Unique DNA fingerprint patterns of Paenibacillus larvae subsp larvae strains

Paenibacillus larvae subsp. larvae, the causative agent of American foulbrood, is an economically important pathogen in Argentina. Using the polymerase chain reaction (PCR) with primers that anneal to dispersed repetitive bacterial sequences, we generated genomic fingerprints of a collection of 100 P. I. larvae isolates. By using BOX-primers, the strains were grouped into three clusters named A, B and C, respectively. Genotypes A and C were closely related, and all three patterns were highly similar. P. I. larvae banding patterns were distinctive from those of all other Paenibacillus, Bacillus and Brevibacillus species from apiarian sources (n = 41) examined in this work. Paenibacillus larvae subsp, pulvifaciens, the causative agent of powdery scale disease, was closely related to P. I. larvae genotype B, where the only difference found between these subspecies was a band of about 2000 bp. When using ERIC-primers, band differences between both subspecies were not detectable whereas clear differences were noticed with REP-primers. The fingerprints obtained with BOX- and REP-primers appeared unique to P. I. larvae in relation to those generated by other Paenibacillus, Bacillus and Brevibacillus species that share the same habitat.