RESUMO

Brucellosis is a zoonotic disease that causes important economic losses in Brazil, and the country has therefore established a national program for its control and eradication. Using data generated in the last national brucellosis survey, we conducted an economic analysis in two Brazilian States with different brucellosis status, Mato Grosso (with high prevalence) and Sao Paulo (with low prevalence). The economic analysis was based on the calculation of the additional benefits and costs of controlling bovine brucellosis through the vaccination of heifers aged between 3 and 8 months with S19 vaccine, considering maximal and minimal impacts of the disease. The analysis showed that vaccinating 90% of the replacement heifers aged 3-8 months of age offers the best economic performance in a vaccination program against bovine brucellosis if compared to vaccination rates of 70% and 80%. Moreover, regions with higher prevalences of bovine brucellosis would experience significant economic advantages when implementing a vaccination strategy to control the disease. This economic analysis will allow decision makers to plan more economically effective vaccination programs.

Assuntos

RESUMO

This study aimed to evaluate the efficiency of stretching in the reduction of pathogens when compared to milk pasteurization, the official method to ensure safe cheese production. Whole buffalo milk was contaminated with Mycobacterium fortuitum, Listeria monocytogenes, Salmonella typhimurium, and Staphylococcus aureus. Part of the milk was used in mozzarella production and the other part was submitted to holder pasteurization. Pathogens were quantified before and after thermal processing (mozzarella stretching and milk pasteurization). Pasteurization and stretching led to the following reductions in log cycles, respectively: 4.0 and 6.3 for Mycobacterium sp.; 6.0 and 8.4 for Listeria sp.; >6.8 and 4.5 for Staphylococcus sp.; and >8.2 and 7.5 for Salmonella sp.

Este estudo teve como objetivo avaliar a eficácia da filagem na redução de patógenos,em comparação coma pasteurizaçãodo leite, que é o método oficialpara garantir aprodução de queijos seguros. Leite de búfala integral foi contaminado com Mycobacterium fortuitum, Listeria monocytogenes, Salmonella typhimurium e Staphylococcus aureus. Parte desse leite foi empregada na fabricação da mozarela e outra parte foi submetida à pasteurização lenta. Os patógenosforam quantificadosantes e após os processos térmicos (filagem da mozarela e pasteurização do leite). As reduções, em ciclos logarítmicos, causadas pela pasteurização e pela filagem, respectivamente, foram: 4,0 e 6,3 de Mycobacterium sp., 6,0 e 8,4 de Listeria sp., >6,8 e 4,5 de Staphylococcus sp. e >8,2 e 7,5 de Salmonella sp.

Assuntos

RESUMO

This study compared 4 protocols for DNA extraction from homogenates of 6 different organs of cows infected with the Brucella abortus 2308 strain. The extraction protocols compared were as follows: GT (guanidine isothiocyanate lysis), Boom (GT lysis with the carrying suspension diatomaceous earth), PK (proteinase K lysis), and Santos (lysis by boiling and freezing with liquid nitrogen). Positive and negative gold standard reference groups were generated by classical bacteriological methods. All samples were processed with the 4 DNA extraction protocols and amplified with the B4 and B5 primers. The number of positive samples in the placental cotyledons was higher than that in the other organs. The cumulated results showed that the Santos protocol was more sensitive than the Boom (p=0.003) and GT (p=0.0506) methods and was similar to the PK method (p=0.2969). All of the DNA extraction protocols resulted in false-negative results for PCR. In conclusion, despite the disadvantages of classical bacteriological methods, the best approach for direct diagnosis of B. abortus in organs of infected cows includes the isolation associated with PCR of DNA extracted from the cotyledon by the Santos or PK methods.

