联合用药后凝固酶阴性葡萄球菌体外抗菌活性分析

目的了解常用抗菌药物及联合药物对医院内感染凝固酶阴性葡萄球菌(CNS)的体外抗菌活性。方法常规方法培养细菌,用VITEK全自动微生物分析仪鉴定到种。MIC测定采用琼脂干板稀释方法,按照CLSI规定的标准进行。结果50株凝固酶阴性葡萄球菌对万古霉素、左氧氟沙星、阿米卡星、头孢脞啉的MIC90分别为2.0、16.0、8.0、64.0mg/L。万古霉素与左氧氟沙星、阿米卡星、头孢唑啉联合用药的MIC90分别为2.0、1.0、1.0mg/L,左氧氟沙星与阿米卡星、头孢唑啉联合用药的MIC90为2.0、8.0mg/L。结论医院内感染凝固酶阴性葡萄球菌的发生率及耐药性已越来越高,临床应根据病原菌感染的种类和细菌实验室药敏结果,结合临床经验用药的药物疗效正确使用抗菌药物。     

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。     

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.     

头孢地尼对临床分离菌的体外抗菌活性

目的:测定头孢地尼体外抗菌活性并与其他抗菌药比较。方法:采用琼脂稀释法测定抗生素最低抑菌浓度(MIC)。结果:651株细菌测定结果表明,头孢地尼对甲氧西林敏感金黄色葡萄球菌、表皮葡萄球菌(MSSA、MSSE)抗菌作用与头孢唑林、头孢呋辛相似,较头孢他啶强;对 MSSA、MSSE的 MIC90分别为 1、0.5 mg/L,细菌敏感率分别为 97%、100%。耐甲氧西林金黄色葡萄球菌、表皮葡萄球菌(MRSA、MRSE)、肠球菌对本药耐药,MIC90分别为＞128mg/L、8mg/L、＞128mg/L。头孢地尼对革兰阴性菌抗菌活性与头孢他啶相似,对大肠埃希菌、肺炎克雷伯菌、伤寒杆菌、痢疾杆菌、奇异变形杆菌MIC90分别为 2、4、1、0.25与 2 mg/L,敏感率分别为 85%、88%、100%、100%、88%,对部分细菌抗菌活性较阿米卡星、左氧氟沙星、司帕沙星强。聚团肠杆菌、阴沟肠杆菌、粘质沙雷菌、醋酸钙不动杆菌、铜绿假单胞菌对本药耐药,MIC90均＞128 mg/L。结论:头孢地尼对甲氧西林敏感葡萄球菌属、常见肠杆菌科细菌具强大的抗菌作用。     

利奈唑胺对革兰阳性球菌的体外抗菌活性研究

目的 检测利奈唑胺对临床分离的金黄色葡萄球菌、表皮葡萄球菌、溶血葡萄球菌、粪肠球菌、屎肠球菌等革兰阳性球菌的体外扰菌活性.为临床合理使用抗生素提供依据.方法 采用VITEK-32全自动微生物分析仪和ATB自动微生物分析仪鉴定和药敏系统对临床分离的常见革兰阳性球菌267株进行鉴定和药敏试验.根据其药敏结果 比较8种抗菌药物对葡萄球菌、肠球菌的抗菌活性.结果 在临床分离的267株菌中金黄色葡萄球菌111株,MRSA 74株(占66.7%).凝同酶阴性葡萄球菌96株(表皮葡萄球菌57株、溶血葡萄球菌39株),MRCNS有80株(占86.0%),粪肠球菌45株,屎肠球菌13株.利奈唑胺对207株葡萄球菌、58株肠球菌体外抗菌活性分别为100%、93.1%,与万古霉素相当,明显高于其他常用的抗生索(如红霉素、头孢唑林、环丙沙星等).其对金黄色葡萄球菌、凝同酶阴性葡萄球菌、肠球菌的MIC50和MIC90分别为1,1mg/L;1,1mg/L;2,4mg/L.结论 耐甲氧西林葡萄球菌发生率高,多重耐药严重,利奈唑胺对葡萄球菌的抗菌活性与万占霉索相当,对肠球菌也有较强的抗菌活性.葡萄球菌、肠球菌对左氧氟沙星、四环素、红霉素均产生了不同程度的耐药性.     

