肺炎克雷伯杆菌对氨基糖苷类耐药机制的研究

目的了解肺炎克雷伯杆菌对氨基糖苷类药物的耐药情况,同时进行基因分型,确立耐药基因的位点和种类,进一步研究不同基因型对庆大霉素、阿米卡星、奈替米星、链霉素、妥布霉素的耐药情况以及产超广谱β-内酰胺酶与非产超广谱β-内酰胺酶同基因型的关系。方法收集浙江省人民医院检验医学中心2007年2月至2007年8月分离鉴定菌株31株,采用Kirby-Bauer法测定肺炎克雷伯杆菌对庆大霉素、阿米卡星、奈替米星、链霉素、妥布霉素的敏感性,并采用聚合酶链反应(PCR)及电泳测定技术分析氨基糖苷类修饰酶基因型。结果从浙江省人民医院分离到的31株肺炎克雷伯杆菌对庆大霉素、奈替米星、链霉素的耐药率分别为58.1%、6.5%、61.3%,阿米卡星和妥布霉素都未发生耐药;含一种基因型的有6株,两种基因型的有10株,三种基因型的有8株,四种基因型的有3株;产ESBLs有4株,其中含aac(3)-Ⅱ、aac(6″)-Ⅱ产ESBLs的百分率达75%。结论必须加强对细菌耐药性变迁的动态监测,更好地指导临床合理用药。     

氨基糖苷类抗生素在临床的合理使用

<正>氨基糖苷类抗生素是一类在水溶液中稳定性好、作用强的抗生素,碱性可增强其抗菌作用;本类药物主要包括:链霉素、庆大霉素、卡那毒素以及阿米卡星、奈替米星等药物。氨基糖苷类主要作用于革兰阴性杆菌,作用范围大、强而持久。然而,氨基糖苷类抗生素的治疗指数狭窄,不良反应较常见,其中部分毒性反应是不可逆的,     

氨基糖苷类抗生素在儿科领域中的应用问题

氨基糖苷类抗生素（Aminoglycosides）自１９４４年链霉素发现以来，已有半个多世纪，从它们的来源可分为三类：（１）源于链霉菌属培养液，如链霉素、新霉素、卡那霉素、妥布霉素、核糖霉素；（２）源于小单包菌属培养液，如庆大霉素、西索霉素、小诺霉素等；（３）人工合成，如阿米卡星、奈替米星、依替米星等。氨基糖苷类抗生素在儿科领域中如何合理使用，必须从疗效和安全性两方面去分析。１抗菌作用特点１．１对革兰阴性杆菌作用范围大、强而持久本类药物对大多数革兰阴性杆菌如大肠杆菌、克雷白菌属、肠杆菌属，变形杆菌属、志贺菌属…     

鲍曼不动杆菌临床分离株16S rRNA甲基化酶基因研究

目的 了解临床分离鲍曼不动杆菌(ABA)氨基糖苷类药物耐药性与16S rRNA甲基化酶基因存在的关系,探讨多药耐药机制.方法 收集临床标本20株鲍曼不动杆菌,采用K-B法测定细菌对卡那霉素、阿米卡星、妥布霉素、庆大霉素、奈替米星的敏感性;采用PCR法检测armA、rmtA、rmtB、rmtC和rmtD 5种16S rRNA甲基化酶基因.结果 19株鲍曼不动杆菌对上述5种氨基糖苷类药物全部耐药,1株对阿米卡星敏感,对另外4种表现为中度耐药.基因检测显示armA阳性率为90％,且armA基因存在变异,未检测到rmtA、rmtB、rmtC和rmtD基因.结论 鲍曼不动杆菌对氨基糖苷类药物耐药情况严重,16S rRNA甲基化酶基因armA为本次临床分离菌株耐药的主要原因,且armA基因存在变异.     

