RESUMO
BACKGROUND: A detailed laboratory investigation identified bovine coronavirus (BCoV) as the aetiological agent in an outbreak of respiratory disease at a semi-intensive beef cattle feedlot in south-east Australia. The outbreak caused 30% morbidity in the resident population and also affected two cohorts of cattle that were newly introduced to the property. METHODS: At slaughter, pulmonary consolidation and inflammatory lesions in the trachea were identified in 15 of 49 animals. Pasteurella multocida or Histophilus somni was cultured from 3 of 7 animals with lesions. Histopathological examination revealed multifocal non-suppurative bronchointerstitial pneumonia with formation of epithelial syncytial cells, sometimes associated with suppurative bronchopneumonia. RESULTS: BCoV was detected in nasal swabs and pulmonary lesions using real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) assay and virus isolation. There was serological evidence of previous exposure to bovine viral diarrhoea virus, bovine respiratory syncytial virus and bovine parainfluenza virus type 3, but not to bovine herpesvirus type 1. None of these viral pathogens or Mycoplasma bovis was identified by qRT-PCR. CONCLUSION: This is believed to be the first report of BCoV in association with bovine respiratory disease complex in Australia.
Assuntos
Doenças dos Bovinos/diagnóstico , Infecções por Coronavirus/veterinária , Coronavirus Bovino/isolamento & purificação , Infecções Respiratórias/veterinária , Criação de Animais Domésticos/métodos , Animais , Austrália/epidemiologia , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/virologia , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/epidemiologia , Surtos de Doenças/veterinária , Cavidade Nasal/virologia , Infecções Respiratórias/diagnóstico , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/virologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterináriaRESUMO
Intensive livestock production is associated with an increased incidence of salmonellosis. The risk of infection and the subsequent public health concern is attributed to increased pathogen exposure and disease susceptibility due to multiple stressors experienced by livestock from farm to feedlot. Traditional parenteral vaccine methods can further stress susceptible populations and cause carcass damage, adverse reactions, and resultant increased production costs. As a potential means to address these issues, in-water delivery of live attenuated vaccines affords a low cost, low-stress method for immunization of livestock populations that is not associated with the adverse handling stressors and injection reactions associated with parenteral administration. We have previously established that in-water administration of a Salmonella enterica serovar Typhimurium dam vaccine conferred significant protection in livestock. While these experimental trials hold significant promise, the ultimate measure of the vaccine will not be established until it has undergone clinical testing in the field wherein environmental and sanitary conditions are variable. Here we show that in-water administration of a S. Typhimurium dam attenuated vaccine was safe, stable, and well-tolerated in adult sheep. The dam vaccine did not alter water consumption or vaccine dosing; remained viable under a wide range of temperatures (21-37°C); did not proliferate within fecal-contaminated trough water; and was associated with minimal fecal shedding and clinical disease as a consequence of vaccination. The capacity of Salmonella dam attenuated vaccines to be delivered in drinking water to protect livestock from virulent Salmonella challenge offers an effective, economical, stressor-free Salmonella prophylaxis for intensive livestock production systems.
Assuntos
Salmonelose Animal/prevenção & controle , Vacinas contra Salmonella/administração & dosagem , Vacinas contra Salmonella/imunologia , Salmonella typhimurium/genética , Salmonella typhimurium/imunologia , Doenças dos Ovinos/prevenção & controle , DNA Metiltransferases Sítio Específica (Adenina-Específica)/deficiência , Administração Oral , Animais , Derrame de Bactérias , Água Potável/microbiologia , Viabilidade Microbiana , Vacinas contra Salmonella/efeitos adversos , Salmonella typhimurium/enzimologia , Ovinos , Temperatura , Vacinação/métodos , Vacinas Atenuadas/administração & dosagem , Vacinas Atenuadas/efeitos adversos , Vacinas Atenuadas/imunologiaRESUMO
Stimulation of acquired immunity to Salmonella in livestock is not feasible in neonates (which can be infected within 24h of birth) and is challenging in feedlots, which typically source animals from diverse locations and vendors. Induction of innate immune mechanisms through mass vaccination of animals upon arrival to feedlots is an alternative approach. Transport, environmental conditions, changes in social grouping, and further handling during feedlot assembly are significant stressors. These factors, as well as concurrent exposure to a diversity of pathogens, contribute to the risk of disease. We have shown that oral immunization of calves with a modified live Salmonella enterica serovar Typhimurium vaccine strain, which lacks the DNA adenine methylase gene (S. Typhimurium dam), attenuates the severity of clinical disease, reduces fecal shedding, and promotes clearance of salmonellae following virulent homologous and heterologous challenge. This study examines the safety and efficacy of a S. Typhimurium dam vaccine in sheep via oral delivery in drinking water (ad libitum), as a means to effectively vaccinate large groups of animals. Adult merino sheep were vaccinated in drinking water -28 days, -7 days and 24h pre and 24h post-virulent Salmonella Typhimurium challenge which was administered via the oral route. Significant attenuation of clinical disease (temperature, appetite, and attitude) and reduction in mortality and virulent Salmonella Typhimurium fecal shedding and tissue colonization was observed in animals that received the vaccine 28 and 7 days pre-challenge. Further, vaccination did not pose a risk to stock previously infected with virulent salmonellae as mortalities and clinical disease in sheep vaccinated prior to or following virulent challenge did not differ significantly from the non-vaccinated controls. The capacity of S. Typhimurium dam vaccines delivered in drinking water to protect livestock from virulent Salmonella challenge offers an effective, economical, stressor free Salmonella prophylaxis for intensive livestock production systems.
