盐酸左旋氧氟沙星对临床分离细菌的MIC测定及药敏实验总结

盐酸左旋氧氟沙星是新型的氟喹诺酮类药物,抗菌谱广,对革兰氏阳性及阴性需氧菌均有较好的抗菌作用。本文研究采用微量药敏法及纸片法测定盐酸左旋氧氟沙星体外抗菌活性,并与其他5种药物比较,结果表明盐酸左旋氧氟沙星对革兰氏阴性菌具有良好抗菌作用,尤以对肺炎克雷伯氏菌、坂崎肠杆菌。臭鼻克雷伯氏菌、阴沟肠杆菌、费劳他枸橼酸菌作用更为突出,其敏感率为100％,比头孢呋辛、头孢唑啉、氨苄青霉素强,与氧氟沙星、乙基西羧霉素相当。     

头孢哌酮与氧哌嗪青霉素、青霉烷砜及氨基甙抗生素对绿脓杆菌协同抗菌作用的初步研究

头孢哌酮(cefoperazone)是一个新型第三代头孢菌素,具有广泛的抗菌活性,对多种革兰氏阴性杆菌需氧或厌菌,尤其是对多价耐药的绿脓杆菌具有较强的抗菌作用。本文报道用微量法(微量稀释及棋盘法)测定头孢哌酮与氧哌嗪青霉素、青霉烷砜,妥布霉素及庆大霉素单用和合用对20株多价耐药性绿脓杆菌的协合抗菌作用。本实验菌株系选用对庆大     

成都地区几种常用氟喹诺酮类药体外及体内抗菌活性比较

六种氟喹诺酮类药 (司帕沙星、妥舒沙星、环丙沙星、氧氟沙星、氟罗沙星及诺氟沙星 )对成都地区 780株临床分离的致病菌 ,其中革兰阳性菌 3 45株 ,革兰阴性菌 40 0株 ,厌氧菌 3 5株 ,进行体外抑菌试验 ,对其中体外抗菌作用强的三种药物进行感染小鼠败血症体内保护试验。体外MICs测定结果表明对MSSA与MSSE及MRSA与MRSE均以司帕沙星与妥舒沙星为最强 ,他们的MICs范围分别为 0 .0 0 4～ 2mg/L及 0 .0 1 5～ 1 6mg/kg ,大多敏感。对化脓性链球菌、粪肠球菌、乙型溶血性链球菌及肺链球菌亦呈现强抗菌活性MICs为 0 .0 0 88mg/L ,抗菌活…     

噻吗灵(羟羧氧酰胺菌素)临床前药理研究与应用概述

噻吗灵又称羟羧氧酰胺菌素,属非典型的β—内酰胺类中的氧头孢烯类抗生素。本品抗菌谱广,抗菌作用强,对β—内酰胺酶十分稳定。对金葡菌的MlC_(90)为6.25—12.5mg/L,肺炎链球菌的MlC_(90)为1.56mg/L,对其它革兰氏阴性菌如流感嗜血杆菌、奇异变形杆菌、克氏肺炎杆菌及脆弱拟杆菌等均高度敏感,它们的MlC_(50)均小于0.78mg/L。对耐庆大霉素、妥布霉素、头孢噻吩和氨雅苄青霉素的沙雷氏菌、肺炎杆菌本品仍敏感。噻吗灵能有效地保护包括头孢唑啉耐药的大肠杆菌。变形杆菌与流感嗜血杆菌感染的小鼠。对单一绿脓杆菌感染或绿脓杆菌与大肠杆菌混合感染的小鼠本品也有显著的保护作用,且优于其它第三代头孢菌素。本品在体内血浆半衰期较长为2.5～2.8小时,可供静脉或肌肉注射应用。本文还对该药的临床应用作了简要介绍。     

国产妥布霉素和阿泊拉霉素对绿脓杆菌体外抗菌活力的研究

本文简要报导国产妥布霉素、阿泊拉霉素对临床分离的90株绿脓杆菌的体外抗菌活力。验室结果表明:妥布霉素和阿泊拉霉素在体外对绿脓杆菌有较高抗菌活力。MIC50分别为0.8和3.12mg/ml。与丁胺卡那霉素和庆大霉素基本一致,对卡那霉素和庆大霉素的多数耐药     

