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    Antimicrobial Resistance and Virulence Genes of Enterococci Isolated from Water Buffalo's Subclinical Mastitis
    (2022) Ürer, Ece Koldaş; Tek, Erhan; Aslantaş, Özkan; Yılmaz, Mehmet Ali; Ergün, Yaşar
    This study aimed to investigate the antimicrobial resistance and virulence genes of enterococci isolated from water buffalo’s subclinical mastitis cases. The antimicrobial susceptibilities of the isolates were determined by the disc diffusion method. Identification at the species level of enterococci, virulence [aggregation substance (asa1), gelatinase (gelE), cytolysin (cylA), enterococcal surface protein (esp), and hyaluronidase (hyl)] and resistance genes [macrolide (ermA, ermB, mefA/E) and tetracycline (tetK, tetL, tetM, tetO, and tetS)] were investigated by polymerase chain reaction (PCR). Overall, Enterococcus spp. was recovered from 65 of 200 (32.5%) mastitic milk samples, comprising E. faecium (n=26), E. durans (n=22), E. faecalis (n=12), and E. hirae (n=5). Most isolates (56.9%) were susceptible to all tested antibiotics. The rest of the isolates showed various rate of resistance against rifampicin (23.1%), tetracycline (21.5%), quinupristin-dalfopristin (10.8%), ciprofloxacin (7.7%), erythromycin (6.2%), and chloramphenicol (3.1%). Out of 65 enterococci, only 16 (24.6%) were detected to have virulence genes, of which 12 were positive for gelE, seven were positive for esp, two were positive for asa1, and one was positive for hlyA. The gene cylA was not detected in any isolate tested. Resistance to tetracycline was mainly associated with tetM. Two erythromycin-resistant isolates were positive for ermB, and one was positive for mefA/E. This study was the first to report species distribution, antimicrobial susceptibility, and virulence traits of enterococci isolated from subclinical mastitis of water buffaloes in Çorum Province, Türkiye.
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    Antimicrobial susceptibility and biofilm forming ability of staphylococci from subclinical buffalo mastitis
    (Cambridge Univ Press, 2023) Urer, Ece Koldas; Aslantas, Ozkan; Tek, Erhan; Yilmaz, Mehmet Ali; Ergun, Yasar
    The starting objective of this research communication was to determine the prevalence of subclinical mastitis in buffalo in Turkey. We also seeked to isolate and identify staphylococci, determine their antimicrobial susceptibilities and biofilm-forming abilities as well as investigating the presence of biofilm-related genes and microbial surface components recognizing adhesive matrix molecules. A total of 107 (66.9%) staphylococci (28 S. aureus and 79 coagulase-negative staphylococci, CoNS) were isolated from 160 mastitic milk samples collected from 200 lactating water buffalos. The staphylococci were especially resistant to beta-lactams except for cefoxitin but were less resistant to the other antimicrobials that were tested. Based on the Congo red agar method, 92.9% of the S. aureus and 70.9% of the CoNS isolates were positive for biofilm-forming ability, while all S. aureus and 97.5% of CoNS isolates were positive by a microtiter plate analysis. The presence of icaA and icaD genes was not always correlated with biofilm synthesis, and even in the absence of these genes, the isolates were able to synthesize biofilm.
