scholarly journals In Vivo Phase Variation of Escherichia coli Type 1 Fimbrial Genes in Women with Urinary Tract Infection

1998 ◽  
Vol 66 (7) ◽  
pp. 3303-3310 ◽  
Author(s):  
Jean K. Lim ◽  
Nereus W. Gunther ◽  
Hui Zhao ◽  
David E. Johnson ◽  
Susan K. Keay ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Acute Pyelonephritis ◽  
Urine Samples ◽  
E Coli ◽  
Type 1 Fimbriae ◽  
Tract Infections

ABSTRACT Type 1 fimbriae, expressed by most Escherichia colistrains, are thought to attach to human uroepithelium as an initial step in the pathogenesis of urinary tract infections (UTI). Numerous reports using both in vitro and murine models support this role for type 1 fimbriae in colonization. Unfortunately, only a limited number of studies have directly examined the expression of fimbriae in vivo. To determine whether type 1 fimbrial genes are transcribed during an acute UTI, we employed a modification of an established method. The orientation (ON or OFF) of the invertible promoter element, which drives transcription of type 1 fimbrial genes, was determined by PCR amplification using primers that flank the invertible element, followed by SnaBI digestion. The orientation of the type 1 fimbrial switch was determined under three experimental conditions. First,E. coli strains from different clinical sources (acute pyelonephritis patients, cystitis patients, and fecal controls) were tested under different in vitro culture conditions (agar versus broth; aerated versus static). The genes in the more-virulent strains (those causing acute pyelonephritis) demonstrated a resistance, in aerated broth, to switching from OFF to ON, while those in fecal strains readily switched from OFF to ON. Second, bladder and kidney tissue from CBA mice transurethrally inoculated with E. coli CFT073 (an established murine model of ascending UTI) was assayed. The switches directly amplified from infected bladder and kidney tissues were estimated to be 33 and 39% ON, respectively, by using a standard curve. Finally, bacteria present in urine samples collected from women with cystitis were tested for type 1 fimbria switch orientation. For all 11 cases, an average of only 4% of the switches in the bacteria in the urine were ON. In 7 of the 11 cases, we found that all of the visible type 1 fimbrial switches were in the OFF position (upper limit of detection of assay, 98% OFF). Strains recovered from these urine samples, however, were shown after culture in vitro to be capable of switching the fimbrial gene to the ON position and expressing mannose-sensitive hemagglutinin. The results from experimental infections and cases of cystitis in women suggest that type 1 fimbrial genes are transcribed both in the bladder and in the kidney. However, those bacteria found in the urine and not attached to the uroepithelium are not transcriptionally active for type 1 fimbrial genes.

scholarly journals Biological Cost of Single and Multiple Norfloxacin Resistance Mutations in Escherichia coli Implicated in Urinary Tract Infections

2005 ◽  
Vol 49 (6) ◽  
pp. 2343-2351 ◽  
Author(s):  
Patricia Komp Lindgren ◽  
Linda L. Marcusson ◽  
Dorthe Sandvang ◽  
Niels Frimodt-Møller ◽  
Diarmaid Hughes
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Infection Model ◽  
Resistance Mutations ◽  
Topoisomerase Iv ◽  
E Coli ◽  
Tract Infections ◽  
Subsequent Selection

