乙基西索米星与庆大霉素、妥布拉霉素和丁胺卡那霉素体外抗菌活性的比较

本文报道乙基西索米星对548株临床分离菌的体外抗菌作用,并与庆大霉素、妥布拉霉素和丁胺卡那霉素进行比较。丁胺卡那霉素对革蓝氏阴性杆菌的作用最强。乙基西索米星对金葡菌和其他革蓝氏阳性球菌(除肠球菌外)具良好抗菌作用,为四种氨基糖苷类抗生素中作用最强者。乙基西索米星对肠杆菌科细菌的作用与妥布拉霉素相似,但较庆大霉素强,为四者之中对绿脓杆菌的作用最差者。对庆大霉素、妥布拉和丁胺卡那霉素耐药的金葡菌中仍有40～86％的菌株对本品敏感,对庆大霉素和妥布拉霉素耐药的革蓝氏阴性杆菌中仍有30～46.8％的菌株对本品敏感。 鉴于临床致病菌对庆大霉素的耐药率逐渐增加,乙基西索米星对于国内临床上耐药革蓝氏阴性杆菌的作用及其机理值得进一步研究。     

氧哌嗪青霉素体外抗菌活性

以试管双倍稀释法测定氧哌嗪青霉素(PIPC)和羧苄青霉素(CBPC)对从84例烧伤病人创面分离到的118株革兰氏阴性杆菌的MIC和PIPC对46株粪链球菌、34株耐药性金黄色葡萄球菌的MIC。结果表明PIPC对粪链球菌和奇异变形杆菌的抗菌作用最为突出,在3.12μg/ml时分别可抑制100％和83％的菌株。在6.25μg/ml时抑制全部菌株。其次为产气杆菌和绿脓杆菌,在12.5μg/ml时分别抑制70％和63％的菌株。在PIPC临界药敏浓度(12.5μg/ml)不敏感的绿脓杆菌菌株,全部被≤100μg/ml抑制,而CBPC在100μg/ml和200μg/ml时分别抑制76％和79％的菌株。对大肠杆菌、枸橼酸杆菌和硝酸盐阴性杆菌,在12.5μg/ml时分别抑制45％、44％和40％的菌株。对耐药性金黄色葡萄球菌和肺炎克雷白氏菌,在12.5μg/ml时分别抑制32％和21％的菌株,抗菌作用较差。PIPC对7种革兰氏阴性杆菌的抗菌作用均较CBPC为优。在9株对庆大霉素(GM)耐药的绿脓杆菌中,6株对PIPC的MIC在6.25～12.5μg/ml间。PIPC和丁胺卡那霉素(AMK)联合,对12株绿脓杆菌有66.6％的菌株呈协同,而PIPC和GM联合未见协问。对8株枸橼酸杆菌,PIPC和AMK或GM联合均未见协同。最后就PIPC和AMK对绿脓杆菌的协同作用的机制进行了讨论。     

耐药革兰氏阴性杆菌中β-内酰胺酶的分类和分布研究

采用聚丙烯酰胺凝胶等电聚焦电泳法对上海地区临床常见对氨苄青霉素耐药革兰氏阴性杆菌(绿脓杆菌同时对羧苄青霉素耐药)中β-内酰胺酶的研究结果。用Nitrocefin法对150株革兰氏阴性杆菌进行酶定性检测,阳性率为88.7％(133/150)。对氨苄青霉素耐药率为67.3％(101/150)。33株对氨苄青霉素或羧苄青霉素敏感产酶株中的31株只产染色体介导的酶。90株耐药产酶株中只产染色体酶的占10％(9株),产质粒介导的酶占90％(81株),其中又以TEM-1酶的分布最广,存在于8种细菌中,其发生率为44.4％(40/90),其次为PSE-1酶,分布于7种细菌中,发生率为15.6％。 TEM-2、OXA-1和PSE-3酶分别为14.4％、12.2％和1.1％,而OXA-3和SHV-1酶较为少见,OXA-2酶则未检测到。     