氧氟沙星抗菌活性研究

氧氟沙星(氟嗪酸,Ofloxacin)系第三代喹诺酮类抗菌药物,对革兰氏阳性菌和阴性菌均有较强的抗菌活性。一、体外抗菌活性测定:使用60株试验菌,测定了MIC值(最低抑菌脓度)。实验结果表明:氧氟沙星对革兰氏阴性菌(大肠杆菌MIC=0.05μg/ml,克雷伯氏菌MIC=0.2μg/ml,阴沟杆菌MIC=0.1—0.78μg/ml等的活性相当于或略好于甲氟沙星,     

雪胆素的药效学试验

目的:了解雪胆素片的清热解毒功能,为该制剂的进一步开发及临床用药提供参考依据。方法:体外抗菌活性测定,采用琼脂二倍稀释法测定雪胆素片对受试菌株的最低抑菌浓度;体外抗病毒活性测定,用10日鸡胚孵化方法测定雪胆素片的最低病毒抑制浓度;用小鼠耳肿胀试验,大鼠关节炎试验了解其抗炎作用;用内毒素制成兔子发热模型,了解雪胆素片的降体温作用。结果:提示雪胆素片对革兰氏阳性菌和阴性菌均有抗菌活性,雪胆素片对革兰氏阳性菌的MIC为<0.00036～0.75mg.ml-1。对革兰氏阴性菌的MIC为0.0056～1.5mg.ml-1。雪胆素片对流感病毒的最小抑制浓度约…     

氧氟沙星注射液抗菌效应研究

氧氟沙星系化学合成的第三代喹诺酮类抗菌药,对革兰氏阳性、阴性菌皆有显著的抗菌活性,本文对山东某厂研制的氧氟沙星(OFX)注射液,以吡哌酸(PPA)作为对照比较,对临床分离的246株菌进行了抗菌药效观察,两药抗菌谱皆较广,从两药的MIC值比较OFX远比PPA的抗菌作用强,其中OFX对革兰氏阳性菌,枯草杆菌、金葡菌、分别比PPA强80和40倍;对革兰氏阴性菌、变形杆菌、痢疾杆菌、枸橼酸杆菌,大肠杆菌和绿脓     

偶氮甲基利福霉素、利福平与磺胺增效剂联合用药对耐庆大霉素的革兰氏阴性菌的体外

本文采用棋盘法测定了偶氮甲基利福霉素(FCE_(22280))、利福平(RFP)与磺胺增效剂(TMP)联用对72株临床分离的对庆大霉素耐药的革兰氏阴性菌的体外抗菌作用。实验结果表明FCE_(22280)与TMP联合用药对所试的72株革兰氏阴性菌中有13株菌呈现有协同作用(18.06％),26株菌株呈现相加或不变作用(36.1％),相当一部分菌株     

新型喹诺酮类抗菌剂IMB-86001的体外抗菌活性研究

IMB—86001系我所合成室新研制的第三代喹诺酮类抗菌药物,我们对合成样品进行了体外抗菌活性研究。本文报道了IMB—86001的体外抗菌活性,并与其它喹诺酮类药物进行了比较。实验结果表明:IMB—86001是一个广谱强效喹诺酮类抗菌药,其对革兰氏阳性(G~+)及阴性(G~-)菌均有胶强的抗菌活性,对G~-菌的抗菌作用更强,如对大肠杆菌、肺炎杆菌、变形杆菌、     

Evaluation of antibiotic-loaded collagen-hyaluronic acid matrix as a skin substitute