利福昔明——新一代非氨基糖甙类肠道抗生素

利福昔明系利福霉素衍生物，是第一个非氨基糖甙类肠道抗生素。通过作用于细菌中依赖DNAβ-亚单位的RNA多聚酶而抑制RNA合成，产生抗菌作用。对革兰阳性菌中的葡萄球菌、链球菌、革兰阴性大肠杆菌、沙门菌属、志贺菌属、小肠耶尔森菌等具有高度活性。     

利奈唑胺对革兰阳性球菌的体外抗菌活性研究

目的检测利奈唑胺对临床分离的金黄色葡萄球菌、表皮葡萄球菌、溶血葡萄球菌、粪肠球菌、屎肠球菌等革兰阳性球菌的体外抗菌活性,为临床合理使用抗生素提供依据。方法采用VITEK-32全自动微生物分析仪和ATB自动微生物分析仪鉴定和药敏系统对临床分离的常见革兰阳性球菌267株进行鉴定和药敏试验．根据其药敏结果比较8种抗菌药物对葡萄球菌、肠球菌的抗菌活性。结果在临床分离的267株菌中金黄色葡萄球闺111株,MRSA74株（占66．7％）,凝同酶阴性葡萄球菌96株（表皮葡萄球菌57株、溶血葡萄球菌39株）,MRCNS有80株（占86．0％）,粪肠球菌45株、屎肠球菌13株。利奈唑胺对207株葡萄球菌、58株肠球菌体外抗菌活性分别为100％,93．1％,与万古霉素相当,明显高于其他常用的抗生素（如红霉素、头孢唑林、环丙沙星等）。其对金黄色葡萄球菌、凝固酶阴性葡萄球菌、肠球菌的MIC50和MIC90分别为1．1mg／L;1.1mg／L：2.4mg／L。结论耐甲氧西林葡萄球菌发生率高,多重耐药严重,利奈唑胺对葡萄球菌的抗菌活性与万古霉素相当．对肠球菌也有较强的抗菌活性。葡萄球菌、肠球菌对左氧氟沙星、四环素、红霉素均产生了不同程度的耐药性。     

乳酸左氧氟沙星体外抗菌活性的研究

[目的]研究乳酸左氧氟沙星的体外抗菌活性。[方法]采用两倍稀释法对临床分离8种细菌进行体外抗菌试验。[结果]该药对金黄色葡萄球菌，肺炎球菌甚为敏感，其MIC50为0．05mg／L，MIC50为0．20mg／L，MBC50为0．05mg／L，MBC90为0．39mg／L结论：乳酸左氧氟沙星比氧氟沙星的抗菌活性强。     

新型氟喹诺酮类抗菌药物对成都地区临床分离菌株的体外抗菌活性研究

目的：研究5种氟喹诺酮类抗菌药物(FQNS)对2001--2003年成都地区3家教学医院分离的266株菌的体外抗菌活性。方法：采用琼脂二倍稀释法测定了环丙沙星、氧氟沙星、左氧氟沙星、司帕沙星和加替沙星对266株分离菌的最低抑菌浓度。结果：加替沙星和司帕沙星对266株临床分离菌的MIC50和MIC50均为0．25和8mg/L，低于环丙沙星(0．5和16mg／L)、氧氟沙星(2和16mg／L)、左氧氟沙星(0．5和8mg／L)。5种FONS对葡萄球菌具有很好的抗菌活性，对肺炎链球菌全部敏感，且新型FQNS的MIC50和MIC90是传统FQNS的1／4--1／16，但是FQNS对肠球菌的抗菌作用不理想。5种FQNS对流感嗜血杆菌具很好的抗菌活性；对大肠埃希菌、克雷伯菌属、枸橼酸杆菌属具有较强的抗菌活性，且新型FQNS略优于或相似传统FQNS；但是FQNS对肠杆菌属的抗菌作用不理想，新型FQNS优于传统FQNS，产气肠杆菌比阴沟肠杆菌敏感得多；而变形杆菌和沙雷菌属耐药率高。对于非发酵菌中铜绿假单胞菌新型FQNS和传统FQNS相似，而对不动杆菌属和嗜麦芽窄食单胞菌的MIC50和MIC90是传统FQNS的1／8。结论：加替沙星和司帕沙星等新型FQNS对于革兰阳性菌和革兰阴性菌都具有很强的体外抗菌活性，对革兰阳性菌的体外抗菌活性略优于革兰阴性菌。对临床上耐药性较高的枸椽酸杆菌属、铜绿假单胞菌、不动杆菌属和嗜麦芽窄食单胞菌都显示出很好的抗菌活性。     

