Comparative Evaluation of Polyphenol Contents and Biological Activities of Five Cistus L. Species Native to Turkey.

In this study phytochemical compounds and antioxidant capacity, cytotoxic, antimicrobial and anti-biofilm activities of hydroethanolic extracts of five Cistus species (C. creticus L., C. laurifolius L., C. monspeliensis L., C. parviflorus Lam. and C. salviifolius L.) distributed in Turkey were investigated. (+)-catechin, epigallocatechin gallate, quercetin-3-O-rutinoside, quercetin-3-O-glucoside, kaempferol-3-O-glucoside, luteolin were detected in different amounts. Strongest antioxidant capacities were observed with C. creticus, and C. parvifolius (0.476 and 0.452, respectively). Minimum inhibitory concentrations (MIC) of the extracts were determined between 32 and 128 µg/mL against different bacteria and Candida strains. C. monspeliensis and C. laurifolius extracts were inhibited the biofilm production levels of three Gram-negative bacteria (E. coli, S. enterica, P. aeruginosa), two Gram-positive bacteria (S. aureus, B. subtilis) and three Candida strains (C. albicans, C. parapsilosis, C. krusei). C. creticus extract showed strongest cytotoxic activity against human breast adenocarcinoma (MCF-7) and prostate cell lines (PC-3) (IC50 : 14.04±2.78 µg/mL and 34.04±2.74 µg/mL, respectively) among all plants tested.

Development of antimicrobial nanocomposite scaffolds via loading CZTSe quantum dots for wound dressing applications.

The antimicrobial properties of scaffolds designed for use in wound healing are accepted as an important factor in the healing process to accelerate the wound healing process without causing inflammation. For this purpose, chitosan-polyvinyl alcohol composite membranes loaded with Cu2ZnSnSe4quantum dots (CZTSe QDs) as an antibacterial and cytocompatible biomaterial to regulate the wound healing process were produced. CZTSe QDs particles were synthesized under hydrothermal conditions. Polymer-based nanocomposites with different concentrations of the synthesized nanoparticles were produced by the solvent casting method. After detailed physicochemical and morphological characterizations of CZTSe QDs and composite membranes, antibacterial activities and cell viability were extensively investigated against gram-positive and gram-negative bacterial and yeast strains, and L929 mouse fibroblast cells lines, respectively. The results show that the preparation of composite scaffolds at a QDs concentration of 3.3% by weight has the best antimicrobial activity. Composite scaffold membranes, which can be obtained as a result of an easy production process, are thought to have great potential applications in tissue engineering as wound dressing material due to their high mechanical properties, wettability, strong antibacterial properties and non-toxicity.

Chitosan-bovine serum albumin-Carbopol 940 nanogels for mupirocin dermal delivery: ex-vivo permeation and evaluation of cellular binding capacity via radiolabeling.

The goal of this study was to develop and examine the nanogel-based topical delivery system of mupirocin. Nanogels were prepared with chitosan and bovine serum albumin by ionic gelation and Carbopol 940 was added to improve the gelling/adhesive properties. Detailed characterization studies were performed and the cellular binding capacity of radiolabeled nanogels was investigated on CCD-1070Sk cell lines. Results indicate the successful formation of nanogels with particle size and zeta potential ranged between 341.920-603.320 nm and 13.120-24.300 mV, respectively. The mechanical and rheological studies proved pseudoplastic and strong elastic gel behavior (G' > G''). Mupirocin was successfully entrapped into nanogels with a ratio of more than 95% and the loaded drug was slowly released up to 93.89 ± 3.07% within 24 h. The ex vivo penetration and permeation percentages of mupirocin were very low (1.172 ± 0.202% and 0.161 ± 0.136%) indicating the suitability of nanogels for dermal use against superficial skin infections. The microbiological studies pointed out the effectiveness of nanogels against Staphylococcus aureus strains. Nanogels did not show toxicity signs and the cell binding capacity of radiolabeled formulations was found to be higher than [99mTc]NaTcO4 to CCD-1070Sk cell line. Overall, mupirocin nanogels might be considered as a potential and safe topical treatment option for bacterial skin infections.

