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

2002 ◽  
Vol 70 (7) ◽  
pp. 3344-3354 ◽  
Author(s):  
Nereus W. Gunther IV ◽  
Jennifer A. Snyder ◽  
Virginia Lockatell ◽  
Ian Blomfield ◽  
David E. Johnson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Invertible Element ◽  
Transcriptional Level ◽  
Wild Type ◽  
Invertible Elements ◽  
Tract Infections

ABSTRACT 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.

scholarly journals In Vivo Dynamics of Type 1 Fimbria Regulation in UropathogenicEscherichia coli during Experimental Urinary Tract Infection

2001 ◽  
Vol 69 (5) ◽  
pp. 2838-2846 ◽  
Author(s):  
Nereus W. Gunther ◽  
Virginia Lockatell ◽  
David E. Johnson ◽  
Harry L. T. Mobley
Keyword(s):  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Invertible Element ◽  
Molecular Techniques ◽  
E Coli ◽  
Type 1 Fimbriae ◽  
Invertible Elements

ABSTRACT Escherichia coli is the primary cause of uncomplicated infections of the urinary tract including cystitis. More serious infections, characterized as acute pyelonephritis, can also develop. Type 1 fimbriae of E. coli contribute to virulence in the urinary tract; however, only recently has the expression of the type 1 fimbriae been investigated in vivo using molecular techniques. Transcription of type 1 fimbrial genes is controlled by a promoter that resides on a 314-bp invertible element capable of two orientations. One places the promoter in the ON orientation, allowing for transcription; the other places the promoter in the OFF orientation, preventing transcription. A PCR-based assay was developed to measure the orientation of the invertible element during an experimental urinary tract infection in mice. Using this assay, it was found that the percentage of the population ON in urine samples correlated with the respective CFU per gram of bladder (P = 0.0006) but not with CFU per gram of kidney (P > 0.069). Cystitis isolates present in the urine of mice during the course of infection had a higher percentage of their invertible elements in the ON orientation than did pyelonephritis isolates (85 and 34%, respectively, at 24 h; P < 0.0001). In general, cystitis isolates, unlike pyelonephritis isolates, were more likely to maintain their invertible elements in the ON orientation for the entire period of infection. E. coli cells expressing type 1 fimbriae, expelled in urine, were shown by scanning electron microscopy to be densely packed on the surface of uroepithelial cells. These results suggest that expression of type 1 fimbriae is more critical for cystitis strains than for pyelonephritis strains in the early stages of an infection during bladder colonization.

scholarly journals Role of Phase Variation of Type 1 Fimbriae in a Uropathogenic Escherichia coli Cystitis Isolate during Urinary Tract Infection

2006 ◽  
Vol 74 (2) ◽  
pp. 1387-1393 ◽  
Author(s):  
Jennifer A. Snyder ◽  
Amanda L. Lloyd ◽  
C. Virginia Lockatell ◽  
David E. Johnson ◽  
Harry L. T. Mobley
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Invertible Element ◽  
Phase Variation ◽  
Type 1 Fimbriae ◽  
Constitutive Production

ABSTRACT Type 1 fimbrial phase-locked mutants of uropathogenic Escherichia coli cystitis isolate F11 were used to assess the role of the invertible element during urinary tract infection. Compared to the wild type, the phase-locked off mutant was attenuated, and constitutive production of type 1 fimbriae by the phase-locked on mutant did not provide a competitive advantage.

scholarly journals degS Is Necessary for Virulence and Is among Extraintestinal Escherichia coli Genes Induced in Murine Peritonitis

2003 ◽  
Vol 71 (6) ◽  
pp. 3088-3096 ◽  
Author(s):  
Peter Redford ◽  
Paula L. Roesch ◽  
Rodney A. Welch
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Luria Bertani ◽  
Broth Culture ◽  
Wild Type ◽  
E Coli ◽  
Virulence Attenuation

