哌拉西林-舒巴坦等七种药物对非发酵菌体外抗菌活性的研究

目的 评价哌拉西林-舒巴坦等7种药物对非发酵菌的体外抗菌活性.方法 采用微量肉汤稀释法测定哌拉西林-舒巴坦对细菌的体外抗菌作用.结果 广州地区6家医院共收集菌株770株,其中铜绿假单胞菌216株,鲍曼不动杆菌242株,嗜麦芽窄食单胞菌100株,洋葱伯克霍尔德菌119株,黄杆菌属57株,产碱杆菌属36株.对所有铜绿假单胞菌,哌拉西林-舒巴坦的敏感性最高(71.9%),而亚胺培南、头孢吡肟、头孢他啶、头孢哌酮-舒巴坦敏感性均低于50%.对亚胺培南不敏感的铜绿假单胞菌,哌拉西林-舒巴坦敏感性仍可达55.8%.对碳青霉烯敏感的鲍曼不动杆菌,哌拉西林-舒巴坦和头孢哌酮-舒巴坦敏感性最高,分别为71.0%和73.0%.对嗜麦芽窄食单胞菌,26%和20%的菌株对哌拉西林-舒巴坦和哌拉西林-他唑巴坦的最低抑菌浓度(MIC)≤16 mg/L.对洋葱伯克霍尔德菌,69%的菌株对哌拉西林-舒巴坦的MIC≤16 mg/L.对黄杆菌属和产碱杆菌属,哌拉西林-舒巴坦、头孢哌酮-舒巴坦和哌拉西林他唑巴坦3种加酶复合制剂敏感性最高,分别为70.2%、63.2%、57.9%和94.4%、94.4%、91. 7%.结论 哌拉西林-舒巴坦对多种非发酵菌尤其是碳青霉烯不敏感的铜绿假单胞菌具有良好的体外抗菌活性.     

泛耐药鲍曼不动杆菌院内感染的防治体会:附4例报告

病例：我院呼吸重症监护病房(RICU)在2005年7月．先后在4例患者痰液及分泌物中检测出5株鲍曼不动杆菌(Acinetobacter Baumanii),微生物药物敏感试验显示均对临床常用的抗菌药物耐药,包括阿米卡星、庆大霉素、派拉西林、头孢他啶、头孢哌酮、氨曲南、亚胺培南、环丙沙星、替卡西林/克拉维酸、头孢哌酮/舒巴坦、哌拉西林/他唑巴坦、头孢吡肟、帕尼培南和美罗培南。目前对现有临床常用的抗菌药物均耐药的菌株称为泛耐药(pan-drug resistant,PDR)株．故此次检出的鲍曼不动杆菌为PDR鲍曼不动杆菌。     

老年病房分离铜绿假单胞菌的耐药性分析

目的分析老年病房分离铜绿假单胞菌对临床常用抗菌药的耐药特征，为临床用药提供参考。方法收集我院老年病房2004年1月至2005年12月的住院患者分离菌株，药敏试验采用K-β扩散法。结果共分离出230株铜绿假单胞菌，其中224株来自痰标本。哌拉西林／他唑巴坦的敏感率最高，为64．8％，其他依次为阿米卡星、环丙沙星、头孢哌酮-舒巴坦；头孢他啶的耐药率最高，为50．9％，其他依次为哌拉西林、头孢吡肟、亚胺培南等。其对头孢他啶、头孢吡肟、亚胺培南的耐药率皆显著高于同期非老年病房分离株（P〈0．01）；多重耐药铜绿假单胞菌（MDRP）105株，占分离菌株的45．6％；71．5％的患者在标本分离的前2月里，接受过多种抗菌药物治疗。结论密切结合药敏试验，合理有序的应用抗生素、减轻抗生素的选择性压力，对于防治铜绿假单胞菌的耐药及传播，控制老年病房的院内感染具有重要意义。     

