Associations between antimicrobial susceptibility/resistance of Neisseria gonorrhoeae isolates in European Union/European Economic Area and patients' gender, sexual orientation and anatomical site of infection, 2009-2016.

BACKGROUND: The emergence and spread of antimicrobial resistance (AMR) in Neisseria gonorrhoeae, nationally and internationally, is a serious threat to the management and control of gonorrhoea. Limited and conflicting data regarding the epidemiological drivers of gonococcal AMR internationally have been published. We examined the antimicrobial susceptibility/resistance of gonococcal isolates (n = 15,803) collected across 27 European Union/European Economic Area (EU/EEA) countries in 2009-2016, in conjunction to epidemiological and clinical data of the corresponding patients, to elucidate associations between antimicrobial susceptibility/resistance and patients' gender, sexual orientation and anatomical site of infection. METHODS: In total, 15,803 N. gonorrhoeae isolates from the European Gonococcal Antimicrobial Surveillance Programme (Euro-GASP), 2009-2016, were examined. Associations between gonococcal susceptibility/resistance and patients' gender, sexual orientation and anatomical site of infection were investigated using univariate and multivariate logistic regression analysis. Statistical significance was determined by Pearson χ2-test or Fisher's exact test with two-tailed p-values of < 0.05 indicating significance. RESULTS: The overall gonococcal resistance from 2009 to 2016 was 51.7% (range during the years: 46.5-63.5%), 7.1% (4.5-13.2%), 4.3% (1.8-8.7%), and 0.2% (0.0-0.5%) to ciprofloxacin, azithromycin, cefixime, and ceftriaxone, respectively. The level of resistance combined with decreased susceptibility to ceftriaxone was 10.2% (5.7-15.5%). Resistance to cefixime and ciprofloxacin, and resistance combined with decreased susceptibility to ceftriaxone were positively associated with urogenital infections and heterosexual males, males with sexual orientation not reported and females (except for ciprofloxacin), i.e. when compared to men-who-have-sex-with-men (MSM). Azithromycin resistance was positively associated with heterosexual males, but no association was significant regarding anatomical site of infection. CONCLUSIONS: Overall, sexual orientation was the main variable associated with gonococcal AMR. Strongest positive associations were identified with heterosexual patients, particularly males, and not MSM. To provide evidence-based understanding and mitigate gonococcal AMR emergence and spread, associations between antimicrobial susceptibility/resistance and patients' gender, sexual orientation and anatomical site of infection need to be further investigated in different geographic settings. In general, these insights will support identification of groups at increased risk and targeted public health actions such as intensified screening, 3-site testing using molecular diagnostics, sexual contact tracing, and surveillance of treatment failures.

The European gonococcal antimicrobial surveillance programme (Euro-GASP) appropriately reflects the antimicrobial resistance situation for Neisseria gonorrhoeae in the European Union/European Economic Area.

BACKGROUND: European Gonococcal Antimicrobial Surveillance Programme (Euro-GASP) antimicrobial resistance (AMR) data are used to inform gonorrhoea treatment guidelines; therefore the data need to be robust and representative. We assessed the extent to which Euro-GASP reflects national measures of the AMR situation for Neisseria gonorrhoeae across the European Union/European Economic Area (EU/EEA). METHODS: We compared data from Euro-GASP with published national gonococcal AMR data from 15 countries for azithromycin, cefixime and ciprofloxacin for the period 2009 to 2013 and performed Poisson regression to identify differences (p < 0.05) between the proportions of resistant isolates. The 2014 Euro-GASP AMR data for each country (n = 19) were weighted to account for differences in the distribution of patient characteristics between Euro-GASP and EU/EEA epidemiological gonorrhoea surveillance data. Data were compared to determine whether estimates of resistance levels differed with regards to the 5% threshold used to assess the clinical utility of first-line gonorrhoea treatments. We assessed the quality of decentralised testing by comparing AMR data for isolates tested both centrally and in the participating laboratories, and by evaluating external quality assessment (EQA) performance. RESULTS: There was no significant difference for azithromycin, cefixime and ciprofloxacin resistance when Euro-GASP country data were compared with data from national reports. Weighting slightly altered the Euro-GASP AMR estimates (by between - 4.7 and 4.7% from the unweighted estimates). Weighting resulted in greater changes in estimates of resistance to azithromycin (from - 9.5 to 2.7%) and ciprofloxacin (from - 14.8 to 17.9%) in countries with low isolate numbers and low completeness of reporting (n = 3). Weighting caused AMR levels to fall below or above the 5% threshold for cefixime or azithromycin, respectively in only two countries. Susceptibility category data submitted from the decentralised Euro-GASP laboratories were concordant with the Euro-GASP data (> 90%). EQA performance was also good; < 5% of the minimum inhibitory concentration (MIC) results differed by > 4-fold from the modal MIC of the EQA isolate. CONCLUSIONS: The overall prevalence of AMR reported by Euro-GASP reflects closely the AMR situation for N. gonorrhoeae in the EU/EEA. Euro-GASP data can be used to provide robust AMR estimates to inform the European guideline for the management of gonorrhoea.

