Central Service 01/2018

Content Issue 01/2018 Central Service


  • Microbiological testing of the efficacy of cleaning and disinfection of the load (mechanical processing of uncritical medical devices)
  • IDSc Conference, 27 – 29 November 2017 in Blackpool
  • Letters: Comparison of protein detection test systems/ Validation of automated cleaning
  • Recommendations by the “Quality Task Group”: Risk assessment and release of new medical devices before investment and new procurement

Original Article:
Rapid enzymatic test system for the overall process efficacy of automated washer-disinfector processes for thermolabile endoscopes

Markus Wehrl*, Amelie Achten
Zentr Steril 2018; 26(1): 29–37.

Key Words: thermolabile flexible endoscopes, washer-disinfectors, overall process efficacy, routine control, validation, rapid enzymatic test system

Background: Process challenge devices (PCDs) according to Annex 9 of the Guideline are used for the process control of the overall reprocessing efficacy for thermolabile endoscopes. The analysis of these PCDs is sophisticated and requires a microbiological laboratory. These PCDs are therefore not appropriate for routine controls in central sterile departments.

Material and methods: Within a research project, a PCD system was developed that is simple and fast to use for the routine control of the overall process efficacy of processes that rely on glutaraldehyde as disinfectant. The system is based on special enzymes immobilized on a fibrin matrix in tubeshaped devices. The enzymes selected act as surrogates for the conventional test organisms (Enterococcus faecium), as the enzymes are equivalently denatured by process-typical temperatures and concentrations of the disinfectant.

Results: Comparative investigations in the laboratory as well as in hospitals demonstrated the good match of results between the new enzymatic test system and PCDs according to Annex 9.


From the Field:
Investigation of sterilization processes in healthcare institutions in Ulaanbaatar, Mongolia

T. Suvd-Erdene, T. Gantumur, W. Popp, N. Parohl*, C. Battogtokh
Zentr Steril 2018; 26(1): 43–47.

Key Words: Mongolia, CSSD, Sterilisers

The high prevalence of hepatitis B and C in the Mongolian population is imputed not least to inadequate reprocessing of the medical devices used. For the purpose of the current study conducted in 77 healthcare institutions in Mongolia, 105 autoclaves, three ethylene oxide (EO) sterilizers, one formaldehyde (FO) and one plasma (H2O2) sterilizer were investigated with biological indicators. 8% of the autoclaves and two of the three EO sterilizers showed unsatisfactory performance. The H2O2 and FO sterilizers tested inactivated the biological indicators.

Of the autoclaves, the older Russian models produced better results than the modern sterilizers from China and Korea. That may be due to the long experience with the old Russian appliances, which have no pre-vacuum, unlike with the more complex modern sterilizers. Thermologgers were used for the first time (in Mongolia) for measurement of physical parameters such as pressure, holding time and temperature. The findings indicate that inadequate reprocessing of medical devices may impact the high colonization rates with hepatitis viruses in Mongolia.