Comparative In Vitro Activity of Cefepime against Nosocomial Isolates

Abstract

Cefepime, a new parenteral cephalosporin, was evaluated for its In Vitro antibacterial activity in comparison with other broad-spectrum antibiotics against a total of 445 recently isolated microorganisms of nosocomial origin. Cefepime was highly active against all species of Enterobacteriaceae with minimum inhibitory concentrations (MIC₉₀s) ranging from 0.25-8 μ/ml. Cefepime showed moderate activity against Acinetobacter spp (MIC₅₀ and MIC₉₀, 16 μ/ml) but its activity was superior to that of any drug tested, except imipenem. Against Pseudomonas aeruginosa its activity was comparable to that of ceftazidime and was greater than that of cefotaxime, aztreonam, ciprofloxacin and aminoglycosides. Of all the agents tested, imipenem was the most active compound. Cefepime was active against Staphylococcus aureus and coagulase-negative methicillin-susceptible staphylococci but it had no activity against methicillin-resistant staphylococci and enterococci.     

In Vitro Antibacterial Activity of the New Quinolone Bay y3118 against Clinical Isolates

Summary

The in vitro antibacterial activity of the new fluoroquinolone Bay y3118 against 609 clinical isolates was evaluated. Bay y3118 exhibited activity against a broad spectrum of organisms, including Gram-negative bacilli, Gram-positive cocci, mycobacteria. The activity of Bay y3118 was often superior to that of other quinolones. Against Gram-negative bacilli its activity was similar to that of ceftriaxone, cefotaxime, ceftazidime and imipenem except for Serratia marcescens, Klebsiella pneumoniae, Enterobacter spp. and Xanthomonas maltophilia, where its activity was superior. Gentamicin and piperacillin sometimes were less active. Bay y3118 was active against a large number of Gram-positive cocci. The fluoroquinolones tested were active against all the strains of Mycobacterium tuberculosis, but only Bay y3118 was effective against Mycobacterium avium.     

In Vitro Antifungal Activity of Sertaconazole Against 309 Dermatophyte Clinical Isolates

Abstract

Three hundred and nine strains belonging to 11 species of dermatophyte moulds were tested against sertaconazole following mainly the National Committee for Clinical Laboratory Standards (M38-P) for filamentous fungi. However, several important factors such as the temperature (28°C vs 35°C) and time of incubation (4-10 d vs 21-74 h), have been modified. Sertaconazole was active against all the clinically important dermatophyte moulds involved in human infections tested. Overall geometric mean MIC of sertaconazole was 0.21 μg/ml with a MIC range of 0.01-8 μg/ml. MIC₅₀ and MIC₉₀ were respectively of 0.25 and 1 μg/ml. Sertaconazole was very active against Epidermophyton floccosum, Trichophyton rubrum, Trichophyton tonsurans and Microsporum canis (geometric means 0.08, 0.13, 0.13 and 0.19 μg/ml respectively). Microsporum audouinii had the lowest susceptibility in the study (geometric mean 0.59 μg/ml). Considering MIC₅₀ and MIC₉₀ these differences were significantly in favor of the activity of sertaconazole against E. floccosum (0.06 and 0.5 μg/ml respectively).     

In Vitro Activity of Ampicillin-Sulbactam Against Clinical Multiresistant Acinetobacter baumannii Isolates

