Third generation cephalosporin-resistant gram-negative bacilli in the feces of hospitalized children.

In view of the widespread use of third generation cephalosporins in hospitalized infants, we attempted to determine whether their use was associated with the emergence of resistance in fecal Gram-negative bacilli. Stools from infants hospitalized for varying durations were cultured on MacConkey agar containing 4 micrograms/ml of cefotaxime. All isolates growing on this medium were identified and their susceptibilities to 29 antimicrobial agents were determined. Sixty-five infants were studied of whom 44 were receiving a third generation cephalosporin, 7 another antibiotic and 14 no antibiotic. Thirty-one strains resistant to third generation cephalosporins (minimal inhibitory concentrations > or = 16 micrograms/ml) to cefotaxime, ceftriaxone or ceftazidine) were isolated from 26 infants. The proportions of infants with resistant strains were not significantly different whether they were: (1) receiving a third generation cephalosporin or not; (2) hospitalized for longer or shorter than 2 days or not; (3) older or younger than 3 months or not. Notably 8 infants harbored resistant strains within 24 hours of admission. The commonest resistant strains isolated belonged to the genera Enterobacter (10), Citrobacter (6), Serratia (3), Cedecea (3) and Chromobacterium (3). In conclusion hospitalized infants had a high incidence of fecal colonization with Gram-negative bacilli resistant to third generation cephalosporins. These bacteria were predominantly those known to produce broad spectrum beta-lactamases. This colonization was not necessarily associated with the infant receiving such antibiotics or with prolonged hospitalization.