TABLE 1.
Numbers of pvl-positive MRSA and MSSA isolates identified each year between 2002 and 2011 by the Irish National MRSA Reference Laboratory
| yr | MRSA isolates |
MSSA isolates |
||||
|---|---|---|---|---|---|---|
| No. identified by NMRSARL | No. investigated for pvla | No. (%) confirmed pvl positiveb | No. identified by NMRSARL | No. investigated for pvla | No. (%) confirmed pvl positiveb | |
| 2002 | 497 | 8 | 1 (0.2)c | 1 | 1 | 1 (100) |
| 2003 | 599 | 17 | 4 (0.7)c | 0 | 0 | 0 (0) |
| 2004 | 724 | 134 | 10 (1.4)c | 15 | 14 | 3 (20) |
| 2005 | 827 | 112 | 9 (1.1)c | 43 | 30 | 5 (11.6) |
| 2006 | 869 | 110 | 12 (1.4) | 41 | 31 | 5 (12.2) |
| 2007 | 782 | 120 | 17 (2.2) | 42 | 29 | 6 (14.3) |
| 2008 | 747 | 179 | 37 (5.0) | 58 | 53 | 7 (12.1) |
| 2009 | 605 | 187 | 32 (5.3)d | 44 | 35 | 5 (11.4) |
| 2010 | 596 | 160 | 28 (4.7)d | 77 | 61 | 5 (6.5) |
| 2011 | 456 | 190 | 40 (8.8)d | 81 | 61 | 2 (2.5) |
| Total | 6,702 | 1,217 | 190 (2.8) | 401 | 315 | 39 (9.7) |
An isolate was selected for pvl investigation if it was from a suspected pvl-associated infection or, for MRSA only, if the isolate exhibited an antibiogram-resistogram (AR) and pulsed-field group (PFG) pattern distinct from that of previously or currently predominant pvl-negative health care-associated MRSA clones, e.g., AR-PFG 06-01, indicative of ST22-MRSA-IV, or AR-PFG 13/14-00, indicative of ST8-MRSA-IIA-E ± SCCM1.
The values shown in parentheses indicate the percentages of pvl-positive MRSA or MSSA isolates identified among the total number of MRSA or MSSA isolates investigated by the NMRSARL each year during the study period.
The MRSA isolates recovered between 2002 and 2005 were described previously (30). One MRSA isolate (E1760) from that study was excluded because pvl was not detected, despite several attempts using PCR and DNA microarray profiling.
One, eight, and nine pvl-positive isolates recovered in 2009, 2010, and 2011, respectively, were described previously (31).