Background
Cholera, is an acute diarrheal disease caused by infection of the small intestine through certain pathogenic strains of Vibrio cholerae1. Cholera usually develops immediately after exposure to the pathogen, and symptoms can be either mild or quite severe2. The typical symptom of cholera is severe watery diarrhea for several consecutive days, which may be accompanied by vomiting and muscle twitching. The severe diarrhea can result in dehydration, electrolyte imbalances and even death, or sunken eye sockets, clammy and inflexible skin, cyanosis, and wrinkles on hands and feet2-5.
With the development of society, public health and water quality have been significantly improved, though the disease still kills about 100,000 people worldwide every year.
Vibrio cholerae
Vibrio cholerae is pathogenof human cholera. At present, more than 200 species of Vibrio cholerae have been identified according to the variation of O-antigen, among which group O1 and O139 can cause cholera. Vibrio cholerae is a Gram-negative bacteria which is sensitive to drying, sunlight, heat, acid and general disinfectants6. Normal gastric acid can kill Vibrio. When gastric acid is temporarily low or the number of invading virus bacteria increases, Vibrio that is not killed by gastric acid enters the small intestine, multiply rapidly in alkaline intestinal fluid, and produce a large amount of strong exotoxin.
The action of this exotoxin on the small intestinal mucosa can cause a large secretion of intestinal fluid, even exceeding the reabsorption capacity of the intestinal tract. Clinically, severe diarrhea and vomiting, severe dehydration, resulting in significantly reduced plasma volume, lack of salt in the body, blood concentration, and peripheral circulatory failure.
Popularity and Transmission Mechanisms
Earth water environment studies have confirmed that Vibrio cholerae (including O1, O139 Vibrio cholerae) is a part of the normal habitat and ecology of surface water (especially salt water), and the natural source of Vibrio cholerae is the water environment, through and plankton (The symbiotic relationship of copepods, crustaceans, algae, etc.) enables long-term survival and reproduction without loss of virulence7-10.
Patients and carriers are the source of infection for cholera, contaminating the environment through continuous faecal excretion. The patient's daily excretion of bacteria is larger, and the carrier's fecal bacteria content is lower. Water-borne, food-borne or close contact transmission can occur after the feces of patients and carriers contaminate water, food, and the environment. Bacteria or contamination of surface water, sea and aquatic products are the main vectors of cholera transmission11.
Common detection methods
For the examination of cholera patients, in addition to routine blood, urine and serum tests to assist in the diagnosis, the most important thing is to check the pathogenic bacteria12.
The clinical detection methods for Vibrio cholerae now include molecular biological detection and microbiological detection.
Molecular biological detection
Polymerase Chain Reaction (PCR)
In recent years, the use of PCR to diagnose cholera has become more and more widespread. The toxin gene subunit CtxA and toxin-cooperating fimbriae gene (TcpA) of Vibrio cholerae are identified by qPCR technology to distinguish cholera strains from non-cholera vibrio. The test results can be obtained within 4 hours, and the purpose of efficiently detecting Vibrio cholerae is achieved.
PCR detection of Vibrio cholerae is not only highly specific, but also simple, rapid and sensitive, which can greatly improve the detection rate and ensure that patients can receive timely and accurate treatment plans.
Gene Chip
Gene chip, also known as "biochip", can be divided into protein chip, carbohydrate chip and gene chip according to the types of molecular probes immobilized on the substrate. In particular, gene chips have become an important analytical tool for current biological detection, and they are all based on the specific hybridization between nucleic acid probes and their complementary targets to form stable duplexes or triplexes.
A gene chip consisting of thousands of functionalized probes immobilized on a solid substrate is a comprehensive analytical device that has been introduced into many fields such as biochemistry and medical diagnosis, and provides accurate, high-throughput compared to PCR parallel analysis.
Loop-mediated Isothermal Amplification (LAMP)
LAMP is another variant of the nucleic acid-based assay developed by Notomi et al. Unique to this method, amplification is performed under isothermal conditions at 60 – 65 ℃, thus omitting the need for a thermal cycler. Compared to other PCR detection methods, LAMP has been shown to be more specific and sensitive. Using LAMP to detect the ctxA gene of Vibrio cholerae, the lowest detection limit reached 1.4 CFU per reaction, which is nearly 10 times higher than that of ordinary PCR, indicating that the method has high sensitivity. Likewise, this technique has been developed to detect the V. parahaemolyticus TLH and groEL genes in various seafood.
Microbiological detection
Bacterial Culture
All suspected cholera patients left feces before antibiotics and sent them to the laboratory for training as soon as possible. Bacterial membranes can be formed on the surface after 6 - 8 h incubation in alkaline peptone water at 36 - 37 ℃. The biofilm is further separated and cultured, and then dynamic observation and braking test are carried out.
