Transcriptional Response of Honey Bee Larvae Infected with the Bacterial Pathogen Paenibacillus larvae

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 9545T, the P. larvae subsp. pulvifaciens strains tested were even more virulent, since they showed a shorter LT100. An emended description of the species is given.

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Biochemical characterization of different genotypes of Paenibacillus larvae subsp. larvae, a honey bee bacterial pathogen

Microbiology ◽

10.1099/mic.0.27125-0 ◽

2004 ◽

Vol 150 (7) ◽

pp. 2381-2390 ◽

Cited By ~ 59

Author(s):

Sandra Neuendorf ◽

Kati Hedtke ◽

Gerhard Tangen ◽

Elke Genersch

Keyword(s):

Honey Bee ◽

Reference Strain ◽

Biochemical Characterization ◽

Bacterial Pathogen ◽

Paenibacillus Larvae ◽

Bacterial Disease ◽

System A ◽

Biolog System ◽

Far Future

Paenibacillus larvae subsp. larvae (P. l. larvae) is the aetiological agent of American foulbrood (AFB), the most virulent bacterial disease of honey bee brood worldwide. In many countries AFB is a notifiable disease since it is highly contagious, in most cases incurable and able to kill affected colonies. Genotyping of field isolates of P. l. larvae revealed at least four genotypes (AB, Ab, ab and α B) present in Germany which are genotypically different from the reference strain DSM 7030. Therefore, based on these data, five different genotypes of P. l. larvae are now identified with genotype AB standing out with a characteristic brown-orange and circled two-coloured colony morphology. Analysing the metabolic profiles of three German genotypes (AB, Ab and ab) as well as of the reference strain using the Biolog system, a characteristic biochemical fingerprint could be obtained for each strain. Cluster analysis showed that while genotypes Ab, ab and the reference strain DSM 7030 are rather similar, genotype AB is clearly different from the others. Analysis of all isolates for plasmid DNA revealed two different plasmids present only in isolates belonging to genotype AB. Therefore, genotype AB is remarkable in all aspects analysed so far. Future analysis will show whether or not these differences will expand to differences in virulence.

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Complete Genome Sequence of Paenibacillus larvae MEX14, Isolated from Honey Bee Larvae from the Xochimilco Quarter in Mexico City

Genome Announcements ◽

10.1128/genomea.00968-15 ◽

2015 ◽

Vol 3 (4) ◽

Cited By ~ 1

Author(s):

D. Peréz de la Rosa ◽

J. J. Pérez de la Rosa ◽

R. Cossio-Bayugar ◽

E. Miranda-Miranda ◽

L. Lozano ◽

...

Keyword(s):

Mexico City ◽

Honey Bee ◽

Genome Sequence ◽

Complete Genome Sequence ◽

Complete Genome ◽

Paenibacillus Larvae ◽

Honey Bee Larvae

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Novel probiotic approach to counter Paenibacillus larvae infection in honey bees

The ISME Journal ◽

10.1038/s41396-019-0541-6 ◽

2019 ◽

Vol 14 (2) ◽

pp. 476-491 ◽

Cited By ~ 14

Author(s):

Brendan A. Daisley ◽

Andrew P. Pitek ◽

John A. Chmiel ◽

Kait F. Al ◽

Anna M. Chernyshova ◽

...

Keyword(s):

Honey Bee ◽

Honey Bees ◽

Lactobacillus Rhamnosus ◽

Paenibacillus Larvae ◽

Causative Organism ◽

Immune Genes ◽

Pathogen Load ◽

Probiotic Lactobacilli ◽

Honey Bee Larvae

Abstract American foulbrood (AFB) is a highly virulent disease afflicting honey bees (Apis mellifera). The causative organism, Paenibacillus larvae, attacks honey bee brood and renders entire hives dysfunctional during active disease states, but more commonly resides in hives asymptomatically as inactive spores that elude even vigilant beekeepers. The mechanism of this pathogenic transition is not fully understood, and no cure exists for AFB. Here, we evaluated how hive supplementation with probiotic lactobacilli (delivered through a nutrient patty; BioPatty) affected colony resistance towards a naturally occurring AFB outbreak. Results demonstrated a significantly lower pathogen load and proteolytic activity of honey bee larvae from BioPatty-treated hives. Interestingly, a distinctive shift in the microbiota composition of adult nurse bees occurred irrespective of treatment group during the monitoring period, but only vehicle-supplemented nurse bees exhibited higher P. larvae loads. In vitro experiments utilizing laboratory-reared honey bee larvae showed Lactobacillus plantarum Lp39, Lactobacillus rhamnosus GR-1, and Lactobacillus kunkeei BR-1 (contained in the BioPatty) could reduce pathogen load, upregulate expression of key immune genes, and improve survival during P. larvae infection. These findings suggest the usage of a lactobacilli-containing hive supplement, which is practical and affordable for beekeepers, may be effective for reducing enzootic pathogen-related hive losses.

