ABSTRACT
Abstract INTRODUCTION: Nosocomial and community acquired urinary tract infections (UTIs) are one of the most encountered infections in the world. METHODS: This study aimed to determine the antibiotic susceptibility, phylogeny, and virulence genes of 153 Escherichia coli strains isolated from UTIs. Antimicrobial susceptibility of the isolates to different classes of antimicrobials was determined by the VITEK-2 automated system. Presence of virulence genes and phylogenetic groups were investigated by PCR. RESULTS: Regarding susceptibility to antimicrobials, ampicillin resistance was most abundant (67.3%), followed by amoxicillin-clavulanic acid (50.9%); least abundant was resistance to amikacin (1.3%) and nitrofurantoin (1.3%). Multi drug resistance (MDR) was observed in 34.6% of the isolates, and all isolates were found to be susceptible to imipenem, meropenem and fosfomycine. The majority of the isolates belonged to the phylogenetic group B23 (35.9%), followed by A1 (20.9%), D1 (18.9%), D2 (12.4%), A0 (%5.9), B1 (3.9%) and B2 (1.9%). Among E. coli strains examined, 49% had iucD, 32.7% papE-F, 26.1% papC, 15% cnf2, 11.1% sfa, 7.8% cnf1, 1.3% afaE, 1.3% afaD, 1.3% hlyA, 0.7% f17a-A, 0.7% clpG and 0.7% eaeA genes. CONCLUSIONS Our research demonstrated that virulence factors were distributed among different phylogroup/subgroups, which play a role in UTIs pathogenesis in humans. For this reason, complex and detailed studies are required to determine the relationship between virulence factors and specific E. coli strains that cause UTIs in humans.
Subject(s)
Humans , Urinary Tract Infections/microbiology , Virulence Factors/genetics , Escherichia coli/drug effects , Escherichia coli/genetics , Escherichia coli Infections/microbiology , Anti-Bacterial Agents/pharmacology , Phylogeny , RNA, Ribosomal, 16S , Microbial Sensitivity Tests , Polymerase Chain Reaction , Escherichia coli/isolation & purification , GenotypeABSTRACT
ABSTRACT: This study aimed to determine the virulence factors, phylogenetic groups, and the relationships between pathovars and phylogenetic groups of E. coli strains isolated from feces of buffalo calves. A total of 217 E. coli strains were obtained from feces after culture and were screened by PCR for detection of virulence factors EAST-1, enterohemolysin, Saa, CNF2, F41, F5, STa, intimin, Stx1 and Stx2. One hundred and thirty-four isolates were positive for one or more virulence factors: eighty-four from diarrheic animals, and fifty from non-diarrheic calves. The pathovars of E. coli identified in diarrheic feces were ETEC (F5+) (2/84), NTEC (16/84), STEC (20/84), EPEC (3/84), EHEC (3/84), and EAEC (EAST-1+) (33/84). Pathovars identified in non-diarrheic animals were NTEC (21/50), STEC (17/50), EHEC (1/50) and EAEC (7/50). E. coli strains positive for EAST-1 (P=0.008) and phylogroup C (P = 0.05) were associated with the presence of diarrhea. Phylogenetic analysis showed that 58.95% of the isolates belonged to phylogroup B1, followed by E (9.70%), B2 (5.90%), C (5.90%), D (5.22%), A (2.24%), and F (1.50%). Phylogroup B1 predominated in pathogenic E. coli isolated from water buffalo, and phylogroup C constituted an enteropathogenic E. coli for water buffalo calves.
RESUMO: O objetivo foi determinar os fatores de virulência, os grupos filogenéticos e as possíveis relações entre os patovares e os grupos filogenéticos identificados de cepas de Escherichia coli isoladas de fezes de bezerros bubalinos. Um total de 217 amostras de E. coli foram identificadas a partir de cultura das fezes e submetidas a reação em cadeia da polimerase (PCR) para detecção dos fatores de virulência EAST-1, enterohemolisina, Saa, CNF2, F41, F5, STa, intimina, Stx1 e Stx2. Foram identificadas 134 cepas positivas para um ou mais fatores de virulência: 84isoladas de bezerros bubalinos diarreicos e 50 de bezerros bubalinos saudáveis. Os patovares de E. coli obtidos de fezes diarreicas foram ETEC (F5+) (2/84), NTEC (16/84), STEC (20/84), EPEC (3/84), EHEC (3/84), e EAEC (EAST-1+) (33/84). Os patovares isolados de fezes não diarreicas foram NTEC (21/50), STEC (17/50), EHEC (1/50) e EAEC (7/50). Cepas de E. coli positivas para EAST-1 (P = 0,008) e filogrupo C (P = 0,05) foram associadas com a presença de diarreia. A análise de filogrupos revelou que 58,95% dos isolados pertencem ao filogrupo B1, seguido por E (9,70%), B2 (5,90%), C (5,90%), D (5,22%), A (2,24%) e F (1,50%). O filogrupo B1 predomina em cepas de E. coli patogênicas isoladas de bezerros búfalos e o filogrupo C constitui um filogrupo de E. coli patogênica entérica para bezerros.
