and Tatiana Tcherveniakova

Dr. and Tatiana Tcherveniakova


Research Focus & Metrics

Academic Career Length

3Years (2024-Present)

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

Representative Publications

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16 February 2025 in Viruses
Verified
Journal Article
Open access
PDF file
NKNeli Korsun
Neli Korsun
ITIvelina Trifonova Trifonova
Ivelina Trifonova Trifonova
DPDiana Pavlova
Diana Pavlova
YUYordanka Uzunova
Yordanka Uzunova
IIIvan Rosenov Ivanov
Ivan Rosenov Ivanov
ICIva Christova
Iva Christova
Influenza poses a serious threat to both individual and public health. This study aimed to investigate the virological and epidemiological characteristics of influenza infections and to explore the genetic diversity of the circulating influenza viruses. In total, 1886 nasopharyngeal specimens from patients with acute respiratory illnesses were tested against 13 respiratory viruses using a multiplex real-time PCR. Whole-genome sequencing, phylogenetic, and amino acid analyses of representative influenza strains were performed. At least one respiratory virus was detected in 869 (46.1%) patients; 87 (4.6%) were co-infected with two or three viruses. Influenza A(H1N1)pdm09 was the most prevalent virus (16.1%), followed by rhinoviruses (8.1%) and RSV (6.7%). Hemagglutinin (HA) genes of the 74 influenza A(H1N1)pdm09 viruses were categorized in subclades C.1.8, C.1.9, and C.1 within clade 5a.2a and D1, D.2, and D.3 within clade 5a.2a.1. The A(H3N2) viruses analyzed belonged to clade 2a.3a.1, subclades J.2 and J.1. The sequenced B/Victoria lineage viruses fell into clade V1A.3a.2, subclades C.5.6 and C.5.7. Amino acid substitutions in most viral proteins were identified compared with the vaccine strains, including in the HA antigenic sites. This study demonstrated the dominant distribution of the influenza A(H1N1)pdm09 virus among the respiratory viruses studied and the genetic diversity of the circulating influenza viruses.

27 September 2024 in Biomedicines
Verified
Journal Article
Open access
PDF file
ITIvelina Trifonova Trifonova
Ivelina Trifonova Trifonova
IMIveta Madzharova
Iveta Madzharova
NKNeli Korsun
Neli Korsun
VLViktoriya Stefanova Levterova
Viktoriya Stefanova Levterova
PVPetar Velikov
Petar Velikov
ICIva Christova
Iva Christova
Background: Mixed infections can worsen disease symptoms. This study investigated the impact of mixed infections with viral and bacterial pathogens in patients positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods: Using the in-house multiplex PCR method, we tested 337 SARS-CoV-2 positive samples for co-infections with three bacterial and 14 other viral pathogens. Results: Between August 2021 and May 2022, 8% of 337 SARS-CoV-2-positive patients had bacterial co-infections, 5.6% had viral co-infections, and 1.4% had triple mixed infections. The most common causes of mixed infections were Haemophilus influenzae (5.93%) and respiratory syncytial virus (RSV) (1.18%). Children < 5 years old had more frequent co-infections than adults < 65 years old (20.8% vs. 16.4%), while adults showed a more severe clinical picture with a higher C-reactive protein (CRP) level (78.1 vs.16.2 mg/L; p = 0.033), a lower oxygen saturation (SpO2) (89.5 vs. 93.2%), and a longer hospital stay (8.1 vs. 3.1 days; p = 0.025) (mean levels). The risk of a fatal outcome was 41% in unvaccinated patients (p = 0.713), which increased by 2.66% with co-infection with two pathogens (p = 0.342) and by 26% with three pathogens (p = 0.005). Additionally, 50% of intensive care unit (ICU) patients had a triple infection, compared with only 1.3% in the inpatient unit (p = 0.0029). The risk of death and/or ICU admission was 12 times higher (p = 0.042) with an additional pathogen and increased by 95% (p = 0.003) with a third concomitant pathogen. Conclusions: Regular multiplex testing is important for prompt treatment and targeted antibiotic use.

25 November 2024 in Biomedicines
Verified
Journal Article
Open access
PDF file
RYRalitsa Yordanova
Ralitsa Yordanova
DSDimitar Strashimirov
Dimitar Strashimirov
RGRusina Stanislavova Grozdeva
Rusina Stanislavova Grozdeva
DIDaniel Ivanov
Daniel Ivanov
ITIvelina Trifonova Trifonova
Ivelina Trifonova Trifonova
ATand Tatiana Tcherveniakova
and Tatiana Tcherveniakova
Background: SARS-CoV-2 can trigger hyperinflammation, leading to severe COVID-19, presenting with pneumonia, acute respiratory distress syndrome (ARDS), and multiple organ failure. Specific biomarkers like leukocytes, CRP, NLR, AST, LDH, D-dimer, ferritin, and IL-6 are associated with disease severity. Anakinra, an IL-1 receptor antagonist, has been proposed to mitigate hyperinflammation, but its clinical efficacy remains uncertain. This study aimed to evaluate the effect of Anakinra on inflammatory biomarkers, oxygenation status, and survival outcomes in hospitalized patients with moderate to severe COVID-19 (according to the National Institute of Health severity scale), compared to standard treatment. Methods: A retrospective analysis included 65 patients (mean age 75.51 ± 9.54 years; 58.5% male, 41.5% female) hospitalized with moderate to severe COVID-19. Patients were divided into two groups: a control group receiving standard treatment (n = 24) and a target group treated with Anakinra (n = 41). Biomarkers and oxygenation status were assessed on Days 0, 3, and 7. Statistical analyses compared the groups for changes in leukocytes, NLR, CRP, AST, LDH, D-dimer, ferritin, and IL-6. Results: Anakinra treatment was associated with significant reductions in leukocytes, NLR, D-dimer, ferritin, IL-6, and CRP by Days 3 and 7. Improvements in oxygenation status were observed, although no survival benefits were noted. The control group showed no significant biomarker changes except for AST and LDH on Day 7. Conclusions: Anakinra demonstrated favorable effects on biomarkers and oxygenation in moderate to severe COVID-19 but did not improve survival. Further studies are needed to validate these findings.

