Although nmMRSA strains appear to have originated in the community, they may include nmEMRSA strains that have been associated with healthcare facilities (e.g., EMRSA-15, EMRSA-16, and the New York/Japan EMRSA) or nonmultidrug-resistant sporadic hospital MRSA strains that have been taken into the community.
Twenty-nine clones were identified, including 7 (22.5%) EMRSA clones and 22 (77.5%) CA-MRSA clones.
Table 1 shows the 7 EMRSA clones identified: ST22-MRSA-IV (EMRSA-15), ST239-MRSA-III (Aus-2 and Aus-3 EMRSA), ST8-MRSA-[IV.sub.pediatric] (Irish-2 EMRSA), ST36-MRSA-II (EMRSA-16), ST5-MRSA-II (New York/Japan EMRSA), ST8-MRSA-[II.sub.variant] (Irish-1 EMRSA), and the classic MRSA clone ST250-MRSA-I.
Overall, 94.6% of EMRSA were identified either as ST22-MRSA-IV (78.1%), a urease-negative nmEMRSA clone (resistant to erythromycin and ciprofloxacin) or ST239-MRSA-III (16.5%).
Although part of this increase in the metropolitan area from 1998 was due to an increase in EMRSA notifications, most can be attributed to CAMRSA (unpub.
A statewide screening and control policy was implemented in WA after an outbreak of EMRSA in a Perth hospital in 1982 (16).
From 1983 to 1997, MRSA was categorized as EMRSA or WAMRSA according to antimicrobial drug resistance patterns based on previous genetic analysis (14).
Figure 2 shows notifications of WAMRSA and EMRSA in WA from 1983 to 2002.
In 1998, 6.4% of MRSA notifications were classified as EMRSA, increasing to 24.4% in 2002.
This time span has afforded a unique opportunity to document 2 important occurrences, 1) preventing EMRSA from becoming established in the hospital system and 2) emerging community-associated MRSA throughout WA.