Context:

Researchers at the Council of Scientific and Industrial Research–Institute of Genomics and Integrative Biology (CSIR–IGIB) have found a way to develop a CRISPR-based FELUDA diagnostic method for detecting H. pylori and its clarithromycin resistance mutations. 

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H. pylori infections affect 43% of the global population, leading to gastrointestinal disorders like peptic ulcers, gastritis, dyspepsia, and gastric cancer.

Resistance to clarithromycin due to mutations in the 23S ribosomal RNA coding gene of H. pylori, poses a significant public health challenge.

• Clarithromycin is a semisynthetic macrolide antibiotic used for a wide variety of mild-to-moderate bacterial infections such as acute otitis, pharyngitis, tonsillitis, respiratory tract infections, uncomplicated skin infections, and helicobacter pylori infection. 

Therefore, development of cost-effective diagnostic tools to detect H. pylori and determine antibiotic susceptibility is essential for its effective and timely eradication.

Study Highlights 

• The system uses an engineered Cas9 protein (en31-FnCas9) to successfully detect the presence and identify the 23S rDNA mutations in gastric biopsy samples from dyspeptic Indian patients using in vitro cleavage and lateral flow-based assays (FELUDA).
• The integration of en31-FnCas9-based detection with the lateral flow assay (FELUDA) provides a rapid visual readout of H. pylori infection and mutation status, enhancing clinical diagnostic efficiency.
• This marks the first report of en31-FnCas9-mediated molecular diagnosis targeting clarithromycin resistance mutations in H. pylori. 

Advantages of the Method

• Sequencing-Free: Does not require advanced genetic sequencing tools.
• Cost-Effective: Affordable and accessible for resource-poor settings.
• Rapid Results: Provides quick and accurate diagnosis for clinicians.
• Targeted Treatment: Enables personalized therapeutic strategies, reducing antibiotic resistance risks.

About Helicobacter Pylori (H. pylori) 

H. pylori is a type of bacteria that infects the stomach lining. It's a common cause of various gastrointestinal disorders.

Gastrointestinal Disorders Associated with H. pylori

1. Peptic Ulcers: Open sores in the lining of the stomach or the upper part of the small intestine.

2. Gastritis: Inflammation of the stomach lining. 

3. Dyspepsia: Indigestion with symptoms like bloating, belching, and stomach discomfort.

4. Gastric Cancer: Long-term infection with H. pylori can increase the risk of developing stomach cancer.

H. pylori Infection: 

• Transmission: Spread through contaminated food, water, or close contact with an infected person.
• Symptoms: Often asymptomatic, but symptomatic cases can cause stomach pain, nausea, bloating, and loss of appetite.
• Diagnosis: Common diagnostic methods include breath tests (urea breath test), stool antigen tests, serology (blood tests), and endoscopy with biopsy for more definitive diagnosis.
• Treatment: Typically involves a combination of antibiotics (e.g., clarithromycin, amoxicillin) to eradicate the bacteria. 

What is Feluda test?

The FnCas9 Editor Linked Uniform Detection Assay (Feluda) test is a rapid diagnostic test for COVID-19 developed by the Council of Scientific and Industrial Research's Institute of Genomics and Integrative Biology (CSIR-IGIB) in India. 

Key Features

• The test utilizes CRISPR-Cas9 technology, specifically the FnCas9 protein, to detect the presence of SARS-CoV-2 viral RNA.
• Similar to a pregnancy test, it uses a paper strip that changes colour to indicate a positive or negative result. 

What is CRISPR-Cas9?

• A revolutionary gene-editing tool derived from bacterial immune systems.
• CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) is a DNA sequence guiding Cas9, a specialized protein, to target and cut specific DNA sequences with high precision.