Identification of bacterial agents and resistance profile of coagulase-negative staphylococci isolated from heifers submitted or not to precalving treatment

• Grant number: 16/21995-9
• Support Opportunities: Regular Research Grants - Publications - Scientific article
• Start date: February 01, 2017
• End date: July 31, 2017
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Preventive Veterinary Medicine
• Principal Investigator: Juliana Rodrigues Pozzi Arcaro
• Grantee: Juliana Rodrigues Pozzi Arcaro
• Host Institution: Instituto de Zootecnia. Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). Nova Odessa , SP, Brazil

Abstract

Identify the causative agents of mastitis present in the mammary glands of primiparousheifers submitted or not to precalving treatment and to determine the in vitroantimicrobial susceptibility profile of the CoNS isolates. Eighty-seven animals werestudied: Farm (1), 40 heifers, commercial farm, all treated precalving; Farm (2), 18heifers; Farm (3), 29 animals. On Farms 2 and 3, the animals were divided intoprecalving treated and untreated groups. The treatments consisting of intramammaryantibiotic infusion were administered 60 days before calving to all mammary quartersof each heifer after local antisepsis. Samples were collected during the precalving andcalving period, 10 days after calving, and monthly. The results showed apredominance of CoNS during the precalving (28.75%) and calving (1.25%) period onFarm 1. On Farm 2, CoNS predominated during the precalving (88.89%) and calving(60%) period in untreated heifers; in the treated group, the precalving frequency ofCoNS was 100%. On Farm 3, coagulase-positive Staphylococci (CoPS) predominatedduring the precalving and calving period in the untreated group (69.24% and 39.28%,respectively). The antibiogram revealed the following antibiotic resistance profiles:Farm 1 16.98% ampicillin, and 2.83% oxacillin; Farm 2 31.03% penicillin and 17.24% oxacillin, and Farm 3 52.22% penicillin and 13.33% oxacillin. The presence of CoNS inthe mammary gland of antibiotic-resistant heifers suggests these animals to be a source of infection in the herd. (AU)