Microbiologic evaluation of needleless and needle-access devices

This study was carried out to determine whether needleless intravenous access devices are more likely to allow microorganisms to enter the fluid pathway than intravenous needle-access devices.

A laboratory study was conducted with two needleless and one intravenous needle-access devices and Enterococcus faecium as a bacterial challenge. Inocula of E. faecium were prepared on the basis of the numerical estimates of 1000 to 10,000 colony-forming units (CFU)/cm2 of bacterial flora on dry regions of skin (arms, legs, and hands). The septum of each access device was inoculated with 10 to 20 microliters of a 10(4) to 10(5) CFU/ml challenge suspension, which was allowed to dry on the surface of the septum. In the first part of the experiment, the needleless or needle-access cannula of each device was used to puncture the corresponding septum without previously disinfecting the top of the septum. In the second part, the contaminated septum was punctured after disinfecting the septum with a 70% isopropyl alcohol wipe. After each puncture, trypticase soy broth was flushed through the fluid pathway of the intravenous access device, collected, and cultured by the membrane filtration technique. The septum of each injection-site cap and the needleless or needle-access cannula were sampled with sterile premoistened swabs. Swabs were cultured on blood agar plates.

The rate of fluid pathway contamination was 100% (40/40) for one of the needleless intravenous access devices and 80% (20/25) for the other when septa were contaminated with E. faecium and not disinfected before puncture. The rate for the intravenous needle-access device was 72% (18/25). When the septa of the three different devices tested were disinfected with 70% isopropyl alcohol, E. faecium was isolated on only one septum from all devices tested in part two (1/74, 1.3%).

These laboratory studies demonstrate that there is no statistically significant difference in the rate of fluid pathway contamination between needleless and intravenous needle-access devices. However, if the septa of either needleless or needle systems are not disinfected before puncture, a high rate of fluid pathway contamination may occur.