To dynamically investigate the distribution and antimicrobial resistance profiles of bacteremia pathogens isolated from different regions in China in 2011, 2013 and 2016. Non-repetitive isolates from nosocomial bloodstream infections were retrospectively collected and detected for antimicrobial susceptibility tests (AST) by agar dilution or microbroth dilution methods. Whonet 5.6 was used to analyze the AST data. Among 2 248 isolates, 1 657 (73.7%) were Gram-negative bacilli and 591 (26.3%) were Gram-positive cocci. The top five bacteremia pathogens were as follows, Escherichia coli (32.6%, 733/2 248), Klebsiella pneumoniae (14.5%, 327/2 248), Staphylococcus aureus (10.0%, 225/2 248), Acinetobacter baumannii (8.7%, 196/2 248) and Pseudomonas aeruginosa (6.2%, 140/2 248). Colistin (96.5%, 1 525/1 581, excluding innate resistant organisms), tigecycline (95.6%, 1 375/1 438, excluding innate resistant organisms), ceftazidine/clavulanate acid (89.2%, 1 112 /1 246), amikacin (86.4%, 1 382/1 599) and meropenem (85.7%, 1 376/1 605) showed relatively high susceptibility against Gram-negative bacilli. While tigecycline, teicoplanin and daptomycin (the susceptibility rates were 100.0%), vancomycin and linezolid (the susceptibility rates were 99.7%) demonstrated high susceptibility against Gram-positive cocci. The prevalence of extended-spectrum β-lactamases (ESBLs)-producing Enterobacteriaceae were 50.6% (206/407), 49.8% (136/273) and 38.9% (167/429) in 2011, 2013 and 2016 respectively; carbapenem-non-susceptible Enterobacteriaceae were 2.2% (9/408), 4.0% (16/402) and 3.9% (17/439) in 2011, 2013 and 2016 respectively; The prevalence of multidrug-resistant A. baumannii (MDRA) was 76.4% (55/72) in 2011, 82.7% (43/52) in 2013 and 87.5% (63/72) in 2016, respectively. The prevalence of multidrug-resistant P. aeruginosa (MDRP) was 9.8% (5/51) in 2011, 20.0% (7/35) in 2013 and 13.0% (7/54) in 2016, respectively. The prevalence of methicillin-resistant S. aureus (MRSA) was 51.9% (41/79) in 2011, 29.7% (19/64) in 2013 and 31.7% (26/82) in 2016, respectively. The prevalence of high level gentamicin resistance (HLGR) of Enterococcus faecium and Enterococcus faecalis were 43.2% (48/111) and 40.9% (27/66), respectively. The predominant organism of carbapenem-non-susceptible Enterobacteriaceae was K. pneumoniae with its proportion of 57.1% (24/42). Among 30 tigecycline-non-susceptible Enterobacteriaceae, K. pneumoniae was the most popular organism with 76.7% (23/30). Among 39 colistin-resistant Enterobacteriaceae, E. coli, Enterobacter cloacae and K. pneumoniae were constituted with the percent of 43.6 (17/39), 35.9 (14/39) and 15.4 (6/39), respectively. The Gram-negative bacilli (E. coli and K. pneumoniae were the major organisms) were the major pathogens of nosocomial bacteremia, to which tigecycline, colistin and carbapenems kept with highly in vitro susceptibility. Whereas, among the Gram-positive cocci, S. aureus was the top 1 isolated organism, followed by E. faecium, to which tigecycline, daptomycin, linezolid, vancomycin and teicoplanin kept with highly in vitro susceptibility. Isolation of colistin-resistant Enterobacteriaceae, tigecycline-non-susceptible Enterobacteriaceae, linezolid- or vancomycin-non-susceptible Gram-positive cocci suggests more attention should be paid to these resistant organisms and dynamic surveillance was essential.