ABSTRACT Resistance to fluoroquinolones in urinary tract infection (UTIs) caused by Escherichia coli is associated with multiple mutations, typically those that alter DNA gyrase and DNA topoisomerase IV and those that regulate AcrAB-TolC-mediated efflux. We asked whether a fitness cost is associated with the accumulation of these multiple mutations. Mutants of the susceptible E. coli UTI isolate Nu14 were selected through three to five successive steps with norfloxacin. Each selection was performed with the MIC of the selected strain. After each selection the MIC was measured; and the regions of gyrA, gyrB, parC, and parE, previously associated with resistance mutations, and all of marOR and acrR were sequenced. The first selection step yielded mutations in gyrA, gyrB, and marOR. Subsequent selection steps yielded mutations in gyrA, parE, and marOR but not in gyrB, parC, or acrR. Resistance-associated mutations were identified in almost all isolates after selection steps 1 and 2 but in less than 50% of isolates after subsequent selection steps. Selected strains were competed in vitro, in urine, and in a mouse UTI infection model against the starting strain, Nu14. First-step mutations were not associated with significant fitness costs. However, the accumulation of three or more resistance-associated mutations was usually associated with a large reduction in biological fitness, both in vitro and in vivo. Interestingly, in some lineages a partial restoration of fitness was associated with the accumulation of additional mutations in late selection steps. We suggest that the relative biological costs of multiple mutations may influence the evolution of E. coli strains that develop resistance to fluoroquinolones.

scholarly journals Determination of nitrofurantoin and fosfomycin susceptibility among urinary Escherichia coli isolates

2020 ◽  
Vol 8 (9) ◽  
pp. 3274
Author(s):  
Rachana Kanaujia ◽  
Amit Kumar ◽  
Malay Bajpai
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Urine Samples ◽  
E Coli ◽  
Tract Infections ◽  
Therapeutic Alternatives ◽  
Micro Organisms ◽  
Staphylococcus Spp

Background: Urinary tract infections (UTIs) are one of the most common infections. For treatment of UTIs, there are limited antibiotics due to increased resistance among uropathogens. Two older antibiotics; Nitrofurantoin and Fosfomycin have become novel oral therapeutic options against uropathogens. Aim of the study was to identify UTI causing micro-organisms and evaluate in-vitro activity of nitrofurantoin and fosfomycin against most common isolated organism (E. coli).Methods: Results of urine samples culture and susceptibility testing over a period of 1 year were analysed and included in this study.Results: Micro-organisms were isolated from 568 urine samples. Most commonly isolated organism was Escherichia coli (40.50%), followed by Klebsiella spp. (20.07%) and Staphylococcus spp. (17.07%). Susceptibility of E. coli to nitrofurantoin and fosfomycin was 91.74% and 65.65% respectively. Conclusion: Good activity of nitrofurantoin and fosfomycin against E. coli indicates that these two drugs are potential therapeutic alternatives for urinary tract infections.

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

2004 ◽  
Vol 72 (8) ◽  
pp. 4570-4578 ◽  
Author(s):  
Robert Blomgran ◽  
Limin Zheng ◽  
Olle Stendahl
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Human Neutrophils ◽  
Dependent Manner ◽  
E Coli ◽  
Type 1 Fimbriae ◽  
The Difference ◽  
Tract Infections ◽  
Neutrophil Survival

ABSTRACT Type 1 fimbriae are the most commonly expressed virulence factor on uropathogenic Escherichia coli. In addition to promoting avid bacterial adherence to the uroepithelium and enabling colonization, type 1 fimbriae recruit neutrophils to the urinary tract as an early inflammatory response. Using clinical isolates of type 1 fimbriated E. coli and an isogenic type 1 fimbria-negative mutant (CN1016) lacking the FimH adhesin, we investigated if these strains could modulate apoptosis in human neutrophils. We found that E. coli expressing type 1 fimbriae interacted with neutrophils in a mannose- and lipopolysaccharide (LPS)-dependent manner, leading to apoptosis which was triggered by the intracellular generation of reactive oxygen species. This induced neutrophil apoptosis was abolished by blocking FimH-mediated attachment, by inhibiting NADPH oxidase activation, or by neutralizing LPS. In contrast, CN1016, which did not adhere to or activate the respiratory burst of neutrophils, delayed the spontaneous apoptosis in an LPS-dependent manner. This delayed apoptosis could be mimicked by adding purified LPS and was also observed by using fimbriated bacteria in the presence of d-mannose. These results suggest that LPS is required for E. coli to exert both pro- and antiapoptotic effects on neutrophils and that the difference in LPS presentation (i.e., with or without fimbriae) determines the outcome. The present study showed that there is a fine-tuned balance between type 1 fimbria-induced and LPS-mediated delay of apoptosis in human neutrophils, in which altered fimbrial expression on uropathogenic E. coli determines the neutrophil survival and the subsequent inflammation during urinary tract infections.

