الفهرس 
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Abstract
Endoscopy means examination of the inside of the body by using a lighted, flexible device called an endoscope.
Gastrointestinal endoscopes are commonly and increasingly used for minimally invasive, therapeutic and diagnostic interventions. They are considered as semi-critical devices and should receive high level disinfection because they contact with mucosal membranes during these procedures, which can cause microbial contamination within the channels and on the surface of the endoscope.
There are two methods of endoscopic reprocessing: automated and manual endoscope reprocessing. The steps of reprocessing consist of precleaning, cleaning, disinfection, washing, drying, and finally storage. Breakdown in any step of reprocessing can lead to the risk of infection transmission.
Infections related to theendoscopy are either endogenous infections cause by the patient’s own microbial flora or exogenous infections caused by inadequately reprocessing.
Biofilm is a matrix of several types of bacteria and extracellular material that can adhere to the interior surfaces of endoscopes tightly. Biofilm formation on the inner surface of endoscope channels, specifically when thesechannels become scratched or destroyed, can result in failure of the decontamination procedure, and results in outbreaks of endoscopy linked infections.
The aim of the present study was the assessment of decontamination procedures of the clinical endoscopy channels in Medical Research Institute of Alexandria University.
In the present study two hundred samples (100 before brush and 100 after brush) were collected from gastroscope, colonyscope and ERCP of Endoscopy Unit of Internal Medicine Department, Medical Research Institute hospital, Alexandria University.
The identification of samples was carried out by culture on blood, MacConkeyand sabouraud dextrose agar.Microscopic examination and biochemical tests were used for identification of microorganisms. Then detecting the ability of microorganisms to form biofilm and measuring the sensitivity of microorganisms to the disinfectant used in endoscopy unit were done.
The present study showed that the rate of microbial growth in all the 200 samples was 31%;Pseudomonas species was 20%, Klebsiella species was 8.5%, E.coli was 1.5% and fungal species was 1%.
Regarding the type of endoscope, the present study demonstrated that from the 128 gastroscope samples; 28 samples gave positive growth which represented 21.8% of total gastroscope samples collected.from 38 colonoscopy samples; 17 samples gave positive growth which represents 44.7 % of total colonyscopesamples collected, and from 34samples; 17 samples yielded positive growth which represents 50% of total ERCP samples collected.
The bacterial ability to form biofilm; 5 isolates (26.3%) ofpseudomonas species before brushing were able to form biofilm from 19 pseudomonas spp. isolates, while after brushing 13 (61.9%) isolates were able to form biofilm from 21 pseudomonas spp. isolates.One isolate (14.2%) of klebsiella species before brush was able to form biofilm from 7 Klebsiella spp. isolates while after brushing 4 (40%) isolates were able to form biofilm from 10 Klebsiella spp.isolates.E.coliwas negative in biofilm formation both before and after brushing.
The bactericidal test of sensitivity of bacterial samples to OPA disinfectant that was used in the endoscopy unit was performed at different contact times (10, 12, 15 minutes). At 10 minutes all bacterial species (pseudomonas spp., Klebsiella spp., E.coli) were stable to the OPA inhibitory effect, while after 12 minutes only pseudomonas spp. was stable with high colony counts(>100), and after 15 minutespseudomonas spp. was also present but with lower colony counts (<30).
In the present study samples were taken before and after doing the recommended changes in the storage condition (improvements in storage conditions). Pre action the rate of microbial growth was (40%) which was much higher than the rate of post action (9%).
from this study we can conclude the followings:
1. Failure in any step of endoscopy reprocessing can result in transmission of infections.
2. Most bacterial isolates in the channels of endoscopies are able to form biofilm.
3. Biofilm increases the resistance of bacteria to the disinfectants used in reprocessing.
4. Inappropriate storage conditions of endoscopes can lead to contamination in the endoscope channels.
ERCP