Yazar "Çufaoğlu, Gizem" seçeneğine göre listele
Listeleniyor 1 - 7 / 7
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Antibiotic, heavy metal, and disinfectant resistance in chicken, cattle, and sheep origin E. coli and whole-genome sequencing analysis of a multidrug-resistant E. coli O100:H25 strain(Wiley, 2022) Çufaoğlu, Gizem; Cengiz, Görkem; Acar, Bahar Onaran; Yesilkaya, Busra; Ayaz, Naim Deniz; Levent, Gizem; Goncuoğlu, MuammerIn this study, antibiotic, heavy metal, and disinfectant resistance profiles of E. coli and E. coli O157 isolates were determined, and whole-genome sequencing of a multidrug-resistant E. coli O100:H25 strain was reported. A total of 70 E. coli isolated from chicken neck skin and sheep cecum samples, and 32 E. coli O157 strains isolated from cattle carcass, sheep carcass, and slaughterhouse wastewater samples were explored. Minimum inhibitory concentrations (MICs) of one antibiotics, eight heavy metals, and three disinfectants were determined by the broth microdilution method. Twenty of those isolates exhibiting high MIC values against compounds tested were further analyzed by PCR for the presence of relevant resistance genes (n = 42). The majority of the isolates tested were resistant to erythromycin and/or fosfomycin (99% and 78%, respectively) and 89% of the isolates were multidrug-resistant. Among the heavy metals, and disinfectants that were quaternary ammonium compounds (QAC) tested, the highest prevalence of resistance was observed against nickel (71%) and followed by zinc (62%), and N-alkyl-dimethyl-benzyl-ammonium chloride (26%). While bla(AmpC), ermC, murA, and aadA were the most abundant antibiotic resistance genes, rcnA and zntA, and mdfA, sugE (c), and ydg(F) were also commonly observed as heavy metal and disinfectant genes, respectively. Additionally, whole-genome sequencing was performed for a single multidrug-resistant strain (E. coli P91). This strain was identified as serotype O100:H25, and harbored three Inc class plasmids and ant(2 '')-Ia, aph(3 ')-Ia, aph(3 '')-Ib, aph(6)-Id, bla(TEM-1A), dfrA5, mdf(A), sul1, sul2, and tet(A) genes along with the various heavy metal and disinfectant related genes. The findings of the study show that both phenotypic and genotypic antibiotic, heavy metal, and disinfectant resistance are highly prevalent in E. coli isolates that originated from food-producing animals. The use of antimicrobials in food-producing animals needs to be carefully evaluated since the coexistence of antibiotic, heavy metal, and disinfectant resistance genes may result in a coselection that yields the emergence and spread of highly persistent and resistant strains in agricultural settings.Öğe Antimicrobial Effect of Partially Purified Bacteriocins on Pseudomonas aeruginosa(2024) Hacıömeroğlu, Eda; Çufaoğlu, GizemBacteriocins are commonly used in foods to inhibit the growth of spoilage and pathogenic bacteria, thus extending the shelf life of food products. Interest in bacteriocins is increasing because of the increasing tendency of consumers to use healthy, natural and additive-free products in foods. In this study, it was aimed to investigate the control of P. aeruginosa in milk by using partially purified bacteriocins produced from lactic acid bacteria (LAB) strains. Among the 13 reference LAB strains, four strains that showed the highest antimicrobial activity by the agar spot test were selected for bacteriocin production. The bacteriocins were partially purified with 40% ammonium sulfate. The antibacterial activity of bacteriocins on P. aeruginosa strains was determined in arbitrary unit by the well diffusion meth-od. Then, UHT milk samples inoculated with P. aeruginosa and bacteriocin cocktail were stored at +4°C for a week and bacterial counts were performed on the 1st, 3rd, 5th, and 7th days. The LAB strains that displayed the widest clear zones on P. aeruginosa were determined as L. plantarum, L. paraplantarum, L. fermentum and L. pentosus and the antimicro-bial activities of the partially purified bacteriocins of these strains were 640, 640, 160 and 80 AU/ml, respectively. Among tested P. aeruginosa strains, the highest antibacterial effect was observed against P. aeruginosa ATCC 15442 (>18mm). In the milk model, the bacteriocin cocktail caused a decrease of approximately 2 log cfu/ml in the number of bacteria for up to three days and the number remained constant until the end of the seventh day. However, the de-crease in the number of bacteria was not statistically significant (P>0.05). As a result, bacteriocins obtained from Lacto-bacillus strains showed antibacterial effect on P. aeruginosa on agar medium but could not achieve a significant de-crease on the milk. However, bacteriocins, which have generally been proven to efficient on Gram-positive bacteria, have been determined to be effective on P. aeruginosa, a Gram-negative bacterium. Moreover, this study emphasizes that in addition to in-vitro experiments, products to be used for biocontrol purposes in foods are also needed to comple-ment with food models.