Abstract

We evaluated the in vitroactivity of ampicillin-sul-bactam in comparison with that of broad-spectrum antimicrobial agents against Acinetobacter baumannii isolates. Two hundred and twelve clinical isolates collected between January 1993 and March 1995 from two tertiary hospitals located in São Paulo, Brazil were tested for susceptibility by the disk diffusion method against several broad-spectrum antimicrobial agents, including imipenem, ciprofloxacin, ceftazidime, aztreonam, amikacin, and polymyxin B. All strains were susceptible to polymyxin B. The second most active compound was the combination ampicillin-sulbactam (88% susceptibility). Only 79% of the isolates were susceptible to imipenem. Ciprofloxacin was active against 60 (28%) and amikacin against 34 (16%) isolates. Ceftazidime was the most active cephalosporin; however, only 9% of the isolates were susceptible to this compound. Both aztreonam and ampicillin alone showed very poor activity against this species (1% susceptibility). The prevalence of severe infections due to A. baumannii is increasing very rapidly in the tertiary hospitals of São Paulo and there are very few options for the treatment of these infections. Polymyxin B is invariably in vitro active against this species; however, this compound can cause severe side effects and is not commercially available for intravenous use in Brazil and in several other countries. Our results indicated that the combination ampicillin-sulbactam may be an alternative drug for the treatment of infections due to multiresistant A. baumannii; however, further studies are necessary to evaluate the clinical role of this compound for the treatment of severe infections.     

In vitro and In vivo Antitumor Activity of Tiliacorinine in Human Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a fatal cancer with poor prognosis and less than 10% of CCA patients can be offered surgical cure. Conventional chemotherapy results in unfavorable outcomes. At present, plant-derived compounds are gaining interest as potential cancer therapeutics, particularly for treatment-refractory cancers. In this study, antitumor activity of tiliacorinine, the major alkaloid isolated from a tropical plant, on CCA was first demonstrated. Antiproliferative effects of tiliacorinine on human CCA cell lines were investigated using SRB assays. Acridine orange/ethidium bromide staining, flow cytometric analysis and DNA laddering assays were used for apoptotic determination. Apoptosis-related proteins were verified by Western blotting and antitumor activity of tiliacorinine in vivo was demonstrated in CCA xenografted mice. Tiliacorinine significantly inhibited proliferation of human CCA cell lines with IC50 4.5-7 μM by inducing apoptosis through caspase activation, upregulation of BAX, and down-regulation of BclxL and XIAP. Tiliacorinine considerably reduced tumor growth in CCA xenografted mice. These results demonstrated antitumor effects of tiliacorinine on human CCA in vitro and in vivo. Tiliacorinine may be an effective agent for CCA treatment.     

The Antitumor Activity of Meisoindigo against Human Colorectal Cancer HT-29 Cells In Vitro and In Vivo

Abstract

The study was conducted to examine the antitumor activity of meisoindigo on HT-29 cells In Vitro and In Vivo. The cytotoxicity of meisoindigo was evaluated by MTT assay. The related genes and proteins were inspected with RT-PCR and western blot assay respectively, and the effects of meisoindigo on the cell cycle were analyzed by flow cytometry. The efficacy of meisoindigo In Vivo was evaluated in an HT-29 cell xenograft nude mice model. The results show that meisoindigo effectively inhibits HT- 29 cell proliferation (IC₅₀ 4.3 mmol/L), arrests HT-29 cells in G2/ M phase and induces HT-29 cell apoptosis. The downstream genes and proteins of GSK-3β(ser⁹) expression level decrease. Meisoindigo significantly inhibits the HT-29 xenograft tumors growth at the dose of 100 mg/kg. The mechanism of meisoindigo activity against HT-29 cells may be related to its inhibition of glycogen synthase kinase-3β, GSK-3β(ser⁹) phosphorylation in Wnt signaling pathway. These findings indicate the potential value of meisoindigo for the treatment of colorectal cancer.     

放射线照射后NK-92 细胞对人宫颈癌细胞体外杀伤活性的研究

 目的 研究放射线照射后NK-92细胞对人宫颈癌细胞的体外杀伤活性。方法 应用医用电子直线加速器对NK-92细胞进行照射处理(0、400cGy)后，以体外培养人宫颈癌细胞系Hela为靶细胞，以NK-92的敏感细胞株K562作为对照，应用4h^51Cr释放法检测不同效靶比情况下NK-92细胞的杀伤活性。结果 NK-92细胞0cGy照射组，效靶比较低时(1：1、5：1)对Hela细胞杀伤率为15％～33％，随效靶比升高，杀伤率随之上升，10：1时杀伤率显著上升为47％，20：1时杀伤率仅上升了3％；对于K562细胞，杀伤率为33％～69％。400cGy组照射后2d，NK-92细胞对Hela细胞不同效靶比的杀伤率与0cGy组相比稍有降低，其总体杀伤率为14％～47％，对K562细胞杀伤范围在30％～60％之间。结论 放射线照射后的NK-92细胞对人宫颈癌Hela细胞系具有一定的杀伤活性。     

