Molecular epidemiology of the Bacillus anthracis isolates collected throughout Turkey from 1983 to 2011

Abstract

The main perspective of this study was to determine cross-transmissions amongst anthrax cases and provide detailed information regarding the genotypes of Bacillus anthracis isolates circulating in Turkey. A total of 251 B. anthracis isolates were obtained from human (93 isolates), animal (155 isolates), and environmental (three isolates) samples in various provinces of Turkey. All isolates were susceptible to quinolones, vancomycin, tigecycline, and linezolid, but not to ceftriaxone. Excluding human isolates, one of the animal isolates was found to be resistant to penicillin, erythromycin, and doxycycline. Multiple-locus variable-number tandem repeats analysis including 8 loci (MLVA8) revealed 12 genotypes, in which genotype 43 was observed at the highest frequency (41.8 %), followed by genotype 35 (25.5 %) and genotype 27 (10.4 %). Major subtype A3.a was the predominant cluster, including 86.8 % of the isolates. The MLVA25 analysis for the 251 isolates yielded 62 different genotypes, 33 of which had only one isolate, while the remaining 29 genotypes had 2 to 43 isolates, with a total of 218 isolates (86.9 %). These findings indicate very high cross-transmission rates within anthrax cases in Turkey. The genotypes diagnosed in Turkey are populated in the A major cluster. Penicillin prescribed as the first-choice antibiotic for the treatment of anthrax is still effective.