Comparison of Neisseria gonorrhoeae Antimicrobial Susceptibility among Urogenital Isolates Obtained from Women, Men Who Have Sex with Women, and Men Who Have Sex with Men
The emergence of cephalosporin-resistant Neisseria gonorrhoeae threatens the effectiveness of the only remaining recommended treatment regimen. The United States (US) surveillance system for gonococcal antimicrobial susceptibility monitors susceptibility trends exclusively among men with symptomatic urethral infection, the population from whom the yield of gonococcal culture is highest. Little is known about the susceptibility of female urogenital isolates, and it is unclear whether gonococcal susceptibility among men who have sex exclusively with women (MSW) is representative of gonococcal susceptibility among women.
We performed a secondary analysis of gonorrhea treatment trial data to compare susceptibility of urogenital gonococcal isolates obtained from women, MSW, and men who have sex with men (MSM). Pre-treatment isolates were collected from trial participants in five US cities during 2010–2012; minimum inhibitory concentrations (MICs) were determined by agar dilution at CDC. Geometric mean MICs were adjusted for geographic location using general linear models.
Susceptibility data for urogenital isolates from 56 women, 252 MSW, and 170 MSM were available and included in the analysis. The adjusted geometric mean ceftriaxone MIC was similar among women (0.007 µg/ml, 95% CI 0.005–0.009 µg/ml) and MSW (0.006 µg/ml, 95% CI 0.005–0.007 µg/ml). In contrast, the adjusted geometric mean ceftriaxone MIC was significantly higher among MSM (0.010 µg/ml, 95% CI 0.008–0.012 µg/ml) than MSW. This same pattern was observed for other antimicrobials, including cefixime (women: 0.016 µg/ml, 95% CI 0.011–0.024 µg/ml; MSW: 0.017 µg/ml, 95% CI 0.016–0.019 µg/ml; MSM: 0.023 µg/ml, 95% CI 0.020–0.028 µg/ml) and azithromycin (women: 0.157 µg/ml, 95% CI 0.108–0.228 µg/ml; MSW: 0.174 µg/ml, 95% CI 0.155–0.195 µg/ml; MSM: 0.280 µg/ml, 95% CI 0.241–0.325 µg/ml).
As previously observed, ceftriaxone, cefixime, and azithromycin MICs were significantly higher among MSM than MSW. MICs were similar among women and MSW. These findings suggest that gonococcal antimicrobial susceptibility surveillance based on urethral isolates from MSW may adequately represent susceptibility of urogenital N. gonorrhoeae in women.
R. D. Kirkcaldy, None
S. S. Philip, None
H. C. Wiesenfeld, None
J. R. Papp, None
P. R. Kerndt, None
L. Venkatasubramanian, None
K. G. Ghanem, None
E. W. Hook III, None