Proposal to reclassify Paenibacillus larvae subsp. pulvifaciens DSM 3615 (ATCC 49843) as Paenibacillus larvae subsp. larvae. Results of a comparative biochemical and genetic study

2006

Apidologie

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-American foulbrood, a worldwide bacterial disease of honeybee brood caused by the grampositive bacterium Paenibacillus larvae, is one of the most serious bee diseases. This review will focus on recent achievements in the study of Paenibacillus larvae brought about by molecular methods introduced into the field over the last fifteen years. One topic will be the classification of the etiological agent, which has changed several times since the first description in 1906 and was most recently modified again. Different genetic and biochemical methods for subtyping Paenibacillus larvae, the analysis of differences in virulence and the implications of these differences will also be covered.American foulbrood / Paenibacillus larvae / taxonomy / genotyping / virulence Abbreviations: AFB (American Foulbrood), P. l. larvae (Paenibacillus larvae subsp. larvae), P. l. pulvifaciens (Paenibacillus larvae subsp. pulvifaciens), P. larvae (Paenibacillus larvae), CFU (colony forming units), LC 50 (lethal concentration killing 50% of the larvae).

Section: Reclassification Of the Etiological Agentmentioning

confidence: 99%

Section: Reclassification Of the Etiological Agentmentioning

confidence: 99%

Reclassification, genotypes and virulence ofPaenibacillus larvae, the etiological agent of American foulbrood in honeybees – a review

Ashiralieva

2006

Apidologie

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“…The convoluted surface of P. larvae larvae isolates belonging to the pigmented variant has not been described previously. Although P. larvae pulvifaciens has been described as having ridges running longitudinally along the rod-shaped spores, in contrast to the smooth surface of P. larvae larvae spores (Ludvik et al, 1993), this difference can no longer be used to distinguish between the two P. larvae subspecies since one of the type strains for P. larvae pulvifaciens (DSM 3615 T ) containing such ridges has unambiguously been characterized as P. larvae larvae (Kilwinski et al, 2004).…”

Section: Phenotypic Characterizationmentioning

confidence: 99%

“…As this isolate has been demonstrated to be indistinguishable from reference strains of P. larvae larvae (Kilwinski et al, 2004), the validity of these studies can be questioned.…”

Section: Introductionmentioning

confidence: 99%

Reclassification of Paenibacillus larvae subsp. pulvifaciens and Paenibacillus larvae subsp. larvae as Paenibacillus larvae without subspecies differentiation

International Journal of Systematic and Evolutionary Microbiology

Forsgren

Pentikäinen³

et al. 2006

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300

386

A polyphasic taxonomic study of the two subspecies of Paenibacillus larvae, Paenibacillus larvae subsp. larvae and Paenibacillus larvae subsp. pulvifaciens, supported the reclassification of the subspecies into one species, Paenibacillus larvae, without subspecies separation. Our conclusions are based on the analysis of six reference strains of P. larvae subsp. pulvifaciens and three reference strains and 44 field isolates of P. larvae. subsp. larvae. The latter originated from brood or honey of clinically diseased honey bee colonies or from honey of both clinically diseased and asymptomatic colonies from Sweden, Finland and Germany. Colony and spore morphology, as well as the metabolism of mannitol and salicin, did not allow a clear identification of the two subspecies and SDS-PAGE of whole-cell proteins did not support the subspecies differentiation. For genomic fingerprinting, repetitive element-PCR fingerprinting using ERIC primers and PFGE of bacterial DNA were performed. The latter method is a high-resolution DNA fingerprinting method proven to be superior to most other methods for biochemical and molecular typing and has not previously been used to characterize P. larvae. ERIC-PCR identified four different genotypes, while PFGE revealed two main clusters. One cluster included most of the P. larvae subsp. larvae field isolates, as well as all P. larvae subsp. pulvifaciens reference strains. The other cluster comprised the pigmented variants of P. larvae subsp. larvae. 16S rRNA gene sequences were determined for some strains. Finally, exposure bioassays demonstrated that reference strains of P. larvae subsp. pulvifaciens were pathogenic for honey bee larvae, producing symptoms similar to reference strains of P. larvae subsp. larvae. In comparison with the type strain for P. larvae subsp. larvae, ATCC 9545 T , the P. larvae subsp. pulvifaciens strains tested were even more virulent, since they showed a shorter LT 100 . An emended description of the species is given.

“…Cultivation and identification of the isolates were performed as described previously (7,12). Detailed biochemical and genetic analyses of the reference strain and the field strains 00-087, 01-455, 02-130, 03-125, 01-440, 02-113, 02-120, 03-159, 00-1163, 03-522, and 03-525 have been already reported (10,12). For genetic fingerprinting of the five additional isolates used in this study, previously described techniques were employed (7,12).…”

mentioning

confidence: 99%

Strain- and Genotype-Specific Differences in Virulence of Paenibacillus larvae subsp. larvae , a Bacterial Pathogen Causing American Foulbrood Disease in Honeybees

Ashiralieva

Fries

2005

Appl Environ Microbiol

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170

252

Virulence variations of Paenibacillus larvae subsp. larvae, the causative agent of American foulbrood disease of honeybees, were investigated by analysis of 16 field isolates of this pathogen, belonging to three previously characterized genotypes, as well as the type strain (ATCC 9545) of P. larvae subsp. larvae, with exposure bioassays. We demonstrated that the strain-specific 50% lethal concentrations varied within an order of magnitude and that differences in amount of time for the pathogen to kill 100% of the infected hosts (LT 100 ) correlated with genotype. One genotype killed rather quickly, with a mean LT 100 of 7.8 ؎ 1.7 days postinfection, while the other genotypes acted more slowly, with mean LT 100 s of 11.2 ؎ 0.8 and 11.6 ؎ 0.6 days postinfection.