title: The expression of capsule in serum-soft agar by Staphylococcus aureus isolated from human clinical sources.
abstract: Staphylococcus aureus isolates from human clinical sources were incubated for various times in modified 110 medium and tested for production of capsule by the serum-soft agar technique. Ten (5.7%) of 175 isolates were encapsulated after incubation for 24 h. A more detailed examination of 77 isolates showed that incubation period affected the production of capsule. After 2 h, 31% were encapsulated, but after 6 h and 24 h this decreased to 17% and 4% respectively. Rapid passage in vitro induced the expression of capsule in four of 50 unencapsulated strains. Only three of 20 encapsulated strains could be typed with standard antisera.
mesh_terms: D000362:Agar; D003470:Culture Media; D006801:Humans; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis*; D012703:Serotyping; D013203:Staphylococcal Infections / Q000382:microbiology; D013211:Staphylococcus aureus / Q000145:classification / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*
chemical_list: D003470:Culture Media; D011135:Polysaccharides, Bacterial; D000362:Agar