Changing Resistance Pattern and Emerging Salmonella Paratyphi A Enteric Fever – New Challenges and New Trends: A Study from Tertiary Care Medical College and Hospital in North India

ABSTRACT

Background: Enteric fever or Typhoid fever is caused mostlyby Salmonella enterica serovar Typhi and Salmonella entericaserovar Paratyphi is an important public health challenge forIndia, especially with the spread of antimicrobial resistance.The situation is further complicated by increased incidence insome parts of the country of S. Paratyphi A as a cause ofenteric fever. This serovar is not prevented by currentlyavailable typhoid vaccines and represents an increasing threatto human health.Purpose: The present study was undertaken to analyse thetrend in prevalence of culture-positive typhoid fever during thelast three years and to determine antimicrobial susceptibilityprofile of Salmonella Typhi and Salmonella Paratyphi Aisolated from patients of enteric fever in this part of the country.Material: This retrospective study incorporates a three years,(January 2015-December2018) laboratory data comprising52isolates of Salmonella. Cultures were identified by standardmethods. Antimicrobial susceptibility was done againstchloramphenicol, amoxicillin, co-trimoxazole, ciprofloxacin,ceftriaxone, cefixime and azithromycin as per correspondingCLSI guidelines for each year.Results: Salmonella enterica serotype Typhi (S. Typhi) wasthe more frequent serotype isolated i.e., 73% with theremaining 27% being Salmonella enterica serotype Paratyphi A(S. Paratyphi A). There was emergence of S. Paratyphi Aserotype in 2017-18. Antimicrobial susceptibility forchloramphenicol, amoxicillin and co-trimoxazole, ciprofloxacinand ceftriaxone was found to be 97.2%, 88.5%, 90.5%, 66.8%,99.4% for S. Typhi and 100%, 90.1% and 92.8%, 71.5%, 100%for S. Paratyphi A.Conclusion: The present study confers Salmonella ParatyphiA as the rapidly emerging pathogen of enteric fever. Theantibiogram of Salmonella Typhi and Salmonella Paratyphi Ashowed decreased susceptibility to fluoroquinolones and anotable decrease in the multi drug resistant strains ofSalmonella isolates with re-emergence of susceptibility to firstline antibiotics.