Comparison of phenotypic and genotypic methods for characterization of MRSA isolated from seafood and aquatic environment

Abstract

Methicillin resistant Staphylococcus aureus is generally regarded as significant pathogen of clinical importance. Numerous methods have been developed and employed for the characterizing or subtyping of MRSA from human and animal infections. However, there are limited studies on comparison of different methods for differentiation of strains of MRSA from seafood and aquatic environment. In this study various typing methods were employed to evaluate their discriminatory power to differentiate on 65 MRSA isolated from seafood and aquatic environment by calculation of the index of discrimination.The methods employed included antibiotic resistance pattern, virulence factors profiling, accessory gene regulator typing, staphylococcal cassette chromosome mec element typing, staphylococcal protein A typing and multilocus sequence typing. The study revealed that the antibiotic resistance profiling had the highest discriminatory index of all methods, followed by virulence profiling, spa typing, MLST, SCCmec typing and agr typin. The study emphasise the use of combination of several methods for improving the efficiency of discrimination of MRSA isolates from this region. The use of combination of the typing method depends on the strain populations present in a given geographical locations and their clonality. Based on this study it can be concluded that spa or MLST in combination with the virulence or antibiotic resistances profiling produced the highest discriminatory power for typing of MRSA isolated from seafood and aquatic environment.