Publication Type:

Journal Article


Journal of Clinical and Diagnostic Research, Volume 7, Number 11, p.2467-2469 (2013)



ampicillin, antibiotic sensitivity, article, azithromycin, bacterial strain, bacterium identification, bacterium isolate, bloodstream infection, chloramphenicol, ciprofloxacin, colony forming unit, controlled study, death, disk diffusion, human, minimum inhibitory concentration, nalidixic acid, nonhuman, practice guideline, Salmonella enterica, Salmonella paratyphi, Salmonella typhi, strain difference, typhoid fever


Objectives: To determine the minimum inhibitory concentration of ciprofloxacin among 50 blood stream isolates of Salmonella enterica. Material and Methods: A total of 50 consecutive isolates of Salmonella enterica were tested for susceptibility to antimicrobials using the Kirby Bauer disk diffusion method. Minimum inhibitory concentrations were determined using Hi-Comb strips. All results were interpreted according to the CLSI guidelines. Results: Of the 50 isolates 70%were Salmonella Typhi, 4% Salmonella paratyphi A, 2% Salmonella paratyphi B and the remaining 10% were identified only as Salmonella species. Using the CLSI 2011 breakpoints for disc diffusion, 86% (43/50) were resistant to nalidixic acid(NA), 22% (11/50) to ciprofloxacin, 12% to azithromycin, 6% to cotrimoxazole, 4% to ampicillin and 1% to chloramphenicol. The MIC50 and MIC90 of ciprofloxacin for S.Typhi were 0.181 μg/mL and 5.06 μg/mL respectively. While the same for S. paratyphi A was 0.212μg/mL and 0.228μg/mL respectively. None of the isolates were multi drug resistant and all were susceptible to ceftriaxone. Using the CLSI 2012 revised ciprofloxacin breakpoints for disc diffusion (>31mm) & MIC (<0.06 μg/mL), 90% (45/50) of these isolates were found to be resistant. Conclusion: MIC's of ciprofloxacin should be reported for all salmonella isolates and should be used to guide treatment. Blindly following western guidelines for a disease which is highly endemic in the subcontinent will spell the death knell of a cheap and effective drug in our armamentarium. Therefore it will be too premature to declare that "the concept of using ciprofloxacin in typhoid fever is dead!".


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Cite this Research Publication

R. Girish, V. Kumar, A., S. Khan, Dinesh, K. R., and Karim, S., “Revised ciprofloxacin breakpoints for Salmonella: Is it time to write an obituary?”, Journal of Clinical and Diagnostic Research, vol. 7, pp. 2467-2469, 2013.