Molecular characteristics and antimicrobial susceptibility of penicillinase-producing Neisseria gonorrhoeae isolates in Fukuoka, Japan, 1996-2018

Objectives: The objective of this study was to investigate the molecular characteristics and antimicrobial susceptibility of penicillinase-producing Neisseria gonorrhoeae (PPNG) isolates collected in Fukuoka, Japan, from 1996-2018. Methods: Antimicrobial susceptibility to seven antibiotics was determined by the agar dilution method. Molecular characteristics were determined by Sanger sequencing of the bla(TEM) allele, plasmid typing and N. gonorrhoeae multiantigen sequence typing (NG-MAST). Furthermore, full sequences of the penA gene, encoding penicillin-binding protein 2 (PBP2), of PPNG isolates with reduced susceptibility to cefixime were analysed. Results: Among 50 PPNG isolates, 17 and 33 were collected during 1996-2006 and 2007-2018, respectively. In 1996-2006, bla(TEM-1) in African plasmid was most frequent (64.7%), followed by bla (TEM-1) in Asian plasmid (29.4%) and bla(TEM-135) in Toronto/Rio plasmid (5.9%). In 2007-2018, bla(TEM-135) in Toronto/Rio plasmid was predominant (54.5%), followed by bla(TEM-1) in African plasmid (36.4%) and bla (TEM-135) in Asian plasmid (6.1%). Among isolates with the bla(TEM-135)-carrying Toronto/Rio plasmid in 2007-2018, a novel genogroup G15576 was predominant (66.7%). Isolates with the TEM-135 beta-lactamase were more resistant to ciprofloxacin but were more susceptible to ceftriaxone and tetracycline than isolates with TEM-1. Seven PPNG isolates less susceptible to cefixime possessed the plasmidic bla(TEM-1) allele and had mosaic or non-mosaic alterations within PBP2. Conclusion: The proportion of PPNG with the bla(TEM135)-carrying Toronto/Rio plasmid increased during the last 12 years. The increase in PPNG carrying the bla(TEM-135) allele is of particular concern as it is considered a possible direct precursor of an extended-spectrum beta-lactamase (ESBL). (C) 2021 The Author(s). Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy.