Characterisation of methicillin resistant Staphylococcus aureus strains isolated in a tertiary care hospital in the United Arab Emirates

Abstract number: 1733_1067

Sonnevend A., Pal T., Ungvari E., Paszti J., Jumaa P., al-Dhaheri K.

Objectives: The incidence of methicillin resistant Staphylococcus aureus (MRSA) is generally perceived to be low in the United Arab Emirates (UAE) compared to that of most western countries where its high prevalence is due, to a large extent, to the spread of epidemic MRSA (E-MRSA) clones. Our main aim was to type the local MRSA isolates and to compare them to the worldwide known E-MRSA strains. We investigated 50 MRSA strains isolated from individual patients between July 2002 and July 2003 at a tertiary care referral hospital, Tawam Hospital, Al Ain, UAE.

Methods: The presence of the mecA gene, and those coding for enterotoxin A-E, toxic shock syndrome toxin and exfoliativ toxin A and B were investigated by PCR. Furthermore, the antibiotic sensitivity and phage type of the isolates and the macro-restriction profile subsequent to SmaI digestion of the genom were also determined.

Results: All isolates harboured the mecA gene, 54% of them possessed at least one of the toxin genes. None of the strains exhibited reduced susceptibility to vancomycin, while resistance to other antibiotics varied. Surprisingly, as pheno-, and genotyping revealed, 26% of the isolates (13 strains) were identical or nearly identical to E-MRSA15, and 12% (6 strains) showed more than 80% similarity by PFGE to the USA100 clone, i.e. the most widespread MRSA clones in the United Kingdom and the United States, respectively.

Conclusion: The lack of detailed epidemiological data prevented us to determine the origin of these MRSA strains. However, patients receiving medical care outside of the UAE may serve as potential sources, although the extent of local spread remains to be investigated. The possibility of carrying E-MRSA strains either by patients or by healthcare workers between continents and countries calls for a well co-coordinated effort of authorities to limit the further spread of this pathogen.