KEY POINTS-

• The effectiveness of antibiotics for typhoid fever is threatened by the emergence of resistant strains.
• Large genome sequencing study of bacteria, Salmonella typhi was undergone showing the resistant strains.
• Typhoid fever causes 11 million infections and more than 100,000 deaths per year.
• Since 2000, multi-drug-resistant(MDR) S Typhi has declined steadily.
• They are replaced by strains resistant to other antibiotics.
• The genome analysis also reveals that resistant strains have spread to 197 countries since 1990.
• The study sequenced 3,489 S typhi isolates from 2014-19, collecting 4,169 samples isolated from 70 countries during 1905-2018.

ANTIBIOTICS -

• Strains were classified as MDR if they had genes giving resistance to antibiotics like ampicillin, chloramphenicol and trimethoprim/sulfamethoxazole.
• Certain strains were observed where the single oral antibiotic is effective termed as XDR-typhoid.
• Strains resistant to the antibiotic (azithromycin) were seen in INIDA, Bangladesh, Pakistan and Nepal.
• Researches suggest that much of the drug resistance in typhoid has evolved in India, so it is concerned about the appearance of drug resistance.
• India's Health Ministry is considering to introduce new conjugate vaccines into the national immunization program.
• WHO-prequalified vaccines have been developed in India by Bharat Biotech and Biological E.
• During 2016-20, typhoid was as common as it was 2 decades ago, especially in urban areas.

EPILOGUE-