动态监测2011 年、2013 年和2016 年我国不同地区医院内获得性血流感染病原菌分布及耐药进展趋势。从全国10 个城市回顾性收集血流感染病原菌非重复性株，采用琼脂稀释法或微量肉汤稀释法进行药物敏感性试验，采用Whonet 5.6 软件对药敏试验结果进行分析。收集的2 248 株血流感染病原菌中革兰阴性杆菌为1 657 株(占73.7%)，革兰阳性球菌为591 株 (占26.3%)。分离率排名前五的病原菌依次为大肠埃希菌 (32.6%，733 株/2 248 株)、肺炎克雷伯菌 (14.5%，327 株/2 248 株)、金黄色葡萄球菌 (10.0%，225 株/2 248 株)、鲍曼不动杆菌 (8.7%，196 株/2 248 株) 和铜绿假单胞菌 (6.2%，140 株/2 248 株)。血流感染分离的革兰阴性杆菌对抗菌药物体外敏感率较高的抗菌药物依次为粘菌素 (96.5%，1 525 株/1 581 株，不包括天然耐药菌株)、替加环素 (95.6%，1 375 株/1 438 株，不包括天然耐药菌株)、头孢他啶/克拉维酸 (89.2%，1 112 株/1 246 株)、阿米卡星 (86.4%，1 382 株/1 599 株) 和美罗培南 (85.7%，1 376 株/1 605 株)；革兰阳性球菌对抗菌药物体外敏感率较高的抗菌药物依次为替加环素、替考拉宁和达托霉素 (敏感率均为100.0%)、万古霉素和利奈唑胺 (敏感率均为99.7%)。2011 年、2013 年和2016 年产超广谱β-内酰胺酶肠杆菌科细菌分离率分别为50.6% (206 株/407 株)、49.8% (136 株/273 株) 和38.9% (167 株/429 株)；碳青霉烯不敏感肠杆菌科细菌分离率分别为2.2% (9 株/408 株)、4.0% (16 株/402 株) 和3.9% (17 株/ 439 株)；多重耐药鲍曼不动杆菌分离率分别为76.4% (55 株/72 株)、82.7% (43 株/52 株) 和87.5% (63 株/72 株)，多重耐药铜绿假单胞菌分离率分别为9.8% (5 株/51 株)、20.0% (7 株/35 株) 和13.0% (7 株/54 株)；甲氧西林耐药金黄色葡萄球菌的分离率分别为51.9% (41 株/79 株)、29.7% (19 株/64 株) 和31.7% (26 株/82 株)。屎肠球菌和粪肠球菌中高水平庆大霉素耐药株分离率分别为43.2% (48 株/111 株) 和40.9% (27 株/66 株)。碳青霉烯不敏感肠杆菌科细菌中肺炎克雷伯菌居首位，占57.1% (24 株/42 株) 。肠杆菌科细菌中分离出30 株替加环素不敏感株，其中肺炎克雷伯菌占76.7% (23 株/30 株)；分离出粘菌素耐药肠杆菌科细菌39 株，其中大肠埃希菌、阴沟肠杆菌和肺炎克雷伯菌分别占43.6% (17 株/39 株)、35.9% (14 株/39 株) 和15.4% (6 株/39 株)。医院获得性血流感染病原菌主要为革兰阴性杆菌 (以大肠埃希菌和肺炎克雷伯菌为主)，其对替加环素、粘菌素和碳青霉烯类药物的敏感率较高；革兰阳性球菌中分离率最高的为金黄色葡萄球菌，其次为屎肠球菌，这两种细菌对替加环素、达托霉素、利奈唑胺、万古霉素和替考拉宁的敏感率较高。粘菌素耐药肠杆菌科细菌、替加环素不敏感肠杆菌科细菌、利奈唑胺或万古霉素不敏感革兰阳性球菌的分离，警示临床高度关注，仍需动态监测耐药进展趋势。.
Keywords: antimicrobial resistance; bacteremia; bloodstream infections; pathogen distribution.