Abstract
During an anthrax outbreak at the Pollino National Park (Basilicata, Italy) in 2004, diseased cattle were buried and from these anthrax-foci Bacillus anthracis endospores still diffuse to the surface resulting in local accumulations. Recent data suggest that B. anthracis multiplies in soil outside the animal-host body. This notion is supported by the frequent isolation of B. anthracis from soil lacking one or both virulence plasmids. Such strains represent an evolutionary dead end, as they are likely no longer able to successfully infect new hosts. This loss of virulence plasmids is explained most simply by postulating a soil-borne life cycle of the pathogen. To test this hypothesis we investigated possible microevolution at two natural anthrax foci from the 2004 outbreak. If valid, then genotypes of strains isolated from near the surface at these foci should be on a different evolutionary trajectory from those below residing in deeper-laying horizons close to the carcass. Thus, the genetic diversity of B. anthracis isolates was compared conducting Progressive Hierarchical Resolving Assays using Nucleic Acids (PHRANA) and next generation Whole Genome Sequencing (WGS). PHRANA was not discriminatory enough to resolve the fine genetic relationships between the isolates. Conversely, WGS of nine isolates from near-surface and nine from near-carcass revealed five isolate specific SNPs, four of which were found only in different near-surface isolates. In support of our hypothesis, one surface-isolate lacked plasmid pXO1 and also harbored one of the unique SNPs. Taken together, our results suggest a limited soil-borne life cycle of B. anthracis.
Highlights
Anthrax is a non-contagious infectious disease that principally afflicts domestic and wild ruminants but other animals including horses, donkeys, pigs, as well as humans are susceptible to infection
Additional experiments with bacteriophages showed that lysogeny of B. anthracis may enable the bacterium to colonize the intestinal tract of earthworms [30]. These findings suggest that B. anthracis is principally competent to grow in suitable soil environments, but this has not been directly observed in the environment far
Initial classification and canonical SNP (canSNP)-typing of B. anthracis isolates from Pollino National Park assign strains to canSNP group A
Summary
Anthrax is a non-contagious infectious disease that principally afflicts domestic and wild ruminants but other animals including horses, donkeys, pigs, as well as humans are susceptible to infection. While there is a general decrease in the number of anthrax outbreaks worldwide, anthrax is considered an extensively under-diagnosed and under-reported disease [5]. The etiological agent of anthrax, is a member of the Bacillus cereus sensu lato group [6] which comprises endospore-forming soil bacteria. Endospores are able to survive in extreme and unfavorable environmental conditions and remain viable in the soil over a long period of time. Due to the virulence of B. anthracis and because endospores are very stable in the environment and easy to cultivate, the bacterium is considered one of the most notorious agents to be potentially misused as a biological weapon or tool of bioterrorism [7,8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
