Phylogeographic distribution of Bacillus anthracis strains from humans and animals in Türkiye: Genotyping based on MLVA-31 loci analysis (2010–2021)

This molecular microbiological study aimed to investigate the genotype characterization of Bacillus anthracis (B. anthracis) strains circulating in Türkiye. A total of 114 B. anthracis strains [82 from animal isolates, 28 from human isolates, 3 Refik Saydam Culture Collection (RSKK) strains, and 1 Max Sterne vaccine strain] from 2010 to 2021 were included in the study. The Multiple-locus Variable Number Tandem Repeat Analysis (MLVA) was performed using MLVA 31-loci. A total of 70 genotypes were revealed, including 4 different clusters (A, C1, C2, and C3), and there was 1 genotype in cluster A, 8 genotypes in cluster C1, 40 genotypes in cluster C2, and 21 genotypes in cluster C3. The C2 cluster was determined to be the most dominant cluster (68.4%) among all strains. The G18 (Genotype 18 contained 20 strains from 13 provinces in 4 geographical regions) was revealed to be the most common among the genotypes in the C2 cluster. It was observed that the same genotype can be found from different origins, in different cities, and in different years. The investigation of the temporal and spatial distribution of B. anthracis genotypes throughout a country could determine the possible origin of the cases. Furthermore, it has been shown that the discriminatory power of the MLVA-31 method is higher than that of the previous MLVA-25 method. Identifying and monitoring the local, regional, and international genetic characterization of B. anthracis is essential in combating potential anthrax outbreaks, which can be a public health issue.