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

## TL;DR

Elizabethkingia species are rare but dangerous bacteria causing severe infections in vulnerable patients, with high mortality rates and resistance to many antibiotics.

## Contribution

This paper provides a comprehensive review of Elizabethkingia infections, highlighting clinical patterns, resistance profiles, and challenges in diagnosis and treatment.

## Key findings

- Adult Elizabethkingia infections are often healthcare-associated, with high mortality and common presentations of bacteraemia or sepsis.
- Neonatal infections are frequently associated with NICUs and meningitis, with significant mortality and neurological complications.
- Elizabethkingia isolates show widespread resistance to β-lactams and carbapenems, with variable susceptibility to other antibiotics.

## Abstract

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.