A comparative assessment of ribosomal DNA polymorphisms in methicillin resistant Staphylococcus aureus (MRSA) epidemiology

Abstract

Chromosomal DNA from 19 strains of methicillin resistant Staphylococcus aureus (MRSA) which included 13 strains from different geographical locations in England and 6 strains from St George's Hospital (SGH), London, with MRSA NCTC 119040 and Oxford S. aureus were digested with the restriction endonucleases, HindIII and HaeIII. Southern blot hybridisation was carried out on the DNA digests transferred onto membrane using radioactive probe prepared from 16S and 23S rRNA from Escherichia coli. The pattern of bands which depended on restriction fragment length polymorphisms was used as a measure of minor genomic variation within the MRSA strains. Phage typing, biotyping, antibiogram, and plasmid profile analysis were also carried out on all the strains for comparison. Four and five different patterns were obtained for HindIII and HaeIII, respectively for representative isolates from different geographical locations in England for that year. Three different patterns were identified among the MRSA strains from SGH, London, using HaeIII. None of the epidemiological markers used in this study gave results that correlated with each other. Ribosomal DNA polymorphisms have proved to be a very useful technique for studying the epidemiology of MRSA in hospitals when used along with other epidemiological markers.

Antimicrobial Resistance Patterns and Plasmid Profiles of Methicillin Resistant Staphylococcus aureus Isolated from Clinical Samples

“…Plasmid profile analysis appears to be of very low discriminatory capacity in the investigation of MRSA epidemiology because of the non-detection of plasmids in the majority of the MRSA strains. This has been reported by Terry et al [29] and Ugbugo et al [30]. All plasmid-carrying strains harbored a single plasmid.…”

Distribution of genes encoding aminoglycoside modifying enzymes amongst methicillin resistant and methicillin sensitive Staphylococcus aureus isolates from Nigerian hospitals

“…aureus suspension was lysed to release DNA from a centrifuged deposit of 5 ml overnight Mueller Hinton broth culture of the organism in 0.5 ml of TES (Tris HCl pH 8.0, 1 mM EDTA and 0.1 M NaCl) containing lysostaphin (1 mg/ml) (Sigma, UK) incubated at 37°C for 15 min. After which the DNA was extracted with phenolchloroform, purified and precipitated with ethanol as previously described (Alli et al, 2007). PCR for the mecA gene was carried out on all the strains as previously described (Murakami and Minamide, 1993).…”