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1.
Sci Rep ; 14(1): 10079, 2024 05 02.
Article in English | MEDLINE | ID: mdl-38698037

ABSTRACT

Over the last quarter century, increasing honey bee colony losses motivated standardized large-scale surveys of managed honey bees (Apis mellifera), particularly in Europe and the United States. Here we present the first large-scale standardized survey of colony losses of managed honey bees and stingless bees across Latin America. Overall, 1736 beekeepers and 165 meliponiculturists participated in the 2-year survey (2016-2017 and 2017-2018). On average, 30.4% of honey bee colonies and 39.6% of stingless bee colonies were lost per year across the region. Summer losses were higher than winter losses in stingless bees (30.9% and 22.2%, respectively) but not in honey bees (18.8% and 20.6%, respectively). Colony loss increased with operation size during the summer in both honey bees and stingless bees and decreased with operation size during the winter in stingless bees. Furthermore, losses differed significantly between countries and across years for both beekeepers and meliponiculturists. Overall, winter losses of honey bee colonies in Latin America (20.6%) position this region between Europe (12.5%) and the United States (40.4%). These results highlight the magnitude of bee colony losses occurring in the region and suggest difficulties in maintaining overall colony health and economic survival for beekeepers and meliponiculturists.


Subject(s)
Beekeeping , Seasons , Animals , Bees/physiology , Latin America
2.
Rev Argent Microbiol ; 2024 Jan 24.
Article in English | MEDLINE | ID: mdl-38272730

ABSTRACT

Water kefir is a sparkling, slightly acidic fermented beverage made from sugar, water, and water kefir grains, which are a mixture of yeast and bacteria. These grains produce a variety of fermentation compounds such as lactic acid, acetaldehyde, acetoin, ethanol and carbon dioxide. In this study, a high-throughput sequencing technique was used to characterize the bacterial composition of the original water kefir from which potential probiotics were obtained. We studied the bacterial diversity of both water kefir grains and beverages. DNA was extracted from three replicate samples of both grains and beverages using the Powerlyzer Microbial Kit. The hypervariable V1-V2 region of the bacterial 16S ribosomal RNA gene was amplified to prepare six DNA libraries. Between 1.4M and 2.4M base-pairs were sequenced for the library. In total, 28721971 raw reads were obtained from all the samples. Estimated species richness was higher in kefir beverage samples compared to grain samples. Moreover, a higher level of microbial alpha diversity was observed in the beverage samples. Particularly, the predominant bacteria in beverages were Anaerocolumna and Ralstonia, while in grains Liquorilactobacillus dominated, with lower levels of Leuconostoc and Oenococcus. Although the bacterial diversity in kefir grains was low because only three genera were the most represented, all of them are LAB bacteria with the potential to serve as probiotics in the artificial feeding of bees.

3.
J Insect Sci ; 23(6)2023 Nov 01.
Article in English | MEDLINE | ID: mdl-38055943

ABSTRACT

Managed populations of honey bees (Apis mellifera Linnaeus; Hymenoptera: Apidae) are regularly exposed to infectious diseases. Good hive management including the occasional application of antibiotics can help mitigate infectious outbreaks, but new beekeeping tools and techniques that bolster immunity and help control disease transmission are welcome. In this review, we focus on the applications of beneficial microbes for disease management as well as to support hive health and sustainability within the apicultural industry. We draw attention to the latest advances in probiotic approaches as well as the integration of fermented foods (such as water kefir) with disease-fighting properties that might ultimately be delivered to hives as an alternative or partial antidote to antibiotics. There is substantial evidence from in vitro laboratory studies that suggest beneficial microbes could be an effective method for improving disease resistance in honey bees. However, colony level evidence is lacking and there is urgent need for further validation via controlled field trials experimentally designed to test defined microbial compositions against specific diseases of interest.