哌拉西林/舒巴坦对临床分离菌的体外抗菌活性研究

目的　比较研究哌拉西林、舒巴坦、哌拉西林与舒巴坦不同比例联合及阿莫西林 /舒巴坦 (2∶1) ,对临床分离 3 0 9株需氧菌和 3 0株厌氧菌的体外抗菌活性及其影响因素 (研究哌拉西林 /舒巴坦 (2∶1)对金葡球菌、大肠埃希氏菌和铜绿假单胞菌的的杀菌曲线 )。方法　采用琼脂平板稀释法及肉汤稀释法测定MIC值 ,Nitrocefin纸片法测定细菌产生的 β 内酰胺酶 ,时间杀菌曲线采用肉汤 10倍稀释法。结果　对临床分离的3 3 9株需氧菌及厌氧菌体外抗菌活性研究结果显示 ,哌拉西林及其与舒巴坦联合时 ,对革兰氏阳性球菌及厌氧菌的体外抗菌活性MIC50 为 1～ 4μg/ml,MIC90 多数低于 12 8μg/ml,优于革兰氏阴性杆菌 ,其MIC50 为 1～12 8μg/ml ,MIC90 多数高于 12 8μg/ml;单用舒巴坦对各种细菌的体外抗菌活性极差 ,多数菌的MIC50 及MIC90 分别为 64及 2 5 6μg/ml。对革兰氏阴性杆菌及厌氧菌 ,哌拉西林与舒巴坦联合时体外抗菌活性明显优于单用哌拉西林 ;对于革兰氏阳性球菌 ,哌拉西林联合舒巴坦后体外抗菌活性改善不如革兰氏阴性杆菌及厌氧菌。哌拉西林对产酶株的MIC高于非产酶株 ,联合舒巴坦后 ,产酶株MIC降低而非产酶株MIC变化不明显。不同比例联合的体外抗菌活性比较发现 ,以哌拉西林 /舒巴坦 2∶1联合时效果较好。     

Micronomicin向胆囊组织及胆汁中转运的临床研究

Micronomicin(MCR)系日本协和发酵厂发现并研制的氨基糖苷类抗生素。它抗菌谱广,有强杀菌力,并有使绿脓杆菌、沙雷氏菌属产生的6′-乙酰转移酶不失活的特性,其耳毒性较庆大霉素(GM)、妥布拉霉素(TOB)、地贝卡星(DKB)、丁胺卡那霉素(AMK)为低,肾毒性较 GM、DKB 为小,而且 MCR 还具有其它氨基糖苷抗生素类不具     

氨基糖甙类抗生素的体外抗生素后效应研究

目的 观察氨基糖甙类抗生素庆大霉素(GN)、奈替米星(NTL)和阿米卡星(AMK)的体外抗生素后效应(PAE).方法 应用AVANTAG全能自动化微生物分析仪用光密度测定法测定GN、NTL和AMK对4种共20株受试菌的PAE.结果 3种氨基糖甙类抗生素对受试革兰氏阳性球菌和革兰氏阴性杆菌均产生明显的PAE,亚抑菌浓度(1/2MIC)时也存在PAE,PAE值随药物浓度的增加而增大(P<0.05),表现出强的浓度依赖性,不同菌株产生不同的PAE.结论 PAE的存在提示设计氨基糖甙类抗生素给药方案时可减少给药次数,延长用药间歇,维持药物疗效,从而减轻毒副作用.     

464株革兰氏阴性杆菌体外耐药性监测

目的 了解医院革兰氏阴性杆菌流行分布与耐药性。方法 采用细菌鉴定与药敏系统监测464株革兰氏阴性杆菌的耐药性。结果 464株革兰氏阴性杆菌中以铜绿假单胞菌(29.3％)和大肠杆菌(23.3％)最多见;革兰氏阴性杆菌耐药率最低的抗生素为亚胺培南(25.0％),其次为阿米卡星(49.6％)、庆大霉素(58.4％)、妥布霉素(53.9％)和环丙沙星(55.0％)。结论 临床医生应当高度重视细菌耐药问题,及时掌握病原菌的流行分布与敏感模式,合理使用抗生素。     