Assuntos
Salmonelose Animal/imunologia , Salmonelose Animal/prevenção & controle , Vacinas contra Salmonella/imunologia , Ovinos/imunologia , Vacinas de DNA/imunologia , Animais , Fezes/microbiologia , Pulmão/imunologia , Linfonodos/imunologia , Masculino , Salmonella typhimurium/genética , Salmonella typhimurium/imunologia , Ovinos/microbiologia , DNA Metiltransferases Sítio Específica (Adenina-Específica)/genéticaRESUMO
Intensive livestock production and management systems are associated with increased fecal-oral pathogen transmission and a resultant high prevalence of multiple Salmonella serovars in many large dairy farms and feedlots. Thus, it is imperative to develop livestock vaccines that are capable of eliciting potent states of cross-protective immunity against a diversity of serovars of a given species. Immunization with modified live Salmonella enterica serovar Typhimurium vaccine strains, that lack the DNA adenine methylase (Dam), confers cross-protective immunity in murine and avian models of typhoid fever as well as in a bovine model of salmonellosis. Here we examined whether a dam mutant Typhimurium vaccine (serogroup B) has the capacity to elicit cross-protection against a virulent challenge with an emerging, clinically relevant, and multi-drug resistant strain of serovar Newport (serogroup C2-C3) that has been associated with clinical disease in recent salmonellosis outbreaks in calves. Vaccinated animals challenged with Newport exhibited a significant attenuation of clinical disease (improved attitude scores, increased daily weight gains and reduced fever and diarrhea) and a concomitant reduction in Newport fecal shedding and colonization of mesenteric lymph nodes and lungs compared to non-vaccinated control animals. The capacity to elicit cross-protective immunity in calves suggests that dam mutant vaccines have potential application toward the prevention and control of Salmonella infection in commercial livestock production systems wherein livestock are exposed to a diversity of Salmonella serovars.
Assuntos
Doenças dos Bovinos/imunologia , Salmonelose Animal/imunologia , Vacinas contra Salmonella/genética , Vacinas contra Salmonella/imunologia , Salmonella typhimurium/genética , Salmonella typhimurium/imunologia , DNA Metiltransferases Sítio Específica (Adenina-Específica)/genética , Animais , Bovinos , Doenças dos Bovinos/prevenção & controle , Reações Cruzadas , Fezes/microbiologia , Imunidade/imunologia , Pulmão/microbiologia , Linfonodos/microbiologia , Mesentério/microbiologia , Salmonelose Animal/prevenção & controleRESUMO
AIM: To confirm the reliability and sensitivity of Salmonella testing of processed poultry in Australia. METHODS AND RESULTS: The detection of Salmonella in a whole carcass wash of 90 randomly selected processed broilers was compared using the Australian Standard method, an Australian industry method used by a major processor and the United States Department of Agriculture method published in the Federal Register. The sensitivity of each method was determined using a carcass wash containing a known number of Salmonella Typhimurium to determine the minimum concentration to be able to be identified as positive. The two Australian methods were found to be comparable with both the Australian methods detecting more positive carcasses than the United States Department of Agriculture (USDA) method. The Australian methods were sensitive at the level of 1-3 CFU ml(-1) and the USDA method was sensitive at 10-30 CFU ml(-1). CONCLUSIONS: The Australian Standard method and the Australian industry method were both able to detect Salmonella reliably even at a low level of contamination. SIGNIFICANCE AND IMPACT OF THE STUDY: This study gives a high level of confidence both to the operators of poultry-processing plants and to regulators dependent upon the outcome of Salmonella testing for process control in Australia.
