Further studies on staphylococci in meats. IV. The bacteriophage pattern and antibiotic sensitivity of isolates from nonfrozen meats.

Of 272 isolates of Staphylococcus aureus recovered from 173 samples of 10 market meats from 27 stores, 173 (63.2%) were phage typable, employing 28 phages. Sixty per cent of the phage-typable strains belonged to group III, followed by 14.5% to mixed groups I and III, 10.4% to Group I, 8.7% to all mixed groups, 4.6% to group II, and 1.7% to group IV. The most commonly recovered patterns were 83, 53/83, and other similar combinations of 53. The nonpigmented strains which did not have bound coagulase were less phage sensitive than the pigmented strains having bound coagulase. None of the isolates were resistant to novobiocin, kanamycin, chloramphenicol, and erythromycin. Twenty-three per cent were resistant to streptomycin, 17% to ristocetin, 11% to penicillin, and 4.4% to chlortetracycline. The phage types are compared to those of other food and human isolates and found not to differ too greatly. Their possible origins into the meats are discussed.