Biofilm formation in Malassezia pachydermatis strains isolated from dogs decreases susceptibility to ketoconazole and itraconazole

Malassezia pachydermatis is a commonly isolated yeast in veterinary dermatology that can produce biofilms in vitro and in vivo, lowering its susceptibility to antimicrobial drugs. The aim of this study was to determine and compare the in vitro susceptibility of planktonic cells and biofilms of M. pachydermatis isolates to ketoconazole and itraconazole. The presence of biofilm formation was confirmed by crystal violet staining and absorbance measurement at 595 nm wavelength, and by a scanning electron microscopy method. Cell viability was determined by the Celltiter 96 Aqueous One solution assay containing a water-soluble tetrazolium compound (MTS) with absorbance measurement at 490 nm. Planktonic cell minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) of ketoconazole and itraconazole were very low: MIC90 and MFC90 were 0.032 and 0.125 μg/ml for ketoconazole, while 0.063 and 0.25 μg/ml for itraconazole, respectively. Also, the half maximal effective concentrations (EC50) of itraconazole were higher for planktonic cells and biofilms compared to ketoconazole. The EC50 values of ketoconazole were 18–169 times higher and those of itraconazole 13–124 times higher for biofilms than for planktonic cells. Biofilm EC50 levels exceeded MICs 103–2060 times for ketoconazole and 84–1400 times for itraconazole. No significant difference was found between these values of the two substances. In conclusion, biofilms of all examined M. pachydermatis strains were much less susceptible to ketoconazole and itraconazole than their planktonic forms

Effectiveness of antipseudomonal antibiotics and mechanisms of multidrug resistance in Pseudomonas aeruginosa

Pseudomonas aeruginosa is a leading human pathogen that causes serious infections at various tissues and organs leading to life threatening health problems and possible deadly outcomes. Resistance patterns vary widely whether it is from hospitals or community acquired infections. Reporting resistance profiles to a certain antibiotics provide valuable information in a given setting, but may be extrapolated outside the sampling location. In the present study, P. aeruginosa isolates were screened to determine their susceptibilities against antipseudomonal antimicrobial agents and possible existing mechanisms of resistance were determined. Eighty-six isolates of P. aeruginosa were recovered. Isolates representing different resistance profiles were screened for the existence of three different resistance mechanisms including drug inactivation due to metallo-?-lactamases, drug impermeability by outer membrane proteins and drug efflux. All tested isolates showed uniform susceptibility (100%, n = 86/86) to piperacillin, meropenem, amikacin, and polymyxin B. A single isolate was found to be imipenem resistant (99%, n = 85/86). The possible mechanisms of resistance of P. aeruginosa to imipenem involve active drug efflux pumps, outer membrane impermeability as well as drug inactivating enzymes. These findings demonstrate the fundamental importance of the in vitro susceptibility testing of antibiotics prior to antipseudomonal therapy and highlight the need for a continuous antimicrobial resistance surveillance programs to monitor the changing resistance patterns so that clinicians and health care officials are updated as to the most effective therapeutic agents to combat the serious outcomes of P. aeruginosa infections.Scopu

Effectiveness of antipseudomonal antibiotics and mechanisms of multidrug resistance in Pseudomonas aeruginosa

Pseudomonas aeruginosa is a leading human pathogen that causes serious infections at various tissues and organs leading to life threatening health problems and possible deadly outcomes. Resistance patterns vary widely whether it is from hospitals or community acquired infections. Reporting resistance profiles to a certain antibiotics provide valuable information in a given setting, but may be extrapolated outside the sampling location. In the present study, P. aeruginosa isolates were screened to determine their susceptibilities against antipseudomonal antimicrobial agents and possible existing mechanisms of resistance were determined. Eighty-six isolates of P. aeruginosa were recovered. Isolates representing different resistance profiles were screened for the existence of three different resistance mechanisms including drug inactivation due to metallo-?-lactamases, drug impermeability by outer membrane proteins and drug efflux. All tested isolates showed uniform susceptibility (100%, n = 86/86) to piperacillin, meropenem, amikacin, and polymyxin B. A single isolate was found to be imipenem resistant (99%, n = 85/86). The possible mechanisms of resistance of P. aeruginosa to imipenem involve active drug efflux pumps, outer membrane impermeability as well as drug inactivating enzymes. These findings demonstrate the fundamental importance of the in vitro susceptibility testing of antibiotics prior to antipseudomonal therapy and highlight the need for a continuous antimicrobial resistance surveillance programs to monitor the changing resistance patterns so that clinicians and health care officials are updated as to the most effective therapeutic agents to combat the serious outcomes of P. aeruginosa infections.Scopu

