[Haemophilus influenzae isolated in Switzerland: antibiotic sensitivity and biotyping]

208 H. influenzae (HI) strains originating from the whole of Switzerland have been analysed for capsular serotype, biotype, and susceptibility to the following antibiotics: ampicillin, chloramphenicol, tetracycline, co-trimoxazole, and ceftriaxone. Serotype b is the commonest of the encapsulated strains. Biotypes II and III (respiratory tract) and I (invasive diseases) are the biotypes most encountered. Ceftriaxone is the most active among the antibiotics tested: 0.03 microgram inhibits 100% of strains, whether penicillinase producers (PP) or not. To evaluate the rate of resistant HI in Switzerland, 1883 isolates, 206 of which originated from invasive diseases (meningitis, epiglottitis, septicemia) have been considered. The PP rate is about 4%, irrespective of the group considered. Among the isolates from the invasive diseases, 3 were resistant to chloramphenicol, and 1 to ampicillin and chloramphenicol. The value of 4% for the PP strains is not very high; however, because of its powerful antibacterial activity and its high penetration into the cerebrospinal fluid, it seems reasonable to consider the use of a third generation cephalosporin, such as ceftriaxone, for the early treatment of meningitis in infants. If such a drug is indicated as a first-choice antibiotic for this meningitis it should be confined to this use only, to avoid the emergence of resistant strains.