Antimicrobial Susceptibility Pattern of Salmonella enterica Species in Blood Culture Isolates

Introduction: Enteric fever continues to be a major health problem in under developed countries including south Asian nations. In this study, we evaluate the prevalence and susceptibility pattern of Salmonella enteric (Serotype typhi, Paratyphi A and Paratyphi B). Methods: Blood samples were obtained from 3210 patients, suspected with enteric fever. The sample was processed on BACTEC 9050 and isolates obtained from subculture were serotyped and antibiotic susceptibility testing was carried out using disk diffusion (Kirby–Bauer). Result: Out of 3120 samples 370 isolates of S. enterica were isolated. The prevalence of Salmonella enterica was 11.8 % where 78.4% of these isolates were S. enteric serotype Typhi, 20.8% were S. enteric serotype Paratyphi A and0.8% were S. enteric serotype Paratyphi B. The isolates demonstrated poor susceptibility to oral antibiotics including Nalidixic acid, Ciprofloxacin, Ofloxacin, Azithromycin ,Amoxycillin, Tetracycline, Ceftriaxoneand Trimethoprim–sulfamethoxazole whereas all of the isolates of S. enterica demonstrated 100% susceptibility to Chloramphenicol. Conclusion: There was grater prevalence of Salmonella enterica serotype typhi isolates resistant to fluoroquinolones (Nalidixic acid, Ofloxacin and Ciprofloxacin). However Chloramphenicol was sensitive to all isolates. This study suggests Chloramphenicol as a drug of choice for enteric fever and further monitoring of efficacy of older and newer antibiotics are desirable.