Antimicrob. Agents Chemother. doi:10.1128/AAC.00020-08
Copyright (c) 2008, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.
Genotyping as a tool for antibiotic resistance surveillance of Neisseria gonorrhoeae in New Caledonia: evidence of a novel genotype associated with reduced penicillin susceptibility
Frédérique VERNEL-PAUILLAC,
Sobhan NANDI,
Robert A. NICHOLAS,
and
Cyrille GOARANT*
Institut Pasteur de Nouvelle-Calédonie, Laboratoire de Recherche en Bactériologie, Nouméa Cedex, New Caledonia; Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7365
* To whom correspondence should be addressed. Email:
cgoarant{at}pasteur.nc.
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Abstract |
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Antibiotic resistance in Neisseria gonorrhoeae continues to be a major concern in public health. Resistance of N. gonorrhoeae to penicillin G is widespread in most developed countries, which has necessitated a change to newer drugs for treatment of gonococcal infections. Recent reports indicate that resistance to these newer drugs is increasing, highlighting the need for accurate control of recommendations. In some countries or communities, however, N. gonorrhoeae isolates are still susceptible to penicillin, so the use of this antibiotic for single-dose treatments of medically under-resourced patients is beneficial. In order to evaluate the adequacy and sustainability of this treatment approach, we explored the presence and prevalence of chromosomally mediated resistance determinants in N. gonorrhoeae isolates collected from 2005 to 2007 in New Caledonia. We developed two new real-time PCR assays targeting the penB and mtrR determinants, used together with a formerly described duplex assay targeting the penA and ponA determinants. This study provided evidence that neither the most common mtrR determinants nor most resistance-associated penB alleles are currently circulating in New Caledonia, suggesting that penicillin should still be considered as a valuable treatment strategy. Additionally, using our genotyping assay, we observed an unexpected penB genotype in relatively high frequency that was associated witha decreased susceptibility to penicillin (average MIC = 0.15 µg/ml). Sequencing revealed that this genotype corresponded to an A102S mutation in the penB gene. The molecular tools developed in this study can be used successfully for prospective epidemiological monitoring and surveillance of penicillin susceptibility.