Emergence of Neisseria meningitidis ST-3587 harbouring bla ROB-1 and exhibiting dual resistance to penicillin and ciprofloxacin, Spain, 2024

BACKGROUND Dual penicillin- and ciprofloxacin-resistant Neisseria meningitidis causing invasive meningococcal disease (IMD) have recently emerged in association with sequence type (ST) 3587, harbouring ROB-1 β-lactamase ( bla ROB-1 ) and a mutated DNA gyrase ( gyrA ). These strains pose a threat to current antimicrobial treatment and prophylaxis. AIM We aimed to characterise the first dual-resistant N. meningitidis ST-3587 isolates harbouring bla ROB-1 and a mutated gyrA identified in Spain. METHODS Three N. meningitidis isolates encoding bla ROB-1 were identified in 2024. They were characterised by whole genome sequencing to determine capsular genogroups, ST and genetic antimicrobial resistance markers. Dated phylogenetic analysis was performed alongside global ST-3587 strains. RESULTS The three bla ROB-1 -encoding isolates belonged to ST-3587, genogroup Y, harboured a T91I mutation in gyrA and showed resistance to penicillin and ciprofloxacin. These isolates were obtained from urethral, oropharyngeal and blood samples, each from a different patient. According to the dated phylogenetic analysis of ST-3587 and the presence of bla ROB-1 , two clades were defined: clade I and clade II. Within clade II, subclade II.I was identified, comprising isolates which, in addition to bla ROB-1 , carried the T91I mutation in gyrA . This subclade included the three Spanish isolates, which exhibited close genetic relatedness. CONCLUSION This study documents the emergence of N. meningitidis ST-3587 with dual resistance in Europe, including a documented urogenital infection by this lineage. Continued surveillance of antimicrobial resistance in N. meningitidis , including non-invasive cases, is crucial for timely public health responses and effective IMD prevention strategies.