Gizem Yapar

Dr. Gizem Yapar

Medical Microbiology, Istanbul University, Istanbul, İstanbul, Turkey (Türkiye)

Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

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

Representative Publications

View All Publications
9 October 2023 in Pathogens
Verified
Journal Article
Open access
PDF file
Hayriye Kırkoyun UysalHayriye Kırkoyun Uysal
Hayriye Kırkoyun Uysal
MKMuammer Osman Köksal
Muammer Osman Köksal
Kutay SarsarKutay Sarsar
Kutay Sarsar
PSPinar Soguksu
Pinar Soguksu
GGGonca Erkose Genc
Gonca Erkose Genc
AAAli Agacfidan
Ali Agacfidan
Among sexually transmitted diseases, HIV causes very serious clinical manifestations that can lead to death. As a result, millions of people have to live with this problem that threatens their health. The virus attacks the immune system of the host, especially CD4+ T lymphocytes, causing the suppression of the immune system. CD4, CD8 counts, and HIV RNA viral loads are monitored in HIV-infected patients with antiretroviral treatment, and CD4 counts play an important role in determining the effectiveness of the treatment. Despite the advances in treatment in the present day, opportunistic infections are the main cause of morbidity and mortality in these patients, and the evaluation of immunological parameters is valuable for the prognosis of the disease in this process. In the present study, the purpose was to investigate the opportunistic infections faced by naive HIV-positive patients who applied to our laboratory and were diagnosed between 2019 and 2022 during their one-year treatment period, and the correlation of the immunological parameters was also evaluated retrospectively using the hospital automation system and laboratory data. A total of 107 opportunistic causative microorganisms were identified in 87 of the 230 HIV-positive patients over one year. T. pallidum was detected in 43 (18.6%) of these patients, Cytomegalovirus (CMV) in 32 (13.9%), Epstein–Barr virus (EBV) in 9 (3.9%), Hepatitis B virus (HBV) in 10 (4.3%), C. albicans in 7 (3%), M. tuberculosis in 3 (1.3%), Hepatitis C virus (HCV) in 2 (0.8%), and C. glabrata in 1 (0.4%) patient. Although mono-agent co-infections were determined in 69 of 87 people living with HIV, two-agent co-infections were detected in 16 HIV patients, and three-agent co-infections were identified in two HIV patients. Considering the correlation between the CD4/CD8 ratio and infection positivity, a moderate negative correlation was determined with HIV RNA viral load and CMV infection. The CD4/CD8 ratio had a low negative correlation with EBV and C. albicans infections. It was also found that the follow-up of HIV RNA load in the diagnosis of T. pallidum, CMV, EBV, and C. albicans may be meaningful. Opportunistic infections mainly affect immunosuppressed patients and can be prevented with effective treatment. Although it is already known that HIV patients may face different infections during their treatment, it was concluded that more attention should be paid to T. pallidum, CMV, EBV, and C. albicans agents. These infections should be routinely monitored with HIV viral load and the CD4/CD8 ratio.

29 May 2025 in Viruses
Verified
Journal Article
Open access
PDF file
MOMustafa Onel
Mustafa Onel
Hayriye Kırkoyun UysalHayriye Kırkoyun Uysal
Hayriye Kırkoyun Uysal
Arat HulikyanArat Hulikyan
Arat Hulikyan
YUYasemin Ayşe Uçar
Yasemin Ayşe Uçar
GYGizem Yapar
Gizem Yapar
AAAli Agacfidan
Ali Agacfidan
The aim of the study was to determine the prevalence rates of respiratory pathogens using syndromic tests and also to show which respiratory viruses were detected in suspected cases, especially during and after the pandemic period. A total of 1984 different respiratory tract samples from various departments were included and studied with the QIAstat-Dx device in 2021–2023. The samples were studied with the QIAstat-Dx1 Respiratory SARS-CoV-2 Panel. The kit used was a fully automated, multiplex syndromic test that detected SARS-CoV-2 and 21 other respiratory tract pathogens. As a result of the study, the prevalence of Rhinovirus/Enterovirus (RV/EV) (18.59%), RV/EV-SARS-CoV-2 (42.74%), SARS-CoV-2 (5.04%), and Influenza A Virus (IAV) (5.59%) agents was found to be higher than other agents during the period investigated. Among the 1984 patients examined, 959 (48.33%) had a single viral agent, 156 (7.86%) had double coinfection, 11 (0.55%) had triple coinfection and 1 patient had quadruple coinfection. Nearly half of the patients had a straightforward infection, which helps clinicians in directing specific treatment methods. The study results demonstrate that during the pandemic period, the detection of respiratory pathogens such as SARS-CoV-2 and RV/EV was not only critical for accurate diagnosis but also served as an important indicator of the broader epidemiological trends in respiratory infections. The seasonal distribution showed that while RV/EV was frequently present, its coinfection with SARS-CoV-2 was notably observed only in the first trimester. In light of our findings showing high rates of SARS-CoV-2 and RV/EV detection, along with diverse patterns of coinfection in clinical samples, such comprehensive testing not only assists in rapid diagnosis but also informs public health strategies by reflecting the evolving landscape of respiratory infections in the pandemic and post-pandemic era.

