Characterization of Staphylococcus aureus isolates from oral surgical outpatients compared to isolates from hospitalized and non-hospitalized individuals.

In 160 patients, 114 strains of Staphylococcus aureus were isolated from gingival mucosa, saliva, throat and nose. The patients were divided into 4 groups: one group from an oral surgery clinic for outpatients, one group from a dental clinic, one group from a general surgery clinic for inpatients and one group from a clinic for chronically ill and aged patients. The highest frequency of staphylococcal carriers was found in the outpatient groups (oral surgery and dental clinic), 55% and 45%, respectively. Antibiotic sensitivity testing revealed the majority of the strains to be penicillin resistant, but sensitive to isoxazolyl-penicillins, clindamycin and lincomycin. 50% of the strains produced penicillinase. About 90% of all strains produced lipase, nuclease and a haemolysin most active on rabbit erythrocytes. Human and sheep erythrocytes were lysed by 70% and 46% of the strains, respectively. 77% of the strains were bacteriolytic active. No strain produced lecitinase or elastase. No significant difference was found between the 4 groups in the formation of any of these factors. Phage-type I and III dominated but there was no correlation to enzyme production or patient groups. Thus the 4 patient groups were colonized with strains of Staphylococcus aureus that showed mainly the same pathogenetic factors.