Variation in the genomic location and copy number of the
insertion element 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 examined. A PCR amplicon of the insertion element was used
to probe genomic
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 element but could not be subtyped by profiling it. EMRSA-16
did not contain
IS1181, consistent with a unique evolutionary origin
for this major UK epidemic strain.
Marked heterogeneity was observed among isolates of EMRSA-03. Each EMRSA-03
strain
examined gave a unique pattern, thereby allowing subtyping of an important
epidemic phage
type for the purposes of hospital cross-infection control.