Revised Ciprofloxacin Breakpoints
for Salmonella: Is it Time to Write
an Obituary?
Published: November 1, 2013 | DOI: https://doi.org/10.7860/JCDR/2013/.3581
Revathy Girish, Anil Kumar, Sadia Khan, Kavitha R. Dinesh, Shamsul Karim
1. MSc, Department of Microbiology, Amrita Institute of Medical Sciences, Ponekara, Kochi-682041, Kerala India.
2. Clinical Associate Professor Department of Microbiology, Amrita Institute of Medical Sciences, Ponekara, Kochi-682041, Kerala India.
3. Clinical Assistant Professor Department of Microbiology, Amrita Institute of Medical Sciences, Ponekara, Kochi-682041, Kerala, India.
4. Clinical Professor, Department of Microbiology, Amrita Institute of Medical Sciences, Ponekara, Kochi-682041, Kerala India.
5. Professor & Head, Department of Microbiology, Amrita Institute of Medical Sciences, Ponekara, Kochi-682041, Kerala India.
Correspondence Address :
Dr. V. Anil Kumar,
Amrita Institute of Medical Sciences, Ponekkara, Kochi, Kerala-682041, India.
Office:+91484 2801234 (Extn: 8015), Fax: +91484 2802020,
Mobile: +919037401413
E-mail: vanilkumar@aims.amrita.edu
Abstract
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!”
Keywords
Salmonella typhi, Salmonella paratyphi A, Ciprofloxacin, Resistance, Breakpoints