Characteristics of Neisseria meningitidis isolated from patients with urogenital infection in a region of China.

Abstract

Background: Neisseria meningitidis (Nm), traditionally recognized as a nasopharyngeal commensal causing invasive meningococcal disease (IMD), has recently emerged as an etiological agent of urethritis worldwide, with sporadic urogenital cases in China raising epidemiological concerns.

Methods: Three urogenital Nm isolates were characterized to investigate their evolutionary features and transmission patterns. Through comprehensive laboratory characterization encompassing culture identification (Gram staining, oxidase testing, MALDI-TOF MS), antimicrobial susceptibility profiling, whole-genome sequencing, and functional colonization assays on urethral epithelial cells under nitrite-supplemented microaerobic conditions, three multidrug-resistant Nm isolates were identified.

Results: All isolates demonstrated resistance to penicillin and sulfamethoxazole/trimethoprim, with isolate 24-SHSP-NM2 exhibiting additional ciprofloxacin resistance. The resistance was attributed to penA variants, mtrR promoter mutations, and gyrA substitutions. Phylogenetically, one isolate clustered with Japanese ST-11,026 strains and 2 clustered with Australian ST-1466 strains. Genomic characterization identified complete denitrification operons (aniA-norB) in all three isolates, which enable nitrite-enhanced epithelial colonization. ST-1466 isolates showed meningococcal B (MenB) vaccine component FHbp antigenic homology through FHbp variant 1.1.

Conclusions: These findings collectively demonstrate the convergent evolution of urogenital tropism, antimicrobial resistance (AMR) emergence, and metabolic adaptation to genitourinary microenvironments, underscoring the threat of genitourinary Nm infections. The study highlights the critical need to enhance molecular surveillance, implement rapid AMR screening, and prioritize MenB vaccination strategies in high-risk populations.