PREVALENCE AND ANTIMICROBIAL RESISTANCE PATTERNS OF SALMONELLA TYPHI ISOLATED FROM HUMAN PATIENTS

Abstract

Salmonella Typhi (S. Typhi) is the pathogen that causes typhoid fever, one of the most significant health-related problems, particularly in regions with inadequately sanitized and limited access to clean water. The emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) S. Typhi strains has made disease management and treatment outcomes even more difficult. The research aimed to determine the occurrence and distribution of antimicrobial resistance of S. Typhi in human blood. 120 blood samples were collected from suspected typhoid patients aged 5-40 years across different hospitals and clinics. Blood culture was positive in 70 cases (58%), and the most common age group was 11-30 years. The modified Kirby-Bauer disc diffusion method according to CLSI was used to test the antimicrobial susceptibility of 14 S. Typhi isolates. Results showed that 28.6% were MDR, i.e., resistant to the first-line agents (trimethoprim-sulfamethoxazole, ampicillin, or tetracycline), 50% were XDR, resistant to the first- as well as second-generation agents (fluoroquinolones and 3rd-generation cephalosporins), and 3% were multidrug-resistant, i.e., resistant to all first-, second-, and third-generation agents. It is important to note that 21.4 percent of the isolates exhibited abnormal antibiogram patterns, which showed resistance to almost all the antibiotics tested, including azithromycin and carbapenems. Age analysis showed that MDR was dominant in the 5-15 years age and XDR was dominant in the 11-20 years age group and affected both genders. These results demonstrate that there is a pressing necessity to conduct continuous antimicrobial surveillance, address the rational use of antibiotics, enhance sanitation, and mass vaccination to curb the dissemination of highly resistant S. Typhi strains and avoid untreatable typhoid infections.