Assuntos
Técnicas Bacteriológicas/métodos , Galinhas/microbiologia , Salmonella/isolamento & purificação , Animais , Austrália , Microbiologia de Alimentos , Reprodutibilidade dos Testes , Estados UnidosRESUMO
OBJECTIVE: An epidemiological study was undertaken at a Hunter Valley dairy with persistent Salmonella Typhimurium infection. The aim of the study was to identify cattle currently or previously infected with Salmonella, possible sources of the organism, patterns of spread, and husbandry practices that could be improved. METHODOLOGY: Faecal samples, feed, water and environmental samples were cultured for Salmonella and blood samples were tested for antibodies against Salmonella (Dublin and Typhimurium). A questionnaire was designed to identify possible risk factors associated with Salmonella excretion. RESULTS: S Typhimurium was apparently introduced from an old to a new dairy through manure spread as fertiliser. Salmonella apparently persisted in the effluent pond, and the following year clinical cases occurred after pasture, irrigated with water from the pond, was grazed by dry cows, and adult cattle became clinically ill with salmonellosis. The disease spread to other cows and calves. Poor design of calf pens assisted spread of Salmonella from sick to healthy calves. In addition, there was suspected transmission to the dairy farmer's 9-month-old daughter. Salmonellosis on a farm is a potential zoonotic risk to farm workers and their families. There is also the risk that cull cows may carry Salmonella to the abattoir and subsequently into the human food chain. Methods of waste management, and the design of calf pens, were identified as major risk factors that could be improved to minimise the spread of salmonellosis on this property.
Assuntos
Anticorpos Antibacterianos/sangue , Doenças dos Bovinos/transmissão , Indústria de Laticínios/métodos , Salmonelose Animal/transmissão , Salmonella typhimurium/isolamento & purificação , Zoonoses , Ração Animal/microbiologia , Animais , Bovinos , Doenças dos Bovinos/epidemiologia , Criança , Contagem de Colônia Microbiana , Microbiologia Ambiental , Fezes/microbiologia , Feminino , Abrigo para Animais , Humanos , Higiene , Fatores de Risco , Salmonelose Animal/epidemiologia , Salmonella typhimurium/crescimento & desenvolvimento , Salmonella typhimurium/imunologia , Estudos Soroepidemiológicos , Microbiologia da ÁguaRESUMO
OBJECTIVE: To examine healthy slaughter-age cattle and sheep on-farm for the excretion of Salmonella serovars in faeces and to identify possible risk factors using a questionnaire. PROCEDURE: The study involved 215 herds and flocks in the four eastern states of Australia, 56 with prior history of salmonellosis. Production systems examined included pasture beef cattle, feedlot beef cattle, dairy cattle, prime lambs and mutton sheep and animals were all at slaughter age. From each herd or flock, 25 animals were sampled and the samples pooled for Salmonella culture. All Salmonella isolated were serotyped and any Salmonella Typhimurium isolates were phage typed. Questionnaires on each production system, prepared in Epi Info 6.04, were designed to identify risk factors associated with Salmonella spp excretion, with separate questionnaires designed for each production system. RESULTS: Salmonellae were identified in all production systems and were more commonly isolated from dairies and beef feedlots than other systems. Statistical analysis revealed that dairy cattle were significantly more likely to shed Salmonella in faeces than pasture beef cattle, mutton sheep and prime lambs (P<0.05). A wide diversity of Salmonella serovars, all of which have been isolated from humans in Australia, was identified in both cattle and sheep. Analysis of the questionnaires showed access to new arrivals was a significant risk factor for Salmonella excretion on dairy properties. For beef feedlots, the presence of large numbers of flies in the feedlot pens or around stored manure were significant risk factors for Salmonella excretion. CONCLUSION: Dairy cattle pose the highest risk of all the slaughter-age animals tested. Some of the identified risk factors can be overcome by improved management practices, especially in relation to hygiene.
