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BioMed Research International
Volume 2015, Article ID 615153, 9 pages
http://dx.doi.org/10.1155/2015/615153
Research Article

Molecular Detection and Sensitivity to Antibiotics and Bacteriocins of Pathogens Isolated from Bovine Mastitis in Family Dairy Herds of Central Mexico

1Food Department, Life Sciences Division, University of Guanajuato, Campus Irapuato-Salamanca, 36500 Irapuato, GTO, Mexico
2Graduate Program in Biosciences, Life Sciences Division, University of Guanajuato, Campus Irapuato-Salamanca, 36500 Irapuato, GTO, Mexico
3Agronomy Department, Life Sciences Division, University of Guanajuato, Campus Irapuato-Salamanca, 36500 Irapuato, GTO, Mexico
4Department of Physics, University of Antwerp, Campus Groenenborger, Groenenborgerlaan 171, 2020 Antwerp, Belgium
5Experimental Immunology Laboratory, National Institute of Pediatrics, Ministry of Health, 04530 México, DF, Mexico

Received 6 August 2014; Revised 11 November 2014; Accepted 9 December 2014

Academic Editor: Joel E. López-Meza

Copyright © 2015 Ma. Fabiola León-Galván et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Thirty-two farms ( cows) located in the state of Guanajuato, Mexico, were sampled. Pathogens from bovine subclinical mastitis (SCM) and clinical mastitis (CLM) were identified by 16S rDNA and the sensitivity to both antibiotics and bacteriocins of Bacillus thuringiensis was tested. Forty-six milk samples were selected for their positive California Mastitis Test (CMT) (≥3) and any abnormality in the udder or milk. The frequency of SCM and CLM was 39.1% and 9.3%, respectively. Averages for test day milk yield (MY), lactation number (LN), herd size (HS), and number of days in milk (DM) were 20.6 kg, 2.8 lactations, 16.7 animals, and 164.1 days, respectively. MY was dependent on dairy herd (DH), LN, HS, and DM , and correlations between udder quarters from the CMT were around 0.49 . Coagulase-negative staphylococci were mainly identified, as well as Staphylococcus aureus, Streptococcus uberis, Brevibacterium stationis, B. conglomeratum, and Staphylococcus agnetis. Bacterial isolates were resistant to penicillin, clindamycin, ampicillin, and cefotaxime. Bacteriocins synthesized by Bacillus thuringiensis inhibited the growth of multiantibiotic resistance bacteria such as S. agnetis, S. equorum, Streptococcus uberis, Brevibacterium stationis, and Brachybacterium conglomeratum, but they were not active against S. sciuri, a microorganism that showed an 84% resistance to antibiotics tested in this study.