Microbiologic contamination of automatic injectors at MDCT: experimental and clinical investigations.

OBJECTIVE: It is mandatory to teach antiseptic skills to staff who use contrast agent injectors. The purpose of this study was to evaluate in an experimental setting and in clinical routine the risk of microbiologic contamination of the syringes of injectors used to administer contrast agent and saline solution for MDCT.
MATERIALS AND METHODS: Microbiologic contamination of CT injector syringes over multiple uses for several injections was investigated in an experimental setup simulating the clinical setting. Each refill and injection operation was performed by the same technician, who processed a contrast agent for administration in a neighboring room as in clinical CT routine. Multiple administrations of nutritive medium and a chaser bolus were performed with the injection syringes. Simultaneously with each syringe replacement and filling operation, the filling and injection operation was simulated with a separate injection system under normal clinical conditions. Hygienic conditions in the CT department also were evaluated. For microbiologic analysis of devices and of palms of staff, imprints were obtained during clinical routine at the beginning of the study and at follow-up. Throughout the study, the staff participated in continuing education on hygienic behavior, such as hand disinfection and wearing of sterile gloves. In addition, clinical injector syringes were checked for microbiologic contamination.
RESULTS: In the experimental setup, the first four samples of each simulation experiment were sterile, and the subsequent probes were found to be contaminated with typical dermal bacteria, such as staphylococci. In the CT department, contamination with skin and oral flora was found on surfaces of devices and on palms. No imprint of surfaces or palms was contaminated with nosocomial or fecal pathogens.
CONCLUSION: Because even optimization of environments does not prevent contamination of syringes, multiple uses of syringes for more than one patient should be prohibited owing to the risk of septic complications.