No abstract

Background: Staphylococcus aureus is gram-positive cocci, which causes multiple complications such as bone, skin, joint and soft tissue infections. Penicillin was the first antibiotic that showed resistance to S. aureus; however, following penicillin, S. aureus became resistant to Methicillin and became a problem in many parts of the world. Worldwide epidemiology of S. aureus varies by country. In Austria, CA-MRSA accounts for 10% of all MRSA isolates. Many clones of S. aureus were discovered in Asian and as well as in European countries. Many patients in Southeast Asia are infected with various S. aureus variants. Aim: The aim of this study was to review epidemiology and antibiotic resistance of S. aureus in different countries. Results: Previous findings revealed that Panton-Valentine leukeocidin (PVL) genes were present in S. aureus strains. Furthermore, most widely accepted antibiotic resistance genes in clinical isolates of S. aureus strains are mecA. S. aureus spread throughout the hospital and into the community as well. They differ from one another in some ways, such as PVL genes and staphylococcal Chromosomal Cassette Mec (SCCmec) subtyping. Conclusion: It is concluded based on previously published research as well as review articles that different clones are of S. aureus are present in different regions of the world which further shows similar characteristics in some regions while totally different from the clones found in other countries. S. aureus infection can be treated by combining some antibiotics such as Vancomycin with Rifampin and Gentamicin. It can also be avoided by practicing good hand hygiene and avoiding intravenous drugs, which can cause a variety of infections. Keywords: Staphylococcus aureus, MRSA, CA-MRSA, HA-MRSA, Resistance

Staphylococcus epidermidis (S. epidermidis) is a common pathogen in ocular infection. Mutations contribute to drug resistance. We intended to identify mutations in genes within the quinolone resistance determining region (QRDR) of fluoroquinolone-resistant S. epidermidis ocular isolates and to study their phenotypic and genotypic correlation. A total of 50 phenotypically fluoroquinolones-resistant S. epidermidis isolates were studied. Fluoroquinolones susceptibility was evaluated by Kirby-Bauer disk diffusion method. Polymerase chain reaction (PCR) was optimized and applied followed by DNA sequencing to detect mutations in gyrA, gyrB, parC and parE in the QRDR region among the fluoroquinolone-resistant S. epidermidis isolates recovered from ocular specimens. The majority of the samples (74%) were from conjunctival swabs (n = 37). gyrA, gyrB, parC, and parE genes were detected in 47 samples (94%). gyrA gene (n = 47) was the most common, followed by parE (n = 35), gyrB (n = 30) and parC (n = 28). In 25 isolates, all four mutated genes were present. In 25(50%) S. epidermidis isolates mutations were observed in all four genes of QRDR region of S. epidermidis genome. This is the first study in a tertiary eye care hospital in India to characterise ocular S. epidermidis for fluoroquinolone resistance which showed mutations were predominant in gyrA gene in the QRDR region compared to 3 other genes.