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[Quinolone-resistant mutations in Neisseria gonorrhoeae]
S Onodera1, K Kishimoto, H Kiyota
1Department of Urology, Jikei University School of Medicine, Tokyo, Japan.
Summary
New quinolone resistance in Neisseria gonorrhoeae is linked to specific gyrA gene mutations. These genetic changes in gonococcal strains mirror those found in E. coli, suggesting a common resistance mechanism.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Neisseria gonorrhoeae strains show decreased susceptibility to new quinolones.
- Gonococcal urethritis patients provided isolates between February 1991 and January 1992.
- Understanding quinolone resistance mechanisms in N. gonorrhoeae is crucial.
Purpose of the Study:
- Investigate the mechanisms of new quinolone resistance development in N. gonorrhoeae.
- Identify specific genetic mutations associated with quinolone resistance.
- Examine the correlation between quinolone use and the spread of resistant strains.
Main Methods:
- Selected 3 new quinolone-resistant, penicillin-sensitive N. gonorrhoeae strains.
- Performed transformation experiments using a plasmid with the E. coli gyrA gene.
- Determined the base sequence of the N. gonorrhoeae gyrA gene via PCR.
Main Results:
- Two of three strains yielded transformants after genetic manipulation.
- One transformant showed an eightfold increase in sensitivity to norfloxacin (NFLX).
- Identified specific gyrA gene mutations: Ser83Phe in two strains, and Asp87Gly in one strain.
Conclusions:
- Specific mutations in the N. gonorrhoeae gyrA gene are associated with quinolone resistance.
- These mutations show homology to those found in other bacteria like E. coli.
- Increased quinolone usage correlates with the prevalence of resistant N. gonorrhoeae strains.