How can endoscopic transmission of Helicobacter pylori bacteria be prevented?

Helicobacter pylori infection is recognized as one of the most prevalent infections worldwide and a major cause of morbidity and mortality. Transmission of the bacteria during gastrointestinal endoscopy is a concern for both healthcare professionals and patients.

About Helicobacter pylori infection

Helicobacter pylori is a gram-negative, spiral-shaped bacterium that mainly populates and multiplies in the gastric mucosa. The bacterium produces the enzyme urease which converts urea into carbon dioxide and ammonia. This allows it to survive in the acidic environment of the stomach (Guarner, 2004).

Helicobacter pylori infection is the most common infection of the stomach worldwide, as a result of which a proportion of the population develops symptoms of dyspepsia with the diagnosis of gastritis or peptic ulcer, and another proportion develops preneoplastic lesions or neoplasms (gastric adenocarcinoma of the intestinal type or mucosa-associated lymphoid tissue lymphoma) (FitzGerald & Smith, 2021). It also increases the risk of gastroduodenal ulceration and bleeding in patients taking nonsteroidal anti-inflammatory drugs (Katelaris, et al., 2021).

It is estimated that approximately 50% of the world’s population is infected. The prevalence of infection varies widely by geographic area, age, race, ethnicity, and socio-economic impact, and the rate appears to be higher in developing countries than in developed countries (Brown, 2000).

The mode of transmission of Helicobacter pylori is not fully known. It can be transmitted from person to person (oral-oral, gastro-oral, fecal-oral routes, through breastfeeding), but also through consumption of contaminated food (especially raw vegetables) and water, or from animals and insects (Brown, 2000). Another route of transmission of the bacteria is via upper gastrointestinal endoscopy, and is currently limited in developed countries due to the use of disposable biopsy forceps and the traceability of endoscope reprocessing (Brown, 2000). In 1995, Tytgat estimated a transmission frequency of about 4 patients per 1000 endoscopies when the infection rate in the endoscopy population was about 60% (Tytgat, 1995).

Chemical ingredients used for high-level disinfection

According to the classification made by Spaulding, endoscopes are considered semi-critical instruments and must undergo high-level disinfection. Biopsy forceps (unless disposable) are considered critical devices and should be cleaned and sterilized after each use (Deyi, 2018).

In vitro Helicobacter pylori is sensitive to high-level chemical disinfectants in 15 to 30 seconds. However, a minimum of 10 minutes immersion is recommended. Cleaning with soap and water and rinsing with alcohol have been shown to be insufficient for proper disinfection of endoscopes and biopsy forceps. (Deyi, 2018)

In order to prevent the spread of healthcare-associated infections, all heat-sensitive endoscopes, such as gastrointestinal endoscopes, should be properly cleaned and subjected to high-level disinfection after each use.

Listed below are active ingredients that can be used to disinfect medical instrumentation to help prevent Helicobacter pylori infections:

  • Glutaraldehyde is a saturated dialdehyde used as a high-level disinfectant and chemical sterilant. Aqueous solutions of glutaraldehyde are acidic and thus not sporicidal. When the solution is ‘activated’ by the use of alkalizing agents at pH 7.5-8.5, the solution becomes sporicidal. It is very effective and does not damage endoscopes. (Kampf, 2018)
  • Orthophthalaldehyde(OPA) is a more stable alternative to glutaraldehyde, but is more expensive. It does not require activation, is stable over a wide pH range (3-9), has an almost imperceptible odor, and has good material compatibility. (Rutala, Weber, & (HICPAC), 2024)
  • Peracetic acid is very effective and may be a suitable alternative to glutaraldehyde or OPA. Not decomposed by peroxidases, unlike H2O2, it remains active in the presence of organic matter and is sporicidal even at low temperatures. It decomposes to oxygen, acetic acid and hydrogen peroxide (acetic acid and hydrogen peroxide are further decomposed to water, carbon dioxide and oxygen), and does not affect the environment. Peracetic acid inactivates gram-positive and gram-negative bacteria, fungi and yeasts in ≤5 minutes at <100 ppm. In the presence of organic matter, 200-500 ppm are required. For viruses, the dosing range is wide (12-2250 ppm). In combination with hydrogen peroxide it exhibits strong bactericidal activity. (Kampf, 2018)
  • Hydrogen peroxide is used as a disinfectant and sterilant. It acts on a broad microbial spectrum, with higher efficacy on gram-positive bacteria. It ensures high-level disinfection of all types of digestive endoscopes, including duodenoscopes (Molloy-Simard, Lemyre, Martel, & Catalone, 2019). Hydrogen peroxide is considered largely environmentally friendly, as it decomposes into water and oxygen (Ilias, Hocopan, Brata, & Fratila, 2023).
  • Hypochlorous acid is a weak acid obtained by electrolyzing an aqueous solution of sodium chloride in a specially designed reactor. The process of obtaining hypochlorous acid without elemental chlorine is due to the neutral pH of the process. The sodium hypochlorite solution has a weakly acidic pH which gives it an oxidizing agent character. (***, 2020) The product has a low toxicity profile, being active on a broad spectrum of microbial agents. (***, -) If the manufacturing process is not carried out properly, the product may lack storage stability, lose some of its efficacy and even be toxic.

Occupational risks for healthcare workers

A review that included 15 studies demonstrated an increased risk of Helicobacter pylori infection among medical staff in gastroenterology following endoscopy procedures (Peters, et al., 2011). Therefore, medical personnel must be regularly trained on the proper handling, cleaning, and disinfection of endoscopes to prevent healthcare-associated infections.