Assuntos
Criação de Animais Domésticos/métodos , Doenças dos Bovinos/epidemiologia , Salmonelose Animal/epidemiologia , Salmonella/isolamento & purificação , Doenças dos Ovinos/epidemiologia , Animais , Austrália/epidemiologia , Técnicas de Tipagem Bacteriana/veterinária , Bovinos , Indústria de Laticínios/métodos , Fezes/microbiologia , Feminino , Higiene , Masculino , Fatores de Risco , Salmonella/classificação , Ovinos , Inquéritos e QuestionáriosRESUMO
OBJECTIVE: To develop a multiplex polymerase chain reaction (PCR) assay for the rapid detection of Brucella ovis, Actinobacillus seminis, Histophilus somni in fresh ram semen samples. DESIGN: The multiplex assay was based on the single PCR assays published for the detection of A seminis and B ovis, and the forward primer published for the detection of H somni; an alternative reverse primer for H somni was designed in this study. PROCEDURE: Culture and PCR of 295 fresh semen samples were carried out. RESULTS: The multiplex PCR was far more successful in the detection of H somni (45/295) than culture (23/295). A seminis was also detected in more semen samples by multiplex PCR (29/295) than culture (13/295) and B ovis was detected in three samples using both PCR and culture. No amplifications were detected with DNA from a range of bacterial isolates including species associated with epididymitis in rams. CONCLUSION: This PCR could be used as a complementary test, or alternative to culture of ram semen and other biological samples for the detection B ovis, H somni and A seminis.
Assuntos
Actinobacillus seminis/isolamento & purificação , Brucella ovis/isolamento & purificação , Pasteurellaceae/isolamento & purificação , Reação em Cadeia da Polimerase/veterinária , Sêmen/microbiologia , Animais , Contagem de Colônia Microbiana/veterinária , DNA Bacteriano/análise , Masculino , Reação em Cadeia da Polimerase/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , OvinosRESUMO
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.
Assuntos
Bacillus/isolamento & purificação , Abelhas/microbiologia , Animais , Bacillus/crescimento & desenvolvimento , Técnicas de Tipagem Bacteriana , DNA Bacteriano/análise , Mel/microbiologia , Larva/crescimento & desenvolvimento , Esporos Bacterianos/isolamento & purificaçãoRESUMO
AIMS: To compare microscopy, culture and PCR for the diagnosis of anthrax in blood samples from sheep and cattle. METHODS AND RESULTS: Blood samples were stored at room temperature and at 37 degrees C after receipt, over a period of 15-17 days. Aliquots were plated onto blood agar and blood smears were prepared. Following microscopic examination, DNA was extracted from blood smears and subjected to a multiplex PCR assay targeting the Ba813, cap and lef markers. CONCLUSIONS: PCR provided the most reliable means for the detection of Bacillus anthracis in deteriorating blood samples (15-17 days) and was also successful in diagnosing anthrax in blood smears that had been stored for 6 years and a blood sample which had been stored for 18 months at -20 degrees C. While less successful than PCR, culture for B. anthracis on 7% sheep blood agar was typically more reliable (2-17 days) than the examination of blood smears (2-6 days) for encapsulated bacilli. SIGNIFICANCE AND IMPACT OF THE STUDY: This work demonstrated the superiority of PCR for the diagnosis of anthrax from blood smear scrapings, particularly when microscopy is unreliable.
Assuntos
Antraz/veterinária , Bacillus anthracis/isolamento & purificação , Doenças dos Bovinos/diagnóstico , Reação em Cadeia da Polimerase , Doenças dos Ovinos/diagnóstico , Animais , Antraz/diagnóstico , Bacillus anthracis/citologia , Bacillus anthracis/genética , Bacillus anthracis/crescimento & desenvolvimento , Sangue/microbiologia , Bovinos , Microscopia , OvinosRESUMO
Polyclonal capture enzyme-linked immunosorbent assay (PC-ELISA), monoclonal capture ELISA (MC-ELISA), mouse neutralization test (MNT), and counterimmunoelectrophoresis (CIEP), were compared for their ability to detect epsilon toxin in intestinal contents and body fluids of sheep and goats. When used to evaluate intestinal contents of sheep artificially spiked with epsilon prototoxin, PC-ELISA detected 0.075 mouse lethal dose (MLD)50/ml, whereas the MNT, MC-ELISA, and CIEP detected 6, 25, and 50 MLD50/ml, respectively. Amounts of epsilon toxin detected by PC-ELISA, MC-ELISA, MNT, and CIEP in sheep pericardial fluid artificially spiked with epsilon prototoxin were 0.075, 0.75, 6, and 200 MLD50/ml, respectively. For assaying epsilon toxin in aqueous humor, PC-ELISA and MC-ELISA detected 0.075 MLD50/ml, whereas CIEP detected 200 MLD50/ml (MNT was not evaluated). When 51 samples of intestinal contents of sheep and goats (32 positive and 19 negative to MNT) were analyzed by the other 3 techniques, the relative sensitivity of PC-ELISA, MC-ELISA, and CIEP was 93.75, 84.37, and 37.50%, respectively. The specificity of PC-ELISA, MC-ELISA, and CIEP was 31.57, 57.89, and 84.21%, respectively. The absolute sensitivity of PC-ELISA, MC-ELISA, CIEP, and MNT was 90.90, 69.69, 15.15, and 54.54%. The absolute specificity of the 4 techniques was 100%. These results show that there is a marked inconsistency among techniques routinely used to detect Clostridium perfringens epsilon toxin. Until more consistent results are achieved, the diagnosis of enterotoxemia should not only be based solely on epsilon toxin detection, but also on clinical and pathological data.
