Comparison Of Susceptibility Test Methods For Determining Oxacillin Resistance In Clinical Isolates

Asian Journal of Pharmaceutical and Health Sciences,2011,1,1,26-29.
Published:February 2011
Type:Research Article

To compare conventional phenotypic methods for the detection of methicillin in Staphylococci aureus in routine laboratory practice with reference to an established molecular method. This study was conducted on a selection of 30 isolates of methicillin resistant Staphylococci aureus (MRSA) from clinical specimens. The Kirby- Bauer disc diffusion tests and oxacillin screen ager method were performed on all isolates using the presence of penicillin binding protein (PBP2a) as the reference standard. A commercial latex agglutination test (Oxoid, UK) was assessed for the detection of penicillin binding protein 2a (PBP2a), the Mec A gene product. Twenty of 30 isolates were positive to PBP2a and concomitant manifest resistance to (oxacillin) was confirmed using Kirby-Bauer diffusion test. All the thirty isolates were resistant using disk diffusion method. The specificity and sensitivity of this method, in comparison with PBP2a was 100% in our examined strains, whereas the specificity and sensitivity for oxacillin agar screen was 80% and 73.3% respectively. The specificity of routine laboratory tests for MRSA detection was variable mec A gene detection, the "gold standard" to confirm ambiguous results is difficult to perform in routine diagnostic laboratories. The Oxoid kit for the detection of PBP2a is an alternative that could be used in most laboratories

Susceptibility Test Methods use in the Study