目的：了解肿瘤患者经各种治疗后病原菌感染状况及对抗生素的敏感性。方法：对１１０例肿瘤患者治疗前、后的体液、分泌物标本进行细菌学分析；对治疗后所分离的部分菌株进行药敏感试验。结果：治疗前分离出革兰阳性菌３５株，阳性率为３０４３％；革兰阴性菌４１株，阳性率为３５１５％；类酵母菌１２株，阳性率为１０４３％。治疗后分离出革兰阳性菌３６株，阳性率为３１３０％；革兰阴性菌６５株，阳性率为５６５２％；类酵母菌３２株，阳性率为２７８３％。与治疗前相比，革兰阴性菌、类酵母菌感染明显上升（Ｐ＜００１），且革兰阴性菌中以大肠埃希氏菌和铜绿假单胞菌占优势。结论：肿瘤患者经各种治疗后，条件致病菌和类酵母菌的感染率正逐渐升高。 Objective: To understand the infection status of pathogens and the sensitivity to antibiotics in cancer patients after various treatments. Methods: Bacteriological analysis of body fluids and secretions before and after treatment was performed on 110 patients with tumors. Drug susceptibility tests were performed on some strains isolated after treatment. Results: 35 strains of Gram-positive bacteria were isolated before treatment, with a positive rate of 3043%; 41 strains of Gram-negative bacteria, with a positive rate of 3515%; 12 strains of yeast-like strains, with a positive rate of 1043%. After treatment, 36 strains of Gram-positive bacteria were isolated, with a positive rate of 3130%; 65 strains of Gram-negative bacteria were positive, the positive rate was 5652%; 32 strains were yeast, and the positive rate was 2783%. Compared with before treatment, gram-negative and yeast-like infections increased significantly (P<001), and Escherichia coli and Pseudomonas aeruginosa dominated the gram-negative bacteria. Conclusion: The infection rate of conditional pathogens and yeasts is gradually increasing after various treatments for tumor patients.