氨基糖甙类抗生素的体外抗生素后效应研究

目的 观察氩基糖甙类抗生素庆大霉素(GN)、奈替米星(NTL)和阿米卡星(AMK)的体外抗生素后效应(PAE)。方法 应用AVANTAG全能自动化微生物分析仪用光密度测定法测定GN、NTL和AMK对4种共20株受试菌的PAE。结果 3种氩基糖甙类抗生素对受试革兰氏阳性碡菌和革兰氏阴性杆菌均产生明显的PAE，亚抑菌浓度(1／2MIC）时也存在PAE，PAE值随药物浓度的增加而增大(P<0．05)，表现出强的浓度依赖性，不同菌株产生不同的PAE。结论 PAE的存在提示设计氯基糖甙类抗生素给药方案时可减少给药次数，延长用药间歇，维持药物疗效，从而减轻毒副作用。     

哌拉西林／舒巴坦对临床分离功的体外抗菌活性研究

目的比较研究哌拉西林、舒巴坦、哌拉西林与舒巴坦不同比例联合及阿莫西林/舒巴坦(21),对临床分离309株需氧菌和30株厌氧菌的体外抗菌活性及其影响因素(研究哌拉西林/舒巴坦(21)对金葡球菌、大肠埃希氏菌和铜绿假单胞菌的的杀菌曲线).方法采用琼脂平板稀释法及肉汤稀释法测定MIC值,Nitrocefin纸片法测定细菌产生的β-内酰胺酶,时间杀菌曲线采用肉汤10倍稀释法.结果对临床分离的339株需氧菌及厌氧菌体外抗菌活性研究结果显示,哌拉西林及其与舒巴坦联合时,对革兰氏阳性球菌及厌氧菌的体外抗菌活性MIC5o为1～4μg/ml,MIC90多数低于128μg/ml,优于革兰氏阴性杆菌,其MIC50为1～128μg/ml,MIC90多数高于128μg/ml;单用舒巴坦对各种细菌的体外抗菌活性极差,多数菌的MICso及MIC90分别为64及256μg/ml.对革兰氏阴性杆菌及厌氧菌,哌拉西林与舒巴坦联合时体外抗菌活性明显优于单用哌拉西林;对于革兰氏阳性球菌,哌拉西林联合舒巴坦后体外抗菌活性改善不如革兰氏阴性杆菌及厌氧菌.哌拉西林对产酶株的MIC高于非产酶株,联合舒巴坦后,产酶株MIC降低而非产酶株MIC变化不明显.不同比例联合的体外抗菌活性比较发现,以哌拉西林/舒巴坦21联合时效果较好.哌拉西林与舒巴坦21联合时,对多数临床分离菌的体外抗菌活性与阿莫西林/舒巴坦(21)的体外抗菌活性相当.本研究中,I临床分离细菌对哌拉西林的耐药率以假单胞菌属最高,达61.5%,其次是肠杆菌属细菌及大肠埃希氏菌,分别为50.8%、50.0%.哌拉西林联合舒巴坦后,所有细菌的耐药率明显下降.体外杀菌效果研究表明,当哌拉西林联合舒巴坦21时,4×MIC浓度作用于金葡球菌、大肠埃希氏菌及铜绿假单胞菌后,细菌数均随时间延长而呈指数级减少,在作用于8h细菌均被杀灭.1×MIC及2×MIC作用于以上细菌后,杀菌效果不及4×MIC.各种细菌的体外抗菌活性主要受培养基pH值及接种菌量的影响,几乎不受小牛血清白蛋白浓度的影响.结论哌拉西林/舒巴坦对β-内酰胺酶产生菌株的体外抗菌活性优于哌拉西林,以21联合效果最好,杀菌效果以4×MIC浓度最好,体外抗菌活性受培养基pH值及接种量的影响.     

