Presencia de bacterias de los géneros Staphylococcus aureus, Escherichia coli y Brucella abortus y su perfil de resistencia antimicrobiana en leche cruda bovina procedente de Tunshi y San Andres.

Abstract

A microbiological analysis and antibiotic resistance of bacteria isolated from raw milk of bovine expended in the dairy Company "La Herencia" in San Andrés and the dairy company "Santa Fe" in Tunshi was performed. The collection and transport of samples evaluated in each one of the samples was conducted in accordance with the provisions of the Standard NTE INEN 0004 standard. The microbiological indicators which were analyzed to determine the hygienic-sanitary quality were, Escherichia coli, Staphylococcus aureus, Brucella by Petrifilm plates 3M, in the case of Escherichia coli and Staphylococcus aureus, and agar culture Farrell in the case of Brucella, verifying the existence of bacteria through confirmatory tests as the test of oxidase, seed in agar methylene blue and Gram staining kit MicrogenTM GN-ID identification. The count of Escherichia coli, exceeded the limits allowed under the Technical Regulations RTCR: 401-2006 in 100% (6/6), since the values obtained in counts range of 3000 CFU / mL to 102,333.3 CFU / mL and the standard amount maximum allowable for this bacteria is 100 CFU / mL. Staphylococcus aureus count turned out to be higher than the reference value (maximum 500 CFU / mL) ranging from 23,333 CFU / mL and 58,666 CFU / mL. Confirmatory tests such as coagulase, mannitol salt agar, Gram staining and Kit MicrogenTM GN-ID identification, coincided with the growth of Staphylococcus Petrifilm plates. For Brucella was no growth (0/9) in the modified agar brain - heart with selective supplement for the isolation of Brucella. The profile of antimicrobial resistance in bacteria identified was performed by the agar diffusion method according to Kirby Bauer. Escherichia coli showed resistance to ampicillin, in the same manner 33.3% (01/03) was the Tetracycline and a 33.3% (01/03) to the respectively streptomycin, 100% of Escherichia coli were sensitive to kanamycin and gentamicin and nitrofurantoin. Staphylococcus aureus were resistant only to penicillin and 100% of them showed sensitivity to ciprofloxacin, clindamycin, amikacin, tetracycline, erythromycin and cefoxitin. It was concluded that the bacteriological quality of raw milk marketed is defective, and the microorganisms showed higher resistance to antibiotics as: ampicillin, streptomycin, tetracycline and penicillin. It is recommended to the Ministry of Health and agencies perform to have a permanent training and control with technical and trained personnel to protect public health and to have quality products.