[Sensitivity of Staphylococcus aureus isolated clinically to CEPs. Results obtained with strains originating in superficial abscess in infants (author's transl)].

Seven CEPs agents (CEX, CXD, CDX, CEZ, CTM, CMZ and CXM) were examined for their MIC's against 240 strains of S. aureus isolated from superficial abscesses in infants. 1) Oral agents of CEPs, CEX, CXD and CDX gave similar results in MIC50, MIC80 and MIC90. Eight to 10% of the strains had high MIC's considered to be resistant at an inoculum size of 10(8) CFU/ml. 2) In injectable agents of CEPs, CEZ, CTM, CMZ and CXM, MIC50 showed MIC reflecting their antibacterial activity and MIC80 covered MIC which was considered as clinically effective. However, MIC90 reflected the presence of bacteria considered to be resistant to some degree and differed from one agent to another. The proportion of the strains which gave 50 micrograms/ml or higher MIC at an inoculum size of 10(8) CFU/ml was 5.8% for CEZ, 4.6% for CTM, and 7.1% for CXM, suggesting the presence of resistant bacteria at a proportion of 5-7%. In contrast, it was as low as 0.8% for CMZ. 3) These results indicate that strains resistant to CEPs tend to increase and take root in bacteria existing in quite usual and general living environment such as S. aureus isolated from superficial abscess in infants. This is a serious situation. Various studies on bacteria resistant to CEPs are being expected to be performed in each field.