儿科患者鲍曼不动杆菌氨基糖苷类修饰酶基因的表达

目的 研究从儿科肺炎患者中分离的鲍曼不动杆菌对氨基糖苷类抗生素的耐药性和常见的7种氨基糖苷类修饰酶基因特征.方法 56株鲍曼不动杆菌(AB)收集自2006年分离的儿科临床肺炎患儿的深部痰培养标本,均采用 VITEK-32全自动微生物鉴定仪GNI和GNS卡进行细菌鉴定和药敏试验.氨基糖苷类修饰酶基因检测采用聚合酶链式反应(PCR)方法.结果 检测的56株鲍曼不动杆菌菌有8株呈多重耐药性,阳性率14.29%,8株多重耐药菌对氨基糖苷类药物阿米卡星、妥布霉素和庆大霉素均耐药,其余菌株对氨基糖苷类药物均敏感,氨基糖苷类药物的耐药率14.29%.除呋喃妥因及β-内酰胺类抗生素氨苄西林、头孢唑林和头孢曲松外其它抗生素的耐药率均在15%以下.7种氨基糖苷类修饰酶基因中检出2株aac(3)-Ⅱ(3.57%),2株aac(6')-Ib(3.57%),4株aac(6')-Ⅱ(7.14%),6株ant(3")-Ⅰ(10.71%);aac(3)-Ⅰ、ant(2")-Ⅰ和aac(6')-Ⅰad均阴性.对3种氨基糖苷类抗生素耐药的菌株均检出了氨基糖苷类修饰酶基因.结论 (1)儿科患者虽然极少应用氨基糖苷类抗生素,但由于氨基糖苷类修饰酶基因可借助于整合子、转座子和质粒等在同种和异种细菌间传播,使其对氨基糖苷类抗生素也产生了一定的耐药性.(2)鲍曼不动杆菌儿科患者分离株对阿米卡星、庆大霉素和妥布霉素的耐药与aac(3)-Ⅱ、aac(6')-Ib、aac(6')-Ⅱ和ant(3")-Ⅰ四种基因有关.不同地区细菌的修饰酶基因有很大差异,而儿童与成人患者亦有不同,因此要重视儿科患者鲍曼不动杆菌氨基糖苷类抗生素耐药性和耐药基因研究.     

革兰氏阴性菌对氨基糖苷类抗生素耐药机制的研究进展

氨基糖苷类抗生素对需氧革兰氏阴性菌有强大抗菌活性。链霉素为最早应用于临床的氨基糖苷类 ,对结核杆菌有良好作用 ,但近年来结核杆菌对本品的耐药性日益增加。随后出现的卡那霉素、庆大霉素、妥布霉素、奈替米星及阿米卡星等对各种需氧革兰氏阴性杆菌 ,如大肠埃希氏菌、克雷伯氏菌属、肠杆菌属、志贺氏菌属、柠檬酸杆菌属等均具有强大抗菌活性。随着氨基糖苷类抗生素在临床上的广泛使用 ,细菌对氨基糖苷类可呈不同程度的耐药。对北京地区 1995～ 1997年临床分离出的菌株调查显示 ,这些分离株对卡那霉素的耐药率最高 (36 .8% ) ,其次为新霉素 (31.6 % ) ,再次为庆大霉素 (2 5 .3% ) ,对阿米卡星的耐药率最低(5 .5 % )。北京儿童医院报告 1997～ 1999年度常见革兰氏阴性菌对氨基糖苷类耐药情况为大肠埃希氏菌和肠杆菌属对庆大霉素耐药率较高 ,分别为 5 3%和 4 1%。克雷伯氏菌属对氨基糖苷类耐药率均较高 ,其中 ,对庆大霉素的耐药率为 74 % ,妥布霉素为 76 % ,阿米卡星为 4 8%。其耐药率表现为庆大霉素 >妥布霉素 >阿米卡星。     