Öğe Comparison of microbial population of household and commercial kefirs in Ankara, Turkey(2017) Onaran, Bahar; Çufaoğlu, GizemKefir tanelerinde bulunan laktik asit bakterilerinin, asetik asit bakterilerinin ve mayaların kompleks simbiyotik metabolic aktiviteleri sonucu oluşan fermente bir süt ürünü olan kefir, Kafkaslar'da asırlar öncesinde keşfedilmiş olmasına rağmen, sağlığa olan katkılarından ötürü günümüzde de hala pek çok ulus tarafından tüketilmektedir. Kefirin kendine özgü asidik ve hafif alkolik lezzeti bakteri ve mayalardan ileri gelen bir takım Bu popülasyonun kompozisyonu kefirin kaynağına ya da geldiği ülke kökenine göre değişmektedir. Ayrıca kefir tanelerinin süte oranı, oranları, metodu, inkübasyon periyodu ve sıcaklığı, kefir tanelerinin küçültülmesi esnasında hijyen kurallarına uyulup uyulmadığı, tanelerin yıkanması, soğuk muhafaza gibi pek çok etken de mikrobiyal popülasyonu etkileyebilmektedir. Bu çalışmada, Ankara'da tüketilen ticari ve ev yapımı kefirlerin mikrobiyal amaçlanmıştır. Örnekler laktik asit bakterileri, laktokok, maya, enterokok, Enterobacteriaceae ve koliform bakteriler bakımından analiz edilmiştir. Laktik asit bakterileri ve mayalara oranla, ticari kefirlerin ev yapımı kefirlere göre daha fazla laktokok içerdiği tespit edilmiştir. Ayrıca ticari kefir örneklerinden birinde enterokok, bir ev yapımı kefir örneğinde ise koliform bakteri varlığı belirlenmiştirÖğe Emerging details about COVID-19 and chronology of the pandemic in Turkey(2020) Göncüoğlu, Muammer; Cengiz, Görkem; Onaran, Bahar; Ayaz, Naim Deniz; Çufaoğlu, GizemCoronaviruses are found in all mammalian and avian species. Due to its mild infection on upper respiratory tract, this virus was not considered as a serious human pathogen until the outbreaks of SARS-CoV and MERS-CoV in 2002 and 2012, respectively. Recently the third and the biggest outbreak of coronavirus “COVID-19” or “SARS-CoV-2” has erupted and the world is now in a struggle to combat this disease. Although everything has not yet been fully clarified about this new type of virus, the data obtained from the studies conducted so far provides guidance on how to deal with SARS-CoV-2. In this context, this review provides information about pathogenesis, clinical symptoms, presence in animals, potential transmission routes of SARS-CoV-2 as well as the detection methods used in the world and Turkey.Öğe Listeria monocytogenes risk associated with chicken at slaughter and biocontrol with three new bacteriophages(Wiley, 2019) Çufaoğlu, Gizem; Ayaz, Naim DenizThe aim of this study was to isolate Listeria monocytogenes from chicken neck skins and lytic bacteriophages from poultry slaughterhouse wastewaters, and following the characterization of the isolates, biocontrol of L. monocytogenes was investigated on chicken drumsticks with the isolated phages. L. monocytogenes prevalence was detected 12.3% in the chicken samples and the dominant serotype was determined as 1/2a (92.5%). Expression levels of major virulence genes were revealed by real-time RT-PCR. Ten different DNA profiles were detected by ERIC-PCR fingerprinting. According to the MIC results, LM-P75 was defined as MDR by showing resistance to antibiotics in six different groups. Besides, five lytic listeriophages were isolated from wastewaters and treated with Cla1 and Sac1. Taking EoP, TEM, in vitro, and in vivo analyses results into consideration, three bacteriophages were used for the biocontrol assay. The application of the bacteriophages on drumsticks achieved a reduction up to 3.3 log CFU/ml in L. monocytogenes count in 3 hr of incubation at 4 degrees C. Practical applications Our results showed that in spite of the developments in hygiene practices during slaughtering, chicken meat is still a potential source for L. monocytogenes. On the other hand, the phage cocktail that used in this study can be an effective tool to reduce L. monocytogenes in chicken carcasses at final wash or at cooling step in poultry slaughtering process, as well as in decontamination of chicken meat parts.