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Diverse origins of tetracycline resistance in the honey bee bacterial pathogen Paenibacillus larvae

Journal of Invertebrate Pathology ◽

10.1016/s0022-2011(03)00039-9 ◽

2003 ◽

Vol 83 (1) ◽

pp. 46-50 ◽

Cited By ~ 89

Author(s):

Jay D Evans

Keyword(s):

Honey Bee ◽

Bacterial Pathogen ◽

Tetracycline Resistance ◽

Paenibacillus Larvae

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Effect of Bodily Fluids from Honey Bee (Apis mellifera) Larvae on Growth and Genome-Wide Transcriptional Response of the Causal Agent of American Foulbrood Disease (Paenibacillus larvae)

PLoS ONE ◽

10.1371/journal.pone.0089175 ◽

2014 ◽

Vol 9 (2) ◽

pp. e89175 ◽

Cited By ~ 1

Author(s):

Lina De Smet ◽

Dieter De Koker ◽

Alyse K. Hawley ◽

Leonard J. Foster ◽

Paul De Vos ◽

...

Keyword(s):

Apis Mellifera ◽

Honey Bee ◽

Transcriptional Response ◽

Causal Agent ◽

Paenibacillus Larvae ◽

American Foulbrood ◽

Bodily Fluids ◽

Genome Wide ◽

American Foulbrood Disease

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Anti-Virulence Strategy against the Honey Bee Pathogenic Bacterium Paenibacillus larvae via Small Molecule Inhibitors of the Bacterial Toxin Plx2A

Toxins ◽

10.3390/toxins13090607 ◽

2021 ◽

Vol 13 (9) ◽

pp. 607

Author(s):

Julia Ebeling ◽

Franziska Pieper ◽

Josefine Göbel ◽

Henriette Knispel ◽

Michael McCarthy ◽

...

Keyword(s):

Small Molecules ◽

Honey Bee ◽

Small Molecule ◽

Bacterial Infections ◽

Small Molecule Inhibitors ◽

Paenibacillus Larvae ◽

Bacterial Toxin ◽

American Foulbrood ◽

Honey Bee Larvae

American Foulbrood, caused by Paenibacillus larvae, is the most devastating bacterial honey bee brood disease. Finding a treatment against American Foulbrood would be a huge breakthrough in the battle against the disease. Recently, small molecule inhibitors against virulence factors have been suggested as candidates for the development of anti-virulence strategies against bacterial infections. We therefore screened an in-house library of synthetic small molecules and a library of flavonoid natural products, identifying the synthetic compound M3 and two natural, plant-derived small molecules, Acacetin and Baicalein, as putative inhibitors of the recently identified P. larvae toxin Plx2A. All three inhibitors were potent in in vitro enzyme activity assays and two compounds were shown to protect insect cells against Plx2A intoxication. However, when tested in exposure bioassays with honey bee larvae, no effect on mortality could be observed for the synthetic or the plant-derived inhibitors, thus suggesting that the pathogenesis strategies of P. larvae are likely to be too complex to be disarmed in an anti-virulence strategy aimed at a single virulence factor. Our study also underscores the importance of not only testing substances in in vitro or cell culture assays, but also testing the compounds in P. larvae-infected honey bee larvae.

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Inhibitory effect of indole analogs against Paenibacillus larvae, the causal agent of American foulbrood disease

Journal of Insect Science ◽

10.1093/jisesa/iex080 ◽

2017 ◽

Vol 17 (5) ◽

Cited By ~ 5

Author(s):

Israel Alvarado ◽

Joseph W Margotta ◽

Mai M Aoki ◽

Fernando Flores ◽

Fresia Agudelo ◽

...

Keyword(s):

Honey Bee ◽

Spore Germination ◽

Inhibitory Effect ◽

Antagonistic Effect ◽

Paenibacillus Larvae ◽

American Foulbrood ◽

Bacterial Proliferation ◽

American Foulbrood Disease ◽

Honey Bee Larvae

Abstract Paenibacillus larvae, a Gram-positive bacterium, causes American foulbrood (AFB) in honey bee larvae (Apis mellifera Linnaeus [Hymenoptera: Apidae]). P. larvae spores exit dormancy in the gut of bee larvae, the germinated cells proliferate, and ultimately bacteremia kills the host. Hence, spore germination is a required step for establishing AFB disease. We previously found that P. larvae spores germinate in response to l-tyrosine plus uric acid in vitro. Additionally, we determined that indole and phenol blocked spore germination. In this work, we evaluated the antagonistic effect of 35 indole and phenol analogs and identified strong inhibitors of P. larvae spore germination in vitro. We further tested the most promising candidate, 5-chloroindole, and found that it significantly reduced bacterial proliferation. Finally, feeding artificial worker jelly containing anti-germination compounds to AFB-exposed larvae significantly decreased AFB infection in laboratory-reared honey bee larvae. Together, these results suggest that inhibitors of P. larvae spore germination could provide another method to control AFB.

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