Methicillin Resistant Staphylococcus aureus (MRSA) Isolation and mecA Gene Detection from Milk and Farmer Hand Swab in Tulungagung, Indonesia

Abstract

Dairy farms have a high incidence of MRSA infections due to the repeated use of the same medicines on dairy cows and the physical contact between farmers and cows during milking. This study evaluated the incidence of MRSA in dairy cow milk and farmer hand swabs in Tulungagung, Indonesia. Using oxacillin and cefoxitin diffusion disks, phenotypic detection approaches were evaluated, then transferred to the Oxacillin Resistance Screening Agar Base (ORSAB) test and genotypically verified using PCR to find the mecA gene encoding MRSA. One hundred ten dairy cow milk samples and 45 farmer's hand swabs were collected from Tulungagung, East Java, Indonesia. Mannitol salt agar (MSA) was used for cultivation and purification. The disk-diffusion test used oxacillin and cefoxitin to identify S. aureus resistance. Oxacillin and cefoxitin-resistant S. aureus isolates were tested for MRSA using ORSAB. In addition, MRSA isolates were PCR-tested for the mecA gene. S. aureus was found in 110 (70.97%) of 155 isolates. Of the total 110 isolates of S. aureus, 16 (14.54%) and 39 (35.45%) were known to be resistant to Cefoxitin and Oxacillin, respectively. When tested with ORSAB, 23 isolates from 55 resistant isolates showed positive results for MRSA. Dairy milk was the source of most MRSA, which is 15 isolates, while hand swabs only carried 8 isolates. However, PCR analysis only found mecA gene in two isolates. According to this study, many MRSA isolates were found in dairy farms in Tulungagung, Indonesia, but only a few have the mecA gene.

Methicillin-Resistant Staphylococcus aureus (MRSA) in Dairy Products and Bulk-Tank Milk (BTM)

“…Most MRSA infections on dairy farms are related to the continued use of antibiotics on animals and physical contact between dairy cows and milkers. Therefore, it is possible that this infection is transmitted through farmers' hands during milking [192].…”

“…The PCR method cannot be performed in all laboratories due to cost and resource limitations. To find MRSA, the limitations of PCR can be circumvented by using the disk diffusion method with cefoxitin and oxacillin, followed by investigation using ORSAB [192].…”