The 1-ethyl-(3-3-dimethylaminopropyl) carbodiimide hydrochloride-crosslinked collagen-hyaluronic acid (HA) matrices containing tobramycin or ciprofloxacin as an antibiotic agent were fabricated for the control of wound contamination and characterized with respect to morphology, mechanical strength, in vitro release, antibacterial activity and cytotoxicity. For the tobramycin loaded matrix, the antibacterial capacity increased with the drug loading. Tobramycin and ciprofloxacin loaded matrices maintained their antibacterial effects for over 96 and 48 h, respectively. However, cell viability testing revealed that 0.4 mg/ml of ciprofloxacin has a cytotoxic effect on fetal human dermal fibroblasts. The effects of the bilayered collagen-HA matrices containing tobramycin and growth factors were also evaluated using an in vivo full thickness dermal defect model. Though the tobramycin incorporated collagen-HA matrix had no significant effect on wound healing compared with the control, the tobramycin incorporated matrix containing basic fibroblast growth factor or platelet-derived growth factor significantly enhanced wound healing. This study demonstrates the potential efficacy of crosslinked collagen-HA matrix containing antibiotics and growth factors for defective skin tissue replacement and infection prevention.     

In vitro activity of isepamicin and other aminoglycosides against clinical isolates of Gram-negative bacteria causing nosocomial bloodstream infections.

BACKGROUND AND PURPOSE: Isepamicin is a newly introduced aminoglycoside in Taiwan. Since in vitro data for isepamicin against nosocomial Gram-negative bloodstream infection from Taiwan are limited, we compared the activity of isepamicin, amikacin, gentamicin and tobramycin against nosocomial Gram-negative blood isolates. METHODS: A total of 247 non-duplicate nosocomial blood isolates of Gram-negative bacteria collected between January 2003 and December 2003 in a major teaching hospital in Taiwan were tested for their in vitro susceptibilities to gentamicin, tobramycin, amikacin, and isepamicin using the agar dilution method. The isolates included Escherichia coli (31 isolates), Klebsiella pneumoniae (31), Enterobacter cloacae (30), Serratia marcescens (31), Morganella morganii (21), Citrobacter freundii (10), Pseudomonas aeruginosa (31), Acinetobacter baumannii (31), and Stenotrophomonas maltophilia (31). RESULTS: Overall, isepamicin had high antibacterial activity against the tested Gram-negative bacteria. For the 154 Enterobacteriaceae isolates, isepamicin had the lowest minimum concentration inhibiting 90% of isolates (MIC90) among the tested drugs, while its resistance rate (3.9%) was equal to that of amikacin (3.9%) and lower than those of tobramycin (18.2%) and gentamicin (21.4%). For the 93 of non-fermentative Gram-negative bacilli isolates, isepamicin had the lowest MIC90, and a resistance rate (23.7%) lower than those of amikacin (27.9%), tobramycin (38.7%) and gentamicin (40.9%). CONCLUSIONS: The in vitro activity of isepamicin against Gram-negative bacteria isolates was equal or similar to amikacin and superior to other tested aminoglycosides. In view of its potential for less nephrotoxicity and ototoxicity than other aminoglycosides, isepamicin is a drug of choice for the empirical treatment of nosocomial infections caused by Gram-negative bacteria.     

In vitro tobramycin elution analysis from a novel beta-tricalcium phosphate-silicate-xerogel biodegradable drug-delivery system

This in vitro research analyzed local tobramycin elution characteristics from a novel, biodegradable drug delivery system, consisting of a beta-TCP bone substitute, VITOSS trade mark, encapsulated with silicate xerogel prepared by the sol-gel process. Tobramycin elution from silicate-xerogel-encapsulated VITOSS was compared directly with non-silicate-xerogel-encapsulated VITOSS to assess whether xerogels are effective in delivering greater tobramycin quantities in a controllable, sustained manner crucial for microbial inhibition. Tobramycin elution characteristics indicate an initial release maximum during the first 24 h that diminishes gradually several days after impregnation. The copious tobramycin quantity eluted from the VITOSS/silicate-xerogel systems is attributed to various factors: the intrinsic ultraporosity and hydrophilicity of VITOSS, the ability of tobramycin to completely dissolve in aqueous media, tobramycin complexation with highly polar SO(4) (2-) salts that further assist dissolution, and ionic exchanges between VITOSS and the environment. Silicate-xerogel-encapsulated VITOSS eluted 60.65 and 61.31% of impregnated tobramycin, whereas non-silicate-xerogel-encapsulated VITOSS eluted approximately one-third less impregnated tobramycin, at 21.53 and 23.60%. These results suggest that silicate xerogel optimizes tobramycin elution because of its apparent biodegradability. This mechanism occurs through xerogel superficial acidic sites undergoing exchanges with various ions present in the leaching buffer. Tobramycin elution kinetics were evaluated, and demonstrate that first-order elution rate constants are considerably less when silicate xerogels are employed, following a more uniform exponential decay-type mechanism, thus bolstering controlled release. Overall, tobramycin elution rates adhere to linear-type Higuchi release profiles. Elution rate constants are initially first order, and taper into zero-order elution kinetics in the latter stages of release. Because VITOSS and silicate xerogel are completely biodegradable, essentially all impregnated tobramycin will be delivered to the surgical site after implantation.     

