Agreement between AST from minute colony (8-10h growth) and mature colony (16-18h/overnight incubation)

Sepsis is a medical emergency where a successful patient outcome depends on early and appropriate antibiotic treatment. This study was conducted to evaluate agreement between antimicrobial susceptibility testing (AST) from minute colonies that can reduce the AST-TAT by as much as 8-10h as compared to the CLSI recommended protocol of performing AST from an overnight (16-18h) growth of mature colony. In the present study, mDD results from minute colony (8-10h growth) were compared to the rDD results mature colony (16-18h/overnight incubation) CA and various types of errors were evaluated. 237 pathogens and 1597 organism-antibiotic combinations were evaluated, there was a CA of 93.30% which was extremely satisfactory and categorical disagreement was found only in 4.56% of organism-antibiotic combinations, which were mainly mE (4.56%) with nil VME (0%) and ME (0%). We have found that minute colony (8-10h) AST is in agreement with reference mature colony (16-18h) AST, shortening TAT by (8-10h) earlier than the conventional reference method which is very helpful in treatment of sepsis patients.