779 OXACILLIN TOLERANT STAPHYLOCOCCAL BACTEREMIA IN CHILDREN

Some staphylococcus aureus strains are deficient in autolytic enzyme activity, resist killing with oxacillin and are called “oxacillin tolerant”. These strains grown in culture with oxacillin, are inhibited, but are not killed. Since the clinical significance of this laboratory observation is not clear we have tested all staphylococcal isolates from 38 children for oxacillir tolerance and reviewed their hospital records. Their ages ranged from newborns to 19 years of age. Eighteen were females and 20 were males. Sixteen of the 38 patients had “oxacillin tolerant” staphylococcal infections. Eight were newborns, 4 had cancer, and 4 had no underlying disease. Six of the 16 died, 3 of the 4 were cancer patients and 3 of 8 were newborns. Twenty-two of 38 strains were non-tolerant. Six of these patients were newborns, 5 had cancer and 11 had no underlying disease. Six of these 22 patients died, one of the cancer patients, 3 of the 6 newborns and 2 with no underlying disease. Children with oxacillin tolerant organisms have a higher case fatality rate than children with non-tolerant organisms;the difference is more striking in children with cancer, indicating that children with severely impaired host defenses are at greater risk. The deficient autolytic enzyme in these strains may interfere with effective phagocytosis and antibiotic action. The usual antibiotic therapy with penicillinase resistant penicillins may not be adequate.