Post-Antibiotic Effect of Levofloxacin and Tobramycin Alone or in Combination with Cefepime against Pseudomonas aeruginosa

Background: Levofloxacin and tobramycin, alone and in combination with cefepime, were investigated for their in vitro activities and post-antibiotic effects (PAEs) on Pseudomonas aeruginosa. Methods: The in vitro activities of tobramycin and levofloxacin in combination with cefepime were determined by microbroth chequerboard technique against six P. aeruginosa strains that were isolated from patients with bacteremia. The results were interpreted by fractional inhibitory concentration index. To determine the PAEs, P. aeruginosa strains in the logarithmic phase of growth were exposed for 1 h to antibiotics, alone and in combination. Recovery periods of test cultures were evaluated using viable counting after centrifugation. Results: Three synergistic interactions were observed with cefepime-tobramycin and one with cefepime-levofloxacin combinations against tested strains. No antagonism was observed. Levofloxacin produced a PAE ranging from 1.9 to 4.5 h in a concentration-dependent manner. Similar PAEs were induced by tobramycin (ranging from 1.5 to 3.1 h). However, negative PAE values were obtained with cefepime. In combination, cefepime slightly reduced the PAE of tobramycin and levofloxacin against studied strains. Conclusion: The finding of this study may have important clinical implications for the timing of doses during therapy with cefepime, levofloxacin and tobramycin alone and in combination. Copyright (C) 2009 S. Karger AG, Base

Investigation of preservative efficacy and microbiological content of some cosmetics found on the market.

In this study, microbial content and preservative efficacy of various cosmetic products, which are produced and sold in markets of our country, were investigated. Microbial content and preservative efficacies of products were investigated according to United States Pharmacopeia (USP) method. Microorganism counts of out 14 of 93 cosmetic products were recovered in the range between 1.5 x 10(2)-5.5 x 10(5) cfu/ml. Staphylococcus aureus was the most common contaminant identified in samples (from six different products) and was followed by Burkholderia cepacia (from four different products). Gram negative organisms, including Pseudomonas aeruginosa and a yeast Candida krusei, were also isolated from samples. Escherichia coli and Salmonella sp. were not recovered, any of samples. Preservative efficacies of fourteen out of ninety-three products did not meet the general efficacy of antimicrobial preservation criteria of the USP. Among these fourteen products, degradation and color change by Aspergillus niger was observed in one of samples. According to results, it was observed that pathogen and potential pathogen microorganisms can be found in unused cosmetic products and also preservatives may be ineffective in preventing them. Thus, in order to prevent the contamination that can occur during production, manufacturers are required to manufacture products in compliance with wholesome manufacturing practices and, considering consumer health, it is necessary to add an effective preservative as determined by regulations

Antimicrobial activities of widely consumed herbal teas, alone or in combination with antibiotics: an in vitro study

Background. Because of increasing antibiotic resistance, herbal teas are the most popular natural alternatives for the treatment of infectious diseases, and are currently gaining more importance. We examined the antimicrobial activities of 31 herbal teas both alone and in combination with antibiotics or antifungals against some standard and clinical isolates of Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis, methicillin susceptible/resistant Staphylococcus aureus and Candida albicans

Antimicrobial activities of widely consumed herbal teas, alone or in combination with antibiotics: an in vitro study

