How can the transmission of Helicobacter pylori via endoscopy be prevented?

Helicobacter pylori infection is recognized as one of the most widespread globally, being a major cause of morbidity and mortality. The transmission of the bacterium 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 primarily 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 stomach infection worldwide, following which a portion of the population develops symptoms of dyspepsia with a diagnosis of gastritis or peptic ulcer, and another portion develops preneoplastic lesions or neoplasms (intestinal-type gastric adenocarcinoma 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 the infection varies greatly depending on 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 the Helicobacter pylori bacterium is not fully known. It can be transmitted from person to person (oral-oral, gastro-oral, fecal-oral routes, through breastfeeding), but also through the consumption of food (especially raw vegetables) and contaminated water, or via animals and insects (Brown, 2000). Another route of transmission of the bacterium is through upper gastrointestinal endoscopy, which is currently limited in developed countries due to the use of single-use biopsy forceps and the traceability of endoscope reprocessing (Brown, 2000). In 1995, Tytgat estimated a transmission frequency of approximately 4 patients per 1000 endoscopies when the infection rate in the endoscoped population was approximately 60% (Tytgat, 1995).

Chemical ingredients used for high-level disinfection

According to the Spaulding classification, endoscopes are considered semi-critical instruments and must undergo high-level disinfection. Biopsy forceps (if not single-use) are considered critical devices and must be cleaned and sterilized after each use (Deyi, 2018).

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

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

Below are the active ingredients that can be used for the disinfection of medical instruments, with a role in preventing Helicobacter pylori infections:

• Glutaraldehyde is a saturated dialdehyde used as a high-level disinfectant and chemical sterilant. Aqueous glutaraldehyde solutions are acidic and therefore not sporicidal. When the solution is "activated" using alkalizing agents at a pH of 7.5–8.5, the solution becomes sporicidal. It is highly effective and does not damage endoscopes (Kampf, 2018).

• Ortho-phthalaldehyde (OPA) is a more stable alternative to glutaraldehyde, but it 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 can be a suitable alternative to glutaraldehyde or OPA. As it is not broken down by peroxidases, unlike H₂O₂, it remains active in the presence of organic matter and is sporicidal even at low temperatures. It decomposes into oxygen, acetic acid, and hydrogen peroxide (acetic acid and hydrogen peroxide are further broken down into water, carbon dioxide, and oxygen), not affecting 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 dosage range is wide (12–2250 ppm). In combination with hydrogen peroxide, it shows strong bactericidal activity (Kampf, 2018).

• Hydrogen peroxide is used as a disinfectant and sterilant. It acts on a broad microbial spectrum, having greater efficacy against 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 largely considered environmentally friendly, as it decomposes into water and oxygen (Ilias, Hocopan, Brata, & Fratila, 2023).

• Hypochlorous acid is a weak acid obtained through the electrolysis of an aqueous sodium chloride solution in a specially designed reactor. The process of obtaining hypochlorous acid without elemental chlorine is due to the neutral pH of the process. Sodium hypochlorite solution has a slightly acidic pH that gives it the character of an oxidizing agent (***, 2020). The product has a low toxicity profile and is active against 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 medical staff

An analysis that included 15 studies demonstrated an increased risk of Helicobacter pylori infection among medical staff in the gastroenterology department following the performance of endoscopy procedures (Peters et al., 2011). Therefore, it is important for medical staff to be trained periodically on the proper handling, cleaning, and disinfection of endoscopes to prevent healthcare-associated infections.

Hand hygiene must be performed before and after removing personal protective equipment. During procedures and when handling potentially contaminated instruments, wearing personal protective equipment (gloves, gowns, mask, and goggles) is essential. Endoscope reprocessing procedures must be strictly followed, and instruments must be regularly inspected and maintained.

Endoscope reprocessing methods

Manual reprocessing of the endoscope involves a series of steps:

• Pre-cleaning: Contamination of endoscopes and biopsy forceps with Helicobacter pylori occurs immediately after endoscopic examination of positive patients. Therefore, rinse the endoscope immediately with water to remove any visible organic matter residues. Inspect the endoscope for damage or defects.

• Manual cleaning: Use an enzymatic detergent to clean the endoscope, paying special attention to channels, valves, and other components. Brush the channels using specialized brushes and rinse them thoroughly with water.

• High-level disinfection: Immerse the endoscope in a high-level disinfectant solution, following the manufacturer's instructions regarding the correct concentration and exposure time.

• Rinsing: Rinse the endoscope and all channels with sterile water, preferably, to remove any trace 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 an essential step to prevent re-infection.

• Storage: Keep the endoscope in a clean, dry, and well-ventilated area to prevent recontamination.

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

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

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

Therefore, using automated endoscope reprocessors is a better option. They are suitable for both flexible and rigid endoscopes.

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

Patient safety

In the case of manual cleaning and disinfection, if the steps are not strictly followed, besides the fact that pathogens are not eliminated and are transmitted further, the safety of the next patient may be endangered 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 negative health effects.

Process standardization

By using an automated endoscope reprocessing system, compliance with established cleaning and disinfection procedures is ensured, minimizing human errors.

Facility productivity

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

Profitability

Given that productivity increases, more instruments can be reprocessed every day, thus increasing profitability. Endoscopes are damaged in 18% of cases when handled, and an automated reprocessing system reduces their handling by 34%. Thus, damage and the need for repairs are reduced, saving money, which is a very important aspect in the medical system.

Traceability

Information such as date, sterilization duration, endoscope serial number, and substance batch are always ensured, recording the details of each cycle, which can be essential for compliance and quality control purposes.

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

Given 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, -).

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

Bibliography

***. (-). 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).

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