Microbial contamination of manually reprocessed, ready to use ECG lead wire in intensive care units

A number of studies have shown that non-critical medical devices can be contaminated with pathogens, including those resistant to antibiotics and thus become a potential vector for transmission. Electrocardiography (ECG) lead wire are non-critical medical device which are always attached on patient skin during their stay in intensive care unit (ICU). In view of the patient's critical conditions and exposure to invasive procedures, identification and prevention of possible risks are important to prevent infection in ICUs.

The objective of this study was to determine the presence of bacterial and fungal contamination on cleaned and disinfected reusable ECG lead wires in intensive care units in a hospital.

A total of 408 cleaned ECG lead wires from 93 bed-side ECG devices and 43 ECG lead wires from 5 portable ECG devices from 4 intensive care units (ICUs) and 1 post-anaesthesia care unit (PACU) were sampled. ECG lead wires were stirred in 0.89% NaCl with added neutralizer for 30 seconds. Samples of the solutions were cultured directly on blood agar. The remaining solution was cultured on blood agar after sterile filtration. The number of colony forming units (CFUs) was counted and the microorganisms were identified.

More than half of examined ECG lead wires (n=232; 51.4%) were contaminated with >30 CFUs/mL sample of bacteria or with risk pathogens. Gram-positive bacteria were the most frequently isolated organisms; particularly, coagulase negative staphylococci (96%) and aerobic spore forming bacteria (71.2%). Compared to ICUs, PACU had significantly lower proportion of contaminated ECG lead wires (p<0.05). The proportion of contaminated ECG lead wires, as well as mean number of cfus per ECG lead wire, was also significantly lower among multi-wire ECG leads compared to single-wire ECG leads.

Manually cleaned ECG lead wires may serve as a vector for transmission of nosocomial pathogens. The current reprocessing technique for ECG lead wires needs to be improved.