Konstantinos Alexiou

Dr. Konstantinos Alexiou


Research Focus & Metrics

Academic Career Length

18Years (2009-Present)

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

Representative Publications

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31 January 2020 in Antibiotics
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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.

1 September 2017 in Annals of Medicine & Surgery
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Journal Article
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KAKonstantinos Alexiou
Konstantinos Alexiou
IDIoannis Drikos
Ioannis Drikos
MTMaria Terzopoulou
Maria Terzopoulou
NSNikolaos Sikalias
Nikolaos Sikalias
AIArgyrios Ioannidis
Argyrios Ioannidis
NENikolaos Economou
Nikolaos Economou
Every surgical wound is colonized by bacteria, but only a small percentage displays symptoms of infection. The distribution of pathogens isolated in surgical site infections has not significantly changed over the last decades. Staph. Aureus, Coag(-) Staphylococci, Enterococcus spp and E. Coli are the main strains appearing. In addition, a continuously rising proportion of surgical site infections caused by resistant bacterial species (MRSA, C. Albicans) has been reported. This prospective and randomized clinical study was performed in the 1st Surgical Clinic of Sismanoglion General Hospital of Athens, from February 2009 to February 2015. Patients undergoing elective surgery in the upper or lower digestive system were randomized to receive antimicrobial treatment as chemoprophylaxis. Each patient filled a special monitoring form, recording epidemiological data, surgery related information, surgical site infections (deep and superficial), as well as postoperative morbidity (urinary and respiratory infections included). The monitoring of patients was carried by multiple visits on a daily basis during their hospitalization and continued after they were discharged via phone to postoperative day 30. Our overall SSI incidence was 4,3% (31patients out of a whole of 715 patients). Specifically, the incidence of SSIs for scheduled surgery of the upper GI tract was 2,2% (11 out of 500 patients) and for the lower GI tract was 9,3% (20 out of 215 patients). Seven main pathogens were isolated from patients with SSIs: Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Pseudomonas aeruginosa, Bacteroides fragilis, Staphylococcus aureus and Enterococcus faecalis. Their growth rates were respectively: S. Aureus (17,3%), E. faecalis (19,5%), P. aeruginosa (10,5%), B. Fragilis (13,4%) E. coli (20,4%), Enterobacter cloacae (9,1%) and K. Pneumoniae (9,8%). In addition, all the SSIs were found to be multimicrobial. Several studies have already revealed that patient characteristics and coexisting morbidities such as obesity, smoking, heart or renal failure, pre-existing localized infections and patients' age (especially if age exceeds 65) seem to be independent prognostic factors for surgical field infections. Additionally, classification of the surgical wound, surgical operation complexity, preoperative hospitalization, prolongation of surgical time and need for transfusions have been proved to differentiate the incidence of SSIs. In conclusion, surgical site infections are important complications affecting the healthcare services, the cost of hospitalization and the patient himself. Future thorough studies are expected to reveal much more data, regarding predisposing and precautionary patient and hospital characteristics.

11 July 2015 in Journal of Medical Case Reports
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KAKonstantinos Alexiou
Konstantinos Alexiou
AIArgyrios Ioannidis
Argyrios Ioannidis
IDIoannis Drikos
Ioannis Drikos
NSNIKOLAOS SIKALIAS
NIKOLAOS SIKALIAS
NENicolaos Economou
Nicolaos Economou
Torsion of the omentum is a benign self-limiting disorder, which is difficult to diagnose because the main symptoms are similar to those of other abdominal diseases. Most of the published cases had been diagnosed during operation via direct eye view. According to several studies, it is important that the correct preoperative diagnosis is made as omental torsion can be treated conservatively in most cases without any complications avoiding surgical intervention. However, patients should be under clinical and laboratory observation in order to detect symptoms that would lead to surgical intervention in which case a laparoscopy is the appropriate surgical treatment. Torsion of the great omentum is a rare cause of acute abdominal pain which is usually misdiagnosed. In this study we report two cases, a 52-year-old Greek woman and a 68-year-old Greek man, who presented at our emergency room with symptoms such as right lower quadrant pain and tenderness similar to acute appendicitis. In both cases a surgical exploratory laparotomy of the abdomen revealed a twisted heavily congested segment of the right part of the greater omentum accompanied by intra-abdominal serosanguinous fluid. Greater omental torsion is difficult to diagnose preoperatively. It presents as acute abdominal pain located more often in the right iliac fossa. It is very important to make a correct preoperative diagnosis because omental torsion is a benign self-limiting disorder that can be treated conservatively, avoiding laparotomy. When a patient’s clinical, laboratory and radiological findings worsen or diagnosis is doubtful then laparoscopy is the appropriate method for diagnosis and treatment.

