Ondrej Zahornacky

Dr. Ondrej Zahornacky

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Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

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

Representative Publications

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4 March 2023 in Diagnostics
Verified
Journal Article
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OZOndrej Zahornacky
Ondrej Zahornacky
SPStefan Porubcin
Stefan Porubcin
ARAlena Rovňáková
Alena Rovňáková
PJPavol Jarčuška
Pavol Jarčuška
Multisystem inflammatory syndrome in adults (MIS-A) is an uncommon but severe and still understudied post-infectious complication of COVID-19. Clinically, the disease manifests itself most often 2–6 weeks after overcoming the infection. Young and middle-aged patients are especially affected. The clinical picture of the disease is very diverse. The dominant symptoms are mainly fever and myalgia, usually accompanied by various, especially extrapulmonary, manifestations. Cardiac damage (often in the form of cardiogenic shock) and significantly increased inflammatory parameters are often associated with MIS-A, while respiratory symptoms, including hypoxia, are less frequent. Due to the seriousness of the disease and the possibility of rapid progression, the basis of a successful treatment of the patient is early diagnosis, based mainly on anamnesis (overcoming the disease of COVID-19 in the recent past) and clinical symptoms, which often imitate other severe conditions such as, e.g., sepsis, septic shock, or toxic shock syndrome. Because of the danger of missing the treatment, it is necessary to initiate it immediately after the suspicion of MIS-A is expressed, without waiting for the results of microbiological and serological examinations. The cornerstone of pharmacological therapy is the administration of corticosteroids and intravenous immunoglobulins, to which the majority of patients clinically react. In this article, the authors describe the case report of a 21-year-old patient admitted to the Clinic of Infectology and Travel Medicine for febrility up to 40.5 °C, myalgia, arthralgia, headache, vomiting, and diarrhea three weeks after overcoming COVID-19. However, as part of the routine differential diagnosis of fevers (imaging and laboratory examinations), their cause was not clarified. Due to the overall worsening of the condition, the patient was transferred to the ICU with suspicion of developing MIS-A (he met all clinical and laboratory criteria). Given the above, reserve antibiotics, intravenous corticosteroids, and immunoglobulins were added to the treatment due to the risk of missing them, with a good clinical and laboratory effect. After stabilizing the condition and adjusting the laboratory parameters, the patient was transferred to a standard bed and sent home.

OZOndrej Zahornacky
Ondrej Zahornacky
SPStefan Porubcin
Stefan Porubcin
ARAlena Rovňáková
Alena Rovňáková
PJPavol Jarčuška
Pavol Jarčuška
Inanimate surfaces are often referred to as nosocomial bacterial reservoirs and represent an important vector in the process of spreading pathogens to patients. Most gram-negative rods can survive on inanimate surfaces for several months. The aim of this study is to determine the prevalence and resistance of gram-negative bacteria isolated from the inanimate surfaces of two selected hospital departments. MALDI-TOF identified gram-negative rods isolated from inanimate surfaces. Antibiotic resistance was determined using a disk diffusion method, and the phenotype of resistance was determined using an inhibitory analyzer. From the inanimate surfaces, 98 strains of gram-negative nosocomial bacteria were identified by the MALDI-TOF MS. The most frequently isolated bacterium occurring in both departments was Pseudomonas aeruginosa (n = 33), followed by Acinetobacter baumannii (n = 20) and Enterobacter cloacae (n = 14). The most common phenotypic type of resistance in both departments was ampicillin resistance—AmpC (n = 38), then production of extended-spectrum β-lactamase (ESBL) (n = 33), followed by SHV-1 (n = 11), TEM-1 (n = 11), and fluoroquinolone resistance—Qnr (n = 22). The nosocomial important enzymes capable of hydrolyzing carbapenems, OXA-48 and metallo-β-lactamases, were confirmed in 12 and 2 cases, respectively. The results of our study prove that inanimate surfaces in hospitals are a reservoir of resistant gram-negative bacteria, which directly threaten hospitalized patients.

20 May 2024 in Microorganisms
Verified
Journal Article
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OZOndrej Zahornacky
Ondrej Zahornacky
ARAlena Rovňáková
Alena Rovňáková
MSMaria Surimova
Maria Surimova
SPStefan Porubcin
Stefan Porubcin
PJPavol Jarčuška
Pavol Jarčuška
Introduction: The pandemic instigated by the SARS-CoV-2 virus has led to over 7 million deaths globally, primarily attributable to viral pneumonia. Identifying fundamental markers associated with an elevated risk of mortality can aid in the early identification of patients prone to disease progression to a severe state, enabling prompt intervention. Methods: This was a single-center, retrospective study. Results: In this study, we examined 299 patients admitted to the Department of Infectology and Travel Medicine in Košice, Slovakia, with PCR-confirmed COVID-19 pneumonia. Patients were monitored from 1 January 2021 to 31 March 2021, with the endpoint being discharge from the hospital or death. All patient-related data were retrospectively collected from medical records. This study identified several risk factors significantly associated with an increased risk of mortality, including the requirement of HFNO (p < 0.001), age over 60 years (p < 0.001), Ne/Ly values of >6 (p < 0.001), as well as certain lymphocyte subtypes—CD4+ < 0.2 × 109/L (p = 0.035), CD8+ < 0.2 × 109/L (p < 0.001), and CD19+ < 0.1 × 109/L (p < 0.001)—alongside selected biochemical inflammatory markers—IL-6 > 50 ng/L (p < 0.001) and lactate > 3 mmol/L (p < 0.001). Conclusions: We confirmed that the mentioned risk factors were significantly associated with the death of patients from viral pneumonia in the hospital.

