Nikolaos Katzilakis

Dr. Nikolaos Katzilakis

orcid

Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

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

Representative Publications

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10 November 2020 in Journal of Fungi
Verified
Journal Article
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EVEleni Vasileiou
Eleni Vasileiou
APAnna Paisiou
Anna Paisiou
CTCharoula Tsipou
Charoula Tsipou
APAPOSTOLOS POURTSIDIS
APOSTOLOS POURTSIDIS
VGVasiliki Galani
Vasiliki Galani
ATHANASIOS TRAGIANNIDISATHANASIOS TRAGIANNIDIS
ATHANASIOS TRAGIANNIDIS
Candidemia is an important cause of morbidity and mortality especially in immunocompromised and hospitalized patients. We retrospectively collected data of candidemia cases that occurred in the seven Hematology-Oncology Departments/Units of Greece and the Stem Cell Transplant Unit between 2015 and 2019. In total, 19 episodes of candidemia in 19 patients were recorded. The majority of the patients (78.9%) had at least one risk factor for candidemia. The most frequent risk factors associated with candidemia observed in our patients were prolonged duration of hospitalization (30 days, range 1–141), presence of a central venous catheter at diagnosis of candidemia (73.7%) and antibiotics use during the last two weeks (84.2%). Candida parapsilosis was the most common species isolated accounting for 42.1%, followed by C. albicans (26.3%) and C. famata (15.8%). Nearly all of the patients (84.2%) received antifungal monotherapy with liposomal amphotericin B or echinocandins. The central venous catheter was removed in 78.6% of patients and the median time between the first positive blood culture and catheter removal was 3 days (range 1–9). Mortality at 28 days was 26.3%. In conclusion, a predominance of non-albicans species was observed in our study in conformity with the global trend.

1 January 2018 in Journal of Pediatric Hematology/Oncology
Verified
Journal Article
Closed access
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Zoi Dorothea PanaZoi Dorothea Pana
Zoi Dorothea Pana
MKMaria Kourti
Maria Kourti
KVKaterina Vikelouda
Katerina Vikelouda
AVAntonia Vlahou
Antonia Vlahou
NKNikolaos Katzilakis
Nikolaos Katzilakis
Emmanuel RoilidesEmmanuel Roilides
Emmanuel Roilides
Antifungal prophylaxis (AFP) is recommended in at-risk hematology-oncology patients. We evaluated the safety of AFP with voriconazole (VRC) in pediatric hematology/oncology patients. A retrospective study of VRC AFP in children with malignancies hospitalized in all 7 Greek pediatric hematology/oncology centers during 2008 to 2012 was conducted. Patients’ demographics, outcome, and adverse event (AE) data were recorded. Four hundred twenty-nine VRC AFP courses in 249 patients (median age 6 y, 55% boys) were studied. The most common underlying diseases were acute lymphoblastic leukemia (51%), non Hodgkin lymphoma (8.6%), and acute myeloid leukemia (7.7%). The median number of VRC courses per patient was 1.7, whereas the median VRC dose was 7 mg/kg (range, 5 to 7 mg/kg) every 12 hours. During the last 2 weeks before AFP, 51% of the patients had received corticosteroids, 43% suffered from severe neutropenia, and 17.3% from mucositis. The median duration of VRC AFP was 17 days (range, 1 to 31 d). A single breakthrough fungemia due to Candida glabrata was recorded. Only 1 patient died due to the underlying disease. The most common AEs reported in 70/429 (16.3%) courses with ≥1 AE were elevated liver enzymes (50%), hypokalemia (24.3%), and ophthalmological disorders (14.3%). The median time of AE onset was 5 days (range, 1 to 21 d). Among 70 AEs reported, 38.5%, 48.4%, and 12.8% were of grade I, II, and III, respectively. VRC prophylaxis in pediatric hematology/oncology patients appears to be well tolerated.

1 January 2008 in Pediatric Hematology and Oncology
Verified
Journal Article
Closed access
EMElpis Mantadakis
Elpis Mantadakis
MRMaria Raissaki
Maria Raissaki
MTMaria Tzardi
Maria Tzardi
NKNikolaos Katzilakis
Nikolaos Katzilakis
ACAthanasios Chatzimichael
Athanasios Chatzimichael
MKMaria Kalmanti
Maria Kalmanti
Primary hepatic lymphomas are exceedingly rare in children, with less than a dozen cases described to date. The authors present an 8.5-year-old boy with Burkitt lymphoma of the liver who had isolated multifocal liver lesions that exhibited a multilayered progressive enhancing pattern on MRI. Diagnosis was achieved after laparotomy and incisional biopsy that failed to detect disease outside the liver. The patient received short, intensive multiagent chemotherapy. He is currently well 22 months after the end of chemotherapy. This case illustrates that clinical judgment in conjunction with unusual imaging findings may contribute to the diagnosis of common tumors in rare locations.