ABSTRACT Extraintestinal Escherichia coli strains cause meningitis, sepsis, urinary tract infection, and other infections outside the bowel. We examined here extraintestinal E. coli strain CFT073 by differential fluorescence induction. Pools of CFT073 clones carrying a CFT073 genomic fragment library in a promoterless gfp vector were inoculated intraperitoneally into mice; bacteria were recovered by lavage 6 h later and then subjected to fluorescence-activated cell sorting. Eleven promoters were found to be active in the mouse but not in Luria-Bertani (LB) broth culture. Three are linked to genes for enterobactin, aerobactin, and yersiniabactin. Three others are linked to the metabolic genes metA, gltB, and sucA, and another was linked to iha, a possible adhesin. Three lie before open reading frames of unknown function. One promoter is associated with degS, an inner membrane protease. Mutants of the in vivo-induced loci were tested in competition with the wild type in mouse peritonitis. Of the mutants tested, only CFT073 degS was found to be attenuated in peritoneal and in urinary tract infection, with virulence restored by complementation. CFT073 degS shows growth similar to that of the wild type at 37°C but is impaired at 43°C or in 3% ethanol LB broth at 37°C. Compared to the wild type, the mutant shows similar serum survival, motility, hemolysis, erythrocyte agglutination, and tolerance to oxidative stress. It also has the same lipopolysaccharide appearance on a silver-stained gel. The basis for the virulence attenuation is unclear, but because DegS is needed for σE activity, our findings implicate σE and its regulon in E. coli extraintestinal pathogenesis.

scholarly journals Infeções do Trato Urinário numa Coorte de Transplantados Renais

2014 ◽  
Vol 27 (3) ◽  
pp. 364 ◽  
Author(s):  
Ana Bispo ◽  
Milene Fernandes ◽  
Cristina Toscano ◽  
Teresa Marques ◽  
Domingos Machado ◽  
...  
Keyword(s):  
Risk Factors ◽  
Escherichia Coli ◽  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Urinary Tract Infections ◽  
Hospital Admissions ◽  
Female Gender ◽  
Tract Infections

<strong>Introduction:</strong> Urinary tract infection is the most common infectious complication following renal transplantation and its frequency is insufficiently studied in Portugal. The aim of this study was to characterize the incidence of urinary tract infections and recurrent urinary tract infections in renal transplant recipients.<br /><strong>Material and Methods:</strong> This was a retrospective cohort observational study, obtained from clinical files of all patients who received a renal transplant at the Hospital of Santa Cruz, from January 2004 to December 2005, with a mean follow-up period of five years or until date of graft loss, death or loss of follow-up. After a descriptive analysis of the population, we used bivariate tests to identify risk factors for urinary tract infections.<br /><strong>Results:</strong> A total of 127 patients were included, with a 593 patients.year follow-up. We detected 53 patients (41.7%) presenting with at least one episode of urinary tract infection; 21 patients (16.5%) had recurrent urinary tract infection. Female gender was the only risk factor associated with the occurrence of urinary tract infections (p &lt; 0.001, OR = 7.08, RR = 2.95) and recurrent urinary tract infections (p &lt; 0.001, OR = 4.66, RR = 2.83). Escherichia coli (51.6%), Klebsiella pneumoniae (15.5%) and Enterobacter spp (9.9%) were the<br />most frequently identified pathogens. Patients did not reveal an increased mortality or allograft loss. However, urinary tract infections were the most important cause of hospital admissions.<br /><strong>Discussion:</strong> Female gender was the only risk factor for urinary tract infections in this population. Escherichia coli was the most frequent agent isolated.<br /><strong>Conclusion:</strong> Despite preventive measures, urinary tract infections remain an important cause of morbidity and hospital admissions.<br /><strong>Keywords:</strong> Urinary Tract Infections; Postoperative Complications; Risk Factors; Kidney Transplantation; Portugal.

scholarly journals Evaluation of ESBL (Extended Spectrum Beta-Lactamase) Producing Escherichia Coli Isolated from Patients with Urinary Tract Infection by Phenotypic and Genotypic Methods

