Risk of microbial contamination of iodinated contrast media on multiple use of large-volume bottles

Large-volume bottles of iodinated contrast material (CM) offer advantages over single-dose vials in respect of handling, radiation protection of personnel, cost and waste. Because non-ionic CM are considered to be susceptible to microbial contamination, the probability of such contamination was investigated under practical conditions with reference to the duration of use. Under conditions identical to those in practice, contamination was found in only about 1% of bottles examined after a single piercing. Under worst-case conditions, a maximum of 9 microorganisms/bottle was found. No pathogen multiplication was observed within 24 h in microbial challenge tests; rather, the nosocomial pathogens examined died quickly in iopromide, the only exception being Pseudomonas aeruginosa. There was not a single case of bacterial multiplication on clinical use of 500-ml infusion bottles in patients undergoing routine computed tomography, using either injection by hand or an automatic infusion device. In conclusion, the microbial count rate did not differ from that of small-volume parenterals used up immediately after piercing. To ensure an adequate safety margin for the avoidance of septicemia or pyrogenic reactions, the CM should be used within 1 examination day.