Minimum inhibitory concentration of Ceftazidime-Avibactam against Clinical isolates of XDR Salmonella enterica Serovar Typhi

Background: Typhoid fever is a major healthcare problem in low and middle-income countries. The emergence of extensively drug-resistant (XDR) typhoid has further narrowed down the way to already limited therapeutic options. WHO has listed S.Typhi amongst the priority pathogens against which new treatment options should be discovered.Objective: To determine In-vitro activity of Ceftazidime-avibactam against clinical isolates of XDR S.Typhi.Study design: This is a cross-sectional studyPlace and duration of the study: The Department of Microbiology, University of health sciences, Lahore from January to June 2021.Methodology: Antimicrobial susceptibility was performed initially by Kirby Bauer disc diffusion method for 150 of XDR Salmonella enterica Serovar Typhi and MICs of all the recommended antibiotics was determined by VITEK 2 (bioMérieux) fully automated system using Clinical Laboratory Standard Institute (CLSI) 2021 guidelines. MICs by the E-test method were determined for Ceftazidime-avibactam and Azithromycin only. All tests were done in duplicate.Results: All 150 (100%) isolates were sensitive to Ceftazidime-avibactam by disc diffusion and E-test methods. Out of 150 isolates 8(5.3%) were having high MICs against Azithromycin.Conclusions: Ceftazidime-avibactam can be used wisely to treat ESBL producing XDR typhoid fever cases especially in countries like Pakistan where Typhoid fever is endemic and majority of isolates are extensively drug resistant.