头孢地尼等抗生素对社区获得性呼吸道感染常见病原菌的体外抗菌活性研究

目的：测定头孢地尼对临床常见社区获得性呼吸道感染病原菌的体外抗菌活性,并与头孢呋辛、头孢克洛、阿奇霉素和氨苄西林比较.方法：琼脂稀释法测定抗生素的最低抑菌浓度（MIC）.结果：200株细菌测定结果表明：头孢地尼对甲氧西林敏感的金黄色葡萄球菌（MSSA）的敏感率为100%,抗菌活性与头孢呋辛、头孢克洛相似,明显强于阿奇霉素;青霉素敏感的肺炎链球菌（PSSP）对3种头孢菌素100%敏感,头孢地尼的MIC90值为0.25mg/L,与头孢呋辛相似;头孢地尼对革兰阴性菌的抗菌活性较高,对ESBLs阴性的肺炎克雷伯菌、流感嗜血杆菌、卡他莫拉菌的MIC90值分别为0.25、1、0.25mg/L,敏感率范围达97.2%～100%.流感嗜血杆菌对氨苄西林产生耐药性,敏感率仅达86.1%,但其MIC50值最低为0.06mg/L.耐甲氧西林的金黄色葡萄球菌（MRSA）、青霉素耐药的肺炎链球菌（PRSP）及产ESBLs的肺炎克雷伯菌对4种抗生素均耐药;头孢地尼对青霉素中介的肺炎链球菌（PISP）的抗菌活性比受试第二代头孢菌素和阿奇霉素强.结论：头孢地尼对革兰阳性球菌及革兰阴性菌均有较理想的体外抗菌活性,可作为治疗社区获得性呼吸道感染的较好选择.     

头孢西酮的体外抗菌活性

目的 评价头孢西酮的体外抗菌活性.方法 采用琼脂对倍稀释法测定头孢西酮对568株临床分离菌的体外抗菌活性,并与相关抗菌药进行比较;测定头孢西酮的杀菌浓度和杀菌曲线以及培养条件对头孢西酮抗菌活性的影响.结果 在需氧革兰阳性菌中,头孢西酮对甲氧西林敏感金葡菌(MSSA)和甲氧西林敏感凝同酶阴性葡萄球菌(MSCNS)、青霉素敏感肺炎链球菌(PSSP)以及β溶血性链球菌均有很好的抗菌活性,MIC90≤1 mg/L.头孢西酮对流感嗜血杆菌和卡他莫拉菌的MIC90为8 mg/L.在革兰阴性菌中,头孢西酮对非产ESBLs的肺炎克雷伯菌、大肠埃希菌和奇异变形杆菌仍保持很好的抗菌活性.头孢西酮对产ESBLs的肺炎克雷伯菌、大肠埃希菌、摩根摩根菌、沙雷菌、阴沟肠杆菌和不发酵糖革兰阴性菌中铜绿假单胞菌、不动杆菌属均无抗菌活性.培养基pH值的改变、细菌接种量、血清含量改变对该药抗菌活性无明显影响.结论 头孢西酮对社区感染常见病原菌均有较好的抗菌活性.     

米诺环素和多西环素对表皮葡萄球菌的体外抗菌活性比较

目的观察米诺环素和多西环素对表皮葡萄球菌的体外抗菌活性。方法采用二倍琼脂稀释法对124株表皮葡萄球菌进行米诺环素和多西环素体外抗菌实验,并进行两种抗生素的抗菌效果对比。结果米诺环素和多西环素均有很好的抗菌效果,米诺环素和多西环素对81株甲氧西林敏感的表皮葡萄球菌(MSSE)的最低抑菌浓度(MIC90)分别为1 mg/L和2 mg/L。对43株耐甲氧西林表皮葡萄球菌(MRSE)的MIC90均为2 mg/L。结论表皮葡萄球菌对米诺环素和多西环素的敏感率均为100%,表明米诺环素和多西环素均有较好的抗菌效果。     

