Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 49Citation - Scopus: 55Effects of Nisin and Lysozyme on Growth Inhibition and Biofilm Formation Capacity of Staphylococcus Aureus Strains Isolated From Raw Milk and Cheese Samples(International Association for Food Protection, 2012) Sudağıdan, Mert; Yemenicioğlu, AhmetEffects of nisin and lysozyme on growth inhibition and biofilm formation capacity of 25 Staphylococcus aureus strains isolated from raw milk (13 strains) and cheese (12 strains) were studied. Nisin was tested at concentrations between 0.5 and 25 μg/ ml; the growth of all strains was inhibited at 25 μg/ml, but the resistances of strains showed a great variation at lower nisin concentrations. In contrast, lysozyme tested at concentrations up to 5.0 mg/ml showed no inhibition on the growth of strains. Nisin used at the growth inhibitory concentration prevented the biofilm formation of strains, but strains continued biofilm formation at subinhibitory nisin concentrations. Lysozyme did not affect the biofilm formation of 19 of the strains, but it caused a considerable activation in the biofilm formation capacity of six strains. Twelve of the strains contained both biofilm-related protease genes (sspA, sspB, and aur) and active proteases; eight of these strains were nisin resistant. These results suggest a potential risk of S. aureus growth and biofilm formation when lysozyme is used in the biopreservation of dairy products. Nisin can be used to control growth and biofilm formation of foodborne S. aureus, unless resistance against this biopreservative develops. Copyright ©, International Association for Food Protection.Article Citation - WoS: 20Citation - Scopus: 20Screening Virulence Properties of Staphylococci Isolated From Meat and Meat Products(B W K Public Relations, 2009) Sudağıdan, Mert; Aydın, A.Virulence properties (biofilm formation, antibiotic susceptibility, production of extracellular enzymes and the presence of toxin genes) of staphylococci isolated from various meat and meat products were investigated. 22 Staphylococcus spp. (S. aureus n = 9, S. haemolytlcus n = 4, S. cohnii n = 3, S. saprophytics n = 3, S. hominis n = 1, S. simulans n = 1 and S. warneri n = 1) were isolated from 120 meat and meat product samples. 10 strains were biofilmformers. Although none of the strains was resistant to vancomycin, oxacillin, teicoplanin, ofloxacin and gentamicin, 8 strains were found to be resistant to penicillin and one strain was found to be resistant to erythromycin. In addition, all strains were negative for the mecA PCR. 8 strains showed lipolytic activity against Tween 80,10 strains against Tween 20, and 18 strains against tributyrin. Moreover, 9 strains showed proteolytic activity against casein, 11 strains against milk and 17 strains against skim milk containing media. Mostly S. aureus strains showed positive results for icaA-SA, nuc, geh, sspA, sspB, aur, serine protease gene, hla, hlb, set1, and etb. However, 7 of coagulase-negative staphylococci strains were found to carry see gene. As both prevalence and concentration of this bacterium were low, and no isolate contained all virulence factors, it is concluded that common hygiene and process control measures should be sufficient to control meatborne staphylococcal intoxication.Article Citation - WoS: 19Citation - Scopus: 19Biofilm Formation by Staphylococcus Epidermidis on Nitrogen Ion Implanted Cocrmo Alloy Material(John Wiley and Sons Inc., 2007) Öztürk, Orhan; Sudağıdan, Mert; Türkan, UğurStaphylococcus epidermidis is the primary cause of medical device-related infections due to its adhesion and biofilm forming abilities on biomaterial surfaces. For this reason development of new materials and surfaces to prevent bacterial adhesion is inevitable. In this study, the adhesion of biofilm forming S. epidermidis strain YT-169a on nitrogen (N) ion implanted as well as on as-polished CoCrMo alloy materials were investigated. A medical grade CoCrMo alloy was ion implanted with 60 keV N ions to a high dose of 1.9 × 10 18 ions/cm2 at substrate temperatures of 200 and 400°C. The near-surface implanted layer crystal structures, implanted layer thicknesses, and roughnesses were characterized by XRD, SEM and AFM. The number of adherent bacteria on the surfaces of N implanted specimens was found to be 191 × 106 CFU/cm2 for the 200°C and 70 × 106 CFU/cm2 for the 400°C specimens compared to the as-polished specimen (3 × 106 CFU/cm2). The adhesion test results showed that S. epidermidis strain YT-169a adhere much more efficiently to the N implanted surfaces than to the as-polished CoCrMo alloy surface. This was attributed mainly to the rougher surfaces associated with the N implanted specimens in comparison with the relatively smooth surface of the as-polished specimen.