George Samonis

Prof. George Samonis


Research Focus & Metrics

Academic Career Length

17Years (2010-Present)

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

Representative Publications

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3 November 2021 in Antibiotics
Verified
Journal Article
Open access
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Stamatis KarakonstantisStamatis Karakonstantis
Stamatis Karakonstantis
PIPetros Ioannou
Petros Ioannou
GSGeorge Samonis
George Samonis
DKDiamantis P Kofteridis
Diamantis P Kofteridis
Antimicrobial combinations are at the moment the only potential treatment option for pandrug-resistant A. baumannii. A systematic review was conducted in PubMed and Scopus for studies reporting the activity of antimicrobial combinations against A. baumannii resistant to all components of the combination. The clinical relevance of synergistic combinations was assessed based on concentrations achieving synergy and PK/PD models. Eighty-four studies were retrieved including 818 eligible isolates. A variety of combinations (n = 141 double, n = 9 triple) were tested, with a variety of methods. Polymyxin-based combinations were the most studied, either as double or triple combinations with cell-wall acting agents (including sulbactam, carbapenems, glycopeptides), rifamycins and fosfomycin. Non-polymyxin combinations were predominantly based on rifampicin, fosfomycin, sulbactam and avibactam. Several combinations were synergistic at clinically relevant concentrations, while triple combinations appeared more active than the double ones. However, no combination was consistently synergistic against all strains tested. Notably, several studies reported synergy but at concentrations unlikely to be clinically relevant, or the concentration that synergy was observed was unclear. Selecting the most appropriate combinations is likely strain-specific and should be guided by in vitro synergy evaluation. Furthermore, there is an urgent need for clinical studies on the efficacy and safety of such combinations.

25 January 2024 in Antibiotics
Verified
Journal Article
Open access
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PIPetros Ioannou
Petros Ioannou
SBStella Baliou
Stella Baliou
GSGeorge Samonis
George Samonis
The development of antimicrobial resistance (AMR), along with the relative reduction in the production of new antimicrobials, significantly limits the therapeutic options in infectious diseases. Thus, novel treatments, especially in the current era, where AMR is increasing, are urgently needed. There are several ongoing studies on non-classical therapies for infectious diseases, such as bacteriophages, antimicrobial peptides, and nanotechnology, among others. Nanomaterials involve materials on the nanoscale that could be used in the diagnosis, treatment, and prevention of infectious diseases. This review provides an overview of the applications of nanotechnology in the diagnosis and treatment of infectious diseases from a clinician’s perspective, with a focus on pathogens with AMR. Applications of nanomaterials in diagnosis, by taking advantage of their electrochemical, optic, magnetic, and fluorescent properties, are described. Moreover, the potential of metallic or organic nanoparticles (NPs) in the treatment of infections is also addressed. Finally, the potential use of NPs in the development of safe and efficient vaccines is also reviewed. Further studies are needed to prove the safety and efficacy of NPs that would facilitate their approval by regulatory authorities for clinical use.

15 March 2024 in Antibiotics
Verified
Journal Article
Open access
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PRPetros Rafailidis
Petros Rafailidis
PPPeriklis Panagopoulos
Periklis Panagopoulos
CKChristos Koutserimpas
Christos Koutserimpas
GSGeorge Samonis
George Samonis
The treatment of Acinetobacter baumannii infections remains a challenge for physicians worldwide in the 21st century. The bacterium possesses a multitude of mechanisms to escape the human immune system. The consequences of A. baumannii infections on morbidity and mortality, as well on financial resources, remain dire. Furthermore, A. baumannii superinfections have also occurred during the COVID-19 pandemic. While prevention is important, the antibiotic armamentarium remains the most essential factor for the treatment of these infections. The main problem is the notorious resistance profile (including resistance to carbapenems and colistin) that this bacterium exhibits. While newer beta lactam/beta-lactamase inhibitors have entered clinical practice, with excellent results against various infections due to Enterobacteriaceae, their contribution against A. baumannii infections is almost absent. Hence, we have to resort to at least one of the following, sulbactam, polymyxins E or B, tigecycline or aminoglycosides, against multidrug-resistant (MDR) and extensively drug-resistant (XDR) A. baumannii infections. Furthermore, the notable addition of cefiderocol in the fight against A. baumannii infections represents a useful addition. We present herein the existing information from the last decade regarding therapeutic advances against MDR/XDR A. baumannii infections.

