Serotypes and biotypes and antibiotic susceptibility of Haemophilus influenzae encountered in a clinical laboratory in Taiwan.

Forty-four serologically and biochemically typable Haemophilus influenzae isolates from clinical specimens in Taiwan were subjected to analysis in their relationship with source of isolation and age distribution. It was found that all isolates from blood and cerebrospinal fluid were serotype b, biotype I, and all were in children less than 4 years of age. Serotypes b and e, biotypes I and III were encountered to have the highest incidence of infection caused by H. influenzae in this area. All H. influenzae isolates were further tested for susceptibility to several selected antibiotics. All strains of this organism were susceptible to erythromycin and chloramphenicol. All but two strains were susceptible to tetracycline, whereas more strains were resistant to carbenicillin, gentamycin, keflin, and penicillin. Thirty-four percent strains were found to be resistant to ampicillin and all were beta-lactamase producer. No direct correlation between ampicillin resistance and serotypes or biotypes was recognized.