A search strategy for detecting duodenoscope-associated infections: a retrospective observational study

Abstract

Duodenoscope-associated infections (DAI) are exogenous infections resulting from the use of contaminated duodenoscopes. While numerous outbreaks of DAI involved multidrug-resistant microorganisms (MDRO), outbreaks involving non-MDRO are also likely to occur. Detection challenges arise as these infections often resolve before culture or because causative strains are not retained for comparison with duodenoscope strains. This retrospective observational study aims to identify and analyse DAIs spanning a seven-year period. Duodenoscope cultures positive for gastrointestinal flora between March 2015 and September 2022, were paired with duodenoscope usage data to identify patients exposed to contaminated duodenoscopes. Our analysis encompassed patients treated after a positive duodenoscope culture and those treated within the interval from a negative to a positive culture. Patient identification numbers were cross-referenced with a clinical culture database to identify patients developing infections with matching microorganisms within one year of their procedure. A "pair" was established upon a species-level match between duodenoscope and patient cultures. Pairs were further analysed via antibiogram comparison, and whole-genome sequencing (WGS) to determine genetic relatedness. A total of 68 pairs were identified, and among them, 21 exhibited matching antibiograms. These pairs underwent WGS, which uncovered two genetically closely related pairs categorized as DAIs. Infection onset occurred up to two months post-procedure. Both causative agents were non-MDRO. This study provides crucial insights into DAIs caused by non-MDRO and highlights the challenge of DAI recognition in daily practice. Importantly, the delayed manifestation of the described DAIs suggests a current underestimation of DAI risk.