11 September 2024 in Preprints.org
Verified
Preprint
Open access
PDF file
RYRalitsa Yordanova
Ralitsa Yordanova
DSDimitar Strashimirov
Dimitar Strashimirov
RGRusina Stanislavova Grozdeva
Rusina Stanislavova Grozdeva
DIDaniel Ivanov
Daniel Ivanov
ITIvelina Trifonova Trifonova
Ivelina Trifonova Trifonova
ATand Tatiana Tcherveniakova
and Tatiana Tcherveniakova
A prospective clinical-epidemiological study was conducted to evaluate the dynamics of biomarkers in hospitalized patients with moderate to severe COVID-19 (according to the National Institute of Health severity scale) treated with Anakinra, compared to those receiving standard treatment. The study included 65 patients with a mean age of 75.51±9.54 years, ranging from 44 to 99 years. Among the study participants, 38 (58.5%) were male and 27 (41.5%) were female. The patients were divided into two groups: control group (standard treatment): 24 patients (36.9%) and target group (Anakinra treatment): 41 patients (63.1%). The results showed a significant relationship between the dynamics of leukocytes, ASAT, LDH, D-dimer, ferritin, and IL-6 and the administration of Anakinra. In the control group, no significant dynamics were observed in leukocyte count, D-dimer, ferritin, or IL-6. A statistically significant decrease in ASAT and LDH values in the control group was noted only on Day 7. In the Anakinra group, significantly (or with borderline statistical significance, p<0.1) lower mean values were observed for leukocytes, NLR, D-dimer, ferritin, and IL-6 on Days 3 and 7 compared to the control group. Additionally, significantly lower CRP values were detected in the Anakinra group on Day 7 compared to the control group.

27 January 2025 in Preprints.org
Verified
Preprint
Open access
PDF file
NKNeli Korsun
Neli Korsun
ITIvelina Trifonova Trifonova
Ivelina Trifonova Trifonova
DPDiana T. Pavlova
Diana T. Pavlova
YUYordanka Uzunova
Yordanka Uzunova
IIIvan Rosenov Ivanov
Ivan Rosenov Ivanov
ICIva Christova
Iva Christova
Influenza poses a serious threat to both individual and public health . This study aimed to investigate the virological and epidemiological characteristics of influenza infections and to explore the genetic diversity of the circulating influenza viruses. In total, 1886 nasopharyngeal specimens from patients with acute respiratory illnesses were tested against 13 respiratory viruses using a multiplex real-time PCR. Whole-genome sequencing, phylogenetic, and amino acid analyses of representative influenza strains were performed. At least one respiratory virus was detected in 869 (46.1%) patients, 87 (4.6%) were co-infected with two or three viruses. Influenza A(H1N1)pdm09 was the most prevalent virus (16.1%), followed by rhinoviruses (8.1%) and RSV (6.7%). Hemagglutinin (HA) genes of the 74 influenza A(H1N1)pdm09 viruses were categorized in subclades C.1.8, C.1.9, and C.1 within clade 5a.2a and D1, D.2, and D.3 within clade 5a.2a.1 The A(H3N2) viruses analyzed belonged to clade 2a.3a.1, subclades J.2 and J.1. The sequenced B/Victoria lineage viruses fell into clade V1A.3a.2, subclades C.5.6 and C.5.7. Amino acid substitutions in most viral proteins were identified compared with the vaccine strains, including in the HA antigenic sites. This study demonstrated the dominant distribution of the influenza A(H1N1)pdm09 virus among the respiratory viruses studied and the genetic diversity of the circulating influenza viruses.

28 August 2024 in Preprints.org
Verified
Preprint
Open access
PDF file
IMIveta Madzharova
Iveta Madzharova
ITIvelina Trifonova Trifonova
Ivelina Trifonova Trifonova
NKNeli Korsun
Neli Korsun
VLViktoriya Stefanova Levterova
Viktoriya Stefanova Levterova
PVPetar Velikov
Petar Velikov
ICIva Christova
Iva Christova
The risk of a fatal outcome was 41% in unvaccinated patients (p = 0.713), which increased by 2.66% with co-infection with two pathogens (p = 0.342) and by 26% with three pathogens (p = 0.005). Additionally, 50% of ICU patients had a triple infection, compared with only 1.3% in the inpatient unit (p = 0.0029). The risk of death and/or ICU admission was 12 times higher (p = 0.042) with an additional pathogen and increased by 95% (p = 0.003) with a third concomitant pathogen. Regular multiplex testing is important for prompt treatment and targeted antibiotic use.