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    Considering potential roles of selected MicroRNAs in evaluating subclinical mastitis and Milk quality in California mastitis test (+) and infected bovine milk
    (Wiley, 2024) Ozkan, Huseyin; Keceli, Hasan Huseyin; Kaya, Ufuk; Dalkiran, Sevda; Yuksel, Murat; Tek, Erhan; Yakan, Akin
    This study investigates the relationships between subclinical mastitis and milk quality with selected microRNAs in cow milk. California Mastitis Test (CMT)-positive (n = 20) and negative (n = 20) samples were compared (Experiment I). Additionally, samples with CMT-positive but microbiological-negative, as well as positive for only Staphylococcus subspecies (Staph spp.) and only Streptococcus subspecies (Strep spp.) were examined (Experiment II). Four groups were formed in Experiment II: Group I (CMT and microbiological-negative) (n = 20), Group II (CMT-positive but microbiological-negative) (n = 10), Group III (Staph spp.) (n = 5), Group IV (Strep spp.) (n = 5). While electrical conductivity, somatic cell count (SCC), malondialdehyde (MDA) increased, miR-27a-3p and miR-223 upregulated and miR-125b downregulated in the CMT-positive group in Experiment I. SCC and MDA were higher in CMT-positive groups. miR-27a-3p and miR-223 upregulated in Groups III and IV. While miR-155 is upregulated, miR-125b downregulated in Group IV. Milk fat is positively correlated with miR-148a and miR-223. As miR-27a-3p positively correlated with SCC and MDA, miR-125b negatively correlated with electrical conductivity and SCC. miR-148a and MDA were positively correlated. miR-155 was correlated with fat-free dry matter, protein, lactose, and freezing point. miR-223 was positively correlated with SCC and miR-148a. Results particularly highlight miR-27a-3p and miR-223 as potential biomarkers in subclinical mastitis, especially those caused by Staph spp. and Strep spp., while miR-148a, miR-155, and miR-223 stand out in determining milk quality.
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    EFFICACY OF CAPSAICIN ON CELL ADHESION AND INVASION OF ORAL PATHOGENS
    (Inst. Nat. Cercetare-Dezvoltare Text. Pielarie, 2022) Tek, Erhan; Duran, Nizami
    Streptococcus pyogenes, Streptococcus mutans, and Candida albicans are important human pathogens and their infections in the mouth, mouth, and throat are important. Prophylaxis against oral and respiratory tract infections is of great importance in terms of both reducing the use of antibiotics and lowering the infection frequency. This study investigated the antimicrobial activity of Capsaicin against S. mutans, C. albicans, and S. pyogenes. Non-cytotoxic concentration of Capsaicin was determined in the Vero cell line by the MTT method. Efficacy studies were performed within these determined non-cytotoxic concentrations. The efficacy of single and different combinations of these three biological components on cell adhesion and invasion. The non-toxic concentration of capsaicin on Vero cells was <1.35 ?g/ml. Capsaicin exhibited significant antimicrobial activity against S. pyogenes, S. mutans, and C. albicans. Moreover, capsaicin was statistically significantly effective against host cell adhesion and invasion against S. mutans, S. pyogenes and C. albicans compared to the control group. The results showed that capsaicin is a highly potent antibacterial agent against S. pyogenes, and S. mutans, as well as an important prophylactic agent for fungal infections. As a result, we think that capsaicin is a useful molecule for the provision and maintenance of both respiratory diseases and oral health. © 2022 Toate drepturile asupra acestei edi?ii sunt rezervate editorilor.
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    Genotyping, drug resistance and virulence factors of Candida species isolated from patients using long-term inhaled steroids
    (Wiley, 2021) Dikmen, Nursel; Duran, Nizami; Ay, Emrah; Cimen, Funda; Tek, Erhan
    Aims In this study, it was aimed to determine the isolation frequency and species distribution of Candida species isolated from asthmatic patients using long-term inhaled steroids. It was also aimed to determine the drug resistance patterns and the frequency of erg11, HWP1, ALS1, INT1, SAP1 PLB1 genes in isolates. Methods Genotyping of Candida strains isolated from patients and healthy control group was performed by PCR-RFLP method. Drug resistance was investigated phenotypically, and the presence of erg11 resistance genes and HWP1, ALS1, INT1, SAP1 PLB1 virulence genes were investigated by PCR method. Results C albicans was the most isolated species in steroid-using patients and healthy control groups (patients: 44.2%; control group: 30.8%). C tropicalis and C glabrata were found to have the highest rates of non-albicans Candida in patients with 17.4% and 13.77%, respectively. Azole resistance was found to be significantly higher in isolates isolated from patients compared to the control group. Similarly, the presence of erg11 resistance gene was highest in C albicans (17.65%), C glabrata (12.5%) and C tropicalis (8.3%) strains in the control group, while C parapsilosis was highest in patients. (57.1%) and C glabrata (54.2%) strains. Compared to the control group, the virulence of Candida strains isolated from the patients was found to be higher. Presence of HWP1, ALS1, INT1, SAP1 and PLB1 genes in patients were determined as 72.1%, 63.9%, 68.9%, 57.38% and 54.5%, respectively. These rates were 29.4%, 35.3%, 25.5%, 17.7% and 23.5% in the healthy control group, respectively. Conclusions In asthma patients using long-term inhaled steroids, both Isolation rates of Candida species, drug resistance rates, presence of virulence genes were found to be significantly higher in patients than in the control group. We think that this may be due to the suppression of cellular immunity by long-term steroid use.
