Authors’ response

Sir,

We appreciate the authors1 for their keen interest in our work. We used CLSI Guidelines 2007 for interpreting the results of antibacterial drug sensitivity testing2.

The Table in the article2 shows the results of disk diffusion test as well as estimation of MIC using E-test. The categorization of the isolates as ‘Sensitive’, ‘Resistant’ and ‘Intermediate resistant’ was based purely on the results of disk diffusion test. We had estimated the MICs of only the fluoroquinolones and this had been mentioned in the article. Therefore, it was obvious that the categorization of the isolates’ drug sensitivity status was based on the results of disk diffusion test.

Khan and Anil Kumar1 point out that as per CLSI 2012, strains with MIC < 0.06 μg/ml are considered susceptible to ciprofloxacin. We thank them for adding this information. This change in the cut-off, obviously, would result in all our five isolates of S. enterica serovar Typhi being categorized as not susceptible to ciprofloxacin. Further, nowhere in the article did we mention that we used MICs to categorize the isolates’ drug sensitivity status. However, we agree that the use of the term ‘intermediate level resistance ‘ in the statement in the article (page 100, paragraph 3, lines 9-11) ‘…the remaining above the level (0.125 μg/ml) that is considered to confer intermediate level resistance…’ could be misleading and it should have been mentioned as ‘reduced susceptibility’.