Antibiotic sensitivity of Haemophilus influenzae, Streptococcus pneumoniae, Streptococcus pyogenes and Branhamella catarrhalis isolated from upper respiratory tract infections in Sweden.

Isolates of Haemophilus influenzae, Streptococcus pneumoniae, Streptococcus pyogenes and Branhamella catarrhalis were collected from five laboratories in different geographical areas in Sweden. Nine hundred and fortyfour strains were tested by the agar dilution method for susceptibility to seven oral antibiotics: phenoximethylpenicillin, ampicillin, cefaclor, erythromycin, doxycycline, trimethoprim-sulfamethoxazole and chloramphenicol. The H. influenzae and B. catarrhalis strains were also tested for beta-lactamase production. Of the H. influenzae strains, 8% were beta-lactamase-producing, while 35% of B. catarrhalis strains produced beta-lactamase. The latter value is higher than has earlier been reported in Sweden. Five S. pneumoniae strains showed decreased sensitivity to penicillin, and 9.5% of the S. pneumoniae strains showed a decreased sensitivity to one or more of the seven antibiotics tested. The S. pyogenes strains were sensitive to all the antibiotics tested with the exception of 4% of the strains, which showed a decreased sensitivity to doxycycline.