MALDI-TOF MS技术对VIM型和SPM型金属酶铜绿假单胞菌的检测分析

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for detection of VIM-and SPM-type metallo-β-lactamase-producing Pseudomonas aeruginosa

目的了解基质辅助激光解吸电离飞行时间质谱(matrix-assisted laser desorption/ionization time-of-flight mass spectrometry,MALDI-TOF MS)在检测金属酶铜绿假单胞菌(metallo-β-lactamase Pseudomonas aeruginosa,MBL-PA)类型中的作用。方法收集2015—2018年重庆某三甲医院临床分离的258株碳青霉烯类耐药铜绿假单胞菌进行EDTA协同试验和耐药基因检测,通过建立VIM型和SPM型MBL-PA识别模型数据库,对MALDI-TOF MS检测MBL-PA类型的灵敏度、特异度、阳性预测值和阴性预测值进行分析。结果258株碳青霉烯类耐药铜绿假单胞菌中EDTA表型初筛试验阳性106株,经PCR耐药基因检测得到VIM型40株,SPM型35株。通过MALDI-TOF MS识别模型检测出23/25 VIM型菌株,灵敏度为92.0%,特异性为100.0%,阳性预测值为100.0%,阴性预测值为93.7%。对于SPM型菌株,检测出16/20,灵敏度为80.0%,特异性为100.0%,阳性预测值均为100.0%,阴性预测值为88.2%。结论MALDI-TOF MS在检测MBL-PA方面比常规PCR技术更有优势,通过构建识别模型可快速准确地鉴别VIM型和SPM型MBL-PA,具备非常广的应用前景。

Objective To evaluate the performance of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS)for detecting VIM-and SPM-type metallo-β-lactamase-producing Pseudomonas aeruginosa(MBL-PA).Methods A total of 258 clinical isolates of carbapenem-resistant P.aeruginosa collected from our hospital from 2015 to 2018 were analyzed using EDTA test and PCR-based drug resistance gene detection.A VIM-and SPM-type recognition model database was established to assess the sensitivity,specificity,positive predictive value and negative predictive value of MALDI-TOF MS for detecting different types of MBL-PA.Results EDTA test detected 106 positive strains from the 258 clinical isolates of carbapenem-resistant P.aeruginosa,and PCR-based drug resistance gene detection identified 40 VIM-type MBL-PA strains and 35 SPM-type MBL-PA strains.The MALDI-TOF MS recognition model detected 23 out of 25 VIM-type MBL-PA strains with a sensitivity of 92.0%,a specificity of 100.0%,a positive predictive value of 100.0%,and a negative predictive value of 93.7%,and identified 16 out of 20 SPM-type MBL-PA strains with a sensitivity of 80.0%,a specificity of 100.0%,a positive predictive value of 100.0%,and a negative predictive value of 88.2%.Conclusion MALDI-TOF MS has more advantages than conventional PCR in detecting the types of MBL-PA,and can quickly and accurately identify the VIM-and SPM-type MBL-PA after construction of a recognition model.