Endoscope sampling and culturing methods

Abstract

Contamination rates reported in the literature for patient-ready flexible endoscopes vary from 0.4% to 49%. Unfortunately, the comparison and interpretation of these results is almost impossible since several factors including sampling and culturing methods, target levels for contamination or definition of indicator microorganisms vary widely from one study to the other. The objective of this study was to compare the efficacy of six duodenoscope sampling and culturing methods by means of extraction efficacy comparison, while at the same time identifying key parameters that provide optimal microbial recovery.The duodenoscope sample extraction efficacy of each method was assessed using the repetitive recovery method described in ISO 11737-1: 2018. The results obtained indicated that the mean overall bioburden extraction efficacy varied from 1% for the Australian method to 39% for the French one. The lowest endoscope sample extraction efficacy was associated with the absence of any neutralizer, friction, or tensioactive agent and when only a small portion of the sampling solution collected was inoculated onto culture media.The efficacy of the sampling and culturing methods also varied according to the nature of microorganisms present in the endoscope, and the time between sampling and culturing.This study supports the need for a harmonized and standardized sampling and culturing method for flexible endoscopes.