Dimitris Kalles

Prof. Dimitris Kalles

School of Science and Technology, Hellenic Open University, Patra, Greece
orcid

Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

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

Representative Publications

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24 February 2023 in Antibiotics
Verified
Journal Article
Open access
PDF file
ASAikaterini Sakagianni
Aikaterini Sakagianni
CKChristina Koufopoulou
Christina Koufopoulou
GEORGIOS FERETZAKISGEORGIOS FERETZAKIS
GEORGIOS FERETZAKIS
Dimitris KallesDimitris Kalles
Dimitris Kalles
VVVassilios S. Verykios
Vassilios S. Verykios
GFGeorgios Fildisis
Georgios Fildisis
Machine learning (ML) algorithms are increasingly applied in medical research and in healthcare, gradually improving clinical practice. Among various applications of these novel methods, their usage in the combat against antimicrobial resistance (AMR) is one of the most crucial areas of interest, as increasing resistance to antibiotics and management of difficult-to-treat multidrug-resistant infections are significant challenges for most countries worldwide, with life-threatening consequences. As antibiotic efficacy and treatment options decrease, the need for implementation of multimodal antibiotic stewardship programs is of utmost importance in order to restrict antibiotic misuse and prevent further aggravation of the AMR problem. Both supervised and unsupervised machine learning tools have been successfully used to predict early antibiotic resistance, and thus support clinicians in selecting appropriate therapy. In this paper, we reviewed the existing literature on machine learning and artificial intelligence (AI) in general in conjunction with antimicrobial resistance prediction. This is a narrative review, where we discuss the applications of ML methods in the field of AMR and their value as a complementary tool in the antibiotic stewardship practice, mainly from the clinician’s point of view.

31 January 2020 in Antibiotics
Verified
Journal Article
Open access
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GEORGIOS FERETZAKISGEORGIOS FERETZAKIS
GEORGIOS FERETZAKIS
ELEvangelos Loupelis
Evangelos Loupelis
ASAikaterini Sakagianni
Aikaterini Sakagianni
Dimitris KallesDimitris Kalles
Dimitris Kalles
MMMaria Martsoukou
Maria Martsoukou
KAKonstantinos Alexiou
Konstantinos Alexiou
Hospital-acquired infections, particularly in the critical care setting, have become increasingly common during the last decade, with Gram-negative bacterial infections presenting the highest incidence among them. Multi-drug-resistant (MDR) Gram-negative infections are associated with high morbidity and mortality with significant direct and indirect costs resulting from long hospitalization due to antibiotic failure. Time is critical to identifying bacteria and their resistance to antibiotics due to the critical health status of patients in the intensive care unit (ICU). As common antibiotic resistance tests require more than 24 h after the sample is collected to determine sensitivity in specific antibiotics, we suggest applying machine learning (ML) techniques to assist the clinician in determining whether bacteria are resistant to individual antimicrobials by knowing only a sample’s Gram stain, site of infection, and patient demographics. In our single center study, we compared the performance of eight machine learning algorithms to assess antibiotic susceptibility predictions. The demographic characteristics of the patients are considered for this study, as well as data from cultures and susceptibility testing. Applying machine learning algorithms to patient antimicrobial susceptibility data, readily available, solely from the Microbiology Laboratory without any of the patient’s clinical data, even in resource-limited hospital settings, can provide informative antibiotic susceptibility predictions to aid clinicians in selecting appropriate empirical antibiotic therapy. These strategies, when used as a decision support tool, have the potential to improve empiric therapy selection and reduce the antimicrobial resistance burden.

31 July 2021 in Healthcare Informatics Research
Verified
Journal Article
Open access
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GEORGIOS FERETZAKISGEORGIOS FERETZAKIS
GEORGIOS FERETZAKIS
ASAikaterini Sakagianni
Aikaterini Sakagianni
ELEvangelos Loupelis
Evangelos Loupelis
Dimitris KallesDimitris Kalles
Dimitris Kalles
NSNikoletta Skarmoutsou
Nikoletta Skarmoutsou
EDEvangelos Dimitrellos
Evangelos Dimitrellos
Objectives: In the era of increasing antimicrobial resistance, the need for early identification and prompt treatment of multi-drug-resistant infections is crucial for achieving favorable outcomes in critically ill patients. As traditional microbiological susceptibility testing requires at least 24 hours, automated machine learning (AutoML) techniques could be used as clinical decision support tools to predict antimicrobial resistance and select appropriate empirical antibiotic treatment.Methods: An antimicrobial susceptibility dataset of 11,496 instances from 499 patients admitted to the internal medicine wards of a public hospital in Greece was processed by using Microsoft Azure AutoML to evaluate antibiotic susceptibility predictions using patients’ simple demographic characteristics, as well as previous antibiotic susceptibility testing, without any concomitant clinical data. Furthermore, the balanced dataset was also processed using the same procedure. The datasets contained the attributes of sex, age, sample type, Gram stain, 44 antimicrobial substances, and the antibiotic susceptibility results.Results: The stack ensemble technique achieved the best results in the original and balanced dataset with an area under the curve-weighted metric of 0.822 and 0.850, respectively.Conclusions: Implementation of AutoML for antimicrobial susceptibility data can provide clinicians useful information regarding possible antibiotic resistance and aid them in selecting appropriate empirical antibiotic therapy by taking into consideration the local antimicrobial resistance ecosystem.

