfer of Hg or chloramphenicol resistance from lysogenic to nonlysogenic E. coli by phage P1 occurred in both sterile and nonsterile soils. On the basis of heat-induced lysis and phenotype, as well as hybridization with a DNA probe in some studies, the transductants appeared to be the E. coli that was added. Transduction of indigenous soil bacteria was not unequivocally demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3046491

Zeph, L R; Onaga, M A; Stotzky, G

1988-01-01

394

Fluorogenic assays for immediate confirmation of Escherichia coli.  

PubMed Central

Rapid assays for Escherichia coli were developed by using the compound 4-methylumbelliferone glucuronide (MUG), which is hydrolyzed by glucuronidase to yield a fluorogenic product. The production of glucuronidase was limited to strains of E. coli and some Salmonella and Shigella strains in the family Enterobacteriaceae. For immediate confirmation of the presence of E. coli in most-probable-number tubes, MUG was incorporated into lauryl tryptose broth at a final concentration of 100 micrograms/ml. Results of both the presumptive test (gas production) and the confirmed test (fluorescence) for E. coli were obtained from a variety of food, water, and milk samples after incubation for only 24 h at 35 degrees C. Approximately 90% of the tubes showing both gas production and fluorescence contained fecal coliforms (they were positive in EC broth incubated at 45 degrees C). Few false-positive reactions were observed. The lauryl tryptose broth-MUG-most-probable-number assay was superior to violet red bile agar for the detection of heat- and chlorine-injured E. coli cells. Anaerogenic strains produced positive reactions, and small numbers of E. coli could be detected in the presence of large numbers of competing bacteria. The fluorogenic assay was sensitive and rapid; the presence of one viable cell was detected within 20 h. E. coli colonies could be distinguished from other coliforms on membrane filters and plates of violet red bile agar if MUG was incorporated into the culture media. A rapid confirmatory test for E. coli that is amenable to automation was developed by using microtitration plates filled with a nonselective medium containing MUG. Pure or mixed cultures containing E. coli produced fluorescence within 4 h (most strains) to 24 h (a few weakly positive strains). Images PMID:7049088

Feng, P C; Hartman, P A

1982-01-01

395

Chapter 8 Isolation and Identification of Escherichia coli  

E-print Network

Isolation and identification of Escherichia coli serotype O157:H7 can be greatly enhanced when optimal laboratory media and techniques are employed. The methods presented here are intended to be economical and to offer laboratorians some flexibility in choice of protocol and media. Laboratories that do not have sufficient resources to adopt the methods described below should consider sending specimens or isolates to other laboratory facilities that routinely perform these procedures. Laboratory supplies required for diagnosis of E. coli O157:H7 are listed in Annex H. A. Isolation and Identification Methods E. coli O157:H7 rapidly ferments lactose and is indistinguishable from most other E. coli serotypes on traditional lactose-containing media. However, unlike approximately 80 % of other E. coli, nearly all isolates of E. coli O157:H7 ferment D-sorbitol slowly, or not at all. Sorbitol-MacConkey (SMAC) agar was developed to take advantage of this characteristic by substituting the carbohydrate sorbitol for lactose in MacConkey agar, and it is the medium of choice for

unknown authors

396

Direct transmission of Escherichia coli from poultry to humans.  

PubMed Central

Eight hundred and sixty-four Escherichia coli isolates from workers at the University of Ibadan Teaching and Research Poultry Farm, and 216 isolates from poultry attendants at a commercial poultry farm in the city were found to be resistant to streptomycin, sulphafurazole and tetracycline. In contrast, all 576 and 288 E. coli isolates from village fowls and from villagers respectively were sensitive to these drugs. Isolates from birds in a modern university poultry unit (3744) exhibited the same resistance patterns as those isolated from workers who were in direct contact with the birds. No nalidixic acid-resistant E. coli was isolated from farm workers prior to their assignment to the experimental pen. Following experimental oral infection of birds with E. coli K12 J5 NA+ Lac-, the organism was recovered from the workers who manned the experimental pen. Neither before nor after the experimental infection was any nalidixic acid-resistant E. coli isolated from workers who manned the pen from which birds used in the experiment were selected. Similarly, no drug resistant organisms were isolated from workers outside the poultry unit of the university or commercial farm. The MIC of the drugs against the avian and human E. coli isolates at the university and commercial poultry farms were similar. PMID:2691268

Ojeniyi, A. A.

1989-01-01

397

Escherichia coli Isolated from Domestic Animals Pathogenic for Gnotobiotic Piglets.  

PubMed

Three strains of Escherichia coli isolated from infectious processes in a calf, a dog, and a cat were examined for their capacity to produce disease or death, or both, in newborn gnotobiotic piglets. The O groups represented by these particular strains of E. coli were O4: (canine origin), O6: (feline origin), and O39: (bovine origin). All three isolates upon oral administration proved to be pathogenic. Infection with the E. coli O4: (canine) or O39: (bovine) consistently produced signs of enteric coli-bacillosis and death in all 1- and 3-day-old piglets within 24 to 48 hr. The O6: (feline) isolate, on the other hand, produced a marked polyserositis and generally required 6 to 7 days to kill a piglet. Only the respective type of E. coli used in the particular trial was recovered from the diseased piglets. These findings suggest the possible role of domestic animals and household pets in the spread of potentially pathogenic E. coli to other species. PMID:16558047

Meyer, R C; Rhoades, H E; Saxena, S P; Simon, J

1971-06-01

398

Escherichia coli sequence type 131: epidemiology and challenges in treatment.  

