Screening of quinolone antibiotic residues in chicken meat and beef sold in the markets of Ankara, Turkey.

This study aimed to find the effects of quinolone antibiotics in chicken and beef used in Ankara, Turkey. Total number of 127 chicken and 104 beef meat samples were collected randomly from local markets for analysis. Extraction and determination of quinolones were made by ELISA procedure. One hundred eighteen of 231 (51.1%) examined chicken meat and beef samples were found to contain quinolone antibiotic residue. Among the chicken meat and beef samples, 58 (45.7%) of chicken meat samples and 60 (57.7%) of beef meat samples were positive for quinolones, respectively. The mean levels (±SE) of quinolones were found to be 30.81 ± 0.45 µg/kg and 6.64 ± 1.11 µg/kg in chicken and beef samples, respectively. This study indicated that some chicken and beef meat sold in Ankara contains residues of quinolone antibiotics.

Candida albicans and Pseudomonas aeruginosa adhesion on soft contact lenses.

BACKGROUND: In this study it was aimed to determine the adherence of Pseudomonas and Candida to contact lens surfaces, and to determine the difference in adherence between five contact lens types. Biofilm-negative control strains were also used to emphasize the difference between biofilm-positive and biofilm-negative strains in adherence. METHODS: Five different soft contact lenses were used to investigate the adherence of Pseudomonas aeruginosa and Candida albicans strains. P. aeruginosa ATCC 27853, P. aeruginosa ATCC 10145, C.albicans ATCC 10231 standard strains and C. albicans clinical isolate were included in the study. Slime formation was investigated by two methods; modified Christensen macrotube method, and a modified microtiter plate test. P. aeruginosa and C. albicans slime formation on soft contact lenses was studied in adherence and separation phases. Pseudomonas and Candida suspensions were serially diluted and inoculated to blood agar and sabouraud dextrose agar surfaces respectively. After overnight incubation, the colonies were counted. Sterile unworn contact lenses were used as negative controls, and bacterial and fungal culture suspensions were used as positive controls. The experiments were conducted in three parallel series. RESULTS: The number of adherent Pseudomonas was as follows from high to low in polymacon, etafilcon A, hilafilcon, ocufilcon and lotrafilcon contact lenses respectively. However, the number of adherent yeast were determined higher in lotrafilcon and ocufilcon contact lenses, followed by hilafilcon, etafilcon A and polymacon contact lenses. Biofilm-negative Pseudomonas ATCC standard strain and Candida clinical isolate were used to confirm that the number of adherent cells were lower than the biofilm-positive ones. CONCLUSIONS: This study demonstrates that in addition to the contact lens properties, the microorganisms themselves and their interactions with the lens material also play an important role in adherence.

[Comparison of two different methods for the investigation of in vitro susceptibilities of planktonic and biofilm forming Candida species to antifungal agents]. / Candida türlerinin biyofilm olusturan ve planktonik formlarinin antifungal ajanlara karsi in vitro duyarliliklarinin arastirilmasinda iki farkli yöntemin karsilastirilmasi