老年下呼吸道感染患者肺炎克雷伯菌和大肠埃希菌耐药性分析

目的：监测老年下呼吸道感染患者肺炎克雷伯菌和大肠埃希菌的耐药性。为临床合理应用抗生素提供依据。方法：对我院下呼吸道感染患者中分离出的肺炎克雷伯菌和大肠埃希菌240株，以Kirby-Bauer(K-B)琼脂扩散法作药敏试验；以美国临床实验室标准委员会（NCCLS）1999年推荐的表型确认试验检测超广谱β－内酰胺酶（ESBLs）。结果：老年组和非老年组肺炎克雷伯菌和大肠埃希菌对14例抗生素的耐药率分别为阿莫西林93．2％和87．3％，哌拉西林57．1％和42．9％、头孢呋新51．4％和33．3％、头孢噻肟40．1％和17．5％、头孢他啶13．6％和3．2％、头孢曲松39．0％和17．5％、头孢哌酮37．3％和15．9％，头孢吡肟10．2％和3．2％、阿米卡星47．5％和34．9％，环丙沙星54．2％和38．1％、亚胺培南15．9％、头孢吡肟10．2％和3．2％、阿米卡星47．5％和34．9％、环丙沙星54．2％和38．1％，亚胺培南0和0、头孢哌酮／舒巴坦0和0、哌拉西林／三唑巴坦1．1％和0、头孢美唑9．6％和4．8％。78株肺炎克雷伯菌和大肠埃希菌被证实为产ESBLs菌，ESBLs检测出率为32．5％（78／240），其中老年组ESBLs检出率为38．4％（68／177），非老年组ESBLs检出率为15．9％（10／63）。亚胺培南，头孢哌酮／舒巴坦，哌拉西林／三唑巴坦和头孢美唑对产ESBLs菌的耐药率最低，分别为0、0、2．6％和12．8％。结论：老年下呼吸道感染患者肺炎克雷伯菌和大肠埃希菌的耐药率和ESBLs检出率均显著高于非老年患者；亚胺培南，头孢哌酮／舒巴坦、哌拉西林／三唑巴坦和头孢美唑是治疗由产ESBLs菌引起感染的有效抗生素。     

184株肺炎克雷伯菌耐药性分析

目的探讨肺炎克雷伯菌对抗生素的耐药性，指导临床合理用药。方法应用Whonet5分析我院近3年住院呼吸道感染病人晨痰分离的184株肺炎克雷伯菌的药敏结果。结果三年间分离出184株住院呼吸道感染病人对15种常用抗生素平均耐药率为52．66％；对氨苄西林、头孢唑啉、头孢呋辛钠、头孢噻肟钠、头孢曲松、头孢他啶、头孢吡肟、氨曲南、亚胺培南耐的耐药率分别为100％、60．4％、59．6％、63．7％、58．4％、58．8％、49．3％、55％、11．3％；对阿莫西彬克拉维酸、头孢哌酮／舒巴坦、哌拉西彬他唑巴坦的耐药率分别为57．4％、26％、15％；对左旋氧氟沙星、环丙沙星耐药率分别为62％、68％；对阿米卡星耐药率为35％。结论肺炎克雷伯菌目前对亚胺培南耐药率最低、对阿米卡星和哌拉西林／他唑巴坦敏感，对其他抗生素均已高度耐药；重视细菌培养，合理使用抗生素，有利于控制耐药菌的产生。     

老年VAP嗜麦芽寡养单胞菌感染及耐药性分析

目的研究老年VAP嗜麦芽寡养单胞菌(SMA)感染及耐药特征。方法从161例老年患者分离的30株嗜麦芽寡养单胞菌采用纸片扩散法进行药敏试验,并对抗生素耐药结果进行回顾性分析。结果30株嗜麦芽寡养单胞菌对氨苄西林、亚胺培南、美罗培南、头孢唑啉、氨曲南、庆大霉素、阿米卡星高度耐药(100%,96.67%,96.67%,93.33%,80.00%,73.33%);对头胞吡肟,头胞他啶,头胞噻肟耐药率较高(50.00%,50.00%and60.00%),对左氧氟沙星,环丙沙星耐药率接近50%(40.00%,46.67%);但对复方新诺明、头孢哌酮/舒巴坦、哌拉西林/他唑巴坦耐药率较低(3.33%, 10.00 %,16.67%)。结论嗜麦芽寡养单胞菌对常用抗菌药物呈多重耐药,在老年VAP感染已十分严重,它的首选药物为复方新诺明、头孢哌酮/舒巴坦、哌拉西林/他唑巴坦。     

