Introduction Neisseria meningitidis (NM) urethritis presenting clinically as Neisseria gonorrhoeae (NG) urethritis and other NG urogenital infections have been described. NM was isolated from participants in a multi-site gonorrhoea treatment trial.

Methods From February 2014 through November 2014, ninety-two men were enrolled at the LSU site in New Orleans, LA. Urethral and pharyngeal swabs for culture and GenProbe^® CT/GC were collected from all participants and rectal swabs if receptive anal intercourse was reported. There were 424 culture isolates from the trial, 107 of those from LSU. Preliminary isolate NG identification, confirmatory NG/NM identification and NM serotyping were performed at the LSU, UAB and LA OPH Laboratories, respectively. Urethral NG cultures collected in New Orleans from 2013 were reviewed.

Results Eighty-seven (95%), 8 (9%) and 4 (4%) men at the LSU site had positive NG cultures at the urethra, pharynx and rectal sites, respectively. Eight (2%) isolates from the trial were NM and all were from LSU. Eight (8%) LSU isolates were NM from 5 (5%) men. Three (3%) isolates were urethral (Group C-2/Group B-1), 1 (1%) was rectal (Group B-1) and 4 (4%) were pharyngeal isolates (Group B-1/Non-typable-3). One heterosexual and two homosexual men with NM urethritis had purulent discharge and urethral smears identical to gonorrhoea. All Group B isolates were from a vaccinated college student. No NM isolates (0/192) were found in urethral cultures collected in New Orleans in 2013.

Conclusion Reports of urogenital NM infections clinically indistinguishable from NG have increased with changes in sexual practices, particularly increase in oral sex. All men with NM urethritis in this report received oral sex. In most clinical settings NM infection will not be recognised because NAAT testing has replaced culture and Gram stains are seldom performed. In addition, sexually transmitted NM infections may also cluster geographically and in time periods.

Disclosure of interest This study was funded by Melinta Therapeutics.