我院耐碳青霉烯类抗菌药物革兰氏阴性杆菌的分离及其产金属β-内酰胺酶情况分析

目的:为我院临床合理应用抗菌药物提供参考。方法:对我院2013年5月-2015年12月住院患者感染革兰氏阴性杆菌的耐药及产金属β-内酰胺酶(MBLs)情况进行回顾性分析。结果:我院2013-2015年共检出革兰氏阴性杆菌2 089株,其中肠杆菌科细菌1 456株(69.70%)、非发酵菌633株(30.30%),以大肠埃希菌、铜绿假单胞菌、肺炎克雷伯菌、鲍曼不动杆菌和阴沟肠杆菌为主。共检出耐碳青霉烯类菌株406株(19.44%),包括非发酵菌367株、肠杆菌科细菌39株。耐碳青霉烯类菌株对16种抗菌药物的耐药率均大于50%,而非耐碳青霉烯类菌株的耐药率相对较低;除氨曲南外,耐碳青霉烯类菌株对其余15种抗菌药物的耐药率均显著高于非耐碳青霉烯类菌株,差异均有统计学意义(P<0.05)。共检出产MBLs耐药菌株36株(8.87%),包括产MBLs耐药铜绿假单胞菌13株、产MBLs耐药鲍曼不动杆菌23株;未检出产MBLs耐药肠杆菌科细菌。结论:我院革兰氏阴性杆菌以肠杆菌科细菌为主;耐碳青霉烯类菌株以非发酵菌为主,耐药率普遍高于非耐耐碳青霉烯类菌株;产MBLs情况较为严重,且产酶菌株均为非发酵菌。临床应加强病原菌耐药性及产酶菌株的监测,避免不合理应用抗菌药物而造成耐药菌株的产生与传播。     

Antibacterial activities and PK/PD parameters of aminoglycosides against recent clinical isolates of gram-negative rods

We examined antibacterial activities and PK/PD parameters of six kinds of aminoglycosides against seven bacterial species of clinical isolates in 2001. Aminoglycoseides examined were gentamicin (GM), dibekacin (DKB), tobramycin (TOB), amikacin (AMK), netilmicin (NTL), and isepamicin (ISP), and bacterial isolates used were each 50 strains of Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Citrobacter freundii, Proteus spp., Serratia marcescens and Pseudomonas aeruginosa. All aminoglycosides showed good activities with low MICs against 6 species of Enterobacteriacea except S. marcescens. Eight strains (3.2%) among them were resistant to one or more aminoglycosides. Resistance to multiple aminoglycosides were detected in 16 strains (32%) of S. marcescens, among which 13 strains were resistant to AMK but susceptible to ISP. Three (6%) strains of P. aeruginosa were resistant to multiple drugs, one of which was resistant to all six aminoglycosides, and others were moderately susceptible to AMK and ISP, and susceptible to GM, AMK and ISP. Using a ratio of peak serum concentration to MIC90 (Cmax/MIC90) or a ratio of area under the curve to MIC90 (AUC/MIC90) as a pharmacokinetic and pharmacodynamic (PK/PD) parameter, we estimated the efficacy of the drug. An excellent effect of ISP, which was injected intramuscularly or intravenously at a dose of 400 mg, was expected for strains of Enterobacteriacea except S. marcescens. The Cmax/MIC90 ratios for S. marcescens were comparably higher in GM and ISP and that for P. aeruginosa were rather high in TOB when compared to other aminoglycosides. Another PK/PD parameter, AUC/MIC90 ratio, was high enough in NTL and ISP for Enterobacteriacea, suggesting good efficacy of these drugs. The (AUC/MIC90) ratios for S. marcescens were comparably high in GM and ISP, and that for P. aeruginosa were high in TOB, DKB, and ISP.     

