Yazar "Unal, Nilgun" seçeneğine göre listele
Listeleniyor 1 - 10 / 10
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Antibiotic resistance profile of Enterococcus faecium and Enterococcus faecalis isolated from broiler cloacal samples(Scientific Technical Research Council Turkey-Tubitak, 2017) Unal, Nilgun; Askar, Sinasi; Yildirim, MuratThe present study was performed to isolate and identify Enterococcus spp. from broiler cloacal samples to species level, to determine their resistance patterns to various antibiotics, and to detect vancomycin resistance genes. Cloacal samples of broilers collected from slaughterhouses were inoculated in Slanetz and Bartley agars with and without vancomycin (6 mu g/mL). Antibiotic resistance/susceptibility testing of the isolated and identified enterococci was performed by using the disk diffusion test. Multiplex PCR was used to identify the species and to detect vancomycin resistance genes. The majority of the isolated enterococci was Enterococcus faecium (60.43%, n = 142) and Enterococcus faecalis (33.62%, n = 79). E. casseliflavus and E. gallinarum were identified from 8 (3.42%) and 6 (2.56%) isolates, respectively. It was found that 88.9% of the enterococci were resistant to tetracycline and 83.4% of them were resistant to erythromycin. As a result, none of the strains isolated from cloacal samples of broilers carried the vanA and vanB genes. It was observed that 54.9% of E. faecium isolates and 78.4% of E. faecalis isolates were multidrug resistant (resistant to 3 or more antibiotic groups). The lack of vancomycin-resistant Enterococcus among the enterococci isolates was important for public health.Öğe Detection of stapylococcal enterotoxin, methicillin-resistant and Panton-Valentine leukocidin genes in coagulase-negative staphylococci isolated from cows and ewes with subclinical mastitis(Springer, 2012) Unal, Nilgun; Cinar, Oya DoguCoagulase-negative staphylococci (CNS) are the most prevalent mastitis pathogens. However, virulence characteristics of CNS have not been well determined. The presence of genes for enterotoxins (sea-sej), toxic shock syndrome toxin-1 (tst), the exfoliative toxins (eta, etb), Panton-Valentine leukocidin (pvl) and mecA of CNS species isolated from cows and ewes with subclinical mastitis was investigated in this study. A total of 121 CNS (81 cows, 40 ewes) representing 18 different Staphylococci species were examined by PCR, and 38.1% (33 cows and 13 ewes) of CNS isolates had one or more se genes. The difference between percentages for SE toxin genes of CNS strains isolated from cows (40.7%) and ewes (32.5%) was not statistically significant (P>0.05; chi(2) = 0.380). It was found that S. simulans isolates had the highest prevalent se genes. Furthermore, the most common SE gene types was seh-sej. In this study, none of the isolates harbored the toxic shock syndrome toxin gene (tsst) and the exfoliative toxin genes (eta, etb). Five cow (6.17%) and three ewe CNS (7.5%) isolates had mecA gene. Three cow (3.7%) and two ewe CNS (5.0%) isolates had pvl gene. In conclusion, the present study showed that CNS species isolated from cows and ewes could serve as potential reservoir of se, mecA, and pvl genes.Öğe Detection of vancomycin-resistant enterococci in samples from broiler flocks and houses in Turkey(AKADEMIAI KIADO ZRT, 2020) Unal, Nilgun; Bal, Erhan; Karagoz, Alper; Altun, Belgin; Kocak, NadirVancomycin-resistant enterococcus (VRE) is a global threat to public health. Knowledge about the occurrence of vanA-carrying enterococci in broiler and environmental samples is important as antibiotic resistance can be transferred to human bacteria. The aim of this study was to investigate the presence of VRE in broiler cloacal and environmental (house) samples and to genotype the isolates. In this study, 350 swabs were collected from broiler farms. All samples were plated onto enterococcus selective agar containing 6 mg/L vancomycin and 64 mg/L ceftazidime. Minimum inhibitory concentration (MIC) values were determined for vancomycin and teicoplanin. Vancomycin-resistant Enterococcus faecium (VREfm) was isolated from 6 out of 300 (2%) broiler cloacal samples and 13 out of 50 (26%) house samples. All E. faecium isolates had vanA genes. All VREfm isolates (19 isolates) were confirmed to be 95% similar to each other. In conclusion, although 20 years have passed since the ban on avoparcin in Turkey, the present study shows that VREfm isolates are still present in broiler production and especially in broiler houses, and most importantly, a major VREfm clone was isolated from broiler cloacal and house samples.