420. Prevalence of Oropharyngeal Meningococcal Carriage in an Urban STD Clinic

BACKGROUND: Neisseria meningitidis (Nm) can cause invasive disease, but it also asymptomatically colonizes the pharynx in approximately 10% of the general population. Older studies have reported higher carriage rates (>30%) among individuals attending sexually transmitted disease (STD) clinics. This study examined the prevalence of oropharyngeal Nm carriage in STD clinic attendees in Columbus, Ohio. METHODS: Per normal procedures, all patients presenting for care in the STD clinic who report oral sex in the last year are screened for oropharyngeal Neisseria gonorrhoeae (Ng) using nucleic acid amplification testing (NAAT). For the same patients, we also initiate cultures using media selective for Neisseria spp. Analytical Profile Index Neisseria-Haemophilus (API NH) and Nm-specific PCR screening is performed on colonies with oxidase-positive Gram-negative diplococci to distinguish between Ng and Nm. For this study, we then performed PCR-based genogrouping on confirmed Nm isolates. RESULTS: Between July 2018 and March 2019, oropharyngeal screening occurred at 5,015 patient visits and oropharyngeal Nm was detected at 163 visits (3.3%). Nm-positive individuals were primarily male (69.9%), Caucasian (62.6%), with non-Hispanic ethnicity (98.8%). The median age was 27 years and 5.5% were HIV-positive. Among male cases, 49.1% reported sex with men; among women, 98.0% reported sex with men. Meningococcal vaccination status was unknown for 71.2%, but 26.4% had documentation of prior MenACWY vaccination and 2.3% had prior MenB vaccination. Among the 163 cases, genogroup distribution was 23.9% B, 10.4% E, 9.8% Z, 3.1% C, 0.0% W, 0.0% Y, and 39.3% capsule null locus. For 13.5%, the selected screening approach could not determine genogroup. CONCLUSION: In STD clinic patients reporting recent oral sex, we found a much lower prevalence of oropharyngeal Nm carriage compared with what has been reported historically for similar populations. While NmB was the most common capsular type identified by genogrouping, almost 40% of Nm isolates contained the capsule null locus, making them unable to express capsule. Additional studies should evaluate the effect of Nm vaccination programs on carriage among STD-clinic attendees. DISCLOSURES: All authors: No reported disclosures.