Antibacterial activities of various aminoglycosides against clinically isolated methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) were isolated from samples collected from various patients during 1986, and antibacterial activities of 6 aminoglycosides (AGs) (netilmicin (NTL), gentamicin (GM), sisomicin (SISO), dibekacin (DKB), tobramycin (TOB) and amikacin (AMK] and 4 beta-lactam antibiotics (cefazolin (CEZ), cefmetazole (CMZ), cloxacillin (MCIPC) and methicillin (DMPPC) against these MRSA were evaluated. Among these 6 AGs, NTL was the most potent, and its MIC50 and MIC80 were 1.56 and 3.13 micrograms/ml, respectively. Antibacterial activities of GM, SISO, DKB and TOB were weak, and MIC50's of GM and DKB were both 100 micrograms/ml, while those of SISO and TOB were 50 and greater than 100 micrograms/ml, respectively. Frequency of highly resistant specimens to AMK was rather low and its MIC50 and MIC80 were 12.5 and 25 micrograms/ml, respectively. As for antibacterial activities of the above 4 beta-lactam antibiotics, the MIC50 and MIC80 of CMZ were 6.25 and 12.5 micrograms/ml, respectively, and therefore, its antibacterial activity to MRSA is relatively good. However, MIC50's of CEZ, MCIPC and DMPPC were all greater than 100 micrograms/ml, showing poor antibacterial activities. Recently, MRSA became a problem in various fields of clinical practice, and a number of literatures reporting refractory infections caused by MRSA have been published. Since MRSA is featured as multiply resistant bacteria, it is known that MRSA is resistant to the majority of existing antibiotics (penicillins, cephems, macrolides, AGs, etc.). In 1985, we reported results of our study concerning the antibacterial activities of a number of CEPs and some of AGs against multiply resistant S. aureus including MRSA.(ABSTRACT TRUNCATED AT 250 WORDS)     

Bacteriological evaluation of netilmicin

The following results were obtained from the bacteriological evaluations of netilmicin (NTL), a newly developed antibiotic agent, with gentamicin (GM), dibekacin (DKB) and amikacin (AMK) as the controls. (1) NTL demonstrated broad antibacterial spectra against both Gram-positive and Gram-negative bacteria, but its antibacterial potency against streptococci was not very strong among other Gram-positive bacteria. (2) In terms of distribution of sensitivity of clinically isolated bacterial strains, NTL proved to have antibacterial potency comparable to that of GM and higher potency than that of DKB of AMK against E. coli K. pneumonia, Enterobacter sp., or H. influenzae. However, its efficacy was inferior to GM against Proteus sp., S. marcescens and P. aeruginosa. (3) In conjunction with the influences of pH of culture media or of addition of horse sera upon the antibacterial efficacy, NTL showed an inclination similar to that of GM, DKB and AKM. Its antibacterial efficacy was fortified on the alkaline side or by addition of sera. In connection with the influences of the amounts of inoculated bacteria upon antibacterial efficacy, there were hardly any appreciable influences on it by any of the tested bacterial strains. (4) The interactions of NTL with carbenicillin were evaluated with the chequerboard titration method to find remarkable cooperative actions in any of E. coli, K. pneumoniae, S. marcescens, A. calcoaceticus and P. aeruginosa. (5) The results of evaluation on the patterns of its antibacterial effects revealed that it acted bactericidal in any tested bacterial strains. (6) As to the therapeutic effects against experimental infections in mice, it was found out that NTL = GM greater than DKB and AMK against E. coli, GM greater than NTL = DKB and AMK against K. pneumoniae and GM and DKB greater than NTL greater than or equal to AMK against A. calcoaceticus and P. aeruginosa in the decreasing order of efficacy.     

The antimicrobial activity of sisomicin against fresh clinical isolates

Antimicrobial activities of sisomicin (SISO) against clinical isolates obtained in the second half of 1986 were investigated together with other 4 aminoglycosides (AGs) (gentamicin (GM), tobramycin (TOB), dibekacin (DKB), amikacin (AMK] and 2 cephems (cefotiam, cefotaxime), and were compared to the results reported in the period of late 1970's through early 1980's in Japan. 1. The incidence of SISO-resistant Staphylococcus aureus in the present study was 18% and is comparable to that of the other studies suggesting that the incidence of SISO resistant strains remains on the stable level. The incidence of SISO-resistant Pseudomonas aeruginosa showed the tendency of slight increase. 2. SISO-resistant strains of Enterobacter spp., Serratia marcescens and Citrobacter freundii did not show increase from the 1970/1980 levels. 3. Isolation rates of SISO-resistant indole(+) Proteus varied depending on strains. Isolation rates of SISO-resistant P. vulgaris and Morganella morganii were both as low as 4%, but that of Providencia rettgeri was as high as 60%. Refering to an American study reporting that the Genus Providencia including P. rettgeri showed high incidence of resistance to SISO as well as to GM or TOB, we pointed out that the antimicrobial activity of AGs against Genus Providencia should be evaluated separately from those of other indole(+) Proteus strains. 4. No SISO-resistant strains of Escherichia coli, Klebsiella pneumoniae or P. mirabilis were found. 5. SISO had good antimicrobial activity against most of the investigated species and SISO may still be regarded as one of the clinically useful AGs.     

