Reduced clinical efficacy of pazufloxacin against gonorrhea due to high prevalence of quinolone-resistant isolates with the GyrA mutation. The Pazufloxacin STD Group.
Forty-two men with gonococcal urethritis were treated with an oral dosage of 200 mg of pazufloxacin, a new fluoroquinolone, three times daily for 3 days. Only 28 of the 42 men (66.7%) had negative culture results for Neisseria gonorrhoeae during follow-up. Of the 42 isolates, 41 could be recultured for antibiotic susceptibility testing and DNA sequencing. In 26 of the 41 isolates (63.4%), GyrA mutations with or without ParC mutations were identified. Among the 26 isolates, 23 contained a single GyrA mutation, 1 contained two GyrA mutations, and 2 contained three mutations including double GyrA and single ParC mutations. A single Ser-91-to-Phe mutation, which was detected in 14 of the 26 isolates, was the most common GyrA mutation, followed by an Ala-75 to Ser mutation and an Asp-95 to Asn or Gly mutation in GyrA. All three isolates with two or three mutations contained the Ser-91-to-Phe GyrA mutation. Eleven of the 14 isolates with the single Ser-91-to-Phe mutation within GyrA and all 3 isolates with two or three mutations persisted after pazufloxacin treatment. On the other hand, all 15 wild-type and 9 mutant isolates with a substitution at codon Ala-75 or Asp-95 were eradicated. The mean MIC of pazufloxacin for mutants with the single Ser-91-to-Phe mutation in GyrA was 66-fold higher than that for the wild type. The results obtained in this study suggest that a high prevalence of fluoroquinolone-resistant gonococcal isolates with the Ser-91-to-Phe mutation in GyrA reduced the efficacy of pazufloxacin as treatment for gonococcal urethritis.
Tanaka
M
M
Department of Urology, Faculty of Medicine, Kyushu University, Fukuoka, Japan. masatosh@uro.med.kyushu-u.ac.jp
Matsumoto
T
T
Sakumoto
M
M
Takahashi
K
K
Saika
T
T
Kabayashi
I
I
Kumazawa
J
J
D000328:Adult; D000890:Anti-Infective Agents / Q000494:pharmacology / Q000627:therapeutic use*; D027081:DNA Gyrase; D027101:DNA Topoisomerase IV; D004250:DNA Topoisomerases, Type II / Q000235:genetics*; D004352:Drug Resistance, Microbial / Q000235:genetics; D024841:Fluoroquinolones; D006069:Gonorrhea / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009154:Mutation; D009344:Neisseria gonorrhoeae / Q000187:drug effects* / Q000235:genetics; D010078:Oxazines / Q000494:pharmacology / Q000627:therapeutic use*; D016896:Treatment Outcome
D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D010078:Oxazines; C078052:pazufloxacin; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase; D004250:DNA Topoisomerases, Type II