Subject(s)
Beekeeping , Bees , Fermentation , Gastrointestinal Microbiome , Probiotics , Animals , Anti-Bacterial Agents/immunology , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Beekeeping/methods , Bees/drug effects , Bees/immunology , Bees/microbiology , Fermentation/immunology , Gastrointestinal Microbiome/immunology , Probiotics/pharmacology , Probiotics/therapeutic use
4.
Rev. argent. microbiol ; 55(2): 10-10, jun. 2023. graf
Article in English | LILACS-Express | LILACS | ID: biblio-1449408

ABSTRACT

Abstract We evaluated the microbial composition of water kefir grains and beverage overthe course of one year to determine whether the number and type of microorganisms changedover the time. Bacteria and yeast colonies with different morphologies were isolated fromwater kefir and their antimicrobial activity was evaluated against Paenibacillus larvae andAscosphaera apis. A chemical characterization of kefir was also carried out. Our results con-firmed that bacteria and yeasts were more numerous in kefir grains compared with those in thebeverage. The counts of microorganisms declined, although an important microbial community was still present in kefir after the long storage period. Eleven strains which inhibited bee pathogens were isolated from kefir. Genotypic results demonstrated that these isolates included Lentilactobacillus hilgardii, Lentilactobacillus buchneri and Saccharomyces cerevisiae. Thus, water kefir may be an innovative source of potential probiotic strains for bee nutrition in order to control honeybee diseases.


Resumen Evaluamos la composición microbiana del kéfir de agua durante un ano para determinar si la cantidad y el tipo de microorganismos cambiaban con el tiempo. Se aislaron colonias de bacterias y de levaduras con diferentes morfologías, y su actividad antimicrobiana se evaluó frente a Paenibacillus larvaey Ascosphaeraapis. También se realizó una caracterización química del kéfir. Nuestros resultados confirmaron que las bacterias y las levaduras eran más numerosas en los gránulos de kéfir en comparación con la parte líquida. Los recuentos de microorganismos disminuyeron, aunque una cantidad igualmente importante se encontró en el kéfir después de un año. Se aislaron del kéfir once cepas que inhibieron los mencionados patógenos de abejas. Los resultados genotípicos demostraron que estos aislamientos eran Lentilactobacillus hilgardii, Lentilactobacillus buchneri y Saccharomyces cerevisiae. Por lo tanto, el kéfir de agua podría ser una fuente innovadora de potenciales cepas probióticas para contribuir a la nutrición y sanidad de las abejas.

5.
Rev Argent Microbiol ; 55(2): 176-180, 2023.
Article in English | MEDLINE | ID: mdl-36481105

ABSTRACT

We evaluated the microbial composition of water kefir grains and beverage over the course of one year to determine whether the number and type of microorganisms changed over the time. Bacteria and yeast colonies with different morphologies were isolated from water kefir and their antimicrobial activity was evaluated against Paenibacillus larvae and Ascosphaera apis. A chemical characterization of kefir was also carried out. Our results confirmed that bacteria and yeasts were more numerous in kefir grains compared with those in the beverage. The counts of microorganisms declined, although an important microbial community was still present in kefir after the long storage period. Eleven strains which inhibited bee pathogens were isolated from kefir. Genotypic results demonstrated that these isolates included Lentilactobacillus hilgardii, Lentilactobacillus buchneri and Saccharomyces cerevisiae. Thus, water kefir may be an innovative source of potential probiotic strains for bee nutrition in order to control honeybee diseases.


Subject(s)
Kefir , Probiotics , Bees , Animals , Kefir/microbiology , Water , Beverages/microbiology , Bacteria , Saccharomyces cerevisiae , Fermentation
6.
Vet Parasitol Reg Stud Reports ; 26: 100624, 2021 12.
Article in English | MEDLINE | ID: mdl-34879936

ABSTRACT

Intensive use of macrocyclic lactones for parasite control exerts strong selective pressure for arthropods such as ticks to become resistant to them. Rhipicephalus sanguineus sensu stricto is a tick and disease vector of significant public health and veterinary importance worldwide. We assessed the toxicological response to the macrocyclic lactone ivermectin (IVM) in R. sanguineus s.s. infesting dogs in Argentina. Samples of nine tick populations were obtained by inspecting dogs at veterinary clinics, hospitals, or rural areas in the provinces of San Luis, Rio Negro, and Buenos Aires. Pet owners were interviewed to gather data on the history of dog treatment with ectoparasiticides. The larval immersion test was used to assess the toxicological response of R. sanguineus s.s. to IVM. Dose-response mortality regressions, lethal concentrations (LC), and slope were calculated by probit analysis. The lowest LC concentrations were used to designate the reference susceptible population because a laboratory reference strain of R. sanguineus s.s. does not exist in Argentina. Compared with the most susceptible tick population in this study, six populations (66.66%) were classified as resistant to IVM. A clear interpopulation variation in the level of IVM resistance was present (resistance ratios at LC50% ranged from 1.0 to 18.33 and at LC99% ranged from 1.0 to 8.96). In San Luis Province, all tick populations were classified as resistant. The highest level of IVM resistance (resistance ratio at LC50%:18.83 and LC99%:8.96) was found in a population of R. sanguineus s.s. from a rural area in the province of Buenos Aires. It is concluded that populations of R. sanguineus s.s. from dogs in three provinces of Argentina were resistant to IVM. Clear interpopulation variation in the level of IVM resistance was present.


