目的：调查儿科血液病房血培养病原菌分布及其变迁，分析主要病原菌的耐药性及导致血培养阳性败血症的相关危险因素。方法：对该院2008~2011年自儿科血液病房的2358份血培养标本分离出的病原菌种类、药敏结果及临床资料整理分析。结果：共分离出110株病原菌,前三位依次为大肠埃希菌16株、铜绿假单胞菌12株、表皮葡萄球菌8株。4年中革兰阳性菌的构成比降低，而革兰阴性菌的构成比升高。耐甲氧西林的凝固酶阴性葡萄球菌（MRCNS）和金黄色葡萄球菌（MRSA）检出率分别为69%和43%，但均对万古霉素敏感。产超广谱β内酰胺酶（ESBL）的大肠埃希菌和肺炎克雷伯菌分别为69%和62%，但均对碳青酶烯类抗生素敏感。恶性肿瘤性疾病是血培养阳性的危险因素（OR=3.564, P<0.05）。结论：儿科血液病房儿童血流感染的病原菌种类繁多，构成比不断变化，耐药率高。恶性肿瘤性疾病是血培养阳性的危险因素。

OBJECTIVE: To investigate the species and percentage changes of pathogens in blood cultures from the pediatric hematology ward, and to analyze the drug resistance of main pathogens and the risk factors for positive blood culture (sepsis). METHODS: A retrospective analysis was performed to analyze the species and drug sensitivity of the pathogens isolated from 2358 blood cultures from the pediatric hematology ward of the West China Second University Hospital between 2008 and 2011, as well as the related clinical data. RESULTS: A total of 110 strains of pathogens were isolated, with Escherichia coli (16 strains), Pseudomonas aeruginosa (12 strains) and Staphylococcus epidermidis (8 strains) being the most common ones. From 2008 to 2011, the percentage of Gram-positive bacteria decreased, while the percentage of Gram-negative bacteria increased. The detection rates of methicillin-resistant coagulase-negative Staphylococci and methicillin-resistant Staphylococcus aureus were 69% and 43% respectively, but both were sensitive to vancomycin. The detection rates of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and ESBL-producing Klebsiella pneumoniae were 69% and 62% respectively, but both were sensitive to imipenem and meropenem. Malignant tumor was a risk factor for positive blood culture (OR=3.564, P<0.05). CONCLUSIONS: A wide range of pathogens are responsible for bloodstream infection in the pediatric hematology ward and the percentages of bacteria are changing; these pathogens have a high drug resistance rate. Malignant tumor is a risk factor for positive blood culture in the pediatric hematology ward.