替加环素对414株需氧革兰阴性和革兰阳性临床分离菌株的体外抗菌活性

目的测定替加环素等15种抗菌药物对我院2004年和2005年临床分离的414株革兰阴性菌和革兰阳性需氧菌的体外抗菌活性。方法采用微量肉汤稀释法测定替加环素等15种抗菌药物对所测菌株的MIC,数据分析采用WHONET5.3软件。结果MRSA对替加环素、利奈唑胺及万古霉素的敏感率均为100%,替加环素对MRSA的MIC90是所测抗菌药物中最低者;万古霉素耐药肠球菌(VRE)对替加环素及利奈唑胺敏感率均为100%,替加环素对所有肠球菌的MIC90分别是利奈唑胺和万古霉素的MIC90的1/8和1/16;替加环素对青霉素中介肺炎链球菌(PISP)的MIC90为0.5mg/L,对青霉素耐药肺炎链球菌(PRSP)的MIC范围是0.25~1mg/L,其他抗菌药物对PISP和PRSP的MIC90是替加环素的1~32倍;替加环素对亚胺培南耐药的鲍曼不动杆菌的MIC范围是其他抗菌药物的1/2~1/64;对铜绿假单胞菌的MIC90是32mg/L;产ESBLs大肠埃希菌和肺炎克雷伯菌对替加环素、美罗培南和亚胺培南敏感率均为100%。结论替加环素对铜绿假单胞菌的抗菌活性较差,对其他需氧革兰阴性杆菌有较好的体外抗菌活性;对需氧革兰阳性球菌的抗菌活性最强。     

Antipneumococcal activity of MEN 10700, a new penem, compared with other compounds, by MIC and time-kill kinetics.

The antipneumococcal activity of MEN 10700 was compared with those of nine other compounds by MIC and time-kill kinetics. MIC90s (mg/L) of 202 penicillin-susceptible, -intermediate and -resistant pneumococci were: 0.06, 1.0 and 2.0 (MEN 10700); 0.06, 0.5-1.0 and 2.0 (amoxycillin +/- clavulanate); 0.06, 0.5 and 4.0 (cefotaxime); 0.125, 0.5 and 2.0 (cefepime); 0.016, 0.125 and 0.25 (imipenem); 0.03, 0.5 and 1.0 (meropenem); 2.0 (ciprofloxacin); 0.125, >64.0 and >64.0 (clarithromycin); and 0.5 (vancomycin). Time-kill kinetics showed that MEN 10700, at 4 x MIC, was bactericidal for all 12 isolates tested at 4 x MIC. Kinetics of other beta-lactams were similar to those of MEN 10700, relative to MICs. Ciprofloxacin, at 4 x MIC, was uniformly bactericidal after 24 h. Clarithromycin exhibited slow kill kinetics, after 24 h. Vancomycin was bactericidal against 11/12 isolates at 2 x MIC after 24 h.     

Effect of human plasma on the antimicrobial activity of iclaprim in vitro

OBJECTIVES: Iclaprim is a novel diaminopyrimidine for which a human plasma binding level of approximately 93% has been reported. The purpose of this study was to evaluate the effect of human plasma on the in vitro activity of iclaprim and to compare it with that of fusidic acid, teicoplanin and vancomycin, antibiotics with protein binding to human plasma of 97%, >90% and 55%, respectively. METHODS: MICs were determined using 40 methicillin-susceptible Staphylococcus aureus (MSSA) and 38 methicillin-resistant S. aureus (MRSA) isolates in Mueller-Hinton broth (MHB) alone or in the presence of 50% human plasma. RESULTS: MICs of iclaprim were not affected by the addition of human plasma. MIC ranges (MIC(90)) for iclaprim against MSSA and MRSA were < or =0.016-0.06 mg/L (MIC(90) 0.06 mg/L) and < or =0.016-0.5 mg/L (MIC(90) 0.06 mg/L), respectively, in MHB and < or =0.016-0.125 mg/L (MIC(90) 0.06 mg/L) and < or =0.016-0.25 mg/L (MIC(90) 0.125 mg/L), respectively, in the presence of human plasma. As expected, the antimicrobial activity of fusidic acid was greatly affected by the presence of human plasma (MIC elevations of 4- to >128-fold), whereas MICs of vancomycin remained unchanged. By contrast, despite the high protein binding, MICs of teicoplanin were only marginally affected by the presence of plasma with an MIC elevation of maximum 8-fold for two strains. CONCLUSIONS: This study demonstrates that human plasma does not affect the MIC of iclaprim in vitro.     

In vitro activity of sparfloxacin and six reference antibiotics against gram-positive bacteria.

