Ultraviolet-C irradiation for prevention of central venous catheter-related infections: an in vitro study

Abstract

Central venous catheters (CVC) are widely used in the United States and are associated with 250,000 to 500,000 CVC-related infections in hospitals annually. We used a catheter made from ultraviolet-C (UVC) transmissive material to test whether delivery of UVC from the lumen would allow inactivation of microorganisms on the outer surface of CVC. When the catheter was exposed to UVC irradiation from a cold cathode fluorescent lamp inside the catheter lumen at a radiant exposure of 3.6 mJ cm(-2) , more than 6-log(10) of drug-resistant Gram-positive bacteria adhered to the outer surface of the catheter were inactivated. Three to 7-log(10) of drug-resistant Gram-negative bacteria and 2.80-log(10) of fungi were inactivated at a radiant exposure of 11 mJ cm(-2).UVC irradiation also offered a highly selective inactivation of bacteria over keratinocytes under exactly comparable conditions. After 11 mJ cm(-2) UVC light had been delivered, over 6-log(10) of bacteria were inactivated while the viability loss of the keratinocytes was only about 57%.

© 2010 The Authors. Photochemistry and Photobiology © 2010 The American Society of Photobiology.

Figures

Figure 1

A) Routes to develop a CVC-related infection. B) Schematic of prototype device showing a UVC cold cathode fluorescent lamp (UVC-CCFL) disposed in the lumen of a catheter. C) Schematic of UVC inactivation of microorganisms on the outer surface of catheter. D) Schematic of the geometrical selectivity of UVC inactivation of microorganisms on catheter surface over cells on vessel wall.

Figure 2

A) Comparison of the absorbance in the UV range of two commercial catheters (NuSil 1 and NuSil extrude) and the prototype device catheter; B) Spectral power distribution of the prototype device UVC tube measured with and without catheter.

Figure 3

A) Quantification of colony forming units: 10-folder serial dilutions of microorganism suspensions; and streak of a set of serial dilutions of microorganism suspension on agar plate. B) Time-dependent survival fraction in response to UVC irradiation of Gram-positive bacteria on the outer surface of catheter. C) Time-dependent survival fraction in response to UVC irradiation of Gram-negative bacteria on the outer surface of catheter. D) Time-dependent survival fraction in response to UVC irradiation of fungi on the outer surface of catheter. Bars: standard deviation.

Figure 4

A) A representative set of images showing the colonies (crystal violet stained) of keratinocyte cultures exposed to UVC irradiation at various radiant exposures. B) Comparison of averaged fluence-dependent survival fractions in response to UVC irradiation of bacteria with that of keratinocytes using identical irradiation conditions and colony-forming assays. Bars: standard deviation.