目的:监测2018年我国引起院内感染的主要病原菌的病原谱分布和对主要抗菌药物的敏感性。方法:回顾性收集来自全国11家教学医院的引起院内血流感染（BSI）、院内获得性肺炎（HAP）和院内腹腔感染（IAI）的病原菌。菌株经中心实验室复核后，对临床常见菌株进行抗菌药物药敏实验，采用琼脂稀释法或微量肉汤稀释法测定菌株的最低抑菌浓度（MIC），药敏折点采用美国临床和实验室标准协会（CLSI）2019年M100S（第29版）标准。数据分析采用WHONET-5.6软件。结果:共收集1 590例病例，包括BSI 831例，HAP 450例，IAI 309例。BSI最主要的致病菌是大肠埃希菌（29.2%，243/831）、肺炎克雷伯菌（16.2%，135/831）和金黄色葡萄球菌（10.1%，84/831）；IAI最主要的致病菌是大肠埃希菌（26.2%，81/309）、屎肠球菌（15.5%，48/309）和肺炎克雷伯菌（13.3%，41/309）；而HAP最主要致病菌是鲍曼不动杆菌（24.7%，111/450）、铜绿假单胞菌（20.7%，93/450）和肺炎克雷伯菌（16.2%，73/450）。金黄色葡萄球菌对替加环素、利奈唑胺、达托霉素和糖肽类抗生素均表现为敏感，对头孢洛林的敏感率为77.8%（105/135）。甲氧西林耐药的金黄色葡萄球菌（MRSA）的发生率为29.6%（40/135），低于甲氧西林耐药的凝固酶阴性葡萄球菌（MRCNS）的发生率（83.7%，41/49）。发现1株屎肠球菌对万古霉素和替考拉宁耐药（1.1%，1/95），1株粪肠球菌对利奈唑胺耐药（2.3%，1/43）。大肠埃希菌和肺炎克雷伯菌中超广谱β内酰胺酶的发生率分别为56.1%（193/344）和22.1%（55/249），碳青霉烯耐药株的发生率分别为4.1%（14/344）和22.9%（57/249），对头孢他啶/阿维巴坦的耐药率分别为2.3%（8/344）和2.0%（5/249），对黏菌素的耐药率分别为1.5%（5/344）和7.6%（19/249），均未检出替加环素耐药株。鲍曼不动杆菌除对黏菌素（99.5%，184/185）和替加环素（91.4%，169/185）表现出较高的敏感性，对其他抗菌药物均表现出较高的耐药率，碳青霉烯耐药株的发生率达到78.9%（146/185）。碳青霉烯耐药的铜绿假单胞菌发生率为36.7%（66/180）；黏菌素、阿米卡星和头孢他啶/阿维巴坦对铜绿假单胞菌表现出较强的抗菌活性，敏感率分别为100%（180/180）、93.3%（168/180）和85.6%（154/180）。结论:替加环素、黏菌素和头孢他啶/阿维巴坦对大部分院内感染常见革兰阴性杆菌表现出较强的体外抗菌活性。鲍曼不动杆菌耐药问题严重。碳青霉烯耐药的肠杆菌科细菌发生率继续升高，需要引起关注并进行持续监测。“,”Objective:To investigate the spectrum and antimicrobial resistance of major pathogens causing nosocomial infections in China, 2018.Methods:Non-duplicated nosocomial cases as well as pathogens causing bloodstream infections (BSI), hospital-acquired pneumonia (HAP) and intra-abdominal infections (IAI) from 11 teaching hospitals across China were collected. The minimum inhibitory concentrations (MICs) of clinically significant strains were determined by agar dilution method or broth microdilution method. The Clinical and Laboratory Standards Institute (CLSI) M100-S29 criteria were used for interpretation, and the WHONET-5.6 software was used in data analysis.Results:A total of 1 590 cases were collected, including 831 cases from BSI, 450 cases from HAP and 309 cases from IAI. The most prevalent pathogens causing BSI were n Escherichia coli (29.2%, 243/831), n Klebsiella pneumoniae (16.2%, 135/831) and n Staphylococcus aureus (10.1%, 84/831); the most prevalent pathogens causing IAI were n E. coli (26.2%, 81/309), n Enterococcus faecium (15.5%, 48/309) and n K. pneumoniae (13.3%, 41/309); while n Acinetobacter baumanii (24.7%, 111/450), n Pseudomonas aeruginosa (20.7%, 93/450) and n K. pneumoniae (16.2%, 73/450) were dominated in HAP. All n S. aureus were susceptible to tigecycline, linezolid, daptomycin and glycopeptides; 77.8% (105/135) of n S. aureus strains were susceptible to ceftaroline. Methicillin-resistant n S. aureus (MRSA) accounted for 29.6% (40/135) of all the n S. aureus, and was lower than the accounted rate of methicillin-resistant coagulase-negative n Staphylococcus (MRCNS) (83.7%, 41/49). One n E. faecium strain (1.1%, 1/95) resistant to vacomycin and teicoplanin and one n E. faecalis strain (2.3%, 1/43) resistant to linezolid was found. The prevalence of extended-spectrum β-lactamase (ESBL) was 56.1% (193/344) in n E. coli and 22.1% (55/249) in n K. pneumonia; the rate of carbapenem resistant n E. coli and n K. pneumonia was 4.1% (14/344) and 22.9% (57/249), respectively; the percentage of ceftazidime/avibactam resistant n E. coli and n K. pneumonia was 2.3% (8/344) and 2.0% (5/249), respectively; the percentage of colistin resistant n E. coli and n K. pneumonia was 1.5% (5/344) and 7.6% (19/249), respectively; no n E. coli and n K. pneumonia strains were found resistant to tigecycline. The rate of carbapenem resistant n A. baumanii and n P. aeruginosa were 78.9% (146/185) and 36.7% (66/180), respectively. n A. baumanii showed low susceptibility to the antimicrobial agents except colistin (99.5%, 184/185) and tigecycline (91.4%, 169/185). Colistin, amikacin and ceftazidime/avibactam demonstrated high antibacterial activity against n P. aeruginosa with susceptility rate of 100% (180/180), 93.3% (168/180) and 85.6% (154/180), respectively.n Conclusions:Nosocomial Gram-negative pathogens show high susceptibilities to tigecycline, colistin and ceftazidime/avibactam n in vitro. Antimicrobial resistance in n A. baumannii is a serious problem. The prevalence of carbapenem-resistant n Enterobacteriaceae has increased, which should be monitored continuously in China.n