Bacillus anthracis but not always anthrax

• Published in: Journal of applied bacteriology Vol. 72; no. 1; pp. 21 - 28
• Main Authors: Turnbull, P.C.B, Hutson, R.A, Ward, M.J, Jones, M.N, Quinn, C.P, Finnie, N.J, Duggleby, C.J, Kramer, J.M, Melling, J
• Format: Journal Article
• Language: English
• Published: England 1992
• Subjects: Animals; anthrax; Anthrax - microbiology; Bacillus anthracis; Bacillus anthracis - genetics; Bacillus anthracis - isolation & purification; Bacillus anthracis - pathogenicity; bacterial antigens; DNA Probes; DNA, Bacterial - analysis; genotype; Humans; Nucleic Acid Hybridization; Phenotype; Plasmids; Polymerase Chain Reaction; strain differences; strains; Virulence
• ISSN: 0021-8847; 2056-5232
• DOI: 10.1111/j.1365-2672.1992.tb04876.x

Gram-positive bacilli isolated during epidemiological investigations which, on the basis of conventional tests, resemble Bacillus anthracis but which fail to produce the capsule or to induce anthrax in test animals have long been dismissed in clinical and veterinary laboratories as B. cereus or simply as unidentified Bacillus spp. and there upon discarded as inconsequential. In this study, the application of newly available DNA probe, polymerase chain reaction and specific toxin antigen detection technology has revealed that a proportion of such strains are B. anthracis which lack the plasmid carrying the capsule gene (pXO2). While these techniques cannot, of course, be used to confirm the identities of strains resembling B. anthracis but which also lack the plasmid carrying the toxin genes (pXO1), the likelihood that these also are bona fide B. anthracis becomes more acceptable. (As yet no naturally occurring pXO1-/2+ strains have been found.) At this point, the significance of the presence of such avirulent forms of B. anthracis in specimens can only be a subject for speculation, but the possibility that they may be indicators of virulent parents somewhere in the system being examined must be considered.