PubMed

Escherichia coli ST131 has emerged as a global epidemic, multidrug-resistant clone of E. coli causing extra-intestinal infections. It is now highly prevalent among fluoroquinolone-resistant and CTX-M ESBL-producing E. coli isolates worldwide. Humans are likely the primary reservoir of ST131. Factors associated with its acquisition include residence in long-term care facilities and recent receipt of antimicrobial agents. E. coli ST131 causes a wide array of infections ranging from cystitis to life-threatening sepsis. Fluoroquinolones and trimethoprim-sulfamethoxazole are no longer adequate options for empiric therapy when E. coli ST131 is suspected from risk factors and local epidemiology. Expanded-spectrum cephalosporins, piperacillin-tazobactam and carbapenems are options to treat serious non-ESBL-producing E. coli ST131 infections, while carbapenems are indicated for ESBL-producing infections. There is a growing interest in reevaluating oral agents including fosfomycin and pivmecillinam for less serious infections such as uncomplicated cystitis. PMID:24694052

Qureshi, Zubair A; Doi, Yohei

2014-05-01

399

Fitness of Escherichia coli during Urinary Tract Infection Requires Gluconeogenesis and the TCA Cycle  

PubMed Central

Microbial pathogenesis studies traditionally encompass dissection of virulence properties such as the bacterium's ability to elaborate toxins, adhere to and invade host cells, cause tissue damage, or otherwise disrupt normal host immune and cellular functions. In contrast, bacterial metabolism during infection has only been recently appreciated to contribute to persistence as much as their virulence properties. In this study, we used comparative proteomics to investigate the expression of uropathogenic Escherichia coli (UPEC) cytoplasmic proteins during growth in the urinary tract environment and systematic disruption of central metabolic pathways to better understand bacterial metabolism during infection. Using two-dimensional fluorescence difference in gel electrophoresis (2D-DIGE) and tandem mass spectrometry, it was found that UPEC differentially expresses 84 cytoplasmic proteins between growth in LB medium and growth in human urine (P<0.005). Proteins induced during growth in urine included those involved in the import of short peptides and enzymes required for the transport and catabolism of sialic acid, gluconate, and the pentose sugars xylose and arabinose. Proteins required for the biosynthesis of arginine and serine along with the enzyme agmatinase that is used to produce the polyamine putrescine were also up-regulated in urine. To complement these data, we constructed mutants in these genes and created mutants defective in each central metabolic pathway and tested the relative fitness of these UPEC mutants in vivo in an infection model. Import of peptides, gluconeogenesis, and the tricarboxylic acid cycle are required for E. coli fitness during urinary tract infection while glycolysis, both the non-oxidative and oxidative branches of the pentose phosphate pathway, and the Entner-Doudoroff pathway were dispensable in vivo. These findings suggest that peptides and amino acids are the primary carbon source for E. coli during infection of the urinary tract. Because anaplerosis, or using central pathways to replenish metabolic intermediates, is required for UPEC fitness in vivo, we propose that central metabolic pathways of bacteria could be considered critical components of virulence for pathogenic microbes. PMID:19478872

Alteri, Christopher J.; Smith, Sara N.; Mobley, Harry L. T.

2009-01-01

400

[Escherichia coli, a pathogen under fire from the news].  

PubMed

Escherichia coli is both a gastrointestinal tract commensal and a major pathogen. In recent years, E. coli is under fire from the news due to a better understanding of pathogenic factors, outbreaks of infections caused by enterohaemorrhagic strains, and last but not least, the worrying development of antibiotic resistance. Due to the absence of new compounds active against these strains, producing extended-spectrum ß-lactamases (ESBL) and frequently multiresistant to other antibiotics, their emergence will pose therapeutic problems for practitioners of all pediatric specialties. The gold standard treatment for severe infections due to ESBL-E. coli family is the penem class. The frequent use of penems promotes the emergence of strains resistant to carbapenems. Sparing carbapenems should be a clear objective for non life-threatening infections. PMID:23178139

Cohen, R; Raymond, J; Gendrel, D; Bingen, E

2012-11-01

401

Inhibition of injured Escherichia coli by several selective agents.  

PubMed

A population of Escherichia coli ML30 cells was exposed to a quaternary ammonium compound, and injury to the cells was measured by a comparison of counts on Trypticase Soy Agar and Violet Red Bile Agar. Substantial injury could not be detected with a minimal medium. The ingredients of Violet Red Bile Agar were tested against damaged cells. The bile salts mixture alone in the medium prevented as many injured cells from growing as did any combination of the selective agents and inhibited as many injured bacteria as were inhibited by Violet Red Bile Agar itself. These dyes and salts were similarly assayed in minimal agar, and comparable results were obtained. Individual bile salts and other potential selective agents were added to the minimal medium, and the media were tested for inhibition of injured E. coli. Sodium deoxycholate was the bile salt most inhibitory to damaged E. coli cells. PMID:4924998

Scheusner, D L; Busta, F F; Speck, M L

1971-01-01

402

Engineering Escherichia coli K12 MG1655 to use starch  

PubMed Central

Background To attain a sustainable bioeconomy, fuel, or valuable product, production must use biomass as substrate. Starch is one of the most abundant biomass resources and is present as waste or as a food and agroindustry by-product. Unfortunately, Escherichia coli, one of the most widely used microorganisms in biotechnological processes, cannot use starch as a carbon source. Results We engineered an E. coli strain capable of using starch as a substrate. The genetic design employed the native capability of the bacterium to use maltodextrins as a carbon source plus expression and secretion of its endogenous ?-amylase, AmyA, in an adapted background. Biomass production improved using 35% dissolved oxygen and pH 7.2 in a controlled bioreactor. Conclusion The engineered E. coli strain can use starch from the milieu and open the possibility of optimize the process to use agroindustrial wastes to produce biofuels and other valuable chemicals. PMID:24886307

2014-01-01

403

???????????????????????????????????????????????????????????????? Escherichia coli ????????????????????????? ISOLATION AND SCREENING OF LACTIC ACID BACTERIA CAPABLE OF INHIBITING GROWTH OF SOME ESCHERICHIA COLI ISOLATED FROM SWINE  

Microsoft Academic Search

One hundred and forty-seven strains of lactic acid bacteria (LAB) were isolated from some soils, fermented foods, vegetables, fruits, milk and animal products. After cultivation in MRS broth at 37 ?C for 96 hours, each culture supernatant was evaluated its growth inhibitory activity by using a paper disc diffusion method against one strain of Escherichia coli O157:H7 and nine strains

Mongkhon Punyarat; Narumol Thongwai

404

ESCHERICHIA COLI ISOLATED FROM CALVES WITH DIARRHŒA: MANNOSE-RESISTANT HAEMAGGLUTINATION  

E-print Network

ESCHERICHIA COLI ISOLATED FROM CALVES WITH DIARRHŒA: MANNOSE-RESISTANT HAEMAGGLUTINATION souches de Escherichia coli isolées des veaux diarrhéiques. La détection de l'antigène K99, en 84 souches de Escherichia coli, a été effectuée par le Brush-Border, l'hémagglutination avec et sans mannose et

Paris-Sud XI, Université de

405

Domain Bridging Interactions in the Allosteric Network for IIAGlc Inhibition of the Escherichia coli Glycerol Kinase  

E-print Network

DOMAIN BRIDGING INTERACTIONS IN THE ALLOSTERIC NETWORK FOR IIAGLC INHIBITION OF THE ESCHERICHIA COLI GLYCEROL KINASE A Thesis by EDITH ABENA ACQUAYE Submitted to the Office of Graduate Studies of Texas A&M University... of the Escherichia coli Glycerol Kinase Copyright 2010 Edith Abena Acquaye DOMAIN BRIDGING INTERACTIONS IN THE ALLOSTERIC NETWORK FOR IIAGLC INHIBITION OF THE ESCHERICHIA COLI GLYCEROL KINASE A Thesis by EDITH ABENA ACQUAYE Submitted...

