Vol. 12, Special Issue 8 (2023)

Author(s):
Someswari U, Sreedevi B, Vinod Kumar N and Jagadeesh Babu A

Abstract:
Methicillin-resistant Staphylococcus aureus (MRSA) is a major global public health problem and swine have become reservoir of S. aureus, including MRSA. To determine prevalence of MRSA in swine, isolation of MRSA was carried out from 55 nasal swab samples of healthy piglets and a total of 57 Staphylococcus spp. were isolated, of which 43 (75.44%) isolates were S. aureus and 14 (24.56%) were Non-aureus Staphylococcus spp. The susceptibility profiles to antibiotics were tested by phenotypic and genotypic techniques. Antimicrobial susceptibility was determined against seven antimicrobial agents. As cefoxitin serves as a substitute for mec A-mediated methicillin/oxacillin resistance, a cefoxitin disc (30 g) screening test was used to detect phenotypic methicillin resistance. High frequency of resistance was recorded for chloramphenicol (87.72%) followed by cefoxitin (85.96%), tetracycline (36.84%), novobiocin (22.81%), ciprofloxacin (22.81%) and oxacillin (8.8%). All the isolates were found susceptible to gentamycin. 49 (85.96%) isolates including 40 S. aureus and nine Non-aureus Staphylococcus spp, shown cefoxitin resistance, indicating that they were methicillin resistant phenotypically. Genotypic methicillin resistance was detected by screening DNA of all the recovered isolates for mecA and mec C genes by using PCR technique. Of 57 isolates tested, mecA gene has been found in 11 isolates (19.29%) of Staphylococci. Out of these 11 isolates, six were methicillin resistant S. aureus (MRSA) and five were methicillin resistant Non-aureus Staphylococcus (MRNaS) isolates. The relative frequency of mecA gene in MRSA and MRNaS was 13.95% and 35.71% respectively. None of the isolates carried mecC gene.