title: Ampicillin-resistant Haemophilus influenzae colonizing ambulatory children.
abstract: The prevalence of ampicillin sodium-resistant Haemophilus influenzae was determined from throat cultures of 305 ambulatory children. Resistant strains were detected in 3% of children, amounting to 12% of Haemophilus isolates. Factors associated with carriage of ampicillin-resistant strains were sought: only ampicillin exposure was significant. Among children who had received ampicillin or amoxicillin trihydrate within six months, 9% harbored ampicillin-resistant strains compared with 1.4% among those not exposed. Colonization with H influenzae was more frequent following the use of ampicillin, and a higher proportion of isolates was resistant rates was observed with other antibiotics or with factors such as age, sex, otitis history, or day-care center exposure. The association between ampicillin/amoxicillin usage and carriage of ampicillin-resistant strains is increasingly clear. It remains to be determined whether the use of newer antibiotics for otitis also will encourage the development of resistance in H influenzae.
mesh_terms: D000553:Ambulatory Care; D000667:Ampicillin / Q000494:pharmacology*; D002353:Carrier State / Q000382:microbiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006192:Haemophilus Infections / Q000188:drug therapy / Q000382:microbiology*; D006193:Haemophilus influenzae / Q000187:drug effects*; D006801:Humans; D007223:Infant; D008297:Male; D009305:Nasopharynx / Q000382:microbiology; D010033:Otitis Media / Q000188:drug therapy*; D010403:Penicillin Resistance
chemical_list: D000667:Ampicillin