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|Year : 2009 | Volume
| Issue : 3 | Page : 276-
Ciprofloxacin breakpoints in enteric fever: Time to revise our susceptibility criteria
C Rodrigues, NJ Kumar, J Lalwani, A Mehta
Department of Microbiology, P. D. Hinduja National Hospital & MRC, Veer Savarkar Marg, Mahim, Mumbai - 400 016, Mumbai, India
Department of Microbiology, P. D. Hinduja National Hospital & MRC, Veer Savarkar Marg, Mahim, Mumbai - 400 016, Mumbai
|How to cite this article:|
Rodrigues C, Kumar N J, Lalwani J, Mehta A. Ciprofloxacin breakpoints in enteric fever: Time to revise our susceptibility criteria.Indian J Med Microbiol 2009;27:276-276
|How to cite this URL:|
Rodrigues C, Kumar N J, Lalwani J, Mehta A. Ciprofloxacin breakpoints in enteric fever: Time to revise our susceptibility criteria. Indian J Med Microbiol [serial online] 2009 [cited 2020 Feb 28 ];27:276-276
Available from: http://www.ijmm.org/text.asp?2009/27/3/276/53218
The Microbiology Section of P.D. Hinduja National Hospital & MRC conducted a study on 103 Salmonella enterica Serotype Typhi, between February 2005 to December 2005.
During this period, 96 Nalidixic Acid Resistant Salmonella Typhi (NARST) were isolated from this lot, The percentage of NARST isolated at the institute was 93.2%.
Agar dilution, as recommended by CLSI guidelines, was used in MIC determination. Medical records and clinical outcome of only 20 admitted patients could be accessed as since most patients are referred to our laboratory from across the city for only blood culture and medical records for these out patient referrals are not available. In seven patients, clinical failure with fluoroquinolones, given prior to admission, was recorded. Blood culture was positive in all of these seven, revealing microbiological failure. As part of the institution antibiotic policy, suspected patients of enteric fever, failing treatment on fluoroquinolones and warranting admission are empirically treated with ceftriaxone.
The Pharmacokinetic/Pharmacodynamic (PK/PD) measure, that is most predictive of efficacy, is indeed the free drug area under the concentration time curve from zero to 24 hours to the MIC ratio, with a ratio of 105 corresponding to 90% maximal activity. Simulation results suggest ciprofloxacin susceptible breakpoints of 0.12 pg/ml.  The AUC (mg/L.h), at a steady state (calculated as equivalent to AUC for single dose multiplexed by number of daily doses) for 750 mg, BID is 35.2.  In this series, of the 12 patients with MIC less than or equal to 0.25 μg/μl, only one patient had an MIC of 0.25 μg/μl and he was continued on therapy with ceftriaxone for 14 days.
This study emphasizes to the urgent need for clinical efficacy studies, of PK/PD breakpoints for ciprofloxacin, for S. enterica .
We thank Dr Gupta and Dr. Randhawa for their insightful and useful comments.
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