Absence of Lethal Effect of Penicillin in Germ-free Guinea Pigs.

473:b:1,5) proved the 0 antigen of S. chersina to be complex and composed of 47, and 473. Therefore, S. chersina shares the same 0 complex with S. kaolack, S. phoenix, and S. lyon, i.e., with the majority of the 0-47 members. [See Kauffmann (Acta Pathol. Microbiol. Scand. 56:343351, 1962) for further information about the 0 group 47.] When S. chersina was placed in tubes of semisolid medium which contained z serum for the isolation of phase 2, migration through the medium was noted after 24 to 48 hr of incubation. The spreading growth was agglutinated by the H antiserum Z6. Antigen relations exist between the z6 fraction of S. chersina and the Ha antigen. S. chersina has the formula 471, 473:z:z6. S. chersina was primarily resistant to: ampicillin (25,g), cloxacillin (5,ug), oxacillin (5,ug), methicillin (10 gg), phenethicillin (5 ,g), tetracycline phosphate (50 ,g), novobiocin (30 ,ug), erythromycin (6 ,ug), matromycin (15 Mg), and spiramycin (30 Mg). It was sensitive to streptomycin (50 ,g), chloramphenicol (20 ,ig), neomycin (50 ,ug), framycetin (100 ,ug), and kanamycin (30 ,ug). The antibiogram was carried out on paper discs with the amounts stated. The 0-1 phage disintegrates only about 30% S. chersina colonies. Therefore, S. chersina is only partially sensitive to the 0-1 phage. Similar to S. calvinia (Brede, Zentr. Bakteriol. Parasitenk. Abt. I Orig. 188:137, 1963), the 0-1 phage resistance of S. chersina is even stronger than in the case of S. zanzibar, until the present the usual control species for 0-1 phage tests. These facts were confirmed by H. Fry, Bern, Switzerland, to whom I express my thanks for doing control tests.