Browsing by Author "Hortac Istar, Elvan"

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    Biofilm Formation Research of Coagulase-Negative Staphylococci Isolates' Isolated from Blood and Hand Culture at Nanofilm Covered Micro Plaques by Plasma Polymerization Technique: An Experimental Model
    (2017) Hortac Istar, Elvan; Gocmen, Julide Sedef; Cokeliler, Dilek; Mutlu, Mehmet; Kaleli Can, Gizem; Alparaslan, Sezin; Cetin, Ceren; Kartal, Naz; Ozcelik, Ugur Can; Aycan, Cagri; 0000-0002-4335-6897; 0000-0001-6423-7523; AAP-6138-2021
    Introduction: Coagulase-negative staphylococci (CNS) can protect themselves from the effects of antibiotics by producing biofilms through breeding on biomaterials, medical equipment and devices. It is possible to influence biofilm formation with the aid of various surface modifications. In our study, plasma polymerization method, which is a surface modification technique, was used. The plasma polymerization technique is an environmentally-friendly technique that allows you to modify the nanometer level only at the surface without affecting the stack using the fourth state of the material. The possibility to generate surfaces with different properties (hydrophilic, hydrophobic, biocompatible etc.) by the help of various monomers and gases has made this technique more popular. In this study, the effect of the microplate surfaces modified by three different monomers on the biofilm formation of CNS was investigated. Materials and Methods: A total of 60 isolated CNS isolates from blood and hand cultures were included into the study. As control strains, Staphylococcus epidermidis ATCC 35984, known to be biofilm positive, and S. epidermidis ATCC 12228 which do not form biofilm, were used. Slime formation was determined by the quantitative plaque assay method described by Christensen. In microplates, which were plain or modified by three different monomers, the biofilm formation behavior of all strains was investigated simultaneously and comparatively. Results: There was no difference in biofilm positivity between strains isolated from hand and blood. A total of 71.6% biofilm formation was observed on microplates, which were not coated with plasma technique, and on plasma-modified microplated surfaces, 80% (monomer: 3- mercaptopropionic acid), 65% (monomer: 2-hydroxyethyl methacylate) and 31.6% (monomer: ethylene glycol dimethacylate) biofilm formation was observed, respectively. It was found that ethylene glycol dimethacrylate in three monomers significantly inhibited biofilm formation when compared to other monomers. Conclusion: In recent years CNS, especially S. epidermidis has become the most frequently isolated bacteria in catheter infections and responsible for the 28% of nosocomial bacteremia. The widespread use of prosthetic and permanent devices has been shown as a reason for the increase in the frequency of this effect. In 90% of patients with S. epidermidis bacteremia, there is an intravascular catheter history. Biofilm is an extracellular structure containing water, proteins and carbohydrates and is responsible for the unwanted adhesion of microorganisms to host cells and artificial surfaces. The biofilm mechanism can be altered by the interaction between the material surface and the bacterial surface. In our study, in-vitro results were obtained showing the potential to reduce the risk of biofilm-associated infection by microorganism biofilm formation on modified surfaces with appropriate monomer selection.
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    Determination of Biofilm Formation Properties of Methicillin Sensitive and Resistant Staphylococcus aureus Isolates by Conventional and Molecular Methods
    (2020) Hortac Istar, Elvan; Aliskan, Hikmet Eda; Basustaoglu, Ahmet; 0000-0002-2571-0637; 0000-0001-9060-3195; 32723278; AAI-8926-2021; AAE-2282-2021
    Biofilm-related infections are considered as among the foremost causes of treatment failure nowadays. One of the most common causes of biofilm-related infections is Staphylococcus aureus. It becomes extremely difficult to determine the appropriate treatment protocol while biofilm-related infections are coexisting with bacterial methicillin resistance. The aim of this study was to observe the potential of biofilm formation of methicillin-sensitive and -resistant S.aureus strains isolated from different clinical specimens and to determine reliable and effective methods for biofilm detection. A total of 200 S.aureus strains (100 methicillin-resistant and 100 methicillin-susceptible) isolated from 107 wound, 93 blood and catheter specimens, which were accepted as causative agents, included in the study. In order to determine the methicillin sensitivity, oxacillin minimal inhibitory concentration value obtained by an automated system and cefoxitin disc diffusion method were evaluated together. Biofilm formation was investigated by modified Christensen (MC), MTT, BioTimer and Congo Red Agar (CRA) methods, and the presence of ica operon responsible for biofilm formation was also observed by polymerase chain reaction. It has been shown that methicillin-resistant isolates produce biofilms in a shorter time and higher rate, and their biofilm structure is denser than methicillin-sensitive isolates in all MC, MTT and BioTimer methods. There was no difference between blood and wound isolates in biofilm formation. The most sensitive and specific conventional methods were MTT and BioTimer methods respectively. There was no significant difference between the isolates containing a gene region of icaADBC operon and the biofilm forming isolates according to MC, MTT, BioTimer and CCA methods. There was a high correlation between the presence of biofilm and ica positivity, and the tendency to form biofilm augmented as the number of ica genes increased. It has been emphasized that more virulent strains such as methicillin-resistant S.aureus have a higher tendency to form biofilm, and these two resistance mechanisms have been shown to support each other as cascade. ica detection may be an important reagent in itself for the detection of virulent strains, thus detection of the ica presence may be an early marker of treatment decisions, determination of protection strategies, and struggle with biofilm-related infections. In cases where molecular methods are not available, the existence of quick, easy-to-apply and reliable conventional methods to detect biofilm formation is extremely important. All conventional methods used in this study seem to be sufficient in this respect. MC and MTT methods stand out in terms of biofilm quantitation. BioTimer method is a very new and remarkable test used to detect biofilm formation. In conclusion, determining the potential of biofilm formation of colonizing or causative agents and taking essential precautions before interventional procedures will decrease biofilm related infections and related morbidity and mortality.