关键词: 血培养, 病原菌鉴定, 基质辅助激光解吸电离飞行时间质谱, 短时培养法

Abstract:

Objective To analyze the clinical roles of rapid bacterial identification and drug susceptibility test of blood culture-positive samples by centrifuge enrichment method and 5 h culture method combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry（MALDI-TOF-MS）. Methods Totally，211 blood culture-positive samples at the First Affiliated Hospital of Ningbo University from October 2021 to October 2022 were collected. The pretreatment was performed by centrifuge enrichment method and 5 h culture method（rapid method）and 12 h culture method（standard method），respectively. MALDI-TOF-MS was used for rapid isolate identification of blood culture-positive samples treated by the 3 methods. The drug susceptibility test of 156 blood culture-positive samples from aerobic bottle was carried out by automatic microbiological identification drug susceptibility instrument. According to the identification results of conventional culture（18-24 h）+MS，the identification accuracy of 2 rapid methods of 5 h culture method+MS and centrifuge enrichment method+MS were compared. According to the identification results of 24 h，the consistency of the results of drug susceptibility test between standard method after 5 h culture method，centrifuge enrichment was evaluated. Results The identification accuracy of Enterococcus faecalis was the highest，and the identification accuracies were 100.00% and 87.50%，respectively. The identification accuracy of Streptococcus was low（33.33%）after 5 h culture method+MS. The drug susceptibility test results of the 2 methods for Enterobacteriaceae and non-fermentative bacteria were more than 73.00% and 85.00%，respectively，compared with the results of standard method. The results of drug susceptibility test for Staphylococcus and Enterococcus were consistent（100.00%）. The consistency of vancomycin sensitivity analysis was the lowest（70.73%）. Conclusions The 5 h culture method+MS and centrifuge enrichment method+MS can rapidly identify the isolate and drug resistance of pathogenic bacteria in blood culture-positive samples with high accuracy，which is suitable for clinical microbiology laboratories.

Key words: Blood culture, Pathogen identification, Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, Short-time culture method