Susceptibility to patterns of ciprofloxacin among nalidixic acid-resistant Salmonella isolates collected in Banepa, Nepal from enteric fever patients

Abstract

The present study determined the susceptibility to ciprofloxacin of nalidixic acid resistant Salmonella (NARS) isolated from enteric fever patients at Scheer Memorial Hospital, Banepa, Nepal, from June 2012 to December 2012. The antimicrobial sensitivity to nalidixic acid and ciprofloxacin was determined using modified Kirby-Bauer disc diffusion and broth dilution method according to the guidelines of the Clinical and Laboratory Standard Institute. Salmonella was isolated from 34 out of 992 (3.43%) blood cultures collected during the study period, and 10 (29.4%) isolates were identified as Salmonella enterica serotype Typhi, while 24 (70.6%) were identified as Salmonella enterica serotype Paratyphi. Out of the total isolates, 31 (91.2%) were nalidixic acid-resistant Salmonella (NARS). Among NARS, the minimum inhibitory concentration values for ciprofloxacin ranged from 0.25 to 2 mg/L and were constantly higher than those shown by the nalidixic acid-susceptible Salmonella. Therefore, in typhoid Salmonella nalidixic acid resistance may be the indicator of decreased susceptibility to ciprofloxacin.

Keywords

• Enteric fever
• Multi-drug resistant
• Nalidixic acid-resistant Salmonella
• Minimum inhibitory concentration
• Ciprofloxacin