30 May 2024 in Cancers
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Journal Article
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Andreas G. TsantesAndreas G. Tsantes
Andreas G. Tsantes
EPEleni Petrou
Eleni Petrou
KTKonstantina A. Tsante
Konstantina A. Tsante
Rozeta SokouRozeta Sokou
Rozeta Sokou
Frantzeska G. FrantzeskakiFrantzeska G. Frantzeskaki
Frantzeska G. Frantzeskaki
Argirios TsantesArgirios Tsantes
Argirios Tsantes
Dysregulated hemostasis in cancer patients is associated with various clinical conditions, from thromboembolic complications to disseminated intravascular coagulation. Despite the well-established association between cancer and thromboembolic complications, the mechanisms involved are not completely elucidated. There are several predisposing factors in cancer for increased thrombus generation, such as immobilization and chemotherapy. The term cancer-associated thrombosis (CAT) has been introduced to describe the close bidirectional relationship between cancer and thromboembolic events. Conventional coagulation tests (PT/aPTT) are more accurate in detecting a hypocoagulable rather than a hypercoagulable state; thus, their contribution to CAT management is limited. Traditionally, D-dimer levels have been the most common laboratory study for the evaluation of thrombotic risk. However, D-dimer levels only display a snapshot of the coagulation cascade, and they cannot provide a dynamic evaluation of evolving clot formation. Non-conventional assays, such as viscoelastic methods and microparticle formation are promising tools for the identification of patients at risk for developing CAT. Recent guidelines from the American Society of Clinical Oncology counsel against the estimation of thrombotic risk through a single test and recommend the use of scoring systems that take into account several risk factors. The present review outlines the current insights into the pathophysiological mechanisms of CAT and provides a comprehensive review of the latest advances in the laboratory assessment of CAT and the recent guidelines for the management of patients at risk for developing thromboembolic complications.

13 March 2023 in Vaccines
Verified
Journal Article
Open access
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DBDimitrios Bafaloukos
Dimitrios Bafaloukos
IGIoanna Gazouli
Ioanna Gazouli
CKChristos Koutserimpas
Christos Koutserimpas
GSGeorge Samonis
George Samonis
MRNA vaccines encoding tumor antigens may be able to sensitize the immune system of the host against cancer cells, enhancing antigen presentation and immune response. Since the breakout of the COVID19 pandemic, interest in mRNA vaccines has been accelerating, as vaccination against the virus served as a measure to limit disease spread. Given that immunotherapy has been the cornerstone of melanoma treatment over the last several decades, further innate immunity enhancement by targeted mRNA vaccines could be the next pivotal achievement in melanoma treatment. Preclinical data coming from murine cancer models have already provided evidence of mRNA vaccines’ ability to induce host immune responses against cancer. Moreover, specific immune responses have been observed in melanoma patients receiving mRNA vaccines, while the recent KEYNOTE-942 trial may establish the incorporation of the mRNA-4157/V940 vaccine into the melanoma treatment algorithm, in combination with immune checkpoint inhibition. As the existing data are further tested and reviewed, investigators are already gaining enthusiasm about this novel, promising pathway in cancer therapy.

6 May 2024 in Antibiotics
Verified
Journal Article
Open access
PDF file
APANTRIA PAPAZACHARIOU
ANTRIA PAPAZACHARIOU
NTNikolaos-Renatos Tziolos
Nikolaos-Renatos Tziolos
Stamatis KarakonstantisStamatis Karakonstantis
Stamatis Karakonstantis
PIPetros Ioannou
Petros Ioannou
GSGeorge Samonis
George Samonis
DKDiamantis P Kofteridis
Diamantis P Kofteridis
Acinetobacter baumannii has emerged as a pressing challenge in clinical practice, mainly due to the development of resistance to multiple antibiotics, including colistin, one of the last-resort treatments. This review highlights all the possible mechanisms of colistin resistance and the genetic basis contributing to this resistance, such as modifications to lipopolysaccharide or lipid A structures, alterations in outer membrane permeability via porins and heteroresistance. In light of this escalating threat, the review also evaluates available treatment options. The development of new antibiotics (cefiderocol, sulbactam/durlobactam) although not available everywhere, and the use of various combinations and synergistic drug combinations (including two or more of the following: a polymyxin, ampicillin/sulbactam, carbapenems, fosfomycin, tigecycline/minocycline, a rifamycin, and aminoglycosides) are discussed in the context of overcoming colistin resistance of A. baumannii infections. Although most studied combinations are polymyxin-based combinations, non-polymyxin-based combinations have been emerging as promising options. However, clinical data remain limited and continued investigation is essential to determine optimal therapeutic strategies against colistin-resistant A. baumannii.