2020 ◽  
Author(s):  
Mohammad Hasan Namaei ◽  
Hengameh Hamzei ◽  
Marzie Moghanni ◽  
Azadeh Ebrahimzadeh
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Antibiotic Use ◽  
M Gene ◽  
Esbl Producer ◽  
Accurate Identification ◽  
E Coli ◽  
Tract Infections

Abstract Background: Urinary Tract Infection (UTI) is the most common bacterial infection in the world. E. coli is the predominant Pathogen. This study evaluates the prevalence of ESBL in E. colis isolated from patients with urinary tract infections with phenotypic and genotypic methods.Methods: This descriptive-analytical study was done on 155 isolates of E. coli isolated from patients with urinary tract infection who had received the study consent. After accurate identification of E. coli strains. ESBL production for Escherichia coli isolates which are resistant to ceftriaxone or ceftazidime was evaluated by CDT method. TEM, SHV and CTX-M genes were identified by PCR.Results: The results showed that 30 strains from 155 strains of E. coli had ESBL. Strains of ESBL producer were more in males was lower in educated persons. 38.9% of ESBL producer had antibiotic use, 29.9% -producing Escherichia hospitalization and 31.6% uti history. The highest level of drug allergy in the ESBL was related to nitrofurantoin, and the highest resistance was related to cefazolin, co-trimoxazole. The CTX-M and the CTX-M15 gene were found in 92.7% and 57.1% of cases, respectively; also the SHV and TEM genes were not found in any of ESBL-producing Escherichia coli strains. Most therapeutic response in patients was related to cefexime, ciprofloxacin and nitrofurantoin 27.4%, 26% 21.9%, respectively.Conclusion: This study showed that the history of antibiotic use, hospitalization, uti related to increase of ESBL-producing in E. coli isolates., the CTMX-M gene is the most common gene in ESBL-producing E. coli strains.

scholarly journals PhoU enhances the ability of extraintestinal pathogenic Escherichia coli strain CFT073 to colonize the murine urinary tract

Microbiology ◽  
2006 ◽  
Vol 152 (1) ◽  
pp. 153-160 ◽  
Author(s):  
Eric L. Buckles ◽  
Xiaolin Wang ◽  
C. Virginia Lockatell ◽  
David E. Johnson ◽  
Michael S. Donnenberg
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Mutant Strain ◽  
Human Urine ◽  
Type Strain ◽  
Wild Type Strain ◽  
Wild Type ◽  
Strain Cft073

The phoU gene is the last cistron in the pstSCAB–phoU operon and functions as a negative regulator of the Pho regulon. The authors previously identified a phoU mutant of extraintestinal pathogenic Escherichia coli strain CFT073 and demonstrated that this mutant was attenuated for survival in the murine model of ascending urinary tract infection. It is hypothesized that the PhoU protein might serve as a urovirulence factor by indirectly affecting the expression of virulence-related genes. In this study, the phoU mutant was further characterized and PhoU was confirmed as a virulence factor. Western blot analysis demonstrated that insertion of the transposon in the phoU gene disrupted the expression of PhoU. The phoU mutant had derepressed alkaline phosphatase activity under phosphate-excess and -limiting conditions. In single-challenge murine ascending urinary tract infection experiments, quantitative cultures of urine, bladder and kidney revealed no significant differences between the phoU mutant strain and the wild-type strain CFT073. However, in competitive colonization experiments, the phoU mutant strain was significantly out-competed by the wild-type strain in the kidneys and urine and recovered in lower amount in the bladder. Complementation of the phoU mutant with a plasmid containing the wild-type phoU gene restored the expression of PhoU and alkaline phosphate activity to wild-type levels and no significant difference in colonization was observed between the phoU mutant containing the complementing plasmid and wild-type in competitive colonization experiments. In human urine, the phoU mutant and wild-type grew comparably when inoculated independently, indicating that the attenuation observed was not due to a general growth defect. However, as observed in vivo, the wild-type out-competed the phoU mutant in competition growth experiments in human urine. These data indicate that PhoU contributes to efficient colonization of the murine urinary tract and add PhoU to a short list of confirmed urovirulence factors.

