Neisseria gonorrhoeae with decreased susceptibility to ciprofloxacin in British Columbia: an imported phenomenon.

According to current interpretive criteria, Neisseria gonorrhoeae isolates with ciprofloxacin minimum inhibitory concentrations (MICs) of ≤ 0.06 μg/mL are considered susceptible. Intermediate and resistant MIC breakpoints have not yet been established but isolates of N. gonorrhoeae with ciprofloxacin MICs of 0.05 to 0.25 μg/mL have been associated with apparent treatment failure with a regimen of a single 250 mg dose. A report from Australia has also documented a strain with a ciprofloxacin MIC of 1.0 μg/mL that failed to respond to treatment with 500 mg of ciprofloxacin. In Canada, as early as 1989, six penicillinase-producing N. gonorrhoeae (PPNG) isolates submitted to the National Laboratory for Sexually Transmitted Disease, Laboratory Centre for Disease Control, showed decreased susceptibility to fluoroquinolones. These isolates exhibited ciprofloxacin MICs of 0.25 to 0.5 μg/mL and were all recovered from male patients infected outside the country.