Although the sensitivity and specificity of microbiological detection are good, it is easily affected by the environment, culture conditions, and subjective factors of operators, and it takes a long time, which cannot meet the needs of a rapid response system for disease prevention and control, and is not conducive to rapid clinical diagnosis.
Vazyme’s Solutions
As a supplier of professional reagents and solutions in the fields of life science, IVD and biomedicine, Vazyme will give full play to our advantages to provide you with the extraction and amplification reagents required for product development in the field of Vibrio cholerae diagnosis, and help you quickly complete product development.
Nucleic Acid Extraction (click on the Cat.No. to see the detail of each product)
| Series | Cat.No. | Name | Samples | Details |
| Column | DC502 | FastPure Microbiome DNA Isolation Kit | Blood, swab, sputum, bronchoalveolar lavage fluid and other biological fluid samples. |
Ultra-fast extraction: only 23 minutes; |
| DC112 | FastPure® Blood/Cell/Tissue/Bacteria DNA Isolation Mini Kit | Whole blood, serum, plasma, cells, tissues, bacteria, etc. |
Compatible with multiple sample types; |
Nucleic Acid Amplification (click on the Cat.No. to see the detail of each product)
| Series | Cat.No. | Name | Samples |
| Hot-start Taq DNA Polymerase | P401-MD1 | AceTaq® DNA Polymerase |
Chemical modification, high specificity; |
| P122-MD2 | Champagne Taq™ DNA Polymerase | Antibody method modification, good adaptability and high sensitivity | |
| PN102 | Taq Pro HS Polymerase for ddPCR |
A new generation of hot-start DNA polymerase with stronger template affinity; |
|
| P132 | Taq HS DNA Polymerase |
Antibody method modification; |
|
| Heat Labile UDG | P051 | Heat-labile UDG |
Rapid inactivation at 55°C for 10 min; |
| Bst DNA Polymerase | P703 | Bst II Pro DNA Polymerase Large Fragment |
Set up the system at room temperature; |
| qPCR mix | Q513 | AceQ® Universal U+ Probe Master Mix V2 |
Platform general anti-pollution probe detection reagent; |
| QN213 | Taq Pro U+ Multiple Probe qPCR Mix |
Ultra-sensitive qPCR master mix with wide compatibility and rapid detection; |
|
| Q113 | AceQ® U+ Probe Master Mix |
Highly specific probe method detection kit; |
Reference
1. Finkelstein, R. A. (1996). Cholera, Vibrio cholerae O1 and O139, and other pathogenic vibrios. Medical Microbiology. 4th edition.
2. Cholera - Vibrio Cholerae Infection Information for Public Health & Medical Professionals. (2015, February 6). Centers for Disease Control and Prevention. https://www.cdc.gov/cholera/healthprofessionals.html
3. World Health Organization. (2010). Cholera vaccines: WHO position paper. Weekly Epidemiological Record= Relevé épidémiologique hebdomadaire, 85(13), 117-128.
4. Harris, J. B., Larocque, R. C., Qadri, F., Ryan, E. T., & Calderwood, S. B. (2012, June 30). Cholera. Lancet. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(12)60436-X/fulltext#%20
5. Diane, B. (2011, July). Cholera. Internet Archive. https://archive.org/details/cholera0000bail_d9c3
6. Yamasaki, S., Garg, S., Nair, G. B., & Takeda, Y. (1999). Distribution of Vibrio cholerae O1 antigen biosynthesis genes among O139 and other non-O1 serogroups of Vibrio cholerae. FEMS microbiology letters, 179(1), 115-121.
7. Collins, A. E. (2003). Vulnerability to coastal cholera ecology. Social Science & Medicine, 57(8), 1397-1407.
8. Colwell, R. R. (1996). Global climate and infectious disease: the cholera paradigm. Science, 274(5295), 2025-2031.
9. Huq, A., Sack, R. B., Nizam, A., Longini, I. M., Nair, G. B., Ali, A., ... & Colwell, R. R. (2005). Critical factors influencing the occurrence of Vibrio cholerae in the environment of Bangladesh. Applied and environmental microbiology, 71(8), 4645-4654.
10. Koelle, K. (2009). The impact of climate on the disease dynamics of cholera. Clinical microbiology and infection, 15, 29-31.
11. Sack, D. A. (2004, January 17). Cholera. Lancet. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(03)15328-7/fulltext
12. Larocque, R., & Harris, J. B. (2022, March 22). Cholera: Clinical Features, Diagnosis, Treatment, and Prevention. UpToDate. https://www.uptodate.com/contents/cholera-clinical-features-diagnosis-treatment-and-prevention/print