氨基糖苷类药物衍生荧光性质的研究及应用

氨基糖苷类药物庆大霉素、卡那霉素及小诺霉素本身有微弱荧光,当它们在碱性条件下加入L-精氨酸、硼酸并加热水解后,可产生较强荧光,这是因为氨基糖苷类药物水解后成为糖,糖在精氨酸,硼酸存在下可产生强的荧光.由此可建立庆大霉素、卡那霉素及小诺霉素这类氨基糖苷类抗生素衍生荧光法.庆大霉素、卡那霉素均在1.0×10-6～1.5×10-5 mol/L范围内与荧光强度呈良好线性关系(r=0.9996,r=0.9994),小诺霉素在4.0×10-7～8.0×10-6 mol/L范围内与荧光强度呈良好线性关系(r=0.9986),三者检出限分别为5.8×10-7,6.1×10-7和3.0×10-8 mol/L.     

从烧伤创面分离的9种革兰氏阴性杆菌对丁胺卡那霉素、托普霉素和庆大霉素体外敏感性比较

自六十年代以来,临床病例中革兰氏阴性杆菌感染发生率明显增加。在革兰氏阴性杆菌中不但有些菌种如绿脓杆菌,变形杆菌,沙雷氏杆菌等对许多抗生素天然耐药,而且过去对氨苄青霉素、卡那霉素等敏感的一些菌种近几年来耐药性也明显增加。革兰氏阴性杆菌对抗生素的耐药性可借助R因子传递给敏感菌株,造成耐药菌株在临床上广泛传播,给抗生素的选择带来困难。氨基糖苷类抗生素是一类治疗革兰氏阴性杆菌感染的重要抗生素,随着细菌对氨基糖苷类抗生素耐药机制的阐明,使这类抗生素的化学结构改造工作取得很大的成功。托普霉素和丁胺卡那霉素已应用于临床,在治疗革兰氏阴性杆菌,特别是绿脓杆菌和庆大霉素耐药菌株感染方面增加了新的武器。为了观察革兰氏阴性杆菌对这两种新的氨基糖苷类抗生素的敏感性,我们以试管稀释法,测定丁胺卡那霉素,托普霉素和庆大霉素对从烧伤病人创面上分离到的9种革兰氏阴性杆菌的最小抑菌浓度(MIC),比较它们的抗菌活力,并观察它们之间的交叉耐药性。     

雷氏普罗威登斯菌对碳青霉烯类耐药与氨基糖苷类异质性耐药研究

目的 分析雷氏普罗威登斯菌对碳青霉烯类药物耐药机制与氨基糖苷类药物异质性耐药现象的探索。方法 对2016—2021年收集的4株多重耐药的雷氏普罗威登斯菌(multidrug resistant Providencia Rettgeri, MRPRE)临床分离株的耐药性和携带的耐药基因进行分析。采用异质性耐药菌谱分析与亚抑菌浓度抗生素诱导实验探索庆大霉素异质性耐药菌株对氨基糖苷类和碳青霉烯类抗生素的适应性耐药。结果 本研究共收集4株MRPRE，其中3株检出bla_NDM-1基因，对碳青霉烯类高度耐药，同时对第一、二、三代头孢菌素、氨曲南、复方磺胺甲恶唑、喹诺酮类药物耐药。1株未检出碳青霉烯酶基因，但对氨基糖苷类抗生素异质性耐药，在亚抑菌浓度庆大霉素诱导下，庆大霉素MIC值由8 μg/mL上升至64 μg/mL，亚胺培南MIC值由2 μg/mL上升至8 μg/mL，出现适应性耐药。结论 雷氏普罗威登斯菌可携带bla_NDM-1对碳青霉烯类抗生素高度耐药，同时表现对多种抗生素的多重耐药。异质性耐药菌株在亚抑菌浓度庆大霉素诱导下可出现庆大霉素与亚胺培南的...     