Assuntos
Toxinas Bacterianas/isolamento & purificação , Líquidos Corporais/química , Clostridium perfringens/química , Enterotoxemia/diagnóstico , Conteúdo Gastrointestinal/química , Doenças das Cabras/diagnóstico , Doenças dos Ovinos/diagnóstico , Animais , Toxinas Bacterianas/química , Líquidos Corporais/microbiologia , Contraimunoeletroforese/veterinária , Enterotoxemia/microbiologia , Ensaio de Imunoadsorção Enzimática/veterinária , Conteúdo Gastrointestinal/microbiologia , Doenças das Cabras/microbiologia , Cabras/microbiologia , Testes de Neutralização/veterinária , Sensibilidade e Especificidade , Doenças dos Ovinos/microbiologia , Carneiro Doméstico/microbiologiaRESUMO
A comprehensive genetic analysis of 60 Mycoplasma sp. bovine group 7 isolates from different geographic origins and epidemiological settings is presented. Twenty-four isolates were recovered from the joints of calves during sporadic episodes of polyarthritis in geographically distinct regions of Queensland and New South Wales, Australia, including two clones of the type strain PG5O. A further three Australian isolates were also recovered from the tympanic bulla, retropharyngeal lymph node and the lung and another three isolates had unconfirmed histories. Six isolates originated from Germany, Portugal, Nigeria, and France. Twenty-four epidemiologically related isolates of Mycoplasma sp. bovine group 7 were recovered from multiple tissue sites and body fluids of infected calves with polyarthritis, mastitic milk, and from the stomach contents, lung and liver from aborted foetuses in three large, centrally managed dairy herds in New South Wales, Australia. Restriction endonuclease analysis (REA) of genomic DNA differentiated 29 Cfol profiles among these 60 isolates and grouped all 24 epidemiologically related isolates in a defined pattern showing a clonal origin. Three isolates of this clonal cluster were recovered from mastitic milk and the synovial exudate of clinically-affected calves and appeared sporadically for periods up to 18 months after the initial outbreak of polyarthritis indicating a persistent, close association of the organism with cattle in these herds. The Cfol profile representative of the clonal cluster was distinguishable from profiles of isolates recovered from multiple, unrelated cases of polyarthritis in Queensland and New South Wales and from other countries. All 24 isolates from the clonal cluster possessed a plasmid (pBG7AU) with a molecular size of 1022 bp. DNA sequence analysis of pBG7AU identified two open reading frames sharing 81 and 99% DNA sequence similarity with hypothetical replication control proteins A and B respectively, previously described in plasmid pADB201 isolated from M. mycoides subspecies mycoides. Other isolates of bovine group 7, epidemiologically unrelated to the clonal cluster, including two clones of the type strain PG5O, possessed a similar-sized plasmid. These data confirm that Mycoplasma sp. bovine group 7 is capable of migrating to, and multiplying within, different tissue sites within a single animal and among different animals within a herd.
