Poster Presentation 25th International Pathogenic Neisseria Conference 2026

Persistence of Neisseria gonorrhoeae isolates with reduced susceptibility to cefixime carrying mosaic penA allele XXXIV in Iquitos, Peru (#008)

Gilda Bocco 1 , Reuel Sandy 1 , Anjali Sapre 2 , Melissa Martin 2 , Ann E Jerse 3 , Paul Rios 4 , Adriana Le Van 1
  1. Henry Jackson Foundation - Uniform Services University of the Health Sciences, Bethesda, MD, United States
  2. Multidrug Resistant Organism Repository and Surveillance Network, Walter Reed Army Institute of Research, Silver Spring, MD
  3. Uniform Services University of the Health Sciences, Bethesda, MD
  4. US Naval Medical Research Unit SOUTH, Lima, Peru

Background: The threat of antibiotic resistance is a major concern when treating Neisseria gonorrhoeae (Ng). Ng’s current recommended treatment is a single injection of ceftriaxone or dual therapy with cephalosporin and azithromycin. Since extended-spectrum cephalosporins (ESCs) are one of the last successful treatments available for Ng infections, surveillance for resistant Ng strains and antibiotic resistance alleles is critical. Mutations in the penA gene encoding the penicillin-binding protein 2 have been shown to reduce cephalosporin susceptibility. Surveillance for penA alleles can explain changes in ESC resistance, as well as track specific mutations and how they are maintained within populations.

Methods: Urogenital Ng isolates (n = 251) were collected from Peru between 2012 and 2024. Isolates were tested for susceptibility to seven different antibiotics using ETEST. Whole genome sequencing was performed to define the prevalence of specific antimicrobial resistance determinants.

Results: In total, fourteen penA alleles were identified and only two mosaic alleles, 34.001 (n=4) and 34.007 (n=41), belonged to Type XXXIV (n=45). These isolates showed reduced susceptibility to cefixime MIC ≥0.125 μg/mL). Several multi-locus sequences typing (MLST) types were identified among the 251 (?) isolates. Before 2020, Peruvian isolates harboring the mosaic penA XXXIV allele belonged to the ST 1901 and ST 15242 but afterwards, ST 8123 and ST 1583 were the predominant types. Since 2022 the frequency of the mosaic penA XXXIV allele increased from 58% to 72%. Most of these isolates did not carry the ponA mutation L421P; only the MLST 1901 types carried this mutation.

Conclusion: The persistence of these penA mutations is the key to understanding how cephalosporin resistance is emerging and learning about new mechanisms to overcome the concern of antibiotic resistance that could help develop potential new antibiotic targets. MLST types 8123 and 1583 have been dominating the penA allele XXXIV in Iquitos, Peru.