3 February 2009 in Cases Journal
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KAKonstantinos Alexiou
Konstantinos Alexiou
TSTIMOTHY SAKELLARIDIS
TIMOTHY SAKELLARIDIS
NSNikolaos Sikalias
Nikolaos Sikalias
IKIoannis Karanikas
Ioannis Karanikas
NENikolaos Economou
Nikolaos Economou
GAGiorgios Antsaklis
Giorgios Antsaklis
Background: The presence of subcutaneous emphysema, pneumomediastinum and pneumoperitoneum simultaneously is a rare complication of upper gastrointestinal endoscopy that usually indicates free perforation to the peritoneal cavity or the retroperitoneal space.Case presentation: We report an unusual case of a self-limited subcutaneous emphysema, pneumomediastinum and pneumoperitoneum following an unsuccessful ERCP for removal of a common bile duct stone.Conclusion: There was no radiological evidence of peritoneal or retroperitoneal perforation. This complication is distinct from pneumomediastinum and pneumoperitoneum due to perforation, and must be recognized, because it is benign and needs no surgical or radiological intervention.

10 December 2009 in Cases Journal
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NSNIKOLAOS SIKALIAS
NIKOLAOS SIKALIAS
KAKonstantinos Alexiou
Konstantinos Alexiou
LMLamprini Mountzalia
Lamprini Mountzalia
VTVasileios Triantafyllis
Vasileios Triantafyllis
GEGeorgios Efstathiou
Georgios Efstathiou
GAGeorgios Antsaklis
Georgios Antsaklis
Tuberculous colitis is a rare form of tuberculosis and is found in immunosuppressed patients, usually with the clinical appearance of Crohn's disease. The purpose of this article is to report a rare case of tuberculous colitis in a transplant patient, presenting in the form of bowel obstruction and acute abdomen. Case presentation A male patient, 51 years old, with a history of kidney transplant in a foreign country 19 months before, presented at the emergency department, after being referred by a primary care center, with obstipation during the previous week and acute abdominal pain. The patient had the clinical appearance of acute abdomen. Five days before the patient underwent colonoscopy, which revealed an intraluminal mass that partially occluded the lumen of the ascending colon. Blood tests revealed a mildly elevated WBC count and anaemia. Imaging studies revealed air in the peritoneal cavity and free fluid in the pelvis. The patient was diagnosed with perforation of a hollow viscus and was admitted for surgery During laparotomy the findings were a perforation of the cecum, a fragile mass (pseudopolyp), which occluded the lumen approximately in the middle of the ascending colon, diffuse erosions of the mucosa and pseudomembranes. A bezoar was found impacted at the level of the occlusion. There was also marked lymph node enlargement in the mesentery and ischaemia of the cecum. A typical right hemicolectomy was performed and special care was taken so, as not to damage the renal transplant. The pathological and microbiological (from free peritoneal fluid) investigation suggested the diagnosis of tuberculous colitis. Further blood tests and respiratory investigation confirmed the diagnosis of active tuberculosis, with the colon as a primary site. The patient received the appropriate antituberculous treatment. Tuberculous colitis is a rare form of tuberculosis and is found in immunosuppressed patients. Deferential diagnosis from other forms of colitis is usually problematic. Tuberculous colitis rarely manifests itself in the form of acute surgical abdomen. The possible diagnosis of tuberculous colitis must be always in mind when treating transplant patients.

25 June 2014 in Journal of Medical Case Reports
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KAKonstantinos Alexiou
Konstantinos Alexiou
AIArgyrios Ioannidis
Argyrios Ioannidis
IDIoannis Drikos
Ioannis Drikos
AFAthanasios Fotopoulos
Athanasios Fotopoulos
IKIoannis Karanikas
Ioannis Karanikas
NENikolaos Economou
Nikolaos Economou
Lesions of the ampulla of Vater are rare histological entities with an incidence of between 0.1 and 0.2% of gastrointestinal tumors. Until recently the main response to this kind of lesion was duodenopancreatectomy, regardless of the cellular atypia and local edema. In this study, we propose the application of transduodenal local excision of the ampulla of Vater especially in recognized cases of nonmalignant adenomas.