Tetracycline-resistance encoding plasmids from Paenibacillus larvae, the causal agent of American foulbrood disease, isolated from commercial honeys

Paenibacillus larvae, the causal agent of American foulbrood disease in honeybees, acquires tetracycline-resistance via native plasmids carrying known tetracycline-resistance determinants. From three P. larvae tetracycline-resistant strains isolated from honeys, 5-kb-circular plasmids with almost identical sequences, designated pPL373 in strain PL373, pPL374 in strain PL374, and pPL395 in strain PL395, were isolated. These plasmids were highly similar (99%) to small tetracycline-encoding plasmids (pMA67, pBHS24, pBSDMV46A, pDMV2, pSU1, pAST4, and pLS55) that replicate by the rolling circle mechanism. Nucleotide sequences comparisons showed that pPL373, pPL374, and pPL395 mainly differed from the previously reported P. larvae plasmid pMA67 in the oriT region and mob genes. These differences suggest alternative mobilization and/or conjugation capacities. Plasmids pPL373, pPL374, and pPL395 were individually transferred by electroporation and stably maintained in tetracycline-susceptible P. larvae NRRL B-14154, in which they autonomously replicated. The presence of nearly identical plasmids in five different genera of gram-positive bacteria, i.e., Bhargavaea, Bacillus, Lactobacillus, Paenibacillus, and Sporosarcina, inhabiting diverse ecological niches provides further evidence of the genetic transfer of tetracycline resistance among environmental bacteria from soils, food, and marine habitats and from pathogenic bacteria such as P. larvae. [Int Microbiol 2014; 17(1):49-61]Keywords: American foulbrood disease (AFB) · Paenibacillus larvae · tetracycline resistance · plasmids · honeybee

Special issue on pests and pathogens in Apiculture: Navigating Old Challenges and Unveiling New Threats

In the realm of apiculture, the delicate balance between colonies, bees and the challenges posed by pests and pathogens has been a longstanding concern for researchers and beekeepers alike. The decision to dedicate a special edition to pests and pathogens in apiculture arose from the fact that a myriad of pests and pathogens are some of the main threats to bees across the world. Moreover, the increase in submissions during the recent period indicates a heightened research interest and an urgent imperative to confront the challenges associated with pests and pathogens in apiculture.info:eu-repo/semantics/publishedVersio

Microbiología apícola: valorización del polen en la industria alimentaria

Este artículo brinda la información generada por un trabajo de investigación desarrollado en el Laboratorio de Estudios Apícolas (www.labea.criba. edu.ar), cuyo objetivo fue contribuir a la valorización del polen apícola para la industria alimentaria

Diagnosis of American foulbrood in honey bees: A synthesis and proposed analytical protocols

Worldwide, American foulbrood (AFB) is the most devastating bacterial disease of the honey bee (Apis mellifera). Because the distinction between AFB and powdery scale disease is no longer considered valid, the pathogenic agent has recently been reclassified as one species Paenibacillus larvae, eliminating the subspecies designations Paenibacillus larvae subsp. larvae and Paenibacillus larvae subsp. pulvifaciens. The creamy or dark brown, glue-like larval remains of infected larvae continue to provide the most obvious clinical symptom of AFB, although it is not conclusive. Several sensitive and selective culture media are available for isolation of this spore-forming bacterium, with the type of samples that may be utilized for detection of the organism being further expanded. PCR methods for identification and genotyping of the pathogen have now been extensively developed. Nevertheless, biochemical profiling, bacteriophage sensitivity, immunotechniques and microscopy of suspect bacterial strains are entirely adequate for routine identification purposes.Facultad de Ciencias Agrarias y ForestalesCentro de Investigaciones de Fitopatologí

Diagnosis of American foulbrood in honey bees: A synthesis and proposed analytical protocols

Worldwide, American foulbrood (AFB) is the most devastating bacterial disease of the honey bee (Apis mellifera). Because the distinction between AFB and powdery scale disease is no longer considered valid, the pathogenic agent has recently been reclassified as one species Paenibacillus larvae, eliminating the subspecies designations Paenibacillus larvae subsp. larvae and Paenibacillus larvae subsp. pulvifaciens. The creamy or dark brown, glue-like larval remains of infected larvae continue to provide the most obvious clinical symptom of AFB, although it is not conclusive. Several sensitive and selective culture media are available for isolation of this spore-forming bacterium, with the type of samples that may be utilized for detection of the organism being further expanded. PCR methods for identification and genotyping of the pathogen have now been extensively developed. Nevertheless, biochemical profiling, bacteriophage sensitivity, immunotechniques and microscopy of suspect bacterial strains are entirely adequate for routine identification purposes.Facultad de Ciencias Agrarias y ForestalesCentro de Investigaciones de Fitopatologí

The Journal of Apicultural Research welcomes the publication of research findings from around the globe

