Antimicrobial susceptibility trend among enteric fever isolates in a tertiary care hospital of Coastal Karnataka, India

Background: Enteric fever due to Salmonella typhi (S. typhi) and Salmonella paratyphi A (S. paratyphi A) is one of the significant public health problems worldwide. Aim and Objectives: To determine the antibiotic susceptibility pattern of Enteric fever isolates to first-line drugs as well as other drugs such as ciprofloxacin, ceftriaxone, and azithromycin. Nalidixic acid as a surrogate marker was reviewed. Material and Methods: A total of 80 isolates were tested for antimicrobial susceptibility using Kirby Bauer disc diffusion method for ampicillin, chloramphenicol, co-trimoxazole, and azithromycin. Minimum Inhibitory Concentration (MIC) determination by E-test for ciprofloxacin and ceftriaxone were performed. Results: Out of the 80 Salmonella isolates, 64 (80%) were S. typhi, and 16 (20%) were S. paratyphi A. Susceptibility to ampicillin, co-trimoxazole, and chloramphenicol was 97.5%. Only two (2.5%) were MDR strain. Regarding ciprofloxacin and nalidixic acid, 78 (97.5%) were resistant. All the isolates were sensitive to ceftriaxone (100%). Six out of 80 (7.5%) strains of S. typhi showed resistance to azithromycin. Conclusion: Re-emergence of susceptibility to first-line drugs suggests the possibility of using these drugs again in treatment. MIC for ciprofloxacin and ceftriaxone should be done routinely. Nalidixic acid resistance cannot be considered as a reliable surrogate marker. The emergence of resistance for azithromycin is a cause of concern.