Ten years of external quality assessment (EQA) of Neisseria gonorrhoeae antimicrobial susceptibility testing in Europe elucidate high reliability of data.

BACKGROUND: Confidence in any diagnostic and antimicrobial susceptibility testing data is provided by appropriate and regular quality assurance (QA) procedures. In Europe, the European Gonococcal Antimicrobial Susceptibility Programme (Euro-GASP) has been monitoring the antimicrobial susceptibility in Neisseria gonorrhoeae since 2004. Euro-GASP includes an external quality assessment (EQA) scheme as an essential component for a quality-assured laboratory-based surveillance programme. Participation in the EQA scheme enables any problems with the performed antimicrobial susceptibility testing to be identified and addressed, feeds into the curricula of laboratory training organised by the Euro-GASP network, and assesses the capacity of individual laboratories to detect emerging new, rare and increasing antimicrobial resistance phenotypes. Participant performance in the Euro-GASP EQA scheme over a 10 year period (2007 to 2016, no EQA in 2013) was evaluated. METHODS: Antimicrobial susceptibility category and MIC results from the first 5 years (2007-2011) of the Euro-GASP EQA were compared with the latter 5 years (2012-2016). These time periods were selected to assess the impact of the 2012 European Union case definitions for the reporting of antimicrobial susceptibility. RESULTS: Antimicrobial susceptibility category agreement in each year was ≥91%. Discrepancies in susceptibility categories were generally because the MICs for EQA panel isolates were on or very close to the susceptibility or resistance breakpoints. A high proportion of isolates tested over the 10 years were within one (≥90%) or two (≥97%) MIC log2 dilutions of the modal MIC, respectively. The most common method used was Etest on GC agar base. There was a shift to using breakpoints published by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) in the latter 5 years, however overall impact on the validity of results was limited, as the percentage categorical agreement and MIC concordance changed very little between the two five-year periods. CONCLUSIONS: The high level of comparability of results in this EQA scheme indicates that high quality data are produced by the Euro-GASP participants and gives confidence in susceptibility and resistance data generated by laboratories performing decentralised testing.

Performance characteristics of newer MIC gradient strip tests compared with the Etest for antimicrobial susceptibility testing of Neisseria gonorrhoeae.

For Neisseria gonorrhoeae susceptibility testing, Etest, comparable to agar dilution, is frequently used. In recent years, newer MIC gradient strip tests have been commercialized. However, these tests have not been appropriately evaluated for gonococci. We evaluated the sensitivity, specificity, accuracy, quality, availability of antimicrobials and cost of the MIC Test Strip (Liofilchem), M.I.C.Evaluator (Oxoid) and Ezy MIC Strip (HiMedia), compared to the reference Etest (bioMérieux), for gonococcal susceptibility testing. The MICs of eight antimicrobials in 103 gonococcal international reference strains (n = 29) and clinical isolates (n = 74) were examined. Coefficient of determination (R2 ), complete agreement, essential agreement, SIR categorical agreement, sensitivity, specificity and accuracy were calculated. R2 of the MICs for the antimicrobials ranged between 0.674-0.996, 0.617-0.993, and 0.643-0.994 for the MIC Test Strip, M.I.C.Evaluator strips and Ezy MIC Strips respectively. The essential agreement (SIR categorical agreement) was 99.6% (88.6%), 100% (87.1%) and 93.0% (83.1%) respectively. M.I.C.Evaluator strips for gonococcal key antimicrobials were lacking and the Ezy MIC Strips showed an inconsistent accuracy, quality and some strips were contaminated. The Liofilchem MIC Test Strips had limitations, but might be relatively accurate alternatives to Etest for gonococci. Strict quality assurance (at manufacturing and testing laboratory), including quality controls, are required.