Identification of novel mutation patterns in the parC gene of ciprofloxacin-resistant isolates of Neisseria gonorrhoeae.

Of 65 ciprofloxacin-resistant, clinical isolates of Neisseria gonorrhoeae, 5 isolates exhibited ParC mutations previously undescribed in the gonococcus. For isolates containing two ParC mutations (the Ser-87-->Ile and Glu-91-->Gly mutations and the Gly-85-->Cys and Arg116-->Leu mutations) the MICs of ciprofloxacin (8.0 to 64.0 microg/ml) were higher than those for the isolate containing the single ParC mutation (Arg-116-->Leu; MIC, 1.0 microg/ml).