Concordance between HB&L system and conventional culture method for bacterial antibiotic susceptibilities from positive blood samples at Hospital for Tropical Diseases from 03/2020 to 04/2021

Presently, shortening the time-to-result of antimicrobial susceptibility test (AST) is of the utmost importance for sepsis management in an effort to reduce mortality and antibiotic resistance rate. HB&L ((Human Biological Liquid Culture), a product of the Alifax company (Italy), can detect replicating microorganisms and their antibiotic resistance in a few hours with high sensitivity and specificity by using light scattering technique. This study aims to evaluate the correlation between rapid antibiogram using the HB&L system and the routine methods on positive blood cultures at the Hospital for Tropical Diseases in Ho Chi Minh City from March 2020 to April 2021. Gram-positive bacteria blood samples were tested against Cefoxitin, Vancomycin while Gram-negative bacteria samples were trialed with Ceftriaxone, Levofloxacin, Piperacillin-Tazobactam and Meropenem. The concordance of the two methods was defined by the categorical agreement (CA), very major errors (VME), major errors (ME) and minor errors (mE) in Cumitech 31A. Of the 81 blood culture samples containing Gram-negative bacteria, the CA of Ceftriaxone, Meropenem, Levofloxacin and Piperacillin-Tazobactam were 90%, 100%, 67% and 88%. The maximum VME was 22% for Levofloxacin. On the other hand, of the 32 Gram-positive samples, CA and VME of Cefoxitin were 53% and 65% respectively while CA of Vancomycin was 100%. The median time to receive rapid AST results of the HB&L system is 4.43 hours faster than the standard that.