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Extraintestinal pathogenic Escherichia coli (ExPEC), the specialized strains ofE.coli that cause most extraintestinal infections, represent a major but littleappreciated health threat. Phylogenetic analysis has shown that ExPEC is composedof four main phylogenetic groups (A,B1, B2, and D) and that virulent extraintestinalstrains mainly belong to groups B2 and D.In this study, we aimed to assess therelation between adherence virulence and phylogenetic groups of ExPEC.A total of 161 E.coli samples were collected. Out of these 17 (10.6%) werefrom pus, 66 (41 %) from urine, 78 (48.4%) from cervical swab. The phylogeneticgroups and 6 virulence genes (fimH, papC, papGII, papGIII, fa/draBC,andSfa/focDE) encoding adhesins were identified by triplex PCR. Phylogeneticgroups distribution was as follows: B1 10.5%, A 24.7%, B2 25.3%, and D 38.9%. Virulence genes prevalence was fimH 90.1%, papC 23%, papGII 16.8%, papGIII1.9%, Afa/draBC 11.8%, andSfa/focDE 5.6%. The cell surface protein (curli) wasdetected 50,3% by Congo red agar. In conclusion: The most isolated strainsbelonged to the phylogenetic group B2 and D. The phylogenetic groups weresignificantly associated with some genes encodingadhesins (fimH, papC) and cellsurface protein (curli).
ABSTRACT
Extraintestinal pathogenic Escherichia coli (ExPEC), the specialized strains ofE.coli that cause most extraintestinal infections, represent a major but littleappreciated health threat. Phylogenetic analysis has shown that ExPEC is composedof four main phylogenetic groups (A,B1, B2, and D) and that virulent extraintestinalstrains mainly belong to groups B2 and D.In this study, we aimed to assess therelation between adherence virulence and phylogenetic groups of ExPEC.A total of 161 E.coli samples were collected. Out of these 17 (10.6%) werefrom pus, 66 (41 %) from urine, 78 (48.4%) from cervical swab. The phylogeneticgroups and 6 virulence genes (fimH, papC, papGII, papGIII, fa/draBC,andSfa/focDE) encoding adhesins were identified by triplex PCR. Phylogeneticgroups distribution was as follows: B1 10.5%, A 24.7%, B2 25.3%, and D 38.9%. Virulence genes prevalence was fimH 90.1%, papC 23%, papGII 16.8%, papGIII1.9%, Afa/draBC 11.8%, andSfa/focDE 5.6%. The cell surface protein (curli) wasdetected 50,3% by Congo red agar. In conclusion: The most isolated strainsbelonged to the phylogenetic group B2 and D. The phylogenetic groups weresignificantly associated with some genes encoding adhesins (fimH, papC) and cellsurface protein (curli).
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Context: Plasmid mediated AmpC (pAmpC) β-lactamase producing Escherichia coli are an emerging problem worldwide as they are now exhibiting resistance to multiple classes of antibiotics and are a major cause of therapeutic failure. Aims: The aim of this study was to characterize pAmpC β-lactamase producing extraintestinal E. coli, their phylogenetic distribution, resistance pattern, treatment options, and impact on patient’s clinical outcome. Settings and Design: This descriptive study was carried out in a multi-specialty tertiary care hospital. Materials and Methods: A total of 300 clinically signifi cant, non-repeat isolates were studied. AmpC disk test was used for phenotypic AmpC-β- lactamase detection. Molecular types of pAmpC were determined by a multiplex polymerase chain reaction (PCR). Phylogenetic analysis was performed by triplex PCR methods. Metallo-beta-lactamase (MBL) detection was done by E test. Antibiogram, treatment, and clinical outcome were collected in a structured proforma. Results: Although 95 isolates (32%) were phenotypically positive for AmpC, PCR detected CIT type of AmpC gene in only 37 isolates. Majority of strains were from phylogroup A (85%) and B1 (58%) which are considered as commensal groups. Co-production of ESBL’s was observed in 33 strains and 5 strains were found to be MBL producers. Most widely prescribed antibiotics were 3rd generation cephalosporins (30%), carbapenems (19%) and aminoglycosides (16%). Conclusions: Plasmid mediated AmpC producing isolates were found to exhibit a high degree of drug resistance, and they mainly belonged to commensal strains possibly due to misuse of antibiotics. Proper antibiotic policy is required to limit the spread of pAmpC producers or else it will lead to a therapeutic dead end in the near future.
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BACKGROUND: This study was designed to characterize urinary isolates of Escherichia coli that produce extended-spectrum beta-lactamases (ESBLs) and to determine the prevalence of other antimicrobial resistance genes. METHODS: A total of 264 non-duplicate clinical isolates of E. coli were recovered from urine specimens in a tertiary-care hospital in Busan in 2005. Antimicrobial susceptibility was determined by disk diffusion and agar dilution methods, ESBL production was confirmed using the double-disk synergy (DDS) test, and antimicrobial resistance genes were detected by direct sequencing of PCR amplification products. E. coli isolates were classified into four phylogenetic biotypes according to the presence of chuA, yjaA, and TSPE4. RESULTS: DDS testing detected ESBLs in 27 (10.2%) of the 264 isolates. The most common type of ESBL was CTX-M-15 (N=14), followed by CTX-M-3 (N=8) and CTX-M-14 (N=6). All of the ESBL-producing isolates were resistant to ciprofloxacin. PCR experiments detected genes encoding DHA-1 and CMY-10 AmpC beta-lactamases in one and two isolates, respectively. Also isolated were 5 isolates harboring 16S rRNA methylases, 2 isolates harboring Qnr, and 19 isolates harboring AAC(6')-Ib-cr. Most ESBL-producing isolates clustered within phylogenetic groups B2 (N=14) and D (N=7). CONCLUSION: CTX-M enzymes were the dominant type of ESBLs in urinary isolates of E. coli, and ESBL-producing isolates frequently contained other antimicrobial resistance genes. More than half of the urinary E. coli isolates harboring CTX-M enzymes were within the phylogenetic group B2.