Acquaye, Edith Abena

2011-10-21

406

Global dissemination of a multidrug resistant Escherichia coli clone  

PubMed Central

Escherichia coli sequence type 131 (ST131) is a globally disseminated, multidrug resistant (MDR) 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 several factors, including resistance to fluoroquinolones, high virulence gene content, the possession of the type 1 fimbriae FimH30 allele, and the production of the CTX-M-15 extended spectrum ?-lactamase (ESBL). Here, we used genome sequencing to examine the molecular epidemiology of a collection of E. coli ST131 strains isolated from six distinct geographical locations across the world spanning 2000–2011. The global phylogeny of E. coli ST131, determined from whole-genome sequence data, revealed a single lineage of E. coli ST131 distinct from other extraintestinal E. coli strains within the B2 phylogroup. Three closely related E. coli ST131 sublineages were identified, with little association to geographic origin. The majority of single-nucleotide variants associated with each of the sublineages were due to recombination in regions adjacent to mobile genetic elements (MGEs). The most prevalent sublineage of ST131 strains was characterized by fluoroquinolone resistance, and a distinct virulence factor and MGE profile. Four different variants of the CTX-M ESBL–resistance gene were identified in our ST131 strains, with acquisition of CTX-M-15 representing a defining feature of a discrete but geographically dispersed ST131 sublineage. This study confirms the global dispersal of a single E. coli ST131 clone and demonstrates the role of MGEs and recombination in the evolution of this important MDR pathogen. PMID:24706808

Petty, Nicola K.; Ben Zakour, Nouri L.; Stanton-Cook, Mitchell; Skippington, Elizabeth; Totsika, Makrina; Forde, Brian M.; Phan, Minh-Duy; Gomes Moriel, Danilo; Peters, Kate M.; Davies, Mark; Rogers, Benjamin A.; Dougan, Gordon; Rodriguez-Bano, Jesus; Pascual, Alvaro; Pitout, Johann D. D.; Upton, Mathew; Paterson, David L.; Walsh, Timothy R.; Schembri, Mark A.; Beatson, Scott A.

2014-01-01

407

Discovery of Escherichia coli methionyl-tRNA synthetase mutants for efficient labeling of proteins  

E-print Network

Discovery of Escherichia coli methionyl-tRNA synthetase mutants for efficient labeling of proteins with mutant forms of MetRS. Link and coworkers recently reported a high-throughput screen for E. coli Met

Goddard III, William A.

408

Autoinducer 2-based quorum sensing response of Escherichia coli to sub-therapeutic tetracycline exposure  

E-print Network

-therapeutic tetracycline, the expression of genes associated with the conjugal transfer of antibiotic resistance plasmids, and the conjugal transfer of these plasmids in Escherichia coli. The studies showed that AI-2 activity increased in Tets E. coli in the presence...

Lu, Lingeng

2006-10-30

409

THE WIDESPREAD OCCURRENCE OF THE ENTEROHEMOLYSIN GENE EHLYA AMONG ENVIRONMENTAL STRAINS OF ESCHERICHIA COLI  

EPA Science Inventory

The putative virulence factor enterohemolysin, encoded for by the ehlyA gene, has been closely associated with the pathogenic enterohemorrhagic Escherichia coli (EHEC) group. E. coli isolates from effluents from seven geographically dispersed municipal ...

410

Salmonella typhimurium intercepts Escherichia coli signaling to enhance antibiotic tolerance  

PubMed Central

Bacterial communication plays an important role in many population-based phenotypes and interspecies interactions, including those in host environments. These interspecies interactions may prove critical to some infectious diseases, and it follows that communication between pathogenic bacteria and commensal bacteria is a subject of growing interest. Recent studies have shown that Escherichia coli uses the signaling molecule indole to increase antibiotic tolerance throughout its population. Here, we show that the intestinal pathogen Salmonella typhimurium increases its antibiotic tolerance in response to indole, even though S. typhimurium does not natively produce indole. Increased antibiotic tolerance can be induced in S. typhimurium by both exogenous indole added to clonal S. typhimurium populations and indole produced by E. coli in mixed-microbial communities. Our data show that indole-induced tolerance in S. typhimurium is mediated primarily by the oxidative stress response and, to a lesser extent, by the phage shock response, which were previously shown to mediate indole-induced tolerance in E. coli. Further, we find that indole signaling by E. coli induces S. typhimurium antibiotic tolerance in a Caenorhabditis elegans model for gastrointestinal infection. These results suggest that the intestinal pathogen S. typhimurium can intercept indole signaling from the commensal bacterium E. coli to enhance its antibiotic tolerance in the host intestine. PMID:23946425

Vega, Nicole M.; Allison, Kyle R.; Samuels, Amanda N.; Klempner, Mark S.; Collins, James J.

2013-01-01

411

The genetic basis of Escherichia coli pathoadaptation to macrophages.  

PubMed

Antagonistic interactions are likely important driving forces of the evolutionary process underlying bacterial genome complexity and diversity. We hypothesized that the ability of evolved bacteria to escape specific components of host innate immunity, such as phagocytosis and killing by macrophages (M?), is a critical trait relevant in the acquisition of bacterial virulence. Here, we used a combination of experimental evolution, phenotypic characterization, genome sequencing and mathematical modeling to address how fast, and through how many adaptive steps, a commensal Escherichia coli (E. coli) acquire this virulence trait. We show that when maintained in vitro under the selective pressure of host M? commensal E. coli can evolve, in less than 500 generations, virulent clones that escape phagocytosis and M? killing in vitro, while increasing their pathogenicity in vivo, as assessed in mice. This pathoadaptive process is driven by a mechanism involving the insertion of a single transposable element into the promoter region of the E. coli yrfF gene. Moreover, transposition of the IS186 element into the promoter of Lon gene, encoding an ATP-dependent serine protease, is likely to accelerate this pathoadaptive process. Competition between clones carrying distinct beneficial mutations dominates the dynamics of the pathoadaptive process, as suggested from a mathematical model, which reproduces the observed experimental dynamics of E. coli evolution towards virulence. In conclusion, we reveal a molecular mechanism explaining how a specific component of host innate immunity can modulate microbial evolution towards pathogenicity. PMID:24348252