8 March 2024 in Viruses
Verified
Journal Article
Open access
PDF file
EOEvrim Ozdemir
Evrim Ozdemir
TSTugba Sarac Sivrikoz
Tugba Sarac Sivrikoz
Kutay SarsarKutay Sarsar
Kutay Sarsar
DTDilruba Tureli
Dilruba Tureli
MOMustafa Onel
Mustafa Onel
Hayriye Kırkoyun UysalHayriye Kırkoyun Uysal
Hayriye Kırkoyun Uysal
Cytomegalovirus (CMV) can cause serious complications in immunocompromised individuals and fetuses with congenital infections. These can include neurodevelopmental impairments and congenital abnormalities in newborns. This paper emphasizes the importance of concurrently evaluating ultrasonography findings and laboratory parameters in diagnosing congenital CMV infection. To examine the prenatal characteristics of CMV DNA-positive patients, we assessed serum and amniotic fluid from 141 pregnant women aged 19–45 years, each with fetal anomalies. ELISA and PCR tests, conducted in response to these amniocentesis findings, were performed at an average gestational age of 25 weeks. Serological tests revealed that all 141 women were CMV IgG-positive, and 2 (1.41%) had low-avidity CMV IgG, suggesting a recent infection. CMV DNA was detected in 17 (12.05%) amniotic fluid samples using quantitative PCR. Of these, 82% exhibited central nervous system abnormalities. Given that most infections in pregnant women are undetectable and indicators non-specific, diagnosing primary CMV in pregnant women using clinical findings alone is challenging. We contend that serological tests should not be the sole means of diagnosing congenital CMV infection during pregnancy.

4 February 2025 in Diagnostics
Verified
Journal Article
Open access
PDF file
GYGizem Yapar
Gizem Yapar
MKMuammer Osman Köksal
Muammer Osman Köksal
Kutay SarsarKutay Sarsar
Kutay Sarsar
PSpınar soğuksu
pınar soğuksu
Mehmet DemirciMehmet Demirci
Mehmet Demirci
Hayriye Kırkoyun UysalHayriye Kırkoyun Uysal
Hayriye Kırkoyun Uysal
Background/Objectives: T. pallidum subsp. pallidum is a spirochete that only causes disease in humans as the causative agent of syphilis. HIV and syphilis have common transmission routes. In the present study, our aim was to evaluate the presence of syphilis coinfection in people living with HIV using conventional and reverse algorithms and to investigate its effects on laboratory parameters. Methods: The traditional algorithm for syphilis begins testing with the non-treponemal test. If the non-treponemal test is reactive, a treponemal test is then used to confirm syphilis infection. The reverse algorithm for syphilis begins testing with the treponemal test. If this test is reactive, then a non-treponemal test is performed. When the non-treponemal test is non-reactive, a second treponemal test is performed. Results: A total of 200 patients were included in the study. While 22 patients were determined to be syphilis-positive using the traditional algorithm, 37 patients were determined to be syphilis-positive using the reverse algorithm. Most of the patients who had syphilis coinfection were homosexual. Conclusions: It was found that syphilis coinfection had no effects on CD4+ T-lymphocyte and CD8+ T-lymphocyte values, CD4/CD8 rates, and HIV RNA amounts. People living with HIV must be screened and followed up for syphilis and other sexually transmitted diseases at certain intervals.