Prevalence of porA pseudogene deletion among Neisseria gonorrhoeae isolates referred to the UK's Gonococcal Resistance to Antimicrobials Surveillance Program.

porA pseudogene-negative Neisseria gonorrhoeae isolates produce false-negative results when examined by polymerase chain reaction (PCR) with porA pseudogene targets. In the present study, 533 representative gonococcal isolates received in 2011 via the Gonococcal Resistance to Antimicrobials Surveillance Program were examined to determine the prevalence of porA-negative isolates. Less than 0.4% (2/533) of isolates were found to be reproducibly negative with the porA real-time PCR but were confirmed as N. gonorrhoeae with molecular, biochemical and immunological confirmatory tests. Sequencing revealed both isolates contained the Neisseria meningitidis porA gene. Low prevalence indicates that although these isolates do not present a major public health problem, microbiologists should remain vigilant.

Genetic diversity of blaTEM alleles, antimicrobial susceptibility and molecular epidemiological characteristics of penicillinase-producing Neisseria gonorrhoeae from England and Wales.

OBJECTIVES: The objective of this study was to investigate the genetic diversity of blaTEM alleles, antimicrobial susceptibility and molecular epidemiological characteristics of penicillinase-producing Neisseria gonorrhoeae (PPNG) isolates collected in 2012 from England and Wales. METHODS: PPNG isolates were from the 2012 Gonococcal Resistance to Antimicrobial Surveillance Programme (GRASP). Their susceptibility to seven antimicrobials was determined using agar dilution methodology. ß-Lactamase production was detected using a nitrocefin test. ß-Lactamase plasmid types were determined and blaTEM genes were sequenced. Isolates were also typed by N. gonorrhoeae multi-antigen sequence typing (NG-MAST). RESULTS: Seventy-three PPNG isolates were identified in the 2012 GRASP collection (4.6%, 73/1603). Three different blaTEM alleles were identified, encoding three TEM amino acid sequences: TEM-1 (53%), TEM-1 with a P14S substitution (19%) and TEM-135 (27%). The blaTEM-135 allele was present in nine different NG-MAST types and was found mostly on Asian (60%) and Toronto/Rio (35%) plasmids. By contrast, most TEM-1-encoding plasmids were African (98%). All the TEM-135 isolates displayed high-level ciprofloxacin and tetracycline resistance. CONCLUSIONS: The high proportion of blaTEM-135 alleles (27%) demonstrates that this variant is circulating within several gonococcal lineages. Only a single specific mutation near the ß-lactamase active site could result in TEM-135 evolving into an ESBL. This is concerning particularly because the TEM-135 isolates were associated with high-level ciprofloxacin and tetracycline resistance. It is encouraging that no further TEM alleles were detected in this gonococcal population; however, vigilance is vital as an ESBL in N. gonorrhoeae would render the last remaining option for monotherapy, ceftriaxone, useless.

Is the tide turning again for cephalosporin resistance in Neisseria gonorrhoeae in Europe? Results from the 2013 European surveillance.

BACKGROUND: The emerging resistance to the extended-spectrum cephalosporins (ESCs) in Neisseria gonorrhoeae together with increasing incidence of gonorrhoea cases in many countries have been global public health concerns. However, in recent years the levels of ESC resistance have decreased in several regions worldwide. We describe the European Gonococcal Antimicrobial Surveillance Programme (Euro-GASP) data from 2013, and compare them to corresponding data from 2009-2012. METHODS: During 2013, N. gonorrhoeae isolates from 21 participating countries were examined. Antimicrobial susceptibility testing (Etest or agar dilution) was performed for cefixime, ceftriaxone, ciprofloxacin, azithromycin, spectinomycin and gentamicin. Statistical analyses were performed to identify significant changes in resistance between years and to investigate associations between patients with resistant gonococcal isolates and collected epidemiological variables. RESULTS: In total, 93 (4.7 %) of 1994 isolates displayed resistance to cefixime, representing an increase compared to the 3.9 % detected in 2012 (p = 0.23). Cefixime resistance was detected in 13 (61.9 %) of the 21 countries. Cefixime resistance among men who have sex with men was only 1.2 %, compared to 5.6 % and 6.1 % in females and male heterosexuals, respectively. The univariate analysis confirmed that isolates resistant to cefixime were more likely to be from females (OR 4.87, p < 0.01) or male heterosexuals (OR 5.32, p < 0.01). Seven (0.4 %) isolates displayed ceftriaxone resistance (in addition to cefixime resistance) compared to three and 10 isolates in 2012 and 2011, respectively. All 93 isolates with cefixime resistance were additionally resistant to ciprofloxacin and 16 (17.2 %) were also resistant to azithromycin. Among all tested isolates (n = 1994), the ciprofloxacin resistance level (52.9 %) was higher than in 2012 (50.1 %; p = 0.08), and azithromycin resistance (5.4 %) increased since 2012 (4.5 %; p = 0.16). CONCLUSIONS: In 2013, the ESC resistance was again slightly increasing in Europe. This emphasises the importance of implementing the actions outlined in the European and additional response plans, particularly activities strengthening the surveillance of antimicrobial resistance. Ceftriaxone combined with azithromycin remains a satisfactory option for the first-line treatment of gonorrhoea. However novel antimicrobials (new derivatives of previously developed antimicrobials or newly developed antimicrobials) for effective monotherapy or at least inclusion in new dual antimicrobial therapy regimens (combined with previously developed antimicrobials or novel antimicrobials) will likely be required.