Rapid Bacterial Identification and Drug Sensitivity Test Methods for Pathogens in Positive Blood Cultures

The turnover time of positive blood culture using traditional methods takes too long. This study aimed to evaluate rapid direct identification and drug sensitivity test methods for pathogens in positive blood cultures.

A total of 403 blood culture bottles were used to compare the rapid identification methods and drug sensitivity tests for pathogens causing bloodstream infections. Bacteria were enriched using separator gel tubes and were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. In addition, bacteria were also identified using an established traditional method for comparison. The sensitivity of gram-negative bacilli against antibiotics was tested using Rapid Bacterial Test Strips or the VITEK 2 Compact system.

The accuracy was 81.8% in 403 bacteria, of which 71% (132/186) and 96.3% (209/217) were gram-positive and gram-negative bacteria, respectively. The gram-positive bacteria were primarily Staphylococcus aureus and coagulase-negative Staphylococcus. The gram-negative bacteria were primarily Escherichia coli and Klebsiella pneumonia. Compared with routine drug sensitivity testing methods, the coincidence rate of direct drug sensitivity testing for classifying the bacteria was 98.6% (1,325/1,344). The average rapid bacterial identification time was 1.5 hours, and the direct drug sensitivity test took - 8.5 hours.

The present study showed that direct identification and rapid drug sensitivity testing can be performed on the same day and can be completed 1 or 2 days ahead of routine methods, thereby assisting in providing earlier drug options for anti-infective therapy.