title: Staphylococci, in vitro and in vivo.
abstract: Strains of Staphylococcus aureus were grown in broth and by the membrane technique; both drug-free media and media containing cloxacillin were used. The staphylococci grown in broth containing cloxacillin showed one thick cross wall and were larger than those grown in drug-free broth: 1.6 micron in diameter as opposed to 0.9 micron. The staphylococci grown on membranes placed on agar containing cloxacillin were 2-3 microns in diameter and contained three or more cross walls. Mice were infected intraperitoneally with staphylococci. After treatment with cloxacillin, the peritoneal fluid and spleens contained staphylococci that were 2-3 microns in diameter with three or more cross walls. A staphylococcal endocarditis was induced in rabbits that were then treated with cloxacillin. The staphylococci in the vegetation of the treated rabbits were 2-3 microns in diameter and contained multiple cross walls. Large staphylococci with multiple cross walls were observed in specimens from patients with respiratory infections treated with beta-lactam antibiotics. It appears, therefore, that the ultrastructure of staphylococci in vivo is comparable to that of staphylococci grown on a solid support medium such as a membrane, and different from that of staphylococci grown in a liquid medium.
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001853:Bone Marrow / Q000382:microbiology; D002473:Cell Wall / Q000648:ultrastructure; D003023:Cloxacillin / Q000494:pharmacology*; D003470:Culture Media; D004697:Endocarditis, Bacterial / Q000382:microbiology; D008567:Membranes, Artificial; D051379:Mice; D008854:Microscopy, Electron; D010019:Osteomyelitis / Q000382:microbiology; D011817:Rabbits; D051381:Rats; D013154:Spleen / Q000382:microbiology; D013183:Sputum / Q000382:microbiology; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development* / Q000472:pathogenicity / Q000648:ultrastructure
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media; D008567:Membranes, Artificial; D003023:Cloxacillin