scholarly journals Escherichia coli CFT073 Fitness Factors during Urinary Tract Infection: Identification Using an Ordered Transposon Library

2020 ◽  
Vol 86 (13) ◽  
Author(s):  
Allyson E. Shea ◽  
Juan Marzoa ◽  
Stephanie D. Himpsl ◽  
Sara N. Smith ◽  
Lili Zhao ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Human Urine ◽  
Transposon Mutagenesis ◽  
Content Type ◽  
E Coli ◽  
Tract Infections

ABSTRACT Urinary tract infections (UTI), the second most diagnosed infectious disease worldwide, are caused primarily by uropathogenic Escherichia coli (UPEC), placing a significant financial burden on the health care system. High-throughput transposon mutagenesis combined with genome-targeted sequencing is a powerful technique to interrogate genomes for fitness genes. Genome-wide analysis of E. coli requires random libraries of at least 50,000 mutants to achieve 99.99% saturation; however, the traditional murine model of ascending UTI does not permit testing of large mutant pools due to a bottleneck during infection. To address this, an E. coli CFT073 transposon mutant ordered library of 9,216 mutants was created and insertion sites were identified. A single transposon mutant was selected for each gene to assemble a condensed library consisting of 2,913 unique nonessential mutants. Using a modified UTI model in BALB/c mice, we identified 36 genes important for colonizing the bladder, including purB, yihE, and carB. Screening of the condensed library in vitro identified yigP and ubiG to be essential for growth in human urine. Additionally, we developed a novel quantitative PCR (qPCR) technique to identify genes with fitness defects within defined subgroups of related genes (e.g., genes encoding fimbriae, toxins, etc.) following UTI. The number of mutants within these subgroups circumvents bottleneck restriction and facilitates validation of multiple mutants to generate individual competitive indices. Collectively, this study investigates the bottleneck effects during UTI, provides two techniques for evading those effects that can be applied to other disease models, and contributes a genetic tool in prototype strain CFT073 to the field. IMPORTANCE Uropathogenic Escherichia coli strains cause most uncomplicated urinary tract infections (UTI), one of the most common infectious diseases worldwide. Random transposon mutagenesis techniques have been utilized to identify essential bacterial genes during infection; however, this has been met with limitations when applied to the murine UTI model. Conventional high-throughput transposon mutagenesis screens are not feasible because of inoculum size restrictions due to a bottleneck during infection. Our study utilizes a condensed ordered transposon library, limiting the number of mutants while maintaining the largest possible genome coverage. Screening of this library in vivo, and in human urine in vitro, identified numerous candidate fitness factors. Additionally, we have developed a novel technique using qPCR to quantify bacterial outputs following infection with small subgroups of transposon mutants. Molecular approaches developed in this study will serve as useful tools to probe in vivo models that are restricted by anatomical, physiological, or genetic bottleneck limitations.

scholarly journals Bacterial Profile of Urinary Tract Infections: Evaluation of Biofilm Formation and Antibiotic Resistance Pattern of Uropathogenic Escherichia coli

2020 ◽  
Vol 14 (4) ◽  
pp. 2577-2584
Author(s):  
Tariq Ahmad Shah ◽  
P. Preethishree ◽  
Ashwini ◽  
Vidya Pai
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Urinary Tract ◽  
Biofilm Formation ◽  
Urine Samples ◽  
Diffusion Method ◽  
E Coli ◽  
Biofilm Production ◽  
Tract Infections