Comparative studies on activities of gentamicin, sisomicin, tobramycin and amikacin (BB-K8) against Pseudomonas sp

Activities of gentamicin, sisomicin, tobramycin and amikacin against 561 strains of Pseudomonas sp. bacilli were evaluated. Tobramycin was from two to eight times more active against Pseudomonas sp. than gentamicin. No strains resistant to amikacin were encountered. Correlation between the size of the growth inhibition zone and minimal inhibitory concentration was determined as regression lines for all the tested antibiotics. Sisomicin and tobramycin showed lowest correlation, and gentamicin and amikacin good correlation.     

Shieh medium supplemented with tobramycin for selective isolation of Flavobacterium columnare (Flexibacter columnaris) from diseased fish.

Tobramycin was found to be less inhibitory to Flavobacterium columnare (formerly Flexibacter columnaris) than to other fish-associated bacteria. The selective capacity of Shieh medium, an isolation medium described for this species, was markedly enhanced by adding tobramycin at a concentration of 1 microgram/ml.     

Leaching of tobramycin from PMMA bone cement beads

The in vitro leaching characteristics of tobramycin from acrylic resin (PMMA) bone cement beads have been determined by a radioimmune assay. Tobramycin was incorporated at two concentrations into bone cement beads fabricated from three commercial brands of acrylic resin. Antibiotic leaching followed a curvilinear relationship of the form X . Y = A . X + B . Y. All beads showed similar tobramycin leaching rates over time but the initial amount of leached material differed with the amount of tobramycin incorporated in the bead and the source of the PMMA bone cement. The data indicate that tobramycin-impregnated PMMA beads permit antibiotic leaching at a controlled rate compatible with possible clinical application.     

Incorporation of tobramycin into biomimetic hydroxyapatite coating on titanium

Calcium phosphate coatings containing an antibiotic were produced on titanium alloy (Ti6Al4V) implants using a biomimetic approach. Thin, amorphous calcium phosphate (ACP) coatings were first deposited onto Ti6Al4V plates by immersion in 5 times concentrated simulated body fluid (SBF), for 24h at 37 degrees C. The ACP-coated implants were then immersed in a supersaturated calcium phosphate (SCP) solution containing 0, 100, 200, 400, 600 or 800 mg/l of tobramycin for 48 h at 37 degrees C. A carbonated hydroxyapatite (CHA) layer, approximately 40 microm thick, was formed. Approximately 3 microg/mg of tobramycin was co-precipitated with the CHA crystals onto titanium alloy plates, using 800mg/l tobramycin in the coating solution. For comparison, plasma-sprayed calcium phosphate coatings were also immersed in solutions containing 100, 200, 400 or 1,000 mg/l of tobramycin for 10, 40 min, or 48 h. A maximum of about 0.3 microg/mg could be adsorbed onto the plasma-sprayed calcium phosphate coating with the comparable concentration of 800 mg/l in solution. The dissolution of coating and release of tobramycin were also measured in vitro using saline solution buffered at pH 5.0 or 7.3 at 37 degrees C. The release rate of tobramycin was faster at pH 7.3 than at pH 5, with 50 and 4 microg/ml/min, respectively. Tobramycin released from the biomimetic-coated plates could inhibit growth of Staphylococcus aureus bacteria. The result of this study, therefore, indicates that the biomimetic CHA coatings containing antibiotics could be used to prevent post-surgical infections in orthopaedic or trauma.     

