Comparison of microarray and lysis filtration combined with MALDI-TOF MS methods for rapid diagnosis of gram-positive bacteria

Aim: Early diagnosis of sepsis is crucial for patients’ prognosis. The primary objective of this study is to compare three methods for identifying bacteria in blood cultures: MALDI-TOF MS post-culture, MALDI-TOF MS after lysis filtration (LFM), and the Verigene System BC-GP microarray. Furthermore, the study evaluates the resistance profiles using the microarray method. Materials and Methods: A total of 40 blood culture bottles positive for Gram-positive bacteria were collected from adult patients in the intensive care unit (ICU) of a university hospital. After detecting positive signals, we applied three identification methods: MALDI-TOF MS from subcultures, MALDI-TOF MS after lysis filtration directly from the liquid sample, and the Verigene System BC-GP microarray (Nanosphere Inc. Northbrook, USA) test. Results: The consistency of LFM identification and the microarray method compared to post-culture MALDI-TOF MS was 75% (30/40) and 90% (36/40), respectively. The agreement between LFM and the microarray method was 83.3% (30/36). All three methods were consistent in 67.5% (27/40) of the bottles. Conclusion: The study indicates that both lysis filtration and microarray methods are effective for rapid diagnosis in sepsis patients. Each method has its own advantages and limitations. Lysis filtration combined with MALDI-TOF MS offers a cost-efficient, fast, and broad-database approach, providing results in approximately 9-10 hours instead of the conventional 48-72 hours when combined with automatic susceptibility testing.