Background Because of increasing antibiotic resistance, herbal teas are the most popular natural alternatives for the treatment of infectious diseases, and are currently gaining more importance. We examined the antimicrobial activities of 31 herbal teas both alone and in combination with antibiotics or antifungals against some standard and clinical isolates of Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis, methicillin susceptible/resistant Staphylococcus aureus and Candida albicans. Methods The antimicrobial activities of the teas were determined by using the disk diffusion and microbroth dilution methods, and the combination studies were examined by using the microbroth checkerboard and the time killing curve methods. Results Rosehip, rosehip bag, pomegranate blossom, thyme, wormwood, mint, echinacea bag, cinnamon, black, and green teas were active against most of the studied microorganisms. In the combination studies, we characterized all the expected effects (synergistic, additive, and antagonistic) between the teas and the antimicrobials. While synergy was observed more frequently between ampicillin, ampicillin-sulbactam, or nystatine, and the various tea combinations, most of the effects between the ciprofloxacin, erythromycin, cefuroxime, or amikacin and various tea combinations, particularly rosehip, rosehip bag, and pomegranate blossom teas, were antagonistic. The results of the time kill curve analyses showed that none of the herbal teas were bactericidal in their usage concentrations; however, in combination with antibiotics they showed some bactericidal effect. Discussion Some herbal teas, particularly rosehip and pomegranate blossom should be avoided because of their antagonistic interactions with some antibiotics during the course of antibiotic treatment or they should be consumed alone for their antimicrobial activities

In vitro activities of antifungals alone and in combination with tigecycline against Candida albicans biofilms

Background. Candida may form biofilms, which are thought to underlie the most recalcitrant infections

In vitro activities of antifungals alone and in combination with tigecycline against Candida albicans biofilms

WOS: 000439944000005PubMed ID: 30065873Background. Candida may form biofilms, which are thought to underlie the most recalcitrant infections. Methods. In this study, activities of antifungal agents alone and in combination with tigecycline against planktonic cells and mature and developing biofilms of Candida albicans isolates were evaluated. Results. Amphotericin B and echinocandins were found to be the most effective agents against mature biofilms, whereas the least effective agent was fluconazole. Furthermore, the most effective anti-fungal monotherapies against biofilm formation were amphotericin B and anidulafungin, and the least effective monotherapy was itraconazole. The combination of tigecycline and amphotericin B yielded synergistic effects, whereas combinations containing itraconazole yielded antagonist effects against planktonic cells. The combination of tigecycline and caspofungin exhibited maximum efficacy against mature biofilms, whereas combinations containing itraconazole exhibited minimal effects. Combinations of tigecycline with amphotericin B or anidulafungin were highly effective against C. albicans biofllm formation. Discussion. In summary, tigecycline was highly active against C. albicans particularly when combined with amphotericin B and echinocandins.Research Fund of Istanbul University [32917]This work was supported by the Research Fund of Istanbul University (project number 32917). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Synthesis, characterization and biological evaluation of 1,3-thiazolidine-4-ones derived from (2S)-2-benzoylamino-3-methylbutanohydrazide hydrazones

Novel 2-aryl-5-non-substituted / methyl-1,3-thiazolidine-4-one derivatives 14-33 carrying L-valine core were synthesized by the reaction of acylhydrazones 4-13 with thioglycolic acid / thiolactic acid. Structures of all synthesized compounds 14-33 were confirmed by IR, H-1-NMR and HR-MS analysis and C-13-NMR were recorded for selected compounds 17, 21, 28 and 30. None of the compounds 14-33 showed activity against HIV-1 (strain IIIB) or HIV-2 (strain ROD) in an MT-4/MTT based assay. Compounds 14-33 were also screened against Feline Corona Virus (FIPV), Feline Herpes Virus, HSV-1(KOS), HSV-1 (TK-KOS ACVr), HSV-2 (G), Vaccinia virus, Vesicular stomatitis virus, Cytomegalovirus, Varicella-Zoster virus, Respiratory syncytial virus, Coxsackie B4 virus, Parainfluenza-3 virus, Reovirus-1, Sindbis virus and Punta Toro virus, but none of them showed antiviral activity at subtoxic concentrations. Anti-HCV NS5B RdRp activity of some selected compounds from the series 14-33 were found to vary between 4.1-27 % at the concentration of 100 mu M. In vitro antibacterial activity evaluation of selected compounds 16-23 and 25-32, against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Enterococcus faecalis ATCC 29212, Klebsiella pneumoniae ATCC 4352, Bacillus subtilis ATCC 6633, Staphylococcus epidermidis ATCC 12228, MRSA and antifungal activity against Candida albicans ATCC 10231 resulted in the MIC values between 625->5000 mu g/ml