TABLE 2.
Comparison* of Antimicrobial Susceptibility Distribution by Antimicrobial and Anatomic Site of Gonococcal Infection Among Men Who Have Sex With Men: eGISP and SURRG, 2018 to 2019
| Antimicrobial and Measured Parameter† | Pharyngeal (n = 1049) | Rectal (n = 1553) | Urethral (n = 3974) |
|---|---|---|---|
| Azithromycin | |||
| MIC range, μg/mL | 0.008–16 | 0.008–16 | 0.008–16 |
| Geometric mean MIC (95% CI) | 0.32 (0.30–0.34) | 0.31 (0.29–0.33) | 0.30 (0.29–0.31) |
| No. (%) [95% CI] with elevated MIC | 124/1049 (11.2) [9.4–13.3] | 182/1553 (11.3) [9.8–13.1] | 420/3974 (10.2) [9.3–11.3] |
| Cefixime | |||
| MIC range, μg/mL | 0.002–0.5 | 0.002–1 | 0.002–0.25 |
| Geometric mean MIC (95% CI) | 0.0192 (0.0185–0.020) | 0.0181 (0.0175–0.0187) | 0.0176 (0.0173–0.018) |
| No. (%) [95% CI] with elevated MIC | 3/1049 (0.29) [0.09–0.88] | 8/1553 (0.52) [0.26–1.0] | 11/3974 (0.28) [0.15–0.50] |
| Ceftriaxone | |||
| MIC range, μg/mL | 0.001–0.125 | 0.001–0.5 | 0.001–0.125 |
| Geometric mean MIC (95% CI) | 0.0108 (0.0103–0.0113) | 0.00987 (0.0095–0.0102) | 0.0098 (0.0096–0.0101) |
| No. (%) [95% CI] with elevated MIC | 7/1049 (0.67) [0.32–1.4] | 2/1553 (0.13) [0.03–0.51] | 7/3974 (0.18) [0.08–0.37] |
| Ciprofloxacin | |||
| MIC range, μg/mL | 0.001–32 | 0.001–32 | 0.001–32 |
| Geometric mean MIC (95% CI) | 0.12 (0.10–0.15) | 0.11 (0.09–0.13) | 0.12 (0.10–0.13) |
| No. (%) [95% CI] with resistant MIC | 450/1049 (42.7) [39.5–46.0] | 649/1553 (41.6) [38.9–44.2] | 1701/3974 (42.6) [40.9–44.3] |
| Penicillin | |||
| MIC range, μg/mL | 0.008–64 | 0.008–64 | 0.008–64 |
| Geometric mean MIC (95% CI) | 0.63 (0.58–0.68) | 0.60 (0.57–0.65) | 0.66 (0.63–0.69) |
| No. (%) [95% CI] with resistant MIC | 140/1049 (13.0) [11.0–15.2] | 200/1553 (12.6) [11.0–14.4] | 603/3974 (14.8) [13.7–16.0] |
| Tetracycline | |||
| MIC range, μg/mL | 0.06–64 | 0.06–64 | 0.06–64 |
| Geometric mean MIC (95% CI) | 1.55 (1.44–1.68) | 1.48 (1.39–1.58) | 1.47 (1.40–1.53) |
| No. (%) [95% CI] with resistant MIC | 377/1049 (35.7) [32.7–38.8] | 512/1553 (32.9) [30.5–35.4] | 1377/3974 (34.5) [32.9–36.1] |
We fitted overall models with and without “anatomic sites” and compared the 2 models to get the overall P value; if the overall P value was statistically significant (<0.05), we conducted post hoc testing to adjust for multiple tests using the Holm adjustment. Linear mixed-effects model was used for geometric mean MICs, and mixed-effects logistic regression model was used for the proportion of isolates with elevated or resistant MICs across anatomic sites, respectively, to account for the multiple isolates provided by the same patients. All geometric mean MICs were not statistically significant (P < 0.05) except for cefixime and ceftriaxone; all proportions with elevated or resistant MICs were not statistically significant except for ceftriaxone.
The Clinical and Laboratory Standards Institute has not established the criteria for resistance to azithromycin, cefixime, and ceftriaxone; breakpoints used to define “elevated MIC” for these antimicrobials include the following: azithromycin MIC of ≥2.0 μg/mL, cefixime MIC of ≥0.25 μg/mL, and ceftriaxone MIC of ≥0.125 μg/mL. Antimicrobial susceptibility testing results were interpreted according to the criteria recommended by the Clinical and Laboratory Standards Institute for penicillin resistance (MIC ≥2 μg/mL or β-lactamase positive), ciprofloxacin resistance (MIC ≥1.0 μg/mL), and tetracycline resistance (MIC ≥2.0 μg/mL). Tested ranges for antimicrobials (μg/mL): azithromycin (0.008–16), cefixime (0.002–1), ceftriaxone (0.001–1), ciprofloxacin (0.001–32), penicillin (0.008–64), tetracycline (0.06–64).
CI, confidence interval; eGISP, enhanced Gonococcal Isolate Surveillance Project; MIC, minimum inhibitory concentration; SURRG, Strengthening the US Response to Resistant Gonorrhea.