Nonsteroidal antiinflammatory drugs alter antibiotic susceptibility and expression of virulence-related genes and protein A of Staphylococcus aureus

Background/aim: Nonsteroidal antiinflammatory drugs (NSAIDs) including diclofenac, naproxen, ibuprofen, acetylsalicylic acid, and acetaminophen have been shown to have antimicrobial effects on various microorganisms. The aim of this study was to investigate the antibacterial effects of NSAIDs on Staphylococcus aureus. Materials and methods: Susceptibilities of S. aureus strains to NSAIDs with or without antimicrobials (moxifloxacin, vancomycin, ciprofloxacin, clindamycin, and gentamicin) were determined using the microdilution method and disk diffusion test. Expression levels of genes in the presence of drugs were investigated by real-time quantitative RT-PCR (qRT-PCR), and immunoblotting analysis was performed for staphylococcal protein A (SpA). Results: Our results showed that all NSAIDs were active against S. aureus strains with MIC values ranging from 195 µg/mL to 6250 µg/ mL. NSAIDs increased the antibiotic susceptibility of the strains, and diclofenac was found to be more effective than the other drugs. Drugs showed different effects on expression levels of virulence factor and/or regulatory genes. Immunoblotting analysis of SpA protein was mostly in accordance with qRT-PCR results. Conclusion: The regulatory/virulence factor genes and proteins of S. aureus investigated in this study may be reasonable targets for these drugs, and we suggest that the data may contribute to the field of infection control and antimicrobial resistance.

Effects of disinfectants and ciprofloxacin on quorum sensing genes and biofilm of clinical Pseudomonas aeruginosa isolates.

BACKGROUND: Pseudomonas aeruginosa is one of the most virulent bacteria and quorum sensing (QS) genes have an importance on virulence factors such as biofilm that provide resistance against disinfectants and antibiotics. OBJECTIVE: This study aimed to determine the minimum inhibitory concentrations of the disinfectants, to investigate the effects of disinfectants and ciprofloxacin on biofilm production mature biofilm of clinical P. aeruginosa isolates, and it was aimed to investigate the effects of the agents on the expression levels of several QS-related genes in the isolates. METHODS: Minimum inhibitory concentration (MIC) levels of polyhexamethylene biguanide (PHMB), chlorhexidine (CHX), quaternary ammonium compounds (QAC), glutaraldehyde (GLU) and ciprofloxacin (CIP) against clinical P. aeruginosa isolates were evaluated by microdilution method. Effects of the agents on the biofilm producing capacities of clonally unrelated nine strains were investigated by spectrophotometric method. Alterations in the expression of QS-related genes (lasI, lasR, rhlI and rhlR) were investigated by qPCR in three isolates that were CIP-susceptible and strong biofilm producer. RESULTS: According to microdilution method results, three isolates were found as resistant, one isolate was found as intermediate susceptible and five isolates were found as susceptible to CIP, and CHX (7.81-31.25 µg/mL) had the lowest MIC against P. aeruginosa. CHX inhibited biofilm production levels of eight of nine isolates, and GLU and CIP inhibited six of nine isolates in the presence of agents at MIC levels. GLU inhibited the mature biofilm levels of three of nine isolates at MIC and MIC/4 levels and four of nine isolates at MIC/2 levels. Expression levels of QS-related genes were reduced or induced in the presence of different disinfectants. CONCLUSIONS: More efforts are required to decrease the risk of ineffective and low-dose application of disinfectants and antimicrobials against bacteria. Targeting of QS-related genes may be a reasonable strategy for the inhibition of virulence factors in P. aeruginosa.

Antifungal photodynamic activities of phthalocyanine derivatives on Candida albicans.

Antimicrobial resistance is one of the most important causes of morbidity and mortality in the treatment of infectious diseases worldwide. Candida albicans is one of the most virulent and common species of fungi to cause invasive fungal infections on humans. Alternative treatment strategies, including photodynamic therapy, are needed for controlling these infectious diseases. The aim of this study was to investigate the antifungal photodynamic activities of phthalocyanine derivatives on C. albicans. The minimum inhibitory concentration (MIC) values of compounds were determined by the broth microdilution method. Uptake of the compounds in C. albicans and dark toxicity of the compounds were also investigated. Photodynamic inhibition of growth experiments was performed by measuring the colony-forming unit/mL (CFU/mL) of the strain. Maximum uptake into the cells was observed in the presence of 64 µg/mL concentration for each compound except for ZnPc. Compounds did not show dark toxicity/inhibitory effects at sub-MIC concentrations on C. albicans when compared to the negative control groups. Zn(II)Pc, ZnPc, and ZnPc-TiO2 showed fungicidal effect after irradiation with the light dose of 90 J/cm2 in the presence of the compounds. In addition to the fungicidal effects, SubPc, SubPc-TiO2, Es-SiPc, and Es-SubPc compounds were also found to have inhibitory effects on the growth of yeast cells after irradiation.

Synthesis of new water-soluble ionic liquids and their antibacterial profile against gram-positive and gram-negative bacteria.

