title: Analysis of Neisseria gonorrhoeae azithromycin susceptibility in the United States by the Gonococcal Isolate Surveillance Project, 2005 to 2013.
abstract: Azithromycin, administered with ceftriaxone, is recommended by the CDC for the treatment of gonorrhea. Many experts have expressed concern about the ease with which Neisseria gonorrhoeae can acquire macrolide resistance. We sought to describe gonococcal azithromycin susceptibility in the United States and to determine whether azithromycin susceptibility has changed over time. We analyzed data from 2005 to 2013 from the Gonococcal Isolate Surveillance Project, a CDC-supported sentinel surveillance network that monitors gonococcal antimicrobial susceptibility. A total of 44,144 N. gonorrhoeae isolates were tested for azithromycin susceptibility by agar dilution methods. The overall azithromycin MIC50 was 0.25 μg/ml, and the MIC90 was 0.5 μg/ml. There were no overall temporal trends in geometric means. Isolates from men who had sex with men had significantly higher geometric mean MICs than isolates from men who had sex exclusively with women. The overall prevalence of reduced azithromycin susceptibility (MIC, ≥2 μg/ml) was 0.4% and varied by year from 0.3% (2006 and 2009) to 0.6% (2013). We did not find a clear temporal trend in gonococcal azithromycin MICs in the United States, and the prevalence of reduced azithromycin susceptibility remains low. These findings support the continued use of azithromycin in a combination therapy regimen for gonorrhea.
authors.affiliation: Division of STD Prevention, Centers for Disease Control and Prevention, U.S. Department of Health and Human Services, Atlanta, Georgia, USA rkirkcaldy@cdc.gov.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Kirkcaldy
authors.affiliation: University of Washington, Seattle, Washington, USA.
authors.forename: Olusegun
authors.initials: O
authors.lastname: Soge
authors.affiliation: Division of STD Prevention, Centers for Disease Control and Prevention, U.S. Department of Health and Human Services, Atlanta, Georgia, USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Papp
authors.affiliation: University of Alabama and Jefferson County Department of Health, Birmingham, Alabama, USA.
authors.forename: Edward W
authors.initials: EW
authors.lastname: Hook
authors.affiliation: Emory University, Atlanta, Georgia, USA.
authors.forename: Carlos
authors.initials: C
authors.lastname: del Rio
authors.affiliation: Texas Department of State Health Services, Austin, Texas, USA.
authors.forename: Grace
authors.initials: G
authors.lastname: Kubin
authors.affiliation: Division of STD Prevention, Centers for Disease Control and Prevention, U.S. Department of Health and Human Services, Atlanta, Georgia, USA.
authors.forename: Hillard S
authors.initials: HS
authors.lastname: Weinstock
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017963:Azithromycin / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D009344:Neisseria gonorrhoeae / Q000187:drug effects*; D014481:United States; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D017963:Azithromycin