临床常见革兰阴性细菌的分布及耐药性分析

目的了解院内革兰阴性细菌的分布及耐药性特点。方法收集本院2004年7月～2006年7月各类临床标本分离出的革兰阴性细菌，采用K-B纸片琼脂扩散法进行药敏试验，分析其临床分布及耐药性。结果共分离出1271株革兰阴性细菌，以大肠埃希菌、克雷伯菌属和铜绿假单胞菌为主要病原菌，标本主要分布于痰、咽拭子和尿液中，病区主要集中于ICU室、神经外科和肺科。超广谱β-内酰胺酶（ESBLs）在大肠埃希菌、克雷伯菌属和变形杆菌属的检出率分别为38．4％、31．7％和25．5％。亚胺培南和美罗培南对肠杆菌科细菌、产ESBLs菌株和不动杆菌属的抗菌活性最强，耐药率为0-5．6％，铜绿假单胞菌对两药的耐药率为29．8％和27．2％；嗜麦芽窄食单胞菌对两药物高度耐受，耐药率均为95．7％，但对环丙沙星、头孢哌酮／舒巴坦和替卡西林／克拉维酸较敏感。结论大肠埃希菌、克雷伯菌属和铜绿假单胞菌为本院最常见革兰阴性细菌，亚胺培南和美罗培南对除嗜麦芽窄食单胞菌外的其他革兰阴性细菌具有较好的抗菌活性，其他抗菌药物的抗菌活性相对较低。     

嗜麦芽窄食单胞菌医院感染肺炎28例临床分析

目的探讨嗜麦芽窄食单胞菌的易感因素及耐药性问题。方法对2003年1月至2007年12月由嗜麦芽窄食单胞菌引起医院感染肺炎28例临床资料进行回顾性分析。结果28例患者平均住院56．43天,发生混合感染23例（82．14％）,死亡8例（28．57％）,侵袭性操作24例（85．71％）,对多种抗生素耐药,对环丙沙星的敏感性在70％以上。结论有严重基础疾病者滥用抗生素,应用免疫抑制剂,进行侵袭性操作,住院时间长等可致嗜麦芽窄食单胞菌感染,该菌对三代头孢广泛耐药,亚胺培南天然耐药,临床可选用环丙沙星联合头孢吡肟或阿莫西林克拉维酸或头孢哌酮舒巴坦可取得一定疗效。     

湖北地区2000～2007年铜绿假单胞菌临床分离株的耐药性分析

目的了解湖北地区临床分离的铜绿假单胞菌的耐药变迁,为临床合理使用抗生素提供依据。方法综合分析湖北地区17家医院2000～2007年的铜绿假单胞菌分离情况及其对各种抗生素的耐药率。结果湖北地区铜绿假单胞菌的年分离量和对各抗生素的耐药率基本呈逐年上升的趋势,对头孢唑啉、头孢呋辛的耐药率几乎达100％,对头孢曲松、头孢噻肟的耐药率〉50％,对庆大霉素、加替沙星的耐药性大大增加（耐药率在40％～50％之间）,对环丙沙星、左氧氟沙星、氨曲南、哌拉西林、他唑巴坦保持中度敏感性（耐药率在30％--40％之间）,对阿米卡星、头孢哌酮／舒巴坦、头孢他啶、头孢吡肟、亚氨培南、美洛培南保持相对较好的敏感性（耐药率〈30％）。结论铜绿假单胞菌对各种抗生素的耐药性逐年增加,临床上应选择敏感性相对较好的药物作为铜绿假单胞菌的经验用药,以避免医疗成本的浪费及耐药性加剧。     

267株鲍曼不动杆菌感染临床分布与耐药性分析

目的了解鲍曼不动杆菌的临床分布及其对常用抗牛素的耐药状况,为临床使用抗牛素治疗提供依据。方法对我院2009年1月～2009年12月住院患者送检标本分离的287株鲍曼不动杆菌的分布及药敏结果进行回顾性分析。结果267株鲍曼不动杆菌大多分离自痰液,主要来自于ICU病房;鲍曼不动杆菌对头孢西丁耐药率最高,为100％,依次是氨曲南（85．0％）、哌拉西林（76．8％）、哌拉西彬三唑巴坦（71．5％）、替卡西林／克拉维酸（70．8％）、头孢噻肟（67．8％）、头孢毗肟（65．2％）等。结论我院鲍曼不动杆菌耐药情况严重,治疗首选碳青霉烯类抗生素,其次可选用头孢哌酮／舒巴坦。     