Antibacterial activities of arbekacin, a new aminoglycoside antibiotic, against methicillin-cephem-resistant Staphylococcus aureus

The in vitro and in vivo antibacterial activities of a new aminoglycoside antibiotic, arbekacin (HBK), against methicillin-cephem-resistant Staphylococcus aureus (MRSA) were compared with those of gentamicin (GM), netilmicin (NTL) and amikacin (AMK). The results obtained were summarized as follows: Compared to other aminoglycoside antibiotics, HBK had the highest antibacterial activities against clinically isolated MRSA (46 strains). Therapeutic effects of HBK against experimental systemic infections with MRSA in mice, were superior to those of GM, NTL and AMK. The ED50's of GM, NTL and AMK were more than 2 mg/mouse. Therapeutic effects of HBK against experimental subcutaneous infections with MRSA in mice were also superior to those of GM, NTL and AMK.     

Study on the drug sensitivity of multiple drug-resistant Staphylococcus aureus

Of clinically isolated Staphylococcus aureus showing resistance to multiple drugs among penicillins (PCs), cephem antibiotics (CEPs), aminoglycosides (AGs), minocycline (MINO) and fosfomycin (FOM), 64 strains were selected for the determination of MIC. Twenty-one drugs were used for the determination of MIC, with ampicillin (ABPC), cloxacillin (MCIPC), cephalothin (CET), cefazolin (CEZ), cefotiam (CTM), cefuroxime (CXM), cefamandole (CMD), cefotaxime (CTX), ceftizoxime (CZX), cefmenoxime (CMX), cefmetazole (CMZ), cefoxitin (CFX), latamoxef (LMOX), cefotetan (CTT), cefoperazone (CPZ), gentamicin (GM), dibekacin (DKB), tobramycin (TOB), amikacin (AMK), MINO, and FOM. MIC80 of each drug at 10(6) CFU/ml were: ABPC, MCIPC, CEZ, CTM, CXM, CTX, CZX, CMX, CFX, LMOX, CTT, CPZ, GM, DKB and TOB greater than 100 micrograms/ml; CET 50 micrograms/ml; CMD and AMK 25 micrograms/ml; CMZ 12.5 micrograms/ml; FOM 6.25 micrograms/ml; and MINO 0.78 micrograms/ml. The ratio of highly resistant strains with MIC greater than 100 micrograms/ml at 10(6) CFU/ml varied according to drug, and a difference tended to be seen in the degree of influence by resistant factors reflected upon MIC, e.g. drugs for which a high resistance of more than 50% was confirmed were ABPC, CXM, CZX, LMOX and TOB, and 20 approximately 30% MCIPC, CTM, CTX, CMX and CFX. MIC on MCIPC which has a correlation of structural activity with methicillin correlated with cephems (CEPs) resistance to a high degree, but many of the so-called new CEPs showed resistance even to the strains with a low MIC on MCIPC. It was assumed that CEPs resistant strains have multiple drug resistant factors based on the fact that such strains showed multiple drug resistance.(ABSTRACT TRUNCATED AT 250 WORDS)     

Serotype and susceptibilities to eight antibiotics of fifty strains of Pseudomonas aeruginosa isolated from clinical specimens and changes in susceptibilities of Pseudomonas aeruginosa to various antibiotics during a period between 1983 and 1986

