Rapid identification and genotyping of the honeybee pathogen Paenibacillus larvae by combining culturing and multiplex quantitative PCR

Background: American Foulbrood (AFB) is a devastating disease of honey bee (Apis mellifera) larvae caused by the spore-forming, Gram-positive bacterium Paenibacillus larvae. In most countries, the law requires mandatory reporting of AFB to the veterinary authority.

Aim and methods: To speed up detection and genotyping of P. larvae spores, we compared different culturing protocols on Columbia sheep blood agar and developed a new multiplex quantitative polymerase chain reaction to distinguish between the two relevant P. larvae genotypes enterobacterial repetitive intergenic consensus (ERIC) I and ERIC II.

Results and conclusion: As confirmed by P. larvae reference strains and field isolates, the new identification and genotyping protocol halves the time of current workflows, lessens labor-intension, allows a higher throughput of samples for monitoring, and permits a faster intervention to prevent the spread of AFB.