The licorice pentacyclic triterpenoid component 18β-glycyrrhetinic acid enhances the activity of antibiotics against strains of methicillin-resistant <Emphasis Type="Italic">Staphylococcus aureus</Emphasis>

This study aimed to identify compounds that enhance the activity of current antibiotics against multidrug-resistant bacteria. Screening of a 350+ compound proprietary small molecules library revealed that the Glycyrrhiza glabra (licorice)-derived triterpenoid 18β-glycyrrhetinic acid (18β-GA) potentiated the antibacterial activity of certain antibiotics against Staphylococcus aureus. Here, we evaluated the ability of pentacyclic triterpenoids to potentiate the activity of antibiotics against strains of methicillin-resistant S. aureus (MRSA). Checkerboard assays were used to assess the minimum inhibitory concentration (MIC) of tobramycin and ten pentacyclic triterpenoids against S. aureus. The effect of 18β-GA on the MIC of different antibiotics against MRSA was also determined in an in vitro airway MRSA infection model. 18β-GA enhanced the bactericidal activity of the aminoglycosides tobramycin, gentamicin and amikacin, and of polymyxin B against two MRSA strains, reducing the MIC of these antibiotics 32–64-fold [fractional inhibitory concentration index (FICI) of 0.12–0.13]. Other β-amyrin triterpenoids and α-amyrin triterpenoids did not exert such synergistic effects. 18β-GA did not enhance the activity of antibiotics from other structural classes against the MRSA strains. In an air-exposed airway epithelial cell culture, 18β-GA enhanced the bactericidal activity of tobramycin and polymyxin B against the MRSA strain. These data demonstrate the potential of 18β-GA to synergise with certain types of antibiotics to eliminate strains of MRSA.     

In vitro and in vivo synergy between ceftriaxone and aminoglycosides againstPseudomonas aeruginosa

The antibacterial interaction between ceftriaxone and the aminoglycosides tobramycin, gentamicin and amikacin againstPseudomonas aeruginosa was investigated in vitro and in experimental systemic infections of the mouse. In vitro synergy was observed in 70% of the strains with tobramycin, 67.5% with gentamicin, and 77.5% with amikacin. Synergistic bactericidal activity was demonstrated with all three aminoglycosides in combination with ceftriaxone. In line with these in vitro results, synergism against most isolates also occurred in mice. In leukopenic mice, the addition of ceftriaxone resulted in a more than 2.5-fold reduction of the aminoglycoside dose necessary for antiinfective protection, although ceftriaxone alone was only marginally active against the pathogen used in immunocompromised animals.     

Modulation of in vitro natural cell-mediated activity against enteropathogenic bacteria by simple sugars.

Lymphoid cells from mouse Peyer's patches and spleens were tested in a 2-h in vitro assay for their natural activity against the enteropathogenic bacteria Salmonella typhimurium, Salmonella enteritidis, Salmonella tel aviv, and Shigella sp. X16. The antibacterial activity expressed by normal cells was detected against all the bacterial strains tested with the exception of Peyer's patch lymphocytes against S. tel aviv and splenocytes against Shigella sp. X16. To determine whether the different expression of natural antibacterial activity might be due to lectin-like proteins interacting with the saccharidic moieties of the bacterial wall, 11 simple sugars were preincubated with the effector cells before the in vitro assays. We found that some of them could block the natural antibacterial activity as well as induce antibacterial activity when this was not spontaneously expressed. Interestingly, a different panel of sugars among those employed was observed to affect the antibacterial activities for each of the above-mentioned bacterial targets and each effector cell. However, the same panel of sugars was able to block or stimulate the lymphocyte activity when bacteria with the same somatic antigens as two substrains of S. typhimurium and one strain of Salmonella schottmuelleri were employed. To further investigate the interaction between effector cells and bacteria, effector cells or Shigella sp. X16 targets were treated with proteolytic, glycolytic, and lipolytic enzymes before the in vitro assays. Furthermore, EDTA was used to analyze the role of divalent cations in this experimental system. The results obtained suggest that lectin-like proteins playing a role in this interaction are present not only on lymphocytes but also on bacteria and that divalent cations are essential for the expression of in vitro antibacterial activity.