Antibiotic sensitivity pattern of Salmonella enterica serovar Typhi with special reference to nalidixic acid Swarooparani N.B.1, Wadekar Mita D.2,* 1Associate Professor, Subbaiah Institute of Medical Sciences, Shimoga, Karnataka 2Assistant Professor, Dept. of Microbiology, Chamarajanagar Institute of Medical Sciences, Chamarajanagar, Karnataka, India *Corresponding Author: E-mail: drmdw20@gmail.com
Online published on 24 September, 2018. Abstract Introduction Recently, Salmonella Typhi resistance to many of the commonly used antibiotics like chloramphenicol, amoxicillin and cotrimoxazole, has posed a challenge to treat enteric fever. Minimum inhibitory concentration (MIC) of ciprofloxacin is increasing which is responsible for both treatment failure and causing serious complications. Resistance to nalidixic acid can be used as an indirect indicator to detect increased ciprofloxacin MIC. Hence, study was conducted to know the antibiotic sensitivity pattern of Salmonella enterica serovar Typhi with special reference to nalidixic acid resistance. Materials and Methods A retrospective study of S. Typhi isolates was conducted. 106 blood samples from patients of all age group who were clinically suspected of enteric fever were included. Blood culture was done and S. Typhi isolates were identified and tested for susceptibility to ampicillin, chloramphenicol, cotrimoxazole, ciprofloxacin, ceftriaxone and nalidixic acid by disc diffusion method. Result 22(20.8%) S. Typhi isolates were isolated from 106 blood samples. Chloramphenicol showed 100% sensitivity. Susceptibility to ampicillin (81.8%), cotrimoxazole (81.8%) and ceftriaxone (90.9%) was high and to ciprofloxacin (72.7%) and nalidixic acid (45.5%) was low. Conclusion Ampicillin, chloramphenicol, cotrimoxazole and ceftriaxone showed maximum sensitivity and hence can be used for effective treatment. Nalidixic acid resistance was very high and all these resistant isolates showed decreased sensitivity to ciprofloxacin. Hence nalidixic acid sensitivity can be used for the detection of decreased susceptibility to ciprofloxacin. Top Keywords Salmonella Typhi, Ciprofloxacin, Resistance, Nalidixic acid. Top |