Hand hygiene should be performed before and after removal of personal protective equipment. During procedures and when handling possibly contaminated instruments, it is essential to wear personal protective equipment (gloves, gowns, mask and goggles). Procedures for reprocessing endoscopes should be strictly followed and the instrumentation should be inspected and maintained regularly.

Methods for reprocessing endoscopes

Manual endoscope reprocessing involves a number of steps:

  • Pre-cleaning: contamination of endoscopes and biopsy forceps with Helicobacter pylori occurs immediately after endoscopic examination of positive patients. Therefore, immediately rinse the endoscope with water to remove any visible debris of organic matter. Inspect the endoscope for damage or defects.
  • Manual cleaning: Use an enzymatic detergent to clean the endoscope, paying particular attention to the channels, valves and other component parts. Brush the channels using specialized brushes and rinse thoroughly with water.
  • High-level disinfection: Immerse the endoscope in a high-level disinfectant solution, following the manufacturer’s instructions about the correct concentration and exposure time.
  • Rinsing: Rinse the endoscope and all channels with sterile water, preferably to remove all traces of disinfectant. If tap water is used, it is recommended to rinse the outer surface as well as all channels with 70% – 90% alcohol and dry them completely with compressed air.
  • Drying: This is essential to prevent reinfection.
  • Storage: Store the endoscope in a clean, dry and well-ventilated area to prevent recontamination.

The advantages of the manual method of cleaning and disinfection are: adaptability (staff can adjust the technique according to the condition of the endoscope), they can quickly identify if there is damage and act accordingly, and the initial outlay is lower.

The disadvantages are: longer reprocessing time, increased exposure to chemicals and the possibility of human error.

In a study of 400 patients undergoing upper gastrointestinal endoscopy for routine clinical indications, 128 were found positive for Helicobacter pylori. Endoscopes were contaminated in 54 of the 128 samples used in positive patients (42%) before cleaning and disinfection. One of the 128 samples (0.8 %) was found to be contaminated even after routine manual cleaning and disinfection, which indicated that these procedures may be insufficient to completely eradicate the bacteria, especially when not performed correctly (Nürnberg, Schulz, Rüden, & Vogt, 2003).

Therefore, the use of automated endoscope reprocessing systems is a better option. They are suitable for both flexible and rigid ones.

The benefits of using such a system are listed below (***, 5 Benefits of Automated Endoscope Reprocessing, 2019):

Patient safety

In manual cleaning and disinfection, if the steps are not followed exactly, in addition to the pathogens not being eliminated and being passed on, the safety of the next patient may be jeopardized by exposure to disinfectants. In the case of insufficient rinsing, problems such as chemical colitis, keratopathy or corneal damage may occur.

Staff safety

With the use of an automated endoscope reprocessing system, staff are no longer exposed to chemicals whose handling can have adverse health effects.

Process standardization

The use of an automated endoscope reprocessing system ensures compliance with established cleaning and disinfection procedures and minimizes human error.

Plant productivity

With process automation, reprocessing time decreases and process efficiency increases.

Profitability

As productivity increases, more instruments can be reprocessed each day, thus increasing profitability. Endoscopes deteriorate 18% of the time when handled and an automated reprocessing system reduces handling by 34%. This reduces damage and the need for repairs, saving money, which is very important in healthcare.

Traceability

Information such as date, sterilization time, endoscope serial number, batch of substances, recording the details of each cycle, which can be essential for compliance and quality control purposes, is permanently secured.

Disadvantages include: high investment and maintenance costs, the risk of staff becoming too dependent on the automated system and neglecting critical pre-cleaning steps or visual inspections.

Recognizing that each method has advantages and disadvantages, many institutions have adopted a hybrid approach that combines the adaptability and immediate quality checks of the manual method with the consistency and efficiency of automated reprocessing systems (Chotia, -).

Whichever cleaning and disinfection method is chosen, regular training, quality controls and periodic protocol reviews ensure efficient reprocessing of endoscopes, thereby reducing the risk of healthcare-associated infections. This ensures the highest standards of patient safety and care.

Sources:

***. (-). Retrieved from https://www.aqualution.co.uk/leaders/hypochlorous-acid-faqs/

***. (2019). Retrieved from https://censis.com/blog/automated-endoscope-reprocessing-5-benefits

***. (2020). Regulation (EU) No 528/2012 concerning the making available on the market and use of biocidal products – Active chlorine released from hypochlorous acid Product-type 2 (Disinfectants and algaecides not intended for direct application to humans or animals).

Brown, L. M. (2000) Helicobacter pylori: Epidemiology and Routes of Transmission. Epidemiologic Reviews, 22, 291.

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Molloy-Simard, V., Lemyre, J., Martel, K., & Catalone, B. (2019). Elevating the Standard of Endoscope Processing: Terminal Sterilizationof Duodenoscopes Using a Hydrogen Peroxide-Ozone Sterilizer. American Journal of Infection Control.

Nürnberg, M., Schulz, H. J., Rüden, H., & Vogt, K. (2003). Do Conventional Cleaning and Disinfection Techniques Avoid the Risk of Endoscopic Helicobacter pylori Transmission? Endoscopy.

Peters, C., Schablon, A., Harling, M., Wohlert, C., Costa, J. T., & Nienhaus, A. (2011). BMC Infectious Diseases.

Rutala, W. A., Weber, D. J., & (HICPAC), T. H. (2024).

Sakudo, A., Miyagi, H., Horikawa, T., Yamashiro, R., & Misawa, T. (2018). Treatment of Helicobacter pylori with dielectric barrier discharge plasma causes UV induced damage to genomic DNA leading to cell death. Chemosphere, 366-372.

Tytgat, G. N. (1995). Endoscopic transmission of Helicobacter pylori. Alimentary Pharmacology and Therapeutics.