Objective:To investigate the effect of matrix-assisted laser desorption/ionizationtime-of-flight mass spectrometry(MALDI-TOF MS)combined with VITEK2 in the drug susceptibility test of pathogenic bacteria of bloodstream infection.Methods:During the period spanning January 1,2022,to December 31,2022,126 blood stream infection positive samples were obtained from the microbiology repository of the Second People's Hospital of Jingdezhen.These samples underwent microbial identification using both conventional methods and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry(MALDI-TOF MS).Subsequently,Antimicrobial Susceptibility Testing(AST)was carried out utilizing the VITEK2 system.A comparative analysis was then conducted to evaluate the concordance between bacterial strain identification outcomes and antimicrobial resistance patterns obtained from the two aforementioned identification methodologies.Results:The conventional identification methods achieved a perfect accuracy of 100%in discriminating Gram-negative and Gram-positive bacteria at both genus and species levels,with zero instances of inconclusive results or misidentifications.MALDI-TOF MS demonstrated an accuracy of 97.7%(85/87)at the genus level and 95.4%(83/87)at the species level for Gram-negative bacteria,with only two cases resulting in inconclusive outcomes(1 case enterobactercloacaesubsp.cloacae;1 case sphingomonas paucimobilis).Similarly,for Gram-positive bacteria,MALDI-TOF MS attained an accuracy of 97.4%(38/39)at both taxonomic levels,with only one inconclusive result(S.Coriolis urealyticum subsp).Conventional methods and VITEK2 in categorical agreement(CA)and essential agreement(EA)for gram-negative in AST reached 98.6%(1 086/1 101)and 99.5%(1 096/1 101)respectively;CA and EA for gram-positive in AST reached 98.6%(550/558)and 99.6%(556/558)respectively.MALDI-TOF MS+VITEK2(VITEK MS)in CA and EA for gram-negative in AST reached 98.3%(1 082/1 101)and 99.5%(1 095/1 101)respectively;CA and EA for gram-positive in AST reached 97.8%(546/558)and 99.5%(555/558)respectively.Refering to broth dilution method-derived drug sensitivity results,it revealed Major Interpretive Errors(MIE)in 10 AST samples and Minor Errors(ME)in 5 AST samples for Gram-negative bacteria.For Gram-positive bacteria,the conventional method yielded 8 instances of MIE and 2 instances of ME,whereas VITEK MS demonstrated 13 instances of MIE and 6 instances of ME.Additionally,in the drug susceptibility test of Gram-positive bacteria,9 instances of MIE and 3 instances of ME were observed.Conclusion:MALDI-TOF MS combined with VITEK2 can realize rapid and accurate diagnosis and provide AST report in clinical bloodstream infection pathogenic identification and drug susceptibility test.
关键词
基质辅助激光解吸/电离飞行时间质谱/血流感染/抗菌药物敏感性试验
Key words
Matrix-assisted laser desorption/ionizationtime-of-flight mass spectrometry/Blood stream infection/Anti-microbial susceptibility testing
维普
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