分析肺恶性肿瘤继发下呼吸道感染的病原学特点、耐药性和感染相关危险因素。

选择2018年7月至2021年12月南通大学第二附属医院和苏州大学第一附属医院住院行肺泡灌洗外送宏基因组二代测序(metagenomic next-generation sequencing, mNGS)患者158例。肺恶性肿瘤42例分为观察组，非肺恶性肿瘤116例分为对照组。收集肺泡灌洗液，进行病原菌鉴定及药敏试验。采用单因素和多因素分析感染相关危险因素。应用对数秩检验比较两组存活率。

观察组发生下呼吸道感染31例(73.81%)；对照组发生下呼吸道感染101例(87.07%)。观察组多种微生物G^－和真菌感染11例。观察组常见流感嗜血杆菌、白色念珠菌、屎肠球菌和铜绿假单胞菌。观察组发生下呼吸道感染耐药菌9例(29.03%)；耐药病原体铜绿假单胞菌常见。Logistic回归分析显示，胸腔积液和肿瘤分期是肺恶性肿瘤继发下呼吸道感染危险因素(P<0.05)。随访期间观察组死亡21例(50.00%)。感染者生存率降低(P<0.05)。

肺恶性肿瘤常见病原体为G^－，胸腔积液和肿瘤分期是肺恶性肿瘤发生下呼吸道感染的危险因素，导致肺恶性肿瘤总体生存率降低。

To analyze the microbiological characteristics, drug resistance, and infection-related risk factors of lower respiratory tract infection in patients with lung malignancies.

All of 158 patients who were hospitalized in the Second Affiliated Hospital of Nantong University and the First Affiliated Hospital of Soochow University from July 2018 to December 2021 were retrospectively analyzed. Metagenomic next-generation sequencing of patients was tested in the alveolar lavage. 42 cases of lung malignant tumor were divided into observation group, 116 cases of non-lung malignant tumor were divided into control group. The patients′bronchoalveolar lavage fluid was collected, and the pathogen identification and drug sensitivity test were carried out. Univariate and multivariate analyses were used to evaluate related risk factors of infections factors. Survival of lung malignancies patients with infected and non-infected was compared using the log-rank test.

In the observation group, 31 patients(73.81%) developed lower respiratory tract infection; in the control group, 101 patients(87.07%) developed lower respiratory tract infection. In the observation group, the infection patterns of various microorganisms were dominated by a mixture of Gram-negative bacteria and fungi in 11 cases. In the observation group, the most common pathogens were Haemophilus influenzae, Candida albicans, Enterococcus faecium, and Pseudomonas aeruginosa. Among the 31 patients with lower respiratory tract infection in the observation group, drug-resistant bacteria were detected in 9 patients(29.03%); the most common drug-resistant pathogen was Pseudomonas aeruginosa. Binary logistic regression analysis showed that pleural effusion and tumor stage were independent risk factors for lower respiratory tract infection in patients with lung cancer (P<0.05). A total of 21 patients (50.00%) died during the follow-up period. Patients in the infection(+ ) group had significantly lower overall survival compared with those in the infection(-) group (P<0.001).

Gram-negative bacteria are the majority of pathogens documented in patients with lung malignancies. Pleural effusion and tumor stage are independent risk factors for lower respiratory tract infection in patients with lung cancer, and infection reduces overall survival in patients with lung cancer.