In vivo Antitumor Activity of Hexamethylmelamine against Human Breast, Stomach and Colon Carcinoma Xenografts

We have evaluated the antitumor activity of Altretamine (hexamethylmelamine, HMM) on human carcinoma xenografts serially transplanted in nude mice. Five human breast carcinoma xenografts, MX-1, T-61, MCF-7, R-27 and Br-10, were inoculated subcutaneously into female nude mice. Two human stomach carcinoma xenografts, SC-1-NU and St-4, and three human colon carcinoma xenografts, Co-3, Co-4 and Co-6, were inoculated subcutaneously into male nude mice. One pellet of 17β-estradiol (0.1 mg/mouse) was inoculated subcutaneously in the mice transplanted with MCF-7 when the tumors were inoculated. HMM was administered per os daily for 4 weeks. MX-1 and T-61 tumors regressed completely after treatment with HMM at a dose of 75 mg/kg (the maximum tolerated dose: MTD) for MX-1 and 25 mg/kg for T-61. Br-10 was sensitive, whereas MCF-7 and R-27 were resistant to HMM at its MTD. HMM exerted the most potent antitumor effect against T-61. Against MX-1, it exerted an antitumor effect equivalent to that of cisplatin or cyclophosphamide. In addition, this agent was effective against all stomach and colon carcinoma xenografts, in particular St-4 (T/C%= 10.7: the mean tumor weight of treated group/the mean tumor weight of control group) and Co-3 (T/C%=31.5%) which are insensitive to presently available agents. HMM seems worthy of further clinical investigation as a candidate agent to treat breast, stomach, colon and other carcinomas.     

In Vitro Antibacterial Activity of DX-619, a Novel Des-F (6)-Quinolone Against Clinical Isolates in China

Abstract

The aim of the study was to investigate In Vitro antibacterial activity and bactericidal effect of DX-619 and other nine comparators against 1,101 recently collected clinical bacterial isolates in China. The minimum inhibitory concentrations (MICs) of antimicrobials were determined by a CLSI recommended standard agar dilution method and the minimum bactericidal concentrations (MBCs) were examined by the broth dilution method. Time-kill curves against representative isolates of Staphylococcus aureus, enterococci, and Klebsiellia pneumoniae were also conducted.

DX-619 exhibited excellent antibacterial activity against 1,101 clinical isolates, especially to multi-drug resistant Gram-positive cocci. The MIC₉₀s of DX-619 were ≤0.016 and 0.125 mg/L against methicillin-sensitive and -resistant S. aureus, 0.062 and 0.125 mg/L against methicillin-sensitive and -resistant S. epidermidis, respectively, which were 8-512 and 64-128 fold lower than those of comparative fluoroquinolones. The MIC₉₀s of DX-619 for penicillin-sensitive and -non-sensitive Streptococcus pneumoniae, Enterococcus faecalis and Enterococcus faecium were 0.016, 0.062, 0.25 and 0.5 mg/L, respectively. The MIC₉₀s of DX-619 against Enterobacteriaceae (except for Escherichia coli) and glucose-nonfermenting bacilli were ≤4 mg/L, which were comparable to other comparators. MBCs and time-kill curves showed that DX-619 was a potent bactericidal agent. There was no significant inoculum effect on MICs. But the activities of DX-619 against S. aureus, K. pneumoniae and Pseudomonas aeruginosa were decreased by acidic pH and human serum. DX-619 was a potent antibacterial compound against multi-drug resistant bacteria including Gram-positive cocci, such as S. aureus and enterococci, which may warrant further exploration.     

