Identity and distribution of American foulbrood (Paenibacillus larvae) in South Africa

Abstract

American foulbrood (AFB) is a serious and near-global disease of honey bees and was recently discovered in South Africa. The causative pathogen, Paenibacillus larvae, comprises various strains. It is currently unknown which of these are present in South Africa and what their distribution is. We address this issue by genotyping P. larvae isolates using repetitive element fingerprinting (rep-PCR) markers and microfabricated chip technology. A total of 71 brood, honey and wax samples were collected opportunistically in South Africa. Twenty-three samples tested positive for P. larvae (32.4%). Diagnostic rep-PCR fingerprinting using ERIC, BOX A1R and MBO REP1 primers found all P. larvae isolates in South Africa to correspond to the ERIC I genotype, with two subtypes revealed, Ab (13 samples) and ab (10 samples). These results are in agreement with the global prevalence of the ERIC I AFB genotype among P. larvae-infected honey bee colonies.