RESUMEN
OBJECTIVE: To determine the rate of antibiotic resistance of fecal E. coli from healthy children and to infer if it is acquired environmentally or induced by antibiotic use. MATERIAL AND METHODS: Cross sectional study in children from schools and day care centers in Leon, Mexico. Prior antibiotic use (60 days) was questioned to the parents. A single fecal sample was cultured and an isolated colony suggestive of E. coli was submitted to biochemical identification and testing of disk susceptibility to 12 antibiotics. RESULTS: Four hundred fifty-six isolates were studied from children of 10 institutions, with ages ranging from 3 to 72 months (mean, 42.41). Use of antibiotics was referred in 242 children (53.07). The antibiotics more commonly used were trimethoprim/sulfa, ampicillin, and penicillin (34, 20.5, and 18). The highest rate of resistance was found for tetracycline, ampicillin, and trimethoprim/sulfa (64.4, 52.63, and 46.05). The resistance to ciprofloxacin, amikacin, gentamicin, and ceftriaxone was less than 5. Resistance to five or more antimicrobials was found in 93 isolates (20.39); this rate was higher in isolates from children who received antibiotics (59/242, 24.38 vs. 34/214, 15.89) (p = .025; OR 1.71, IC 95 1.04-2.81). CONCLUSIONS: The study suggests that saprophyte bacteria acquires resistance through both, use of antibiotics and from the environment. These results support the concept that antimicrobial resistance must be considered as a public health problem.