In- Vitro Activity of Ampicillin/Sulbactam and Other Antibiotics against Clinical Isolates of Haemophilus sp. and Branhamella catarrhalis

Summary

The ampicillin/sulbactam combination is one of several such drug combinations of a beta-lactam and suicide inhibitor having a wide spectrum of activity.

These characteristics induced us to evaluate the in vitro activity of this combination towards 54 strains of Haemophilus sp. (38 beta-lactamase producers) and 20 strains of Branhamella catarrhalis (16 beta-lactamase producers).

All strains were isolated from sputum, sinusal aspiration and tympanocentesis.

In the case of Haemophilus sp beta-lactamase producers, minimal inhibitory concentrations of ampicillin were reduced 8 times by the use of the inhibitor; good results were also obtained for B. catarrhalis.

Haemophilus influenzae, B. catarrhalis together with Streptococcus pneumoniae are recognized as the major pathogens involved in upper respiratory tract infections. The increasing frequency of beta-lactamase producing strains has impaired the use of aminopenicillins.

The combination of an inhibitor and beta-lactam restore the activity of the latter, suggesting that this combination can serve as first choice in therapy.     

Fungistatic Activity of Miconazole against Candida albicans in Relation to pH and Concentration of Nonprotonated Drug

At less than 10(-5) M, miconazole (MCZ) exerts a fungistatic effect on Candida albicans, presumably by interfering with ergosterol biosynthesis. The imidazole moiety of MCZ is subject to protonation (pKa approximately 6.5). Based on pKa and greater water solubility of protonated (MCZH+) versus nonprotonated (MCZo) drug, fungistatic action ought to be markedly affected by environmental pH, but apparently it is not. In this report growth phase, pH, and concentrations of MCZ and MCZo have been studied in relation to fungistasis. Yeasts were grown in a synthetic liquid medium and MCZ effects were monitored by viability determinations. Results showed that fungistatic activity is little affected by growth phase and is largely independent of drug concentration and pH. Antagonism of fungistasis by low pH was demonstrated only at less than 10(-7) M MCZ. Data supported earlier proposals that MCZo is required for biological activity and suggested that target sites are saturated at very low levels of drug.     

Comparative In Vitro Activity of Sparfloxacin (AT 4140, RP 64206 - SPFX) Against 275 Multiresistant Clinical Isolates

The in-vitto activity of sparfloxacin was compared with that of pefloxacin, ofloxacin, ciprofloxacin, imipenem, ceftazidime, gentamicin and amikacin against 275 multiresistant nosocomial clinical isolates. They consisted of Pseudomonas aetuginosa (37), Entetobacter cloacae (42), Acinetobactet anitratus (60), Klebsiella pneumoniae (37) and Staphylococcus sp (99). Minimum inhibitory concentrations (MIC₉₀) and geometric mean MICs for sparfloxacin were as follows (mg/1): P. aeruginosa 128 - 23.7, E. cloacae 1 - 0.13, A. anitratus 2 - 0.14, K. pneumoniae 1 - 0.08, MRSA 16 - 0.98, MSSA 0.12 - 0.03, MRSE 0.25 - 0.12 and MSSE 0.12 - 0.05. It is concluded that sparfloxacin was the most potent agent against staphylococci and A. anitratus including strains resistant to the other quinolones while ciprofloxacin was the most potent agent against P. aeruginosa, E. cloacae and K. pneumoniae.     

Sensitivity of Clinical Yeast Isolates in Kuwait against a Number of Antifungal Agents

Summary: Clinical yeast isolates were taken from 37 patients with presumptive skin candidiasis in Kuwait. In vitro sensitivity tests using amphotericin B, nystatin, miconazole nitrate, 5-fluorocytosine and chlorhexidine were carried out. Amphotericin B was found to be the most effective and 5-fluorocytosine the least.
Zusammenfassung: Von 37 Patienten wurden wegen vermuteter Candida-Mykose Hefen isoliert. In-vitro-Resistenztestungen wurden mit Amphotericin B, Nystatin, Miconazolnitrat, 5-Fluorocytosin und Chlorhexidin ausgeführt. Bei dieser Testung wurde Amphotericin B als die wirksamste und 5-Fluorocytosin als die am wenigsten wirksame Substanz ermittelt.     

