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Öğe Analysis of an outbreak of echinocandin-resistant clonal Candida parapsilosis complex harbouring ERG11Y132F and FKS1S656P mutations(W B Saunders Co Ltd, 2026) Kapmaza, M.; Dogan, O.; Irkoren, P.; Cam, K.; Tanriverdi, E. S.; Genc, Z.; Tas, E.Aim: We aimed to analyse echinocandin-resistant (ECR) Candida parapsilosis complex candidaemia episodes. Methods: A retrospective cohort study was conducted at Koc, University Hospital from 1st January 2018 to 30th March 2022, during the COVID-19 pandemic. A total of 307 candidaemia isolates were obtained from 249 patients. A total of 272 episodes had monocandidaemia, while 16 episodes had poly-candidaemia. Antifungal susceptibility with broth microdilution with environmental microbiological sampling were obtained. Sequencing and amplification of the resistance genes with genotyping were carried out, and pulse field gel electrophoresis was performed in the isolates. Results: Of the 272 isolates that caused mono-candidaemia, 139 (51.1%) were identified as C. parapsilosis complex, with 64 (46%) demonstrating micafungin resistance. The isolates yielded Y132F mutation in the ERG11, and S656P mutation in the FKS1 genes, primarily genotypes A and A1. The 30-day mortality rates were 51.6% (33/64) for ECR C. parapsilosis complex, 38.9% (14/36) for fluconazole-resistant C. parapsilosis complex, and 35.9% (14/ 39) for fluconazole-susceptible C. parapsilosis complex. Environmental cultures showed that 23 of 60 samples yielded ECR C. parapsilosis complex, predominantly from interior parts and handles of infusion pumps used in oncology wards with a total clonal similarity with the clinical isolates. Conclusions: This is the first report of the FKS1S656P mutation in ECR C. parapsilosis complex isolates from Turkey, and it highlights a significant outbreak associated with an unnoticed gap in cleaning of the interior parts of infusion pumps. Enhanced cleaning protocols, combined with on-site feedback, resulted in no new cases within the next 2 months.Öğe Carriage of antimicrobial resistance genes in Escherichia coli of bovine origin(Polska Akad Nauk, Polish Acad Sciences, Univ Warmia & Mazury Olsztyn, 2024) Ozbey, G.; Tanriverdi, E. S.; Acik, M. N.; Kalin, R.; Otlu, B.; Zigo, F.The present study aimed to search for the presence of the plasmid-mediated antimicrobial resistance genes in 106 Escherichia coli (E. coli) isolates from a total of 240 fresh fecal samples collected from 12 private cattle farms in Bingol province of East Turkey from November 2021 to January 2022. In those colistin-resistant E. coli (mcr-1 to-9), the major carbapenemase ( bla OXA-48 , bla NDM-1 , bla IMP, bla VIM, and bla KPC ), beta-lactamase (blaTEM-1, bla CTX-M and bla SHV-1 ) and OXA-48 like beta- lactamase ( bla OXA-162 , bla OXA-163 , bla OXA-181 , bla OXA-204 and bla OXA-232 ) resistance genes were searched for determined a multiplex polymerase chain reaction (PCR) method and Next-generation sequencing (NGS)- PCR Amplicons with Nanopore Technology. Only the mcr-4 gene was found in one isolate and the remaining genes (mcr-1-9) were not shown in all E. coli isolates from cattle. The minimal inhibitory concentration (MIC) to colistin was detected in mcr-4 positive E. coli isolates using broth microdilution. We assessed the antimicrobial susceptibilities of mcr-4 positive E. coli isolates using the Kirby-Bauer disk diffusion method. E coli isolate was detected as negative for carbapenemase and OXA-48 like beta-lactamase resistance genes and positive for beta-lactamase. In addition, E. coli isolates carrying mcr-4 were more resistant to colistin. Antimicrobial susceptibility testing using the disk diffusion assay indicated that all 106 E. coli isolates (100%) were sensitive to AMK, 105 E. coli isolates (99.1%) exhibited sensitivity to imipenem, meropenem and doripenem, and 1 E. coli isolate (0.9%) had intermediate resistance to imipenem, meropenem and doripenem; It was observed that all strains (100%) were resistant to cefotaxime. E. coli isolates