Diagnosis of mycobacteria in bovine milk: an overview

ABSTRACT Tuberculosis remains as the world’s biggest threat. In 2014, human tuberculosis ranked as a major infectious disease by the first time, overcoming HIV death rates. Bovine tuberculosis is a chronic disease of global distribution that affects animals and can be transmitted to humans by the consumption of raw milk, representing a serious public health concern. Despite the efforts of different countries to control and eradicate bovine tuberculosis, the high negative economic impact on meat and milk production chains remains, given the decreased production efficiency (approximately 25%), the high number of condemned carcasses, and increased animal culling rates. This scenario has motivated the establishment of official programs based on regulations and diagnostic procedures. Although Mycobacterium tuberculosis and Mycobacterium bovis are the major pathogenic species to humans and bovines, respectively, nontuberculous mycobacteria within the Mycobacterium genus have become increasingly important in recent decades due to human infections, including the ones that occur in immunocompetent people. Diagnosis of mycobacteria can be performed by microbiological culture from tissue samples (lymph nodes, lungs) and secretions (sputum, milk). In general, these pathogens demand special nutrient requirements for isolation/growth, and the use of selective and rich culture media. Indeed, within these genera, mycobacteria are classified as either fast- or slow-growth microorganisms. Regarding the latter ones, incubation times can vary from 45 to 90 days. Although microbiological culture is still considered the gold standard method for diagnosis, molecular approaches have been increasingly used. We describe here an overview of the diagnosis of Mycobacterium species in bovine milk.

Successful therapy in unusual generalized Dermatophilus congolensis infection in a calf based on modified in vitro disk diffusion test / Sucesso no tratamento de infecção generalizada em bezerra por Dermatophilus congolensis baseado em teste in vitro modificado de difusão com discos

Bovine dermatophilosis is a dermatitis characterized by typical focal or localized lesions with "paintbrush" aspect and occasionally as disseminated cutaneous disease. We report the case of a one-year-old Nelore female with history of chronic cutaneous disseminated lesions that appeared immediately after a rainfall period. Serous to purulent exudates, hair with tufted appearance, hyperkeratotic, non-pruritic, hardened, yellowish to brown, and coalescent crusty lesions were observed distributed all over its body. Removal of the crusts revealed ulcerated or hemorrhagic areas, with irregular elevated crusts like "paintbrush". Microbiological diagnosis enabled the identification of a microorganism, the Dermatophilus congolensis. Despite disseminated and chronic lesions, we obtained a successful therapy with parenteral therapy using long-acting tetracycline based on modified in vitro disk diffusion test. The present report highlights success therapy in uncommon generalized bovine dermatophilosis with selection of first-choice drugs based on modified in vitro susceptibility test, and need of responsible use of antimicrobials in livestock.(AU)

A dermatofilose bovina é uma dermatite caracterizada por lesões focais ou localizadas com aspecto de "pincel" e, ocasionalmente, como lesão cutânea disseminada. Relata-se o caso de uma fêmea bovina de um ano de idade, que foi atendida apresentando história de lesões cutâneas crônicas imediatamente após um período de alta pluviosidade. Ao exame clínico, lesões serosas a purulentas, com hiperqueratose, coalescentes, não pruriginosas, ressecadas, de coloração amarelada à acinzentada foram observadas distribuídas de modo generalizado pelo animal. A remoção das crostas revelou áreas ulceradas ou hemorrágicas, com crostas irregulares e elevadas semelhantes a "pincel". O diagnóstico microbiológico possibilitou a identificação do micro-organismo Dermatophilus congolensis. Apesar das lesões disseminadas e crônicas, a cura do animal foi obtida com tratamento parenteral usando oxitetraciclina de longa duração, baseado em teste in vitro de sensibilidade microbiana modificado. O presente relato ressalta o sucesso no tratamento de caso incomum de lesões generalizadas de dermatofilose bovina com respaldo de teste in vitro de sensibilidade modificado, bem como a necessidade do uso responsável de antimicrobianos em animais de produção.(AU)

Detecção de Brucella spp. em leite bovino não pasteurizado através da Reação de Cadeia pela Polimerase (PCR) / Detection of Brucella spp. in unpasteurized cow milk by polymerase chain reaction (PCR)

A brucelose é uma importante zoonose causada por bactérias do gênero Brucella. O homem é infectado pelo contato com as secreções reprodutivas como placenta, lóquios placentários, sêmen e secreções penianas de animais infectados ou pelo consumo de leite e derivados não pasteurizados. Com o objetivo de pesquisar a presença da bactéria no leite, foram avaliadas, através da técnica da reação em cadeia da polimerase (PCR), 30 amostras de leite cru comercializadas clandestinamente na região de Botucatu, São Paulo, bem como 50 amostras de leite entregues em laticínio, previamente à pasteurização. Das 80 amostras analisadas pela técnica de PCR, 10 (12,5%) foram positivas e 70 (87,5%) negativas. Dentre as amostras positivas, 5 amostras (16,6%) eram provenientes de comerciantes ilegais e outras 5 amostras (10%) foram obtidas no laticínio. A positividade para Brucella spp. demonstra que o patógeno se encontra presente de forma importante na região de Botucatu, São Paulo, e que o risco associado à saúde pública devido à comercialização de produtos clandestinos sem prévia pasteurização é real.(AU)

Brucellosis is a zoonosis caused by bacteria of the genus Brucella. Man infection occurs through contact with reproductive secretions as placenta and its lochia, semen and penile secretion of infected animals or by consuming unpasteurized milk and dairy products. With the objective of investigating the presence of bacteria in milk, 30 samples of raw milk sold illegally in the region of Botucatu, São Paulo, Brazil, as well as 50 samples of milk delivered to a dairy industry previously to its pasteurization were evaluated by the polymerase chain reaction (PCR) technique. Of the 80 samples analyzed, 10 samples (12.5%) were positive and 70 (87.5%) were negative. Among the positive samples, 5 (16.6%) were from illegal traders and other 5 (10%) were obtained from the dairy industry. Brucella spp. positivity shows that the pathogen is representatively present in Botucatu, São Paulo, Brazil, and the risk associated to public health due to the commercialization of illegal products without pasteurization is real.(AU)