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    Glycyrrhetinic asit, streptococcus thermophilus ve lactobacillus casei'nin helicobacter pylori'ye karşı in-vitro, in-vivo etkinliği ve moleküler mekanizmaları
    (Hatay Mustafa Kemal Üniversitesi, 2022) Tek, Erhan; Duran, Ni̇zami̇
    Giriş & Amaç: H. pylori insanlarda gastrit, doudenal ülser ve gastrik kanserle ilişkilendirilen dünya nüfusunun yaklaşık yarısından fazlasında bulunan bir patojendir. Biz bu çalışmada H. pylori'ye karşı G. asit, S. thermophilus ve L. casei'nin biyokomponentlerinin AGS hücre hattında ve deneysel olarak oluşturulmuş sıçan gastrit modelinde etkinliklerinin araştırılmasını amaçladık. Yöntem: Bileşiklerin anti-H. pylori etkinliği, hastalığın progresyonunda önemli etkinlikleri olduğu bilinen NF-κB, IL-1B, IL-6, IL-8, IL-10, TNF-α, COX-2, FOX-M1 ve IL-33 genlerinin ekspresyonları seviyeleri RT-PCR yöntemiyle belirlenerek araştırıldı. Ayrıca H. pylori ile deneysel olarak oluşturulmuş sıçan gastrit modelinde bileşiklerin ve farklı kombinasyonlarının etkinliği standart tedavi grubuyla kıyaslı olarak mikrobiyolojik ve histopatolojik olarak da değerlendirildi. Bulgular: Deneylerde S. thermophilus tedavi grubunda NF-kB, TNF-α, COX-2 ve IL-1B, IL-6, IL-33, FOX-M1 ve IL-8 gen ekspresyonları anlamlı derecede azaldığı, IL-10 ekspresyonunun ise anlamlı düzeyde arttığı tespit edilmiştir. Gen ekspresyonları üzerindeki bu etkinliklerin S. thermophilus artı L. casei artı antibiyotik ve S.thermophilus artı G.asit artı antibiyotik tedavi grupları ile S. thermophilus artı L. casei artı G. asit artı antibiyotik dörtlü kombine tedavi gruplarında güçlü sinerjistik etkilerle ortaya çıktığı saptanmıştır. S. thermophilus tedavi grubunda hayvanlarda H. pylori eradikasyonu S. thermophilus tedavi grubunda tam olarak sağlanırken, G. asit grubunda eradikasyon oranı %60, ve L. casei ve antibiyotik tedavi grubunda ise %80 idi. S. thermophilus tedavi grubunda ödem ve lökosit infiltrasyonu görülmezken, diğer gruplarda lenfosit ve lökosit infiltrasyonu ile hafif ödem varlığı da tespit edildi. Üçlü kombine tedavi gruplarında anti-H. pylori etkinliği ikili kombine tedavi gruplarında bakteri eradikasyonu açısından daha etkili idi. Üçlü kombine tedavi uygulanan iki grupta da (S. thermophilus artı L. casei artı antbiyotik ve S. thermophilus artı G. asit artı antibiyotik tedavi grupları) hayvanların mide dokularında H. pylori'ye rastlanmazken, her ki grupta da orta düzeyde lenfosit infiltrasyonu ile hafif ödem ve düşük lökosit infiltrasyonu tespit edildi. S. thermophilus artı L. casei artı G. asit artı antibiyotik kombinasyonundan oluşan dörtlü tedavi grubunda ise H. pylori eradikasyonunun tam olduğu, mide dokusunda lökosit infiltrasyonuna ve ödeme rastlanmadığı, sadece hafif lenfosit infiltrasyonun olduğu tespit edildi. XIV Sonuç: S.thermophilus tedavi grubunda birçok yangısal sitokinin gen ekspresyon düzeylerinde azalma tespit edilirken dörtlü kombinasyon grubunda önemli sinerjistik etkiler belirlenmiştir. Ayrıca S.thermophilus tedavi grubu ile dörtlü tedavi grubunda gerek H.pylori eradikasyonunun ve gerekse de histolojik açıdan doku iyileşmesinin tam olması sebebiyle hem yeni tedavi yaklaşımlarının oluşturulmasında hem de mevcut terapötik yöntemlerin iyileştirilmesi açısından oldukça önemli olabileceğini düşünmekteyiz.