Miskinyte, Migla; Sousa, Ana; Ramiro, Ricardo S; de Sousa, Jorge A Moura; Kotlinowski, Jerzy; Caramalho, Iris; Magalhães, Sara; Soares, Miguel P; Gordo, Isabel

2013-01-01

412

The Escherichia coli Proteome: Past, Present, and Future Prospects†  

PubMed Central

Proteomics has emerged as an indispensable methodology for large-scale protein analysis in functional genomics. The Escherichia coli proteome has been extensively studied and is well defined in terms of biochemical, biological, and biotechnological data. Even before the entire E. coli proteome was fully elucidated, the largest available data set had been integrated to decipher regulatory circuits and metabolic pathways, providing valuable insights into global cellular physiology and the development of metabolic and cellular engineering strategies. With the recent advent of advanced proteomic technologies, the E. coli proteome has been used for the validation of new technologies and methodologies such as sample prefractionation, protein enrichment, two-dimensional gel electrophoresis, protein detection, mass spectrometry (MS), combinatorial assays with n-dimensional chromatographies and MS, and image analysis software. These important technologies will not only provide a great amount of additional information on the E. coli proteome but also synergistically contribute to other proteomic studies. Here, we review the past development and current status of E. coli proteome research in terms of its biological, biotechnological, and methodological significance and suggest future prospects. PMID:16760308

Han, Mee-Jung; Lee, Sang Yup

2006-01-01

413

Nonthermal atmospheric argon plasma jet effects on Escherichia coli biomacromolecules.  

PubMed

Nonthermal atmospheric plasma jet, a promising technology based on ionized gas at low temperatures, can be applied for disinfection of contaminated surfaces. In this study, Escherichia coli cells and their macromolecules were exposed to the nonthermal atmospheric argon plasma jet for different time durations. Total protein, genomic DNA, and malondialdehyde (MDA) levels of E. coli were assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining; agarose gel electrophoresis; and measurement of absorbance at 534 nm, respectively. After exposure, the spectroscopic results of liquid samples indicated that the survival reduction of E. coli can reach to 100 % in an exposure time of 600 s. Moreover, inactivation zones of E. coli, DNA degradation, and MDA levels were significantly increased. Additionally, banding patterns of total protein were changed and amino acid concentrations increased following ninhydrin test. The experimental results suggest that the nonthermal plasma could serve as an effective instrument for both sterilizing E. coli and degrading macromolecules from the surface of the objects being sterilized. PMID:23982422

Hosseinzadeh Colagar, Abasalt; Memariani, Hamed; Sohbatzadeh, Farshad; Valinataj Omran, Azadeh

2013-12-01

414

Recent Advances in Understanding Enteric Pathogenic Escherichia coli  

PubMed Central

SUMMARY Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli (pathovars or pathotypes) cause much morbidity and mortality worldwide. Consequently, pathogenic E. coli is widely studied in humans, animals, food, and the environment. While there are many common features that these pathotypes employ to colonize the intestinal mucosa and cause disease, the course, onset, and complications vary significantly. Outbreaks are common in developed and developing countries, and they sometimes have fatal consequences. Many of these pathotypes are a major public health concern as they have low infectious doses and are transmitted through ubiquitous mediums, including food and water. The seriousness of pathogenic E. coli is exemplified by dedicated national and international surveillance programs that monitor and track outbreaks; unfortunately, this surveillance is often lacking in developing countries. While not all pathotypes carry the same public health profile, they all carry an enormous potential to cause disease and continue to present challenges to human health. This comprehensive review highlights recent advances in our understanding of the intestinal pathotypes of E. coli. PMID:24092857

Croxen, Matthew A.; Law, Robyn J.; Scholz, Roland; Keeney, Kristie M.; Wlodarska, Marta

2013-01-01

415

Glucosylation of Isoflavonoids in Engineered Escherichia coli  

PubMed Central

A glycosyltransferase, YjiC, from Bacillus licheniformis has been used for the modification of the commercially available isoflavonoids genistein, daidzein, biochanin A and formononetin. The in vitro glycosylation reaction, using UDP-?-D-glucose as a donor for the glucose moiety and aforementioned four acceptor molecules, showed the prominent glycosylation at 4? and 7 hydroxyl groups, but not at the 5th hydroxyl group of the A-ring, resulting in the production of genistein 4?-O-?-D-glucoside, genistein 7-O-?-D-glucoside (genistin), genistein 4?,7-O-?-D-diglucoside, biochanin A-7-O-?-D-glucoside (sissotrin), daidzein 4?-O-?-D-glucoside, daidzein 7-O-?-D-glucoside (daidzin), daidzein 4?, 7-O-?-D-diglucoside, and formononetin 7-O-?-D-glucoside (ononin). The structures of all the products were elucidated using high performance liquid chromatography-photo diode array and high resolution quadrupole time-of-flight electrospray ionization mass spectrometry (HR QTOFESI/MS) analysis, and were compared with commercially available standard compounds. Significantly higher bioconversion rates of all four isoflavonoids was observed in both in vitro as well as in vivo bioconversion reactions. The in vivo fermentation of the isoflavonoids by applying engineered E. coli BL21(DE3)/?pgi?zwf?ushA overexpressing phosphoglucomutase (pgm) and glucose 1-phosphate uridyltransferase (galU), along with YjiC, found more than 60% average conversion of 200 ?M of supplemented isoflavonoids, without any additional UDP-?-D-glucose added in fermentation medium, which could be very beneficial to large scale industrial production of isoflavonoid glucosides. PMID:24599002

Pandey, Ramesh Prasad; Parajuli, Prakash; Koirala, Niranjan; Lee, Joo Ho; Park, Yong Il; Sohng, Jae Kyung

2014-01-01

416

FRQUENCE DU ROTAVIRUS ET DE L'ASSOCIATION ROTAVIRUS ET ESCHERICHIA COLI K99+  

E-print Network

FR�QUENCE DU ROTAVIRUS ET DE L'ASSOCIATION ROTAVIRUS ET ESCHERICHIA COLI K99+ CHEZ DES VEAUX DE Escherichia coli (E. coli) porteurs de l'antigène K99', chez les veaux atteints de diarrhées néo- natales. coli K99' is found in 5 % of sick animals less than 10 days old. La mise en évidence par microscopie

Boyer, Edmond

417

Killing of Escherichia coli by human polymorphonuclear leucocytes in the presence of Bacteroides fragilis  

Microsoft Academic Search

The inhibitory effect of Bacteroides fragilis on the in vitro killing of Escherichia coli by polymorphonuclear leucocytes was studied with two pairs of E coli and B fragilis isolated from human wound infections. Both B fragilis strains behaved similarly: they inhibited the killing of one E coli strain, while the killing of the other E coli strain was not affected.

