Guangzhou Institute of Biology and others proposed a high-sensitivity and high-precision detection method for Helicobacter pylori

Li Zhiyuan's team from Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, combined with the latest CRISPR/Cas12a technology through ring-mediated isothermal amplification (LAMP), proposed a high-sensitivity detection method
for highly pathogenic Helicobacter pylori strains.
This method only needs to test a saliva sample, which can quickly and accurately detect positive patients
infected with this strain.
Recently, Harnessing enhanced CRISPR/Cas12a trans-cleavage activity with extended reporters and reductants for early diagnosis of Helicobacter pylori, the causative agent of peptic ulcers and stomach cancer, published in
Biosensors and Bioelectronics.

Helicobacter pylori infection is the main causative factor of chronic gastritis and peptic ulcer, and is closely related
to gastric cancer and gastric mucosa-associated lymphoid tissue (MALT) lymphoma.
Most patients with Helicobacter pylori infection can be cured with multiple therapies according to the doctor's advice, but most infected patients are almost asymptomatic in the early stage and are easy to be ignored
.
In addition, not all people with Helicobacter pylori infection develop the disease, and strains with cytotoxin-associated protein (CagA) and vacuolar toxin (VacA) expression are the ones associated with gastric inflammation, ulceration, and gastric cancer
.
Therefore, there is an urgent clinical need for rapid, accurate, highly specific and sensitive on-site detection methods to help prevent the spread of highly pathogenic Helicobacter pylori and real-time monitoring and diagnosis
of already ill people.

At present, clinical H.
pylori detection methods mainly rely on histology or Helicobacter pylori culture, UBT (13C or 14C-urea breath test), and serological testing, but these methods have obvious shortcomings that affect their popularization
.
In contrast, the ring-mediated isothermal amplification (LAMP) technique used by Li's team has been shown to be more sensitive (100 times) than PCR, and the test results
can be obtained quickly using a simple water bath at a constant temperature (65°C).
In addition, studies have shown that the combination of CRISPR/Cas technology can further improve its detection sensitivity and reduce non-specific amplification
.
Specifically, this method significantly improves the backcut activity of LbCas12a by a novel optimized extension of ssDNA reporter and a novel buffer system to optimize CEXTRAR, and improves the detection sensitivity by a factor of 16, while achieving picomolar sensitivity without target preamplification, which can be used for the early detection
of highly pathogenic Helicobacter pylori in clinical saliva samples 。 Combined with LAMP technology, CEXTRAR can obtain extremely sensitive detection of CagA and VacA using three detection methods: real-time fluorescence (43 aM and 96 aM), in-tube fluorescence (430 aM and 960 aM), and lateral lateral flow readings (4.
3 aM and 9.
6 aM),
respectively.
The CEXTRAR method was compared with the traditional 13C-urea breath test and PCR, and CEXTRAR was found to detect false-negative results
of the 13C urea breath test.

Compared with the traditional Helicobacter pylori detection method, this method has the characteristics of simpler, faster and cheaper, and has higher sensitivity and specificity, and will play an important role
in the detection and treatment of highly pathogenic Helicobacter pylori in the general population and the occurrence and improvement of prognosis of related diseases such as gastritis, gastric ulcer and gastric cancer.

The research work is supported
by the Natural Science Foundation of Guangdong Province and the Key R&D Program of Hunan Province.
Researchers from Dongguan Hospital affiliated to Southern Medical University participated in the research
.

Schematic of the operation of the CEXTRAR platform for real-time fluorescence and colorimetric monitoring of Helicobacter pylori