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D7.5 Cephalosporin and Azithromycin Susceptibility in Neisseria Gonorrhoeae Isolates by Site of Infection, British Columbia, 2006-2011

Thursday, March 15, 2012: 9:18 AM
Greenway Ballroom H/I/J
Travis Salway Hottes, MSc1, Richard T. Lester, MD, FRCPC1, Linda MN Hoang, MSc, MD, FRCPC2, Rachel McKay, MSc3, Miguel Imperial, MD, FRCPC2, Mark Gilbert, MD, MHSc, FRCPC1, David Patrick, MD, FRCPC, MHSc3, Tom Wong, MD, MPH, FRCPC4, Irene Martin, BSc5 and Gina Ogilvie, MD, MSc, CCFP, FCFP, DrPH(C)1, 1Clinical Prevention Services, British Columbia Centre for Disease Control, Vancouver, BC, Canada, 2Laboratory Services, British Columbia Centre for Disease Control, Vancouver, BC, Canada, 3Communicable Disease Prevention and Control Services, British Columbia Centre for Disease Control, Vancouver, BC, Canada, 4Public Health Agency of Canada, Ottawa, ON, Canada, 5National Microbiology Laboratory, Winnipeg, MB, Canada

     

Background:Widespread resistance of Neisseria gonorrhoeae to penicillin, tetracycline, and fluoroquinolones has challenged effective treatment and control; recent international case reports of cefixime, ceftriaxone, and azithromycin resistance suggest remaining treatment options are now additionally threatened.

Objectives:To explore trends in antimicrobial susceptibility of N. gonorrhoeae we reviewed provincial laboratory data from British Columbia, 2006-2011.

Methods:Susceptibility testing was performed for all N. gonorrhoeae isolated by culture in-house or forwarded to the provincial laboratory. Standard breakpoints defined resistance or intermediate-resistance (non-susceptibility) for penicillin, tetracycline, ciprofloxacin, and spectinomycin. Elevated minimum inhibitory concentrations (MIC) at serial dilutions ≥0.064 were explored for cefixime/ceftriaxone, and ≥0.5 for azithromycin. Non-susceptibility/elevated MIC was compared by year, site of infection, sex, and age.

Results:1334 isolates representing ~20% of all reported gonorrhea cases were analyzed. Non-susceptibility to penicillin was established at baseline. Non-susceptibility to tetracycline and ciprofloxacin increased over the period of study, reaching 93% and 69%, respectively, in 2010. All isolates were susceptible to spectinomycin. None had MIC ≥0.5 for cefixime or ceftriaxone, and only 1% had MIC ≥2.0 for azithromycin; however, elevated MIC to these agents showed a steady geometric rise, particularly in 2009-10 (43% cefixime/33% ceftriaxone MIC ≥0.064, 76% azithromycin MIC ≥0.5, 2010). Non-susceptibility (penicillin/tetracycline/ciprofloxacin) and elevated MIC (cefixime/ceftriaxone/azithromycin) were consistently higher among males versus females and highest at rectal and pharyngeal sites. 2011 data will be presented.

Conclusions:Increases in elevated MIC to cefixime/ceftriaxone/azithromycin were superimposed on a background of established resistance to penicillin, tetracycline, and ciprofloxacin, and could be a warning sign of impending gonococcal resistance to first-line treatments.

Implications for Programs, Policy, and Research:Results underscore the need for timely evolution of treatment recommendations and substantiate distinct treatment strategies based on site of infection/sex. Ongoing surveillance is critical and may benefit from enhancements including linkage to epidemiological/clinical details and novel methods for measuring resistance in NAAT-positive specimens.

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