Types of disinfection processes examined in the microbiological S2 laboratory:

• Low- Level Disinfektion: Four test organisms to be tested
• S. aureus ATCC 6538
• P. aeruginosa ATCC 15442
• E. coli K12 NCTC 10538
• Kl. Pneumoniae ATCC 13883
• High- Level Disinfektion: One test organisms to be tested
• M. terrae ATCC 15755

The medical instruments / devices to be tested are inoculated with a defined amount of bacterial suspension. After visual drought, the instruments or devices are subjected to the disinfection process (wiping or immersion disinfection).

Subsequently, the contaminated site is examined for presence of viable microorganisms using a suitable recovery process. In parallel, a non-disinfected reference (positive control, inoculated but not disinfected) and a negative control (not inoculated but cleaned and disinfected) are included.

Acceptance Criteria:

The disinfection process (high or low level disinfection) is considered successful if a reduction of the number of viable microorganism by six log steps is detected for all microorganisms tested..

Standards and guidelines:

• E1837: Standard test method to determine efficacy of disinfection processes for reusable medical devices (2014)
• E1054: Standard Test Methods for Evaluation of Inactivators of Antimicrobial Agents1
• FDA Guidance: Reprocessing Medical Devices in Health Care Settings: Validation Methods and Labeling June 9, 2017
• FDA Guidance : Medical washers and medical washer- disinfectors February 7, 2002