Öğe Prevalence, Serotype Diversity and Antibiotic Resistance of Salmonella Among Poultry Meat and Eggs in Turkiye: A Meta-analysis(Galenos Publ House, 2023) Çufaoğlu, Gizem; Ambarcıoğlu, Pınar; Derinoz, Aşkın Nur; Ayaz, Naim DenizPoultry is a well-known reservoir for Salmonella, and therefore numerous outbreaks have been reported among poultry meat products and eggs. This study is aimed at determining the pooled prevalence, serotype diversity and antibiotic resistance profiles of Salmonella among poultry meat and eggs sold in Turkiye. For this purpose, international (Web of Science and PubMed) and national (ULAKBIM TR Index) electronic databases were searched using based on relevant keywords in English and Turkish, and out of 1,818 articles, 41 were deemed eligible for inclusion in this meta-analysis. The random effects model was accepted when a substantial heterogeneity was obtained according to Q statistics and the I2 value, however the fixed effects model was assumed valid in the opposite case. The pooled prevalence of Salmonella in chicken parts, chicken carcasses, chicken giblets and eggs were 24.4% [95% confidence interval (CI)=17.8-32.6], 21.9% (95% CI=14.0-32.7), 20.1% (95% CI=10.7- 34.6) and 4.8% (95% CI=1.7-13.3), respectively. Salmonella Enteritidis was the most common serotype among eggs, chicken parts and chicken carcasses with the rates of 22.4% (95% CI=3.6-69.3), 19.0% (95% CI=3.3-61.6) and 5.8% (95% CI=2.2-14.4), respectively. The highest pooled antibiotic resistance prevalence of Salmonella spp., regardless of food type, was found in tetracycline (73.9%, 95% CI=51.0-88.5) (p<0.041) and ampicillin (31.5%, 95% CI=20.7-44.6). The high-pooled prevalence of the organism emphasized the potential threat Salmonella poses to public health, and also antibiotic resistance data revealed that the use of tetracyclines, quinolones and penicillin in poultry livestock should be restricted. These results will be of great use in the future epidemiological surveillance of Salmonella spp. presence and antibiotic resistance among poultry meat and eggs in Turkiye.Öğe Sensitizing And Control Of Colistin-Resistant E. Coli O157:H7 with Bacteriophage Application(2021) Çufaoğlu, Gizem; Ayaz, Naim DenizIn these days that we are drifting into the post-antibiotic era, antibiotics called \"last-resort\" are begun to be used more frequently. Colistin is one of the last-resort antibiotics that act on Gram-negative bacteria. The aim of the study was to investigate antibiotic re-sensitization effect of lytic bacteriophages on colistin resistant E. coli O157:H7 in-vitro. In the study, four E. coli O157:H7 isolates (encoded 25KA, 44RA, 120RA, and 168KA) were included. These isolates had different features such as harboring some of the mcr genes but not showing resistance to colistin, or demonstrating resistance to colistin without carrying any mcr genes. A lytic bacteriophage cocktail was prepared with three Myoviridae family member phages. In order to determine the effect of lytic bacteriophage application on the colistin resistance of E. coli O157:H7 strains before, during and after bacteriophage treatment, minimum inhibitory concentrations (MIC) of the isolates were determined by broth microdilution method. The results were interpreted according to EUCAST. According to the results, up to 3.6 log cfu/ml reductions in colistin-resistant E. coli O157:H7 were detected within 6h incubation at 23°C. Colistin and phage combination showed synergistic effect. While strains 25KA and 168KA became susceptible to colistin, 44GA and 120RA were totally eliminated. The survivors of the phage treatment also became sensitive to colistin. Phage-resistant mutants of 25KA and 168KA showed susceptibility to colistin (1 µg/ml and 0.5 µg/ml, respectively). In addition, 44GA and 120GA remained susceptible. The findings of this study highlight that in addition to taking advantage of the lytic activity of phages in biocontrol area, phages also play a major role in re-sensitization to a last-resort antibiotic like colistin. The results show the synergy between phage–antibiotic combination treatment and give the promising idea that this approach has the potential to extend the effective lifetime of antibiotics.