Subject(s)
Dog Diseases , Rhipicephalus sanguineus , Tick Infestations , Animals , Argentina , Dog Diseases/parasitology , Dogs , Ivermectin/pharmacology , Larva , Tick Infestations/drug therapy , Tick Infestations/epidemiology , Tick Infestations/veterinary
7.
Arch Virol ; 166(6): 1533-1545, 2021 Jun.
Article in English | MEDLINE | ID: mdl-33683476

ABSTRACT

Beekeeping is a widespread activity in Argentina, mainly producing honey that has gained both national and international recognition. There are more than 3,000,000 hives in the country, mainly concentrated in Buenos Aires Province (approximately 1,000,000 hives). In recent decades, worrying rates of hive loss have been observed in many countries around the world. In Latin America, the estimated loss of hives is between 13% (Peru and Ecuador) and 53% (Chile). Argentina had annual losses of 34% for the period of October 1, 2016 to October 1, 2017. The causes of these losses are not clear but probably involve multiple stressors that can act simultaneously. One of the main causes of loss of bee colonies worldwide is infestation by the ectoparasitic mite Varroa destructor in combination with viral infections. To date, 10 viruses have been detected that affect honey bees (Apis mellifera) in Argentina. Of these, deformed wing virus, sacbrood virus, acute bee paralysis virus, chronic bee paralysis virus, and Israeli acute bee paralysis can be transmitted by mites. Deformed wing virus and the AIK complex are the viruses most often associated with loss of hives worldwide. Considering that bee viruses have been detected in Argentina in several hymenopteran and non-hymenopteran insects, these hosts could act as important natural reservoirs for viruses and play an important role in their dispersal in the environment. Further studies to investigate the different mechanisms by which viruses spread in the environment will enable us to develop various strategies for the control of infected colonies and the spread of viruses in the habitat where they are found.


Subject(s)
Bees/virology , Animals , Argentina , DNA Viruses/genetics , DNA Viruses/isolation & purification , Host-Pathogen Interactions , RNA Viruses/genetics , RNA Viruses/isolation & purification
8.
Med Mycol Case Rep ; 16: 4-7, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28386526

ABSTRACT

A 2-year-old female Border collie was examined for dermatitis with a partial alopecic zone around her left front member. Six months later the lesion became swollen, alopecic with ulcerated areas. Microscopy analysis of samples showed numerous non-septate, branching, thin-walled and irregular shaped hyphal elements. Fungal cultures and molecular studies identified Saksenaea vasiformis. Treatments with griseofulvin, itraconazole and surgical debridement were used, however, fourteen months later the dog was euthanatized because of the unfavorable clinical outcome.

9.
Rev. iberoam. micol ; 32(4): 261-264, oct.-dic. 2015.
Article in English | IBECS | ID: ibc-143446

ABSTRACT

Background. Nowadays several invertebrate pollinators of crops and wild plants are in decline as result of multiple and, sometimes, unknown factors; among them, the modern agricultural practices, pests and diseases are postulated as the most important factors. Bees of the genus Xylocopa are considered effective pollinators of passion fruit crops in tropical regions, as well as important pollinators in wild plants, but these bees are attacked by several pathogens that affect different stages in their life cycle. The fungal species of the genus Ascosphaera are commonly associated with social and solitary bee larvae causing chalkbrood disease. Aims. The aim of the present study was to demonstrate the presence of Ascosphaera apis affecting larvae of Xylocopa augusti in South America. Methods. For this purpose, A. apis was isolated from affected larvae in YGPSA medium. Final identification was run out by three techniques: (1) Microscopic examination of the hyphae and sizes of the fruiting bodies; (2) Mating test, and specific sexual compatibility test, and (3) PCR detection, using specific primers. Results. This study demonstrates for the first time the presence of A. apis affecting larvae of X. augusti in South America. Conclusions. The evidence of A. apis affecting the larvae of X. augusti, and the fact that the sharing of pathogens between different bee species has been underestimated, suggests the need for further epidemiological studies in order to determine not only the prevalence of this pathogen among wild pollinators, but also its relationship to the sudden collapse of honey bee colonies in this region (AU)


