Antibiotic susceptibility pattern and capsular types of Haemophilus influenzae recovered from clinical specimens in northern Norway.

One hundred and nine strains of Haemophilus influenzae recovered from clinical specimens were examined for antibiotic sensitivity pattern and capsular types. All strains from blood cultures, cerebrospinal fluid and a joint aspirate were type b whereas most of the isolates were acapsular when recovered from other specimens viz. wound secretions (67%), maxillary sinus (75%), lower resp tract (86%), nasal cavity (90%). Out of the 109 strains 88 (81%) were non-typable, and 3.6% were beta-lactamase-producing, two of which were type e, one was type b and one was acapsular. Three beta-lactamase-producing strains were isolated from specimens from the respiratory tract and one from blood cultures. Beta-lactamase-producing strains including one chloramphenicol-resistant strain harboured similar plasmids, as judged by agarose gel electrophoresis. The strains showed quite a uniform sensitivity to antibacterial agents with the exception of sulphonamides to which the capsular strains, particularly type b strains, were less susceptible.