Urinary tract infection (UTI) is one of the most common complaints in the outpatient clinic and a major health problem owing to the emergence of antibiotic resistance and biofilm formation. The objective of this study was to isolate and identify the causative bacterial agent of UTI and detect in vitro biofilm formation by Escherichia coli and investigate its correlation with antibiotic resistance. Urine samples from 519 patients with suspected UTIs were collected and processed by conventional microbiological procedures. Antimicrobial susceptibility testing for E. coli isolates was performed on Mueller Hinton agar (MHA) plates using the Kirby-Bauer disk diffusion method. Biofilm production was evaluated using the tissue culture plate method. Of 519 urine samples, 115 (22.1%) showed significant bacteriuria. The most common isolate was E. coli (n=57, 49.6%), followed by Klebsiella spp. (n=23, 20%). All E. coli isolates were evaluated for their ability to form biofilms in vitro. Of 57 isolates, 50 (87.7%) were biofilm producers and 7 (12.3%) were non-biofilm producers. Antibiogram of E. coli isolates revealed the highest resistance to ampicillin (96.5%) and nitrofurantoin (91.2%), followed by amoxyclav (82.5%), ceftazidime (73.7%), cefepime (71.9%), and tetracycline (71.9%). A significant association (p<0.05) was observed between biofilm formation and resistance to amoxyclav, ceftazidime, cefepime, imipenem, and nitrofurantoin. A significant correlation was noted between biofilm production and antibiotic resistance. Hence, screening of all isolates of uropathogenic E. coli for biofilm production and studying their antibiogram would allow appropriate choice of antibiotic therapy.

scholarly journals Adhesion of Escherichia Coli to Nanostructured Surfaces and the Role of Type 1 Fimbriae

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2247
Author(s):  
Pawel Kallas ◽  
Håvard J Haugen ◽  
Nikolaj Gadegaard ◽  
John Stormonth-Darling ◽  
Mats Hulander ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Virulence Factor ◽  
Wild Type ◽  
E Coli ◽  
Type 1 Fimbriae ◽  
Tract Infections

Bacterial fimbriae are an important virulence factor mediating adhesion to both biotic and abiotic surfaces and facilitating biofilm formation. The expression of type 1 fimbriae of Escherichia coli is a key virulence factor for urinary tract infections and catheter-associated urinary tract infections, which represent the most common nosocomial infections. New strategies to reduce adhesion of bacteria to surfaces is therefore warranted. The aim of the present study was to investigate how surfaces with different nanotopography-influenced fimbriae-mediated adhesion. Surfaces with three different nanopattern surface coverages made in polycarbonate were fabricated by injection molding from electron beam lithography nanopatterned templates. The surfaces were constructed with features of approximately 40 nm width and 25 nm height with 100 nm, 250 nm, and 500 nm interspace distance, respectively. The role of fimbriae type 1-mediated adhesion was investigated using the E. coli wild type BW25113 and ΔfimA (with a knockout of major pilus protein FimA) and ΔfimH (with a knockout of minor protein FimH) mutants. For the surfaces with nanotopography, all strains adhered least to areas with the largest interpillar distance (500 nm). For the E. coli wild type, no difference in adhesion between surfaces without pillars and the largest interpillar distance was observed. For the deletion mutants, increased adhesion was observed for surfaces without pillars compared to surfaces with the largest interpillar distance. The presence of a fully functional type 1 fimbria decreased the bacterial adhesion to the nanopatterned surfaces in comparison to the mutants.

scholarly journals Coordinate Expression of Fimbriae in Uropathogenic Escherichia coli

2005 ◽  
Vol 73 (11) ◽  
pp. 7588-7596 ◽  
Author(s):  
Jennifer A. Snyder ◽  
Brian J. Haugen ◽  
C. Virginia Lockatell ◽  
Nathalie Maroncle ◽  
Erin C. Hagan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Gene Clusters ◽  
Phase Variable ◽  
Type 1 Fimbriae ◽  
Coordinated Expression ◽  
Tract Infections