W A Vel; F Namavar; A M Verweij-van Vught; A N Pubben; D M MacLaren

1985-01-01

418

Influence of urinary constituents on the adherence of Escherichia coli to human uroepithelial cells in vitro  

Microsoft Academic Search

To study the influence of some urinary constituents on the adhesion ability of Escherichia coli to uroepithelial cells, a standard piliated strain (E. coli 31-B), its mutant lacking in type I pili (E. coli BH-5), and a wild-type laboratory E. coli isolate of serotype 04 possessing both MR and MS pili were used. The average number of bacteria adhering per

Vinod Kumar; Rajeshwar Sharma; Sanjay Chhibber; Kusum Harjai; Saroj Sharma

1997-01-01

419

FRQUENCE DES PILI FY ET K99 PARMI DES SOUCHES DE ESCHERICHIA COLI  

E-print Network

FRÃ?QUENCE DES PILI FY ET K99 PARMI DES SOUCHES DE ESCHERICHIA COLI ISOLÃ?ES DE VEAUX DIARRHÃ?IQUES EN IN FRANCE. - Epidemiological study of bovine E. coli shows that the FY E. coli pilus which has previously, eight of them carrying both FY and K99 pili. The K99 E. coli pilus is present in 86 fecal samples

Boyer, Edmond

420

INFECTION WITH ENTEROTOXIGENIC ESCHERICHIA COLI IN CALVES AND PROTECTION OF THE CALVES  

E-print Network

factors. The microorganisms most commonly incriminated are Escherichia coli (E. coli), rotavirus, coronavirus, and Cryptosporidium. Infection with E. coli in calves manifests itself in at least two different syndromes (Smith and Halls, 1968). One of these is E. coli septicaemia, which occurs in the first week

Paris-Sud XI, Université de

421

The Crystal Structure of the Escherichia coli RNase E Apoprotein and a Mechanism for  

E-print Network

Structure Article The Crystal Structure of the Escherichia coli RNase E Apoprotein and a Mechanism of structured RNA precursors in Escheri- chia coli. Here, we present the crystal structure of the E. coli RNase- radation of most mRNA in E. coli (Mudd et al., 1990; Babitzke and Kushner, 1991). In addition to its purely

Scott, William

422

MECHANISM OF ACTION OF NALIDIXIC ACID ON ESCHERICHIA COLI  

PubMed Central

Goss, William A. (Sterling-Winthrop Research Institute, Rensselaer, N.Y.), William H. Dietz, and Thomas M. Cook. Mechanism of action of nalidixic acid on Escherichia coli. J. Bacteriol. 88:1112–1118. 1964.—Nalidixic acid was lethal for proliferating cultures of Escherichia coli. Associated with this lethal effect was the formation of elongated, serpentine forms. Cultures treated with nalidixic acid were osmotically stable; lethality was observed in the presence of stabilizers. Although it was possible to demonstrate leakage of intracellular components from treated cells, this effect occurred only after 99% of the cells were nonviable. Nalidixic acid had little or no effect on respiration with glucose as substrate. If cellular growth was restricted by suboptimal temperature or nutritional deficiencies, the drug was not lethal. Chemical analysis of cellular constituents revealed that lipid, protein, and ribonucleic acid levels were of the same order of magnitude in control and drug-treated cells. Only deoxyribonucleic acid (DNA) levels were markedly lowered in drug-treated cells. These facts are consistent with the view that nalidixic acid interferes with the synthesis of E. coli DNA. Images PMID:14219026

Goss, William A.; Deitz, William H.; Cook, Thomas M.

1964-01-01

423

Distribution of Core Oligosaccharide Types in Lipopolysaccharides from Escherichia coli  

PubMed Central

In the lipopolysaccharides of Escherichia coli there are five distinct core oligosaccharide (core OS) structures, designated K-12 and R1 to R4. The objective of this work was to determine the prevalences of these core OS types within the species. Unique sequences in the waa (core OS biosynthesis) gene operon were used to develop a PCR-based system that facilitated unequivocal determination of the core OS types in isolates of E. coli. This system was applied to the 72 isolates in the E. coli ECOR collection, a compilation of isolates that is considered to be broadly representative of the genetic diversity of the species. Fifty (69.4%) of the ECOR isolates contained the R1 core OS, 8 (11.1%) were representatives of R2, 8 (11.1%) were R3, 2 (2.8%) were R4, and only 4 (5.6%) were K-12. R1 is the only core OS type found in all four major phylogenetic groups (A, B1, B2, and D) in the ECOR collection. Virulent extraintestinal pathogenic E. coli isolates tend to be closely related to group B2 and, to a lesser extent, group D isolates. All of the ECOR representatives from the B2 and D groups had the R1 core OS. In contrast, commensal E. coli isolates are more closely related to group A, which contains isolates representing each of the five core OS structures. R3 was the only core OS type found in 38 verotoxigenic E. coli (VTEC) isolates from humans and cattle belonging to the common enterohemorrhagic E. coli serogroups O157, O111, and O26. Although isolates from other VTEC serogroups showed more core OS diversity, the R3 type (83.1% of all VTEC isolates) was still predominant. When non-VTEC commensal isolates from cattle were analyzed, it was found that most possessed the R1 core OS type. PMID:10678915

Amor, Karen; Heinrichs, David E.; Frirdich, Emilisa; Ziebell, Kim; Johnson, Roger P.; Whitfield, Chris

2000-01-01

424

Widespread antibiotic resistance of diarrheagenic Escherichia coli and Shigella species  

