ABSTRACT
ABSTRACT: This study identified the virulence genes, pathovars, and phylogenetic groups of Escherichia coli strains obtained from the feces of dogs with and without diarrhea. Virulence genes and phylogenetic group identification were studied using polymerase chain reaction. Thirty-seven E. coli isolates were positive for at least one virulence factor gene. Twenty-one (57.8%) of the positive isolates were isolated from diarrheal feces and sixteen (43.2%) were from the feces of non-diarrheic dogs. Enteropathogenic E. coli (EPEC) were the most frequently (62.2%) detected pathovar in dog feces and were mainly from phylogroup B1 and E. Necrotoxigenic E. coli were detected in 16.2% of the virulence-positive isolates and these contained the cytotoxic necrotizing factor 1 (cnf1) gene and were classified into phylogroups B2 and D. All E. coli strains were negative for the presence of enterotoxigenic E. coli (ETEC) enterotoxin genes, but four strains were positive for ETEC-related fimbriae 987P and F18. Two isolates were Shiga toxin-producing E. coli strains and contained the toxin genesStx2 or Stx2e, both from phylogroup B1. Our data showed that EPEC was the most frequent pathovar and B1 and E were the most common phylogroups detected in E. coli isolated from the feces of diarrheic and non-diarrheic dogs.
RESUMO: Este estudo pesquisou genes de virulência, patovares e grupos filogenéticos de amostras de E. coli isoladas de fezes de cães com e sem diarreia. Os genes de virulência e a identificação de grupos filogenéticos foram estudados pela técnica de reação em cadeia da polimerase (PCR). 37 isolados de E. coli foram positivos para pelo menos um fator de virulência na análise de PCR. Destes, 21 (57,8%) foram isolados de fezes de cães com diarreia e 16 (43,2%) de fezes de cães não diarreicos. E. coli enteropatogênica (EPEC) (23/37, 62,2%) foi o patovar mais frequente detectado em fezes de cães e foram classificados principalmente como filogrupos B1 e E. E. coli necrotoxigênica (NTEC) positivos para CNF1 foram detectados (6/37, 16,2%) e classificados como B2 e D. Todas as amostras de E. coli foram negativas quanto à presença de genes de enterotoxinas de E. coli enterotoxigênica (ETEC), mas quatro amostras foram positivas para fimbrias relacionadas ao ETEC, 987P (2) e F18 (2). As amostras de E. coli (STEC) produtora de toxina Shiga foram positivas para a toxina Stx2 (1/37) e Stx2e (1/37), ambas do filogrupo B1. Nossos resultados indicaram que EPEC foi o patovar mais frequente e B1 e E foram os filogrupos mais comuns detectados em amostras E. coli isoladas de fezes de cães diarreicos e não diarreicos.
ABSTRACT
Context: The increased rate of infection by New Delhi metallo-beta-lactamases-1 (NDM1) producing Escherichia coli is a major concern since they show a high rate of drug resistance and are responsible for mortality and morbidity. Aims: To characterize the NDM1 producing E. coli isolates and their impact on patients’ clinical outcome. Settings and Design: This descriptive study was carried out in a multi-specialty tertiary care hospital. Materials and Methods: Three hundred nonrepeat strains of E. coli from inpatients were included in the study. Modifi ed Hodge test and metallo-beta-lactamases (MBL) e-test were performed to detect carbapenemase and MBL activity. Polymerase chain reaction (PCR) technique was performed to detect NDM1. NDM1 positive isolates were further tested for plasmid mediated AmpC, blaCTX, blaSHV, blaTEM genes and also for phylogrouping by PCR methods. Treatment and patients’ clinical outcome were also analyzed. Results: Out of 300 isolates, 21 (7%) were MBL producers by phenotypic methods. Of this, 17 (81%) were NDM1 positives, among the NDM1 producers 6 (35%) isolates were belongs to phylogroups D followed by A 5 (29%), B1 4 (24%) and B2 2 (12%), 15 (88%) isolates were blaCTX-M positive suggestive of extended-spectrum beta lactamase producing strain and 7 (47%) were positive with CIT type of AmpC. With the follow-up of the patients, it was found that 12 (71%) recovered and 3 (18%) developed relapses, and mortality was seen in 2 (12%) patients. Conclusions: NDM1 producing isolates showed a high degree of drug resistance but can be treated with suitable antimicrobials, in the majority. Early detection and choice of appropriate antibiotics may help in reducing mortality and morbidity.