Volume 17, Number 4—April 2011
Dispatch
High Rates of Staphylococcus aureus USA400 Infection, Northern Canada
Table 1
Broth microdilution antimicrobial susceptibilities of select MRSA and MSSA isolates, northern Canada, 2006–2008*
Antimicrobial drug | MRSA isolates, n = 379 |
MSSA isolates, n = 286 |
p value | OR (95% CI) | |||||||
---|---|---|---|---|---|---|---|---|---|---|---|
% R | MIC range | MIC50 | MIC90 | % R | MIC range | MIC50 | MIC90 | ||||
Clindamycin | 4.2 | <0.25–>8 | <0.25 | <0.25 | 27.3 | <0.25–>8 | <0.25 | <0.25 | <0.001 | 0.12 (0.06–0.21) | |
Erythromycin | 5.5 | <0.25–>8 | 1 | 2 | 28.0 | 0.5–>8 | 2 | >8 | <0.001 | 0.15 (0.09–0.26) | |
Vancomycin | 0 | <0.25–2 | 1 | 1 | 0 | 0.5–2 | 1 | 1 | NS | – | |
SXT | 0 | <0.25–2 | <0.25 | <0.25 | 0 | <0.25–2 | <0.25 | <0.25 | NS | – | |
Tetracycline | 0.3 | <2–>16 | <2 | <2 | 0 | <2 | <2 | <2 | NS | – | |
Ciprofloxacin | 2.4 | <0.12–>8 | 0.5 | 0.5 | 1.7 | 0.25–>8 | 0.5 | 0.5 | NS | – | |
Rifampin | 0 | <0.25 | <0.25 | <0.25 | 0 | <0.25 | <0.25 | <0.25 | NS | – | |
Fusidic acid | 2.1 | <0.06–>8 | 0.12 | 0.25 | 7.7 | <0.06–>8 | 0.25 | 0.5 | 0.001 | 0.26 (0.1–0.62) | |
Linezolid | 0 | 0.5–4 | 2 | 4 | 0 | 1–4 | 4 | 4 | NS | – | |
Gentamicin | 1.6 | <0.5–>16 | <0.5 | <0.5 | 8.0 | <0.5–>16 | <0.5 | 1 | <0.001 | 0.18 (0.07–0.48) | |
Mupirocin | 86.5 | <0.12–>128 | >128 | >128 | 26.9 | <0.12–>128 | 0.5 | >128 | <0.001 | 17.46 (11.56–26.43) | |
Synercid | 0 | <0.25–0.5 | <0.25 | 0.5 | 0 | <0.25–1 | 0.5 | 0.5 | NS | – | |
Nitrofurantoin | 0 | <32 | <32 | <32 | 0 | <32 | <32 | <32 | NS | – |
*Values are mg/mL except as indicated. MRSA, methicilllin-resistant Staphylococcus aureus; MSSA, methicillin-susceptible S. aureus; R, resistant; OR, odds ratio; CI, confidence interval; MIC50, 50% minimum inhibitory concentration; MIC90, 90% inhibitory concentration; SXT, sulfamethoxazole/trimethoprim; NS, not significant.
1Members of the Northern Antibiotic Resistance Partnership are listed at the end of this article.