Abstract
Biotype and serotype were determined for 359 isolates of H. influenzae(Hi) to define relation to virulence and antibiotic resistance. Of 61 patients with Hi isolates from invasive sites 95% were serotypable(S+) and 79% were biotype(B)I. 87% of cases of Hi meningitis, cellulitis, bacteremia and arthritis were caused by BI;50% of epiglottitis and pneumonia were. All 71 isolates from inflamed conjunctivae were not serotypable(S-);83% were B II or III;only 8% were BI. Frequency and biotype of conjunctival Hi did not differ with age or season. 147 children with Hi respiratory isolates were grouped according to illness and probable pathogenic role of Hi. 90% of respiratory isolates were S-. Group 1(well or ill, Hi not related)had no S+ isolates and only 7% were BI. Group 2(ill, Hi possibly/probably related)had significantly more S+(17%)and BI(35%). Group 3(cystic fibrosis patients)also had significantly more S+(23%)and BI(45%). Ampicillin resistance of respiratory isolates was similar for all groups. Otitis media(Hi middle ear isolate)was significantly associated with BI(8/13,61%) but not S+(1/13). Ampicillin resistance of Hi(any source-299 patients)was greater in S-(18%)than in S+(10%)strains. Resistance varied significantly with biotype;(By highest(46%) and BI lowest (10%). In summary serotype positive Hi was associated with invasive disease. Biotype I Hi(serotype positive and negative)was associated with invasive disease, otitis media, and cystic fibrosis but had least resistance to ampicillin.
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Long, S., Jeter, M. & DiGeorge, A. 1042 HEMOPHILUS INFLUENZAE BIOTYPE PREDICTS VIRULENCE. Pediatr Res 15 (Suppl 4), 616 (1981). https://doi.org/10.1203/00006450-198104001-01068
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DOI: https://doi.org/10.1203/00006450-198104001-01068