Table 1.
Azithromycin Minimum Inhibitory Concentrations (MICs), Geometric Means, Counts, and Percentages of MIC Cut Points for All Tested Isolates at the Public Health–Seattle & King County Sexually Transmitted Disease Clinic by Year: 2012–2016
| Parameter | 2012 (n = 149)a | 2013 (n = 143)a | 2014 (n = 359) | 2015 (n = 306) | 2016 (n = 339) |
|---|---|---|---|---|---|
| AZM MIC50 | 0.25 μg/mL | 0.25 μg/mL | 0.25 μg/mL | 0.25 μg/mL | 0.25 μg/mL |
| AZM MIC90 | 0.5 μg/mL | 0.5 μg/mL | 1.0 μg/mL | 1.0 μg/mL | 1.0 μg/mL |
| Geometric mean | 0.21 μg/mL | 0.23 μg/mL | 0.30 μg/mL | 0.29 μg/mL | 0.27 μg/mL |
| MIC ≥2 μg/mL | 0 | 0 | 19 (5.3%) | 12 (3.9%) | 15 (4.4%) |
| MIC ≥1 μg/mL | 5 (3.4%) | 4 (2.8%) | 26 (7.2%) | 20 (6.5%) | 20 (5.9%) |
Abbreviations: AZM, azithromycin; MIC, minimum inhibitory concentration; MIC50, the MIC required to inhibit growth of 50% of organisms; MIC90, the MIC required to inhibit growth of 90% of organisms.
a2012 and 2013 isolates are urethral only.