Yazar "Demirci, Mehmet" seçeneğine göre listele
Listeleniyor 1 - 6 / 6
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Efficacy of antimicrobial peptide LL-37 against biofilm forming Staphylococcus aureus strains obtained from chronic wound infections(Elsevier, 2022) Demirci, Mehmet; Yigin, Akin; Demir, CemilThe antimicrobial peptide LL-37 showed inhibitory effects against Staphylococcus aureus strains, which often responsible for wound infections. Understanding the molecular mechanisms of biofilm-containing wound infections is important. Thus, this study aimed to investigate both the antimicrobial and biofilm efficacy of LL-37 against biofilm-positive methicillin-susceptible S. aureus (MSSA) strains and biofilm-positive methicillin-resistant S. aureus (MRSA) strains obtained from chronic wound infections and its effect on different quorum sensing and virulence genes at suboptimal concentrations. Fifteen biofilm-forming MRSA and 15 biofilm-forming MSSA strains were included in this study. The minimum inhibitory concentration (MIC) values and biofilm formation were tested by microdilution methods. Real-time PCR was performed to determine gene expression levels. MIC values for LL-37 were 89.6 mg/L and 132.3 mg/L for MSSA and MRSA strains, respectively. No statistically significant difference was found between MRSA and MSSA strains in terms of the effect of LL-37 on biofilm formation. A statistically significant difference was found between MRSA and MSSA strains for atlA, RNAIII, and agrA gene expression levels following exposure to a suboptimal concentration of LL-37. Ultimately, the required LL-37 antimicrobial concentration was quite high; however, LL-37 antibiofilm concentration may be acceptable for use in humans against biofilm-forming MRSA and MSSA strains. This is the first study to investigate to effect of a suboptimal LL-37 concentration on gene expression levels of biofilm-forming MSSA and MRSA strains. LL-37 affected quorum sensing and biofilm producing mechanisms, even at suboptimal MIC concentrations.Öğe An Enzyme-Linked Immunosorbent Assay for Brucella Specific Antibody and Real-Time PCR for Detecting Brucella Spp. in Milk and Cheese in Sanliurfa, Turkey(UNIV AGRICULTURE, FAC VETERINARY SCIENCE, 2017) Altun, Serap Kilic; Yigin, Akin; Gurbilek, Sevil Erdenlig; Gurbuz, Semra; Demirci, Mehmet; Keskin, Oktay; Tel, Osman YasarThe objective of this study was to investigate the presence of anti-Brucella antibody and Brucella spp. DNA in cow, sheep and goat milk and in Urfa cheese collected from markets and bazaars in Sanliurfa, located in southeast of Turkey. A total of 258 samples consisting of 178 raw milk (48 cow milk, 65 sheep milk and 65 goat milk) samples and 80 Urfa cheese samples were investigated. Anti-Brucella antibody was detected by indirect ELISA (i-ELISA), and the presence of Brucella spp. DNA was screened by real time Polymerase Chain Reaction (RTPCR). 16.6% of the cow, 6.1% of the goat and 6.1% of the sheep milk and 16.25% of the cheese samples were found as positive for brucella antibodies by i-ELISA. The RT-PCR assay amplified Brucella DNA from 18.75, 7.6 and 6.1% cow, goat and sheep milk samples respectively. Brucella DNA was amplified from 22.5% cheese samples. The 11.2% and 13.9% of the samples were found as positive by i-ELISA and RT-PCR respectively. This study indicates that milk and milk products consumed in Sanliurfa poses a risk to public health in terms of brucellosis. The combining usage of both i-ELISA and RT-PCR methods could lead to more reliable results to detect anti-Brucella