DECONTAMINATION
respiratory droplets, the virus is also present in infected stools and may be detectable for several weeks after clinical recovery.2 SARS-CoV-2 viral shedding in stools has been reported both in symptomatic and asymptomatic patients. In infected patients the SARS-CoV-2 virus has been detected in stool samples in up to 50% of cases.2
This
is similar to other coronaviruses such as SARS-CoV-1 and MERS-CoV. In SARS-CoV-1 infection, persistent stool viral shedding was observed to occur beyond the second week of infection.2 Similarly, SARS-CoV-2 has been found in stool samples at day 17 in asymptomatic individuals with prior exposure to the virus.2 Whether stool shedding of viral particles can transmit infection is, at present, unclear.7
However, all endoscopic and decontamination procedures should be performed with stringent safety precautions and awareness that they may pose a risk of SARS-CoV-2 transmission.7 As SARS-CoV-2 is also known to be transmitted via fomites, there is a risk of viral transmission to patients via contaminated endoscopes, as has happened previously with hepatitis B and C and various multidrug resistant organisms.3 The shedding of SARS-CoV-2 viruses in faeces means COVID-19 could be transmitted by contaminated endoscopes, which could theoretically occur due to contact with mucous membranes and body fluids. As GI endoscopies involve close contact with colonic contents this can increase the risk of contamination and contribute to virus transmission.2 Even before the current pandemic, outbreaks of infections with highly resistant micro-organisms, highlighted the problems of contaminated endoscopes and lapses in the correct reprocessing of flexible endoscopes have been recorded in the pre-cleaning as well as in the automated reprocessing stages.2
Effective reprocessing of flexible endoscopes involves pre-cleaning, leak testing, cleaning and high level disinfection followed by rinsing and drying before storage.1
Cleaning must precede high level disinfection to remove organic debris (e.g. blood, faeces, respiratory secretions) from the external surface, lumens and channels of flexible endoscopes. Inadequate cleaning of flexible endoscopes has been frequently associated with microbial transmission during endoscopic procedures.6 The manual cleaning procedure for flexible endoscopes includes brushing of the external surface and removable parts (e.g. suction valves) and immersion in a detergent solution followed by irrigation of internal channels with a detergent. The endoscope and accessories should be inspected for damage and a leak test should be performed before disinfection.6
Automated Endoscope Reprocessors (AER) are strongly recommended for the reprocessing of flexible endoscopes to minimise contamination and contact with
chemicals and soiled instruments. However, a defective AER can result in inadequate reprocessing. The presence of biofilms in defective AERs has been detected during these failings.6
According to the Joint Advisory Group on Endoscopy (JAG), infection prevention measures for reprocessing endoscopes should be put in place by Trusts, in line with national guidance. This should be supported by standard operating procedures (SOPs) and updated as further guidance is published.8
Decontamination best practice should be followed especially in red sites. This includes the reprocessing of endoscopic equipment immediately after use with strict adherence to manual cleaning processes. Red refers to areas or patient pathways with proven or suspected COVID-19.8 As a part of preparing and implementing robust Standard Operating Procedures, the choice of cleaners and disinfectants used in the reprocessing process is a key consideration. The decontamination process involves mechanical and detergent cleaning, followed by high-level disinfection, rinsing and drying.9
The cleaning stage is essential to the efficacy of the subsequent disinfection stage. Cleaning refers to the removal of soil and other organic contaminations from a device using the physical action of scrubbing and the chemical action of a detergent. Cleaning not only removes gross contamination, but, in addition, removes large numbers of microorganisms, which reduces the levels of organic bioburden on these surfaces. This process is designed to remove organisms rather than kill them9
and the choice of a
suitable detergent is a key factor. It must always precede disinfection and helps to ensure the efficacy of the subsequent disinfection step,10,11
especially on surfaces
like endoscopes with visible contamination. The BSG stipulates that thorough manual
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