Ocorrência,detecção de linhagens enterotoxigênicas e perfil de susceptibilidade a antimicrobianos de anaeróbios do grupo Bacteroides fragilis na microbiota fecal de crianças apresentando ou não diarréia aguda em Juiz de Fora

Abstract

Clinical conditions in the gastrointestinal tract such as acute diarrhea are one of the major causes of death in children. Species of Bacteroides fragilis group are important constituents of the intestinal microbiota. Its importance is recognized as the etiologic agent of endogenous infections associated with gastrointestinal tract and other sites. Our objective was to evaluate the occurrence and distribution of species of B. fragilis group in fecal samples of children with and without diarrhea, their antimicrobial susceptibility patterns and to investigate enterotoxigenic strains. We analyzed 175 fecal samples from children presenting (n = 110) or not (n = 65) clinical manifestations in the gastrointestinal tract, with an average of 2 years of age, obtained in Juiz de Fora, MG. The samples were evaluated by biochemical-physiological and molecular (PCR-Multiplex) methods. The drug susceptibility patterns were determined by the agar dilution method according to CLSI. Of the isolates were identified 47 bacterial strains representative of B. fragilis group. By the biochemical-physiological methodology, 8 species of the group were identified and 4 were identified by the molecular genetics technique. In 58.3% of the fecal samples, B. fragilis group were detected by the Multiplex - PCR. Enterotoxigenic strains were detected in 4.6% of fecal specimens, of which 3.7% in the diarrheic and 6.15% in the control samples. Antimicrobial resistance was observed against all tested drugs (ampicillin, ampicillin/sulbactam, piperacillin/tazobactam, meropenem, ceftriaxone, clindamycin and chloramphenicol), although the most effective drugs were ampicillin/sulbactam and piperacillin/tazobactam. The results showed that the B.fragilis group is prevalent in the fecal microbiota of children in Juiz de Fora, however, at higher levels in feces from health donors than in diarrheic samples. The molecular methodology was more effective in identifying microbial strains when compared to the biochemical and physiological techniques. The high levels of resistance observed raise thoughts about the indiscriminate use of antimicrobials. Prospective studies are needed to gain a better understanding on the role of these bacteria in acute diarrhea in children.