22 February 2018

The recent spread of drug resistant strain of Typhoid is due to Salmonella enterica serovar Typhi (H58) that is a human-restricted bacterial pathogen responsible for causing an estimated 27 million cases of typhoid fever annually, leading to 217,000 deaths, and current vaccines do not offer full protection.

Researchers from Britain’s Wellcome Sanger Institute who analysed the genetics of the typhoid strain found it had mutated and acquired an extra piece of DNA to become resistant to multiple antibiotics.

According to experts, drug-resistant typhoid is still spreading that began in Hyderabad since November 2016. Official data on case numbers and deaths are not available, but local media reports say health authorities detected more than 800 cases of drug-resistant typhoid in Hyderabad alone in a 10-month period between 2016 and 2017.

This strain emerged from South Asia around 25-30 years ago and has grown to become one of the predominant forms of the bacteria, according to the author of the study, Vanessa Wong, who is a microbiologist at the University of Cambridge in England. Ms. Wong stated, “This multi-drug-resistant strain, H58, is resistant to a number of first-line antibiotics used to treat the disease and is continuing to evolve and acquire new mutations to newer drugs.”

The reason for this is said to be due to unwarranted use of antibiotics sometimes even without prescription. In Pakistan, antibiotics can easily be purchased from pharmacies without any valid prescription. While 70 to 80 percent of diarrhea is caused by viral pathogens, for which antibiotics are not effective, around 40 percent of these cases are nevertheless attempted to be treated with antibiotics. In some areas even over 80 percent of cases are attempted to be treated with antibiotics.

Instead of antibiotics, vaccines should be the first line of defense for preventing any disease. However, as Vanessa Wong points out, “Vaccinations are not currently in widespread use in typhoid-endemic countries. Instead, antibiotics are commonly used as a preventive measure. As a consequence, there is a rise in antibiotic resistance to many pathogens and in particular a resurgence of multi-drug-resistant typhoid has been observed in some areas, including parts of Africa.”

There are two vaccines to prevent typhoid. One is an inactivated vaccine gotten as a shot, and the other is live, attenuated vaccine, which is taken orally. The vaccine given as a shot is the one that is commonly used in Pakistan. The earliest that this vaccine can be given is at two years of age. While a single dose is protective, the protection only lasts around two years, after which time the vaccine dose may need to be repeated. The vaccine is 50-80% effective against all strains of typhoid, even those that have become antibiotic-resistant.

Reduced susceptibility to ciprofloxacin and the emergence of multi-drug-resistance has complicated treatment of infections, particularly those acquired in South Asia. Choices for antibiotic therapy include fluoroquinolones, azithromycin, and ceftriaxone. People who do not receive treatment might continue to experience a fever for weeks or months; as many as 20% could die from complications of the infection.

Even if a person’s symptoms seem to disappear, they might still be carrying Salmonella Typhi. The symptoms of typhoid include headache, weakness, stomach pains, loss of appetite and high fever.

If this is the case the illness could return, or the person could pass the disease along to others. If you are treated for typhoid fever it is important to continue taking the antibiotics prescribed for you for as long as your doctor asks you to take them. Wash your hands carefully with soap and water after using the bathroom and do not prepare or serve food or beverages for other people. Doing so will decrease the chance that you will pass the infection along to someone else.

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