M J Alfa1, N Olson2, B-L Murray2. 1. Department of Medical Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada; Microbiology and Infectious Disease Laboratory, St. Boniface Research Centre, Winnipeg, Manitoba, Canada. Electronic address: malfa@sbrc.ca. 2. Microbiology and Infectious Disease Laboratory, St. Boniface Research Centre, Winnipeg, Manitoba, Canada.
Abstract
BACKGROUND: Ensuring cleaning compliance of housekeeping staff is critical to ensure adequate application of surface disinfectants. Adenosine triphosphate (ATP) testing has been recommended as a way to monitor cleaning compliance; however, little is known about the stability of ATP on environmental surfaces. AIM: To assess the stability of ATP from various sources to determine if it is stable for sufficient time to be an effective means of assessing environmental cleaning and disinfection in health care. METHODS: Purified ATP, ATP derived from ATS-T (blood-based test soil) and ATP derived from 10(7) colony-forming units/site of micro-organisms (Pseudomonas aeruginosa, Enterococcus faecalis, Candida albicans) were evaluated in liquid suspension and dried on to surfaces to assess stability over 29 days. Cleaners and disinfectants were sprayed on to surface-dried material with no wiping to determine their effect on microbial viability and ATP stability. FINDINGS: Surface-dried P. aeruginosa, E. faecalis and C. albicans retained 65-96% of their original ATP level on Day 29, despite reduced or no viability. Surface-dried ATS-T had 100% and 3% of its original ATP on Days 4 and 29, respectively. Deterioration of the ATP signal was most pronounced for suspensions. Purified ATP was stable over 29 days in suspension or dried on to a surface. CONCLUSIONS: ATP residuals from organic material and micro-organisms (dead or alive) are stable when dried on to surfaces. In the absence of cleaning and disinfection, the relative light unit signal will not deteriorate rapidly, making ATP a good marker to monitor cleaning.
BACKGROUND: Ensuring cleaning compliance of housekeeping staff is critical to ensure adequate application of surface disinfectants. Adenosine triphosphate (ATP) testing has been recommended as a way to monitor cleaning compliance; however, little is known about the stability of ATP on environmental surfaces. AIM: To assess the stability of ATP from various sources to determine if it is stable for sufficient time to be an effective means of assessing environmental cleaning and disinfection in health care. METHODS: Purified ATP, ATP derived from ATS-T (blood-based test soil) and ATP derived from 10(7) colony-forming units/site of micro-organisms (Pseudomonas aeruginosa, Enterococcus faecalis, Candida albicans) were evaluated in liquid suspension and dried on to surfaces to assess stability over 29 days. Cleaners and disinfectants were sprayed on to surface-dried material with no wiping to determine their effect on microbial viability and ATP stability. FINDINGS: Surface-dried P. aeruginosa, E. faecalis and C. albicans retained 65-96% of their original ATP level on Day 29, despite reduced or no viability. Surface-dried ATS-T had 100% and 3% of its original ATP on Days 4 and 29, respectively. Deterioration of the ATP signal was most pronounced for suspensions. Purified ATP was stable over 29 days in suspension or dried on to a surface. CONCLUSIONS:ATP residuals from organic material and micro-organisms (dead or alive) are stable when dried on to surfaces. In the absence of cleaning and disinfection, the relative light unit signal will not deteriorate rapidly, making ATP a good marker to monitor cleaning.