Efficacies of 8 antibiotics against Pseudomonas aeruginosa in the relation to serotypes and clinical sources were investigated on 50 strains isolated from patients at Nagoya Ekisaikai Hospital between August and September, 1986. Disk sensitivity test was carried out simultaneously for 5 antibiotics including piperacillin (PIPC), cefoperazone (CPZ), cefsulodin (CFS), ceftazidime (CAZ) and amikacin (AMK), using the single-disk method. We also examined changes in susceptibilities of P. aeruginosa to 5 antibiotics including PIPC, CFS, fosfomycin, gentamicin (GM) and AMK during last 4 years (1983-1986). The results are summarized as follows. 1. CAZ and AMK proved to have high antibacterial potencies, and their MIC80's (concentrations to inhibit growth of 80% of objective bacteria) were both 6.25 micrograms/ml. Following these two the order of potencies were; CFS, cefpiramide (CPM), PIPC, CPZ, netilmicin (NTL), and cefmenoxime (CMX). Sixty two percent of the strains of P. aeruginosa showed high resistances (MIC greater than 50 micrograms/ml) to CPM, CPZ, NTL and CFS, 58% to PIPC, and 2% to AMK. 2. With regard to serotypes, strains belonging to type E were less susceptible than those belonging to types G and I. Type E strains showed high resistance to all antibiotics except CAZ and AMK. 3. Strains obtained from pura and secreta were relatively susceptible, while those from urines were resistant, to these antibiotics tested, in general. 4. Good correlation between MIC's obtained with the agar dilution method (MIC less than or equal to 12.5 micrograms/ml) and these with the disk sensitivity test (greater than ? was observed. chi 2 statistical analysis showed that the results obtained with the 2 methods were closely related (P less than 0.01). 5. P. aeruginosa showed fairly high susceptibility to AMK through the recent 4 years (1983-1986). On the other hand, highly resistant strains against CFS, PIPC, FOM and GM increased rapidly during this period.     

Studies on sub-MIC activities of beta-lactam antibiotics and aminoglycoside antibiotics against clinically isolated strain

Sub-MIC range of 8 kinds of beta-lactam antibiotics and 3 kinds of aminoglycoside antibiotics against strain of Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa isolated from clinical source were determined by nephlometic method, and following results were obtained. When 10 strains of S. aureus tested to ampicillin (ABPC), hetacillin (IPABPC), mecillinam (MPC), cephalexin (CEX), cefotaxime (CTX), latamoxef (LMOX), cefatrizine (CFT), cephapirin (CEPR), gentamicin (GM), dibekacin (DKB) and amikacin (AMK), ratio of MIC to MAC were 36.8, 53.6, 156.8, 29.6, 61.6, 34.4, 50.0, 111.2, 9.2, 20.0 and 13.6, respectively. When 10 strains of K. pneumoniae tested to MPC, CEX, CTX, LMOX, CFT, CEPR, GM, DKB and AMK, ratio of MIC to MAC were 409.6, 10.4, 34.4, 123.2, 39.2, 167.2, 5.2, 5.6 and 13.2, respectively. When 10 strains of P. aeruginosa tested against CTX, LMOX, GM, DKB and AMK, ratio of MIC to MAC were 16.8, 38.4, 6.8, 3.2 and 10.4, respectively.     

Evaluation of the mutagenicity of aminoglycoside antibiotics in Salmonella typhimurium and Saccharomyces cerevisiae.

The mutagenicity of aminoglycoside antibiotics (KM, AKM, DKB, RSM, AMK, GM, TOB) has been studied in cells of the bacteria Salmonella typhimurium and in the yeast Saccharomyces cerevisiae. The bacterial strains (Ames') monitor reverse mutation (point mutation) and the yeast strain D5 monitors mitotic crossing-over, mitotic gene conversion and point mutation. None of these antibiotics demonstrated any mutagenic activities in either the bacteria or the yeast.     

Therapeutic effects of micronomicin on experimental infections in mice by intravenous administration

Protective effects of intravenous administration of micronomicin (MCR) on mouse experimental infections were investigated. Mice were better protected by intravenous administration in S. marcescens T-55 experimental infection than subcutaneous administration. No remarkable differences were found between the two administrations in cases of P. aeruginosa BMH No. 1 and E. coli GN 2411-5 infections. Intravenous administrations of MCR, gentamicin (GM), dibekacin (DKB), amikacin (AMK) and sisomicin (SISO) protected the infection of P. aeruginosa BMH No. 1 in a similar extent. MCR was more effective intravenously than AMK; DKB and AMK; DKB, AMK and SISO in experimental infections of E. coli GN 2411-5; S. marcescens T-55; P. aeruginosa KY-8510 harboring aminoglycoside inactivating enzyme AAC(6')-4, respectively.