Ocorrência de Escherichia coli comensal e diarreiogênica na microbiota fecal de crianças com e sem diarréia aguda e seu perfil de susceptibilidade a antimicrobianos

Abstract

Acute diarrhea is a public health problem, important cause of morbidity and mortality, especially in developing countries. The etiology is varied and considering the bacterial pathogens, the diarrheagenic Escherichia coli pathotypes are among the most important. In this study we have investigated the occurrence of commensal or diarrheagenic E. coli in 141 fecal samples from children of zero to five years of age in Juiz de Fora, MG. Of the specimens, 84 were obtained from clinically injured donors with acute diarrhea (CD) and 57 from clinically healthy donors without diarrhea (SD). After microbial identification and characterization the bacterial antimicrobial susceptibility patterns were determined. The bacterial strains were phenotipically and genotipically indentified by conventional biochemical methods and molecular approach, respectively. The E. coli pathotypes were also genetically characterized by molecular methodology. The antimicrobial susceptibility patterns were determined by the Kirby-Bauer method, according to the CLSI guidelines (2007). Considering all fecal specimens, 136 E. coli strains were isolated and identified (36.8%, CD) and 84 (30.9%, SD). Confirmation of identification by molecular approach showed 97,3% of correlation between the two methodologies. Enteroaggregative E. coli (EAEC) was the most frequently recovered pathotype identified in the acute diarrhea group (16.2%) whereas the only recovered pathotype identified in the feces from healthy donors (30.9%). Enteropathogenic E. coli (EPEC) was the second most isolated pathotype group (10.3%), followed by STEC (7.4%) and ETEC (2.9%). No typical EPEC or EIEC strains were recovered. The antimicrobial susceptibility patterns shown high antimicrobial resistance rates against ampicillin, tetracycline, and sulfamethoxazole-trimethoprim. Intermediary resistance was observed against ampicillin/sulbactam, cefalotin, tetracycline, amikacin and gentamicin. The most effective antimicrobials were ceftazidime ceftriaxone, imipenem and piperacillin/tazobactam, for which no bacterial resistance was observed. The differentiation between the diarrheagenic E. coli pathotypes is of great importance, since they are involved in acute diarrheal diseases in children and, almost often will require antimicrobial chemotherapy. Overall, our results may indicate the importance of the bacterial agents in the etiology of diarrheic diseases in childhood, mainly considering children of 0 to 5 years. The high antimicrobial resistance observed in our study raises a broad discussion on the indiscriminate or improper use of antimicrobials, besides the risks of self-medication.