Identificação de Staphyloccus aureus, avaliação do seu pontecial enterotoxigênico e resistência a meticilina pela técnica de PCR em amostras de leite da microrregião de Sete Lagoas - MG, 2009

• Ano de defesa: 2010
• Autor(a) principal: Natanael Lamas Dias
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: MRSA; enterotoxinas; Staphylococcus aureus; PCR; Veterinária; Leite Análise; Estafilococos aureos; Reação em cadeia de polimerase
• Link de acesso: http://hdl.handle.net/1843/SSLA-87QN2J

The identification of Staphylococcus aureus in milk and the evaluation of its potential enterotoxic were evaluable during period from march to june of 2009, on the milk samples from cattle farms located in the microregion of Sete Lagoas-MG. A protocol for DNA extraction from S. aureus directly from milk samples, followed by amplifications by PCR of the genes fem A, sea, seb and sec were used. The Methicillin resistant Staphylococcus aureus (MRSA) were detected by amplification of the mec A gene. The sensitivity and specificity of the technique was tested in milk artificially contaminated milk using a decimal dilution of S. aureus standard strains (ATCC 25923, ATCC 13565, ATCC 14458, ATCC 19095 and ATCC 33591). The detection limit of microorganisms was 10 CFU / mL for all genes evaluated with specific primers. The specificity was determined by the presence of expected PCR products from the DNA of the reference strains (positive control) and not amplified DNA from S. epidermidis (negative control). 200 milk samples from the expansion tank from the microregion of Sete Lagoas-MG were available for the presence of the gene fem A. The results were analyzed statistically if there was a relationship between the presence of S. aureus identified in milk samples with higher Total bacteria cont (CBT) and the largest somatic cell cont (CCS) were also related to increased presence of S. aureus. Of the 200 samples, 145 (72.5%) amplified the gene fem A, and were analyzed for the presence of genes sea, seb, sec and mec A. The genes of enterotoxins most prevalent were: sea (60%), followed by seb (37.93%) and then sec (6.89%). There were found 18 milk samples (11.03%) with S. aureus carriers of the gene mec A, identifying the presence of MRSA. There was no correlation between the rates of identification of S. aureus and high CCS or CBT. The detection of S. aureus directly from milk, without the need for bacterial isolation, and characterization of its enterotoxic potential suggests the use of this PCR technique for epidemiological studies of staphylococcal infections. In addition, the S. aureus is one of the major causative pathogen of intramammary infections in the microregion of Sete Lagoas-MG and have a high potential enterotoxic. It is represents a potential risk to public health. It should be noted that the presence of MRSA highlights the selection of antibiotics resistant microorganisms, suggesting that the indiscriminate use of antibiotics in addition to compromising the quality of milk and milk products is a risk to human health