Isolation, characterization, and genetic diversity of Paenibacillus larvae from AFB suspected specimens in the Central and Eastern Black Sea Regions

American foulbrood is an important bacterial disease affecting the larvae of honey bees (Apis mellifera L.) caused by Paenibacillus larvae. Due to easy transmission of disease and the ability of bacteria to create spores, it is a bacterium resistant to both physical and chemical conditions. The study aims to isolate, perform microbiological analyses, and determine biochemical properties and genotypes P. larvae strains from AFB samples collected from Turkey's Central and Eastern Black Sea regions. An isolation study was conducted on adult bees, larvae, honey, and primary honeycomb samples from suspected colonies in the regions under study. After the purification of bacterial isolates from samples, P. larvae strains were identified using biochemical and molecular methods. The genetic diversity and ERIC types of P. larvae isolates were determined by rep-PCR DNA genotyping using BOX A1R and MBO REP1 primers and multiplex-PCR. A phylogenetic tree of P. larvae strains was constructed in the study. All P. larvae isolates were determined as ERIC I type. According to the rep-PCR results of P. larvae strains, 15 of the 28 isolates were Ab genotype (54%), 7 (25%) A beta genotype, 4 (14%) AB genotype, 1 (3.5%) alpha B genotype, and 1 (3.5%) ab genotype. From an epidemiological viewpoint, it was determined that Ab and A beta genotypes were widely distributed, while other genotypes (AB, alpha B, and ab) showed less spread. The results of the study will guide researchers in taking relevant measures to prevent and control American foulbrood.