Assuntos
Aborto Animal/microbiologia , Artrite/veterinária , Doenças dos Bovinos/microbiologia , Surtos de Doenças , Variação Genética , Mastite/veterinária , Mycoplasma/genética , Aborto Animal/epidemiologia , Animais , Artrite/epidemiologia , Artrite/microbiologia , Austrália/epidemiologia , Sequência de Bases , Southern Blotting/métodos , Bovinos , Doenças dos Bovinos/epidemiologia , Sondas de DNA , DNA Bacteriano , Feminino , Mastite/epidemiologia , Mastite/microbiologia , Dados de Sequência Molecular , Mycoplasma/isolamento & purificação , Plasmídeos , RNA Ribossômico 16S/análise , Mapeamento por Restrição/métodos , Análise de Sequência de RNA/métodosAssuntos
Doenças dos Bovinos/microbiologia , Infecções por Escherichia coli/veterinária , Escherichia coli/classificação , Doenças dos Ovinos/microbiologia , Toxinas Shiga/biossíntese , Animais , Austrália/epidemiologia , Bovinos , Doenças dos Bovinos/epidemiologia , Diarreia/epidemiologia , Diarreia/microbiologia , Diarreia/veterinária , Escherichia coli/isolamento & purificação , Escherichia coli/patogenicidade , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/microbiologia , Hemorragia Gastrointestinal/epidemiologia , Hemorragia Gastrointestinal/microbiologia , Hemorragia Gastrointestinal/veterinária , Sorotipagem , Ovinos , Doenças dos Ovinos/epidemiologia , VirulênciaRESUMO
The prevalence of complex Shiga toxin-producing Escherichia coli (STEC), i.e. STEC containing accessory virulence factors intimin (eaeA) and/or enterohaemorrhagic E. coli haemolysin (ehxA) and their serotypes were determined in diagnostic bovine faecal samples processed during a 3 months period. The presence of complex STEC was determined using PCR and vancomycin-cefixime-cefsulodin blood agar (BVCCA) using a dual approach which involved (i) direct culture of faecal samples on BVCCA followed by mutiplex PCR of BVCCA positive colonies and (ii) culture of faecal samples enriched in modified EC (mEC) broth (with a complex STEC profile determined by PCR) on BVCCA followed by multiplex PCR of BVCCA positive colonies. Using both techniques complex STEC were isolated from 23 (18.7%) of the 123 faecal samples. Complex STEC were isolated from 14 faecal samples by direct culture on BVCCA and 13 faecal samples yielded complex STEC by culture of mEC broths with a complex STEC profile on BVCCA. Only four samples were positive using both techniques. The serotypes isolated included O5:H-, O26:H-, O26:H11, O91:H21, O111:H-, O111:H8, O104:H11, O113:H21 and O157:H8. This study confirms that non-O157 STEC can be isolated from bovine faeces and that they carry types associated with human disease. This work also demonstrates that the use of a dual approach is advisable to increase the likelihood of isolating complex STEC.
Assuntos
Adesinas Bacterianas , Técnicas Bacteriológicas , Proteínas de Transporte , Doenças dos Bovinos/microbiologia , Diarreia/veterinária , Proteínas de Escherichia coli , Escherichia coli/isolamento & purificação , Fezes/microbiologia , Toxina Shiga I/biossíntese , Toxina Shiga II/biossíntese , Animais , Proteínas da Membrana Bacteriana Externa/análise , Proteínas da Membrana Bacteriana Externa/genética , Proteínas de Bactérias/análise , Proteínas de Bactérias/genética , Bovinos , Cefixima , Cefsulodina , Meios de Cultura , Diarreia/microbiologia , Escherichia coli/classificação , Escherichia coli/metabolismo , Escherichia coli/patogenicidade , Proteínas Hemolisinas/análise , Proteínas Hemolisinas/genética , Reação em Cadeia da Polimerase , Sorotipagem , Toxina Shiga I/análise , Toxina Shiga I/genética , Toxina Shiga II/análise , Toxina Shiga II/genética , Vancomicina , VirulênciaRESUMO
Shiga toxin 2 (Stx2) has been reported as the main Shiga toxin associated with human disease. In addition, the Stx2 toxin type can have a profound impact on the degree of tissue damage in animal models. We have characterized the stx(2) subtype of 168 Shiga toxin-producing Escherichia coli (STEC) isolates of which 146 were derived from ovine sources (principally feces and meat) and 22 were isolated from humans. The ovine STEC isolates were of serotypes that have been shown to occur commonly in the gastrointestinal tract of healthy sheep. The major stx(2) subtype in the ovine isolates was shown to be stx(2d-Ount) (119 of 146 [81.5%]) and was predominantly associated with serotypes O75:H(-)/H8/H40, O91:H(-), O123:H(-), O128:H2, and OR:H2. However, 17 of 18 (94.4%) ovine isolates of serotype O5:H(-) possessed a stx(2d-O111/OX3a) subtype. Furthermore, STEC isolates of serotypes commonly found in sheep and recovered from both clinical and nonclinical human infections also contained a stx(2d) (stx(2d-Ount/O111/OX3a)) subtype. These studies suggest that a specific stx(2) subtype(s) associates with serotype and may have important epidemiological implications for tracing sources of E. coli during outbreaks of STEC-associated diseases in humans.
