1. Microbial colonization of irradiated pathogenic yeast to catheter surfaces: Relationship between adherence, cell surface hydrophobicity, biofilm formation and antifungal susceptibility. A scanning electron microscope analysis
- Author
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Farrag Ha, Mohamed El-Sayed Zg, A-Karam El-Din A, Abdel-Latifissa S, and Kamal Mm
- Subjects
Nystatin ,Antifungal Agents ,Cryptococcus ,Urinary Catheters ,Rhodotorula ,Saccharomyces ,Microbiology ,Minimum inhibitory concentration ,Drug Resistance, Fungal ,Yeasts ,Cell Adhesion ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Virulence ,Radiological and Ultrasound Technology ,biology ,Cell Membrane ,Biofilm ,Prototheca ,biology.organism_classification ,Yeast ,Urinary Bladder Neoplasms ,Gamma Rays ,Biofilms ,Catheter-Related Infections ,Microscopy, Electron, Scanning ,Hydrophobic and Hydrophilic Interactions ,medicine.drug - Abstract
Technological advances such as long-term indwelling catheters have created milieu in which infections are a major complication. Thus it is essential to be able to recognize, diagnose, and treat infections occurring in immunocompromised patients.Adherence assay and quantitation of biofilms was performed by a spectrophotometric method, hydrophobicity was evaluated by adhesion to p-xylene. The minimum inhibitory concentration (MIC) of Nystatin was carried out by a well dilution method.Out of 100 bladder cancer patients, 23 pathogenic yeast isolates were identified. The samples were taken from urinary catheters and urine collected from their attached drainage bags. Pathogenic yeast identified were species of Candida, Cryptococcus, Saccharomyces, Blastoschizomyces, Trichosporn, Hansenula, Prototheca and Rhodotorula. With the exception of Rhodotorula minuta, the yeast were sensitive to the antimycotic agent (Nystatin) used before and after in vitro gamma irradiation at 24.41 Gy as measured by a disc diffusion method. All tested yeast strains were slime producers and showed positive adherence reactions. There were considerable differences in adherence measurements after irradiation. An increase in adherence measurement values (using a spectrophotometric method) after irradiation were detected in four strains whereas eight other strains showed a reduction in their adherence reaction. The cell surface hydrophobicity (CSH) was evaluated by adhesion to p-xylene. Candida tropicalis showed a hydrophobic reaction with an increase in the cell surface hydrophobicity after irradiation. Scanning electron microscopy of irradiated C. tropicalis showed marked abnormalities in cell shape and size with significant reduction in adherence ability at the MIC level of Nystatin (4 μg/ml).More basic research at the level of pathogenesis and catheter substance is needed to design novel strategies to prevent fungal adherence and to inhibit biofilm formation.
- Published
- 2015
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