Contamination of portable radiograph equipment with resistant bacteria in the ICU

Approximately 15% of nosocomial infections in the ICU result from spread of bacteria on caregivers' hands. The routine chest radiograph provides an unexamined opportunity for bacterial spread: close contact with each patient and sequential examination of ICU patients. This study examined infection control procedures performed during routine chest radiographs, assessed whether resistant bacteria were transferred to the radiograph machine, and determined whether improved infection control practices by radiograph technicians could reduce bacterial transfer.

Radiograph technicians were observed performing chest radiographs on all ICU patients. Culture specimens were taken from the radiograph machine. An educational intervention directed at technicians was instituted, and its effect on infection control and machine contamination was measured.

Surveillance of 173, 113, and 120 chest radiographs during observation, intervention, and follow-up periods was performed. Adequate infection control was practiced during the performance of 2 of 173 observation period radiographs (1%), 48 of 113 intervention period radiographs (42%; p < 0.001), and 12 of 120 follow-up period radiographs (10%; (p < 0.001) [follow-up vs intervention and observation periods]. Radiograph machine surface culture samples yielded resistant Gram-negative bacteria on 12 of 30 occasions (39%), 0 of 29 occasions, and 7 of 14 occasions (50%), respectively, for the observation, intervention, and follow-up periods (p < 0.001).

Multiresistant bacteria are frequently transferred from patients to the radiograph machine in the presence of poor infection control practices, and may be a source of cross-infection/colonization. Improved infection control practices decrease the occurrence of resistant organisms on the radiograph equipment. Radiograph technicians should be included in efforts to improve infection control measures.