Acetic acid as a decontamination method for ICU sink drains colonized by carbapenemase-producing Enterobacteriaceae and its effect on CPE infections

Abstract

Carbapenemase-producing Enterobacteriaceae (CPE) are emerging pathogens representing a major concern for public health. In Belgium, the OXA-48 carbapenemase resistance gene is identified most frequently. Sink drains in intensive care units (ICUs) are known to be colonized by Gram-negative bacilli. A correlation between environmental contamination and CPE infections in ICUs has been established. A long-term CPE epidemic in a local ICU proved difficult to control. A variety of CPE strains, all carrying the OXA-48 resistance gene, were isolated from almost all sinks in patient rooms in the ICU. Decontamination of the sinks with 250 mL 25% acetic acid three times weekly was implemented. Sink drain colonization was followed up for six months thereafter. Both the number of CPE-colonized sinks and the number of patients colonized or infected with CPE decreased drastically, to the extent that the epidemic was considered to be eradicated. In-vitro growth of all isolates was inhibited by a concentration of acetic acid equal to or smaller than that used for decontamination. Epidemiological analysis demonstrated a positive and significant relationship between contaminated sinks and CPE acquisition of patients admitted to ICU rooms, indicating the importance of contaminated sinks as the environmental reservoir of the epidemic. Decontamination of sink drains with acetic acid is a valuable alternative to other methods, such as heated sinks and water-free care, especially when other options are not feasible in the short term. Acetic acid is cheap, widely available, effective and manageable from a safety and technical point of view.