Polyphasic characterization of Bacillus species from anthrax outbreaks in animals from South Africa and Lesotho

  • Kgaugelo Edward Lekota The Biotechnology Platform, Agricultural Research Council, Onderstepoort, South Africa
  • Ayesha Hassim University of Pretoria, Onderstepoort, South Africa
  • Joseph Mafofo The Biotechnology Platform, Agricultural Research Council, Onderstepoort, South Africa
  • Jasper Rees The Biotechnology Platform, Agricultural Research Council, Onderstepoort, South Africa
  • Farai Catherine Muchadeyi The Biotechnology Platform, Agricultural Research Council, Onderstepoort, South Africa
  • Henriette van Heerden University of Pretoria, Onderstepoort, South Africa
  • Evelyn Madoroba Agricultural Research Council, Onderstepoort Veterinary Institute, Onderstepoort, South Africa
Keywords: Bacillus species, Bacillus anthracis, anthrax, bacteriology, molecular techniques

Abstract

Introduction: Bacillus anthracis is the causative agent of anthrax, a disease endemic in regions of Northern Cape Province and Kruger National Park of South Africa. Accurate identification of virulent B. anthracis is essential but challenging due to its close relationship with other members of B. cereus group. This study characterized B. anthracis and Bacillus species that were recovered from animals and the environment where animals died of anthrax symptoms in southern Africa using a polyphasic approach.

Methodology: For this purpose, 3 B. anthracis and 10 Bacillus isolates were subjected to microbiology tests, BiologOmniLog identification system (Biolog), 16S ribosomal RNA (rRNA) sequence analysis, polymerase chain reaction (PCR) detection of protective antigen (pag) and capsule (cap) regions, and real-time PCR using hybridization probes targeting chromosomal, pag, and capC genes.

Results: The Bacillus isolates were non-hemolytic, non-motile, and susceptible to penicillin, which is typical of B. anthracis, but resistant to gamma phage, unlike typical B. anthracis. The Biolog system and 16S rRNA gene sequence analysis identified most of the Bacillus isolates as B. endophyticus (7 of 10). Conventional PCR revealed that most of the Bacillus isolates contained capBCA gene regions. This highlights the limitation of the specificity of conventional PCR and the fact that the real-time PCR is more specific and reliable for anthrax diagnosis.

Conclusions: Real-time PCR, 16S rRNA sequencing, and confirmatory microbiology tests including phage resistance distinguished Bacillus isolates from B. anthracis in this study. Identification of B. anthracis should be done using a polyphasic approach.

Author Biographies

Kgaugelo Edward Lekota, The Biotechnology Platform, Agricultural Research Council, Onderstepoort, South Africa

and

Department of Veterinary Tropical Diseases, University of Pretoria, Onderstepoort,  South Africa

 

Bacteriology Section, Agricultural Research Council-Onderstepoort Veterinary Institute, 100 Old Soutpan Road, Onderstepoort 0110, South AfricaCollege of Agriculture and Environmental Sciences, University of South Africa, Florida, South Africa

 

Evelyn Madoroba, Agricultural Research Council, Onderstepoort Veterinary Institute, Onderstepoort, South Africa
Bacteriology Section, Agricultural Research Council-Onderstepoort Veterinary Institute, 100 Old Soutpan Road, Onderstepoort 0110, South AfricaCollege of Agriculture and Environmental Sciences, University of South Africa, Florida, South Africa
Published
2016-08-31
How to Cite
1.
Lekota KE, Hassim A, Mafofo J, Rees J, Muchadeyi FC, van Heerden H, Madoroba E (2016) Polyphasic characterization of Bacillus species from anthrax outbreaks in animals from South Africa and Lesotho. J Infect Dev Ctries 10:814-823. doi: 10.3855/jidc.7798
Section
Original Articles