Antecedentes. En la actualidad, las poblaciones de una gran cantidad de insectos polinizadores están disminuyendo debido a múltiples factores, no siempre conocidos, como las prácticas agrícolas modernas, las plagas y las nuevas enfermedades. Las abejas del género Xylocopa se consideran unos importantes polinizadores de los cultivos de maracuyá en el trópico, así como de gran cantidad de plantas silvestres. Estos polinizadores silvestres se ven afectados por diversos agentes patógenos en diferentes etapas de su ciclo de vida. En particular, varias especies del hongo entomopatógeno Ascosphaera están comúnmente asociadas a las larvas de abejas sociales y solitarias, en las que causan una infección conocida como cría yesificada. Objetivos. El objetivo del presente estudio fue demostrar la presencia de Ascosphaera apis en larvas de Xylocopa augusti en Sudamérica. Métodos. Se aisló A. apis de las larvas afectadas en medio YGPSA. La identificación final fue realizada utilizando tres técnicas: 1) examen microscópico del tamaño de las hifas y los cuerpos de fructificación; 2) test de apareamiento y test específico de compatibilidad sexual, y 3) detección mediante PCR, utilizando iniciadores específicos. Resultados. En este estudio se ha registrado por primera vez en Sudamérica la presencia de A. apis en larvas enfermas de la abeja nativa X. augusti. Conclusiones. La presencia de A. apis en larvas enfermas de X. augusti, sumada al hecho de que se ha subestimado la presencia de los mismos patógenos en diferentes especies de abejas, evidencia la necesidad de realizar más estudios epidemiológicos para determinar no solo la prevalencia de este patógeno entre polinizadores silvestres, sino también su relación con el repentino colapso de las colonias de abejas de la miel en esta región (AU)


Subject(s)
Animals , Bees/parasitology , Mycoses/veterinary , Insecta/parasitology , South America/epidemiology , Antifungal Agents/therapeutic use
10.
Rev Iberoam Micol ; 32(4): 261-4, 2015.
Article in English | MEDLINE | ID: mdl-25959551

ABSTRACT

BACKGROUND: Nowadays several invertebrate pollinators of crops and wild plants are in decline as result of multiple and, sometimes, unknown factors; among them, the modern agricultural practices, pests and diseases are postulated as the most important factors. Bees of the genus Xylocopa are considered effective pollinators of passion fruit crops in tropical regions, as well as important pollinators in wild plants, but these bees are attacked by several pathogens that affect different stages in their life cycle. The fungal species of the genus Ascosphaera are commonly associated with social and solitary bee larvae causing chalkbrood disease. AIMS: The aim of the present study was to demonstrate the presence of Ascosphaera apis affecting larvae of Xylocopa augusti in South America. METHODS: For this purpose, A. apis was isolated from affected larvae in YGPSA medium. Final identification was run out by three techniques: (1) Microscopic examination of the hyphae and sizes of the fruiting bodies; (2) Mating test, and specific sexual compatibility test, and (3) PCR detection, using specific primers. RESULTS: This study demonstrates for the first time the presence of A. apis affecting larvae of X. augusti in South America. CONCLUSIONS: The evidence of A. apis affecting the larvae of X. augusti, and the fact that the sharing of pathogens between different bee species has been underestimated, suggests the need for further epidemiological studies in order to determine not only the prevalence of this pathogen among wild pollinators, but also its relationship to the sudden collapse of honey bee colonies in this region.


