Bedside screening of carbapenem-resistant Enterobacteriaceae using selective agar plates: A low-cost, laboratory-independent approach for rural healthcare facilities.

Abstract

The global surge of carbapenem-resistant Enterobacteriaceae (CRE) poses a critical threat to patient safety in intensive care units (ICUs). In low- and middle-income countries, routine CRE surveillance is often limited by the lack of microbiology laboratory infrastructure and trained personnel in peripheral healthcare facilities, resulting in reliance on empirical broad-spectrum antibiotic therapy and limited capacity to detect silent transmission. This study evaluated the operational feasibility, safety, and phenotypic agreement of a decentralized, laboratory-independent bedside CRE screening protocol using pre-formulated selective chromogenic agar and a low-cost portable incubator. Dual rectal swabs were collected from 220 ICU patients at Viet Tiep Hospital, Vietnam. One sample was processed using standard centralized laboratory procedures as the reference method, while the parallel sample was processed at the bedside by frontline nursing staff, including direct plate inoculation and point-of-care incubation. Diagnostic agreement, inter-reader reliability, procedural contamination, and operational feasibility were assessed. Gastrointestinal CRE carriage was identified in 26 of 220 patients (11.8%), with the KESC group accounting for 76.9% of positive cases. The bedside protocol demonstrated 100% phenotypic concordance with standard laboratory cultures, with 100% sensitivity, specificity, positive predictive value, and negative predictive value. Blinded assessment showed complete inter-reader agreement (κ = 1.0). No environmental cross-contamination was detected on CRE-negative plates (0.0%; 95% CI: 0-4.1%). The decentralized bedside screening model, costing less than US$1 per test, demonstrated high diagnostic agreement and operational feasibility when performed by frontline nursing staff in a non-sterile ICU environment. This approach may provide an affordable alternative for CRE surveillance in resource-limited healthcare facilities where centralized microbiology laboratory infrastructure is unavailable.