are resistant to ampicillin (95.3%), amoxicillin/clavulanic acid (95.3%), cefepime (14.2%), cefixime (19.8%), cephalexin (74.5%), gentamicin (42.5%), kanamycin (37.7%), streptomycin (69.8%), tetracycline (80.2%), ciprofloxacin (60.4%), norfloxacin (13.2%), chloramphenicol (59.4%) and trimethoprim/sulfamethoxazole (68.9%). When we investigated the sequence in the Blast database, the genome of the E. coli isolate indicated high similarity with the mcr-4 sequences. To our knowledge, this is the first report investigating on the mcr-4 gene in E. coli identified from cattle in Turkey. Our results highlighted that cattle might be a potential risk in transmitting mcr genes.Öğe The effect of Nateglinide and Octreotide on follicular morphology and free radical scavenging system in letrazole-induced rat model of PCOS(Verduci Publisher, 2022) Kirici, P.; Kaplan, S.; Annac, E.; Tanriverdi, E. S.; Cagiran, F. T.; Kali, Z.; Mavral, N.OBJECTIVE: To investigate the ef-fects of octreotide and nateglinide on ovarian folli-cle count, ovarian tissue damage, biochemical pa-rameters and free radical scavenging system in le-trazole-induced rat model of PCOS. MATERIALS AND METHODS: Forty-two female Sprague-Dawley rats were divided into six groups. Group 1 (Control Group): after localizing the ova-ries and the uterine horns, the abdominal wall was closed without any surgical procedure. Group 2 (PCOS Group): PCOS was induced by administrat-ing Letrozole orally for 21 successive days. At the end of 21 days, rats underwent ovarian biopsies. The experimental PCOS model was considered successful in the presence of atretic follicles with-out granulosa cell stratification. Group 3 (PCOS + Nateglinide Group): Nateglinide was administered by oral dropper for 30 days to the rats in which PCOS model was created. Group 4 (Nateglinid only Group): 30 days of NG was applied to the rats with-out PCOS. Group 5 (PCOS+Octreotide Group): 0.1 mg/kg/day Octreotide was given intraperitoneally for 4 weeks to the rats in which PCOS model was created. Group 6 (Octreotide only Group): animals without PCOS were given 0.1 mg/kg/day Octreotide. Bilateral oophorectomy was performed and blood samples were collected from all groups at the end of the treatment. Ovarian tissue was stained immu-nohistochemically with TLR-4 in addition to con-ventional staining. In addition to follicle classifica-tion, ovarian damage was graded. Serum insulin, FSH and LH, TNF-alpha, IL-6, SHBG, SOD, IGF-1, MDA and GSH levels were also measured. RESULTS: The cystic and degenerated follicle density of PCOS group was high compared with the other groups. Both cystic and degenerated fol- licles were significantly reduced in PCOS+NG and PCOS+OC groups compared to PCOS group. There was no difference between the groups in terms of serum LH, FSH and insulin levels (p > 0.05). Serum testosterone level was significantly higher in the PCOS group compared to the other groups (p < 0.01). Adding OC or NG to PCOS groups did not cause significant changes in testosterone levels. TNF-alpha and IL-6 levels were high in PCOS group (p < 0.03). IGF-1 and MDA levels were higher in PCOS than in other groups (p < 0.03, p < 0.01 respectively). Adding OC or NG to the treatment normalized IGF-1 and MDA levels. Serum GSH levels were significantly lower in the PCOS group (p < 0.05). Adding NG to the treatment increased GSH levels. CONCLUSIONS: Both NG and OCT reverses atretic and degenerate follicle damage due to PCOS through TLR-4, antioxidant and anti-inflammatory pathways.