# High prevalence and emerging cephalosporin resistance of penicillinase-producing Neisseria gonorrhoeae in Meizhou, China (2022–2024)

## TL;DR

This study found a high rate of penicillin-resistant gonorrhea in Meizhou, China, with some strains also showing resistance to cephalosporin antibiotics.

## Contribution

The study reports the first detailed molecular and epidemiological analysis of PPNG in Meizhou, China, including emerging cephalosporin resistance patterns.

## Key findings

- 78.2% of isolates were penicillinase-producing Neisseria gonorrhoeae (PPNG), primarily carrying African-type plasmids.
- 17.7% of PPNG strains showed reduced cephalosporin susceptibility, with some harboring mosaic PBP2 patterns.
- Phylogenetic analysis linked blaTEM−135 strains to epidemic strains in Japan, Thailand, and Chinese cities.

## Abstract

The global spread of penicillinase-producing Neisseria gonorrhoeae (PPNG) has rendered penicillin-based regimens largely ineffective, and emerging cephalosporin-resistance patterns continue to challenge therapeutic strategies. However, epidemiological surveillance data from resource-limited regions of China remain scarce. This study aimed to determine the prevalence, molecular epidemiology and cephalosporin susceptibility of PPNG isolates in Meizhou, China.

Neisseria gonorrhoeae isolates were collected from Meizhou People’s Hospital between 2022 and 2024. Antimicrobial susceptibility to penicillin, ceftriaxone, and cefixime was determined using the broth microdilution method, with PPNG identified by the nitrocefin test. Plasmid types were detected by multiplex PCR, while blaTEM genes were analyzed using Mismatch Amplification Mutation Analysis (MAMA). Full-length sequencing of the penA gene was performed for ceftriaxone/cefixime-resistant isolates. All PPNG strains underwent molecular typing via Neisseria gonorrhoeae multiantigen sequence typing (NG-MAST) with phylogenetic tree construction, while blaTEM−135-carring strains were further analyzed through porB-based phylogenetic reconstruction.

A total of 101 Neisseria gonorrhoeae isolates were collected. Among these, 78.2% (79/101) were PPNG, carrying African-type (92.4%, 73/79) or Asian-type (7.6%, 6/79) plasmids; within the PPNG group, 94.9% (75/79) harbored blaTEM−1 and 5.1% (4/79) blaTEM−135. African-type blaTEM−1-positive PPNG isolates showed cephalosporin-resistance rates similar to those of non-PPNG isolates for both ceftriaxone (12.3% vs. 9.1%; p = 1.00) and cefixime (20.5% vs. 13.6%; p = 0.76), with no statistically significant difference. Overall, 17.7% of the PPNG strains exhibited reduced cephalosporin susceptibility (MIC > 0.125 mg/L) and harbored either mosaic or non-mosaic PBP2 patterns. NG-MAST identified 43 sequence types, with ST17748 being the predominant ST. Phylogenetic analysis revealed a dispersed distribution of Asian-type blaTEM−135 strains, and blaTEM−135-positive isolates clustered closely with epidemic strains from Japan, Thailand, and Chinese cities.

The high prevalence of PPNG and emerging cephalosporin resistance, including blaTEM−135 variants with potential ESBL activity, highlights the need to strengthen regional surveillance and develop appropriate control measures for resistant gonorrhea in this area.

Not applicable.