[Antibiotic resistance and serotypes of Streptococcus pneumoniae in Zurich (1984-1985)].

We have investigated the serotypes and sensitivity of 133 pneumococci against 11 antimicrobial agents in the agar dilution test. The strains had been isolated from clinical specimens sent to the Department of Medical Microbiology of the University of Zurich during 1984 and 1985. - Three strains (2.3%) had reduced sensitivity to penicillin G. 23 strains (17.3%) showed resistance or reduced susceptibility to tetracycline, one strain each (0.8%) to amoxycillin and cefaclor, and two strains each (1.5%) to erythromycin and sulfamethoxazole/trimethoprim. All pneumococcal strains investigated were susceptible to ceftazidime, ceftriaxone, chloramphenicol, vancomycin and ciprofloxacin. In view of this situation, routine testing of all clinically significant pneumococci is to be recommended. However, in the agar diffusion test the use of a penicillin G disk is unreliable and may give results with false sensitivity. Therefore, the susceptibility test should be performed with a disk containing oxacillin. - The prevalent capsular serotypes were - in descending order - types 3, 6, 23, 19, 14, 7, 8, 9, 1, and 17. 90.2% of the isolated pneumococci belonged to serotypes which are contained in the new vaccine "Pneumovax-23".