The distribution of Klebsiella pneumoniae serotypes from different sources and their sensitivity to cephalosporins.

153 strains of Klebsiella pneumoniae from 16 microbiological institutes in Germany, Austria and Switzerland were typed biochemically and serologically; their sensitivities to cefoxitin, cefotaxime, ceftazidime, ceftriaxone, lamoxactam, thienamycin and gentamicin were determined. The strains could be classified into seven biotypes and 43 K-antigen types. The distribution of the K-antigen types was random, and spread over the whole spectrum of the 72 possibilities. Regional variations were not observed. 4.6% of the isolates were resistant to cefoxitin and 23% were moderately sensitive. 98% of these Klebsiella strains were sensitive to the new cephalosporins which were also effective against gentamicin-resistant isolates accounting for 12% of all isolates studied. Cefoxitin was only slightly active against such strains. The effect of a standard concentration of each agent on bacterial cultures during their growth phase was measured in the Jouan biophotometer. The beta-lactamase-stable cephalosporins had a permanent bactericidal effect on the enzyme-producing reference strain, although the latent period varied considerably in some cases. Piperacillin and cefoperazone were not bactericidal in this test.