High prevalence of mutations in quinolone-resistance-determining regions and mtrR loci in polyclonal Neisseria gonorrhoeae isolates at a tertiary hospital in Southern Taiwan.
OBJECTIVE
The emergence of multidrug-resistant Neisseria gonorrhoeae is a great challenge in controlling gonorrhea. This study was conducted to survey the prevalence of molecular mechanisms of antimicrobial resistance among 45 clinical isolates of N. gonorrhoeae collected at a university hospital in Southern Taiwan during 1999-2004.


METHODS
Mutations in mtrR loci and quinolone-resistance-determining regions (QRDRs) were examined by gene sequencing. Polymerase chain reactions with specific primers were performed to detect ermA, ermB, ermC, and ermF. Serogroups and serovars were determined by commercial kits.


RESULTS
The percentage of multidrug resistance, that is, resistance to penicillin, tetracycline, erythromycin, and ciprofloxacin, among the 45 isolates was 40%. Ceftriaxone and spectinomycin were active against all isolates in vitro. The frequency of mutations in the QRDR and mtrR promoter was 82.2% and 93.3%, respectively. Eighty-two percent of the isolates carried mutations both in the QRDR and mtrR loci. Of nine mutation profiles with QRDR mutations (n =37), gyrA-Ser91Phe/gyrA-Asp95Gly/parC-Ser87Arg was the most common type (56.8%). Acquired genes for rRNA methylase were detected in 11 isolates (10 ermB and 1 ermA). Twenty-seven serovars were identified and all belonged to serogroup B, which suggested that multiple clones of N. gonorrhoeae were circulating in the community in the Tainan area.


CONCLUSIONS
The high prevalence of multidrug resistance caused by varied resistance mechanisms in N. gonorrhoeae limits the drug choice. Ongoing surveillance of antimicrobial resistance and discovery of new effective antibiotic therapy are warranted in endemic areas.
Chen
Po-Lin
PL
Department of Medicine, National Cheng Kung University Medical College, Tainan, Taiwan.
Lee
Hsin-Chun
HC
Yan
Jing-Jou
JJ
Hsieh
Yu-Hsiang
YH
Lee
Nan-Yao
NY
Ko
Nai-Ying
NY
Lin
Chia-Wei
CW
Chang
Chia-Ming
CM
Wu
Chi-Jung
CJ
Lee
Ching-Chi
CC
Ko
Wen-Chien
WC
D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001426:Bacterial Proteins / Q000235:genetics; D004269:DNA, Bacterial / Q000187:drug effects / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects / Q000235:genetics*; D005260:Female; D006069:Gonorrhea / Q000188:drug therapy* / Q000453:epidemiology / Q000235:genetics / Q000382:microbiology; D006785:Hospitals, University; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D009344:Neisseria gonorrhoeae / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D015995:Prevalence; D015363:Quinolones / Q000494:pharmacology* / Q000627:therapeutic use; D012097:Repressor Proteins / Q000235:genetics; D017422:Sequence Analysis, DNA; D013624:Taiwan / Q000453:epidemiology
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D015363:Quinolones; D012097:Repressor Proteins; C087450:mtrR protein, Neisseria gonorrhoeae