The in vitro activity of sparfloxacin, a new fluoroquinolone, was assessed against 234 gram-positive bacterial isolates by agar dilution (10(4) CFU/spot). Sparfloxacin activity was compared with that of ciprofloxacin and five other antibiotics. Sparfloxacin was the most active drug tested against methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococci (MIC90, 0.125-0.25 mg/l). Sparfloxacin was also the most active drug tested against Enterococcus faecalis (MIC90, 1 mg/l) and showed equal activity against gentamicin-susceptible and gentamicin-resistant (MIC greater than 2,000 mg/l) enterococci. Sparfloxacin was the most active quinolone tested against Streptococcus pneumoniae and S. pyogenes (MIC90, 1 mg/l). Most Corynebacterium jeikeium showed exquisite susceptibility to sparfloxacin (MIC, 0.06-0.25 mg/l). For MRSA, time-kill curves showed sparfloxacin to be rapidly bactericidal at the MIC of the organism. Sparfloxacin showed greater and more sustained bactericidal activity than ciprofloxacin and vancomycin at 1x and 2x the MIC. Reduction in the activity of sparfloxacin occurred with decreased agar pH (from 7.0 to 6.0) and increased bacterial inoculum. Sparfloxacin showed superior activity compared to reference drugs against most gram-positive bacteria.     

Antipneumococcal activity of ABT-773 compared to those of 10 other agents

MICs, time-kills, and postantibiotic effects (PAEs) of ABT-773 (a new ketolide) and 10 other agents were determined against 226 pneumococci. Against 78 ermB- and 44 mefE-containing strains, ABT-773 MICs at which 50% of the isolates tested were inhibited (MIC(50)s) and MIC(90)s were 0.016 to 0.03 and 0.125 microgram/ml, respectively. Clindamycin was active only against macrolide-resistant strains containing mefE (MIC(50), 0.06 microgram/ml; MIC(90), 0.125 microgram/ml). Activities of pristinamycin (MIC(90), 0.5 microgram/ml) and vancomycin (MIC(90), 0.25 microgram/ml) were unaffected by macrolide or penicillin resistance, while beta-lactam MICs rose with those of penicillin G. Against 19 strains with L4 ribosomal protein mutations and two strains with mutations in domain V of 23S rRNA, ABT-773 MICs were 0.03 to 0.25 microgram/ml, while macrolide and azalide MICs were all >/=16.0 microgram/ml. ABT-773 was bactericidal at twice the MIC after 24 h for 8 of 12 strains (including three strains with erythromycin MICs greater than or equal to 64.0 microgram/ml). Kill kinetics of erythromycin, azithromycin, clarithromycin, and roxithromycin against macrolide-susceptible strains were slower than those of ABT-773. ABT-773 had longer PAEs than macrolides, azithromycin, clindamycin, or beta-lactams, including against ermB-containing strains. ABT-773, therefore, shows promising in vitro activity against macrolide-susceptible as well as -resistant pneumococci.     

Activity of the new quinolones WCK 771, WCK 1152 and WCK 1153 against clinical isolates of Streptococcus pneumoniae and Streptococcus pyogenes

Objectives and methods: The new fluoroquinolones WCK 771, WCK 1152 and WCK 1153 were developed to overcome quinolone resistance in Gram-positive bacteria. The activity of these new quinolones was tested against 159 clinical isolates of Streptococcus pneumoniae and 52 clinical isolates of Streptococcus pyogenes using the microbroth dilution method. RESULTS: MIC50/MIC90 values (mg/L) of WCK 771, WCK 1152 and WCK 1153 for quinolone-susceptible S. pneumoniae (n = 119; 54 penicillin G-susceptible, 53 penicillin G-intermediate, and 12 penicillin G-resistant strains) were 0.25/0.5, 0.03/0.06 and 0.016/0.03, respectively. MIC50/MIC90 values (mg/L) for quinolone-resistant pneumococci (n = 40) increased to 4/16, 0.25/1 and 0.125/0.5, respectively. Against S. pyogenes, WCK 771, WCK 1152 and WCK 1153 were also highly active with MIC50/MIC90 values (mg/L) of 0.25/0.25, 0.03/0.06 and 0.03/0.03, respectively. CONCLUSIONS: Overall, WCK 771 was highly active against quinolone-susceptible, but not against quinolone-resistant S. pneumoniae, whereas WCK 1152 and WCK 1153 were more potent and were able to overcome quinolone resistance in both S. pneumoniae and S. pyogenes.     