ABSTRACT Uropathogenic Escherichia coli is the most common etiological agent of urinary tract infections. Bacteria can often express multiple adhesins during infection in order to favor attachment to specific niches within the urinary tract. We have recently demonstrated that type 1 fimbria, a phase-variable virulence factor involved in adherence, was the most highly expressed adhesin during urinary tract infection. Here, we examine whether the expression of type 1 fimbriae can affect the expression of other adhesins. Type 1 fimbrial phase-locked mutants of E. coli strain CFT073, which harbors genes for numerous adhesins, were employed in this study. CFT073-specific DNA microarray analysis of these strains demonstrates that the expression of type 1 fimbriae coordinately affects the expression of P fimbriae in an inverse manner. This represents evidence for direct communication between genes relating to pathogenesis, perhaps to aid the sequential occupation of different urinary tract tissues. While the role of type 1 fimbriae during infection has been clear, the role of P fimbriae must be further defined to assert the relevance of coordinated regulation in vivo. Therefore, we examined the ability of P fimbrial isogenic mutants, constructed in a type 1 fimbrial-negative background, to compete in the murine urinary tract over a period of 168 h. No differences in the colonization of these mutants were observed. However, comparison of these results with previous studies suggests that inversely coordinated expression of adhesin gene clusters does occur in vivo. Interestingly, the mutant that was incapable of expressing either type 1 or P fimbriae compensated by synthesizing F1C fimbriae.

scholarly journals Dissecting and Evaluating the Therapeutic Targets of Coptis Chinensis Franch in the Treatment of Urinary Tract Infections Induced by Escherichia coli

2022 ◽  
Vol 12 ◽  
Author(s):  
Zhenglin Chang ◽  
Jinhu Zhang ◽  
Min Lei ◽  
Zheng Jiang ◽  
Xiangkun Wu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Host Cells ◽  
Network Pharmacology ◽  
Coptis Chinensis ◽  
E Coli ◽  
Tract Infections

Coptis chinensis Franch (CCF) is extensively used in the treatment of inflammatory-related diseases. Accumulating studies have previously demonstrated the anti-inflammatory properties of CCF, yet data on its exact targets against urinary tract infections (UTIs) remain largely unknown. Therefore, the present study decodes the potential targets of action of CCF against UTIs by network pharmacology combined with experiment evaluations. Based on the pharmacology network analysis, the current study yielded six core ingredients: quercetin, palmatine (R)-canadine, berlambine, berberine, and berberrubine. The protein–protein interaction network (PPI) was generated by the string database, and then, four targets (IL6, FOS, MYC, and EGFR) were perceived as the major CCF targets using the CytoNCA plug-in. The results of molecular docking showed that the six core constituents of CCF had strong binding affinities toward the four key targets of UTIs after docking into the crystal structure. The enrichment analysis indicated that the possible regulatory mechanisms of CCF against UTIs were based on the modules of inflammation, immune responses, and apoptosis among others. Experimentally, the Escherichia coli (E. coli) strain CFT073 was applied to establish in vivo and in vitro models. In vivo results revealed that the key targets, IL6 and FOS, are significantly upregulated in rat bladder tissues of UTIs, whereas the expression of MYC and EGFR remained steady. Last, in vitro results further confirmed the therapeutic potential of CCF by reducing the expression of IL6 and FOS. In conclusion, IL6 and FOS were generally upregulated in the progression of E. coli–induced UTIs, whereas the CCF intervention exerted a preventive role in host cells stimulated by E. coli, partially due to inhibiting the expression of IL6 and FOS.

scholarly journals Production of pili, hemolysin and siderophores in the urinary isolates of Escherichia coli

2013 ◽  
Vol 141 (9-10) ◽  
pp. 634-639
Author(s):  
Tatjana Markovic ◽  
Aleksandra Smitran ◽  
Miroslav Petkovic
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Virulence Factors ◽  
Test Plate ◽  
E Coli ◽  
Type 1 Fimbriae ◽  
Significant Difference ◽  
Tract Infections ◽  
Urinary Isolates

