Elimination of high titre HIV from fibreoptic endoscopes

Concern about contamination of fibreoptic endoscopes with human immunodeficiency virus (HIV) has generated a variety of disruptive and possibly unnecessary infection control practices in endoscopy units. Current recommendations on the cleaning and disinfection of endoscopes have been formulated without applied experimental evidence of the effective removal of HIV from endoscopes. To study the kinetics of elimination of HIV from endoscope surfaces, we artificially contaminated the suction-biopsy channels of five Olympus GIF XQ20 endoscopes with high titre HIV in serum. The air and water channels of two instruments were similarly contaminated. Contamination was measured by irrigating channels with viral culture medium and collecting 3 ml at the distal end for antigen immunoassay. Endoscopes were then cleaned manualiy in neutral detergent according to the manufacturer's recommendations and disinfected in 2% alkaline glutaraldehyde (Cidex, Surgikos) for two, four, and ten minutes. Contamination with HIV antigens was measured before and after cleaning and after each period of disinfection. Initial contamination comprised 4*8X 104 to 3*5 X106 pg HIV antigenlml. Cleaning in detergent achieved a reduction to 165 pg/ml (99.93%) on one endoscope and to undetectable levels (100%) on four. After two minutes in alkaline glutaraldehyde ali samples were negative and remained negative after the longer disinfection times. Air and water channels, where contaminated, were tested after 10 minutes' disinfection and were negative. These findings underline the importance of cleaning in removing HIV from endoscopes and indicate that the use of dedicated equipment and long disinfection times