Characterization of proline, citrulline, and uracil auxotrophic plasmid-carrying Neisseria gonorrhoeae strains in Canada, 1993-2003.

Background and Objective: Proline, citrulline, and uracil (PCU-) Neisseria gonorrhoeae is a common auxotroph in Canada and resistance to antibiotics in this auxotroph is rare. Goal: The goal of this study was to determine the characteristics of the PCU- strains that have plasmids. Study Design: PCU- strains sent between 1993 and 2003 for reference work to the National Microbiology Laboratory were analyzed for their plasmid profiles and antimicrobial susceptibilities. PCU- strains containing plasmids and/or antimicrobial resistant were serotyped, and por and tbpB genes were sequenced to determine their antigenic types. Results: Forty strains containing plasmids were identified; serotype IB-11 and por/tbpB sequence type 2 was the most common pattern (28 of 40 strains [70%]). One strain had plasmids that conferred resistance to penicillin and tetracycline and 4 plasmidless strains were resistant to tetracycline. Conclusion: PCU- auxotrophic N. gonorrhoeae carrying plasmids and/or that have chromosomal genes mutated to resist antimicrobials have been identified in Canada. This shows the competency of this pathogen to survive under antimicrobial pressure and the importance of continuous surveillance.