Geraldo Márcio da Costa

Freqüência de enteroparasitas em amostras de alface (Lactuca sativa) comercializadas em Lavras, Minas Gerais

The aim of this study was to evaluate the parasitological contamination in samples of lettuce (Lactuca sativa) commercialized in Lavras city, Minas Gerais. The samples of lettuce showed low hygienic conditions, indicated by the presence of parasites of animal or human origin and high concentration of fecal coliforms.

Mastite por leveduras em bovinos leiteiros do Sul do Estado de Minas Gerais, Brasil

The objective of this study was to report the frequency of intramammary infections by yeasts, in Minas Gerais State, from milk samples (n = 1710) collected in 40 dairy herds. Fifty six yeast strains of the genus Candida and one strain of Trichosporon loubieri were isolated. Candida albicans was the dominant species (28.1% of the strains), followed by Candida parapsilosis (19.3%), Candida catenulata (14.0%), Candida glabrata (14.0%), Candida tropicalis (8.8%). Mixed infections were detected in 29.8% of yeast-positive cows. The yeast infection was more frequent (84%) in cows with subclinical mastitis. The low rate of isolation of yeasts suggests that these microorganisms are not relevant to bovine mastitis in the studied region.

Molecular epidemiology of Streptococcus agalactiae isolated from mastitis in Brazilian dairy herds

Streptococcus agalactiae is one of the most common pathogens leading to mastitis in dairy herds worldwide; consequently, the pathogen causes major economic losses for affected farmers. In this study, multilocus sequence typing (MLST), genotypic capsular typing by multiplex polymerase chain reaction (PCR), and virulence gene detection were performed to address the molecular epidemiology of 59 bovine (mastitis) S. agalactiae isolates from 36 dairy farms located in the largest milk-producing mesoregions in Brazil (Minas Gerais, São Paulo, Paraná, and Pernambuco). We screened for the virulence genes bac, bca, bibA, cfb, hylB, fbsA, fbsB, PI-1, PI-2a, and PI-2b, which are associated with adhesion, invasion, tissue damage, and/or immune evasion. Furthermore, five capsular types were identified (Ia, Ib, II, III, and IV), and a few isolates were classified as non-typeable (NT). MLST revealed the following eight sequence types (STs): ST-61, ST-67, ST-103, ST-146, ST-226, ST-314, and ST-570, which were clustered in five clonal complexes (CC64, CC67, CC103, CC17, and CC314), and one singleton, ST-91. Among the virulence genes screened in this study, PI-2b, fbsB, cfb, and hylB appear to be the most important during mastitis development in cattle. Collectively, these results establish the molecular epidemiology of S. agalactiae isolated from cows in Brazilian herds. We believe that the data presented here provide a foundation for future research aimed at developing and implementing new preventative and treatment options for mastitis caused by S. agalactiae.

Botulismo em bovinos leiteiros no Sul de Minas Gerais, Brasil

An outbreak of bovine botulism in a dairy herd caused by ingestion of contaminated maize, in southern Minas Gerais, Brazil is described. The herd was composed by 148 lactating cows of high milk production fed with diet based on maize ensilage and concentrate in a free stall system. Thirty eight cows were affected, with 100% of fatality rate. Samples from intestine, rumen and liver of necropsied cattle and drinking water and maize were submitted to the mouse bioassay and soroneutralization tests for detection of Clostridium botulinum toxins. Types C and D toxins were detected in samples from intestinal and rumen contents and maize. The reporter of an outbreak of botulism in cattle associated with an unusual source of toxin, shows that stocked maize in inadequate conditions is a factor of risk for the occurrence of the botulism in dairy cattle.

Influência do descarte involuntário de matrizes no impacto econômico da mastite em rebanhos leiteiros

Objetivou-se com esta pesquisa, analisar e quantificar a influencia do descarte involuntario de matrizes no impacto economico da mastite em rebanhos leiteiros. A pesquisa foi realizada por meio de simulacao no sistema computacional CU

Resistência a antimicrobianos em Staphylococcus aureus isolados de mastite em bovinos leiteiros de Minas Gerais, Brasil

TO MASTITE, considerando rebanhos leiteiros com taxas de descarte de 2, 4 e 6%. Foram considerados como prevencao as despesas com monitoramento (cultura e antibiograma, contagem de celulas somaticas no tanque e contagem de celulas somaticas individuais), pre e pos dipping, vacinacao, tratamento de vacas secas e manutencao de ordenhadeira. Como medidas curativas consideraram-se os tratamentos de casos clinicos, cuja percentagem foi de 7% das vacas em lactacao. O impacto da mastite foi estimado como sendo o total de perdas acrescido das despesas com prevencao e tratamento de casos clinicos. O aumento da taxa de descarte influenciou diretamente no impacto economico da mastite. O elevado impacto economico evidencia a necessidade de monitoramento da doenca, para diminuirem os prejuizos causados pela mesma. As despesas com tratamento preventivo representaram, no maximo, 9,2% do impacto economico, o que demonstra vantagem em investir nessa pratica, pois ela ira contribuir significativamente para diminuicao da contagem de celulas somaticas no tanque e, consequentemente, para reduzir o impacto economico da mastite.

