Antibiotic resistance amongst various types of Haemophilus species

Antibiotic resistance of haemophili was studied as part of an epidemiological survey on the distribution of biotypes of Haemophilus influenzae and H. parainfluenzae from various clinical isolates. Biotype II H. influenzae was the commonest biotype isolated but biotype III yielded the most frequent antibiotic resistance. Resistance to ampicillin (15.1%) was commonest, followed by sulphonamide, tetracycline, trimethoprim and chloramphenicol. Multi-resistant strains were found including one capsular type b (biotype III) strain. H. parainfluenzae biotype I was the commonest isolate but biotype II was most frequently resistant to antibiotics. The resistance pattern followed that of H. influenzae except for chloramphenicol to which resistance was commoner than for trimethoprim.