antibody and Brucella spp. DNA from milk and cheese samples. (C) 2016 PVJ. All rights reservedÖğe Giardia intestinalis Genotiplerinin, Real-Time PCR Yöntemi ile Dışkı Örneklerinden Belirlenmesi(Türk Mikrobiyoloji Cemiyeti Dergisi, 2018) Demirci, Mehmet; Yiğin, Akın; Demir, Cemil; Acel, Düriye PelinAmaç: Giardia intestinalis flagellalı, Giardiyaz’a neden olan bir protozoondur ve dünya çapında önemli bir sorundur. Moleküler yöntemlerle sekiz farklı genotipi saptanan G. intestinalis’de, A ve B genotipinin, insan ve memelilerde hastalıklarla ilişkili olduğu ve farklı genotiplerin, farklı klinik tablolar meydana getirebildiği bildirilmektedir. Biz de bu bilgiler ışığında, giardiyaz tanısı almış ve G. intestinalis pozitif saptanan dışkı örneklerinde bulunan G. intestinalis genotiplerinin dağılımını real-time PCR yöntemi ile belirlemeyi ve moleküler epidemiyolojik bir veri sunmayı amaçladık. Gereç ve Yöntem: Ocak 2016-Ocak 2018 tarihleri arasında, hem nativ hem de lugol ile mikroskobik olarak incelenen dışkı örnekleri içinde G. intestinalis kist ve/veya trofozoit’i pozitif bulunan 50 G. intestinalis pozitif hastanın dışkı numuneleri çalışmaya dâhil edildi. Dışkı örneklerinden DNA izolasyonu gerçekleştirildikten sonra genotip A ve genotip B için spesifik primerler kullanılarak real-time PCR ile analiz edildi. Bulgular: Çalışmamıza dâhil edilen 50 giardiyaz tanılı hastanın dışkı örneklerinde, 28’inde (%56) A genotipi saptanırken, 17’sinde (%34) B genotipi, 5’inde (%10) ise hem A, hem de B genotipi bulundu. Cinsiyete göre saptanan genotipler incelendiğinde, erkeklerde ve kadınlarda sırasıyla 25 (%50) ve 25 (%50) olarak bulundu. Sonuç: Sonuç olarak, çalışmamız ile ülkemizde giardiyaza neden olan ama ayrımı yalnızca moleküler yöntemlerle ortaya konabilen G. intestinalis genotipleri incelenerek, G. intestinalis’in A genotipinin, B genotipine oranla biraz daha fazla olduğu belirlendi. Ülkemizde G. intestinalis’in moleküler epidemiyolojisine yönelik veriler sınırlıdır. Bu çalışmanın buna katkı sağlayacağı düşüncesindeyiz.Öğe Presence of biofilm and adhesin genes in Staphylococcus aureus strains taken from chronic wound infections and their genotypic and phenotypic antimicrobial sensitivity patterns(2020) Demir, Cemil; Demirci, Mehmet; Yigin, Akin; Tokman, Hrisi Bahar; Cetik Yildiz, SongulThe purpose of this research was to examine biofilm (icaA, icaD and bap) and adhesin (clfA, fnbA, cna) genes, and also assess the genotypic and phenotypic antimicrobial resistance patterns of Staphylococcus aureus strains taken from wound specimens in Mardin, Turkey. A total of 220 wound specimens were investigated. The biofilm forming ability and resistance pattern for eleven antimicrobial agents were investigated by conventional and multiplex PCR methods. S. aureus were taken from 112 (50.9%) of 220 wound specimens. Moreover, biofilm production was found in 79 (70.5%) of the 112 S. aureus isolates. 97 (86.6%) strains of all isolates were positive for icaA and icaD, and 15 (13.4%) for bap. The adhesin genes, cna, fnbA and clfA were detected in 98 (87.5%), 87 (77.7%), and 75 (66.9%) strains, respectively. The numbers of MSSA and MRSA bearing antimicrobial resistance genes were 19 (16.96%) and 32 (28.57%) for blaZ, 9 (8.04%) and 17 (15.18%) for tetK, 6 (5.36%) and 14 (12.5%) for ermC, 2 (1.79%) and 7 (6.25%) for tetM, 0 (0%) and 5 (4.46%) for mecA, 2 (1.79%) and 4 (3.57%) for ermA, 1 (0.89%) and 2 (1.79%) for both tetK and tetM, respectively. Our findings indicate that multiplex PCR is a suitable way for identifying biofilm and adhesin producing S. aureus. Our data also provided a country-wide oversight of the S. aureus antimicrobial resistance gene profiles for the properly therapy of patients and to control the spreading of the resistance genes.