加替沙星体外抗菌作用研究

目的：评价加替沙星的体外抗菌作用。方法：以琼脂稀释法测定加替沙星对临床分离菌的最低抑菌浓度(MIC)，并与有关抗菌药进行比较。测定加替沙星的杀菌作用，以及各种培养条件对加替沙星抗菌活性的影响。结果：加替沙星对临床分离菌1192株MIC测定结果显示该药具广谱抗菌作用。对甲氧西林敏感金黄色葡萄球菌(MSSA)、肺炎链球菌、溶血性链球菌、流感嗜血杆菌具高度抗菌活性，MIC90≤0．25mg／L。但对甲氧西林耐药葡萄球菌(MRS)和肠球菌属的作用差。对肠杆菌科细菌的大多数菌株具良好抗菌作用，其中对肺炎克雷伯菌、沙雷菌属、普通变形杆菌、沙门菌属、志贺菌属的MIC90≤2mg／L。但大肠埃希菌的敏感性较差。该药对铜绿假单胞菌、嗜麦芽窄食单胞菌亦具良好抗菌作用，不动杆菌属对其敏感性较差。加替沙星对脆弱拟杆菌、消化链球菌等厌氧菌亦具高度抗菌活性。与受试的其他氟喹诺酮类药物相比，加替沙星对MSSA、肺炎链球菌、溶血性链球菌、脆弱拟杆菌的作用明显优于环丙沙星和氧氟沙星，对肠杆菌科细菌和非发酵革兰阴性菌作用较环丙沙星略优或相仿。杀菌试验结果显示加替沙星具快速杀菌作用。除培养基的pH值改变对其抗菌活性略有影响外，细菌接种量及血清含量无明显影响。结论：加替沙星为一广谱抗菌药，抗菌作用强，对社区获得呼吸道感染病原菌抗菌活性尤高，提示该药治疗敏感菌所致感染可望有良好应用前景。     

头孢地尼和头孢克洛对523株呼吸道分离菌体外抗菌活性比较

目的：研究头孢地尼和头孢克洛对呼吸道常见分离菌的体外抗菌活性。方法：采用琼脂稀释法测定头孢地尼和头孢克洛对523株临床分离株的最低抑菌浓度(MIC)，E test法测定青霉素对肺炎球菌的MIC，用Nitrocefin测试细菌的β内酰胺酶，用纸片确证法检测大肠埃希菌和肺炎克雷伯菌的超广谱β内酰胺酶(ESBLs)，用WHONET5分析试验结果。结果：523株临床分离株对头孢地尼的敏感率范围为91．3％～100．0％，MIC50和MIC90范围分别为0．032～0．25mg／L和0．064～1mg／L，对头孢克洛的敏感率范围为82．6％～100．0％，MIC50，和MIC90范围分别为0．25～4mg／L和1～16mg／L。此外，30株青霉素中度敏感肺炎链球菌(PISP)对头孢地尼和头孢克洛的敏感率分别为66．7％和46．7％。产ESBLs的54株大肠埃希菌和51株肺炎克雷伯菌及8株青霉素耐药的肺炎链球菌(PRSP)对这2种头孢菌素的耐药率均为100％。结论：对青霉素敏感的肺炎链球菌、甲氧西林敏感的金黄色葡萄球菌、流感嗜血杆菌、卡他莫拉菌、β溶血链球菌，非产ESBLs的大肠埃希菌和肺炎克雷伯菌，头孢地尼比头孢克洛有较高的抗菌活性和较低的MIC值。对PISP头孢地尼比头孢克洛有较好的抗菌活性，产ESBLs的大肠埃希菌和肺炎克雷伯菌及PRSP，对两者均耐药。     

国产和进口替加环素体外抗菌活性比较

目的比较替加环素国产和进口制剂对常见临床分离菌的体外抗菌效果。方法标准肉汤稀释法测定国产与进口替加环素制剂对临床分离菌株最低抑菌浓度(MIC)。结果国产和进口替加环素制剂均具有广谱和强大体外抗菌活性。对于肠杆菌科细菌具有良好的体外抗菌作用,MIC90≤2 mg/L,其中对大肠埃希菌MIC90为0.25 mg/L;对碳青霉烯类敏感和耐药鲍曼不动杆菌的MIC90均分别为0.5 mg/L和2 mg/L;对金黄色葡萄球菌、表皮葡萄球菌、肠球菌属MIC90均为0.25 mg/L;对肺炎链球菌MIC90分别为0.25 mg/L和0.125 mg/L;对流感嗜血杆菌和卡他莫拉菌MIC90≤0.125 mg/L;对嗜麦芽窄食单胞菌抗菌活性稍差,MIC90为4 mg/L;2种制剂对各种细菌敏感率几乎相同,对各种细菌的累积抑菌曲线也几乎重叠。结论替加环素具有强大广谱体外抗菌活性,对各种耐药菌抗菌作用突出;进口与国产替加环素制剂体外抗菌效果相同。     