The Journal of Apicultural Research (JAR) is a peer-reviewed, scientific journal dedicated to examining and publishing the latest research on bees from around the world. JAR publishes many different types of articles to reach different international audiences, from career scientists to students and well-informed beekeepers. These comprise original, theoretical, and experimental research papers, as well as authoritative notes, comments, and reviews on scientific aspects of all types of bees (superfamily Apoidea). As of 2021, JAR has an Impact Factor of 2.407 and is ranked 33rd out of 100 in the Entomology category (© InCites Journal Citation Reports®, Clarivate Analytics, 2022). Five regular issues are published per year and special issues are added when timely topics arise, the latest being a special issue on stingless bees (2022) and review papers (2023). In the last decade, COLOSS BEEBOOK chapters are published in JAR. These open-access chapters are a collection of the Standard Methods used in honey bee research, including the study of parasites, pests, and hive products. They are a primary reference resource for bee researchers across the globe and facilitate new projects that might not otherwise be undertaken by laboratories that are new to apidology (236,516 downloads - Taylor & Francis 3,028 citations - Web of Science, 2022). The Journal of Apicultural Research was founded by the International Bee Research Association (IBRA) in 1962. The very first issue included a Note from the first Editors, Dr. Eva Crane & Dr. James Simpson, who introduced JAR as a new opportunity for publication: “The journal will cover all aspects of bees, Apis and non-Apis, and substances used or produced by them, their pollinating activities, and organisms causing diseases or injuries to them.” Since the first issue, this legacy has been maintained in more than 2,800 scientific articles, co-authored by some 1,900 researchers, published so far in JAR, making our journal a key forum for the international exchange of scientific data in apidology. We encourage colleagues from around the globe to continue to participate in sharing their research with the scientific community by publishing in JAR.info:eu-repo/semantics/publishedVersio

Diagnosis of American foulbrood in honey bees: A synthesis and proposed analytical protocols

Worldwide, American foulbrood (AFB) is the most devastating bacterial disease of the honey bee (Apis mellifera). Because the distinction between AFB and powdery scale disease is no longer considered valid, the pathogenic agent has recently been reclassified as one species Paenibacillus larvae, eliminating the subspecies designations Paenibacillus larvae subsp. larvae and Paenibacillus larvae subsp. pulvifaciens. The creamy or dark brown, glue-like larval remains of infected larvae continue to provide the most obvious clinical symptom of AFB, although it is not conclusive. Several sensitive and selective culture media are available for isolation of this spore-forming bacterium, with the type of samples that may be utilized for detection of the organism being further expanded. PCR methods for identification and genotyping of the pathogen have now been extensively developed. Nevertheless, biochemical profiling, bacteriophage sensitivity, immunotechniques and microscopy of suspect bacterial strains are entirely adequate for routine identification purposes.Facultad de Ciencias Agrarias y ForestalesCentro de Investigaciones de Fitopatologí

Partial characterization of bacteriocin-like compounds from two strains of Bacillus cereus with biological activity against Paenibacillus larvae, the causal agent of American Foulbrood disease

American Foulbrood (AFB), caused by the spore-forming Gram-positive bacteriumPaenibacillus larvae,is the most severe bacterial disease affecting honeybees worldwide. Two bacterial isolates showing specific inhibitory activity againstP.larvaewere identified asBacillus cereusby 16S rDNA sequencing. Antagonistic compounds were obtained from cell-free supernatants of strains m6c and m387 growing on Trypticase Soy Broth and concentrated by NH4SO4precipitation, ultrafiltration and butanol extraction. Both compounds were characterized as bacteriocin-like inhibitory substances (BLIS). BLISm6c and BLISm387 were stable at 70°C for 30min and active in the pH range from 3 to 7. The antibacterial activity was completely lost at pH values higher than 8 or temperatures >80°C. Both BLIS have a narrow activity range and highly inhibit the growth ofP.larvae. BLISm6c and BLISm387 differ from each other and other BLIS reportedly produced byB.cereuswith regard to their molecular weights, antibacterial activity, minimal inhibitory concentration values and sensitivity to degradative enzymes. The findings of this study suggest that BLISm6c and BLISm387 can potentially be used to control AFB

An improved technique for direct visualization of plasmid patterns in strains of <i>Paenibacillus larvae</i>

American Foulbrood disease (AFB) caused by Paenibacillus larvae is the most devastating bacterial disease affecting honey bee brood worldwide. Beekeepers have been using oxytetracycline for decades to prevent and control AFB. In some countries with high disease incidence, antibiotics are still employed with the consequent risks of the appearance of tetracycline-resistant phenotypes associated with small plasmids carrying a tetracycline-resistance gene. Techniques for plasmid visualization in Gram-positive bacteria, particularly spore-forming, are not always successful. The present study aims to improve a method for direct visualization of plasmid patterns in P. larvae and other spore-forming bacteria isolated from apiarian sources. We tested 51 P. larvae strains from different geographical areas, including tetracycline-sensitive and resistant ones. The results revealed six different plasmid profiles, named I, II, III, IV, and V. Within tetracycline-resistant strains, four strains showed pattern IV with two plasmids of 5,000 and 8,000 bp, and two strains exhibited pattern V, with bands of about 5,000, 7,000, and 8,000 bp. The plasmid band of 5,000 bp present in the six resistant strains corresponds to the tetracycline-resistance mobilizable plasmid reported for P. larvae. Within the tetracycline-sensitive phenotypes, 33 strains showed no plasmids (pattern I); while two additional profiles were detected in the rest, i.e., pattern III with three plasmids in one strain and pattern VI showing two plasmids in six strains. Patterns II, III, and VI are probably related to the presence of cryptic plasmids. In conclusion, the improved technique allows us to identify plasmid patterns in P. larvae, ensuring their reproducibility and feasibility.</p