18 July 2024 in Journal of Fungi
Verified
Journal Article
Open access
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EMEleni Moraitaki
Eleni Moraitaki
Ioannis KyriakidisIoannis Kyriakidis
Ioannis Kyriakidis
IPIordanis Pelagiadis
Iordanis Pelagiadis
NKNikolaos Katzilakis
Nikolaos Katzilakis
MSMaria Stratigaki
Maria Stratigaki
ESEftichia Stiakaki
Eftichia Stiakaki
Although advances in the management of pediatric neoplasms have profoundly improved infectious disease outcomes, invasive fungal diseases (IFDs) remain a major cause of morbidity and mortality in children and adolescents with high-risk hematological malignancies. A retrospective study was conducted in the Pediatric Hematology–Oncology Department of the University General Hospital of Heraklion for 2013–2022 to estimate the prevalence and describe the clinical and epidemiological characteristics of IFDs for pediatric and adolescent patients with neoplasia. Demographic, clinical, and laboratory parameters were analyzed to identify risk factors for the development of IFD. The overall prevalence of IFDs was estimated to be 7.8% (12/154 patients) throughout the study. The mean age at IFD diagnosis was 9.8 years (SD 6.4 years). The most common IFD was possible/probable invasive pulmonary aspergillosis (IPA; in ≈50%), followed by candidemia/invasive candidiasis (in 44%). Candida parapsilosis was the most prevalent Candida species (4/6 events). Of interest, the majority (75%) of IFDs were breakthrough infections. Patients with increased risk for IFDs were those who were colonized by fungi in sites other than the oral cavity, hospitalized in the intensive care unit for >7 days, received >7 different antimicrobials in the last 3 months, or had severe neutropenia for >44 days. Two children out of a total of 12 with IFD died due to refractory disease or relapse (16.7%). More detailed and prospective epidemiological studies on fungal infections in pediatric patients with hematological or solid neoplasms can contribute to the optimization of prevention and treatment.

15 November 2023 in Children
Verified
Journal Article
Open access
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IPIordanis Pelagiadis
Iordanis Pelagiadis
Ioannis KyriakidisIoannis Kyriakidis
Ioannis Kyriakidis
NKNikolaos Katzilakis
Nikolaos Katzilakis
CKChrysoula Kosmeri
Chrysoula Kosmeri
DVDanai Veltra
Danai Veltra
ESEftichia Stiakaki
Eftichia Stiakaki
Diamond–Blackfan anemia (DBA) is a ribosomopathy characterized by bone marrow erythroid hypoplasia, which typically presents with severe anemia within the first months of life. DBA is typically attributed to a heterozygous mutation in a ribosomal protein (RP) gene along with a defect in the ribosomal RNA (rRNA) maturation or levels. Besides classic DBA, DBA-like disease has been described with variations in 16 genes (primarily in GATA1, followed by ADA2 alias CECR1, HEATR3, and TSR2). To date, more than a thousand variants have been reported in RP genes. Splice variants represent 6% of identifiable genetic defects in DBA, while their prevalence is 14.3% when focusing on pathogenic and likely pathogenic (P/LP) variants, thus highlighting the impact of such alterations in RP translation and, subsequently, in ribosome levels. We hereby present two cases with novel pathogenic splice variants in RPS17 and RPS26. Associations of DBA-related variants with specific phenotypic features and malignancies and the molecular consequences of pathogenic variations for each DBA-related gene are discussed. The determinants of the spontaneous remission, cancer development, variable expression of the same variants between families, and selectivity of RP defects towards the erythroid lineage remain to be elucidated.

1 May 2021 in Journal of Fungi
Verified
Journal Article
Open access
PDF file
AMAnthi Marina Markantonatou
Anthi Marina Markantonatou
ATHANASIOS TRAGIANNIDISATHANASIOS TRAGIANNIDIS
ATHANASIOS TRAGIANNIDIS
VGVasiliki Galani
Vasiliki Galani
DDDimitrios Doganis
Dimitrios Doganis
KAKondylia Antoniadi
Kondylia Antoniadi
Timoleon-Achilleas VyzantiadisTimoleon-Achilleas Vyzantiadis
Timoleon-Achilleas Vyzantiadis
An audit based on a specific questionnaire was attempted, in order to investigate the mycology laboratory diagnostic capacity for invasive fungal diseases (IFDs) in Greek Paediatric Haematology-Oncology departments/units. The study provided the relevant information for the years 2019 and 2020 and included data from all units, concerning culture-based methods and direct microscopy, phenotypic and molecular identification, sensitivity testing, serology and molecular diagnosis, as well as therapeutic drug monitoring. The target was mostly to reveal the level of laboratory coverage for hospitalised paediatric patients, independently of the possibility of performing the tests in the host hospital, or otherwise to refer the specimens elsewhere. In total, the current study demonstrated that the most important facilities and services regarding the IFD diagnostics for paediatric haematology-oncology patients in Greece are available and relatively easily accessible, with a reasonable turnaround time. Acting as an initial registry for further improvements, the audit can serve as a valuable approach to the actual situation and future perspectives. A national clinical mycology network under the auspices of the relevant scientific societies will probably facilitate collaboration between all the departments (clinical and laboratory) involved in invasive fungal infections and provide an easier approach to any necessary test for any hospitalised patient.