Preparation of Veterinary Premix with Dual Active Ingredients in Granular Form

The aim of the study was to investigate the preparation of granular veterinary premix containing two different antibiotics by fluid bed granulation process. The particle size and density of the active ingredients were investigated for the proper selection of the filler material. The used antibiotics were tylosin tartarate and colistin sulfate, while isomalt sugar alcohol and cellulose materials were selected as filler and binder, respectively. The colistin sulfate was fed together with the binder solution because of its low density, fine particle size and relatively low (1.2%) concentration in the product. The type and concentration of the binder in its solution, the feeding rate and the total amount of added binder solution were optimized for obtaining dust free granules with desirable abrasion resistance and good flowability. The active ingredient content for both antibiotics was preserved even at the elevated temperature applied during the fluid granulation process

Két antibiotikumot tartalmazó gyógypremix granulált formátumának előállítása = Preparation of Medicated Feed Premix with Two Active Ingredients in Granular Form

The aim was to produce dust free granulated premix containing two antibiotics. Trierra A.U.V. veterinary premix was used as reference with 15 % of oxytetracycline and 7.5 % of bacitracin zinc (feed grade) content. Besides the elimination of fine particle content the preservation of the active ingredients content, the bioequivalence to the reference product and the stability during storage were the prescribed requirements during the development of a new formulation. Granulation was carried out in a laboratory size fluid granulator. The product active ingredient content was adjusted 15 w/w% for oxytetracycline dihydrate and 0.75 m/m% bacitracin zinc (pharma grade). The demonstrated GTRI1- 6 granules were prepared on wheat starch and isomalt matrix materials. For binder hydroxypropyl methylcellulose was used. The wettability of the binder was aided by isomalt, and for bacitracin zinc Tween 80 was used for the same propose during the binder solution preparation. The produced granules fine particle size fraction (<100 μm) were between 0.0 and 0.8 m/m%. The active ingredient content was preserved during the formulation, i. e. the decrease comparing to expected content was not exceed 5 %. The bioequivalence test showed similar dissolution profile for both antibiotics to Trierra A.U.V in case of granules were produced on isomalt carrier, that is GTRI2, 3 and 5. During six-month storage all the three granules showed eligible stability, i. e. the sixth moth highest value of active ingredient content decrease was 1.66 % for oxytetracycline and 4.9 % for bacitracin zinc

Impaired Immunosuppressive Effect of Bronchoalveolar Mesenchymal Stem Cells in Hypersensitivity Pneumonitis: preliminary findings

K

Gentamicin sulphate permeation through porcine intestinal epithelial cell monolayer

Gentamicin is an aminoglycoside antibiotic widely used in combination with dimethyl sulphoxide (DMSO) in topical drug formulations. It is not known, however, whether DMSO can enhance the permeation of gentamicin through biological membranes, leading to oto- and nephrotoxic side effects. A simple and reliable high-performance liquid chromatographic (HPLC) method was applied for the quantitative determination of gentamicin collected from the apical and basolateral compartments of the porcine intestinal epithelial cell line IPEC-J2 cell monolayer using fluorometric derivatisation of the analyte with fluorenylmethyloxycarbonyl chloride (FMOC) prior to chromatographic run in the presence and absence of 1% DMSO. The lack of change in transepithelial electrical resistance (TER) demonstrated that gentamicin and 1% DMSO did not affect IPEC-J2 cell monolayer integrity via the disruption of cell membranes. Chromatographic data also ascertained that gentamicin penetration across the cell monolayer even in the presence of 1% DMSO was negligible at 6 h after the beginning of apical gentamicin administration. This study further indicates that the addition of this organic solvent does not increase the incidence of toxic effects related to gentamicin permeation