PubMed Central

Background: Antibiotic resistance of enteric pathogens particularly Shigella species, is a critical world-wide problem and monitoring their resistant pattern is essential, because the choice of antibiotics is absolutely dependent on regional antibiotic susceptibility patterns. During summer 2013, an unusual increase in number of diarrheal diseases was noticed in Isfahan, a central province of Iran. Therefore, the antibiotic resistance of diarrheagenic Escherichia coli and Shigella species isolated were evaluated. Materials and Methods: According to the guideline on National Surveillance System for Foodborn Diseases, random samples from patients with acute diarrhea were examined in local laboratories of health centers and samples suspicious of Shigella spp. were further assessed in referral laboratory. Isolated pathogens were identified by standard biochemical and serologic tests and antibiotic susceptibility testing was carried out by disc diffusion method. Results: A total of 1086 specimens were obtained and 58 samples suspicious of Shigella were specifically evaluated. The most prevalent isolated pathogen was Shigella sonnei (26/58) followed by E. coli (25/58) and Shigella flexneri (3/58). A large number of isolated bacteria were resistant to co-trimoxazole (Shigella spp: 100%, E. coli: 80%), azithromycin (Shigella spp: 70.4%, E. coli: 44.0%), ceftriaxone (Shigella spp: 88.9%, E. coli: 56.0%) and cefixime (Shigella spp: 85.2%, E. coli: 68.0%). About88.3% of S. sonnei isolates, one S. flexneri isolate, and 56% of E. coli strains were resistant to at least three antibiotic classes (multidrug resistant). Conclusion: Due to high levels of resistance to recommended and commonly used antibiotics for diarrhea, continuous monitoring of antibiotic resistance seems essential for determining best options of empirical therapy. PMID:25002896

Sadeghabadi, Azam Fatahi; Ajami, Ali; Fadaei, Reza; Zandieh, Masoud; Heidari, Elham; Sadeghi, Mahmoud; Ataei, Behrooz; Hoseini, Shervin Ghaffari

2014-01-01

425

Effect of bile on growth, peritoneal absorption, and blood clearance of Escherichia coli in E coli peritonitis  

SciTech Connect

The effect of intraperitoneal bile on growth, peritoneal absorption, and clearance of Escherichia coli was determined in E coli peritonitis in the rat. In E coli peritonitis, intraperitoneal bacterial counts gradually decreased, whereas they increased (after 2 hours) with subsequent development of bacteremia in E coli plus bile peritonitis. After an intraperitoneal injection of labeled bacteria, blood radioactivity was only initially lower in E coli plus bile peritonitis compared with E coli peritonitis. Clearance from blood was lower in E coli plus bile peritonitis than in E coli peritonitis. Organ localization was similar in E coli peritonitis and E coli plus bile peritonitis with decreased splenic, increased pulmonary, and unchanged hepatic uptakes compared with controls. Impaired peritoneal absorption of bacteria, together with impaired local host defense, is likely to enhance the noxious effect of bile in E coli peritonitis.

Andersson, R.; Schalen, C.; Tranberg, K.G. (Department of Surgery, Lund University, Lund (Sweden))

1991-06-01

426

SbcCD Regulation and Localization in Escherichia coli?  

PubMed Central

The SbcCD complex and its homologues play important roles in DNA repair and in the maintenance of genome stability. In Escherichia coli, the in vitro functions of SbcCD have been well characterized, but its exact cellular role remains elusive. This work investigates the regulation of the sbcDC operon and the cellular localization of the SbcC and SbcD proteins. Transcription of the sbcDC operon is shown to be dependent on starvation and RpoS protein. Overexpressed SbcC protein forms foci that colocalize with the replication factory, while overexpressed SbcD protein is distributed through the cytoplasm. PMID:17644583

Darmon, Elise; Lopez-Vernaza, Manuel A.; Helness, Anne C.; Borking, Amanda; Wilson, Emily; Thacker, Zubin; Wardrope, Laura; Leach, David R. F.

2007-01-01

427

Cell growth and length distribution in Escherichia coli.  

PubMed Central

The length growth rate of an exponentially growing population of Escherichia coli B/r was calculated from the population length and birth length distributions. Cell elongation took place at a constant rate that doubled at a certain length. This change in rate was responsible for a sudden drop in the frequency of classes of cells longer than that length. Asymmetry in cell partition was able to generate cells both shorter and longer than the expected twofold range, but did not greatly modify the length distribution in between. Images PMID:348686

Cullum, J; Vicente, M

1978-01-01

428

Transcription factor distribution in Escherichia coli: studies with FNR protein  

PubMed Central

Using chromatin immunoprecipitation (ChIP) and high-density microarrays, we have measured the distribution of the global transcription regulator protein, FNR, across the entire Escherichia coli chromosome in exponentially growing cells. Sixty-three binding targets, each located at the 5? end of a gene, were identified. Some targets are adjacent to poorly transcribed genes where FNR has little impact on transcription. In stationary phase, the distribution of FNR was largely unchanged. Control experiments showed that, like FNR, the distribution of the nucleoid-associated protein, IHF, is little altered when cells enter stationary phase, whilst RNA polymerase undergoes a complete redistribution. PMID:17164287

Grainger, David C.; Aiba, Hirofumi; Hurd, Douglas; Browning, Douglas F.; Busby, Stephen J. W.

2007-01-01

429

Protein aggregation in Escherichia coli: role of proteases.  

PubMed

Protein aggregation is involved in several human diseases, and presumed to be an important process in protein quality control. In bacteria, aggregation of proteins occurs during stress conditions, such as heat shock. We studied the protein aggregates of Escherichia coli during heat shock. Our results demonstrate that the concentration and diversity of proteins in the aggregates depend on the availability of proteases. Aggregates obtained from mutants in the Lon (La) protease contain three times more protein than wild-type aggregates and show the broadest protein diversity. The results support the assumption that protein aggregates are formed from partially unfolded proteins that were not refolded by chaperones or degraded by proteases. PMID:11886743

Rosen, Ran; Biran, Dvora; Gur, Eyal; Becher, Dörte; Hecker, Michael; Ron, Eliora Z

2002-01-22

430

Molecular Evolution of the Escherichia Coli Chromosome. III. Clonal Frames  

PubMed Central

PCR fragments, 1500-bp, from 15 previously sequenced regions in the Escherichia coli chromosome have been compared by restriction analysis in a large set of wild (ECOR) strains. Prior published observations of segmental clonality are confirmed: each of several sequence types is shared by a number of strains. The rate of recombinational replacement and the average size of the replacements are estimated in a set of closely related strains in which a clonal frame is dotted with occasional stretches of DNA belonging to other clones. A clonal hierarchy is described. Some new comparative sequencing data are presented. PMID:1979037

Milkman, R.; Bridges, M. M.