26 May 2022 in World Journal of Urology
Verified
Journal Article
Closed access
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LTLazaros Tzelves
Lazaros Tzelves
LLLazaros Lazarou
Lazaros Lazarou
GEORGIOS FERETZAKISGEORGIOS FERETZAKIS
GEORGIOS FERETZAKIS
Dimitris KallesDimitris Kalles
Dimitris Kalles
PMPANAGIOTIS MOURMOURIS
PANAGIOTIS MOURMOURIS
IVIoannis Varkarakis
Ioannis Varkarakis

28 March 2025 in Future Internet
Verified
Journal Article
Open access
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GEORGIOS FERETZAKISGEORGIOS FERETZAKIS
GEORGIOS FERETZAKIS
EVEvangelia Vagena
Evangelia Vagena
KKKonstantinos Kalodanis
Konstantinos Kalodanis
PPParaskevi Peristera
Paraskevi Peristera
Dimitris KallesDimitris Kalles
Dimitris Kalles
AAAthanasios Anastasiou
Athanasios Anastasiou
Large Language Models (LLMs) have revolutionized natural language processing but present significant technical and legal challenges when confronted with the General Data Protection Regulation (GDPR). This paper examines the complexities involved in reconciling the design and operation of LLMs with GDPR requirements. In particular, we analyze how key GDPR provisions—including the Right to Erasure, Right of Access, Right to Rectification, and restrictions on Automated Decision-Making—are challenged by the opaque and distributed nature of LLMs. We discuss issues such as the transformation of personal data into non-interpretable model parameters, difficulties in ensuring transparency and accountability, and the risks of bias and data over-collection. Moreover, the paper explores potential technical solutions such as machine unlearning, explainable AI (XAI), differential privacy, and federated learning, alongside strategies for embedding privacy-by-design principles and automated compliance tools into LLM development. The analysis is further enriched by considering the implications of emerging regulations like the EU’s Artificial Intelligence Act. In addition, we propose a four-layer governance framework that addresses data governance, technical privacy enhancements, continuous compliance monitoring, and explainability and oversight, thereby offering a practical roadmap for GDPR alignment in LLM systems. Through this comprehensive examination, we aim to bridge the gap between the technical capabilities of LLMs and the stringent data protection standards mandated by GDPR, ultimately contributing to more responsible and ethical AI practices.

6 November 2024 in Antibiotics
Verified
Journal Article
Open access
PDF file
ASAikaterini Sakagianni
Aikaterini Sakagianni
CKChristina Koufopoulou
Christina Koufopoulou
PKPetros Koufopoulos
Petros Koufopoulos
SKSofia Kalantzi
Sofia Kalantzi
Nikolaos TheodorakisNikolaos Theodorakis
Nikolaos Theodorakis
GEORGIOS FERETZAKISGEORGIOS FERETZAKIS
GEORGIOS FERETZAKIS
Background/Objectives: The emergence of antimicrobial resistance (AMR) due to the misuse and overuse of antibiotics has become a critical threat to global public health. There is a dire need to forecast AMR to understand the underlying mechanisms of resistance for the development of effective interventions. This paper explores the capability of machine learning (ML) methods, particularly unsupervised learning methods, to enhance the understanding and prediction of AMR. It aims to determine the patterns from AMR gene data that are clinically relevant and, in public health, capable of informing strategies. Methods: We analyzed AMR gene data in the PanRes dataset by applying unsupervised learning techniques, namely K-means clustering and Principal Component Analysis (PCA). These techniques were applied to identify clusters based on gene length and distribution according to resistance class, offering insights into the resistance genes’ structural and functional properties. Data preprocessing, such as filtering and normalization, was conducted prior to applying machine learning methods to ensure consistency and accuracy. Our methodology included the preprocessing of data and reduction of dimensionality to ensure that our models were both accurate and interpretable. Results: The unsupervised learning models highlighted distinct clusters of AMR genes, with significant patterns in gene length, including their associated resistance classes. Further dimensionality reduction by PCA allows for clearer visualizations of relationships among gene groupings. These patterns provide novel insights into the potential mechanisms of resistance, particularly the role of gene length in different resistance pathways. Conclusions: This study demonstrates the potential of ML, specifically unsupervised approaches, to enhance the understanding of AMR. The identified patterns in resistance genes could support clinical decision-making and inform public health interventions. However, challenges remain, particularly in integrating genomic data and ensuring model interpretability. Further research is needed to advance ML applications in AMR prediction and management.