Öğe Development and characterization of polymeric-based nanoparticles for sustained release of amoxicillin - an antimicrobial drug(Taylor & Francis Ltd, 2018) Guncum, Enes; Isiklan, Nuran; Anlas, Ceren; Unal, Nilgun; Bulut, Elif; Bakirel, TulayIn this study, amoxicillin (AMO)-loaded poly(vinyl alcohol)/sodium alginate (PVA/NaAlg) nanoparticles were prepared as a polymer-based controlled release system. The physicochemical properties of the obtained nanoparticles were investigated by XRD, DSC/TGA, particle size analyses and zeta potential measurements. The average particle sizes were in the range from 336.3 +/- 25.66 to 558.3 +/- 31.39 nm with negative zeta potential values from -41.86 +/- 0.55 to-47.3 +/- 2.76 mV. The influences of PVA/NaAlg ratio, span 80 concentration, exposure time to glutaraldehyde (GA) and the drug/polymer ratio on AMO release profiles were evaluated. In vitro drug release studies showed a controlled and pH dependent AMO release with an initial burst effect. XRD patterns and DSC thermograms of AMO-loaded nanoparticles revealed that the drug in the nanoparticles was in amorphous form, which was more stable than the crystalline form. The antibacterial activity of the optimal formulation was also investigated. The minimum inhibitory concentration (MIC) values of this formulation had the comparable antibacterial activity with that of pure AMO. These results indicate that the developed nanoparticles could be a promising candidate drug delivery system for AMO.Öğe Investigation of antimicrobial resistance and extended spectrum beta- lactamase production in Escherichia coli isolates of equine feces origin(Ankara Univ Press, 2016) Ornek, Gamze; Unal, NilgunIn this study, it was aimed to investigate the existence of ESBL and determine the resistance against various antibiotics of E. coli strains isolated from feces examples obtained from racing and jumping horses. One hundred E. coli isolates (racing: 37, jumping: 63) were analysed with 16 antibiotics by using the disc diffusion method and ESBL existence by fenotypic confirmatory test. The antibiotic resistance prevalences were compared between racing and jumping groups of horses. The highest resistance was obtained against tetracycline in both groups with 81.1% (30) in racing horses and 20.6% (13) in jumping horses. ESBL production has been determined in only 6 isolates among 100 E. coli isolates and all 6 ESBL positive isolates were isolated from the racing horses. In conclusion, the resistance prevalences to various antibiotics in racing horses were higher than jumping horses and ESBL production in the isolates from jumping horses was determined. The contamination of these agents in ecosystem could cause a potential risk factor for public health.Öğe Investigation of some toxins genes and methicillin resistance gene in Staphylococcus aureus isolates from cows with subclinical mastitis(Ankara Univ Press, 2013) Unal, NilgunThe aim of this study was to investigate the genes of some staphylococcal enterotoxins and Panton-Valentine leukocidin and methicillin resistance of Staphylococcus aureus strains isolated from subclinical bovine mastitis. In this study, 60 S. aureus isolates were used and the genes were detected by PCR. seg-sei, sej, sec and seh genes were detected in eight (13.33%) isolates, six (10.00%) isolates, four (6.67%) isolates and three (5.00%) isolates, respectively. Sixteen (26.67%) isolates were found to harbor one or more toxin genes. None of the investigated isolates harbored sea, seb, sed, see, and tsst genes, while four (6.6%) isolates and two (3.30%) isolates had Panton-Valentine leukocidin gene and mecA gene, respectively. As a conclusion, it was determined that S. aureus strains isolated from cows with subclinical mastitis could produce enterotoxin and harbor mecA gene. This situtiation could be a potential risk factor for public health.Öğe Isolation of a vanA Positive Enterococcus faecium from Commercial Broiler Farms in Turkey(Kafkas Univ, Veteriner Fakultesi Dergisi, 2010) Unal, Nilgun; Dilik, Zahide; Yildirim, MuratIn this study, the vanA gene indicating Vancomisin Resistance Enterococcus (VRE) was ascertained from swab samples (n=400) collected from commercial broiler farms. VRE was isolated only from a single sample and identified as Enterococcus faecium by the biochemical tests. Minimum inhibitory concentration (MIC) of vancomycin was determined as >256 mu g/ml by E-test. Furthermore, the vanA gene was detected by PCR.