Changing Pattern of Resistance in Typhoid Fever in An Era of Antimicrobial Resistance: Is It Time to Revisit Treatment Strategies?

Objectives: Multi-drug-resistant Salmonella Typhi is a major concern in the current era of antimicrobial resistance. The emergence of ceftriaxone-resistant Salmonella Typhi strains (CRST) has left very few therapeutic options for the treatment of these infections. The objective of this study was to evaluate the typhoid cases diagnosed with CRST and retrospectively analyze the antimicrobial sensitivity pattern of Salmonella Typhi over the past three years. Methods: Laboratory data from our hospital were reviewed for the past three years to examine the trends related to the isolation of Salmonella Typhi from blood and their antimicrobial susceptibility. The case records from the patients whose blood culture detected Ceftriaxone resistant Salmonella Typhi (CRST) were reviewed to assess the clinical condition and outcome. Results: Analysis of the antimicrobial susceptibility of Salmonella Typhi showed a decline in multidrug-resistant strains. Nalidixic acid resistance has remained high during this period. The resistance to ceftriaxone has shown an increase from 0% in 2016 to 11(12.6%) isolates in 2018. Also, azithromycin resistance has shown a steady increase from 0% in 2016, 3 (3.2%) in 2017 to 7 (8.5%) in 2018. There was no clustering of cases by time or space indicating a non-outbreak spread of ceftriaxone resistant strains. Conclusion: Development of resistance to ceftriaxone and azithromycin necessitates revision of therapeutic choices. All this necessitates an approach to do further extensive surveillance at the community level and improvement in hygiene, sanitation, and drinking water supply. Maybe it is time to revisit the older antibiotics such as ampicillin, cotrimoxazole, and chloramphenicol as therapeutic options for uncomplicated typhoid fever. J Microbiol Infect Dis 2021; 11(1):1-7.