Work

Assessing cross-transmission of Gram-negative bacteria in the intensive care unit: a prospective comparison of IR-Biotyper and core-genome multi-locus sequence typing

Year: 2026

Type: article

Abstract: BACKGROUND: Healthcare-associated infections are a major concern in intensive care units (ICUs), where early detection of transmission cluster is critical. Whole-genome sequencing remains the reference method for outbreak investigation but is limited by cost and turnaround time. The IR Biotyper (IRBT) provides rapid phenotypic clustering, but its core-genome-level performance remains insufficiently evaluated. AIM: This study evaluated the analytical performance of IRBT at the core-genome level for detecting clinically relevant Gram-negative bacterial cross-transmission in ICUs. METHODS: In this prospective single-centre study, all clinical, screening and environmental isolates of Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae complex and Stenotrophomonas maltophilia that were recovered in a 36-bed ICU over seven months were analysed. Transmission clusters were assessed using core-genome multi-locus sequence typing (cgMLST). IRBT spectral distances were compared with allelic distances from cgMLST. Diagnostic performance metrics were calculated using both manufacturer-recommended (Bruker) and automated IRBT thresholds. FINDINGS: Among 283 isolates from 135 patients, cgMLST identified 23 transmission cluster events. Using Bruker thresholds, IRBT achieved high species-specific specificity (ranging from 0.91 to 0.99) and negative predictive values (NPVs: ≥0.94) across all species. E. cloacae complex showed near-perfect performance (sensitivity: 0.94, specificity: 0.99 and NPV: 0.998), while K. pneumoniae and E. coli demonstrated strong concordance (sensitivity ≥0.81). Lower sensitivity was observed for P. aeruginosa (0.77) and S. maltophilia (0.70). Automated thresholds improved specificity and positive predictive value but reduced sensitivity. Receiver operating characteristic curves confirmed high discriminatory power (area under the curve value: 0.899-0.999). CONCLUSIONS: IRBT provides rapid, species-specific phenotypic clustering for ICU Gram-negative bacterial transmission cluster surveillance.

Source: Journal of Hospital Infection

DOI: 10.1016/j.jhin.2026.01.004