title: [Actual resistance of Staphylococcus aureus: beta-Lactamase production and susceptibility to various penicillins and erythromycin (author's transl)].
abstract: The actual resistance of Staphylococcus aureus from different clinics in Bielefeld was examined on the basis of 155 strains freshly isolated from clinical specimens during a period of two months. Sensitivity of these strains was assessed by minimum inhibitory concentrations (MICs) as determined by agar dilution method. As expected oxacillin proved to be the most effective compound according to its stability to beta-lactamases. Ampicillin and amoxicillin were nearly as active as penicillin G, while propicillin exhibited a higher activity than penicillin G against those strains which were moderately sensitive to penicillin G. Mics of erythromycin were similar to those of propicillin and most of the highly penicillin resistant strains proved to be resistant to erythromycin too. When comparing the acylureidopenicillins and ticarcillin nearly identical MIC values resulted for azlocillin, mezlocillin and piperacillin; ticarcillin was found to be slightly less active. The qualitative assay for beta-lactamase activity performed after induction with methicillin demonstrated strong correlation between presence or absence of beta-lactamases and sensitivity of the bacteria to penicillin G. beta-lactamase activity could be found in almost all strains with MIC greater than or equal to 0.25 micrograms/ml for penicillin G. These results are discussed with respect to the recommendations for susceptibility testing.
mesh_terms: D004917:Erythromycin / Q000494:pharmacology*; D010403:Penicillin Resistance; D010405:Penicillinase / Q000096:biosynthesis; D010406:Penicillins / Q000494:pharmacology*; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000201:enzymology; D001618:beta-Lactamases / Q000502:physiology*
chemical_list: D010406:Penicillins; D004917:Erythromycin; D010405:Penicillinase; D001618:beta-Lactamases
vernacular_title: Zur Resistenzlage von Staphylococcus aureus: beta-Laktamasebildung und Empfindlichkeit genenüber verschiedenen Penicillinen sowie Erythromycin.