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Penicillin-Resistant Anthrax Bacilli Isolated from a Dead Dairy Cow

1972; Canadian Veterinary Medical Association; Volume: 25; Issue: 4 Linguagem: Inglês

10.12935/jvma1951.25.184

2186-0211

Kaoru KOSHIMIZU, M Ogata, Kaori Shintani‐Ishida,

Bacterial Genetics and Biotechnology

Gram-positive bacilli were isolated from the venous blood of a dairy cow which died of suspected anthrax in Ryugasaki, Ibaraki Prefecture, in August, 1970. They were identified as Bacillus anthracis (Ryugasaki strain), since they had a capsule, gave a positive phage test, and were pathogenic for mice. As they gave a negative pearl test, they were subjected to the penicillin sensitivity test. The minimum inhibitory concentration (MIC) was 8, 000u/ml for the Ryugasaki strain, while it was 0.05-0.10u/ml for the control strain of B. anthracis.There were no great differences in sensitivity to other antibiotics than penicillin or sulfa drugs, or in biological properties between the Ryugasaki and control strains. Pathogenicity for mice, as examined by the method of ROTH et al., seemed to be a little lower in the isolated strain than in the control.The centrifugal supernatant of an overnight culture fluid of that strain in tryptosoy broth inactivated 2, 000u/ml of penicillin G completely. This result suggests the presence of penicillinase as the mechanism of resistance of this strain to penicillin.Attention should be paid to the occurrence of penicillin-resistant anthrax bacilli when the diagnosis and treatment of anthrax are to be performed.