Bacterial contamination of multiple-dose vials: a prevalence study

Background Two patients died of a meningitis caused by Pseudomonas aeruginosa in a hospital in Germany in July 2001, their infections having been caused by a contaminated contrast media (iomeprol [Imeron]) used as a multiple-dose vial (MDV) over 8 days. Therefore, a prevalence study was performed to investigate the use and contamination of multiple-use vials in a tertiary hospital. Methods In a 1300-bed hospital on a specific day in November 2001, all used MDVs were collected by the infection control nurses. Information was recorded about the medication, labeling of vials, storing temperature, wards, and dates of opening. Each vial was also tested for sterility. Results Opened vials were to be found in all wards. Of the 227 vials available, 1 vial and 1 spike were contaminated with Staphylococcus epidermidis (contamination rate 0.9%; 95% CI, 0.3-2.1). The opening dates were marked on only 114 (50%) MDVs, 15 (13%) of which had already expired. Only 44 (19%) MDVs had been stored in the refrigerator, whereas 109 MDVs contained medications without any preserving agent. Conclusion Results revealed somewhat risky handling of MDVs. In light of a possible high risk in this hospital of about 1 contaminated MDV per day, and in view of many reported outbreaks induced by contaminated MDVs, the following infection control measures were encouraged: alcohol hand hygiene, the disinfection of gums, observance of the manufacturerʹs recommendations, appropriate storing temperatures, marking the opening time, and avoiding the multiple use of medications not containing preserving agents.