Trends of chromosomally mediated antimicrobial resistance in Neisseria gonorrhoeae in Canada: 1994-1999.

Background and Objectives: We monitored the trends of chromosomally mediated resistant Neisseria gonorrhoeae (CMRNG) in Canada. Chromosomally resistant N. gonorrhoeae (CMRNG) were defined as having resistance to 3 antibiotics: penicillin (minimum inhibitory concentration [MIC] greater than or equal to2.0 mg/L), tetracycline (MIC greater than or equal to2.0 mg/L and less than or equal to8.0 mg/L), and erythromycin (MIC greater than or equal to2.0 mg/L). Goal: The goal was to provide surveillance data for public health interventions for the control of gonococcal infections. Study Design: Antibiotic susceptibility tests were performed on N. gonorrhoeae isolates obtained from 1994 to 1999 in Canada. Strains were further characterized by auxotype (A), serovar (S), and plasmid profile (P). Results: Between 1994 and 1999, 19.2% of strains were CMRNG, 12.9% had a combined resistance to tetracycline and erythromycin, and 4.7% were resistant to tetracycline. The incidence of ciprofloxacin resistance and azithromycin resistance was 2.3% and 0.8%, respectively. Conclusion: This survey of N. gonorrhoeae provides strain characterization data and temporal trends of strains in the Canadian population. CMRNG strains are on the rise, and the continual monitoring and characterization of these strains is important for the evaluation of current recommended antibiotic therapies used in Canada.