Comparative In- Vitro Activity of Fourteen Antibiotics Against Clinical Isolates of Enterococci

Summary

The in-vitto antibacterial activities of fourteen antimicrobial agents, including ampicillin, amikacin, Augmentin, ceftazidime, cefotaxime, ceftriaxone, ciprofloxacin, erythromycin, gentamicin, penicillin G, piperacillin, rifampicin, streptomycin and vancomycin, were compared against 195 enterococcal strains isolated from clinical specimens received at the King Abdulaziz University Hospital in Saudi Arabia. The antibacterial susceptibility was determined by the minimal inhibitory concentration (MIC) using an agar dilution method. Ampicillin, Augmentin and vancomycin exhibited the greatest activity, inhibiting 90% of the tested strains (MIC90) at 2 μg/ml, followed by penicillin G and piperacillin with MIC90 of 4 μg/ml. Erythromycin, third generation cephalosporins, aminoglycosides and rifampicin, on the other hand, had poor activity against enterococci with MIC90s well above the obtainable serum concentrations. The clinical implications of resistance to aminoglycosides and the alternative antimicrobial therapy in serious entrococcal infections are discussed in the text.     

In vitro Efficacy of Anti-glial Fibrillary Acidic Protein Monoclonal Antibodies against Human Malignant Glioma Cell Lines

Our studies have confirmed the presence of large concentrations of various intermediate filament proteins (IFPs) in glioma tissue compared to normal brain. This avenue of research was extended to assess the anti-proliferative activity of anti-intermediate filament protein monoclonal antibodies (anti-IFP mAbs)against human glioma cells. In this study, anti-proliferative activity of glial fibrillary acidic protein monoclonal antibodies (anti-GFAP mAbs) has been tested in vitro, using glioma cell lines prepared and established from freshly resected brain tumors. One anaplastic astrocytoma (AA), two glioblastoma multiforme (GB₁ and GB₂) cell lines and three anti-GFAP mAbs (Bi₂C₄, B₁₂B₄ and B₆C₆, all IgG₁₅, kappa) were used. Immunofiuorescence study indicated the ability of anti-GFAP mAbs to recognize the cell surface of glioma cells and the inhibition study showed that mAb B₁₂B₄ inhibited the proliferation of GB¹, (96%), GB₂(85%)and AA(93%) at a concentration of 3.2x 10^?10M. mAb B₁₂C₄ inhibited the proliferation of GB₁ (95%), GB₂ (86%) and A A (91%) at a concentration of 3.26 X10-¹⁰M and mAb B₆C₅ inhibited the proliferation of GB₁ (75%), GB₂ (75%) and AA (91%) at a concentration of 2.074 X10 ^?19M. Thymidine release assay demonstrated the cytolytic activities of anti-GFAP mAbs towards these glioma cell lines, and this observation was confirmed by dye exclusion, which indicated the lysis of glioma cells after anti-GFAP mAbs treatment. Anti-GFAP mAbs had little effect (<120%) on normal human lymphocyte, liver and intestine cell lines. These results look promising for radioimaging and immunotherapy of human gliomas.     

Discovery of Fully Human Anti-MET Monoclonal Antibodies with Antitumor Activity against Colon Cancer Tumor Models In Vivo