Microdilution method that determines the minimum inhibitory concentrations (MIC) of antifungal agents against Candida spp. is still the only method used in laboratories for both biofilm and planktonic forms. However, it was determined in several studies that there were susceptibility differences between the biofilm and planktonic forms of the same microorganism. The aims of this study were the determination of in vitro susceptibilities of planktonic and biofilm forms of Candida strains against antifungal agents, the comparison of the data obtained from planktonic and biofilm forms and the evaluation of two different methods used for the detection of susceptibilities of biofilm forms. Candida albicans ATCC 10231, Candida parapsilosis ATCC 90028 and Candida krusei ATCC 6258 were used as reference strains together with clinical isolates of one of each C.albicans, C.parapsilosis and Candida tropicalis. Microdilution method was used to determine the susceptibilities of planktonic forms of the strains according to CLSI M27-A3 standards, and MIC values of fluconazole, itraconazole, flucytosine, amphotericin B and nystatin were determined. For the detection of antifungal susceptibilities of Candida spp. biofilm forms, Calgary biofilm method (CBM) and BioTimer assay (BTA) were used, and minimum biofilm eradication concentration (MBEC) and minimum biofilm inhibition concentration (MBIC) values of the same antifungals were determined. The difference between MIC and CBM-MBEC, CBM-MBEC and BTA-MBEC, CBM-MBEC and BTAMBIC values were found statistically significant (p < 0.05). In general CBM-MBEC values were found to be higher than MIC values. However, MBEC values were not always very reliable since the exact number of the microorganisms in biofilm can not be determined. BTA-MBIC values were also generally lower than the MBEC values and higher than the MIC values. Statistically significant difference between two methods was determined only for the MBEC values of flucytosine (p= 0.002) and itraconazole (p = 0.025). For flucytosine (p = 0.001) and itraconazole (p = 0.001), there was also a significant difference between CBM-MBEC and BTA-MBIC values, however, the difference was not significant (p > 0.05) for the other antifungal agents. These findings supported that antifungal susceptibilities of biofilm forming Candida strains should also be investigated. However, MBEC and MBIC of the antifungal agents should not always be expected to be higher than the MIC values since the mechanism of action of the specific antifungal agents and the first inoculum concentration of the microorganisms might differ.

Fluconazole release from hydrogels including acrylamide-acrylic acid-itaconic acid, and their microbiological interactions.

Polyacrylamide (PAAm), polyacrylic acid (PAA), poly(acrylamide-co-itaconic acid) (PAAmIA) and poly(acrylic acid-co-itaconic acid) (PAAIA) hydrogels were prepared via free-radical polymerization using ethylene glycol dimethacrylate (EGDMA) as cross-linker. The variations of swelling percentages with time and pH were determined for these hydrogels at 37 degrees C. PAAmIA was found as the most swollen hydrogel at pH 4.0. SEM micrographs were taken to observe the morphology of the hydrogels. The less swollen hydrogel, PAAIA, displays less porosity relative to PAAmIA hydrogel. Fluconazole was entrapped into PAAmIA and PAAIA hydrogels and the release was investigated in Britton-Robinson buffer solution (BR) at pH 4.0 and 37 degrees C. The kinetic release parameters of the hydrogels, n and k, were calculated and Fickian-type diffusion was established for PAAmIA, which releases Fluconazole faster than PAAIA hydrogel. Therapeutic range was reached in the first hour for both hydrogels. Microbiological interactions of hydrogels were also studied in vitro in vaginal medium. It is found that Fluconazole entrapped in hydrogels inhibited the growth of Candida albicans.

Synthesis and biological evaluation of new N-(2-hydroxy-4(or 5)-nitro/aminophenyl)benzamides and phenylacetamides as antimicrobial agents.

A new series of N-(2-hydroxy-4(or 5)-nitro/aminophenyl)benzamide and phenylacetamide derivatives (1a-1n, 2a-2n) were synthesized and evaluated for antibacterial and antifungal activities against Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, and their drug-resistant isolate. Microbiological results indicated that the compounds possessed a broad spectrum of activity against the tested microorganisms at MIC values between 500 and 1.95 microg/ml. Benzamide derivative 1d exhibited the greatest activity with MIC values of 1.95, 3.9, and 7.8 microg/ml against drug-resistant B. subtilis, B. subtilis, and S. aureus, respectively.

Flavonoids with anti-Helicobacter pylori activity from Cistus laurifolius leaves.

