ANALYSIS OF METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS BY IS1181 PROFILING

Variation in the genomic location and copy number of the insertion ele ment IS1181 in methicillin-resistant Staphylococcus aureus (MRSA) was investigated. Sixty-three isolates representing the Jevons type strain (NCTC 10442), phage-propagating strains, and epidemic strains were ex amined. A PCR amplicon of the insertion element was used to probe geno mic restriction endonuclease digests. HindIII genomic digests gave 25 distinct IS1181 patterns, while EcoRI digests gave 20 patterns. EMRSA- 01, -02, -04, -06, -07, -09, -10, -11, -13 and -14 contained the eleme nt but could not be subtyped by profiling it. EMRSA-16 did not contain IS1181, consistent with a unique evolutionary origin for this major U K epidemic strain. Marked heterogeneity was observed among isolates of EMRSA-03. Each EMRSA-03 strain examined gave a unique pattern, thereb y allowing subtyping of an important epidemic phage type for the purpo ses of hospital cross-infection control.