title: Revised Ciprofloxacin Breakpoints for Salmonella: Is it Time to Write an Obituary?
abstract: OBJECTIVE
  To determine the minimum inhibitory concentration of ciprofloxacin among 50 blood stream isolates of Salmonella enterica.
  
  
  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.
  
  
  CONCLUSIONS
  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!"
authors.affiliation: MSc, Department of Microbiology, Amrita Institute of Medical Sciences , Ponekara, Kochi-682041, Kerala India .
authors.forename: Revathy
authors.initials: R
authors.lastname: Girish
authors.affiliation: Clinical Associate Professor, Department of Microbiology, Amrita Institute of Medical Sciences , Ponekara, Kochi-682041, Kerala India .
authors.forename: Anil
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Clinical Assistant Professor, Department of Microbiology, Amrita Institute of Medical Sciences , Ponekara, Kochi-682041, Kerala, India .
authors.forename: Sadia
authors.initials: S
authors.lastname: Khan
authors.affiliation: Clinical Professor, Department of Microbiology, Amrita Institute of Medical Sciences , Ponekara, Kochi-682041, Kerala India .
authors.forename: Kavitha R
authors.initials: KR
authors.lastname: Dinesh
authors.affiliation: Professor & Head, Department of Microbiology, Amrita Institute of Medical Sciences , Ponekara, Kochi-682041, Kerala India .
authors.forename: Shamsul
authors.initials: S
authors.lastname: Karim
keywords: Breakpoints; Ciprofloxacin; Resistance; Salmonella paratyphi A; Salmonella typhi