1990-01-01

431

Molecular serogrouping of porcine enterotoxigenic Escherichia coli from Australia.  

PubMed

Enterotoxigenic Escherichia coli (ETEC) is a common etiological agent of neonatal, pre and post weaning diarrhoea in piglets. One of the most important steps in the diagnosis and epidemiological understanding of this organism is accurate serogrouping. In many instances, however, conventional serogrouping fails to produce accurate identification of serogroups. In this communication we report a modified and simplified molecular serogrouping method (rfb-RFLP) for the accurate identification of the most common porcine ETEC strains that cause neonatal, pre and post weaning diarrhoea in Australia. PMID:22093999

Abraham, Sam; Chin, James; Brouwers, Huub J M; Zhang, Ren; Chapman, Toni A

2012-01-01

432

Escherichia coli JA221 can suppress the UAG stop signal.  

PubMed

The Escherichia coli strain JA221 can suppress the UAG stop codon, although the existence of an amber suppressor tRNA has not previously been described for this strain. When using a plasmid to express alpha-sarcin, which has TAG as its stop signal, two proteins were obtained: a smaller protein corresponding in size to that of the expected protein, and a larger protein, which could be accounted for by the presence of a second stop codon (TGA) 18 base pairs downstream of the original. This feature of strain JA221 must therefore be considered when using this strain as a host for the production of recombinant proteins. PMID:7639999

Lacadena, J; Martínez del Pozo, A; Mancheño, J M; Gasset, M; Oñaderra, M; Gavilanes, J G

1995-08-01

433

Nucleotide sequence of the Escherichia coli entE gene.  

PubMed

The Escherichia coli entE gene encodes a polypeptide necessary in the latter stages of biosynthesis of the siderophore enterobactin. The entE gene and adjacent DNA were sequenced. The predicted EntE polypeptide consists of 536 amino acids and has a Mr of 58,299 and a net charge of -7.33. Genetic evidence combined with this and previous sequencing data indicate that the genes entCEB(G)A are transcribed as unit from a promoter upstream of entC. PMID:2525505

Staab, J F; Elkins, M F; Earhart, C F

1989-05-01

434

Microcin 25, a novel antimicrobial peptide produced by Escherichia coli.  

PubMed Central

Microcin 25, a peptide antibiotic excreted by an Escherichia coli strain isolated from human feces, was purified to homogeneity and characterized. Composition analysis and data from gel filtration indicated that microcin 25 may contain 20 amino acid residues. It has a blocked amino-terminal end. Microcin synthesis and immunity are plasmid determined, and the antibiotic was produced in minimal medium when the cultures entered the stationary phase of growth. The peptide appears to interfere with cell division, since susceptible cells filamented when exposed to it. This response does not seem to be mediated by the SOS system. Images PMID:1429464

Salomón, R A; Farías, R N

1992-01-01

435

Escherichia coli response to exogenous pyrophosphate and analogs.  

PubMed

The addition of exogenous pyrophosphate increases the growth yield and cAMP synthesis in stationary phase when Escherichia coli is grown in minimal medium. Pyrophosphate increases the yield by altering the enterobactin uptake system. We studied the physiological effects and examined how the E. coli transcriptome was modified when two structural analogs of pyrophosphate were added to the growth medium. Methylenediphosphonic acid or a high concentration of iron had the same positive effects as pyrophosphate on growth yield, cAMP synthesis and the repression of Fur-regulated genes. In contrast, imidodiphosphate did not affect these cellular processes significantly. The transcriptome modifications generated by pyrophosphate or methylenediphosphonic acid were more similar than those generated by imidodiphosphate or excess iron. The transcriptome data also indicated that processes other than iron uptake might be involved in the cellular response to exogenous pyrophosphate or methylenediphosphonic acid. PMID:12673060

Biville, Francis; Oshima, Taku; Mori, Hirotada; Kawagoe, Yuya; Bouvet, Odile; Rager, Marie-Noëlle; Perrotte-Piquemal, Marina; Danchin, Antoine

2003-01-01

436

Mounting of Escherichia coli spheroplasts for AFM imaging.  

SciTech Connect

The cytoplasmic membrane of Escherichia coli (E. coli) is the location of numerous, chemically specific transporters and recognition elements. Investigation of this membrane in vivo by atomic force microscopy (AFM) requires removal of the cell wall and stable immobilization of the spheroplast. AFM images demonstrate that spheroplasts can be secured with warm gelatin applied to the mica substrate just before the addition of a spheroplast suspension. The resulting preparation can be repeatedly imaged by AFM over the course of several hours. Confocal fluorescence imaging confirms the association of the spheroplasts with the gelatin layer. Gelatin molecules are known to reorder into a network after heating. Entrapment within this gelatin network is believed to be responsible for the immobilization of spheroplasts on mica.

Sullivan, Claretta J [ORNL; Morrell-Falvey, Jennifer L [ORNL; Allison, David P [ORNL; Doktycz, Mitchel John [ORNL

2005-11-01

437

Isolation and characterization of isoprene mutants of Escherichia coli.  

PubMed Central

Isoprenoid compounds are found in all organisms. In Escherichia coli the isoprene pathway has three distinct branches: the modification of tRNA; the respiratory quinones ubiquinone and menaquinone; and the dolichols, which are long-chain alcohols involved in cell wall biosynthesis. Very little is known about procaryotic isoprene biosynthesis compared with what is known about eucaryote isoprene biosynthesis. This study approached some of the questions about isoprenoid biosynthesis and regulation in procaryotes by isolating and characterizing mutants in E. coli. Mutants were selected by determining their resistance to low levels of aminoglycoside antibiotics, which require an electron transport chain for uptake into bacterial cells. The mutants were characterized with regard to their phenotypes, map positions, enzymatic activities, and total ubiquinone content. In particular, the enzymes studied were isopentenyldiphosphate delta-isomerase (EC 5.3.3.2), farnesyldiphosphate synthetase (EC 2.5.1.1), and higher prenyl transferases. PMID:2661529

Sherman, M M; Petersen, L A; Poulter, C D

1989-01-01

438

Global Analysis of Extracytoplasmic Stress Signaling in Escherichia coli  

PubMed Central

The Bae, Cpx, Psp, Rcs, and ?E pathways constitute the Escherichia coli signaling systems that detect and respond to alterations of the bacterial envelope. Contributions of these systems to stress response have previously been examined individually; however, the possible interconnections between these pathways are unknown. Here we investigate the dynamics between the five stress response pathways by determining the specificities of each system with respect to signal-inducing conditions, and monitoring global transcriptional changes in response to transient overexpression of each of the effectors. Our studies show that different extracytoplasmic stress conditions elicit a combined response of these pathways. Involvement of the five pathways in the various tested stress conditions is explained by our unexpected finding that transcriptional responses induced by the individual systems show little overlap. The extracytoplasmic stress signaling pathways in E. coli thus regulate mainly complementary functions whose discrete contributions are integrated to mount the full adaptive response. PMID:19763168

Bury-Mone, Stephanie; Nomane, Yanoura; Reymond, Nancie; Barbet, Romain; Jacquet, Eric; Imbeaud, Sandrine; Jacq, Annick; Bouloc, Philippe

2009-01-01

439

Genetic characterization of moaB mutants of Escherichia coli.  