scholarly journals Loss of Regulatory Protein RfaH Attenuates Virulence of Uropathogenic Escherichia coli

2002 ◽  
Vol 70 (8) ◽  
pp. 4406-4413 ◽  
Author(s):  
Gábor Nagy ◽  
Ulrich Dobrindt ◽  
György Schneider ◽  
A. Salam Khan ◽  
Jörg Hacker ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Mouse Model ◽  
Type Strain ◽  
Wild Type Strain ◽  
Regulatory Protein ◽  
Wild Type ◽  
Serovar Typhimurium

ABSTRACT RfaH is a regulatory protein in Escherichia coli and Salmonella enterica serovar Typhimurium. Although it enhances expression of different factors that are proposed to play a role in bacterial virulence, a direct effect of RfaH on virulence has not been investigated so far. We report that inactivation of rfaH dramatically decreases the virulence of uropathogenic E. coli strain 536 in an ascending mouse model of urinary tract infection. The mortality rate caused by the wild-type strain in this assay is 100%, whereas that of its isogenic rfaH mutant does not exceed 18%. In the case of coinfection, the wild-type strain 536 shows higher potential to colonize the urinary tract even when it is outnumbered 100-fold by its rfaH mutant in the inoculum. In contrast to the wild-type strain, serum resistance of strain 536rfaH::cat is fully abolished. Furthermore, we give evidence that, besides a major decrease in the amount of hemin receptor ChuA (G. Nagy, U. Dobrindt, M. Kupfer, L. Emody, H. Karch, and J. Hacker, Infect. Immun. 69:1924-1928, 2001), loss of the RfaH protein results in an altered lipopolysaccharide phenotype as well as decreased expression of K15 capsule and alpha-hemolysin, whereas levels of other pathogenicity factors such as siderophores, flagella, Prf, and S fimbriae appear to be unaltered in strain 536rfaH::cat in comparison to the wild-type strain. trans complementation of the mutant strain with the rfaH gene restores wild-type levels of the affected virulence factors and consequently restitutes virulence in the mouse model of ascending urinary tract infection.

scholarly journals Prevalence of E. Coli in Urinary Tract Infection of Children Aged 1-15 Years in A Medical College of Eastern Nepal

2020 ◽  
Vol 58 (221) ◽  
Author(s):  
Arun Giri ◽  
Raju Kafle ◽  
Ganesh Kumar` Singh ◽  
Niraj Niraula
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Urinary Tract Infections ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Female Ratio ◽  
Presenting Symptoms ◽  
Tract Infections

Introduction: Urinary tract infection is one of the commonest causes of childhood morbidity. Earlydiagnosis and appropriate choice of antimicrobials is essential. Hence, this study aims to identify theprevalence of Escherichia coli in childhood urinary tract infections. Methods: This was a hospital based descriptive cross-sectional study conducted in Nobel MedicalCollege, Biratnagar over a period of one year. A total of 163 cases aged 1-15 years were included andclinical profile, laboratory reports including bacterial isolates in urine cultures and their sensitivitypatterns were documented. Results: The prevalence of Escherichia coli is 45 (53.57%) C.I. Escherichia coli was the most commonorganism isolated in bacterial cultures followed by Klebsiella 12 (14.29%), Enterococcus 10 (11.90%).Urinary tract infection was common among females with male: female ratio of 1:2.3. Fever 152(93.2%) and abdominal pain 113 (69.3%) were the most common presenting symptoms. Escherichiacoli was found most sensitive to Nitrofurantoin 43 (95.5%) followed by Ciprofloxacin 41 (91.1%) andAmikacin 40 (88.8%). Conclusions: Urinary tract infections in childhood require prompt attention and treatment to preventsignificant morbidity and mortality. From this study it can be concluded that Escherichia coli is oneof the most common isolates in urine culture and Aminoglycosides and Fluoroquinolones can beaccepted as empirical treatment regimens for childhood Urinary tract infections.

scholarly journals ANTIBIOTIC SUSCEPTIBILITY OF ESCHERICHIA COLI ISOLATE FROM URINARY TRACT INFECTION OF THALASSEMIC PATIENTS IN THI-QAR PROVINCE

