聚合酶链反应检测病原菌在儿童先天性心脏病术后呼吸机相关性肺炎中的应用价值

The value of polymerase chain reaction assay in ventilator.associated pneumonia in children undergoingcongenital heart disease operation

目的探讨聚合酶链反应（polymerasechainreaction，PCR）检测病原菌在儿童先天性心脏病术后呼吸机相关性肺炎（ventilator—associatedpneumonia，VAP）中的应用价值。方法我院胸外科重症监护室2016年11月至2017年7月收治的95例先天性心脏病术后发生VAP的患儿中，选取48例患儿行支气管肺泡灌洗（bronchoalveolarlavage，BAL）及导管内抽吸分泌物（endotrachealtubeattracts，ETA）法收集深部气道分泌物，获取病原学标本，并同时行传统气道分泌物定量培养法和PCR法检测病原菌。结果传统培养法培养72h后，检出19例标本病原菌呈阳性，共检出病原菌20株，2例标本为混合感染，病原菌检出阳性率为39．2％（19／48）。PCR法培养24h后检出31例标本病原菌呈阳性，共检出病原菌44株，9例标本为混合感染，病原菌检出阳性率为65．3％（31／48）。PCR法病原菌总体阳性率高，混合病原菌检出率高。采用ETA和BAL两种方法获取标本，用PCR法检测病原菌，各种病原菌的检出有高度一致性，48例标本中，45例病原菌检测结果一致，一致率高达94％（45／48）。结论PCR法可以快速敏感及准确地检测病原菌，临床中可通过非侵袭性操作ETA方法获取标本，应将PCR法和传统培养法结合作为儿童先天性心脏病术后VAP病原菌的检测方法。

Objective To explore the value of polymerase chain reaction（PCR） to detect pathogens in ventilator-associated pneumonia（VAP） in children undergoing congenital heart disease（CHD） operation. Methods Forty-eight children selected from 95 cases with VAP underwent CHD operation were admitted in the department of CICU in our hospital from November 2016 to July 2017. Sputum specimens were separately collected by the bronchoalveolar lavage （BAL） and endotracheal tube attracts （ETA） methods, and the patho- gens were detected by culture and PCR assay. Results Nineteen specimens were found to be positive after 72 h of culture. A total of 20 pathogens were detected and 2 samples were mixed infection （ more than one pathogen）, and the positive rate was 39.2% （ 19/48 ）. For PCR assay, 44 pathogens from 31 samples were detected for just 24 h,22 samples were single pathogen infection,9 samples were mixed pathogen infection, and the positive rate was 65.3% （31/48）. Compared with culture method, PCR assay could sharply increase the detection rate of every pathogen. Besides, the positive rate of the BAL or ETA for PCR assay was almost the same（45/48）. Conclusion PCR assay for detecting pathogens is rapid, accurate and effective, which should be combined with culture method to detect for infectious pathogen. The ETA is the desired method to collect the sputum of the patients.