大肠埃希菌对氨基糖苷类抗生素的耐药谱及其产ESBLs的研究

目的了解临床分离的54株大肠埃希菌对氨基糖类苷类抗生素的耐药谱及产ESBLs情况,分析氨基糖苷类修饰酶AAC(3)-II的检出率及该酶的一些特征。方法采用MIC法测定临床分离的54株大肠埃希菌对7种氨基糖苷类抗生素的耐药谱,用NCCLS推荐的酶抑制剂增强纸片扩散法检测产ESBLs菌株,并通过聚合酶链反应、克隆测序和测定重组菌耐药谱对aac(3)-II基因进行研究。结果54株大肠埃希菌对阿米卡星、庆大霉素、卡那霉素、妥布霉素、链霉素、大观霉素和奈替米星的耐药率分别为14.8%、77.8%、59.3%、66.7%、68.5%、61.1%、22.2%;共检测出产ESBLs菌株34株,占63.0%;aac(3)-II基因在54株大肠埃希菌中检出率为88.5%;质粒转化菌产ESBLs且同时检出aac(3)-II基因。重组菌BL21(DE3)/pET26::aac(3)-II对庆大霉素和卡那霉素有耐药性,对其余5种氨基糖苷类抗生素没有表现出耐药性。结论大肠埃希菌对庆大霉素的耐药率最高,对阿米卡星的耐药率最低;耐氨基糖苷类抗生素的大肠埃希菌与其产ESBLs有相关性;重组菌BL21(DE3)/pET26::aac(3)-II仅对庆大霉素和卡那霉素产生耐药。     

Antimicrobial activity of cefotiam combinations against Enterobacteriaceae moderately susceptible or resistant to this new cephalosporin

The interaction of cefotiam with each of the four aminoglycosides gentamicin, tobramycin, netilmicin and amikacin were studied by the broth microdilution method ("checkerboard" technique) against 36 strains of Enterobacteriaceae chosen for their moderate susceptibility (MIC: 4-32 mg/l) or resistance (MIC: 64-512 mg/l) to cefotiam. A high rate of synergistic combinations was found with all the aminoglycosides: 81% with gentamicin, 76% with amikacin, 67% with tobramycin and netilmicin. The therapeutic value of these interactions appeared excellent.     

Post-antibiotic effect of isepamicin compared to that of other aminoglycosides

Isepamicin is a new aminoglycoside drug derived from gentamicin, which is more stable than other aminoglycosides to inactivating enzymes and experimentally is less nephrotoxic than gentamicin or amikacin. In this work a comparative study was carried out on the antibacterial activity (MIC and lethality curves) and the post-antibiotic effect (PAE) of different concentrations of isepamicin, netilmicin and gentamicin on pure cultures of S. aureus and E. coli. The MIC and curves of lethality were determined by conventional methods. The PAE was determined after exposure of the bacterial culture to the antimicrobial one for 1 h at 37 degrees C in a bath with stirring. Elimination of the drug was made by the dilution method. Isepamicin was found to have a MIC four times greater than netilmicin and gentamicin. Its activity over time was similar to that exhibited by other aminoglycosides. At concentrations higher than the MIC, a bactericidal effect was found with the three antibiotics, although isepamicin produced it at lower concentrations. The post-antibiotic effect induced by isepamicin, the same as that of netilmicin and gentamicin, was extensive and depended on the concentration and the strain used. Isepamicin shows antibiotic activity over time and a PAE similar to the other aminoglycosides tested but, unlike them, it has a faster activity, less toxicity and better resistance to inactivating enzymes. For this reason it makes a considerable contribution to antibacterial therapies in severe conditions, including immunodepressed patients who require long-term treatment.     