评估国产利奈唑胺对葡萄球菌和肠球菌体外抗菌活性

目的以进口利奈唑胺(原研药)为对照,评估国产利奈唑胺(仿制药)的体外抗菌活性及与进口利奈唑胺的一致性。方法收集6所医院分离的甲氧西林耐药和敏感金黄色葡萄球菌(MRSA、MSSA),甲氧西林耐药和敏感凝固酶阴性葡萄球菌(MRCNS、MSCNS),万古霉素耐药肠球菌(VRE)临床分离菌株,采用CLSI推荐的微量肉汤稀释法进行抗菌药物敏感性试验。结果国产利奈唑胺对金黄色葡萄球菌、凝固酶阴性葡萄球菌及VRE的MIC_(50)和MIC_(90)分别为2 mg/L和4mg/L、1 mg/L和2mg/L及2 mg/L和2mg/L,全部研究菌株对国产利奈唑胺呈现敏感。国产和进口利奈唑胺仅在对MSSA的MIC_(50)上相差一个稀释梯度,两者对其他葡萄球菌和VRE的MIC范围、MIC_(50)和MIC_(90)完全一致。国产和进口利奈唑胺对全部研究菌株抗菌药物敏感性结果的分类一致率(CA)和基本一致率(EA)均高达100%,两者对全部研究菌株的MIC值完全一致或相差不超过±1个稀释梯度。除了MRCNS对替考拉宁的敏感率为88.0%,葡萄球菌对替加环素、达托霉素、万古霉素和替考拉宁的敏感率均高达100%。VRE菌株对替加环素和达托霉素呈现100%敏感率,而对替考拉宁的敏感率仅为50.0%。相比之下,全部菌株对左氧氟沙星的敏感率明显低于其他抗菌药物。结论国产利奈唑胺对多重耐药葡萄球菌及肠球菌具有极好的体外抗菌活性,且与进口利奈唑胺的体外抗菌活性高度一致。     

头孢丙烯对5种儿童感染常见病原菌的抗菌活性

目的观察头孢丙烯等口服抗生素对5种儿童社区获得性感染常见致病菌的体外抗菌活性.方法选取近年北京儿童医院临床分离的金葡菌、化脓性链球菌、肺炎链球菌、流感嗜血杆菌和卡他莫拉菌菌株,采用E试验法检测其对头孢丙烯、头孢克洛、头孢地尼等抗生素的敏感性.结果头孢丙烯对所检测菌株的MIC90值分别是：甲氧西林敏感金葡菌0.75 mg/L;化脓性链球菌0.023 mg/L;肺炎链球菌青霉素敏感株0.094 mg/L,青霉素耐药株12 mg/L;β内酰胺酶阴性流感嗜血杆菌2mg/L,β内酰胺酶阳性16 mg/L;β内酰胺酶阴性卡他莫拉菌0.75 mg/L,β内酰胺酶阳性2 mg/L.PRSP株对头孢丙烯耐药率为61.9%,流感嗜血杆菌β内酰胺酶阳性株中占15.8%.结论头孢丙烯对金葡菌、化脓性链球菌、青霉素敏感肺炎链球菌、β内酰胺酶阴性卡他莫拉菌有良好抗菌作用;对β内酰胺酶阳性流感嗜血杆菌的抗菌活性低于头孢地尼;青霉素耐药肺炎链球菌株对头孢丙烯有较高的耐药率.     

