The emergence of Neisseria gonorrhoeae with decreased susceptibility to azithromycin in Kansas City, Missouri, 1999 to 2000

Background and Objectives: We describe the first cluster of persons with Neisseria gonorrhoeae with decreased susceptibility to azithromycin (AziDS; minimum inhibitory concentration greater than or equal to1.0 mug/mL) in the United States. Goal: The goal of this study was to identify risk factors for AziDS N. gonorrhoeae and to describe isolate microbiology. Study Design: Persons with AziDS N. gonorrhoeae (cases) were identified in Kansas City, Missouri, through the Gonococcal Isolate Surveillance Project (GISP) in 1999 and expanded surveillance, January 2000 to June 2001. A case-control study using 1999 GISP participants was conducted; control subjects had azithromycin-susceptible N. gonorrhoeae. Results: Thirty-three persons with AziDS N. gonorrhoeae were identified. Case patients were older than control patients (median age, 33 years vs. 23 years; P <0.001). Fifty percent of cases and 13% of control subjects had a history of sex with a female commercial sex worker (odds ratio, 7.0; 95% confidence interval, 1.3-36.0); 50% of cases and 4% of control subjects met sex partners on street A (P <0.01). AziDS N. gonorrhoeae isolates were phenotypically and genotypically similar and contained an mtrR gene mutation. Conclusions: With few treatment options remaining, surveillance for antimicrobial-resistant N. gonorrhoeae is increasingly important, especially among persons at high risk.