2020 ◽  
Vol 28 (28) ◽  
pp. 22-33
Author(s):  
Alaa Abood Yasir OKAB ◽  
Manal B SALIH
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Clavulanic Acid ◽  
Rural Areas ◽  
Antibiotic Resistant ◽  
E Coli ◽  
Amoxicillin Clavulanic Acid ◽  
Tract Infections

Escherichia coli (E. coli) is the most common type of pathogen that causes Urinary tract infection disease. It can be presented as a pathogenic or non-pathogenic strain and found not only in the animal but also in the human intestine. This bacterium can cause opportunistic infection when the human host comprised of thalassemia patients or changes the healthy hemostatic flora. This study aimed to analyze the presence of bacteria in thalassemia patients with urinary tract infection. A total of 303 samples were collected during the period from August 2019 to January 2020 from thalassemia patients who suffered from urinary tract infection. The results showed that there were 6.9% of patients infected with E. coli, 2.6% of patients were infected with S. aureus, 0.7% with both Proteus and Klebsiella, while 89.1% of patients had a negative sample for bacteria. Also, the incidence of urinary tract infections in females is higher than in males. Besides, its occurrence in rural areas is higher than in city residents. Moreover, among 16 antibiotics tested to sensitize bacteria to antibiotics, Imipenem showed 100% efficacy on all isolated bacteria. In contrast, Netilmicin showed 80.1% efficacy, Gentamycin 80.1%, and Amikacin 76.2%. Ampicillin, Aztreonam, Amoxicillin-Clavulanic Acid, Tetracycline, and Ticarcillin-Clavulanic Acid, did not show any effectiveness toward the bacteria while other antibiotics showed different activities. Furthermore, the isolated microbes from thalassemia patients were the highest resistance to antibiotics in comparison with other studies, and this antibiotic-resistant may be due to the weakening of the patient's immune status and frequent blood taking and the antibodies it contains.

scholarly journals Prevalence of blaCTX-M, blaSHV, and blaTEM Genes in Escherichia coli Strains Isolated From Urinary Tract Infection Samples of Patients in the Intensive Care Unit in Qom, Iran

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Shima Sadat Lesani ◽  
Mohammad Soleimani ◽  
Pegah Shakib ◽  
Mohammad Reza Zolfaghari
Keyword(s):  
Escherichia Coli ◽  
Drug Resistance ◽  
Urinary Tract Infection ◽  
Intensive Care ◽  
Urinary Tract ◽  
Tract Infection ◽  
Intensive Care Units ◽  
Diffusion Method ◽  
E Coli ◽  
Tract Infections

Background: Escherichia coli is considered as one of the causes of opportunistic infections. Nowadays, due to the increase in drug resistance, the treatment of these infections has become very difficult and they are recognized as the main causes of death in hospitalized patients. Objectives: The aim of this study was to determine the prevalence of blaTEM, blaSHV, and blaCTX-M genes in E. coli strains isolated from the urinary tract infection in patients in Intensive Care Units of three different hospitals in Qom, Iran. Methods: This study was conducted in three months from October to December 2014. A total of 200 E. coli samples were taken from the patients with urinary tract infections in Intensive Care units of Qom hospital. The disc diffusion method was used to determine the susceptibility pattern of antibiotic and phenotypic confirmatory tests for screening of the expanded spectrum beta-lactamase (ESBL) isolates. The presence of blaTEM, blaSHV, and blaCTX-M genes was evaluated by the polymerase chain reaction (PCR) assay. Results: Of 200 samples, ampicillin (96%) and nitrofurantoin (19.5%) showed the highest and lowest drug resistance, respectively. A total of 156 isolates (78%) were identified as ESBLs using the phenotypic method. Moreover, 76 (38%), 90 (45%), and 123 (61.5%) isolates consisted of blaCTX-M, blaSHV, and blaTEM, respectively. Conclusions: Overall, the findings of this study showed that blaTEM was the most common gene with a frequency of 61.5% in ESBL E. coli.

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