ABSTRACT Although the tuberculin test represents the main in vivo diagnostic method used in the control and eradication of bovine tuberculosis, few studies have focused on the identification of mycobacteria in the milk from cows positive to the tuberculin test. The aim of this study was to identify Mycobacterium species in milk samples from cows positive to the comparative intradermal test. Milk samples from 142 cows positive to the comparative intradermal test carried out in 4,766 animals were aseptically collected, cultivated on Lowenstein-Jensen and Stonebrink media and incubated for up to 90 days. Colonies compatible with mycobacteria were stained by Ziehl-Neelsen to detect acid-fast bacilli, while to confirm the Mycobacterium genus, conventional PCR was performed. Fourteen mycobacterial strains were isolated from 12 cows (8.4%). The hsp65 gene sequencing identified M. engbaekii (n=5), M. arupense (n=4), M. nonchromogenicum (n=3), and M. heraklionense (n=2) species belong to the Mycobacterium terrae complex. Despite the absence of M. tuberculosis complex species in the milk samples, identification of these mycobacteria highlights the risk of pathogen transmission from bovines to humans throughout milk or dairy products, since many of mycobacterial species described here have been reported in pulmonary and extrapulmonary diseases both in immunocompetent and immunocompromised people.

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.

Relata-se caso incomum de osteomielite mandibular deformante em vaca, causada por Trueperella (Arcanobacterium) pyogenes, na face ventro-lateral da porção caudal do ramo direito da mandíbula. A punção aspirativa de fragmento da lesão permitiu a caracterização citológica, o isolamento microbiano e identificação de T. pyogenes. Exame radiográfico mostrou acentuada reação periodontal na mandíbula direita, com predomínio de áreas líticas e destruição da cortical óssea. Apesar da instituição do tratamento baseado no teste de sensibilidade microbiana in vitro, foi recomendada a eutanásia, em virtude da piora progressiva do estado geral do animal. No exame post-mortem foram observados múltiplos abscessos na lesão que, histologicamente, foi caracterizada como piogranuloma. A colheita de material da região mandibular afetada, após a necropsia, resultou no reisolamento microbiológico de T. pyogenes

This study reports an unusual case of deforming mandibular osteomyelitis in a cow caused by Trueperella (Arcanobacterium) pyogenes, on the face of the ventrolateral caudal portion of the right branch of the mandible. Fragment aspired of lesion by fine needle allowed cytological characterization, isolation and identification of T. pyogenes. Radiographic examination showed marked periosteal reaction in the right mandible, numerous lytic areas and cortical bone destruction. Despite of treatment based on in vitro antimicrobial sensitivity test, it was recommended the euthanasia due to progressive worsening of the cow's condition. Multiple abscesses were observed in the mandibular region at necropsy. Pyogranuloma was characterized in histological exam. Sampled material collected from the lesion after necropsy resulted in microbiological reisolation of T. pyogenes