Cistus laurifolius flower buds are used traditionally in folk medicine against gastric ailments. In a prior study we showed that the chloroform extract of Cistus laurifolius had a potent anti-ulcer activity. It has been known that there is a causal relationship between peptic ulcer and Helicobacter pylori infection. Then in a previous study, we demonstrated that chloroform extract of Cistus laurifolius possessed a significant anti-Helicobacter pylori activity. We designed this study to isolate and define the active component(s) involved in the anti-Helicobacter pylori activity of the extract through activity-guided fractionation procedures. The chloroform extract was fractionated by using various chromatography techniques, i.e., Sephadex LH-20 column chromatography and preparative thin layer chromatography and six compounds were isolated (1-6). Each of these six compounds' anti-Helicobacter pylori activity was tested in vitro and was measured as minimum inhibition concentration (MIC) values by using agar dilution method. The compound 2 had the highest activity against Helicobacter pylori (MIC 3.9 microg/mL). Its chemical structure was elucidated as quercetin 3-methyl ether (isorhamnetin) by various spectroscopic techniques. We believe that the therapeutic effect of Cistus laurifolius in ulcer is at least partially related to its effect on Helicobacter pylori. We hope that the isolated flavonoid having anti-Helicobacter pylori activity ultimately can be utilized as an alternative or additive agent to the current therapy.

Slime production and proteinase activity of Candida species isolated from blood samples and the comparison of these activities with minimum inhibitory concentration values of antifungal agents.

Slime and proteinase activity of 54 strains consisting of 19 Candida parapsilosis and 35 C. albicans strains isolated from blood samples were investigated in this study. Ketoconazole, amphothericin B, and fluconazole susceptibility of Candida species were compared with slime production and proteinase activity of these species. For both Candida species, no correlation was detected between the slime activity and minimum inhibitory concentration (MIC) values of the three antifungal agents. For both Candida species no correlation was detected between the proteinase activity and the MIC values of amphothericin B, and fluconazole however, statistically significant difference, was determined between the proteinase activity and MIC values of ketoconazole (p = 0.007). Slime production was determined by using modified Christensen macrotube method and proteinase activity was measured by the method of Staib. Antifungal susceptibility was determined through the guidelines of National Committee for Laboratory Standards (NCCLS M27-A).

Slime production and proteinase activity of Candida species isolated from blood samples and the comparison of these activities with minimum inhibitory concentration values of antifungal agents

Slime and proteinase activity of 54 strains consisting of 19 Candida parapsilosis and 35 C. albicans strains isolated from blood samples were investigated in this study. Ketoconazole, amphothericin B, and fluconazole susceptibility of Candida species were compared with slime production and proteinase activity of these species. For both Candida species, no correlation was detected between the slime activity and minimum inhibitory concentration (MIC) values of the three antifungal agents. For both Candida species no correlation was detected between the proteinase activity and the MIC values of amphothericin B, and fluconazole however, statistically significant difference, was determined between the proteinase activity and MIC values of ketoconazole (p = 0.007). Slime production was determined by using modified Christensen macrotube method and proteinase activity was measured by the method of Staib. Antifungal susceptibility was determined through the guidelines of National Committee for Laboratory Standards (NCCLS M27-A).

Caco-2 cell culture as a model for famotidine absorption.

The aim of the study was to determine penetration properties of Famotidine fro the formulations through colon adenocarcinoma (Caco)-2 cell monolayers and to compare in vitro with in vivo test results. It also aimed to determine the effect of particle size on the penetration properties of Famotidine when microsphere formulations were used. Famotidine was chosen as a model drug and Caco-2 cell culture model was used. Biodegradable Famotidine microspheres of poly(lactide-co-glycolide)(PLGA) polymer (50:50) were prepared by using multiple emulsion technique. Microspheres were coded according to their particle size and polymer[LHIV:60 microm Famotidine-PLGA(high viscosity), SHIV:6 microm Famotidine PLGA(high viscosity), LLIV:60 microm Famotidine-PLGA (low viscosity), SLIV:6 microm Famotidine-PLGA (low viscosity)]. Famotidine solution(5 mg/ml) and microsphere formulations were administered orally to mice and blood drug levels were determined and compared with the Caco-2 cell experiments. Permeability values of Famotidine through Caco-2 cells from various formulations were determined (log k(solution) = 7,274 +/- 0,010,log kSHIV = -3,884 +/- 0,033,log kLHIV = -2,300 +/- 0,009,log kSLIV = -4,076 +/- 0,208,log kLLIV = 3,525 +/- 0,045). Our results showed that H2 receptor antagonists alter the barrier properties of the Caco-2 cell monolayer by causing an increment in the tightness of the tight junctions. Therefore, amount of the H2 receptor antagonist-like drug at the site of action was found to be important as well as polymer type and particle size of microspheres for drug permeation. Permeation of the drug was lower when higher amounts of Famotidine were present at the diffusion site. A controlled release dosage form of H2 receptor antagonist-like drugs may be beneficial for long-term treatments.

