GENETIC HOMOGENEITY AMONG METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUSSTRAINS FROM SAUDI-ARABIA

Ninety-four strains of methicillin-resistant Staphylococcus aureus (MR SA) were collected from patients nursed in several hospitals in Saudi Arabia, before they were referred to King Faisal Specialist Hospital a nd Research Centre for tertiary care. The hospitals were from geograph ically diverse regions and as such the entirety of Saudi Arabia was co vered. All strains were genetically typed by random amplification of p olymorphic DNA (RAPD) analysis using three different primers and a rep resentative subset of the strains was analyzed with pulsed-field gel e lectrophoresis (PFGE) as well. It was concluded that 87 out of 94 (93% ) belong to a single clonally related lineage of MRSA, In the other 7 cases, the DNA banding patterns were shown to differ only slightly fro m those determined for the clonal type, PFGE analysis confirmed the ho mogeneity of the collection of strains. When the RAPD and PFGE fingerp rints obtained for the Saudi clone mere compared to those generated fo r a collection of MRSA with a more diverse geographical background, it was shown that the clonal type from Saudi Arabia was not identical to any of these MRSA strains. Our data provide another example of the ca pacity of certain MRSA clones to expand through entire nations and est ablish themselves permanently among large number of hospitals and, con sequently, even larger numbers of patients.