High Prevalence of Mutations in Quinolone-resistance-determining Regions and mtrR Loci in Polyclonal Neisseria gonorrhoeae Isolates at a Tertiary Hospital in Southern Taiwan
Received 14 January 2009; received in revised form 6 March 2009; accepted 8 June 2009.
Background/Purpose
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.
Conclusion
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.
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aDepartment of Medicine, National Cheng Kung University Medical College, Tainan, Taiwan
bDepartment of Nursing, National Cheng Kung University Medical College, Tainan, Taiwan
cDepartment of Public Health, National Cheng Kung University Medical College, Tainan, Taiwan
dInstitute of Clinical Medicine, National Cheng Kung University Medical College, Tainan, Taiwan
eCenter for Infection Control, National Cheng Kung University Hospital, Tainan, Taiwan
fDepartment of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan
gDepartment of Pathology, National Cheng Kung University Hospital, Tainan, Taiwan
hDepartment of Emergency Medicine, National Cheng Kung University Hospital, Tainan, Taiwan
iDivision of Clinical Research, National Health Research Institutes, Tainan, Taiwan
jJohns Hopkins University School of Medicine, Baltimore, Maryland, USA
Correspondence to: Dr Wen-Chien Ko, Division of Infectious Diseases, Department of Internal Medicine, National Cheng Kung University Hospital, 138 Sheng Li Road, Tainan 704, Taiwan
ABSTRACT