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    Isolation of ampicillin and vancomycin resistant Enterococcus faecium from dogs and cats
    (Kafkas Üniversitesi, 2019) Aslantaş, Özkan; Tek, Erhan
    In this study, it was aimed to determine the occurence of ampicillin and vancomycin resistant enterococci (ARE and VRE) species in dogs and cats, antimicrobial susceptibility and virulence genes (asa1, esp, gelE, hyl, cylA) of the isolates. Minimal inhibitor concentration (MIC) values of ampicillin and vancomycin were determined by macro dilution method and E-test, respectively. For this purpose, 531 rectal swabs collected from dogs (n=276) and cats (n=255) from three different cities (İstanbul, Ankara and Mersin) were examined. ARE was detected in 60 (21.7%) of dogs and in 47 (18.4%) of cats. VRE was detected in one dog and two cats. All ARE and VRE isolates were identified as Enterococcus faecium by polymerase chain reaction (PCR), and showed multi-drug resistance (MDR) phenotype. A small number of AREfm isolates (4.7%) carried virulence gene. To the authors’ knowledge, the study is first reporting vanA gene harboring VREfm in dogs in Turkey. The results indicated that both dogs and cats were frequent carriers of AREfm. Due to close contact with humans, dogs and cats may play an important role in the spread of these nosocomial pathogens in the community. Therefore, further molecular studies are needed to elucidate the possible role of animal originated AREfm and VREfm strains in human nosocomial infections.
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    New chalcone derivatives as effective against SARS-CoV-2 agent
    (Wiley-Hindawi, 2021) Duran, Nizami; Polat, M. Fatih; Aktas, Derya Anil; Alagoz, M. Abdullah; Ay, Emrah; Cimen, Funda; Tek, Erhan
    Aims Flavonoids and related compounds, such as quercetin-based antiviral drug Gene-Eden-VIR/Novirin, inhibit the protease of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The alkylated chalcones isolated from Angelica keiskei inhibit SARS-CoV proteases. In this study, we aimed to compare the anti-SARS CoV-2 activities of both newly synthesized chalcone derivatives and these two drugs. Methods Determination of the potent antiviral activity of newly synthesized chalcone derivatives against SARS-CoV-2 by calculating the RT-PCR cycling threshold (C-t) values. Results Antiviral activities of the compounds varied because of being dose dependent. Compound 6, 7, 9, and 16 were highly effective against SARS-CoV-2 at the concentration of 1.60 mu g/mL. Structure-based virtual screening was carried out against the most important druggable SARS-CoV-2 targets, viral RNA-dependent RNA polymerase, to identify putative inhibitors that could facilitate the development of potential anti-coronavirus disease-2019 drug candidates. Conclusions Computational analyses identified eight compounds inhibiting each target, with binding affinity scores ranging from -4.370 to -2.748 kcal/mol along with their toxicological, ADME, and drug-like properties.