2004-2005年住院患者细菌耐药监测研究

目的 监测和探讨我国不同地区的8所医院感染患者中分离细菌的耐药情况.方法 按照设计方案对7所医院从2004年9月1日至2005年8月31 日内分离的1 111株致病菌采用国际标准琼脂稀释法进行体外敏感试验,按照美国临床和实验室标准协会(CLSI)2007年的标准测定MIC,以MIC50和MIC90表示抗菌药物的抗菌活性,并计算出耐药率(R%)、中介率(I%)和敏感率(S%).结果 检测到的耐甲氧西林金黄色葡萄球菌(MRSA)和耐甲氧西林表皮葡萄球菌(MRSE)分别为39.3%和74.0%.未发现MRSA或MRSE对万古霉素耐药菌株.耐青霉素肺炎链球菌的总耐药率为33.3%(R%5.6%,1%27.7%).肠球菌91株,耐青霉素粪肠球菌40.8%,而耐青霉素屎肠球菌为100%.尚未发现对万古霉素耐药的肠球菌.分离到644株革兰阴性菌.最常见的细菌依次为;大肠埃希菌、肺炎克雷伯菌、不动杆菌、铜绿假单胞菌和阴沟肠杆菌.在大肠埃希菌和肺炎克雷伯菌中,产超广谱酶菌各占38.6%和26.7%.碳青霉烯类美罗培南、亚胺培南是所测定抗菌药物中对肠杆菌科细菌作用最强的抗牛素.多数革兰阴性杆菌对头孢哌酮/舒巴坦和头孢吡肟有很高敏感率.三代头孢中的头孢他啶对多数革兰阴性杆菌仍有很高敏感率.新喹诺酮类的莫西沙星、左氧沙星对革兰阳性和阴性菌均有很强的广谱抗菌作用.结论 本次监测(2004-2005年)与2002-2003年度监测结果显示,在致病菌的耐药类型和某些菌耐药增长趋势方面基本相似.     

头孢洛林-avibactam对含多种β内酰胺酶的革兰阴性菌和金葡菌的抗菌活性

头孢洛林是对革兰阳性菌和革兰阴性菌均有抗菌活性的新的广谱头孢菌素。本文报道头孢洛林联合β内酰胺酶抑制剂avibactam对含一种或多种β内酰胺酶的革兰阴性菌和甲氧西林敏感和耐药金葡菌的体外抗菌活性。431株1999—2008年临床分离菌,其中肠杆菌科细菌272株,包括99株携带多种β内酰胺酶,110株金葡菌中MSSA10株,     

Potency and spectrum reevaluation of cefdinir tested against pathogens causing skin and soft tissue infections: a sample of North American isolates

Cefdinir is a widely used orally administered cephalosporin for community-acquired respiratory tract infections and skin and soft tissue infections (SSTI). A total of 415 nonduplicate isolates of community-acquired SSTI (CA-SSTI) were collected from medical centers in North America and susceptibility tested against cefdinir and various compounds indicated for the treatment of CA-SSTI. The cefdinir MIC(50/90) in microg/mL/% susceptible for strains of the 7 principal CA-SSTI pathogens were: oxacillin-susceptible Staphylococcus aureus (0.5/0.5/100%), oxacillin-susceptible coagulase-negative staphylococci (0.06/0.12/100%), group A streptococci (< or =0.03/< or =0.03/100%), group B streptococci (< or =0.03/0.06/100%), viridans group streptococci (0.25/2/88%), Klebsiella spp. (0.12/1/95%), and Escherichia coli (0.25/0.5/95%). Cefdinir was the most potent oral cephalosporin tested against staphylococci and the Enterobacteriaceae species, and 8-fold to 64-fold more potent than cephalexin against these pathogens. Beta-Hemolytic streptococci was highly susceptible to cefdinir (MIC(90), < or =0.03-0.06 microg/mL), while viridans group streptococci showed slightly elevated MIC results. Cephalexin MIC values for streptococcal strains (MIC(90), 1-32 microg/mL) were 32-fold to 64-fold higher than those of cefdinir or other oral cephalosporins evaluated. Only 0.5% of all 415 recent CA-SSTI pathogens were resistant to cefdinir (MIC, > or = 4 mg/L). Cefdinir showed a spectrum and potency comparable or superior to other orally administered beta-lactams (cephalexin).     

In vitro evaluation of E1040, a new cephalosporin with potent antipseudomonal activity.

