Abstract
During an outbreak of ampicillin-resistant H. influenzae type B (AR-HITB) in a children's chronic care facility, the carriage rates of AR-HITB and ampicillin-sensitive H. influenzae type B (AS-HITB) were studied. Multiple culture surveys were done with 27 to 32 children cultured. As many as 81% carried AS-HITB and as many as 48% carried AR-HITB. Using special media (chocolate agar with 2 mcg/ml of ampicillin), we found that 30% of the patients carried both strains. Eradication of both strains was attempted by administering trimethoprim-sulfamethoxazole (TMP-SMX) (8 mg/40 mg) for five days to all individuals on the ward. At the end of therapy, AS-HITB carriage had been reduced by 80%. AR-HITB were not eradicated from any carrier. Doubling the dose and duration of therapy with TMP-SMX similarly had no effect on AR-HITB carriage. Agar dilution susceptibility studies revealed trailing end points for the majority of AR-HITB isolates. Nearly all AS-HITB isolates had sharp end points. These data suggest that: 1.) TMP-SMX appears to be effective in eradicating nasopharyngeal carriage of AS-HITB; 2.) This drug combination is not effective for AR-HITB carriage; and 3.) Trailing end points on in vitro agar dilution tests may provide evidence for in vivo resistance of AR-HITB to TMP-SMX.
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Yogev, R., Lander, H., Davis, A. et al. 389 PERSISTENCE OF AMPICILLIN-RESISTANT HAEMOPHILUS INFLUENZAE TYPE B IN THE NASOPHARYNX AFTER ERADICATION OF AMPICILLIN-SENSITIVE HAEMOPHILUS INFLUENZAE TYPE B BY TRIMETHOPRIM-SULFAMETHOXAZOLE. Pediatr Res 12 (Suppl 4), 428 (1978). https://doi.org/10.1203/00006450-197804001-00394
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DOI: https://doi.org/10.1203/00006450-197804001-00394