MALDI-TOF MS快速鉴定联合直接药敏试验在尿路感染诊断中的应用评估

An Evaluation of MALDI- TOF MS Rapid Identification Combined DirectAntimicrobial Susceptibility Test for the Diagnosis of Urinary Tract Infection

目的评估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)快速鉴定联合直接药敏试验在尿路感染(urinary tract infection,UTI)诊断中的临床应用价值。方法收集2022年5月至12月首都医科大学附属世纪坛医院清洁中段尿培养样本共2610份。全部通过MUS9600全自动尿液分析系统筛选后,经差速离心浓缩纯化后使用MALDI-TOF MS直接鉴定,使用Vitek 2 Compact全自动微生物鉴定和药敏系统,K-B法及ATB FUNGUS3进行直接药敏试验,并根据美国临床实验室标准化研究所(CLSI)发布的药敏试验标准进行结果判读。将其结果与清洁中段尿培养鉴定药敏结果进行比较。结果2610例清洁中段尿培养样本中经常规鉴定后共有阳性483例(483/2610,18.51%),阴性或疑似污染2127例(2127/2610,81.49%)。与MUS9600计数结果相比,阳性样本符合率为97.92%(472/483):其中杆菌97.90%(280/286),球菌98.48%(130/132),真菌92.31%(60/65)。阴性及污染样符合率为98.92%(2104/2127)。在这483个样本中,质谱快速鉴定符合率为90.48%(437/483),其中,革兰氏阴性菌92.86%(260/280),革兰氏阳性菌89.13%(123/138),真菌83.10%(54/65)。对部分阳性样本进行了直接药敏试验。革兰阴性杆菌数据显示,直接药敏试验与传统药敏试验的符合率为94.42%(5552/5880),微小错误率、严重错误率和非常严重错误率分别为4.42%(260/5880)、0.95%(56/5880)和0.20%(12/5880)。革兰氏阳性球菌数据显示,直接药敏试验与传常规药敏试验的符合率为91.91%(1340/1458),微小错误率、严重错误率和非常严重错误率分别为5.69%(83/1458)、1.65%(24/1458)和0.75%(11/1458)。假丝酵母菌药敏数据显示,直接药敏试验与传统药敏试验的符合率为77.69%(101/130),微小错误率、严重错误率和非常严重错误率分别为16.15%(21/130)、4.62%(6/130)和1.54%(1/130)。结论我们的发现表明,以MUS9600筛选,MALDI-TOF MS直接鉴定和Vitek 2 Compact、K-B法及ATB FUNGUS3直接药敏试验的组合为清洁中段尿培养提供了较直接、快速和可靠的鉴定和药敏结果,在尿路感染的早期诊断和合理治疗中具有显著的临床价值。

Objective To evaluate the clinical value of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS)rapid identification combined direct antimicrobial susceptibility test for the diagnosis of urinary tract infection(UTI).Methods A total of 2610 midstream urine samples were processed during May to December,2022 from outpatients and inpatients settings.All samples were analyzed by Mindray MUS9600 automatic urine analyzer.The samples with positive cultures were purified and concentrated by differential centrifugation.MALDI-TOF MS was then used for a rapid identification.VITEK 2 Compact,ATB FUNGUS3 and Disk diffusion were selected to conduct direct antimicrobial susceptibility test according to the result of rapid identification.The midstream urine culture and antimicrobial susceptibility test were used as the reference standard.The antimicrobial susceptibility test was performed according to the standards of the American Society for Clinical and Laboratory Standardization(CLSI).Results In total,483 out of 2610 patients were found to be positive(483/2610,18.51%),while 2,127 were contaminated or negative(2127/2610,81.49%).Compared with the midstream urine culture result,the coincidence rate of MUS9600 bacterial count in positive urine samples was 97.72%(472/483):the bacillus was 97.90%(280/286),the coccus was 98.48%(130/132)and the fungus was 92.31%(60/65).For the contaminated or negative urine samples,the coincidence rate was 98.92%(2104/2127).Compared with the midstream urine culture and antimicrobial susceptibility test,the rapid identification by MALDI-TOF MS showed that the total coincidence rate was 90.48%(437/483):Gram-negative bacteria was 92.86%(260/280),while Gram-positive bacteria was 89.13%(123/138)and fungus was 83.10%(54/65).Direct antimicrobial susceptibility test showed that the coincidence rate of Gram-negative bacillus was 94.42%(5552/5880),with minor,major,and very major error rates of 4.42%(260/5880),0.95%(56/5880),and 0.20%(12/5880),respectively.The coincidence rate of Gram-positive coccus was 91.91%(1340/1458),with minor,major,and very major error rates of 5.69%(83/1458),1.65%(24/1458),and 0.75%(11/1458),respectively.And the coincidence rate of Candida was 77.69%(101/130),with minor,major,and very major error rates of 16.15%(21/130),4.62%(6/130),and 1.54%(1/130),respectively.Conclusion Overall,our findings show that the combination of MALDI-TOF MS rapid identification and direct antimicrobial susceptibility test can provide a direct,rapid,and reliable identification and AST result for the midstream urine culture,which has a remarkable clinical value for the early diagnosis and reasonable treatment of UTI.