Subject(s)
Ascomycota/isolation & purification , Bees/microbiology , Animals , Argentina , Ascomycota/ultrastructure , Bees/growth & development , Hyphae/ultrastructure , Larva/microbiology , Species Specificity , Spores, Fungal
11.
Rev. argent. microbiol ; 45(4): 257-61, dic. 2013.
Article in Spanish | LILACS, BINACIS | ID: biblio-1171796

ABSTRACT

American foulbrood (AFB) is a bacterial disease caused by the spore-forming, grampositive bacterium Paenibacillus larvae, which affects honeybee broods worldwide. The aim of this work was to compare the Epsilometer test (Etest) to the agar dilution method for testing a collection of 22 P. larvae strains to tetracycline by using MYPGP and Iso- Sensitest agars. Results showed that a categorical agreement of 100


was found when using Iso-Sensitest, while a categorical agreement of 86.36


was found (with 3 minor errors) when MYPGP was tested. In conclusion, the Etest could be a rapid and reliable method for testing MIC values of tetracycline in P. larvae only when used in combination with Iso-Sensitest agar. Nevertheless, these results should be confirmed with future studies involving a larger number of isolates.


Subject(s)
Anti-Bacterial Agents/pharmacology , Paenibacillus/drug effects , Tetracycline/pharmacology , Bees/microbiology , Animals , Gram-Positive Bacterial Infections , Microbial Sensitivity Tests/methods
12.
Rev Argent Microbiol ; 45(4): 257-61, 2013.
Article in Spanish | MEDLINE | ID: mdl-24401780

ABSTRACT

American foulbrood (AFB) is a bacterial disease caused by the spore-forming, grampositive bacterium Paenibacillus larvae, which affects honeybee broods worldwide. The aim of this work was to compare the Epsilometer test (Etest) to the agar dilution method for testing a collection of 22 P. larvae strains to tetracycline by using MYPGP and Iso- Sensitest agars. Results showed that a categorical agreement of 100% was found when using Iso-Sensitest, while a categorical agreement of 86.36% was found (with 3 minor errors) when MYPGP was tested. In conclusion, the Etest could be a rapid and reliable method for testing MIC values of tetracycline in P. larvae only when used in combination with Iso-Sensitest agar. Nevertheless, these results should be confirmed with future studies involving a larger number of isolates.


Subject(s)
Anti-Bacterial Agents/pharmacology , Paenibacillus/drug effects , Tetracycline/pharmacology , Animals , Bees/microbiology , Gram-Positive Bacterial Infections , Microbial Sensitivity Tests/methods
13.
Rev. Argent. Microbiol. ; 45(4): 257-61, 2013 Oct-Dec.
Article in Spanish | BINACIS | ID: bin-132752

ABSTRACT

American foulbrood (AFB) is a bacterial disease caused by the spore-forming, grampositive bacterium Paenibacillus larvae, which affects honeybee broods worldwide. The aim of this work was to compare the Epsilometer test (Etest) to the agar dilution method for testing a collection of 22 P. larvae strains to tetracycline by using MYPGP and Iso- Sensitest agars. Results showed that a categorical agreement of 100


was found when using Iso-Sensitest, while a categorical agreement of 86.36


was found (with 3 minor errors) when MYPGP was tested. In conclusion, the Etest could be a rapid and reliable method for testing MIC values of tetracycline in P. larvae only when used in combination with Iso-Sensitest agar. Nevertheless, these results should be confirmed with future studies involving a larger number of isolates.


Subject(s)
Anti-Bacterial Agents/pharmacology , Paenibacillus/drug effects , Tetracycline/pharmacology , Animals , Bees/microbiology , Gram-Positive Bacterial Infections , Microbial Sensitivity Tests/methods
14.
Rev Argent Microbiol ; 43(2): 84-6, 2011.
Article in English | MEDLINE | ID: mdl-21731968

ABSTRACT

Honey bee mortality has recently been associated with Israeli acute paralysis virus (IAPV), a proposed etiological agent for a new syndrome known as Colony Collapse Disorder. Bees infected with this virus show shivering wings, progress into paralysis, and finally die outside the hive. During the last years, honey bee mortality became a serious problem for Argentinean beekeepers. We herein report the preliminary results of a survey carried out to detect IAPV in samples taken from several Argentine provinces, by using a reverse transcription Polymerase Chain Reaction assay. Our data indicate the existence of high frequency of IAPV in asymptomatic hives of Argentina.


