Pre-Use Ureteroscope Contamination after High Level Disinfection: Reprocessing Effectiveness and the Relation with Cumulative Ureteroscope Use.

Purpose: We assessed the frequency of preoperative and persistent microbial contamination of flexible ureteroscopes after reprocessing and the relation of contamination to cumulative ureteroscope use.
Materials and Methods: We evaluated the effectiveness of high level disinfection with peracetic acid as well as data on ureteroscope use for 20 new flexible ureteroscopes from December 2015 to December 2017 at a single center. In the operating room pre-use and postuse microbial samples of the ureteroscope shaft and working channel were collected to evaluate microbial contamination after reprocessing. Positive cultures were defined as 30 cfu/ml or greater of skin flora, or 10 cfu/ml or greater of uropathogenic microorganisms. A generalized estimating equation model was used to analyze whether cumulative ureteroscope use was associated with positive pre-use cultures.
Results: Microbial samples were collected during 389 procedures. Pre-use ureteroscope cultures were positive in 47 of 389 procedures (12.1%), of which uropathogens were found in 9 of 389 (2.3%) and skin flora in 38 of 389 (9.8%). Urinary tract infection symptoms did not develop in any of the patients who underwent surgery with a uropathogen contaminated ureteroscope. In 1 case the pre-use culture contained the same bacteria type as the prior postuse culture. Cumulative ureteroscope use was not associated with a higher probability of positive cultures.
Conclusions: Microbial contamination of reprocessed ureteroscopes was found in an eighth of all procedures. Notably uropathogenic microorganisms were discovered in a small proportion of all procedures. Persistent ureteroscope contamination with uropathogens was only rarely encountered. Cumulative ureteroscope use was not associated with a higher probability of microbial contamination.