Assuntos

RESUMO

Between 2007 and 2009, a cross-sectional survey was carried out in Maranhão State, Brazil to estimate the seroprevalence of and risk factors for bovine brucellosis. In total, 749 herds and 6779 cows greater than two years of age were blood sampled. At the time of sampling a questionnaire to collect details on possible risk factors for bovine brucellosis was administered to the participating herd manager. A logistic regression model was developed to quantify the association between herd demographic and management characteristics and the herd-level brucellosis status. Spatial analyses were carried out to identify areas of the state where the presence of brucellosis was unaccounted-for by the explanatory variables in the logistic regression model. The estimated herd-level prevalence of brucellosis in Maranhão was 11.4% (95% CI 9.2-14) and the individual animal-level prevalence was 2.5% (95% CI 1.7-3.6). Herds with more than 54 cows older than two years of age, herds that used rented pasture to feed cattle, and the presence of wetlands on the home farm increased the risk of a herd being brucellosis positive. Infected farms were identified throughout the state, particularly in the central region and on the northwestern border. Spatial analyses of the Pearson residuals from the logistic regression model identified an area in the center of the state where brucellosis risk was not well explained by the predictors included in the final logistic regression model. Targeted investigations should be carried out in this area to determine more precisely the reasons for the unexplained disease excess. This process might uncover previously unrecognized risk factors for brucellosis in Maranhão.

Assuntos

RESUMO

This study aimed to evaluate the efficiency of stretching in the reduction of pathogens when compared to milk pasteurization, the official method to ensure safe cheese production. Whole buffalo milk was contaminated with Mycobacterium fortuitum, Listeria monocytogenes, Salmonella typhimurium, and Staphylococcus aureus. Part of the milk was used in mozzarella production and the other part was submitted to holder pasteurization. Pathogens were quantified before and after thermal processing (mozzarella stretching and milk pasteurization). Pasteurization and stretching led to the following reductions in log cycles, respectively: 4.0 and 6.3 for Mycobacterium sp.; 6.0 and 8.4 for Listeria sp.; >6.8 and 4.5 for Staphylococcus sp.; and >8.2 and 7.5 for Salmonella sp.(AU)

Este estudo teve como objetivo avaliar a eficácia da filagem na redução de patógenos,em comparação coma pasteurizaçãodo leite, que é o método oficialpara garantir aprodução de queijos seguros. Leite de búfala integral foi contaminado com Mycobacterium fortuitum, Listeria monocytogenes, Salmonella typhimurium e Staphylococcus aureus. Parte desse leite foi empregada na fabricação da mozarela e outra parte foi submetida à pasteurização lenta. Os patógenosforam quantificadosantes e após os processos térmicos (filagem da mozarela e pasteurização do leite). As reduções, em ciclos logarítmicos, causadas pela pasteurização e pela filagem, respectivamente, foram: 4,0 e 6,3 de Mycobacterium sp., 6,0 e 8,4 de Listeria sp., >6,8 e 4,5 de Staphylococcus sp. e >8,2 e 7,5 de Salmonella sp.(AU)

Assuntos

RESUMO

A fervura do leite foi avaliada quanto à inativação de Staphylococcus aureus (ATCC 25923), Salmonella Typhimurium (ATCC 14028) e Mycobacterium fortuitum (NCTC 8573) inoculados em leite integral de vaca, cabra e búfala. As amostras de leite, previamente tratadas, foram contaminadas com os patógenos. Três repetições foram realizadas com cada tipo de leite. As amostras foram analisadas antes e depois da fervura e também após 24h sob refrigeração. As amostras foram diluídas em série e a metodologia oficial foi usada para quantificar Staphylococcus aureus, e adaptada para se obter o NMP de Salmonella. O número de UFC de Mycobacterium foi obtido em meio Löwenstein-Jensen, incubados a 37°C/5 dias. Antes da fervura, as amostras tinham entre 6,8 e 8,0 log UFC ou NMP/mL, de cada agente. Após a fervura, Staphylococcus foi recuperado em uma das 3 amostras de leite de vaca (1x10 UFC/mL), e Salmonella em todas as três amostras de leite de búfala (0,3 NMP/mL cada). Mycobacterium não foi detectado em nenhuma das analises realizadas após a fervura. As amostras fervidas e refrigeradas mostraram ausência de crescimento de todos os agentes. Nas condições estudadas, os resultados comprovam a efetividade da fervura do leite em reduzir o risco microbiológico a níveis mínimos.