Assuntos
Infecções por Escherichia coli/microbiologia , Escherichia coli/classificação , Doenças dos Ovinos/microbiologia , Toxina Shiga II/genética , Toxina Shiga II/metabolismo , Animais , Escherichia coli/metabolismo , Infecções por Escherichia coli/veterinária , Humanos , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Análise de Sequência de DNA , Sorotipagem , Ovinos , Toxina Shiga II/classificaçãoRESUMO
A group of 1,623 ovine fecal samples recovered from 65 geographically distinct mutton sheep and prime lamb properties across New South Wales, Australia, were screened for the presence of Shiga toxin-producing Escherichia coli (STEC) virulence factors (stx(1), stx(2), eaeA, and ehxA). A subset was cultured for STEC isolates containing associated virulence factors (eaeA and/or ehxA), which were isolated from 17 of 20 (85%) and 19 of 20 (95%) tested prime lamb and mutton sheep properties, respectively. STEC isolates containing stx(1), stx(2), and ehxA were most commonly isolated (19 of 40 flocks; 47.5%), and this profile was observed for 10 different serotypes. Among 90 STEC isolates studied, the most common serotypes were O91:H(-) (22 isolates [24.4%]), O5:H(-) (16 isolates [17.8%]), O128:H2 (11 isolates [12.2%]), O123:H(-) (8 isolates [8.9%]), and O85:H49 (5 isolates [5.6%]). Two isolates (2.2%) were typed as O157:H(-). A total of 78 of 90 STEC isolates (86.7%) expressed Shiga toxin in Vero cell culture and 75 of 84 ehxA-positive isolates (89.3%) expressed enterohemolysin on washed sheep blood agar. eaeA was observed in 11 of 90 (12.2%) ovine STEC isolates, including serotypes O5:H(-), O84:H(-), O85:H49, O123:H(-) O136:H40, and O157:H(-). Although only 2 of 90 isolates were typed as O157:H(-), the predominant serotypes recovered during this study have been recovered from human patients with clinical disease, albeit rarely.
Assuntos
Matadouros , Escherichia coli/classificação , Escherichia coli/patogenicidade , Ovinos/microbiologia , Toxinas Shiga/biossíntese , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , DNA Bacteriano/análise , Escherichia coli/genética , Reação em Cadeia da Polimerase/métodos , Sorotipagem , Toxinas Shiga/genética , Virulência/genéticaAssuntos
Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/microbiologia , Diarreia/veterinária , Infecções por Escherichia coli/veterinária , Escherichia coli/isolamento & purificação , Animais , Animais Recém-Nascidos , Bovinos , Diarreia/epidemiologia , Diarreia/microbiologia , Escherichia coli/genética , Escherichia coli/patogenicidade , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/microbiologia , Fezes/microbiologia , Feminino , Toxinas Shiga/genética , VirulênciaRESUMO
Twenty-five unique CfoI-generated whole-cell DNA profiles were identified in a study of 30 Paenibacillus alvei isolates cultured from honey and diseased larvae collected from honeybee (Apis mellifera) colonies in geographically diverse areas in Australia. The fingerprint patterns were highly variable and readily discernible from one another, which highlighted the potential of this method for tracing the movement of isolates in epidemiological studies. 16S rRNA gene fragments (length, 1,416 bp) for all 30 isolates were enzymatically amplified by PCR and subjected to restriction analysis with DraI, HinfI, CfoI, AluI, FokI, and RsaI. With each enzyme the restriction profiles of the 16S rRNA genes from all 30 isolates were identical (one restriction fragment length polymorphism [RFLP] was observed in the HinfI profile of the 16S rRNA gene from isolate 17), which confirmed that the isolates belonged to the same species. The restriction profiles generated by using DraI, FokI, and HinfI differentiated P. alvei from the phylogenetically closely related species Paenibacillus macerans and Paenibacillus macquariensis. Alveolysin gene fragments (length, 1, 555 bp) were enzymatically amplified from some of the P. alvei isolates (19 of 30 isolates), and RFLP were detected by using the enzymes CfoI, Sau3AI, and RsaI. Extrachromosomal DNA ranging in size from 1 to 10 kb was detected in 17 of 30 (57%) P. alvei whole-cell DNA profiles. Extensive biochemical heterogeneity was observed among the 28 P. alvei isolates examined with the API 50CHB system. All of these isolates were catalase, oxidase, and Voges-Proskauer positive and nitrate negative, and all produced acid when glycerol, esculin, and maltose were added. The isolates produced variable results for 16 of the 49 biochemical tests; negative reactions were recorded in the remaining 30 assays. The genetic and biochemical heterogeneity in P. alvei isolates may be a reflection of adaptation to the special habitats in which they originated.
