利用MALDI-TOF MS快速鉴定经固体培养基短时培养的阳性血培养物中的病原菌

Rapid identification of microorganisms from positive blood cultures by maldi-tof mass spectrometry following short-term incubation on solid medium

目的探讨利用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)快速鉴定经固体培养基短时培养的阳性血培养物中的病原菌的可行性,为临床早期诊断血流感染并提供合理的用药依据。方法血培养瓶呈阳性结果以后按照日常处理流程转种于血平板上,孵育2、4、6、8h后,挑取菌膜于靶标板上,用MALDI-TOF MS进行病原菌鉴定。同时,所有标本经过16～24h的隔夜培养后,用MALDI-TOF MS、VITEK?Compact、各种生化反应以及凝集反应进行确认。结果该研究共有来自102例患者的171份单一菌感染的血培养阳性瓶用于试验,包括76份(44.4%)革兰阳性菌和95份(55.6%)革兰阴性菌。与最终鉴定结果比较,在转种培养2、4、6、8h时用MALDI-TOF MS进行鉴定的成功鉴定率分别为106份(62.0%)、150份(87.7%)、161份(94.2%)、165份(96.5%);其中,革兰阳性菌的鉴定率分别为26份(34.2%)、56份(73.7%)、66份(86.9%)、70份(92.3%),革兰阴性菌的鉴定率分别为80份(84.2%)、94份(98.9%)、95份(100.0%)、95份(100.0%)。结论该研究表明,利用MALDI-TOF MS快速鉴定经固体培养基短时培养的阳性血培养物中的病原菌是一个早期可靠的方法。

Objective To explore the feasibility of rapid identification of pathogenic bacteria in positive blood cultures cultured on solid medium by matrix assisted laser desorption/ionization time of flight mass spectrometry （MALDI TOF MS） ,and to provide a rational basis for clinical early diagnosis of bloodstream in fection. Methods After the blood culture flask showed the positive results,they were transferred to the blood plate according to the routine treatment process, the bacterial membrane was selected on the target plate after incubation for 2,4,6 and 8 hours,and the pathogens were identified by MALDI TOF MS. At the same time,all specimens were cultured overnight for 16 to 24 hours and confirmed by MALDI TOF MS,VITEK Compact, various biochemical reactions and agglutination reactions. Results A total of 171 blood culture positive flasks from 102 patients were tested, including 76 （44.4%） gram positive bacteria and 95 （55. 6%） gram negative bacteria. Compared with the final identification results,the successful identification rates of MALDI TOF MS were 106 （62.0%） ,150 （87.7%） ,161 （94.2%） and 165 （96.5%） at 2,4,6,and 8 h after transfection culture, respectively. Among them, the identification rates of Gram positive bacteria were 26 （34.2%） ,56 （73.7%） ,66 （86.9%） and 165 （96.5%） respectively. 70 （92.3%） were identified,and the identification rates of Gram neg ative bacteria were 80 （84.2%）,94 （98.9%）,95 （100%） and95 （100%） respectively. Conclusion This study showed that the rapid identification of pathogenic bacteria in short term positive blood culture by MALDITOF MS was an early and reliable method.