Virulence Genes of the Streptococcus agalactiae Associated with BovineMastitis in Minas Gerais Livestock Herds, Brazil

Staphylococcus aureus (S. aureus) stands out as one of the most common etiological agents of bovine mastitis, currently causing major economic losses to dairy farming. In order to evaluate the sensitivity of this micro-organism to antimicrobials, 352 isolates from 35 dairy herds located in the state of Minas Gerais were submitted to antibiogram tests, using the disc diffusion technique. Nitrofurantoin and the associations of neomycin, bacitracin and tetracycline (NBT), as well as penicillin, nafcillin and dihydrostreptomycin (PND), showed 100% efficiency in vitro. There were low resistance rates in the group of cephalosporins, with values of 0, 0.28 and 0.40% for cefquimona, cephalothin, and ceftiofur, respectively. Among the aminoglycosides, there was 1.69% resistance to gentamicin and 3.35% for neomycin. The highest resistance was observed for polymyxin B (82%), followed by betalactams, ampicillin and penicillin, with resistance rates of 80.92 and 80.45%, respectively. Moderate levels of resistance were observed for tetracycline, lincomycin, cefoperazone and sulfazotrim. Among the tested isolates, 65 (18.15%), coming from 24 of the 35 herds studied, showed multidrug resistance (MAR index ≥ 0.2). The results pointed out to high variation in antimicrobial resistance profiles and the occurrence of multidrug resistance among some studied strains, highlighting the importance of antibiogram tests for the choice of an appropriate drug to be used for the treatment or prevention of mastitis caused by

Uso de PCR Duplex para detecção dos genes femA e mecA e determinação da concentração inibitória mínima (CIM) em Staphylococcus aureus isolados de leite cru

Brazil has the second largest dairy herd in the world. Minas Gerais is the largest milk producer in Brazil and accounts for about 30% of all production in the country. The mastitis is a disease that causes major losses in the dairy industry under the economic point of view, because maintains a high prevalence and limited response to therapy and may be caused by more than one hundred different etiologic agents mainly bacteria. It is estimated that the loss in milk production by untreated, reach between 12 and 15%. Whatever its origin, there are chemical and physical changes in the milk, accompanied by pathological changes in the glandular tissue. Streptococcus agalactiae is highly contagious and ubiquitous in the mammary gland, is a major etiological agents of mastitis. The elucidation of the virulence factors of this agent is of great importance for the prevention and treatment of mastitis. Because of the few published studies with S. agalactiae isolates from cattle, this study aims to compare isolates from clinical and subclinical mastitis in relation to the presence of virulence genes related to polysaccharide capsule rich in sialic acid, hyaluronate lyase, fibrinogen binding protein and pili. Primers were designed to amplify the genes fbsA, cpsC, cpsD, cpsE, cpsK, neuB and the PI-1 cluster of 16 isolates of Streptococcus agalactiae from clinical mastitis and subclinical mastitis. Molecular analysis showed the presence of gene fbsA in 85.07% of the isolates, 38.80% in hylB, cpsC, cpsD and cpsE at 4.48%, cpkJ, cpsK and neuB 79.10% in the cluster and PI-1 at 1.49%. Observed diversity of strains within and between different flocks, however, no relationship was observed among virulence factors evaluated and the severity of infection.

Seleção, caracterização e clonagem dos genes fljB e groEL agonistas dos receptores de reconhecimento de padrão do sistema imune inato das aves

This study identified Staphylococcus aureus and the methicillin-resistant (MRSA) strains in raw milk samples using molecular methods, and their minimum inhibitory concentrations (MIC) were evaluated. Two hundred fifty-one samples of raw milk samples from bulk tanks, collected in the state of Minas Gerais, Brazil were analyzed using polymerase chain reaction (PCR) to investigate the presence of femA gene in 278 S.aureus isolates. Furthermore, MRSA strains were investigated for detecting mecA gene. All of 278 isolates contained the femA gene (132 bp), and in 11 samples (3.95 %) the mecA gene (533 bp) was identified. The minimum inhibitory concentration against S. aureus was determined using enrofloxacin, trimethoprim-sulfamethoxazole, gentamicin, azithromycin, tetracycline, cephalothin, amoxicillin, penicillin G and lincomycin. Enrofloxacin and trimethoprim-sulfamethoxazole showed to be the most effective inhibitors, as this study identified 149 of 161 isolates (92.5 % of susceptibility) with MIC≤ 4 mg/ mL, and 55 of 66 isolates (83.3 % of susceptibility) with MIC≤ 2 mg/mL, for the first antimicrobial drug and the second one, respectively.

Viabilidade de Tritrichomonas foetus após congelamento com diferentes crioprotetores

A producao recombinante de agonistas dos receptores do reconhecimento de padrao do sistema imune inato tem fornecido uma nova ferramenta para a producao de imunoestimulantes para animais. O padrao molecular associado ao patogeno (PAMP), flagelina, codificado pelo gene fljB de Salmonella Typhimurium e o padrao molecular associado ao dano (DAMP) HSP60, codificado pelo gene groEL da S. Typhimurium e S. Enteritidis, sao reconhecidos por receptores de reconhecimento de padroes (RRPs) do sistema imune inato das aves. No presente estudo, foi feita a clonagem de fragmentos geneticos dos genes fljB de S. Typhimurium e groEL de S. Typhimurium e S. Enteritidis inseridos no vetor de expressao pET100/D-TOPO e transformados em celulas de E. coli TOP10. Os clones foram avaliados pela PCR de colonia, PCR de DNA plasmidial e sequenciamento genomico para a confirmacao da presenca desses genes. Na PCR de colonia, foram identificadas em 80%, 60% e 80% das colonias transformadas, a presenca dos genes groEL (S. Enteritidis), groEL (S. Typhimurium) e fljB (S. Typhimurium) respectivamente. O sistema de clonagem adotado possibilitou a producao de clones dos fragmentos geneticos da HSP60 e flagelina das cepas de Salmonella, permitindo a utilizacao posterior desses clones em ensaios de expressao genica, com potencial futuro de serem utilizados como imunoestimulante inespecifico das aves.