Antimicrobial Susceptibility Patterns of Salmonella enterica Serotype Typhi in Eastern Nepal

The aim of the present study was to evaluate antimicrobial susceptibility patterns with special reference to multidrug resistance, susceptibility to ciprofloxacin, and bacteriophage typing of Salmonella enterica serotype Typhi isolated from blood sent for culture in a tertiary-care teaching hospital in eastern Nepal during January 2000–December 2004. In total, 132 strains of S. enterica Typhi, isolated from 2,568 blood culture samples collected from cases of suspected enteric fever, were tested for susceptibility to commonly-used antimicrobials by the disc-diffusion method. There were 35 multidrug-resistant strains. None of the isolates were resistant to ciprofloxacin.Of 52 isolates tested for minimum inhibitory concentration (MIC) of ciprofloxacin, 36 (69.23%) showed reduced susceptibility (MIC ≥0.25 mg/L). Of 112 strains tested for nalidixicacid susceptibility,86(76%) were resistant. Strains with reduced susceptibility to ciprofloxacin and resistance to nalidixic acid could be correlated. The commonest phage type was E1. Nalidixic acid susceptibility could be a useful screening test for the detection of decreased susceptibility of S. Typhi to ciprofloxacin, a drug which is commonly used even for minor ailments in this area.

Keywords
Salmonella Typhi; Typhoid; Drug resistance, Microbial; Microbial sensitivity tests; Ciprofloxacin; Minimum inhibitory concentrations; Nepal