[Diarrhea outbreak and bacterial resistance to ampicillin in newborns].

Twenty-eight healthy neonates from the San Juan de Dios Hospital were studied to determine the pattern of antibiotic resistance of indigenous intestinal bacteria. Sixty-eight per cent of infants had enterobacteriaceae resistant to several wide-spectrum antibiotics, including ampicillin; 28 per cent of the cultures had plasmid-mediated ampicillin resistance. In the course of the study, an outbreak of 10 acute cases of diarrhea occurred, not associated to any of the commonly known agents, including the rotaviruses. Enterobacteriaceae multiple resistant were isolated from all cases; ampicillin-resistant strains were found in all; those resistances were mediated by transmissible plasmids. Several sites of the Neonatology Ward were sampled and two yielded E. coli with resistance to 8 drugs transmissible in vitro. The outbreak was controlled after strict hygienic measures were established in the ward. A following sample showed a decrease in indigenous antibiotic-resistant strains, especially E. coli; however, plasmid mediated resistant Klebsiella was still isolated several months later. The need to regulate the use of antibiotics; to educate the medical personnel and the public in general and to modify the hospital norms and regulations are discussed in the paper.