Estimation of average bioburden values on flexible gastrointestinal endoscopes after clinical use and cleaning: Assessment of the efficiency of cleaning processes

Abstract

Background: Endoscopy is a vital part of medical diagnostic processes. There are different kinds of flexible endoscopes used in medicine. They differ between manufacturers and even between models from the same manufacturer. However, all flexible endoscopes have the same basic components. Infections related to flexible endoscopic procedures are caused by either endogenous flora or exogenous microbes. The first major challenge of reprocessing is infection control, most episodes of infection can be traced to procedural errors in cleaning and disinfecting, the second major challenge is to protect personnel and patients from the exposure to liquid biocides used for disinfection. Because the endoscopic accessories have complex nature, attention and adherence to a validated protocol is critical for reprocessing endoscopic accessories. Bioburden is defined as the number of bacteria living on a surface that has not been sterilized. The term is most often used in the context of bioburden testing, also known as microbial limit testing, which is performed on pharmaceutical products and medical products for quality control purposes. Flexible endoscopes, by virtue of the types of body cavities they enter, acquire high levels of microbial contamination (bioburden) during each use.
Aim of the work: To detect the average bioburden values on different parts of flexible gastrointestinal endoscopes after clinical use and cleaning in order to assess the efficiency of different cleaning processes used in the endoscopy unit.
Methods: The current study included a total of 120 endoscopes randomly selected from Medical Research Institute (MRI) hospital 60 (50%) of which were from Surgical Department endoscopy unit, and 60 (50%) of which were from Internal Medicine Department endoscopy unit. The endoscopes were divided as (40) endoscopes after use (40) endoscopes after manual cleaning, and (40) endoscopes after high level disinfection. All samples were cultured for aerobic and anaerobic bacteria, and for Candida species, the number of colonies were determined as colony forming units (cfu)/ml.
Results: Microorganisms isolated immediately after use were Staphylococcus, Streptococcus, Klebsiella, Escherichia coli, and Bacteroides, whereas after manual cleaning the isolated strains were Staphylococcus, Streptococcus, Pseudomonas, Klebsiella, Bacteroides, and E. coli. The average Bioburden on endoscopy before cleaning ranged from 6 104 to 3.7 108 cfu per device (mean cfu per device 1.4 107), whereas after manual cleaning ranged from 2.1 102 to 3.5 103 cfu per device (mean cfu per device 4.9 102) and no colonies were found after sterilization. Manual cleaning resulted in a mean of 4.46 log10 reduction in viable colony count and high level disinfection (HLD) resulted in a reduction of CFU to zero.
Conclusions: HLD is superior to manual cleaning in the process of endoscopic disinfection. Recommendations: Microbiological screening should be undertaken for all the Endoscopy Unit personnel responsible for cleaning or if there is a clinical suspicion of cross-infection related to endoscopy. All health-care personnel in an endoscopy unit in standard infection control should be trained to reprocess endoscopes. Safe working practices in the decontamination area of each unit should be written down and understood by all staff.