Detection of the Gene Encoding Resistance to Ampicillin from Staphylococcus aureus Causing Subclinical Mastitis in Dairy Cows at Bandung District

An examination of 48 samples of cow's milk was conducted, taken from three farms in the Districts of Warnasari, Babakan Kiara, and Citawa in Bandung District. This study aimed to determine subclinical mastitis's causes and detect genes encoding bacterial resistance to ampicillin in these farms. Based on isolation and identification, PCR examinations, and phylogenetic tree examinations, the bacteria causing subclinical mastitis were identified as Staphylococcus aureus that genetically belongs to Staphylococcus aureus strains MVF-7 and DMB17 with genetic similarities of 84% and 65%, respectively, and Staphylococcus aureus strains SPH062R, SPH038L, and SPH029L (genetic similarity with the mecA gene of Staphylococcus aureus at 99.6%). Resistance to Staphylococcus aureus can be transmitted from livestock to farmers and the environment. The increase in antimicrobial resistance depends on the sensitivity of the compartments in humans, animals, and the environment. The level of resistance in humans is the most sensitive level when related to the parameters of the human compartment to the environment. Small-scale farmers with small livestock and land area can be a predisposing factor in increasing the spread of bacterial contamination and resistance. To stop resistance and prevent its spread, it is recommended to replace beta-lactam antibiotics such as ampicillin with other antibiotic groups that are still sensitive, such as gentamicin, oxacillin, bacitracin, and cephalosporin. Additionally, it is advised for veterinary health technicians to accurately diagnose diseases, administer correct antibiotic dosages, and select appropriate antibiotic groups that align with the cause of the disease.