Prevalence of Shigella species and their antimicrobial resistance patterns in Eastern Nepal.

The study was conducted to determine the prevalence of Shigella species and their antimicrobial resistance patterns in eastern Nepal. Stool samples submitted to the diagnostic laboratory of B.P. Koirala Institute of Health Sciences, Nepal, during August 2000-July 2004, were cultured for Shigella species and were confirmed by biochemical and serological tests. Of 53 Shigella species isolated, Shigella dysenteriae type 1 was the most predominant isolate (73.7%), followed by S. flexneri (23%) and S. boydii (4%). The majority (79%) of Shigella species were isolated from children aged less than five years. An overall high resistance was observed for trimethoprim-sulphamethoxazole, ampicillin, nalidixic acid, mecillinam, and ciprofloxacin. There was a statistically significant (p < 0.001) increasing trend in the prevalence of ciprofloxacin resistance in S. dysenteriae type 1. The results suggest reconsideration of the empiric use of these antimicrobial agents for shigellosis. A further study is required to evaluate additional antimicrobial agents.