Factors associated with anitmicrobial resistant gonorrheoea infections in men who have sex with men in Switzerland: case control study

Abstract

Introduction Antibiotic resistant Neisseria gonorrhoeae (NG) is a global public health challenge; resistance has emerged to all antibiotics used for empirical treatment. In Switzerland, gonorrhoea reports increased from 404 in 2000 to 1895 in 2015, with about 40% in men who have sex with men (MSM). To our knowledge, no studies have examined factors associated with antibiotic resistant NG in Switzerland. Methods We enrolled MSM at clinics in Zurich and Bern from May 2015 to June 2016 presenting with symptoms suggestive of NG, partners of known cases or had a positive NG screening test. MSM completed an online questionnaire on social and behavioural factors and physicians completed a case report form. Specimens from pharynx, rectum and urethra were tested with a molecular test and culture. For culture positive specimens, the minimum inhibitory concentration (MIC) for different antibiotics was determined, using EUCAST 2017 resistance breakpoints for ciprofloxacin, ceftriaxone, cefixime and spectinomycin, and ≥2mg/L for azithromycin (as in a European study). We also examined reduced susceptibility to ceftriaxone (cutoff ≥0.016 mg/L). Cases were MSM with NG and MIC above the breakpoint, controls were MSM with NG and MIC less than or equal to the breakpoint. We used logistic regression to estimate odds ratios (OR) with 95% confidence intervals (CI). Results In total, 164/230 (71%) MSM were positive for NG; culture was positive in 118/164. We compared 45 (39%) cases with ciprofloxacin resistance with 73 controls. Cases were more likely than controls to have concurrent sexual partners (OR 2.2, 95%Cl 0.876.0, p=0.13), to have received oral sex (OR 5.3, 0.644.2, p=0.08), to have had sex abroad in the last three months (OR 2.3, 1.04.9, p=0.08) and for the most recent partner to be casual (OR 2.6, 0.88.5 p=0.08). One NG isolate was azithromycin resistant. No isolates were resistant to spectinomycin, cefixime or ceftriaxone; 21 (18%) had reduced susceptibility to ceftriaxone, but we found no associations with clinical or behavioural factors. Conclusions This study had a limited sample size but is the first in Switzerland to link behavioural factors with antibiotic resistant NG. Ciprofloxacin resistance was common in MSM and there is evidence of reduced susceptibility to ceftriaxone. Interventions for MSM to promote safer sex, especially whilst abroad, and enhanced surveillance of antimicrobial susceptibility could help to identify and control emerging resistance in NG.