Evolutionary adaptations of a pediatric pathogen: low-inflammatory and high-resistance phenotypes in the emerging Salmonella typhimurium monophasic variant 1,4,[5],12:i:-

Abstract

S .1,4,[5],12:i:- poses a growing global health threat, particularly endangering infants and young children. Characterized by increasing prevalence, multidrug resistance, and diagnostic challenges, this variant demonstrates milder inflammatory responses yet stronger antibiotic resistance than traditional S. typhimurium in pediatric infections. Crucially, we identified its unique “low-inflammation, high-resistance” evolutionary strategy associated with anti-inflammatory gene gogB and resistance plasmid IncHI2/IncHI2A. The stealthy evolutionary adaptation provides novel insights into this variant’s global dominance, while offering critical guidance for improving clinical management and formulating targeted public health measures to protect vulnerable pediatric populations against this cunning pathogen.