(P80) A Chocolate Agar Slant-Paraffin Oil Transport Medium Supports Viability of Neisseria gonorrheoae for 72 hours

Background: Neisseria gonorrhoeae (Ng) culture plays a central role in Ng antimicrobial resistance surveillance and guiding the clinical management of resistant Ng infections. However, the maximum survival of Ng in commercially available transport systems is 12-24 hours, limiting the utility of Ng culture. We evaluated the performance of a chocolate agar slant-paraffin oil as a transport system for urethral discharge specimens for Ng culture and assessed Ng survival after holding specimens for 5 or 7 days at ambient temperature.

Methods: From February 2022 to January 2023, we collected urethral specimens from patients presenting to the municipal Sexual Health Clinic (SHC) in Seattle, WA who had urethral discharge and Gram-negative diplococci on Gram stain. Two urethral discharge specimens were collected: the first used a Puritan polyester-based swab for collection of penile discharge specimen and was placed in a BBL chocolate agar slant with 1 ml of sterilized Sigma paraffin oil; the second urethral swab collected using a Puritan aluminum wire swab was first used to inoculate Thayer-Martin (MTM) agar plate at bedside for clinical Ng culture, then placed in a separate chocolate agar slant-paraffin oil. Study specimens were sent to the laboratory at ambient temperature within 1-12 hours, where they were maintained at ambient temperature and cultured for Ng on MTM agar 24 hours after collection (Day 1), Day 2, Day 3, and Day 5 or Day 7 (After the first 50 specimens were held for 7 days with low Ng recovery, we switched to holding for 5 days only). Ng species confirmation was performed by API NH and/MALDI-TOF.

Results: We tested a total of 91 specimens from 87 patients. Most (85/91, 93%) had a clinical Ng culture performed (78/85, 92% Ng-positive), 6/91 (7%) were missing a clinical Ng culture. Slant-paraffin Ng positivity at 1, 2, 3, 5, and 7 days were 88% (80/91), 81% (74/91), 77% (70/91), 27% (11/41), 10% (5/50), respectively (Table). Slant-paraffin Ng positivity did not vary between the two urethral discharge specimen types.

Conclusion: Chocolate agar slant-paraffin oil can maintain Ng viability and allow robust recovery of Ng for 72 hours. Ng viability diminished significantly after 72 hours.