A series of imidazolium bromide salts (NIM-Br 1a, 1b and 1c) bearing different lengths of alkyl chains were synthesized and theirin vitro antibacterial activities were determined by measuring the minimum inhibitory concentration (MIC) values for Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Enterococcus faecalis. In addition, these imidazolium derivatives were also evaluated against biofilm produced by these bacterial strains. All compounds were found to be effective against Gram-positive and Gram-negative bacteria, and also more effective on the S. aureus biofilm production than the others.

Quercetin inhibits swarming motility and activates biofilm production of Proteus mirabilis possibly by interacting with central regulators, metabolic status or active pump proteins.

BACKGROUND: Via its virulence factors such as swarm differentiation, biofilm and hemolysin production, urease enzyme, Proteus mirabilis causes urinary tract infections (UTIs), especially in complicated cases. Anti-pathogenic compounds attenuate the virulence of bacteria without showing 'cidal' activity and carry the potential to be used in the prevention and treatment of infectious diseases. PURPOSE: Search for anti-pathogenic effects of quercetin, which is a widely known and biologically active phytochemical, on Proteus mirabilis was the purpose of this study. In this context, the potential inhibitory activity of quercetin on swarming motility and biofilm production of a wild-type strain, P. mirabilis HI4320, was investigated in both phenotypically and genotypically. METHODS: Quercetin's effect on swarming motility was examined on LB agar plates, containing quercetin at various concentrations, by measuring the swarming diameter. The effect on biofilm formation, on the other hand, was analyzed by staining the formed biofilm of the bacterium, exposed to quercetin at various concentrations, with crystal violet and reading spectrophotometrically. Differences in expression levels of selected genes involved in swarming regulation were determined by real-time reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) to evaluate the mechanism of inhibitory action on swarming. Further investigations were carried out repeating swarming assays with the clones that derived from the wild-type strain by a TA system kit for direct one-step cloning and overexpressing the relevant genes. RESULTS: Our study revealed that quercetin inhibited swarming motility while activating biofilm production of P. mirabilis in direct proportion to the dose. Although all selected genes are inhibited in the same manner in liquid medium, and no significant differences could be detected in solid medium as demonstrated by RT-qPCR, experiments repeated with the clones overexpressing flhC (a component of flagellar transcriptional activator), speB (an agmatinase enzyme) and ompF (an outer membrane porin) genes showed that the respective clones could restore swarming, compensating for the inhibitory effect of quercetin. CONCLUSION: Quercetin's inhibitory effect on P. mirabilis swarming was possibly due to interactions with components of swarming regulators, the genes expressing polyamine coding enzymes that trigger swarm differentiation, or active pump proteins.

Analyses of Plasmids Harbouring Quinolone Resistance Determinants in Enterobacteriaceae Members.

The aim of this study was to explore the plasmid characteristics of eight clinical Enterobacteriaceae strains containing extended broad spectrum beta-lactamases and plasmid-mediated quinolone resistance. Plasmids were transferred by conjugation or transformation and resistance determinants were investigated by PCR. We showed that at least one plasmid harbouring qnrB or qnrS determinant was transferred by conjugation in five isolates. QepA determinant was confirmed to be on a non-conjugative plasmid. We found at least one beta-lactamase gene in seven of the eight clinical isolates having plasmid-mediated quinolone resistance, which indicated that these two resistance determinants were mostly on the same conjugative plasmids.

[Investigation of the virulence factors of multidrug-resistant Acinetobacter baumannii isolates]. / Çok ilaca dirençli Acinetobacter baumannii izolatlarinda virülans faktörlerinin arastirilmasi

Acinetobacter baumannii is an opportunistic human pathogen which causes life-threatening nosocomial infections such as ventilator-associated pneumonia, bacteremia, meningitis, urinary tract and wound infections. Treatment options are very limited for infections caused by multi-drug resistant (MDR) A.baumannii strains. Until recently, the majority of studies related to A.baumannii have focused on antibiotic resistance, treatment protocols and epidemiological data, however, there have been few studies addressing the virulence factors of this organism. The features such as biofilm formation, serum resistance, motility, efflux pumps and iron acquisition mechanisms help the bacterium to survive in adverse environmental conditions and facilitate the development of an infection. The aim of the present study was to investigate the basic characteristics that contribute to the virulence of clinically important MDR A.baumannii isolates. Sixty-five ciprofloxacin-imipenem-trimethoprim/sulfamethoxazole-resistant A.baumannii strains isolated from various clinical specimens between December 2011 and March 2012 at Ege University Faculty of Medicine, Department of Medical Microbiology were included in the study. The clonal relationship of the isolates was analyzed by PCR using Enterobacterial repetitive intergenic consensus (ERIC)-2 primer. Biofilm formation, serum resistance, twitching and swarming motility, efflux pump and siderophore production were sought in representatives of each clone. Investigated MDR A.baumannii isolates were classified into seven main clusters, and the largest cluster included 86% of the strains. The virulence-associated features were investigated in 16 representative strains, including sub-groups. Twelve, three and one of the examined strains were determined to be strong, intermediate and weak biofilm producers, respectively. Siderophore production was not encountered in any of the isolates. Of the sixteen strains, two, one and thirteen isolates were found to be resistant, moderately susceptible and susceptible to bactericidal effect of serum, respectively. In our study, swarming motility was observed in seven strains while twitching motility was observed in only one strain. Swarming was simultaneously detected with twitching in one isolate. The presence of an efflux pump was investigated with ciprofloxacin in 16 representative strains but none of them were positive. However, eflux pump was determined in two of the five doxycycline resistant strains. Biofilm production was the most commonly observed characteristic among the examined strains. In addition, serum resistance, swarming and an efflux pump which has a spectrum including tetracyclines, were also determined among features associated with virulence. While the biofilm production was encountered at the members of all clones, serum resistance was found only in the representatives of the most dominant clone. Motility and the presence of an efflux pump were not associated with a particular clone. MDR A.baumannii strains are among the most important agents of nosocomial infections in our hospital and all over the world. Revealing the characteristics that play a role in the pathogenesis of these isolates, will contribute to infection control measures and to the investigation of new treatment options.

