Molecular Analysis of Eight American Type Culture Collection Gonococcal Strains by Neisseria gonorrhoeae Multiantigen Sequence Typing and PorB Sequence Typing

BACKGROUND: Molecular epidemiological typing of Neisseria gonorrhoeae is crucial for monitoring the spread of resistant strains. As reference strains can be used for laboratory internal quality control, we genetically characterised the American Type Culture Collection (ATCC) gonococcal strains by Neisseria gonorrhoeae multiantigen sequence typing (NG-MAST) and porB sequence typing using public multilocus sequence typing (PubMLST). METHODS: Eight ATCC gonococcal reference strains (ATCC 19424, ATCC 31426, ATCC 35541, ATCC 43069, ATCC 43070, ATCC 49226, ATCC 49926, and ATCC 49981) from Culti-Loops (Thermo Fisher Scientific, USA) were cultured. After DNA extraction, porB and tbpB were amplified and sequenced. Sequence types (STs) and allele numbers were each determined by NG-MAST (http://www.ng-mast.net) and porB sequence typing using PubMLST (http://pubmlst.org/neisseria/porB/). RESULTS: ATCC 19424 was identified as ST 266 by NG-MAST, and as Allele 946 by PubMLST. ATCC31426 was assigned a novel ST by NG-MAST, and was assigned Allele 958 with 1.2% mismatch by PubMLST. ATCC 35541 was identified as ST 12 by NG-MAST, and as Allele 624 by PubMLST. ATCC 43069 and ATCC 43070 were both identified as ST 681 by NG-MAST, and as Allele 984 by PubMLST. ATCC 49226 was identified as ST 1572 by NG-MAST, and as Allele 2110 by PubMLST. ATCC 49926 and ATCC 49981 were both identified as ST 16496 by NG-MAST, and as Allele 928 by PubMLST. CONCLUSIONS: The ST data obtained for ATCC gonococcal reference strains by NG-MAST and porB sequence typing using PubMLST can be used for quality assurance of molecular epidemiological typing in clinical microbiological laboratories.

Antimicrobial Resistance and Molecular Epidemiologic Characteristics of Neisseria gonorrhoeae Isolated from Korea in 2013 / 대한임상미생물학회지

BACKGROUND: Antimicrobial resistance of Neisseria gonorrhoeae has become a serious problem worldwide, and ceftriaxone non-susceptible isolates have been recently reported from Japan and Europe. In this study, we evaluated the antimicrobial susceptibilities and molecular epidemiological characteristics of isolates from Korea in 2013. METHODS: Sixty strains of N. gonorrhoeae were collected from Korean patients and prostitutes. Antimicrobial susceptibility was tested by the agar dilution and disk diffusion methods. N. gonorrhoeae multi-antigen sequence typing (NG-MAST) was performed in order to determine the molecular epidemiologic relatedness. RESULTS: All of isolates were non-susceptible to penicillin G and tetracycline, and the rate of ciprofloxacin-resistant isolates was 95% in 2013. The MICs of ceftriaxone were within the susceptible range for all isolates, but one isolate non-susceptible to cefixime (MIC=0.5 microg/mL) was encountered. The isolates with decreased susceptibility (MIC< or =0.12 microg/mL) to cefixime or ceftriaxone accounted for 10% and 14% of the isolates tested, respectively. In NG-MAST analysis, 40 different STs were encountered among the 59 isolates. Isolates that belonged to tbpB110 showed higher cefixime and ceftriaxone MICs (0.12-0.5 microg/mL) as well as cefixime resistance. CONCLUSION: Most of the N. gonorrhoeae isolates showed susceptibility to spectinomycin and cephalosporins. Due to the emergence of isolates that are non-susceptible to cefixime and the prevalence of isolates with the tbpB110 allele belonging to ST1407, which cause cefixime and ceftriaxone treatment failure in successful global clones of N. gonorrhoeae, a continuous nationwide antimicrobial surveillance program is required to monitor the emergence of cephalosporin resistance in N. gonorrhoeae.