Bacterial contamination upon the opening of injection needles

Two opening methods are used for injection needle products: the "peel-apart method" where the adhesive surface of the packaging mount is peeled off, and the "push-off top method," where the needle hub is pressed against the mount to break it. However, the risks of bacterial contamination as a result of opening method remain unknown. The aim of our study was to evaluate the bacterial contamination of needle hubs upon the opening of injection needles by the peel-apart or push-off top method under various conditions.

Bacterial contamination upon the opening of injection needles was examined in two materials, paper and plastic. Various concentrations of Staphylococcus aureus were applied to the mount and were maintained under wet or dry conditions. Injection needles were opened using the peel-apart or push-off top method. Needle hub contamination was examined using agar medium colony counting. Clinically assumed conditions (the hands and saliva of anesthesiologists) were also evaluated. Data were statistically examined using the Cochran-Mantel-Haenszel, Jonckheere, and Fisher's exact tests.

The lateral surfaces of needle hubs were contaminated using the push-off top method, but not by the peel-apart method, in a manner that was dependent on S. aureus concentrations. No significant differences were observed between mount materials. Needle hub contamination was significantly more severe for the wet than for the dry opening portion. The clinically assumed condition study revealed that the lateral and bottom surfaces of the needle hub were contaminated significantly more in the saliva contamination group than in the dry and wet hand groups.

The bacterial contamination of needle hubs may occur upon the opening of injection needles when the push-off top method is used and may be affected by hands contaminated with saliva under clinical conditions.