Contamination of X-Ray Equipment and Accessories with Nosocomial Bacteria and the Effectiveness of Common Disinfecting Agents

Radiography plays a very important role in medical diagnosis but the equipment and accessories used bear a considerable risk of harbouring nosocomial bacteria which may complicate patient’s original condition. The aim of the study was to identify the nosocomial bacteria commonly found on x-ray equipment and accessories in this locality and assess the effectiveness of some common chemical disinfectants used in x-ray units. Swab samples were collected from selected x-ray equipment and accessories. The swabbing procedure was carried out using sterile EveponTM swab sticks. The selected surfaces were first swabbed before being cleaned with chemical disinfectant of appropriate dilution. The surfaces were then cleaned with chemical disinfectant and swabbed again. A short time interval was allowed before the second swabbing for the disinfectant solution to dry. The swab samples were then taken to the microbiology laboratory for culturing and identification using standard laboratory procedure. Cystine lactose electrolyte deficient (CLED) and blood agar media were used to prepare the culture samples. The prepared samples were put in petri dishes and incubated for 24 hours at a temperature of 37°C. At the end of the incubation period, the samples were viewed under microscope to identify the bacteria. Bacteria were isolated in 142 swabs representing 47.2% of all the swab samples. Staphylococcus aureus, klebsiella spp, coliform and coagulase-negative staphylococcus epidermidis were the bacteria isolated from the swab samples. Klebsiella spp were isolated most often (49 times; 34.5%) and and coagulase-negative staphylococcus epidermidis were isolated the least number of times (18 times; 12.7%). The x-ray cassettes recorded the highest number of times bacteria were isolated (54 times; 38%) with coliform being isolated most often (45 times; 31.7%). Sodium hypochlorite was the most effective chemical disinfectant. No bacterial isolates were seen in the swab samples collected after its use.