The inactivation of Staphylococcus aureus (ATCC 25923), Salmonella Typhimurium (ATCC 14028) and Mycobacterium fortuitum (NCTC 8573) inoculated in cow, goat and buffalo whole milk submitted to the boiling was evaluated. Milk samples, previously treated, were contaminated with the pathogens and boiled. Tree replicates were performed with each kind of milk. Samples were analyzed immediately before and after the boiling, and also after 24h under refrigeration. Samples were serial diluted and official method was used to quantify Staphylococcus aureus, and it was adapted to get the MPN of Salmonella. The number of CFU of Mycobacterium was obtained on Löwenstein-Jensen medium, incubated to 37°C/5 days. Before boiling the milk samples had from 6.8 to 8.0 log CFU or MPN/mL, of each agent. After boiling, Staphylococcus was recovery in one of three cow milk samples (1x10 CFU/mL), and Salmonella in all three buffalo milk samples (0.3 MPN/mL each). Mycobacterium was not detected in any of analysis made after the boiling. Boiled and refrigerated samples showed no growth in all of them. Under the studied conditions, the results prove the effectiveness of domestic boiling to reduce biological risk to minimum levels.

Assuntos

RESUMO

The inactivation of Staphylococcus aureus (ATCC 25923), Salmonella Typhimurium (ATCC 14028) and Mycobacterium fortuitum (NCTC 8573) inoculated in cow, goat and buffalo whole milk submitted to the boiling was evaluated. Milk samples, previously treated, were contaminated with the pathogens and boiled. Tree replicates were performed with each kind of milk. Samples were analyzed immediately before and after the boiling, and also after 24h under refrigeration. Samples were serial diluted and official method was used to quantify Staphylococcus aureus, and it was adapted to get the MPN of Salmonella. The number of CFU of Mycobacterium was obtained on Löwenstein-Jensen medium, incubated to 37°C/5 days. Before boiling the milk samples had from 6.8 to 8.0 log CFU or MPN/mL, of each agent. After boiling, Staphylococcus was recovery in one of three cow milk samples (1x10 CFU/mL), and Salmonella in all three buffalo milk samples (0.3 MPN/mL each). Mycobacterium was not detected in any of analysis made after the boiling. Boiled and refrigerated samples showed no growth in all of them. Under the studied conditions, the results prove the effectiveness of domestic boiling to reduce biological risk to minimum levels.

A fervura do leite foi avaliada quanto à inativação do Staphylococcus aureus (ATCC 25923), Salmonella Typhimurium (ATCC 14028) e Mycobacterium fortuitum (NCTC 8573) inoculados em leite integral de vaca, cabra e búfala. As amostras de leite, previamente tratadas, foram contaminadas com os patógenos. Três repetições foram realizadas com cada tipo de leite. As amostras foram analisadas antes e depois da fervura e também após 24h sob refrigeração. As amostras foram diluídas em série e a metodologia oficial foi usada para quantificar Staphylococcus aureus, e adaptada para se obter o NMP de Salmonella. O número de UFC de Mycobacterium foi obtido em meio Löwenstein-Jensen, incubados a 37°C/5 dias. Antes da fervura, as amostras tinham entre 6,8 e 8,0 log UFC ou NMP/mL, de cada agente. Após a fervura, Staphylococcus foi recuperado em uma das 3 amostras de leite de vaca (1x10 UFC/mL), e Salmonella em todas as três amostras de leite de búfala (0,3 NMP/mL cada). Mycobacterium não foi detectado em nenhuma das analises realizadas após a fervura. As amostras fervidas e refrigeradas mostraram ausência de crescimento de todos os agentes. Nas condições estudadas, os resultados comprovam a efetividade da fervura do leite em reduzir o risco microbiológico a níveis mínimos. PALAVRAS-CHAVE: Microbiologia. Mycobacterium fortuitum. Salmonella Typhimurium. Staphylococcus aureus. Tratamento térmico.