Performance of CHROM Agar and Oxacillin Resistant Screening Agar Base Media for Detection of Methicillin Resistant Staphylococcus aureus (MRSA) from Chronic Wound

Abstract

CHROM agar Staphylococcus aureus and Oxacillin Resistant Screening Agar Base (ORSAB) media with oxacillin were evaluated for the screening of Methicillin Resistant Saphylococcus aureus (MRSA). Among 190 samples, totally 126 confirmed Staphylococcus aureus strains were used for screening of MRSA used CHROM agar and ORSAB media were compared with the other MRSA screening media like Baird Park agar (BPA) with ciprofloxacin, Mannitol salt agar (MSA) with oxacillin, Blood agar (BA) with oxacillin and Muller Hinton agar (MHA) with oxacillin. Totally 54 MRSA strains were confirmed using PCR, among that 83% and 92% of the MRSA stains were isolated as mauve colonies on CHROM agar and blue colonies on ORSAB medium in 24 hrs incubation, compare with 64%, 61%, 50%, and 42% of the strains that were isolated on BPA, MSA, BA and MHA respectively. After 48 hrs of incubation 100%, 98%, 77%, 77%, 72% and 68% of the MRSA strains were isolated on CHROM agar, ORSAB, BPA, MSA, BA and MHA respectively. CHROM agar Staphylococcus aureus and ORSAB agar proved to be more sensitivity and specificity than other MRSA selective media. These provide an alternative for the detection of MRSA in clinical laboratories, especially when PCR is unavailable.

Identification and Characterisation of Methicillin-Resistant Staphylococcus aureus Isolated from Bovine Mastitis

“…Thus, CHROM agar was found superior to the oxacillin screen agar method. Similar findings were also observed by Taguchi et al, (2004) and Karthy et al, (2009). This provides an alternative for the detection of MRSA in clinical laboratories, especially when PCR is unavailable.…”

Phenotypic and Genotypic Identification of Methicillin-Resistant Coagulase Negative Staphylococcus spp. Isolated from Bovine Mastitis

“…CHROMagar was found superior to the oxacillin screen agar methods for phenotypic detection of methicillin resistant isolates. Similar findings were also observed by Taguchi et al, (2004) and Karthy et al, (2009). Higher sensitivity of CHROM agar in this study might be attributed to the fact that CHROMagar with cefoxitin supplement was potent inducer of the mecA gene; this could explain why heterogeneous MRS populations that variably express the mecA gene are better detected by CHROMagar with cefoxitin than medium with oxacillin, which is a weak inductor of PBP2a production.…”

Methicillin Resistant Staphylococcus aureus (MRSA): A Review

“…Both has advantages and disadvantages such as speed, reliability and acessibility. Phenotypic methods involves standard microbiological technique of S. aureus detection which include Gram staining, colonial morphorlogy, catalase and coagulase tests, pigment production and anaerobic growth (Karthy et al, 2009). Additional methods include Minimum Inhibitory Concentrations, methods that detect mecA gene or PBP2 0 protein and media containing oxacillin (Louie et al, 2001).…”