Bactericidal activities and post-antibiotic effects of ofloxacin and ceftriaxone against drug-resistant Salmonella enterica serovar Typhi

Abstract

Background: The clinical response to ceftriaxone in patients with typhoid fever is significantly slower than with ofloxacin, despite infection with Salmonella enterica serovar Typhi (S. Typhi) isolates with similar susceptibilities (MIC 0.03-0.12 mg/L). The response to ofloxacin is slower if the isolate has intermediate susceptibility (MIC 0.25-1.0 mg/L). Objectives: To determine the bactericidal activity and post-antibiotic effect (PAE) of ceftriaxone and ofloxacin against S. Typhi. Methods: The mean time to reach a 99.9% reduction in log10 count (bactericidal activity) and PAE of ceftriaxone and ofloxacin were determined for 18 clinical isolates of S. Typhi in time-kill experiments (MIC ra..