title: Application of rapid read-out cleaning indicators for improved process control in hospital sterile services departments.
abstract: BACKGROUND
  Heightened awareness of the importance of cleaning has led to an emphasis on automated systems for the decontamination of re-usable medical devices. The authors have previously described an enzymatic indicator system, based on thermostable adenylate kinases (tAK), for quantitative monitoring of automated cleaning processes within hospital sterile services departments (SSDs).
  
  
  OBJECTIVE
  To evaluate tAK indicators for routine process monitoring across a range of SSDs with different cleaning chemistries and different automated washer disinfectors (AWDs).
  
  
  METHODS
  tAK indicator devices and alternative industry test indicators were included in five independent cleaning cycles in each of eight different AWDs. Residual tAK post wash was determined by a coupled luciferase assay using a modified hygiene monitoring system.
  
  
  RESULTS
  In all cases, with the exception of a single test, the alternative indicators showed that cleaning had been adequate. They were not able to discriminate between the performance of different processes. In contrast, the tAK indicators were able to resolve differences in the performance of processes across the different SSDs. Where the tAK indicators identified cleaning to the limits of detection of the assay, this demonstrated a log10 enzyme removal factor of >5.69.
  
  
  CONCLUSIONS
  The results suggest that tAK indicators are suitable for providing improved process control for automated cleaning processes, being able to distinguish between wash performance in different hospital settings and between individual process runs. This technology is believed to be a useful addition to routine AWD performance qualification when used as a daily or weekly test.
authors.affiliation: Microbiology Services Division, Health Protection Agency-Porton Down, Salisbury, UK. philip.nugent@hpa.org.uk
authors.forename: P G
authors.initials: PG
authors.lastname: Nugent
authors.forename: T
authors.initials: T
authors.lastname: Modi
authors.forename: N
authors.initials: N
authors.lastname: McLeod
authors.forename: L J
authors.initials: LJ
authors.lastname: Bock
authors.forename: C
authors.initials: C
authors.lastname: Smith
authors.forename: T M
authors.initials: TM
authors.lastname: Poolman
authors.forename: R
authors.initials: R
authors.lastname: Warburton
authors.forename: P
authors.initials: P
authors.lastname: Meighan
authors.forename: P
authors.initials: P
authors.lastname: Wells
authors.forename: J M
authors.initials: JM
authors.lastname: Sutton
mesh_terms: D000263:Adenylate Kinase / Q000032:analysis; D003666:Decontamination / Q000295:instrumentation* / Q000379:methods; D004202:Disinfectants / Q000032:analysis*; D004203:Disinfection / Q000295:instrumentation* / Q000379:methods; D004866:Equipment Contamination / Q000517:prevention & control; D005069:Evaluation Studies as Topic; D006761:Hospitals / Q000592:standards*; D009426:Netherlands; D006113:United Kingdom
chemical_list: D004202:Disinfectants; D000263:Adenylate Kinase