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Increasingly antimicrobial resistant Neisseria gonorrhoeae added to the NCTC & World Health Organisation reference strain panel

NCTC 14208 carries an allele of the penA gene which confers high-level ceftriaxone resistance, and A2059G mutations in all four copies of its 23S rRNA genes which confers high-level azithromycin resistance. Two other high-level ceftriaxone and high-level azithromycin resistant Neisseria gonorrhoeae isolates have since been reported in Australia, where comparison of whole genome sequence data revealed that both isolates share the same penA allele and A2059G mutation(s)1. NCTC 14208 has also been used to contextualise a high-level ceftriaxone resistant and intermediately azithromycin resistant strain isolated in Ireland in August 2018, which shares the penA allele but not the A2059G mutation(s)2.

Isolates such as these continue to raise concern about the spread and incidence of multi-drug resistance in Neisseria gonorrhoeae and reinforce the need for effective diagnostics, surveillance and treatment options.

NCTC 14208 has been added to the World Health Organisation (WHO) panel of Neisseria gonorrhoeae strains for inter-laboratory antimicrobial susceptibility testing quality assurance as WHO Q, complementing NCTC 13477-84 (WHO F, G, K, L, M, N, O, P) and NCTC 13817-22 (WHO U, V, W, X, Y, Z). The remit of this panel is to enhance the efficacy and quality assurance of the WHO global Gonococcal Antimicrobial Surveillance Programme (GASP) and other GASP initiatives world-wide by making available a standardised set of control strains for use in laboratory investigation. Effective surveillance of antimicrobial resistance and its spread (in Neisseria gonorrhoeae and other species) is necessary to help inform relevant research, epidemiological studies (as NCTC 14208 has in the examples above), development of diagnostics and treatment guidelines.

NCTC 13477-84 and NCTC 13817-22 exhibit a range of AMR phenotypes and are comprehensively described in Unemo et al. 20163, where MIC data, serogroup, serovar, MLST sequence type, key mutations and more are presented, described and discussed for all 14 strains. Whole genome sequence data for all 14 strains has been deposited in the ENA under BioProject accession no. PRJEB14020. 

NCTC 14208 has been similarly characterised by Eyre et al. 20184, with whole genome sequence data also available via ENA under BioProject accession no. PRJEB26560.

A PCR for the detection and surveillance of the penA allele conferring high-level ceftriaxone resistance1 is described by Whiley, D. M., et al. (2018).



  1. Jennison AV et al. Genetic relatedness of ceftriaxone-resistant and high-level azithromycin resistant Neisseria gonorrhoeae cases, United Kingdom and Australia, February to April 2018. Euro Surveill. 2019 Feb;24(8). [PMID 30808445].

  2. Golparian D. et al. Multidrug-resistant Neisseria gonorrhoeae isolate, belonging to the internationally spreading Japanese FC428 clone, with ceftriaxone resistance and intermediate resistance to azithromycin, Ireland, August 2018. Euro Surveill. 2018 Nov 22; 23(47). [PMID 30482267]

  3. Magnus Unemo et al. The novel 2016 WHO Neisseria gonorrhoeae reference strains for global quality assurance of laboratory investigations: phenotypic, genetic and reference genome characterization. J Antimicrob Chemother. 2016 Nov;71(11):3096-3108. [PMID 27432602]

  4. David W Eyre et al. Gonorrhoea treatment failure caused by a Neisseria gonorrhoeae strain with combined ceftriaxone and high-level azithromycin resistance, England, February 2018. Euro Surveill. 2018 Jul 5; 23(27). [PMID 29991383


Written By Jake Turnbull (twitter: @HotchPotchJake)

January 2020