Subject(s)
Bees/virology , Colony Collapse/virology , Dicistroviridae/isolation & purification , Animals , Argentina/epidemiology , Colony Collapse/epidemiology , Female , Reverse Transcriptase Polymerase Chain Reaction , Sampling Studies
15.
Rev. argent. microbiol ; 43(2): 84-86, jun. 2011. ilus, tab
Article in English | LILACS | ID: lil-634676

ABSTRACT

Honey bee mortality has recently been associated with Israeli acute paralysis virus (IAPV), a proposed etiological agent for a new syndrome known as Colony Collapse Disorder. Bees infected with this virus show shivering wings, progress into paralysis, and finally die outside the hive. During the last years, honey bee mortality became a serious problem for Argentinean beekeepers. We herein report the preliminary results of a survey carried out to detect IAPV in samples taken from several Argentine provinces, by using a reverse transcription Polymerase Chain Reaction assay. Our data indicate the existence of high frequency of IAPV in asymptomatic hives of Argentina.


Recientemente la mortalidad de las abejas melíferas ha sido asociada al virus israelí de la parálisis aguda (IAPV), propuesto como agente etiológico del denominado síndrome de despoblamiento de las colmenas. Las abejas infectadas con este virus presentan temblores en las alas que progresan hasta convertirse en parálisis, y finalmente mueren fuera de la colmena. Durante los últimos años, la mortalidad de las abejas melíferas se ha transformado en un serio problema para los productores de miel de la Argentina. Nosotros informamos aquí los resultados preliminares de un estudio realizado para detectar IAPV en muestras de colmenas provenientes de varias provincias argentinas utilizando la técnica de transcripción reversa-reacción en cadena de la polimerasa. Nuestros datos indican la presencia de IAPV en un alto porcentaje de las colonias estudiadas.


Subject(s)
Animals , Female , Bees/virology , Colony Collapse/virology , Dicistroviridae/isolation & purification , Argentina/epidemiology , Colony Collapse/epidemiology , Reverse Transcriptase Polymerase Chain Reaction , Sampling Studies
16.
Vet Microbiol ; 132(1-2): 119-28, 2008 Nov 25.
Article in English | MEDLINE | ID: mdl-18539412

ABSTRACT

American Foulbrood (AFB) of honeybees (Apis mellifera L.), caused by the Gram-positive bacterium Paenibacillus larvae is one of the most serious diseases affecting the larval and pupal stages of honeybees (A. mellifera L.). The aim of the present work was to asses the response of 23 strains of P. larvae from diverse geographical origins to tilmicosin, a macrolide antibiotic developed for exclusive use in veterinary medicine, by means of the minimal inhibitory concentration (MIC) and the agar diffusion test (ADT). All the strains tested were highly susceptible to tilmicosin with MIC values ranging between 0.0625 and 0.5 microg ml(-1), and with MIC(50) and MIC(90) values of 0.250 microg ml(-1). The ADT tests results for 23 P. larvae strains tested showed that all were susceptible to tilmicosin with inhibition zones around 15 microg tilmicosin disks ranging between 21 and 50mm in diameter. Oral acute toxicity of tilmicosin was evaluated and the LD(50) values obtained demonstrated that it was virtually non-toxic for adult bees and also resulted non-toxic for larvae when compared with the normal brood mortality. Dosage of 1000 mg a.i. of tilmicosin applied in a 55 g candy resulted in a total suppression of AFB clinical signs in honeybee colonies 60 days after initial treatment. To our knowledge, this is the first report of the effectiveness of tilmicosin against P. larvae both in vitro and in vivo.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Bees/microbiology , Gram-Positive Bacteria/drug effects , Tylosin/analogs & derivatives , Animals , Anti-Bacterial Agents/adverse effects , Bees/drug effects , Drug Resistance, Bacterial , Larva/microbiology , Microbial Sensitivity Tests , Pupa/microbiology , Tylosin/adverse effects , Tylosin/therapeutic use
17.
Vet Microbiol ; 125(3-4): 290-303, 2007 Dec 15.
Article in English | MEDLINE | ID: mdl-17601687