Anti-anaerobic activity of AZD2563, a new oxazolidinone,compared with eight other agents

The anti-anaerobic activity of AZD2563, a new oxazolidinone, was compared with that of eight other agents against 201 Gram-positive and 99 Gram-negative anaerobes. MIC(50) and MIC(90) values (mg/L) for the 201 Gram-positive organisms were as follows: AZD2563, 1.0/4.0; linezolid, 1.0/4.0; quinupristin/dalfopristin, 0.5/1.0; amoxicillin, 0.25/1.0; clindamycin, 0.25/8.0; metronidazole, 0.5/>16.0; vancomycin, 0.5/2.0; teicoplanin, 0.125/0.25; and meropenem, 0.06/1.0. AZD2563, linezolid, vancomycin, teicoplanin and quinupristin/dalfopristin were mainly active against Gram-positive anaerobes, with no useful activity against Gram-negative anaerobes.     

In vitro and in vivo activities of a new quinolone, WIN 57273, possessing potent activity against gram-positive bacteria.

The antibacterial activity of a new 7-dimethylpyridinyl quinolone, WIN 57273, was assessed by using in vitro and in vivo models. Agar inclusion and broth dilution in vitro tests revealed broad-spectrum activity against gram-positive and selected gram-negative organisms, with the greatest potency observed against the staphylococci. The MIC for 90% of coagulase-positive strains tested (MIC90) was less than or equal to 0.002 micrograms/ml; for the coagulase-negative strains the MIC90 was 0.008 micrograms/ml. Against enterococci the MIC90 was 0.06 micrograms/ml, with comparable activity observed against group A and group B streptococci as well as against the pneumococci. In general, the MIC90s for the gram-negative bacteria were less than or equal to 1 micrograms/ml. Exceptions were Serratia marcescens (MIC90, 16 micrograms/ml), Citrobacter freundii (MIC90, 4 micrograms/ml), and Pseudomonas aeruginosa (MIC90, 8 micrograms/ml). The greatest potency was observed against Haemophilus spp. and Neisseria spp., with MIC90s of 0.06 and 0.016 micrograms/ml, respectively. Broad-spectrum activity was also observed against anaerobes, with MIC90s ranging from 0.125 to 0.5 micrograms/ml among the species tested. The in vivo efficacy was determined by using a murine model by calculating the 50% protective doses against a lethal bacterial infection caused by strains of Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Streptococcus pyogenes, Listeria monocytogenes, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The staphylocci were most susceptible, with 50% protective doses for all strains ranging from 0.1 to 0.7 mg/kg. With the exception of the Pseudomonas infection, which was refractory to treatment, animals that were part of the other infection models responded to less than 10 mg/kg. Equivalent activity was seen with the subcutaneous or the oral route of drug administration. WIN 57273 was significantly more potent than ciprofloxacin in treating gram-positive bacterial infections (2- to 20-fold) but was significantly less effective at treating gram-negative bacterial infections (30- to 300-fold).     

Antimicrobial activity of tigecycline against recent isolates of respiratory pathogens from Asian countries

In vitro activities of tigecycline were compared with 15 other comparator agents against recent clinical isolates of respiratory pathogens (623 Streptococcus pneumoniae, 105 Staphylococcus aureus, 92 Klebsiella pneumoniae, and 84 Haemophilus influenzae isolates) collected from 11 Asian countries. All isolates of S. pneumoniae from Asian countries were susceptible to tigecycline regardless of penicillin susceptibility with MIC90 of 相似文献   

In vitro activity of tigecycline against extended-spectrum β-lactamase-producing Enterobacteriaceae and MRSA clinical isolates from Mexico: a multicentric study

Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae and methicillin resistant Staphylococcus aureus (MRSA) are important nosocomial pathogens. This study reports the in vitro activity of tigecycline against 573 and 482 ESBL-producing Enterobacteriaceae and MRSA isolates, respectively. More than 94% of all tested isolates were susceptible to tigecycline; MIC(90) found was 0.25 to 2 mg/L for ESBL-producing Enterobacteriaceae and was 0.125 mg/L for MRSA. Tigecycline demonstrated excellent in vitro activity against a wide spectrum of nosocomial pathogens.     

Comparative antianaerobic activities of the ketolides HMR 3647 (RU 66647) and HMR 3004 (RU 64004).

HMR 3647 (RU 66647) and HMR 3004 (RU 64004), two ketolides, had MICs at which 50% of the strains are inhibited (MIC50s) of 0.06 to 0.125 microg/ml and MIC90s of 16.0 microg/ml against 352 anaerobes. MIC50s and MIC90s of erythromycin, azithromycin, clarithromycin, and roxithromycin were 0.5 to 2.0 microg/ml and 32.0 to >64.0 microg/ml, respectively. HMR 3647 and HMR 3004 were more active against non-Bacteroides fragilis-group anaerobes (other than Fusobacterium mortiferum, Fusobacterium varium, and Clostridium difficile).