Öğe Presence of Biofilm and Adhesin Genes in Staphylococcus aureus Strains Taken from Chronic Wound Infections and their Genotypic and Phenotypic Antimicrobial Sensitivity Patterns(Photodiagnosis and Photodynamic Therapy, 2020) Demir, Cemil; Demirci, Mehmet; Yigin, Akin; Bahar Tokman, Hrisi; Çetik Yıldız, SongulThe aim of this study was to investigate some biofilm (icaA, icaD and bap) and some adhesion (clfA, fnbA, cna) genes, and also evaluate the phenotypic and genotypic antimicrobial resistance patterns of Staphylococcus aureus strains isolated from wound samples in Mardin, Turkey. A total of 220 wound samples were studied. The biofilm forming ability and resistance pattern for eleven antimicrobial agents were investigated by conventional and multiplex PCR methods. S. aureus was isolated from 112 (50.9%) of 220 wound samples. Moreover, biofilm production was found in 79 (70.5%) of the 112 S. aureus isolates. 97 (86.6%) strains of all isolates were positive for icaA and icaD, and 15 (13.4%) for bap. The adhesin genes, cna, fnbA and clfA were detected in 98 (87.5%), 87 (77.7%), and 75 (66.9%) strains, respectively. The numbers of MSSA and MRSA carrying antimicrobial resistance genes were 19 (16.96%) and 32 (28.57%) for blaZ, 9 (8.04%) and 17 (15.18%) for tetK, 6 (5.36%) and 14 (12.5%) for ermC, 2 (1.79%) and 7 (6.25%) for tetM, 0 (0%) and 5 (4.46%) for mecA, 2 (1.79%) and 4 (3.57%) for ermA, 1 (0.89%) and 2 (1.79 %) for both tetK and tetM, respectively. Our findings indicate that multiplex PCR is a reliable method for identifying biofilm and adhesin producing S. aureus. Our data also provided a nationwide surveillance of the antimicrobial resistance gene profiles of S. aureus for the accurate treatment of patients and to control the dissemination of the resistance genes.Öğe Presence of Staphylococcus aureus, staphylococcal enterotoxins and antimicrobial resistance in traditionally produced raw milk cheeses(Journal of Food Safety and Food Quality-Archiv für lebensmittelhygiene, 2018-12) Gürbüz, Semra; Keskin, Oktay; Erdenliğ Gürbilek, Sevil; Tel, Osman Yaşar; Yiğin, Akın; Demirci, Mehmet; Demir, Cemir; Hassan, HalaThe objectives of this study was to investigate the presence of Staphylococcus aureus, distribution of classical staphylococcal enterotoxin (SE) SEA to SEE, relevant gene/s and antimicrobial resistance pattern of S. aureus isolated from traditionally produced raw milk cheeses. A total of 106 fresh white cheese samples were examined. The 25 (23.6 %) of 106 cheese samples were found to be contaminated with coagulase positive staphylococci (CPS). From 52 isolates identified as S. aureus, one or more SEs was detected in 38.4 % of the isolates by ELISA whereas one or more se genes were detected in 50 % of the isolates by RT PCR. SEE (75 %) and see gene (61.5 %) were detected most frequently, whereas SED and sed gene were not detected in any isolates. Overall, 63.5 % of isolates were resistant to antimicrobial agents with 59.6 %, 13.5 %, 5.8 %, 5.8 % and 3.8 % of the isolates were resistant to penicillin, erythromycin, tetracycline, cefoxitin and kanamycin, respectively. The results of this study have revealed that cheeses made from raw milk were highly contaminated with S. aureus, therefore, creates a risk for public health due to the presence of enterotoxins as well as resistant strains against antimicrobial agents.