E1040 is a new parenteral cephalosporin with a broad antibacterial spectrum and potent antipseudomonal activity. The compound was four- to eightfold more active than ceftazidime and cefsulodin against Pseudomonas aeruginosa (MIC of E1040 for 90% of strains tested [MIC90], 3.13 micrograms/ml). E1040 also showed a potent activity against other glucose-nonfermentative rods, including Acinetobacter species. The activities of E1040 against most species of the family Enterobacteriaceae were roughly comparable to the activities of ceftazidime and cefmenoxime and exceeded that of cefotiam. Against Citrobacter freundii (MIC90, 0.78 micrograms/ml), Enterobacter cloacae (MIC90, 3.13 micrograms/ml), and Enterobacter aerogenes (MIC90, 0.2 micrograms/ml), E1040 was 16- to 256-fold more active than ceftazidime and cefmenoxime. The activities of E1040 against gram-positive cocci and anaerobes were comparable to those of ceftazidime, but the compound was less active than cefmenoxime. E1040 was at least as resistant as ceftazidime and cefmenoxime to hydrolysis by various beta-lactamases and showed high affinities for penicillin-binding protein 3 of both Escherichia coli and P. aeruginosa.     

In vitro evaluation of E1077, a new cephalosporin with a broad antibacterial spectrum.

E1077 is a novel parenteral cephalosporin with a wide spectrum of potent antibacterial activity against aerobic and anaerobic gram-positive and gram-negative bacteria. Against methicillin-susceptible Staphylococcus aureus, E1077 was twice as active as cefpirome, with an MIC for 90% of strains tested (MIC90) of 0.78 micrograms/ml. Methicillin-resistant S. aureus was moderately to highly resistant to E1077, but E1077 was at least twice as active as other beta-lactams tested. Against Enterococcus faecalis, E1077 was the most active of the cephalosporins tested (MIC90, 12.5 micrograms/ml) and was at least fourfold more active than cefpirome and ceftazidime. At concentrations of less than or equal to 0.78 micrograms/ml, E1077 inhibited 90% of streptococci and most of the members of the family Enterobacteriaceae tested, with the exceptions of Serratia marcescens and Proteus vulgaris, for which the MIC90s of E1077 were both 3.13 micrograms/ml. Against Pseudomonas aeruginosa, E1077 was two- to fourfold more active than cefpirome and ceftazidime. For the anaerobes, E1077 was as active against Bacteroides fragilis as was cefuzonam, and its activity was fourfold higher than those of cefpirome and ceftazidime. E1077 was at least as resistant as cefpirome to hydrolysis by various beta-lactamases, and these enzymes had a low affinity for E1077.     

In vitro activities of a dual-action antibacterial agent, Ro 23-9424, and comparative agents.

The in vitro activity of the dual-action antibacterial agent Ro 23-9424 was compared with those of cefotaxime, ceftazidime, ciprofloxacin, fleroxacin, imipenem, and amikacin against 358 aerobes and anaerobes. The MIC ranges, MICs for 50 and 90% of the strains (MIC50s and MIC90s), and percentage of strains susceptible for each agent at the recommended susceptible MIC breakpoint were determined for each genus. The MIC90s (micrograms per milliliter) of the agents against members of the family Enterobacteriaceae were as follows: ciprofloxacin, 0.063; Ro 23-9424, fleroxacin, and imipenem, 0.5; ceftazidime, 2; amikacin, 4; and cefotaxime, 16. The MIC90s (micrograms per milliliter) against Pseudomonas and Acinetobacter spp. were as follows: ciprofloxacin, 2; ceftazidime and imipenem, 8; Ro 23-9424, 16; fleroxacin, 32; amikacin, 64; and cefotaxime, 128. Against gram-positive bacteria, excluding the enterococci, the MIC90s (micrograms per milliliter) were as follows: ciprofloxacin, 1; imipenem, 4; Ro 23-9424 and fleroxacin, 8; amikacin, 64; and ceftazidime and cefotaxime, greater than 128. Against gram-positive bacteria, including the enterococci, the MIC90s changed only for the following agents: Ro 23-9424, 16 micrograms/ml; and amikacin, 128 micrograms/ml. Strains of Branhamella catarrhalis, Haemophilus influenzae, and Neisseria gonorrhoeae were 100% susceptible to Ro 23-9424, cefotaxime, ciprofloxacin, and fleroxacin, while the other three agents showed somewhat less activity only against N. gonorrhoeae. Against anaerobes, imipenem was the most effective agent, while the activities of the other six agents were variable.     

