3F2 Cluster of Neisseria Gonorrhoeae Isolates with High-Level Azithromycin Resistance and Decreased Ceftriaxone Susceptibility

Thursday, September 22, 2016: 11:00 AM
Room 208/209
Alan Katz, MD, MPH1, Alan Komeya, MPH2, Juval Tomas, RN, MSN, MPH2, A. Christian Whelen, PhD3, Robert Kirkcaldy, MD, MPH4, Olusegun Soge, PhD5, Glenn Wasserman, MD, MPH6, Norman O'Connor, MA3, Pamela O'Brien, BS3, Douglas Sato, BA3, Eloisa Maningas, BSMT3, Gail Kunimoto, BS3 and John Papp, PhD7, 1Department of Public Health Sciences, University of Hawaii, Honolulu, HI, 2Diamond Head STD Clinic, Hawaii Department of Health, Honolulu, HI, 3State Laboratories Division, Hawaii Department of Health, Pearl City, HI, 4Surveillance and Special Studies Team, Surveillance and Data Management Branch, Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, 5Global Health STI Laboratory, University of Washington, Seattle, WA, 6Communicable Disease and Public Health Nursing Division, Hawaii Department of Health, Honolulu, HI, 7Laboratory Reference and Research Branch, Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA

Background:  CDC currently recommends dual therapy with ceftriaxone and azithromycin for gonorrhea to treat possible chlamydia and slow emergence of antimicrobial resistance. Hawaii reported the first US Neisseria gonorrhoeae (NG) isolate with high-level azithromycin resistance in 2011. Since 2014, the prevalence of reduced azithromycin susceptibility increased in the US; however, these strains were highly susceptible to cephalosporins. We now report 7 recent patients with NG isolates demonstrating high-level azithromycin resistance, 6 of which exhibited decreased ceftriaxone susceptibility.

Methods:  Isolates were collected during 21 April through 10 May 2016 in Hawaii Department of Health’s (HDOH) STD clinic (n=5) and 2 private practice settings (n=2). Antimicrobial susceptibility testing was conducted by Etest by HDOH’s State Laboratory Division, which routinely conducts Etest on all submitted gonococcal isolates. Azithromycin minimum inhibitory concentrations (MICs) of >256 µg/ml were considered high-level resistance; ceftriaxone MICs of ≥0.125 µg/ml were considered reduced susceptibility. Patients were interviewed and when possible, partners were interviewed, tested, and treated.

Results:  The isolates were recovered from 7 persons in Honolulu, Hawaii (6 males and 1 female). None of the patients reported partners in common, recent travel, or antibiotic use; no male patients reported same sex contact. All patients were symptomatic (dysuria and penile discharge or vaginal discharge).  All isolates exhibited high-level azithromycin resistance. All were β-lactamase positive; 6 demonstrated decreased ceftriaxone susceptibility. Preliminary pulsed-field gel electrophoresis patterns were indistinguishable. All patients were treated with 250 mg ceftriaxone and 1 g azithromycin. Six of the 7 were followed-up at the STD clinic: all had negative cultures and NAATs. The remaining patient refused follow-up testing, but reported post-treatment symptom resolution.

Conclusions:  Hawaii’s laboratory-based surveillance of gonococcal susceptibility is instrumental in detecting gonococcal resistance. This cluster of genetically related isolates with both decreased ceftriaxone susceptibility and high-level azithromycin resistance in case-patients without known epidemiological commonality is disconcerting.