To analyze the etiological characteristics of a Nm strain of serogroup W135 isolated from a case of epidemic cerebrospinal meningitis in Chengdu, China in 2024, providing a basis for the public health response to changes in meningococcal disease in this region.

Biochemical identification, mass spectrometry identification, serological identification, antimicrobial susceptibility testing, and whole-genome sequencing were performed on the N. meningitidis strain isolated from the patient’s cerebrospinal fluid and blood. The strain was analyzed using various databases for the purposes of multilocus sequence typing (MLST) and phylogenetic tree analysis. Antimicrobial resistance in the isolated virulence genes was conducted.

The isolated Nm belonged to serogroup W. It showed resistance to Trimethoprim/Sulfamethoxazole, ciprofloxacin, and levofloxacin. It was identified by MLST typing as sequence type (ST) 18719. Phylogenetic analysis indicated that the closest relationship involved an ST-5944 (CC103) strain from serogroup X. The three categories of virulence genes with the highest detection rates were adhesion-related type IV pili, capsular polysaccharide, and lipooligosaccharide. Eight resistance genes associated with efflux pumps from the Major Facilitator Superfamily, Resistance-Nodulation-Division, and ATP-Binding Cassette systems were likewise identified, conferring potential resistance to tetracyclines, macrolides, and carbapenems.

A new pathogenic W serogroup ST-18719 Nm was successfully isolated. This case brings into close focus the diversified trends and characteristics of epidemic cerebrospinal meningitis. Vaccination should be enhanced with vaccines containing W serogroup components in view of strengthening the epidemiological and etiological surveillance of N. meningitidis .