Cholera | 27 Jul 2022

Researchers identified the decline of antimicrobial resistance in Cholera-Causing Bacteria.

More than two hundred serogroups of Cholera bacterium are known, of which only O1 and O139 Genomes are known to cause such infection that leads to epidemics and pandemics.
- Researchers studied the genome of O139 and traced the reason for its dying down after taking over from O1.
Two key genomic evolutionary changes took place in O139, the first related to the type of cholera toxin it produced and the second related to a loss of Antimicrobial Resistance (AMR).
Two main modifications were in the cholera toxin genes and in the Antimicrobial Resistance (AMR) portfolio.
With the reduction in AMR capacity of O139, it potentially lost its competitive advantage against the O1.

About:
- It is a life-threatening infectious disease and a public health hazard.
- Cholera is an acute, diarrheal illness caused by infection of the intestine with the bacterium Vibrio cholerae.
- The infection is often mild or without symptoms, but sometimes can be severe.
Symptoms:
- Profuse watery diarrhoea
- Vomiting
- Leg cramps
Transmission:
- A person may get cholera by drinking water or eating food contaminated with the cholera bacterium.
- The disease can spread rapidly in areas with inadequate treatment of sewage and drinking water.
Vaccine:
- Currently there are three WHO pre-qualified oral cholera vaccines (OCV), Dukoral, Shanchol, and Euvichol-Plus.
- All three vaccines require two doses for full protection.

Continuous surveillance is necessary to monitor if any of the serotypes and serogroups are gaining antibiotic resistance over time and may become major outbreak lineages at any time.
To stay ahead of the curve and ensure best public health outcome, it is important that vaccines and treatments are regularly re-evaluated for efficiency to any newly evolving variants.