P3.237 Direct detection of mosaic pena in clinical samples containing neisseria gonorrhoeae

IntroductionCurrent surveillance of antibiotic resistance in Neisseria gonorrhoeae(NG) relies heavily on the culture of NG. However, culture of NG is challenging due to demanding nutritional and growth requirements of this micro-organism. As a result, surveillance data are limited to only cultured strains while of >50% of Dutch NG positive patients no NG is cultured (data from Dutch Gonococcal Surveillance Program). In this study we compared results from direct detection of mosaic penAwith detection of cultured strains to investigate feasibility of direct molecular resistance surveillance.MethodsA convenience sample of 106 NG positive samples of which positive NG culture results were available (46 urine, 9 genital swabs, 35 anorectal swabs and 16 oropharyngeal swabs) were collected between 2013–2015. Presence of mosaic penAwas determined by real-time PCR. All positive findings were confirmed with sequencing. MICs on cultured NG were determined using E-tests.ResultsLOD determinations of the in-house mosaic penAPCR in comparison to routine NAAT (using COBAS 4800, Roche Diagnostics) showed that the mosaic penAassay was slightly less sensitive than the commercial NAAT. In samples with very low NG loads, mosaic penAdetection might be false-negative. Of 106 NG positive samples, 11 samples showed the presence of mosaic penA(6 urine, 4 oropharyngeal and 1 anorectal swab).Of these 11 samples, NG isolates were re-cultured from 8 samples and all isolates contained the mosaic penAgene. MIC values for ceftriaxone varied between 0.016 and 0.094 mg/L and thus no reduced susceptibility was observed. Although cross-detection with mosaic penAfrom N. meningitidisis possible, no evidence of this was shown in this study.ConclusionIn conclusion, this study indicates that detection of mosaic penAdirectly from clinical samples is feasible and that results match detection of penAfrom clinical isolates obtained from these samples. Direct detection of antibiotic resistance genes would show an insight in resistance surveillance of strains that are not or cannot be cultured.