Surveillance of Endoscopes: Comparison of Different Sampling Techniques

Abstract

OBJECTIVETo compare different techniques of endoscope sampling to assess residual bacterial contamination.DESIGNDiagnostic study.SETTINGThe endoscopy unit of an 1,100-bed university hospital performing ~13,000 endoscopic procedures annually.METHODSIn total, 4 sampling techniques, combining flushing fluid with or without a commercial endoscope brush, were compared in an endoscope model. Based on these results, sterile physiological saline flushing with or without PULL THRU brush was selected for evaluation on 40 flexible endoscopes by adenosine triphosphate (ATP) measurement and bacterial culture. Acceptance criteria from the French National guideline (<25 colony-forming units [CFU] per endoscope and absence of indicator microorganisms) were used as part of the evaluation.RESULTSOn biofilm-coated PTFE tubes, physiological saline in combination with a PULL THRU brush generated higher mean ATP values (2,579 relative light units [RLU]) compared with saline alone (1,436 RLU; P=.047). In the endoscope samples, culture yield using saline plus the PULL THRU (mean, 43 CFU; range, 1–400 CFU) was significantly higher than that of saline alone (mean, 17 CFU; range, 0–500 CFU; P<.001). In samples obtained using the saline+PULL THRU brush method, ATP values of samples classified as unacceptable were significantly higher than those of samples classified as acceptable (P=.001).CONCLUSIONPhysiological saline flushing combined with PULL THRU brush to sample endoscopes generated higher ATP values and increased the yield of microbial surveillance culture. Consequently, the acceptance rate of endoscopes based on a defined CFU limit was significantly lower when the saline+PULL THRU method was used instead of saline alone.Infect Control Hosp Epidemiol 2017;38:1062–1069

Sterile Reverse Osmosis Water Combined with Friction Are Optimal for Channel and Lever Cavity Sample Collection of Flexible Duodenoscopes

“…The pull-through channel cleaning device was the most effective at removing fixed residuals as visualized using the borescope (regardless of extraction fluid). This supports the conclusion by Cattoir et al ( 11 ) regarding the efficacy of pull-through sample extraction and extends their findings as our PTFE data evaluated the glutaraldehyde-fixed BBF [not unfixed biofilm as used by Cattoir et al ( 11 )] as well as detection of low levels of bacteria (range 0.33–2.25 Log10 CFU/segment) using sample concentration for culture. Cattoir et al ( 11 ) did not provide CFU data for their biofilm or non-biofilm PTFE channel model (they reported % recovery), so no comparison can be made regarding the efficacy of their recommended sample extraction protocol when low levels of bacteria are present.…”

“…The key issues in sample collection methods used to assess contamination of flexible endoscopes includes protection of organism viability and CFU count during transport of the sample, extraction efficiency of both Gram-positive, Gram-negative, and fungal organisms from fixed residuals within the endoscope channel, ensuring stimulation of growth for VBNC bacteria that may be present in the sample, compatibility with the endoscope materials and concentration of the sample to improve the limit of detection on culture. Although there have been a number of studies published using many of the extraction fluids that we tested ( 3 , 4 , 9 – 11 , 18 ), our data are the first to show that the extraction fluids can detrimentally affect the viability of the bacteria held for 24 h at room temperature. There was a 1–2 Log 10 reduction in viable E. coli but not E. faecalis in RO and PBS with or without 0.02% Tween80 over a 24-h period.…”

“…One aspect of endoscope sample collection that is often overlooked when culturing endoscopes ( 3 , 4 , 7 , 11 , 17 , 19 , 23 ) is the need to use a “neutralizer” to ensure that trace residuals of antimicrobial agents (e.g., HLDs) are inactivated ( 9 , 13 , 15 , 24 ). In addition, the use of a neutralizing agent ensures that organisms with sub-lethal injury are protected and stimulated to grow on culture thereby reducing VBNC issues when culture is used to determine if endoscopes are contaminated ( 9 , 25 ).…”

“…The recent outbreaks due to contaminated flexible endoscopes ( 1 , 2 ) have raised questions regarding the frequency and optimal method to use for sampling endoscopes especially duodenoscopes ( 2 – 11 ). Endoscope culture results may be affected by various factors including viable but non-culturable (VBNC) organisms ( 5 , 12 , 13 ), use of neutralizer to ensure protection and growth of damaged organisms ( 5 , 10 , 12 , 14 , 15 ), type of fluid used to extract samples from channels ( 3 , 16 ), and type of friction [e.g., brush or swab for extraction from channels and lever cavity ( 4 , 5 , 11 , 16 )]. Indeed, Kim and Muthusamy ( 6 ) stated: “ … a negative culture does not ensure sterility or even exclude the possibility of a contaminated duodenoscope .” Biofilm developing and accumulating in patient-used endoscopes with repeated rounds of reprocessing ( 10 , 17 ) has been recognized as an issue associated with moisture in channels during storage ( 18 ).…”

Monthly endoscopy surveillance culture facilitates detection of breaches in the scope reprocessing procedure: 5 year-experience in an endoscopy center

“…However, this method shows a poor correlation with cultures of fully reprocessed devices [4] and requires extra work, particularly in a high-volume unit. The microbiological culture of endoscopes is critical to understanding the e cacy of reprocessing and transmission of microorganisms during outbreak investigations [8,17,18,[21][22][23]. However, the existing guidelines are inconsistent in terms of the recommended frequency and method of microbiological monitoring [7,9,24] (Table 6).…”