Protective effects of ascorbic acid on hepatotoxicity and oxidative stress caused by carbon tetrachloride in the liver of Wistar rats.

This study was planned to investigate the protective effect of l(+)-ascorbic acid (Vit C) on CCl(4)-induced hepatotoxicity and oxidative stress in the liver of Wistar rats (Rattus Norvegicus, strain Wistar). Twenty-four adult male Wistar rats were fed with standard rat chow diet for 10 days and randomly were divided into four groups of six each as follows: (1) control, (2) CCl(4), (3) "CCl(4) + Vit C", (4) Vit C groups. CCl(4) was applied to rats belonging to CCl(4) and "CCl(4) + Vit C" groups subcutaneously at 1 mg kg(-1) dose CCl(4) for 3 days. Vit C applied to "CCl(4) + Vit C" and "Vit C" group rats intraperitoneally at 300 mg kg(-1) dose for 3 days. All rats were sacrificed and livers were quickly removed on the fourth day of the experiment. MDA, total glutathione (T.GSH) levels and superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX) activities were measured in the liver of all groups of rats and also serum alanine amino transferase (ALT) and aspartate amino transferase (AST) activities were detected to determine liver functions in all groups of rats. Histopathological changes were evaluated by light and transmission electron microscopes. In "CCl(4) + Vit C" group, MDA level was significantly decreased (p < 0.05) and SOD, CAT, GSH-PX activities were significantly increased (p < 0.005, 0.01, 0.05) respectively, T.GSH level was significantly increased (p < 0.005) and serum ALT and AST activities were significantly decreased (p < 0.01, 0.05), respectively, when compared with CCl(4) group. These results show that Vit C has a highly protective effect on hepatotoxicity and oxidative stress caused by CCl(4).

Comparison of chemopreventive effects of Vitamin E plus selenium versus melatonin in 7,12-dimethylbenz(a)anthracene-induced mouse brain damage.

In this work, the protective effect of Vitamin E plus selenium (Vit E+Se) and melatonin against 7,12-dimethylbenz(a)anthracene (7,12-DMBA)-induced changes in superoxide dismutase (SOD), glutathione peroxidase (GSHPx), catalase (CAT) and carbonic anhydrase (CA) activities and malonedialdehyde (MDA) levels of mouse brain were compared. 12-month old mice were divided into four groups each including 10 animals. The first group served as control group. The second group was treated with 7,12-DMBA (20 mg/(kg day)). The third group was treated with 7,12-DMBA and Vitamin E (90 microg/(individual day)) and selenium (1.8 microg/(individual day)) simultaneously. The fourth group was treated with 7,12-DMBA and melatonin (4.2 mg/(kg day)) simultaneously. Treatment continued for 21 days after which the mice were sacrificed and brain homogenates were prepared. 7,12-DMBA treated group exhibited significantly decreased levels of brain SOD, GSHPx, CAT and CA activities and increased MDA levels as compared to control. Vitamin E+Se fully or partially restored enzyme inhibition except for SOD. Lipid peroxidation was also reduced in Vitamin E+Se treated group. Melatonin provided a better protection for SOD, GSHPx and CAT, and a plausible protection for CA activity. Protection against lipid peroxidation measured as MDA in melatonin treated group was appreciable although slightly lesser than the protection provided by Vitamin E+Se. The results imply that Vitamin E+Se and melatonin both provide chemoprevention against 7,12-DMBA-induced oxidative stress in mouse brain.