抗菌药物用量与铜绿假单胞菌耐药相关性研究

目的 分析抗菌药物用量与铜绿假单胞菌耐药的关系,帮助临床合理使用抗菌药.方法 回顾性分析我院2001～2007年铜绿假单胞菌耐药率和具有抗假单胞菌活性抗菌药物的使用量,用药频度(DDDs)表示为每日每1 000例患者中消耗的限定日剂量数.结果 2001～2007年每年检出铜绿假单胞菌菌株数依次为150、208、165、205、264、271和262株.铜绿假单胞菌对多数抗菌药物的耐药率均较高.2005～2007年除头孢哌酮/舒巴坦的耐药率逐年下降外,其他抗菌药物耐药率均呈现增高趋势.2007年抗菌药物耐药率由低到高分别为:头孢哌酮/舒巴坦16.0%,头孢他啶33.1%,哌拉西林/三唑巴坦34.3%,头孢吡肟35.2%,左氧氟沙星37.7%,美罗培南39.3%,阿米卡星41.0%,亚胺培南44.7%.铜绿假单胞菌对哌拉西林/三唑巴坦的耐药率不仅与该药本身的DDDs显著相关(r=0.900,P=0.037),同时还与莫西沙星DDDs呈正相关(r=0.900,P=0.037),而与环丙沙星(r=-0.940,P=0.017)和阿米卡星(r=-0.900,P=0.037)的DDDs呈负相关;亚胺培南的耐药率与环丙沙星DDDs(r=-0.905,P=0.005)呈负相关;头孢他啶的耐药率与美罗培南(r=1.000,P=0.000)、哌拉西林/三唑巴坦(r=1.000,P=0.000)、莫西沙星(r=1.000,P=0.000)的DDDs呈正相关,而与环丙沙星(r=-0.968,P=0.032)、阿米卡星(r=-1.000,P=0.000)和奈替米星(r=-1.000,P=0.000)的DDDs呈负相关;左氧氟沙星的耐药率与亚胺培南/西司他丁的DDDs呈负相关(r=-0.988,P=0.012);阿米卡星的耐药率与环丙沙星的DDDs呈负相关(r=-0.964,P=0.000).结论 铜绿假单胞菌对某种抗菌药的耐药率主要与该药本身以及同类药物的使用量有关.尽量减少抗假单胞菌药物的使用,才能从根本上减轻细菌耐药.     

2009年山东大学附属省立医院细菌耐药性监测及分析

目的了解山东大学附属省立医院2009年临床分离菌株分布及耐药谱。方法收集山东大学附属省立医院2009年首次非重复分离株1 821株,细菌鉴定采用VITEK鉴定系统,药敏试验采用纸片扩散法,数据采用WHONET 5.4软件进行统计分析。结果大肠埃希菌和肺炎克雷伯菌对碳青霉烯类药物最敏感;柠檬酸杆菌属、沙雷菌属对碳青霉烯类药物敏感率较高,肠杆菌属和柠檬酸杆菌属对头孢西丁的耐药率分别为98.6%和85.7%,而沙雷菌属耐药率仅为30%;铜绿假单胞菌对哌拉西林/他唑巴坦、头孢吡肟、哌拉西林、头孢他啶、美罗培南、亚胺培南和头孢哌酮/舒巴坦较敏感,对其他药物敏感率均〈70%;鲍曼不动杆菌对亚胺培南、美罗培南敏感率为82.3%、73.2%,对头孢哌酮/舒巴坦耐药率为11.6%,对其他药物耐药率在15.0%~67.8%;葡萄球菌对万古霉素和利奈唑胺100%敏感,耐甲氧西林金黄色葡萄球菌和耐甲氧西林凝固酶阴性葡萄球菌检出率分别为45.0%和86.8%;屎肠球菌和粪肠球菌对万古霉素和利奈唑胺最敏感。结论肠杆菌科细菌对碳青霉烯类药物仍最为敏感,但不发酵糖菌对其耐药率升高;葡萄球菌属中均未发现耐万古霉素菌株。     

Comparative in vitro activity of cefepime against strains isolated from intensive care and haematology patients

The aim of the study was to evaluate cefepime, a "fourth generation" cephalosporin, for its in vitro activity in comparison with 5 other broad spectrum antibiotics against clinical isolates from ICU and haematology patients. The strains were isolated from blood (8%), lower respiratory tract (41%), upper respiratory tract (14%), urine (20%) and other sites (17%). They were divided into: 28 non-inducible Enterobacteriaceae, 35 inducible Enterobacteriaceae, 20 non-fermenters, 10 S. aureus and 10 Streptococcus spp. The MIC-values were determined by E-test. Overall, the rank order of susceptibility was cefepime (93%), imipenem (90%), piperacillin-tazobactam (81%), ciprofloxacin (79%), ceftriaxone (75%) and ceftazidime (74%). Only cefepime was able to inhibit all inducible Enterobacteriaceae. Against Pseudomonas aeruginosa, cefepime had the same activity as ceftazidime. With the exception of ceftazidime (65%), all beta lactams demonstrated good activity against Gram positive cocci. The excellent activity against most Gram negative and Gram positive pathogens suggests that cefepime may be useful in the treatment of serious infections in the described patient population.     

