Plasmid-Mediated Penicillin and Tetracycline Resistance Among Neisseria gonorrhoeae Isolates in South Africa: Prevalence, Detection and Typing Using a Novel Molecular Assay

• Published in: Sexually transmitted diseases 2011-04, Vol.38 (4), p.329-333
• Main Authors: Fayemiwo, Samuel A., Müller, Etienne E., Gumede, Lindy, Lewis, David A.
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - pharmacology; Bacterial diseases; Bacterial diseases of the genital system; beta-Lactamases - genetics; Biological and medical sciences; DNA, Bacterial - genetics; Drug resistance; Epidemiology. Vaccinations; General aspects; Gonorrhea - drug therapy; Gonorrhea - microbiology; Gram-negative bacteria; Human bacterial diseases; Human infectious diseases. Experimental studies and models; Humans; Infectious diseases; Male; Medical sciences; Medical treatment; Microbial Sensitivity Tests; Molecular Typing; Neisseria gonorrhoeae - drug effects; Neisseria gonorrhoeae - genetics; Neisseria gonorrhoeae - isolation & purification; Original Study; Penicillin; Penicillin Resistance - genetics; Penicillins - pharmacology; Plasmids; Polymerase chain reaction; Polymerase Chain Reaction - methods; Prevalence; R Factors - genetics; South Africa; Tetracycline - pharmacology; Tetracycline Resistance - genetics; Urethra - microbiology
• ISSN: 0148-5717; 1537-4521
• DOI: 10.1097/OLQ.0b013e3181fc695a

Background: To detect and type plasmids responsible for penicillin and tetracycline resistance in Neisseria gonorrhoeae isolates using a novel duplex polymerase chain reaction (PCR) assay. Methods: A duplex PCR assay, to detect and type penicillinase-producing N. gonorrhoeae (PPNG), and plasmid-mediated tetracycline resistant N. gonorrhoeae (TRNG), was developed on the basis of published single assays. Gonococcal Isolate Surveillance Project control strains were used in assay development and then 209 consecutive N. gonorrhoeae isolates, collected from men with urethral discharge in 2008, were tested. Controls included Asia, Africa, and Toronto β-lactamase plasmids, as well as American and Dutch TRNG plasmids. PCR amplicons were detected using an Agilent 2100 Bioanalyzer. Minimum inhibitory concentrations (MIC) were determined with E tests. Penicillinase production was detected using Nitrocefin solution. Results: Among 209 gonococcal isolates, 54 (25.8%) PPNG and 154 (73.3%) TRNG were detected. The MIC₅₀ and MIC₉₀ values were determined for penicillin (0.19 and 32 mg/L) and tetracycline (6 and 16 mg/L). The assay detected the Africa-type (35.2%), the Toronto-type (44.4%), and a new type (20.3%) of ß-lactamase plasmid. The American-type TRNG plasmid was 3-fold more frequent as compared with the Dutch-type. Although there was no overall association between the detection of PPNG and TRNG plasmids, only American type TRNG contained β-lactamase-encoding plasmids (P < 0.0001). Conclusions: The prevalence of plasmid-mediated resistance to tetracycline, and to a lesser extent penicillin, is high and neither drug is likely to have any future role in the treatment of gonorrhoea in South Africa. A novel β-lactamase plasmid was detected during the study and requires further characterization.