Methods: Adult men with urethral discharge were enrolled from February through September 2014. Urine specimens for NAAT, and urethral swabs for Gram stain, GC culture on MTM medium, and GC culture on the InTray™ GC system were obtained. Order of specimen collection (MTM or InTray™) was alternated. Plates were incubated at 37°C for up to 48 hours and examined for growth. Sensitivity of the InTray™ GC system and MTM were determined, defining a true GC positive as ≥2 positive results among NAAT, Gram stain, MTM, and InTray™. The relative performance of the MTM and InTray™ GC system was assessed with McNemar’s Test.
Results: Of 190 specimens, 112 (58.9%) were determined to be true GC positives. Among these 112 positives, the overall sensitivity of the MTM was 97.3% and the InTray™ GC system was 87.5%. There were 96/112 (85.7%) specimens with positively concordant results (MTM+/InTray™+). Fifteen specimens were discordant (2 were MTM−/InTray™+ and 13 were MTM+/InTray™−). One GC case was missed by both (MTM−/InTray™−). MTM performed significantly better than the InTray™ GC system (p=0.007) for diagnosis of GC.
Conclusion: MTM agar had a higher sensitivity than the InTray™ GC system for the culture of GC among men with symptomatic urethral GC. MTM agar remains the gold standard medium for GC diagnosis via culture. The InTray™ GC system is an FDA-approved option which could improve access to GC culture for clinics and public health STD programs.
Donation of test kits
S. Gose, None
T. Noohi, BioMed Diagnostics: Investigator , Donation of test kits
I. Park, BioMed Diagnostics: Investigator , Donation of test kits
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