我院近3年下呼吸道革兰阴性杆菌耐药性监测

目的 调查我院近3年下呼吸道革兰阴性杆菌的耐药情况.方法 使用MIC法对我院下呼吸道感染住院患者的痰液标本中临床分离的926株革兰阴性杆菌进行药敏试验,并用WHONET 5.4软件进行数据分析.结果 926株革兰阴性杆菌中最常见的菌种依次为大肠埃希菌(29.7%)、肺炎克雷伯菌(23.7%)、铜绿假单胞菌(14.3%)、鲍曼不动杆菌(12.1%).大肠埃希菌、肺炎克雷伯菌对多黏菌素B、亚胺培南、美罗培南和咪诺环素保持高度敏感,耐药菌率在10%以内,对阿米卡星、哌拉西林/三唑巴坦、头孢哌酮/舒巴坦、头孢他啶及头孢匹肟的耐药率为30%以内,对其余所检测药物的耐药率均在30%以上.铜绿假单胞菌对多黏菌素B和咪诺环素;而亚胺培南,美罗培南、哌拉西林/三唑巴坦,头孢哌酮/舒巴坦和阿米卡星耐药率低于30%{鲍曼不动杆菌耐药情况比较严重,只有多黏菌素B、头孢哌酮/舒巴坦高度敏感,耐药率在10%以内,对亚胺培南和美罗培南的耐药率在20%以内,对其余所检测药物的耐药率均在30%到60%以上.结论 本研究结果对我院革兰阴性杆菌感染的经验用药治疗有重要参考价值.     

PCR identification and automated ribotyping of Pseudomonas aeruginosa clinical isolates from intensive care patients

Nosocomial isolates of Pseudomonas aeruginosa exhibit high rates of resistance to antibiotics, and are often multidrug resistant. P. aeruginosa clinical isolates (n = 56) were obtained from ICU patients in a hospital in Pakistan over a 3-y period. Antimicrobial susceptibility of the 56 P. aeruginosa clinical isolates was investigated using 7 antibiotics and the resistance rates were as follows: aztreonam (68% resistant), ceftazidime (67%), imipenem (66%), ofloxacin (59%), amikacin (56%), gentamicin (44%), and piperacillin-tazobactam (27%) (p < 0.01). In addition, 55% of the P. aeruginosa clinical isolates were resistant to 4 or more antibiotics. Imipenem-resistant strains were frequently associated with ceftazidime, ofloxacin, aztreonam, and more strikingly, amikacin resistance (p < 0.05). PCR (using P. aeruginosa-specific primers VIC1 + VIC2 and P1 + P2, respectively) was highly specific and sensitive, and was positive for all 56 P. aeruginosa isolates tested. Automated ribotyping was used to investigate the clonal diversity of the 56 P. aeruginosa isolates. Automated ribotyping indicated that the clinical isolates were clonally related and could be clustered into 4 major ribogroups based on their similarity index, with ribogroup II being the dominant one. The P. aeruginosa isolates in ribogroup II were correlated with their antibiotic resistance pattern and, interestingly, there seemed to be a gradual acquisition of multiple antibiotic resistance associated with the isolates within this group over time. The ribotyping data, together with the antibiotic resistance profile, provide valuable molecular epidemiology information for the control of hospital-acquired P. aeruginosa infections.     

