Comparision of Direct Antibiotic Susceptibility Testing with Standard Testing in Blood Culture

Abstract

To perform Direct Antibiotic Susceptibility Testing (DAST) on positive blood culture and compare with that of standard antibiotic susceptibility testing. Blood cultures performed at Department of Microbiology Kasturba Medical College and Microbiology diagnostic centre (KMC hospital Ambedkar circle), Mangalore. Blood cultures with monobacterial bacteraemia. Cross sectional comparative time bound study of 116 samples. Out of 116 positive blood culture samples. It was seen that over all error rate was 55.17% minor error/categorical error, 15.5% of major error and 0.8% of very major errors were detected. The inoculum size influences the result of DAST and standard AST. Therefore standardization of inoculum is crucial. To conclude DAST using disk diffusion from positive blood culture bottles help to start early antibiotic treatment for bacteraemia/septicaemia.

Keywords

• blood stream infection
• direct antibiotic susceptibility testing
• concordance