Assuntos
Bacillus/classificação , Abelhas/microbiologia , Animais , Bacillus/genética , Técnicas de Tipagem Bacteriana , DNA Bacteriano/genética , DNA Ribossômico/genética , Genes Bacterianos , Proteínas Hemolisinas/genética , Compostos Orgânicos , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , RNA Ribossômico 16S/genéticaRESUMO
OBJECTIVE: To report an outbreak of mastitis, polyarthritis and abortion caused by Mycoplasma sp bovine group 7 in three large, centrally-managed dairies and to review the relevant literature. DESIGN: Epidemiological, clinical and laboratory data were analysed, collated and reported. Multidisciplinary procedures were employed. These included clinical assessment and comprehensive laboratory investigations of affected calves, aborted foetuses and milk samples. Mycoplasma cultures and genetic analyses of isolates were undertaken to identify the aetiological agent. RESULTS: About 30% of 240 calves usually kept in a calf rearing facility developed severe polyarthritis as a result of Mycoplasma sp bovine group 7 infection between 2 and 3 weeks of age. Multiple abortions occurred on these farms. Mycoplasma sp bovine group 7 was recovered from the fibrinopurulent synovial exudates of four 14-day-old calves, from the stomach contents and lungs of two aborted foetuses, from 14 of 21 bulk milk and four of 10 mastitic quarters. Three bulk colostrum samples cultured during the outbreak were negative for mycoplasma. CONCLUSION: Mycoplasma sp bovine group 7 caused significant economic losses as a result of polyarthritis, abortion and mastitis. The disease probably originated from udder infections with spread being facilitated by the decreased use of tetracycline in the treatment of mastitis. Neonatal calves were most likely infected by the consumption of milk contaminated with the organism. Abortions presumably resulted from mycoplasmaemia. This appears to be the first report in Australia of bovine abortion resulting from Mycoplasma sp infection.
Assuntos
Artrite/veterinária , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/etiologia , Surtos de Doenças/veterinária , Infecções por Mycoplasma/veterinária , Mycoplasma/isolamento & purificação , Aborto Animal/epidemiologia , Aborto Animal/etiologia , Animais , Animais Recém-Nascidos , Artrite/epidemiologia , Artrite/etiologia , Bovinos , Doenças dos Bovinos/microbiologia , Doenças dos Bovinos/patologia , Indústria de Laticínios , Feminino , Feto/microbiologia , Mastite Bovina/epidemiologia , Mastite Bovina/etiologia , Leite/microbiologia , Mycoplasma/genética , Infecções por Mycoplasma/epidemiologia , Infecções por Mycoplasma/etiologia , New South Wales/epidemiologia , Reação em Cadeia da Polimerase/veterinária , Gravidez , Líquido Sinovial/microbiologiaRESUMO
Melissococcus pluton, the causative agent of European foulbrood is an economically significant disease of honey bees (Apis mellifera) across most regions of the world and is prevalent throughout most states of Australia. 49 Isolates of M. pluton recovered from diseased colonies or honey samples in New South Wales, Queensland, South Australia, Tasmania and Victoria were compared using SDS-PAGE, Western immunoblotting and restriction endonuclease analyses. DNA profiles of all 49 geographically diverse isolates showed remarkably similar AluI profiles although four isolates (one each from Queensland, South Australia, New South Wales and Victoria) displayed minor profile variations compared to AluI patterns of all other isolates. DNA from a subset of the 49 Australian and three isolates from the United Kingdom were digested separately with the restriction endonucleases CfoI, RsaI and DraI. Restriction endonuclease fragment patterns generated using these enzymes were also similar although minor variations were noted. SDS-PAGE of whole cell proteins from 13 of the 49 isolates from different states of Australia, including the four isolates which displayed minor profile variations (AluI) produced indistinguishable patterns. Major immunoreactive proteins of approximate molecular masses of 21, 24, 28, 30, 36, 40, 44, 56, 60, 71, 79 and 95 kDa were observed in immunoblots of whole cell lysates of 22 of the 49 isolates and reacted with rabbit hyperimmune antibodies raised against M. pluton whole cells. Neither SDS-PAGE or immunoblotting was capable of distinguishing differences between geographically diverse isolates of M. pluton. Collectively these data confirm that Australian isolates of M. pluton are genetically homogeneous and that this species may be clonal. Plasmid DNA was not detected in whole cell DNA profiles of any isolate resolved using agarose gel electrophoresis.