Öğe Panton-Valentine leukocidin and some exotoxins of Staphylococcus aureus and antimicrobial susceptibility profiles of staphylococci isolated from milks of small ruminants(Springer, 2012) Unal, Nilgun; Askar, Sinasi; Macun, Hasan Ceyhun; Sakarya, Fatma; Altun, Belgin; Yildirim, MuratThe aims of this study were to determine the existence of pvl gene, some toxin genes, and mecA gene in Staphylococcus aureus strains isolated from sheep milk and to examine antimicrobial resistance profiles in staphylococci from sheep and goats' milk. The milk samples were collected from 13 different small ruminant farms in Kirikkale province from February to August 2009. A total of 1,604 half-udder milk samples from 857 ewes and 66 half-udder milk samples from 33 goats were collected. Staphylococcus spp. were isolated and identified from the samples. Toxin genes and mecA gene among S. aureus strains were determined by PCR. Antimicrobial susceptibility of staphylococci was examined by the disk diffusion method on Mueller-Hinton agar, and interpreted according to the Clinical Laboratory Standards Institute (CLSI) guidelines. The prevalence of subclinical intramammary infection in both ewes and goats was 5.2%. The most prevalent subclinical mastitis agents were coagulase-negative staphylococci and S. aureus with prevalences 2.8% (n:46) and 1.3% (n = 21), respectively. The prevalence of resistances in isolated Staphylococcus spp. to penicilin G, tetracycline, erythromycin, gentamicin, and enrofloxacin were found as 26.9% (18), 7.5% (5), 6.0% (4), 3.0% (2), and 1.5% (1), respectively. Only 3 of the 21 S. aureus ewe isolates (13.4%) were shown to harbor enterotoxin genes being either seh, sej or sec. However, fourteen (66.6%) of the 21 S. aureus isolates had pvl gene while none of the isolates harbored mecA gene. In conclusion, Staphylococci were shown to be the most prevalent bacteria isolated from subclinical mastitis of ewes and goats and these isolates were susceptible to most of the antibiotics. In addition, S. aureus strains isolated from ewes were harboring few staphylococcal enterotoxin genes. However, Panton-Valentine leukocidin produced by S. aureus could be an important virulence factor and contribute to subclinical mastitis pathogenicity.Öğe Phenotypic and genotypic features of Staphylococcus aureus strains isolated from cattle and humans(Ankara Univ Press, 2009) Unal, Nilgun; Istanbulluoglu, ErsinThe aim of this study was to determine susceptibility patterns of S. aureus strains (46 were isolated from bovine milk samples with mastitis, 35 from bovine teat skins, 3 from bovine noses, 3 from caretaker hands and 3 from caretaker noses) to various antibiotics by E-tets and was to define genotypic characteristics of these isolates by plasmid and Pulsed Field Gel Electrophoresis (PFGE) analyses. According to E-test results, the percentages of S. aureus isolates resistant to penicilin G, tetracycline, erythromycin, oxacilline and enrofloxacin were found to be 85.4% (82), 39.6% (38), 5.2% (5), 3.1% (3) and 1.0% (1), respectively. Nine different types were determined in the plasmid analyses of the isolates. In 87 (90.6%) of the isolates, 10 different types of plasmids with the sizes between 1.8-19 kb were determined while no plasmid was detected from the 9 (9.4%) of the isolates. Genetic relationships among S. aureus isolates were performed using PFGE method and 42 distinct PFGE patterns were identified. Strains were assigned as 13 major lineage groups (A, B, C, D, E, F, G, H, I, J, K, L, M) with respect to the genetic relationships. 58.3% (56 samples) of strains were clustered as pulsotype A. In conclusion, according to plasmid analysis and PFGE data, a clone of S. aureus was broadly detected in dairy farms in Kirikkale province.Öğe The Relationship of Coxiella burnetii Seropositivity Between Farm Animals and Their Owners: A Pilot Study(Medwell Online, 2010) Dogru, Aylin Kasimoglu; Yildirim, Murat; Unal, Nilgun; Gazyagci, SerkalQ fever is a zoonotic disease caused by Coxiella burnetii. This study aimed to detect the relationship of C. burnetii seropositivity between farm animal owners and their animals. Blood serums of 20 farm animal owners, 32 cow and 88 sheep were investigated with indirect Immuno Fluorescent Assay (IFA) using C. burnetii phase I and II antigens. Milk samples of the same animals were tested for C. burnetii by PCR. The serological test results of animals and their owners were compared by statistically methods to reveal the interdependence and correlations. The seropositivities of IgG antibodies against C. burnetii were 90.0% for farm animal owners, 53.1% for cows and 63.6% for sheep. All of the animal owners were consuming dairy products made from their. own animals raw milk. However, as shown by PCR results, none of the tested cows and sheep were responsible for shedding of C. burnetii through their milks. Although, there was no correlation between the shedding pattern and serological results of animals, there was a significant correlation between the serological results of animals and their owners for both phase I and II antigens against C. burnetii. There are statistically important relationships between farm animals and their. owners about phase I and phase II IgG titration levels against C. burnetii. Moreover, there was close dependency between the presence of chronic C. burnetii infections in animals and their owners. On the other hand, serological results of milk samples are not in significant correlation with the serologically dependency of animals and their owners.