Introduction. Escherichia coli (E. coli) are the most frequent cause of the urinary tract infections. Uropathogenic E. coli (UPEC) produce virulence factors which enable them to survive in the urinary tract and cause an infection. Objective. The objective of this study was to determine phenotype characterization of E. coli isolated from outpatients? urine in the region of Banja Luka over three-year period. In line with the objective, the following research tasks were set up: determining the production of type 1 fimbriae, P-pili, ?-hemolysin and siderophores. Methods. A total of 417 urinary isolates and 100 control intestinal isolates were screened for virulence factors. Production of adhesions was confirmed by haemagglutination test. Plate haemolysis test was done for the detection of ?-hemolysin, and siderophores production assay was carried out by using the method named chrome azurol sulfonate agar diffusion assay. Results. In the group of urinary isolates, almost 60% of isolates produced two or three virulence factors; only 3.8% produced none of the virulence factors. In the group of intestinal isolates, even 43% of isolates produced none of the virulence factors while 48% of isolates produced a single virulence factor and 9% produced two virulence factors. Conclusion. Urinary isolates E. coli express significantly more P-pili, ?-hemolysin and siderophore than intestinal isolates (p<0.001). There was no significant difference in production of type 1 fimbriae among the urinary and intestinal isolates.

scholarly journals Cefoxitin as an Alternative to Carbapenems in a Murine Model of Urinary Tract Infection Due to Escherichia coli Harboring CTX-M-15-Type Extended-Spectrum β-Lactamase

2012 ◽  
Vol 56 (3) ◽  
pp. 1376-1381 ◽  
Author(s):  
Raphaël Lepeule ◽  
Etienne Ruppé ◽  
Patrick Le ◽  
Laurent Massias ◽  
Françoise Chau ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Murine Model ◽  
Content Type ◽  
E Coli ◽  
Extended Spectrum ◽  
Drug Concentrations ◽  
Tract Infections

ABSTRACTWe investigated the efficiency of the cephamycin cefoxitin as an alternative to carbapenems for the treatment of urinary tract infections (UTIs) due toEscherichia coliproducing CTX-M-type extended-spectrum β-lactamases. The susceptible, UTI-inducingE. coliCFT073-RR strain and its transconjugant CFT073-RR Tc (pblaCTX-M-15), harboring ablaCTX-M-15carrying-plasmid, were used for all experiments. MICs of cefoxitin (FOX), ceftriaxone (CRO), imipenem (IMP), and ertapenem (ETP) for CFT073-RR and CFT073-RR Tc (pblaCTX-M-15) were 4 and 4, 0.125 and 512, 0.5 and 0.5, and 0.016 and 0.032 μg/ml, respectively. Bactericidal activity was similarly achievedin vitroagainst the two strains after 3 h of exposure to concentrations of FOX, IMI, and ETP that were 2 times the MIC, whereas CRO was not bactericidal against CFT073-RR Tc (pblaCTX-M-15). The frequencies of spontaneous mutants of the 2 strains were not higher for FOX than for IMP or ETP. In the murine model of UTIs, mice infected for 5 days were treated over 24 h. Therapeutic regimens in mice (200 mg/kg of body weight every 3 h or 4 h for FOX, 70 mg/kg every 6 h for CRO, 100 mg/kg every 2 h for IMP, and 100 mg/kg every 4 h for ETP) were chosen in order to reproduce the percentage of time that free-drug concentrations above the MIC are obtained in humans with standard regimens. All antibiotic regimens produced a significant reduction in bacterial counts (greater than 2 log10CFU) in kidneys and bladders for both strains (P< 0.001) without selecting resistant mutantsin vivo, but the reduction obtained with CRO against CFT073-RR Tc (pblaCTX-M-15) in kidneys was significantly lower than that obtained with FOX. In conclusion, FOX appears to be an effective therapeutic alternative to carbapenems for the treatment of UTIs due to CTX-M-producingE. coli.

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