title: Molecular detection and sensitivity to antibiotics and bacteriocins of pathogens isolated from bovine mastitis in family dairy herds of central Mexico.
abstract: Thirty-two farms (n = 535 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 (P < 0.01), and correlations between udder quarters from the CMT were around 0.49 (P < 0.01). 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.
authors: Food Department, Life Sciences Division, University of Guanajuato, Campus Irapuato-Salamanca, 36500 Irapuato, GTO, Mexico ; Graduate Program in Biosciences, Life Sciences Division, University of Guanajuato, Campus Irapuato-Salamanca, 36500 Irapuato, GTO, Mexico.
authors: Ma Fabiola
authors: MF
authors: León-Galván
authors: Food Department, Life Sciences Division, University of Guanajuato, Campus Irapuato-Salamanca, 36500 Irapuato, GTO, Mexico ; Graduate Program in Biosciences, Life Sciences Division, University of Guanajuato, Campus Irapuato-Salamanca, 36500 Irapuato, GTO, Mexico.
authors: José E
authors: JE
authors: Barboza-Corona
authors: Agronomy Department, Life Sciences Division, University of Guanajuato, Campus Irapuato-Salamanca, 36500 Irapuato, GTO, Mexico.
authors: A Arianna
authors: AA
authors: Lechuga-Arana
authors: Graduate Program in Biosciences, Life Sciences Division, University of Guanajuato, Campus Irapuato-Salamanca, 36500 Irapuato, GTO, Mexico ; Agronomy Department, Life Sciences Division, University of Guanajuato, Campus Irapuato-Salamanca, 36500 Irapuato, GTO, Mexico.
authors: Mauricio
authors: M
authors: Valencia-Posadas
authors: Department of Physics, University of Antwerp, Campus Groenenborger, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
authors: Daniel D
authors: DD
authors: Aguayo
authors: Experimental Immunology Laboratory, National Institute of Pediatrics, Ministry of Health, 04530 México, DF, Mexico.
authors: Carlos
authors: C
authors: Cedillo-Pelaez
authors: Agronomy Department, Life Sciences Division, University of Guanajuato, Campus Irapuato-Salamanca, 36500 Irapuato, GTO, Mexico.
authors: Erika A
authors: EA
authors: Martínez-Ortega
authors: Graduate Program in Biosciences, Life Sciences Division, University of Guanajuato, Campus Irapuato-Salamanca, 36500 Irapuato, GTO, Mexico ; Agronomy Department, Life Sciences Division, University of Guanajuato, Campus Irapuato-Salamanca, 36500 Irapuato, GTO, Mexico.
authors: Abner J
authors: AJ
authors: Gutierrez-Chavez
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D001430:Bacteriocins / Q000008:administration & dosage; D002417:Cattle; D003612:Dairying; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005260:Female; D006801:Humans; D008414:Mastitis, Bovine / Q000188:drug therapy / Q000382:microbiology*; D008800:Mexico; D008826:Microbial Sensitivity Tests; D008892:Milk / Q000382:microbiology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D013211:Staphylococcus aureus / Q000187:drug effects / Q000472:pathogenicity
chemical_list: D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D012336:RNA, Ribosomal, 16S