Antimicrobial resistance of enterococci in Turkey

Susceptibility to ampicillin, penicillin, vancomycin and teicoplanin, high-level resistance to aminoglycosides (gentamicin and streptomycin) and β-lactamase production were investigated among 264 consecutive clinical enterococcal isolates in Turkey. Disc diffusion test was used to detect resistance to ampicillin, penicillin, vancomycin and teicoplanin. High-level resistance to aminoglycosides was determined both by standard agar screening and by disc diffusion methods. The values of minimum inhibitory concentration (MIC) of each isolate for ampicillin, vancomycin and teicoplanin were determined by the microbroth dilution technique. The isolates were found to consist of Enterococcus faecalis (78%), Enterococcus faecium (9%) and Enterococcus spp. (12%). In all strains, the penicillin and ampicillin resistance ratios were 27% and 26%, respectively. Enterococcus faecalis was more susceptible to penicillin and ampicillin than the other strains. None of the strains were resistant to glycopeptides. High-level aminoglycoside resistance was found in 16% E. faecalis and 88% E. faecium for gentamicin, and 35% and 44%, respectively, for streptomycin. There were no differences between the two methods used to determine the aminoglycoside resistance rates in the enterococcal isolates. No β-lactamase-producing isolates were detected in either species. In conclusion, to determine the resistance of enterococci to the penicillin group of drugs by the disc diffusion method, both penicillin and ampicillin discs should be evaluated. In serious enterococcal infections, before starting combined therapy, high-level aminoglycoside resistance should be investigated.     

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)     

Mutagenesis of the rapamycin producer Streptomyces hygroscopicus FC904

Rapamycin (RPM) is produced by Streptomyces hygroscopicus FC904 isolated from soil in Fuzhou, China. It is a triene macrolide antibiotic with potential application as an immunosuppressant and drug for human gene therapy. In an attempt to improve rapamycin production, mutation and screening of the parent culture have been carried out. Thousands of survivors were obtained after mutagenesis by NTG (3 mg/ml) and UV (30 W, 15 cm, 30 seconds) of spore suspensions. None showed improved production of RPM. We determined the susceptibility to antibiotics of S. hygroscopicus FC904 by two fold dilutions of antibiotics in oatmeal agar plates. It was found that the strain was resistant to penicillin, erythromycin, RPM, tetracycline and chloramphenicol, but susceptible to mitomycin C (MIC, 10 microg/ml) and aminoglycosides such as gentamicin (MIC, 0.1 microg/ml), kanamycin (MIC, 0.1 microg/ml) and streptomycin (MIC, 0.3 microg/ml). Protoplasts of strain FC904 were prepared after finding the best conditions for their formation. They were treated with gentamicin, erythromycin, mitomycin C and NTG. Surprisingly, gentamicin was especially effective for obtaining higher RPM-producing mutants. Mutant C14 was selected by exposing the protoplasts of the parent strain FC904 to 1 microg/ml of gentamicin at 28 degrees C for 2 hours. A higher RPM-producing mutant (C14-1) was obtained from the protoplasts of mutant C14 treated with gentamicin, and its titer was 60% higher than that of the parent strain FC904 by HPLC analysis. Another improved mutant (C14-2) was obtained from the spores of mutant C 14 treated with 1 microg/ml of gentamicin plus 2 mg/ml of NTG at 28 degrees C for 2 hours. Mutant C14-2 had a titer 124% higher than FC904. The possible mechanism for the effect of gentamicin by using protoplasts or spore suspensions will be discussed, i.e. the possibility of gentamicin being a mutagen or a selective agent.     

Enzymatic modification of aminoglycoside antibiotics by Branhamella catarrhalis carrying an R factor

