[Effectiveness of instrument disinfectants under increased protein exposure and for standing times up to two weeks].
To examine the possibility of prolongation of the standing times of instrument disinfectants, in vitro tests under high albumin exposure and tests in clinical practice were done. Concerning in vitro tests: The bactericidal effectiveness of 7 commercial preparations for instrument disinfection with different basic substances was determined in quantitative suspension tests and of 8 preparations in practice-oriented tests according to the guidelines for testing and approval of instrument disinfectants by the DGHM (German Society for Hygiene and Microbiology). Tests were carried out under increased albumin exposure and at prolonged standing times up to 12 days. The instrument disinfectants showed microbicidal efficacy up to 12 days at working concentrations slightly increased in relation to the concentrations listed by the DGHM. Concerning tests in clinical practice: In 4 clinical wards (intensive care unit, cystoscopy unit, urological operation unit, gastroenterological endoscopy unit with ERPC) the preparations for instrument disinfection were tested up to 12 days in respect to the protein exposure and the disinfecting activity of the working solution. The working solution was not renewed during the 12 days. The inserted instruments were recorded. Concentration of the disinfectants and the protein concentration were daily determined. Disinfecting activity was examined by practice-oriented microbiological tests. The highest protein exposure was 0.098% after a standing time of 12 days. A loss in concentration of disinfectants could not be found. Nevertheless independent from the protein exposure there was a loss in disinfecting activity of the tap water diluted specimens from the clinical practice. Loss in activity could not be seen in the specimen from laboratory parallel tests, which were diluted by water of standard hardness. The loss in disinfecting activity of the tap water diluted preparation from the gastroenterological endoscopy unit versus a dilution by water of standard hardness could be confirmed in control experiments (practice-oriented tests with S. aureus over a period of 5 days).
Rehork
B
B
Institut für Hygiene, Freien Universität Berlin.
Azzaui
S
S
Naumann
C
C
Rüden
H
H
D000418:Albumins; D001419:Bacteria / Q000187:drug effects*; D004202:Disinfectants / Q000494:pharmacology / Q000592:standards*; D004203:Disinfection; D004865:Equipment and Supplies, Hospital; D006801:Humans; D013997:Time Factors
D000418:Albumins; D004202:Disinfectants