Argentinean collaborative multicenter study on the in vitro comparative activity of piperacillin-tazobactam against selected bacterial isolates recovered from hospitalized patients

The in vitro activity of piperacillin-tazobactam and several antibacterial drugs commonly used in Argentinean hospitals for the treatment of severe infections was determined against selected but consecutively isolated strains from clinical specimens recovered from hospitalized patients at 17 different hospitals from 9 Argentinean cities from different geographic areas during the period November 2001-March 2002. Out of 418 Enterobacteriaceae included in the Study 84% were susceptible to piperacillin-tazobactam. ESBLs putative producers were isolated at an extremely high rate since among those isolates obtained from patients with hospital acquired infections 56% of Klebsiella pneumoniae, 32% of Proteus mirabilis and 25% Escherichia coli were phenotypically considered as ESBLs producers Notably P.mirabilis is not considered by for screening for ESBL producers. ESBLs producers were 100% susceptible to imipenem and 70% were susceptible to piperacillin-tazobactam whereas more than 50% were resistant to levofloxacin. The isolates considered as amp C beta lactamase putative producers showed 99% susceptibility to carbapenems while 26.7% were resistant to piperacillin-tazobactam and 38.4% to levofloxacin. Noteworthy only 4% of the Enterobacteriaceae isolates were resistant to amikacin. Piperacillin-tazobactam was the most active agent against Pseudomonas aeruginosa isolates (MIC(90): 128 microg/ml; 78% susceptibility) but showed poor activity against Acinetobacter spp (MIC(90):>256 microg/ml; 21.7% susceptibility). Only 41.7% Acinetobacter spp isolates were susceptible to ampicillin-sulbactam. Piperacillin-tazobactam inhibited 100% of Haemophilus influenzae isolates (MIC(90) < 0.25 microg/ml) but only 16.6% of them were ampicillin resistant. The activity of piperacillin-tazobactam against oxacillin susceptible Staphylococcus aureus or coagulase negative staphylococci was excellent (MIC(90) 2 microg/ml; 100% susceptibility). Out of 150 enterococci 12 isolates (8%) were identified as E.faecium and only three isolates (2%), 2 E.faecium and 1 E.faecalis were vancomycin resistant. All the enterococci isolates were susceptible to linezolid. Piperacillin-tazobactam showed excellent activity (MIC(90) 2 microg/ml; 92% susceptibility). Regarding pneumococci all the isolates showed MICs of 16 microg/ml for piperacillin-tazobactam. Among 34 viridans group streptococci only 67% were penicillin susceptible and 85.2% ceftriaxone susceptible whereas piperacillin-tazobactam was very active (MIC(90) 4 microg/ml).Piperacillin-tazobactam is therefore a very interesting antibacterial drug to be used, preferably in combination (IE: amikacin-vancomycin) for the empiric treatment of severe infections occurring in hospitalized patients in Argentina. Caution must be taken for infections due to ESBL producers considering that the inoculum effect MICs can affect MIC values.     

In-vitro and in-vivo antibacterial activities of E1040, a new cephalosporin with potent antipseudomonal activity

E1040 is a new parenteral cephalosporin with a broad antibacterial spectrum and potent activity against Gram-negative bacteria including Pseudomonas aeruginosa. The in-vitro activities of E1040 against clinical isolates of Enterobacter cloacae, Ent. aerogenes, Providencia rettgeri, and Morganella morganii were superior to those of ceftazidime, cefoperazone, cefmenoxime, and cefuzonam. The activities of E1040 against Gram-positive cocci were comparable with those of ceftazidime, but it was less active than cefmenoxime, cefuzonam, and cefoperazone. Against Ps. aeruginosa, E1040 was more potent than the other compounds, with an MIC90 of 0.39 mg/l, 1/16 that of ceftazidime. The in-vitro activity of E1040 was well sustained in vivo as shown by results obtained in experimental infections in mice. In particular, E1040 was the most active drug against Ps. aeruginosa including gentamicin-resistant and beta-lactamase-overproducing strains. Morphological studies using a scanning electron microscope and a phase-contrast microscope showed that E1040 caused spheroplast and bulge formation in Ps. aeruginosa at low concentrations.     

In vitro and in vivo antibacterial activities of E1077, a novel parenteral cephalosporin.

