GI flexible endoscope disinfection: "in use" test comparative study.
OBJECTIVE
There is some confusion as to the effectiveness of the available disinfectants for achieving "high level" disinfection, and the microbiologic method to assess the efficacy of the selected disinfectant regime. The "in use" method is adequate for control and for establishing comparisons between different disinfectants.


METHODS
This study compares the efficacy of the different disinfectants and disinfection regimes available, including automatic systems to the 20-minute immersion in 20 degrees C 2%-alkaline-glutaraldehyde (AG). After cleaning and disinfection the effluent obtained from each channel was collected under sterile conditions. A total of 0.1 mL of the effluent was introduced in liquid thioglycolate, an additional 0.1 mL was seeded in solid blood agar and in MacConkey agar medium, and maintained for 48 hours at 37 degrees C. Thioglycolate media turbidity after a 48-hour culture indicates bacterial growth.


RESULTS
The disinfectants used were 2% AG, 0.125% and 0.27% glutaraldehyde, glutaraldehydephenol-phenate, peracetic acid, N-duopropenida, 13%-H2O2-27%-lactic acid and ortho-phtalaldehyde using manual and automated methods. Most of the disinfectants available obtain similar or better results compared with 20' 2% AG. The best results (bacterial reduction greater than 3 log10), were those obtained using 20-minute 1/4 or 1/2 glutaraldehydephenol-phenate, 10-minute peracetic acid, or hydrogen-peroxide compounds, 5-minute 0.125% and 0.27% AG at high temperature and 5-minute 0.5% ortho-phtalaldehyde.


CONCLUSIONS
A sensitive microbiologic method described may be useful in the control of disinfection and allowed: 1) knowledge of the limits of the efficacy of the disinfection methods usually used, 2) effective comparison of the different disinfectants and disinfection regimes and 3) awareness of the need for microbiologic regulations in assessing "high level" disinfection.
Bordas
Josep M
JM
GI Endoscopy, Motility and Functional Tests, Institut de Malalties Digestives, Institut Malalties Digestives, Hospital Clinic, Facultat de Medicina Universitat de Barcelona, Barcelona, Spain. jmbordas@clinic.ub.es
Marcos-Maeso
M Angeles
MA
Perez
M Jesus
MJ
Llach
Josep
J
Gines
Angels
A
Pique
Josep M
JM
D015169:Colony Count, Microbial; D004202:Disinfectants / Q000494:pharmacology*; D004203:Disinfection / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D020776:Endoscopes, Gastrointestinal / Q000382:microbiology*; D005976:Glutaral / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration
D004202:Disinfectants; D005976:Glutaral