Georgios A Delis

Prof. Dr. Georgios A Delis

orcid

Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
13 August 2021 in Animals
Verified
Journal Article
Open access
PDF file
DPDimitrios Eleftherios Papadopoulos
Dimitrios Eleftherios Papadopoulos
Evanthia PetridouEvanthia Petridou
Evanthia Petridou
KPKonstantinos Papageorgiou
Konstantinos Papageorgiou
Ioannis A GiantsisIoannis A Giantsis
Ioannis A Giantsis
GDGeorgios A Delis
Georgios A Delis
SKSpyridon Kritas
Spyridon Kritas
The purpose of this research was to characterize the antibiotic resistance patterns of Campylobacter spp. isolated from commercial farrow to finish farms in Greece, and analyze the relevant molecular resistance mechanisms among the resistant Campylobacter isolates. Susceptibility testing to five different classes of antibiotics was performed in 100 C. coli and 100 C. jejuni, previously isolated and identified. All isolates were found susceptible to meropenem. Very high rates of resistance were recorded for tetracyclines (84.5%), medium rates of resistance were recorded regarding quinolones (23%), and low and very low rates of resistance were identified for macrolides such as erythromycin and aminoglycosides (12% and 4%, respectively). Only 12.5% of the Campylobacter isolates displayed MDR. Regarding the molecular mechanisms of resistance, all ciprofloxacin resistant isolates hosted the mutant type Thr-86-Ile region of the quinolone resistance-determining region (QRDR) of the gyrA gene. In all erythromycin resistant isolates, the transitional mutations A2075G and A2074C in the 23S rRNA gene were only amplified. Molecular screening of tetracycline resistance genes indicated that the vast majority of Campylobacter isolates (92.3%) were positive for the tet(O) gene. In summary, these findings and especially the very high and medium rates of resistance for tetracyclines and fluroquinolones, respectively recommend that a continuous monitoring of Campylobacter isolates susceptibility in combination with the proper use of antimicrobials in livestock production is of great importance for public health.

12 June 2023 in Sustainability
Verified
Journal Article
Open access
PDF file
AXAnna Xexaki
Anna Xexaki
DPDimitrios K Papadopoulos
Dimitrios K Papadopoulos
Maria Vasileiou AlvanouMaria Vasileiou Alvanou
Maria Vasileiou Alvanou
Ioannis A GiantsisIoannis A Giantsis
Ioannis A Giantsis
KPKonstantinos Papageorgiou
Konstantinos Papageorgiou
Evanthia PetridouEvanthia Petridou
Evanthia Petridou
The use of antimicrobials is beneficial for livestock health; however, their overuse and misuse may increase resistance to these compounds. Thus, the aim of the present study was the phenotypic and molecular examination of the presence of Escherichia coli antibiotic-resistant strains in broiler and laying hen farms. The resistance of E. coli strains was examined against various antibiotics, including several families of compounds such as penicillin class medications (ampicillin), cephalosporins (cefotaxime, cefoxitin, cefpodoxime and ceftazidime), sulfonamides (co-trimoxazole), quinolones (enrofloxacin and nalidixic acid), aminoglycosides (gentamicin), β-lactams (imipenem), aminoglycoside (streptomycin), and polymyxin (colistin). In total, 106 strains were investigated, sampled during the years 2016–2019 from 91 poultry farms, including 75 broiler farms and 16 laying hen farms, originating from three Regional Units in Greece. The examined isolates revealed the highest resistance rates to sulfamethoxazole (81.1%), nalidixic acid (73.6%), tetracyclin (70.8%), and streptomycin (70.8%). On the other hand, the resistance of the isolates to third generation cephalosporins was found to be at lower levels for ceftazidime (2.8%), ceftriaxone (3.7%) cefoxitin (4.7%), and cefotaxime (4.7%). Phenotypic tests showed that 13.6% and 10.2% of the isolates produced ESBL, while 2.7% and 1% produced AmpC b-lactamase, for broiler and laying hens, respectively. The prevalence of the mcr-1 gene was found to be 22.7%, detected only in broiler isolates. Based on our results, E. coli antibiotic resistance represents a critical control point in poultry production that, apart from farm animals, may affect public health as well.

31 August 2025 in Nutrients
Verified
Journal Article
Open access
PDF file
IKIoannis Konstantinidis
Ioannis Konstantinidis
Sophia TsokkouSophia Tsokkou
Sophia Tsokkou
Eleni GavriilakiEleni Gavriilaki
Eleni Gavriilaki
GDGeorgios A Delis
Georgios A Delis
Theodora PapamitsouTheodora Papamitsou
Theodora Papamitsou
Background/Objectives: Systemic toxicities to key organs like the heart, liver, and kidneys impair the efficacy of chemotherapy in cancer treatment. These toxicities are caused by oxidative stress, inflammation, mitochondrial malfunction and ferroptosis, causing clinical morbidity and possibly impaired adherence to treatment. This review, also, examines how magnesium, selenium, zinc and vitamin D protect against chemotherapy-induced cardiotoxicity, hepatotoxicity and nephrotoxicity. Methodology: A complete literature search of PubMed (MEDLINE), Scopus, Cochrane Library and Embase was used to synthesize data till 29 June 2025. Studies included randomized and non-randomized trials, cohort studies, case series (≥3 patients), and relevant systematic reviews. To contextualize pathways, preclinical in vivo and in vitro studies were studied independently. Patients undergoing systemic chemotherapy and magnesium, selenium, zinc or vitamin D therapies were eligible. Supplementation’s safety and organ-specific toxicity were investigated. Results: Magnesium protected against cisplatin-induced nephrotoxicity via modulating renal transporters and oxidative defenses across chemotherapy regimens. Selenium supplementation has strong antioxidant and anti-inflammatory characteristics, especially in avoiding cardiac and hepatic injury, although its nephroprotective potential was formulation-dependent. Zinc’s activity was connected to metallothionein-mediated redox stabilization, inflammatory regulation, and cardiac and hepatic resilience. Vitamin D and its analogs reduced cardiotoxicity and nephrotoxicity through mitochondrial preservation and immunomodulatory signaling. Conclusions: To date, magnesium, selenium, zinc, and vitamin D have been shown to reduce chemotherapy-related organ toxicities. Preclinical studies are promising, but randomized clinical trials are needed to prove therapeutic effectiveness and oncologic safety.

