Objective To evaluate a method for determining pathogenic bacteria rapidly in midstream urine by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS)combined with short-term culturing. Methods A total of 1873 samples of midstream urine were collected. Each sample was divided equally into 2 parts. One was used for routine midstream urine culturing and identified by Vitek 2 Compact, the other was used for short-term culturing for 4 or 6 h after centrifugation,and then moss was collected and identified directly by MALDI-TOF MS. Identification by Vitek 2 Compact and quantitative culturing was considered as gold standard to evaluate the sensitivity and specificity of MALDI-TOF MS combined with short-term culturing for determining pathogenic bacteria in midstream urine. Results A total of 381 samples were determined with pathogenic bacteria in 1873 samples,and the positive rate was 20.3%. Among them,346 cases (90.8%) had single species,27 cases (7.1%) had 2 species,and 8 cases (2.1%)had≥3 species. In samples with single species,the determination rate in 4 h culturing group was 80.1% (277/346),and the determination rate in 6 h culturing group was 97.1% (336/346) by MALDI-TOF MS directly. The coincidence rate of MALDI-TOF MS combined with 6 h culturing compared with routine culturing was 100.0%,except Acinetobacter baumannii, Enterococcus faecium and Enterococcus faecalis(their coincidence rates were 81.4%,76.9% and 86.7%). Conclusions The midstream urine samples are cultured for 4-6 h after centrifugation,then identified by MALDI-TOF MS directly. This method could effectively shorten both culturing time and turn-around time.%目的 探讨基质辅助激光解析电离飞行时间质谱(MALDI-TOF MS)结合短期培养法快速检测中段尿样本中病原菌的价值.方法 收集1873例患者的中段尿样本,每份样本一分为二,一份用于中段尿常规培养结合Vitek 2 Compact微生物鉴定仪检测;另一份样本离心集菌后,短期培养4或6 h,采集菌膜直接用MALDI-TOF MS进行鉴定,并以中段尿定量培养结合Vitek 2 Compact微生物鉴定仪的检测结果为金标准,评估MALDI-TOF MS结合短期培养法对尿路感染病原菌鉴定的敏感性及特异性.结果 在1873例临床样本中常规培养方法检出病原菌381例,阳性检出率为20.3%.其中单一细菌生长的样本346例(90.8%),2种细菌生长的样本27例(7.1%),3种及3种以上细菌生长的样本8例(2.1%).在单一细菌生长的样本中,短期培养4 h后MALDI-TOF MS直接检测的检出率为80.1%(277/346),短期培养6 h后MALDI-TOF MS直接检测的检出率为97.1%(336/346).除鲍曼不动杆菌、屎肠球菌和粪肠球菌鉴定符合率稍低(81.4%、76.9%和86.7%)外,MALDI-TOF MS结合6 h短期培养法的鉴定符合率均为100.0%.结论 将中段尿样本离心集菌后短期培养4~6 h,采集菌膜直接用MALDI-TOF MS进行检测,可大大缩短培养时间,为临床提供快速的病原菌报告.
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