Öğe Investigation of Antimicrobial Activities and Molecular Docking Studies of Synthesized Sulfonamide Compounds(Springer, 2023) Ozbey, G.; Tanriverdi, E. S.; Senkal, B. F.; Korkmaz, B.; Erkan, S.; Bulut, N.; Zigo, F.Sulfonamides are commonly used worldwide. In this study, several sulfonamide compounds such as N-(4-acetylphenyl)-4-methylbenzenesulfonamide (PSASF), N-(3-acetylphenyl)-4-methylbenzenesulfonamide (PSASF-1), 1-tosyl-1H-imidazole (PSASF-x), 4-methyl-N-(pyridin-4-yl) benzenesulfonamide (PSASF-2), and 1-ethyl-4-tosylpiperazine (PSASF-3) have been synthesized, with antibacterial activities against Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, and Staphylococcus aureus ATCC 29213 have been evaluated. Antibacterial properties of drugs were studied in depth using molecular docking research. In addition, the synthesized compounds were characterized using spectral analysis. Antibacterial activities of synthesized derivates were determined against E. coli, P. aeruginosa, and S. aureus with minimum inhibitory concentration (MIC) by using the broth microdilution method. All prepared compounds exhibited significant antibacterial activity against S. aureus, E. coli, and P. aeruginosa. The MIC value for E. coli and P. aeruginosa was determined as 256 mu g/mL. MIC against S. aureus was observed to be 256 and 512 mu g/mL for the PSASF compound and the other compounds respectively. Results of the current study revealed that four of the five compounds had weaker antibacterial activity against S. aureus at a concentration of 512 mu g/mL. However, the MIC values from our experiments are significantly higher in comparison with the reference drugs such as amoxicillin, ciprofloxacin, meropenem, and vancomycin in E. coli and S. aureus. On the other hand, in a comparison of the synthesized compounds with reference drugs in P. aeruginosa, no statistical difference was demonstrated. Antibacterial activity of the produced derivates was likewise an agreement with regard to the molecular docking and the laboratory results.Öğe Prevalence and antimicrobial resistance profiles of bacterial pathogens associated with subclinical mastitis and dairy farm environments(Polska Akad Nauk, Polish Acad Sciences, Univ Warmia & Mazury Olsztyn, 2025) Ozbey, G.; Tanriverdi, E. S.; Zigo, F.This study investigated the prevalence and antimicrobial resistance (AMR) profiles of bacterial pathogens linked to subclinical mastitis in dairy cows, as well as their occurrence in milk, faecal, and environmental samples collected in eastern Turkey between February and May 2024. A total of 2,400 milk samples were collected from 600 cows affected with subclinical mastitis, along with 292 rectal faecal samples, 150 raw milk samples consumed by the public, and hand and fecal samples obtained from animal breeders in 25 cattle enterprises. In addition, environmental samples such as water, soil, feed, and bedding (five samples per enterprise), were collected. Bacterial isolates cultured from all samples were identified using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) mass spectrometry. Of the 600 cows examined, 292 (48.6%) were CMT-positive, and bacterial growth was detected in 261 (89.7%) of these samples. The predominant isolates were coagulase-negative staphylococci (CoNS, 30.8%), Staphylococcus aureus (19.5%), Escherichia coli (8.9%), and Aerococcus viridans (5.8%). Antimicrobial susceptibility of S. aureus and CoNS against 15 antibiotics and E. coli against 17 antibiotics was assessed using the disc diffusion method, and the mecA gene was screened by PCR. Among 121 E. coli isolates, no mcr, carbapenemase, or beta-lactamase genes were detected by multiplex PCR. Tetracycline resistance was highest among E. coli isolates, particularly in milk samples from mastitic cows, rectal fecal samples, unpasteurised cow's milk, farmer's feces, soil, and feed, while resistance to amikacin, cefepime, cefoxitin, cephalexin, ertapenem, and norfloxacin remained lower. No resistance was observed against kanamycin. The mecA gene was identified in three S. aureus isolates (3/57, 5.3%): two from cows affected with subclinical mastitis and one from a farmer's hand. These findings highlighted the prevalence of major bacterial pathogens, potential therapeutic challenges and public health risks associated with the presence of AMR bacteria and raw milk consumption.Öğe Transmission of Staphylococcus aureus from an outpatient to an inpatient: implications for infection control(W B Saunders Co Ltd, 2026) Tanriverdi, E. S.; Yakupogullari, Y.; Memisoglu, F.; Otlu, B.[No abstract available]