31 October 2022 in Gels
Verified
Journal Article
Open access
PDF file
Eleftherios AndriotisEleftherios Andriotis
Eleftherios Andriotis
PMParaskevi Kyriaki Monou
Paraskevi Kyriaki Monou
George KomisGeorge Komis
George Komis
Nikolaos BouropoulosNikolaos Bouropoulos
Nikolaos Bouropoulos
CRChristos Ritzoulis
Christos Ritzoulis
DFDimitrios Fatouros
Dimitrios Fatouros
Medium Chain Triglyceride (MCT) oil was successfully combined with Glyceryl Monostearate (GMS) and Glyceryl Monoolein (GMO) to form oleogels that were subsequently whipped to form stable oleofoams. The co-crystallization of GMS and GMO at a ratio of 20:1, 20:2.5, and 20:5 within MCT oil was studied through Differential Scanning Calorimetry (DSC), X-ray Diffraction analysis (XRD), rheological analysis, Fluorescence Recovery after Photobleaching (FRAP), Fourier Transform Infrared Spectroscopy (FTIR), and polarized microscopy. The addition of 5% GMO resulted in the production of more stable oleogels in terms of crystal structure and higher peak melting point, rendering this formulation suitable for pharmaceutical applications that are intended to be used internally and those that require stability at temperatures close to 40 °C. All formulations were whipped to form oleofoams that were evaluated for their storage stability for prolonged period at different temperatures. The results show that oleofoams containing 5% MGO retained their foam characteristics even after 3 months of storage under different temperature conditions.

1 March 2022 in Animals
Verified
Journal Article
Open access
PDF file
Georgios PapadopoulosGeorgios Papadopoulos
Georgios Papadopoulos
AWAlexandra Wealleans
Alexandra Wealleans
GDGeorgios A Delis
Georgios A Delis
GJGeert Janssens
Geert Janssens
MBMauro di Benedetto
Mauro di Benedetto
PFPASCHALIS FORTOMARIS
PASCHALIS FORTOMARIS
The objective of the present study was to evaluate the effects of dietary supplementation of lysolecithin in sows’ diets during the last three weeks of the gestation period and throughout the lactation period on performance and metabolic parameters. In total 60 sows were allocated to two treatments: (a) CG (control group): the sows were fed commercially control diets; (b) LLG (lysolecithin group): the sows were fed the control diets supplemented with 750 g/t of feed supplemented with lysolecithin (Lysoforte Booster DryTM, Kemin Europa N.V., Herentals, Belgium). Backfat was lower in LLG than CG at end of gestation and at weaning (p = 0.030 and 0.044, respectively), while the CG sows mobilized more backfat between day 14 to weaning (p = 0.006). Litter weight at weaning was higher in the LLG (p = 0.027). Fasted glucose levels at day 14 of lactation tended to be lower in LLG compared to CG (p = 0.074). Urea concentrations were higher in LLG than CG at day 14 (p = 0.002). Lysolecithin supplemented sows compared to the control mobilized less tissue during lactation to support lactation demands. In conclusion, lysolecithin supplementation in sows resulted in improved litter weight at weaning without an excessive catabolism of backfat tissue, most probably due to an efficient nutrient utilization, which warrants further investigation.

27 June 2023 in Diagnostics
Verified
Journal Article
Open access
PDF file
ATALEXANDROS TOSKAS
ALEXANDROS TOSKAS
SMStefanos Milias
Stefanos Milias
GDGeorgios A Delis
Georgios A Delis
SMSoultana Meditskou
Soultana Meditskou
ASAntonia Sioga
Antonia Sioga
Theodora PapamitsouTheodora Papamitsou
Theodora Papamitsou
Interleukins are considered to be potential therapeutic targets that can alter the prognosis and disease progression of IBD. IL-21 has proven to be involved in effector Th1, Th2 and Th17 responses. Similarly, IL-33, a newly identified cytokine, has been shown to control the Th1 effector response and the action of the colonic Tregs in animal models of colitis and patients with IBD. In this retrospective study, we have studied the expression of these interleukins, using immunohistochemistry, in 121 patients with moderate to severe IBD before and after treatment with biologics. The results were statistically processed using SPSSTM. Increased IL-21 expression was found in the UC and CD groups versus the controls. The IL-33 expression was found to be increased in the post-treatment UC and CD groups, suggesting a protective role of this interleukin against bowel inflammation. The IL-33 expression post-treatment was reversely correlated with the activity index score in CD patients, suggesting a better response to treatment in patients with higher IL-33 mucosa levels. This is the first immunohistochemical study of the expression of those interleukins in bowel mucosa before and after treatment with biologics. These data support a possibly promising future use of these interleukins as biomarkers of severe disease and response to treatment and as potential therapeutic targets for novel monoclonal antibodies.