脐血采集和分离过程中病原微生物污染概率的研究

The Probability of Microbiological Contamination during the Collection and Processing of Umbilical Cord Blood

为探讨脐血采集、分离过程中病原微生物污染的概率及不同检测方法的有效性,采用BACTEC 9050细菌培养系统和改良马丁/硫乙醇酸盐(22℃)及硫乙醇酸盐(35℃)培养法对60份脐血同时进行采集后及分离后细菌和真菌的培养;对206份脐血血清标本采用ELISA法检测HBsAg,Anti-HBC,Anti-HCV,Anti-HCMV-IgM,HTLV-1,HTLV-2,HIV-1及HIV-2;用分子生物学方法检测HBV DNA和HCV RNA;用红细胞凝集法检测TPHA。研究结果显示:采用BACTEC 9050细菌培养系统,采集后脐血中细菌污染率为3.33％,真菌污染率为0％;细胞分离后细菌和真菌污染率分别增高到6.67％和1.67％;在该系统中,厌氧菌的阳性检出率远高于改马丁/硫乙醇酸盐(22℃和35℃)。脐血血清病原菌检测结果表明:采用ELISA方法,HBsAg阳性率2.4％,Anti-HBC单项阳性率29.4％,Anti-HCMV-IgM阳性率1.89％ ;采用分子生物学方法,HBV DNA阳性率5.8％,HBsAg阴性而HBCAb单项阳性标本中HBV DNA阳性率6.7％,HCV RNA阳性率2.4％。结论:采集及分离后脉血细胞中病原微生物阳性率甚高;目前沿用的改良马丁/硫乙醇酸盐(22℃和35℃)培养系统,会导致脐血中厌氧菌漏检,有必要更新该培养方法,如采用先进的BACTEC 9050培养体系。分子生物学方法可弥补ELISA等常规脐血传染病检测方法的缺陷。

To study the pathogens incidences in cord blood and the efficiency of different detective methods,60 samples were drawed and reserved from collected and processed cord blood,respectively.The BACTEC 9050 system,improved Martin/thioglycollate broth (22C ) and thioglycollate broth(351C ) were employed to detected bacteria (including fungus) at the same time.Two hundred and six cord blood serum samples were used to detect the HBV DNA and HCV RNA by molecular biology technique,HBsAg,Anti-HBC,Anti-HCV,Anti-HCMV-IgM,HTLV-1,HTLV-2,HIV-1 and HIV-2 by ELISA and RBC agglutination test were used to detect the TPHA.Results showed that using BACTEC 9050 system,the incidence of bacteria and fungus was 3.33% and 0% respectively in collected cord blood; in processed cord blood,the rates increased to 6.67% and 1.67%,respectively.The sensitivity of BACTEC 9050 was higher than that of Martin/ thioglycollate broth(22t: /35t) culture.In 206 serum samples,the positive rate of HBV DNA was 5.8 %,HCV RNA was2.4%,HBsAg was 2.4%,HCMV-IgM was 1.89%,HCV was 2.4% and Anti-HBC was 29.4% .In those samples that anti-HBC were positive,the positive rate of HBV DNA was 6.7%.It was concluded that the incidences of microbiological contamination in cord blood were high.The routine culture system would lead to false negative results of obligate anaerobes.It was necessary to replace the current culture system with improved system,such as BACTEC 9050 system.The molecular biology technique would make up for the default of ELISA.