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    Sütçü İneklerde Subklinik Mastitislerde Meme İçi Ozon Tedavisinin İyileştirici Etkisi
    (2020) Dolğun, İbrahim; Sarıbay, Mustafa Kemal; Tek, Erhan
    Çalışmada subklinik mastitis teşhisi konulan ineklerde ozon gazı tedavisinin iyileştirici etkisinin belirlenmesi amaçlandı.Çalışmanın materyalini laktasyondaki 20 baş ineğe ait 24 adet subklinik mastitisli meme lobu oluşturdu. Subklinik mastitislihayvanların tespiti amacıyla, her ineğin dört meme lobundan ayrı ayrı alınan süt örneklerine CMT uygulandı ve CMT pozitifreaksiyon veren ineklerden bakteriyolojik muayene amacıyla numune alındı. İnekler iki gruba ayrıldı, ilk gruba (Grup I, n=10)3 gün süresince ve 24 saat ara ile antimastit preparatı (Tetra delta LC®, Pfizer) meme içi yolla uygulandı. İkinci gruba (Grup II,n=10) ozon jenaratöründen (Genozon®) 6 mg/lt ozon hesabıyla, 1-5 lt arası ozon/oksijen gazı, 1 lt/dk hesabıyla 3 günuygulandı. Grup I’de süt örneklerinde üreyen bakterilerin 9 adet Koagulaz Negatif Staphylococcus spp. (KNS) (%75), 2 adetStaphylococcus aureus (%16.67) ve 1 adet KNS + Staphylococcus aureus (%8.33) olduğu görüldü. Tedavi sonrasıbakteriyolojik iyileşme oranları sırasıyla %77.77 (7/9), %50 (1/2) ve %100 (1/1) olarak saptandı. Grup II’de süt örneklerindeüreyen bakteriler, 5 adet (%41.66) KNS, 2 adet Staphylococcus aureus (%16.67), 2 adet (%16.67) Streptococcus spp. ve 3adet KNS+Streptecoccus spp. olarak tespit edildi. Bakteriyolojik iyileşme oranları sırasıyla %100 (5/5), %100 (2/2), %0 (0/2)ve % 0 (0/3) olarak saptandı. Grup I ve Grup II’nin toplamda bakteriyolojik iyileşme oranları ise sırasıyla %75 (9/12), %58.33(7/12) olarak belirlendi. Sonuç olarak, meme içi ozon gazı uygulamasının KNS ve Staphylococcus aureus’dan kaynaklanansubklinik mastitislerin tedavisinde oldukça etkin olduğu ve antibiyotiklere alternatif olabileceği, Streptecoccus spp. kaynaklısubklinik mastitlerde ise iyileştirici etkisinin olmadığı kanısına varıldı.
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    The therapeutic potential and molecular mechanism of Alpha-pinene, Gamma-terpinene, and P-cymene against melanoma cells
    (Cell Press, 2024) Acikgul, Funda Cimen; Duran, Nizami; Kutlu, Tuncer; Ay, Emrah; Tek, Erhan; Bayraktar, Suphi
    The purpose of this study is to investigate the potential anticarcinogenic effects of three phytochemicals, namely Alpha-pinene (AP), Gamma-terpinene (GT), and P-cymene (PC), on melanoma cells (A2058 cell line). Additionally, the study aims to explore the synergistic activities of these phytochemicals with Dacarbazine, a chemotherapy drug. To understand the molecular mechanism involved in apoptosis induction in the A-2058 cell line, it was used AO/EB staining for apoptosis detection and cell cycle analysis, monitored through flow cytometry. It also determined the mRNA expression levels of different apoptosis-regulatory genes, including p53, Bax, NF-kB, Bcl-2, Bcl-xl, and caspase-3. The antitumor activities of these phytochemicals and their combinations were investigated in a subcutaneous mouse tumor model. The tumor diameter was 21.4 f 1.1 mm in the Dacarbazine treatment group and 42.4 f 3.1 mm in the control group. The antitumoral activities of AP and PC in the tumor model were similar to those of Dacarbazine. On the other hand, GT exhibited remarkable antitumoral activity, with a 1.75-fold reduction in tumor diameter compared to the Dacarbazine group. When different combinations of phytochemicals and Dacarbazine were used, the GT plus Dacarbazine treatment group was found to have a 3.5- fold reduction in tumor diameter compared to the Dacarbazine group. The tumor diameters in the Dacarbazine, AP plus GT, GT plus Dacarbazine, and AP plus Dacarbazine treatment groups were 21.4 f 1.1, 7.6 f 2.2, 8.6 f 0.5, and 6.2 f 1.9 mm, respectively.