Molecular characteristics and antimicrobial susceptibility of penicillinase-producing Neisseria gonorrhoeae isolates in Fukuoka, Japan, 1996–2018. (September 2021) - Tanaka, Masatoshi
Highlights: The bla TEM-135 allele is considered a possible direct precursor of an ESBL in PPNG. Proportion of PPNG with bla TEM-135 -carrying Toronto/Rio plasmid increased between 1996–2006 and 2007–2018. Increase in PPNG with TEM-135 was associated with spread of genogroup G15576. Proportion of PPNG with bla TEM-1 -carrying African plasmid decreased between 1996–2006 and 2007–2018. PPNG less susceptible to cefixime had the bla TEM-1 allele and various penA alleles. ABSTRACT: 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 β-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 β-lactamase (ESBL).