Elizabethkingia Species as an Emerging Pathogen: A Comprehensive Review of Clinical and Microbiological Evidence

Elizabethkingia species are rare but increasingly recognised Gram-negative pathogens linked to healthcare-associated transmission, intrinsic multidrug resistance, and severe infection in vulnerable hosts. We performed a comprehensive review of human Elizabethkingia infections by systematically searching PubMed on 18 October 2025 and included English-language case reports, case series, and outbreak investigations; species were analysed as reported (legacy nomenclature retained), and adults were defined as ≥18 years. In total, 374 studies were included (300 case reports, 41 case series, 33 outbreak investigations). Adult infections were predominantly healthcare-related, affected older adults with substantial comorbidities and most often presented as bacteraemia or sepsis and pneumonia; crude mortality in adult case reports was 32.8%. Paediatric disease was concentrated in neonates and Neonatal Intensive Care Unit (NICU) settings, with meningitis and bloodstream infection predominating; crude mortality in paediatric case reports was 23.3%, and neurological sequelae were frequently reported among survivors. Across studies, isolates showed broad resistance to β-lactams and near-universal resistance to carbapenems, with variable activity to fluoroquinolones and trimethoprim-sulfamethoxazole and more consistent in vitro activity to minocycline. Species misidentification (notably Elizabethkingia anophelis as Elizabethkingia meningoseptica) and heterogeneous susceptibility testing limited comparability. Outbreak investigations repeatedly implicated water-associated reservoirs and reusable equipment, underscoring the need for improved diagnostics, susceptibility-guided therapy and water-focused infection prevention.