E1077, a new injectable cephalosporin with a broad antibacterial spectrum and potent antibacterial activity, was evaluated for its in vitro and in vivo antibacterial activities in comparison with those of cefpirome, cefuzonam, ceftazidime, and cefotaxime. E1077 showed broad in vitro antibacterial activity against gram-positive and gram-negative bacteria. Against methicillin-susceptible Staphylococcus aureus, E1077 was as active as cefpirome; the MIC for 90% of strains tested (MIC90) was 1.0 microgram/ml. Against methicillin-resistant S. aureus, E1077 was less active (MIC90, 64 micrograms/ml). For Enterobacter cloacae and Pseudomonas aeruginosa, E1077 was fourfold more active than cefpirome, with MIC90s of 1.0 and 16 micrograms/ml, respectively. For Proteus vulgaris, the MIC90 of E1077 was 32 micrograms/ml, which was fourfold greater than that of cefpirome. Against other gram-negative strains tested, the in vitro activity of E1077 was comparable to that of cefpirome. The broad antibacterial spectrum of E1077 was reflected by its in vivo efficacy against experimental septicemia caused by gram-positive and gram-negative bacteria. Against S. aureus 90 and P. aeruginosa E7, E1077 had activity superior to those of the reference compounds; against most other bacterial strains, the efficacy of E1077 was similar to that of cefpirome. Levels of E1077 in plasma and tissue of mice were studied. At 15 min after a single subcutaneous administration, E1077 displayed high peak levels (mean, 31.8 +/- 3.1 micrograms/ml). These results indicate that the in vitro and in vivo efficacies of E1077 are similar to those of cefpirome except against P. aeruginosa and P. vulgaris.     

In vitro activity of linezolid against clinical isolates of Fusobacterium spp

OBJECTIVES: Although most susceptibility studies for linezolid have investigated aerobic bacteria, only a few have investigated anaerobe isolates. The aim of the present study was to determine the antibacterial activity of linezolid against a larger sample of clinical isolates of Fusobacterium spp. and to report on the detailed susceptibility, stratified by species. METHODS: The in vitro susceptibility of 80 clinical isolates of Fusobacterium (Fusobacterium necrophorum, n = 34; Fusobacterium nucleatum, n = 20; Fusobacterium varium, n = 18; Fusobacterium mortiferum; n = 8) was tested and compared with the activity of the older compounds amoxicillin and amoxicillin/clavulanic acid. RESULTS: The MIC of linezolid ranged from 0.016 to 1.0 mg/L, with the MIC(90) being 0.5 mg/L. The highest MIC obtained for linezolid (1.0 mg/L) was measured for an F. varium isolate. The MIC(90) for both, amoxicillin (range: 0.016-0.75 mg/L) and amoxicillin/clavulanic acid (range: 0.047-0.75 mg/L), was 0.5 mg/L. Overall, no resistant strains were found in the study. CONCLUSIONS: Compared with amoxicillin and amoxicillin/clavulanic acid, linezolid was less active against F. necrophorum (MIC(90) 0.25 mg/L) and F. nucleatum (MIC(90) 0.25 mg/L), equally active against F. varium (MIC(90) 0.75 mg/L) and slightly more active against F. mortiferum (MIC(90) 0.19 mg/L).     

In vitro and in vivo antibacterial activities of BO-1341, a new antipseudomonal cephalosporin.

BO-1341, a new antipseudomonal semisynthetic cephalosporin, was evaluated for in vitro and in vivo antibacterial activities in comparison with ceftazidime, cefotaxime, and cefoperazone. The in vitro activity of BO-1341 was generally superior or comparable to the activities of the reference antibiotics against clinical isolates of the family Enterobacteriaceae. BO-1341 was highly active against Pseudomonas aeruginosa (MIC for 90% of the strains tested, 1.56 micrograms/ml), Pseudomonas maltophilia (MIC for 50% of the strains tested, 1.56 micrograms/ml), and Acinetobacter calcoaceticus (MIC for 90% of the strains tested, 3.13 micrograms/ml). Furthermore, BO-1341 was highly active against P. aeruginosa isolates resistant to the other antibiotics. Of 199 P. aeruginosa isolates tested, only 2 were resistant to BO-1341. These two strains were also resistant to ceftazidime, cefotaxime, and cefoperazone. Haemophilus influenzae, Branhamella catarrhalis, and nonenteric streptococci were also susceptible to BO-1341, but Staphylococcus aureus, Streptococcus faecalis, and Bacteroides fragilis were not susceptible to the compound. The protective efficacy against experimental infections in mice caused by nine strains of gram-negative bacteria, including P. aeruginosa, reflected the potent in vitro activity.