目的  探讨儿童呼吸机相关性肺炎（ＶＡＰ）的主要病原菌，指导临床治疗和预防。方法  ３４例ＶＡＰ患儿作气道分泌物细菌或霉菌培养，同时作细菌药敏试验。结果  分离出病原菌１０６株，其中Ｇ－杆菌７２株（６７．９％），依次为不动杆菌、铜绿假单胞菌、肺炎克雷白杆菌、肠杆菌属、嗜麦芽假单胞菌、大肠埃希氏菌等；Ｇ＋球菌６株（５．７％），分别为甲型链球菌、金葡菌；真菌２８株（２６．４％ ）。对第三代头孢菌素、氨基糖甙类抗药性肠杆菌属为８０％ ，不动杆菌５０％ ；嗜麦芽假单胞菌对亚胺培南的抗药性为８８．９％；Ｇ＋球菌对青霉素耐药占８３．３％，对万古霉素１００％敏感。结论  ＶＡＰ的病原菌以Ｇ－杆菌为主，真菌感染也不容忽视。根据药敏合理选用抗生素，避免滥用抗生素，尤其是第三代头孢菌素。

OBJECTIVE: To study the characteristics of endotracheal pathogens in children with ventilator-associated pneumonia(VAP) in order to establish more e ffective treatment and prophylaxis regimens. METHODS: Endotr acheal tube secretion s were collected for bacterial and/ fungal culture and drug-sensitivity testing in 34 children with VAP. RESULTS: There were 106 bacterial strains cultured from the 34 patients. Seventy-two(67.9%) cultures yielded Gram-negative bacteria, of wh ic h 17 were Acinetobacter baumanii, 20 Pseudomonas aeruginosa, 17 Klebsiella pneum oniae, 6 Enterobacteriaceae, 4 Stenotrophomonas maltophilia and 8 Escherichia coli. There were 6(5.7%) Gram-positive cocci, including 5 type A Streptococcus a n d 1 Staphylococcus aureus. Twenty-eight cultures were positive for fungi. Sixte e n patients had mixed infections. Eighty percent of the Enterobacteriaceae and 50 % of the Acinetobacter baumanii were resistant to third generation cephalosporin s and aminoglycosides; 88.9% of the Stenotrophomonas maltophilia were resistant to imipenem, and 83.3% of the Gram-positive cocci to penicillin. CONCLUSIONS: Gra m-negative bacteria account for the majority of pathogens in children with VAP.Fungal infections should not be disregarded. Antibiotics should be appropriately used according to drug-sensitivity testing.