Ampicillin-resistant Haemophilus influenzae colonizing ambulatory children
D. W. Scheifele and S. J. Fussell
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.
