ANTIMICROBIAL RESISTANCE AMONG BACTERIAL ISOLATES FROM CHILDREN

Antimicrobial resistance patterns were studied in isolates from children hospitalized with respiratory tract infections in Mexico City and Cuernavaca, Morelos, Mexico, and from healthy children attending a day-care center in Cuernavaca. All the children were aged <5 years. We determined the in vitro susceptibilities of 294 isolates to antimicrobial agents of potential use in the treatment of diseases caused by Haemophilus influenzae (56 strains from the hospitalized patients and 82 from the healthy children), Streptococcus pneumoniae (39 from patients and 44 from healthy children), and Moraxella catarrhalis (16 from patients and 57 from healthy children). Thirty-four (25%) of the H influenzae strains (17 were type b) produced beta-lactamase and were thus resistant to ampicillin. Forty-eight (58%) of the S pneumoniae isolates were resistant to one or more antimicrobials. Serotypes or serogroups 6A/6B, 23F, 14, 19, and 15 were most prevalent. Fifty-three (73%) of the M catarrhalis strains were resistant to ampicillin, 48 (66%) were resistant to cefaclor, and a few were resistant to trimethoprim/sulfamethoxazole or cefotaxime; they were, however, susceptible to the other antimicrobials tested. The results indicate that changes can occur in the susceptibility of these pathogens and that selective susceptibility testing and epidemiologic studies in hospitalized patients and children in day-care centers are necessary.