Fifteen out of 89 clinical strains of Branhamella catarrhalis isolated from patients at the University Hospital of Zaragoza were resistant to aminoglycosides and other antimicrobials. In two strains, B. catarrhalis 220 and B. catarrhalis 115, the resistance to aminoglycosides was associated with synthesis of aminoglycoside-modifying enzymes, namely 3"-O-phosphotransferase [APH(3")] and 3'-O-phosphotransferase [APH(3')]. B. catarrhalis 115 was resistant to ampicillin, streptomycin, kanamycin, neomycin, butirosin, lividomycin, ribostamycin, paromomycin and trimethoprim-sulfamethoxazole and harboured a 32 megadalton (Md) plasmid. The resistance determinants of the latter were transferred to Neisseria subflava by conjugation and to Escherichia coli by transformation. The transconjugant strain presented an antibiotic resistance pattern similar to the donor strain and carried the same plasmid. The transformant strain acquired the 32 Md plasmid but presented, besides the resistance pattern already mentioned, resistance to tetracycline, gentamicin and tobramycin. Resistance to gentamicin and tobramycin was mediated by the synthesis of a 3-N-acetyltransferase. This resistance and the related enzyme were expressed neither in the donor B. catarrhalis strain nor in the transconjugant N. subflava strain.     

In vitro antibacterial activities of telithromycin against clinical isolates of Neisseria gonorrhoeae

In vitro antibacterial activity of telithromycin (TEL) against the isolates of Neisseria gonorrhoeae (212 isolates) derived from urine or genital secretion in 2002 (April to December) was examined in comparison with those of macrolides (erythromycin [EM], clarithromycin [CAM]), penicillins (penicillin G [PCG]), cephems (cefodizime [CDZM], cefixime [CFIX]), quinolones (levofloxacin [LVFX]), tetracyclines (minocycline [MINO]), and aminoglycosides (spectinomycin [SPCM]). The MIC of TEL was ranged from < or = 0.039 to 0.25 microg/mL and the MIC50 and MIC90 of TEL were respectively 0.125 and 0.25 microg/mL, which were the lowest values compared with those of other oral antibacterial agents measured. When compared TEL with other agents in the order of the MIC50 and MIC90, TEL was more superior to EM and CAM (both eight times), MINO (four times and twice), and LVFX (16 and 64 times). The MIC90 of TEL was superior in twice though the MIC50 was the same in comparison with CFIX. The CDZM resistant strain did not exist and SPCM also inhibit growth with 32 microg/mL or less that was the breakpoint MIC excluding one stock though the PCG sensitive strain was only 1.4% in the injection drug. However, clinical breakpoint MIC is not established, but the efficacy of TEL is prospective because of its high antibacterial activity to inhibit growth of all stocks for gonococcus with 0.25 microg/mL. It is expected that TEL can become an oral antibiotic recommended for treatment of gonococcus if dosage and administration are considered.     

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.     

Comparison of the antibacterial activity of amikacin (BB-K8) with other aminoglycosides against pathogens recently isolated from clinical materials (author's transl) ]

We determined the antibacterial activity of amikacin against 1,277 strains of pathogenic bacteria isolated from clinical materials during 1974, including beta hemolytic streptococci, pneumococci, enterococci, Staphylococcus aureus, Staph. epidermidis, Escherichia coli, Klebsiella, Enterobacter, Citrobacter, Serratia, Proteus morganii and Pseudomonas aeruginosa, and compared the minimum inhibitory concentration (MIC) of this drug with gentamicin, dibekacin, tobramycin and kanamycin. 1)Antibacterial activity of amikacin against beta hemolytic streptococci, pneumococci and enterococci was as weak as the other four aminoglycosides, but against Staph. aureus, Staph. epidermidis, various groups of Enterobacteriaceae and Pseudomonas aeruginosa showed amikacin the good antibacterial activity as gentamicin, dibedacin and tobramycin, and also showed the good activity against kanamycin resistant strains. 2) Amikacin has the similar antibacterial spectrum as gentamicin, dibekacin or tobramycin, but its antibacterial activity is generally weakest among these four drugs. 3) On many strains tested the cross resistance is observed between amikacin and one of gentamicin, dibekacin and tobramycin, but several strains of Proteus morganii and Pseudomonas aeruginosa which have rather large MIC against gentamicin, dibekacin or tobramycin showed rather small MIC against amikacin.