In vitro susceptibility of Candida species isolated from blood culture to some antifungal agents.

Fungal infections are among the major causes of morbidity in cancer patients. In order to optimize the treatment of such patients, it is critical to determine the type of fungus causing infection as well as its susceptibility to antifungals. This study was undertaken to the study resistance of Candida spp. isolated from blood cultures of cancer patients to ketoconazole (KET), fluconazole (FLU), amphotericin B (AmpB), and flucytosine (FCU). A modified NCCLS M 27-A method was used to evaluate the activity of the species. Of the 56 Candida albicans isolates, 7 (12.5%) were resistant to FLU (MIC > or = 64 microg/ml), 6 (10.7%) were resistant to KET (MIC > or = 64 microg/ml) and 3 (5.3%) were resistant to FCU (MIC > or = 32 microg/ml). One (14.3%) of 7 C. parapsilosis isolates was resistant to FLU (MIC > or = 64 microg/ml). One (33.3%) of 3 C. tropicalis isolates was resistant to KET (MIC > or = 64 microg/ml). None of the C. guilliermondii or C. pelliculosa isolates was resistant to KET, FLU, AmpB, or FCU. Based on these results, AmpB is an effective antifungal agent that can be used against all Candida isolates.

The effect of various liposome formulations on insulin penetration across Caco-2 cell monolayer.

The aim of the study was to determine the penetration properties of various insulin containing liposome formulations through Caco-2 cell monolayer and to compare the in vitro test results with in vivo tests. The effect of sodium taurocholate as a penetration enhancer when it was added to the liposome formulation was also investigated. In vitro permeation experiments were performed in diffusion cells with the Caco-2 cell monolayer used as the membrane. Permeability values of various insulin containing liposome formulations through Caco-2 cells were determined (log k(insulin-solution) = -2.217 +/- 0.0723 cm.h(-1), log k(insulin-liposome) = -2.141 +/- 0.0625 cm.h(-1), log k(insulin-sodium tauroholate liposome)= -1.952 +/- 0.0623 cm.h(-1)). In vivo tests were performed in mice. Formulations were administered orally and blood glucose levels were determined and penetrations were compared with the Caco-2 cell experiment results. In conclusion, the permeability of insulin was increased across Caco-2 cell monolayer when the liposome sodium taurocholate (NaTC) formulation was used. The oral administration of insulin and NaTC incorporated liposomes significantly decreased blood glucose levels. Furthermore, it was shown that a high in vitro/in vivo correlation was observed using the Caco-2 cell monolayer model.

In vitro susceptibility of Candida species isolated from cancer patients to some antifungal agents.

This study was undertaken to study the resistance of Candida species isolated from oropharyngeal swabs of cancer patients to ketoconazole (KET), fluconazole (FLU), amphotericin B (AmpB), and flucytosine (FCU). The most common species identified was C. albicans, followed by C. tropicalis, C. glabrata, C. famata, C. krusei, C. kefyr, and C. gulliermondii. The minimum inhibitory concentration (MIC) of the antifungal agents was evaluated by RPMI 1640 medium with microdilution method. There were no C. albicans strains resistant to KET, FLU and AmpB. All Candida isolates were found highly susceptible to AmpB (MIC AmpB < 1 microg/ml), followed by KET (MIC KET < or =8 microg/ml), FLU (MIC FLU < or =8 microg/ml) and FCU (MIC FCU < or =4 microg/ml). The main conclusion of this study is that prophylactic therapy planned according to typing and antifungal susceptibility will contribute to the prevention of invasive fungal infections in immunosuppressied oncology patients.