PubMed

The moaABCDE operon of Escherichia coli encodes enzymes essential for the biosynthesis of the molybdenum cofactor (Moco). However, the role of the moaB gene within this operon has remained enigmatic. Here, we have investigated the effect of moaB defects on two phenotypes diagnostic for Moco-deficiency: chlorate-resistance and sensitivity to the base analog 6-N-hydroxylaminopurine (HAP). We found that transposon insertions in moaB caused partial Moco-deficiency associated with chlorate-resistance, but not for HAP-sensitivity. On the other hand, in-frame deletions of moaB, or moaB overexpression, had no effect on either phenotype. Our combined data are consistent with the lack of any role for MoaB in Moco biosynthesis in E. coli. PMID:23680484

Kozmin, Stanislav G; Schaaper, Roel M

2013-09-01

440

Cellulosic hydrolysate toxicity and tolerance mechanisms in Escherichia coli  

PubMed Central

The sustainable production of biofuels will require the efficient utilization of lignocellulosic biomass. A key barrier involves the creation of growth-inhibitory compounds by chemical pretreatment steps, which ultimately reduce the efficiency of fermentative microbial biocatalysts. The primary toxins include organic acids, furan derivatives, and phenolic compounds. Weak acids enter the cell and dissociate, resulting in a drop in intracellular pH as well as various anion-specific effects on metabolism. Furan derivatives, dehydration products of hexose and pentose sugars, have been shown to hinder fermentative enzyme function. Phenolic compounds, formed from lignin, can disrupt membranes and are hypothesized to interfere with the function of intracellular hydrophobic targets. This review covers mechanisms of toxicity and tolerance for these compounds with a specific focus on the important industrial organism Escherichia coli. Recent efforts to engineer E. coli for improved tolerance to these toxins are also discussed. PMID:19832972

Mills, Tirzah Y; Sandoval, Nicholas R; Gill, Ryan T

2009-01-01

441

Atypical Enteropathogenic Escherichia coli Infection and Prolonged Diarrhea in Children  

PubMed Central

Some clinical isolates of enteropathogenic Escherichia coli (EPEC) lack bundle-forming pili and are termed atypical EPEC. The aim of this study was to determine if atypical EPEC are pathogens by comparing the clinical features of patients infected with atypical EPEC with those of children infected with other causative agents of diarrhea. Fecal samples obtained from children attending the Royal Children's Hospital in Melbourne for investigation of diarrhea were examined for adenovirus, rotavirus, Campylobacter spp., Salmonella spp., protozoa, and pathogenic E. coli. Clinical data were obtained by using a standardized pro forma and analyzed separately. Patients infected with atypical EPEC experienced mild, nondehydrating, and noninflammatory diarrhea that was not particularly associated with fever, vomiting, or abdominal pain. However, the duration of diarrhea in patients infected with atypical EPEC was significantly longer than that caused by the other species or where no pathogens were identified. Infection with atypical EPEC is associated with prolonged diarrhea. PMID:16704807

Nguyen, Rang N.; Taylor, Louise S.; Tauschek, Marija

2006-01-01

442

Purification and Characterization of Escherichia coli MreB Protein*  

PubMed Central

The actin homolog MreB is required in rod-shaped bacteria for maintenance of cell shape and is intimately connected to the holoenzyme that synthesizes the peptidoglycan layer. The protein has been reported variously to exist in helical loops under the cell surface, to rotate, and to move in patches in both directions around the cell surface. Studies of the Escherichia coli protein in vitro have been hampered by its tendency to aggregate. Here we report the purification and characterization of native E. coli MreB. The protein requires ATP hydrolysis for polymerization, forms bundles with a left-hand twist that can be as long as 4 ?m, forms sheets in the presence of calcium, and has a critical concentration for polymerization of 1.5 ?m. PMID:23235161

Nurse, Pearl; Marians, Kenneth J.

2013-01-01

443

Production of Disulfide-Bonded Proteins in Escherichia coli.  

PubMed

Production of recombinant proteins at high yields in Escherichia coli requires extensive optimization of expression conditions. Production is further complicated for proteins that require specific post-translational modifications for their eventual folding. One common and particularly important post-translational modification is oxidation of the correct pair of cysteines to form a disulfide bond. This unit describes methods to produce disulfide-bonded proteins in E. coli in either the naturally oxidizing periplasm or the cytoplasm of appropriately engineered cells. The focus is on variables key to improving the oxidative folding of disulfide-bonded proteins, with the aim of helping the researcher optimize expression conditions for a protein of interest. Curr. Protoc. Mol. Biol. 108:16.1B.1-16.1B.21. © 2014 by John Wiley & Sons, Inc. PMID:25271713

Ke, Na; Berkmen, Mehmet

2014-01-01

444

Nanomechanical motion of Escherichia coli adhered to a surface  

NASA Astrophysics Data System (ADS)

Nanomechanical motion of bacteria adhered to a chemically functionalized silicon surface is studied by means of a microcantilever. A non-specific binding agent is used to attach Escherichia coli (E. coli) to the surface of a silicon microcantilever. The microcantilever is kept in a liquid medium, and its nanomechanical fluctuations are monitored using an optical displacement transducer. The motion of the bacteria couples efficiently to the microcantilever well below its resonance frequency, causing a measurable increase in the microcantilever fluctuations. In the time domain, the fluctuations exhibit large-amplitude low-frequency oscillations. In corresponding frequency-domain measurements, it is observed that the mechanical energy is focused at low frequencies with a 1/f?-type power law. A basic physical model is used for explaining the observed spectral distribution of the mechanical energy. These results lay