Stewarding the hospital sink drain: a narrative review of practical approaches for controlling gram negative pathogens in low- and middle-income countries.

In low- and middle-income countries (LMICs), gram-negative bacteria cause over half of intensive care unit (ICU) infections, with up to 50% mortality associated with multidrug-resistant (MDR) strains. Hospital sink drains are increasingly recognized as reservoirs for MDR organisms and are well-documented sources for nosocomial infections, yet effective and sustainable decontamination strategies-particularly for resource-limited facilities-remain elusive. This narrative review synthesizes evidence on sinks as pathogen reservoirs, evaluates limitations of existing remediation approaches, presents pilot data from our tertiary hospital in Botswana, and outlines research priorities for LMICs. We identify five dimensions that complicate control of gram-negative pathogens in sink drains: (1) poor visibility of drain interiors limiting awareness of biofilm growth extent; (2) nutrient inputs from non-hand-hygiene uses that can encourage microbial growth; (3) design barriers to cleaning and disinfection; (4) inconsistent pathogen detection methods; and (5) uncertainty about optimal regimens for cleaning and disinfection. We share data from pilot studies assessing treatment interventions for neonatal ICU sinks with high baseline contamination-including periodic addition of boiling water, sodium hypochlorite, and a commercial probiotic cleaner. Carbapenem-resistant Enterobacterales growth was suppressed by treatment with boiling water and sodium hypochlorite, but the highest prevalence of extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) and Acinetobacter spp. was observed for sinks treated with sodium hypochlorite; probiotic cleaning was associated with the lowest ESBL-E prevalence. Findings from our literature review and pilot studies collectively support the need for a framework for hospital sink-drain stewardship that shifts away from routine chemical disinfectants and toward effective thermal or microbial strategies (e.g., probiotics, bacteriophages) that could reduce pathogen burden without selecting for more virulent or drug-resistant strains. Future work should define concentrations/regimens, safety precautions, and pathogen monitoring strategies for these approaches and embed them within sink-drain stewardship frameworks suitable to LMIC settings.