Security swipe cards and scanners are a potential reservoir for hospital-acquired infection

Hospital-acquired infections complicate 10% of hospital admissions resulting in increased morbidity, mortality and cost to hospitals. Most hospitals issue doctors with plastic swipe cards that function as electronic keys to access clinical areas. The card is handled many times a day, often before direct patient contact. The aim of this study was to determine if swipe cards harbour potentially harmful bacteria.

On a single day, doctors working in the surgical directorate completed a questionnaire to determine their pattern of swipe card use. Cards were inoculated onto agar plates and incubated for 48 h under standard laboratory conditions, following which the number of colony forming units (CFUs) cultured from each card was determined. Representative colonies were sampled and sub-cultured for staphlococcal, enterococcal, coliform and pseudomonad species. Isolated bacterial pathogens were tested for antimicrobial sensitivity. Swipe-card scanners were swabbed for microbiological culture on the same day.

All cards were colonised with environmental bacteria (mean, 73 CFU). Of cards, 21% were contaminated with pathogenic bacteria including Staphylococcus aureus (5.1%), Pseudomonas putida (2.6%), and coliform species (12.8%). The pattern of card use did not significantly affect the amount of bacterial contamination, but infrequent use of the card and keeping the card in a pocket or wallet was associated with higher levels of contamination. Environmental bacteria were cultured from 88% of card scanners, the highest counts coming from scanners in main theatres and the day-surgery unit.

Doctors' swipe cards are contaminated with, and may therefore be a reservoir for, pathogenic bacteria implicated in hospital-acquired infection.