The receptor tyrosine kinase MET is a major component controlling the invasive growth program in embryonic development and in invasive malignancies. The discovery of therapeutic antibodies against MET has been difficult, and antibodies that compete with hepatocyte growth factor (HGF) act as agonists. By applying phage technology and cell-based panning strategies, we discovered two fully human antibodies against MET (R13 and R28), which synergistically inhibit HGF binding to MET and elicit antibody-dependent cellular cytotoxicity. Cell-based phosphorylation assays demonstrate that R13 and R28 abrogate HGF-induced activation of MET, AKT1, ERK1/2, and HGF-induced migration and proliferation. FACS experiments suggest that the inhibitory effect is mediated by “locking” MET receptor in a state with R13, which then increases avidity of R28 for the extracellular domain of MET, thus blocking HGF binding without activating the receptor. In vivo studies demonstrate that the combination of R13/28 significantly inhibited tumor growth in various colon tumor xenograft models. Inhibition of tumor growth was associated with induction of hypoxia. Global gene expression analysis shows that inhibition of HGF/MET pathway significantly upregulated the tumor suppressors KLF6, CEACAM1, and BMP2, the negative regulator of phosphatidylinositol-3-OH-kinase PIK3IP1, and significantly suppressed SCF and SERPINE2, both enhancers of proliferation and invasiveness. Moreover, in an experimental metastasis model, R13/28 increased survival by preventing the recurrence of otherwise lethal lung metastases. Taken together, these results underscore the utility of a dual-antibody approach for targeting MET and possibly other receptor tyrosine kinases. Our approach could be expanded to drug discovery efforts against other cell surface proteins.     

In- Vitro Activity of Ciprofloxacin and Sixteen Other Antimicrobial Agents against Blood Culture Isolates

Summary

The in-vitro antibacterial activities of seventeen antimicrobial agents including ampicillin, amikacin, Augmentin, aztreonam, cefazolin, cefuroxime, cefotaxime, ceftizoxime, ceftriaxone, ciprofloxacin, cloxacillin, erythromycin, gentamicin, penicillin G, piperacillin and vancomycin were compared against 100 Gram-negative and Gram-positive strains isolated from blood culture specimens received at the King Abdulaziz University Hospital (KAUH), in Jeddah, Saudi Arabia.

The antibacterial susceptibility was determined by the minimal inhibitory concentration (MIC), using an agar dilution method. Ciprofloxacin exhibited the greatest activity, inhibiting 90% of the tested strains (MIC₉₀) at a concentration ranging from < 0.015-0.5 mg/L. Against cloxacillin resistant or susceptible strains of Staphylococcus aureus and coagulase-negative staphylococci, ciprofloxacin had similar activity with MIC₉₀, of 0.2 mg/L. Salmonella typhi and salmonella species which were resistant to ampicillin and augmentin remained sensitive to ciprofloxacin (Mid₉₀ < 0.015-0.125) mg/L.). Against gentamicin sensitive and resistant Pseudomonas aeruginosa and Pseudomonas species, ciprofloxacin MIC₉₀ was 0.5 and 1 mg/L respectively. Aminoglycosides, third generation cephalosporins, aztreonam and antipseudomonal penicillins, on the other hand, showed high MIC₉₀ well above the obtainable serum concentrations against Enterobacteriaceae and Pseudomonas species.     

In Vitro and In Vivo Anticancer Activity of Gimatecan against Hepatocellular Carcinoma

Objective: Gimatecan is a new camptothecin (CPT) analogue that inhibits tumor growth by targeting DNA topoisomerase I (TOP I) and introducing strong and persistent DNA cleavage. Anti-tumor activity has been demonstrated with a wide range of solid tumors in previous preclinical and clinical studies. Here, we investigated for the first time the effects of gimatecan on the proliferation of hepatocellular carcinoma (HCC) cells both in vitro and in vivo. Methods: Anticancer efficacy of gimatecan were evaluated in a panel of HCC cell lines and corresponding mouse xenograft models. Inhibition of cell proliferation was measured by CellTiter-Glo cell viability assay. In vivo, gimatecan and control preparations were orally administered every four days, for a total of four times. Tumor volume and body weights of the mice were measured twice weekly. Results: In vitro cytotoxicity evaluation showed that gimatecan inhibited the proliferation of a large panel of HCC cell lines in a dose dependent manner, with IC50 values ranging between 12.1~1085.0 nM. In vivo evaluation in mouse xenograft models showed significant antitumor effects of gimatecan at 0.8mg/kg and 0.4mg/kg as compared to the control group. Conclusion: This study suggested that gimatecan may have the potential to be used as a chemotherapeutic agent for the treatment of HCC.