26 May 2022 in Medicina
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Journal Article
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SPStefan Porubcin
Stefan Porubcin
ARAlena Rovňáková
Alena Rovňáková
OZOndrej Zahornacky
Ondrej Zahornacky
PJPavol Jarčuška
Pavol Jarčuška
Cerebrospinal fluid (CSF) leakage is a rare condition. Prompt diagnosis and early treatment of CSF leakage minimizes the risk of severe complications such as bacterial meningitis. Different diagnostic modalities are used to detect the site of CSF leakage but often with unreliable results. The literature offers limited evidence-based guidance on the diagnostic approach for rhinorrhea. Correct localization of the defect is the mainstay for successful surgical treatment. Herein, we describe a case of recurrent meningitis due to cranio-nasal fistula and rhinorrhea successfully localized with radioisotope cisternography (RIC). We provide a detailed and practical overview of the RIC procedure and compare different imaging modalities used to detect the site of CSF leakage.

27 September 2023 in Microbiology Research
Verified
Journal Article
Open access
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OZOndrej Zahornacky
Ondrej Zahornacky
SPStefan Porubcin
Stefan Porubcin
ARAlena Rovňáková
Alena Rovňáková
JFJan Fedacko
Jan Fedacko
PJPavol Jarčuška
Pavol Jarčuška
Leptospirosis is a zoonotic disease caused by bacteria from the genus Leptospira. The infection occurs mainly in developing countries in the tropical zone and countries with lower hygiene standards. The highest incidence is observed especially in environments associated with the presence of rodents, mainly rats, which are a potential source of infection. The clinical manifestations and severity of leptospirosis are highly variable. This case report describes the a 53-year-old patient (male) without comorbidities, who was admitted to an infectious disease department in the east of Slovakia for jaundice, general fatigue, weakness, and fever (health difficulties for approximately 7 days at home). The clinical laboratory picture of the patient was dominated by significant hyperbilirubinemia, acute renal failure, hepatopathy, severe thrombocytopenia, and involvement of the lung parenchyma in the sense of bilateral interstitial pneumonia on chest X-ray. A double combination of antibiotics (ceftriaxone and clarithromycin) were added to the treatment. During hospitalization, a diagnosis of leptospirosis was suspected based on medical history and the results of laboratory tests and was subsequently confirmed serologically. The antibiotic regimen was de-escalated to cephalosporin (ceftriaxone) monotherapy with adequate laboratory and clinical effects (on the 4th day). The patient was discharged after a total of 18 days in good clinical condition.

13 November 2025 in Antibiotics
Verified
Journal Article
Open access
PDF file
SPStefan Porubcin
Stefan Porubcin
ARAlena Rovňáková
Alena Rovňáková
OZOndrej Zahornacky
Ondrej Zahornacky
PJPavol Jarčuška
Pavol Jarčuška
Background: The COVID-19 pandemic profoundly affected healthcare delivery and antibiotic prescribing, raising concerns about increasing antimicrobial resistance. This study investigated seven-year trends in bacterial resistance, underlying resistance mechanisms, and antibiotic consumption in COVID-19 and non-COVID-19 units at a tertiary hospital in Slovakia. Methods: A retrospective cohort analysis (2018–2024) was conducted using clinical isolates of Klebsiella sp., Acinetobacter sp., and P. aeruginosa. Data on hospitalizations, resistance profiles, resistance mechanisms, and standardized antibiotic use were compared between COVID-19 and non-COVID-19 departments. Results: Hospitalizations markedly decreased in COVID-19 units, while pathogen occurrence—particularly of Acinetobacter sp.—was substantially higher compared with non-COVID-19 units. Resistance in Klebsiella sp. shifted from extended-spectrum beta-lactamase production to carbapenemase production. Acinetobacter sp. remained highly resistant, although some declines were observed in ceftazidime and gentamicin resistance. P. aeruginosa showed a gradual reduction in resistance, notably to piperacillin/tazobactam and imipenem. Antibiotic consumption was consistently higher in COVID-19 units, particularly for broad-spectrum beta-lactams and carbapenems, whereas fluoroquinolone use decreased over time. Clinically effective treatment options were considerably fewer in COVID-19 units, often limited to colistin. Conclusions: COVID-19 units experienced greater pathogen burden, higher broad-spectrum antibiotic exposure, and increased prevalence of critical resistance mechanisms. Tailored antimicrobial stewardship and infection prevention, and control are essential to reduce selective pressure and preserve last-line antibiotics.