ABSTRACT

Paenibacillus larvae is the causal agent of American Foulbrood (AFB) disease, the most virulent bacterial disease of honeybee (Apis mellifera L.) brood. Oxytetracycline is the main antibiotic used for prevention and control of AFB. Using the polymerase chain reaction, isolates were screened for the presence of the tetracycline resistance tet(K) and tet(L) determinants. Four isolates (5%), which correlated with the Tc-resistant phenotypes, were found to carry the tet(K) determinant, whereas none carried the tet(L) determinant. P. larvae cells were also screened for the presence of extrachromosomal DNA and evidence obtained that tetracycline resistance is plasmid-encoded. A few P. larvae isolates were found to be able to transfer the tet(K) determinant to Bacillus subtilis, suggesting that a conjugation mechanism may be involved in the transfer of the tetracycline-resistant phenotype. Minimum inhibitory concentrations to tetracycline were determined for 75 isolates of P. larvae from different geographical origins and found to range between 0.062 and 128 microg tetracyclineml(-1), with MIC(50) and MIC(90) values of 1 and 4, respectively. According to results from P. larvae populations, isolates could be considered as susceptible when their MICs were <4, intermediate for MICs values 4-8 and resistant for MICs > or = 16. To our knowledge, this is the first report of Tc(r)Paenibacillus species carrying a tet(K) gene, and also the first record of P. larvae strains carrying tet(K) determinants and its correlation with the presence of extrachromosomal DNA.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacillus/growth & development , Bees/microbiology , Gram-Positive Bacterial Infections/microbiology , Oxytetracycline/pharmacology , Tetracycline Resistance/genetics , Animals , Anti-Bacterial Agents/therapeutic use , Bacillus/drug effects , Bacillus/genetics , Conjugation, Genetic/drug effects , Conjugation, Genetic/genetics , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , Gram-Positive Bacterial Infections/drug therapy , Microbial Sensitivity Tests/veterinary , Oxytetracycline/therapeutic use , Plasmids/genetics , Polymerase Chain Reaction/veterinary
18.
J Invertebr Pathol ; 91(3): 141-6, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16458322

ABSTRACT

The bacterium Paenibacillus larvae, the causative agent of American foulbrood disease of honeybee larvae, occurs throughout the world and is found in many beekeeping areas of Argentina. The potential as biocontrol agents of antagonic aerobic spore-forming bacteria isolated from honey samples and other apiarian sources were evaluated. Each isolate was screened against one strain of Paenibacillus larvae (ATCC 9545) by using a perpendicular streak technique. Ten randomly selected bacterial strains from the group that showed the best antagonistic effect to P. larvae ATCC 9545 were selected for further study. These were identified as Bacillus subtilis (m351), B. pumilus (m350), B. licheniformis (m347), B. cereus (mv33), B. cereus (m387), B. cereus (m6c), B. megaterium (m404), Brevibacillus laterosporus (BLAT169), B. laterosporus (BLAT170), and B. laterosporus (BLAT171). The antagonistic strains were tested against 17 P. larvae strains from different geographical origins by means of a spot test in wells. The analysis of variance and posterior comparison of means by Tukey method (P < 0.01) showed that the best antagonists were B. megaterium (m404), B. licheniformis (m347), B. cereus (m6c), B. cereus (mv33), and B. cereus (m387).


Subject(s)
Bacillus/classification , Bacillus/growth & development , Bacteria, Aerobic/physiology , Bees/microbiology , Pest Control, Biological , Spores, Bacterial/physiology , Animals , Bacillus cereus/growth & development , Bacterial Typing Techniques , Bacteriological Techniques , Honey/microbiology , Larva/growth & development , Larva/microbiology
19.
Vet Microbiol ; 109(1-2): 47-55, 2005 Aug 10.
Article in English | MEDLINE | ID: mdl-15951140

ABSTRACT

The minimal inhibitory concentrations (MICs) of tylosin were determined to 67 strains of Paenibacillus larvae subsp. larvae, the causal agent of American Foulbrood (AFB) disease, from different geographical origins. MIC values obtained ranged from 0.0078 to 0.5 microg/ml. These very low values imply that no resistance to tylosin was found in any isolate of the Foulbrood pathogen. The measurement of diseased larvae with AFB-clinical symptoms in three different field studies demonstrated that tylosin treatment could be effective in vivo. No negative effects in colonies were noted at any dosage rates or forms of application. These studies demonstrate that tylosin, as tartrate, can be used to treat AFB in honeybee colonies.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacillus/drug effects , Bacterial Infections/veterinary , Bees/microbiology , Tylosin/pharmacology , Animals , Anti-Bacterial Agents/therapeutic use , Argentina , Bacillus/growth & development , Bacillus/isolation & purification , Bacterial Infections/drug therapy , Bacterial Infections/microbiology , Dose-Response Relationship, Drug , Female , Microbial Sensitivity Tests , Statistics, Nonparametric , Tylosin/therapeutic use
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