头孢哌酮－舒巴坦体外抗菌作用研究

为评价头孢哌酮（ｃｅｆｏｐｅｒａｚｏｎｅ，ＣＰＺ）－舒巴坦（ｓｕｌｂａｃｔａｍ，ＳＢＴ）合剂的体外抗菌作用，观察了ＣＰＺ－ＳＢＴ对１１４６株临床分离菌的抗菌活性，并与ＣＰＺ及其他抗菌药物进行比较。ＣＰＺ－ＳＢＴ对产β－内酰胺酶菌株的抗菌活性高于ＣＰＺ，在需氧革兰阴性杆菌８３４株中，对ＣＰＺ耐药者１６５株，其中９４株（５７．０％）对ＣＰＺ－ＳＢＴ呈现敏感。ＣＰＺ－ＳＢＴ扩大了抗菌谱，其对不动杆菌属、脆弱类杆菌等具有良好抗菌作用。与受试的其他抗菌药物相比，该合剂对肠杆菌科、绿脓杆菌和不动杆菌属等的抗菌活性与头孢他啶、阿米卡星、环丙沙星相仿，较亚胺培南略差；对脆弱类杆菌等厌氧菌的作用则与亚胺培南、替门汀和甲硝唑相仿。上述结果提示ＣＰＺ－ＳＢＴ为一新的广谱抗菌药，具有良好的临床应用前景，可用于耐头孢哌酮革兰阴性杆菌（包括绿脓杆菌）而对本合剂呈现敏感菌所致的严重感染的治疗。     

Antimicrobial resistance among clinical isolates of Pseudomonas aeruginosa from patients in a teaching hospital, Riyadh, Saudi Arabia, 2001-2005

Antimicrobial resistance to nine anti-pseudomonal agents (azteronam, ceftazidime, cefepime, piperacillin/tazobactam, imipenem, meropenem, ciprofloxacin, amikacin and gentamicin), the magnitude of multidrug resistance, associated underlying conditions, and mortality among patients with Pseudomonas aeruginosa isolates from King Khalid University Hospital, Riyadh, Saudi Arabia from 2001 to 2005 were determined. The results showed that antimicrobial resistance among P. aeruginosa is gradually increasing for most anti-pseudomonal agents, particularly aztreonam, ceftazidime, piperacillin/tazobactam and imipenem. There were 19 (3%) and 12 (2%) multidrug-resistant (MDR) P. aeruginosa patients in 2004 and 2005, respectively, and MDR P. aeruginosa was more commonly found in non-intensive care unit (ICU) patients. Most MDR isolates were from surgical and diabetic patients. The mortality rate was higher among ICU patients.     

1998年上海地区细菌耐药性监测

目的 对上海医院中临床分离菌进行耐药性监测,指导临床合理用药。方法 用Ｋｉｒｂｙ－Ｂａｕｅｒ法进行药敏试验,根据１９９７年ＮＣＣＬＳ判断结果。结果 临床分离菌中革兰阳性球菌有增多趋势。金黄色葡萄球菌（ＳＡ）和凝固酶阴性葡萄球菌（ＣＮＳ）中耐甲氧西林ＳＥＡ（ＭＲＳＡ）和耐甲氧西林ＣＮＳ（ＭＲＣＮＳ）分别约占７０．７％和５４．９％但对万古霉素均敏感,肠球菌属中万古霉素耐药株约５％,克雷白菌属,沙雷菌属     

Antimicrobial activity of doripenem against Gram-negative pathogens: results from INVITA-A-DORI Brazilian study

In vitro activity of doripenem and comparator antimicrobial agents was evaluated against Gram-negative bacilli recently isolated from Brazilian private hospitals that were enrolled in the INVITA-A-DORI Brazilian Study. A total of 805 unique Gram-negative bacilli were collected from patients hospitalized at 18 medical centers between May/08 and March/09. Each hospital was asked to submit 50 single Gram-negative bacilli isolated from blood, lower respiratory tract or intraabdominal secretions. Bacterial identification was confirmed and antimicrobial susceptibility testing was performed using Clinical Laboratory Standards Institute (CLSI) microdilution method at a central laboratory. CLSI M100-S21 (2011) or US-FDA package insert criteria (tigecycline) was used for interpretation of the antimicrobial susceptibility results. Doripenem was as active as meropenem and more active than imipenem against E. coli and K. pneumoniae isolates. A total of 50.0% of Enterobacter spp. isolates were resistant to ceftazidime but 85.7% of them were inhibited at doripenem MICs < 1 μg/mL. Polymyxin B was the only agent to show potent activity against Acinetobacter spp. (MIC50/90, < 0.5/1 μg/mL) and P. aeruginosa (MIC50/90, 1/2 μg/mL). Although high rates of imipenem (53.1%) and meropenem (44.5%) resistance were detected among P. aeruginosa, doripenem showed MIC50 of 16 μg/mL against imipenem-resistant P. aeruginosa and inhibited a greater number of imipenem-resistant P. aeruginosa (10.5%) at MIC values of < 4 μg/mL than did meropenem (0.0%). In this study, doripenem showed similar in vitro activity to that of meropenem and retained some activity against imipenem-resistant P. aeruginosa isolated from Brazilian medical centers.