Volume 18, Number 1—January 2012
Dispatch
MRSA USA300 at Alaska Native Medical Center, Anchorage, Alaska, USA, 2000–2006
, Karen M. Rudolph, Thomas W. Hennessy, Diana L. Zychowski, Karthik Asthi, Susan Boyle-Vavra, and Robert S. Daum
Table 2
MRSA isolate characteristics, combined retrospective and prospective collection samples by region of patient residence, Alaska, USA, 2000–2006*†
| CC and ST | No. (%) patients |
||
|---|---|---|---|
| Anchorage region, n = 97 | Southwestern region, n = 56 | Other regions, n = 71 | |
| CC1‡ | |||
| ST1 | 25 (26) | 43 (77) | 10 (14) |
| CC5 | |||
| ST5 | 11 (11) | 2 (4) | 16 (23) |
| ST105 | 1 (1) | 2 (4) | 9 (13) |
| ST225 | 0 | 0 | 1 (1) |
| ST231 | 0 | 1 (2) | 1 (1) |
| CC8§ | |||
| ST8 | 32 (33) | 2 (4) | 9 (13) |
| CC30 | |||
| ST30 | 14 (14) | 3 (5) | 16 (23) |
| ST30slv | 3 (3) | 2 (4) | 0 |
| CC45 | |||
| ST45 | 1 (1) | 0 | 0 |
| ST45slv | 1 (1) | 0 | 0 |
| ST54 | 1 (1) | 0 | 0 |
| CC59 | |||
| ST59 | 7 (7) | 1 (2) | 7 (10) |
| ST969 | 0 | 0 | 2 (3) |
| ST969slv | 1 (1) | 0 | 0 |
| SCCmec type | |||
| II | 10 (10) | 4 (7) | 29 (41) |
| IV | 88 (91) | 52 (93) | 39 (55) |
| c-2.5 | 1 (1) | 0 | 3 (4) |
*MRSA, methicillin-resistant Staphyloccus aureus; CC, clonal complex; ST, sequence type; slv, single locus variant; SCCmec, staphylococcal cassette chromosome mec; PFGE, pulsed-field gel electrophoresis.
†Among 61 isolates genotyped from the prospective cohort, 18 were from inpatients (ST1 [n = 9], ST105 [n = 1], ST231 [n = 1], ST5 [n = 3], and ST8 [n = 4]), and 43 were from outpatients (ST1 [n = 14], ST105 [n = 1], ST30 [n = 2], ST30slv [n = 1], ST5 [n = 3], and ST8 [n = 22]).
‡CC1 has recently been changed to CC15 by the administrators of the multilocus sequence typing system. A randomly selected sample of 14 ST1 isolates that carried the SCCmec type IV element and were Panton-Valentine leukocidin positive underwent PFGE, and 93% (13/14) were USA400.
§42/43 ST8 strains identified in the study carried the SCCmec type IV element and were Panton-Valentine leukocidin positive. They are all considered to be USA300 because 30 of the 42 were randomly selected to undergo PFGE, and 100% (30/30) had the USA300 pulsotype.