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    The Relationship Between COVID-19 Severity and Bacillus Calmette-Guerin (BCG)/ Mycobacterium Tuberculosis Exposure History in Healthcare Workers: A Multi-Center Study
    (2021) Torun, Serife; Ozkaya, Sevket; Sen, Nazan; Kanat, Fikret; Karaman, Irem; Yosunkaya, Sebnem; Sengoren Dikis, Ozlem; Asan, Ali; Aydogan Eroglu, Selma; Semih Atal, Sefa; Ayten, Omer; Aksel, Nimet; Ermis, Hilal; Ozcelik, Neslihan; Demirelli, Meryem; Kara, Iskender; Sumer, Sua; Marakoglu, Kamile; Uzer, Fatih; Uyar, Yasin; Cicek, Tuba; Unsal, Zuhal E.; Vatansev, Husamettin; Botan Yildirim, Berna; Kuruoglu, Tuba; Atilla, Aynur; Ersoy, Yasemin; Kandemir, Bahar; Durduran, Yasemin; Goksin Cihan, Fatma; Demirbas, Nur; Yildirim, Fatma; Tatar, Dursun; Akcay, M. Sule; 0000-0002-6530-6153; 0000-0002-8697-4919; 34014806; ABF-1652-2021
    The COVID-19 pandemic has brought countries' health services into sharp focus. It was drawn to our group's attention that healthcare workers (HCWs) had a lower mortality rate against higher COVID-19 incidence compared to the general population in Turkey. Since risk of exposure to tuberculosis bacillus among healthcare workers are higher than the population, we aimed to investigate if there is a relationship between BCG and Mycobacterium tuberculosis exposure history with COVID-19 severity in infected HCWs. This study was conducted with 465 infected HCWs from thirty-three hospitals to assess the relationship between COVID-19 severity (according to their hospitalization status and the presence of radiological pneumonia) and BCG and Mycobacterium tuberculosis exposure history. HCWs who required hospital admission had significantly higher rates of chronic diseases, radiological pneumonia, and longer working hours in the clinics. Higher rates of history of contact and care to tuberculosis patients, history of tuberculosis, and BCG vaccine were observed in hospitalized HCWs. HCWs who had radiological pneumonia had a significantly increased ratio of history of care to tuberculosis patients and a higher family history of tuberculosis. The findings from our study suggest that the lower mortality rate despite the more severe disease course seen in infected HCWs might be due to frequent exposure to tuberculosis bacillus and the mortality-reducing effects of the BCG vaccine.
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    Molecular Characterization of Drug Resistance in Hepatitis B Viruses Isolated from Patients with Chronical Infection in Turkey
    (2018) Aydin, Mehtap; Asan, Ali; Sayan, Murat; Akhan, Sila; Koruk, Suda Tekin; Aygen, Bilgehan; Sirmatel, Fatma; Eraksoy, Haluk; Tuna, Nazan; Kose, Sukran; Kaya, Ali; Tulek, Necla Eren; Demir, Nazlim Aktug; Mistik, Resit; Ormen, Bahar; Korkmaz, Fatime; Yildirmak, Taner; Ural, Onur; Turgut, Huseyin; Gunal, Ozgur; Demirtuk, Nese
    Background: Hepatitis B virus (HBV) has a high mutation rate due to its unusual replication strategy leading to the production of a large number of virions with single and double mutations. The mutations, in turn, are associated with the development of drug resistance to nucleos(t)ide analogs (NUCs) in patients before and during NUCs therapy. Objectives: The current study aimed at investigating the molecular characterization of HBV in Turkish patients with chronic hepatitis B (CHB) infection. Methods: Polymerase chain reaction (PCR) amplification and direct sequencing procedures were used to analyze mutations. The detected drug resistance mutations were divided into the nucleos(t) ide analogs primary, partial, and compensatory resistance groups. The amino acid substitutions of hepatitis B surface antigen (HBsAg) were categorized into antiviral drug - associated potential vaccine-escape mutations (ADAPVEMs) and typical HBsAg amino acid substitutions, which included hepatitis B hyperimmunoglobulin (HBIg) - selected escape mutation, vaccine escape mutation, hepatitis B misdiagnosis, and immune - selected amino acid substitutions. Results: The number of patients included in the study was 528 out of which 271 (51.3%) were treatment - naive and 351 (66.3%) were hepatitis B e antigen (HBeAg) - negative. Moreover, 325 (61.6%) were males with a mean age of 38 years (range: 18 - 69). Primary, partial, and compensatory resistance to NUCs was reported in 174 (32.9%) patients. Six different ADAPVEM motifs were determined in both treatment - naive and treatment - experienced patients, namely, sF161L/rtI169X, sE164D/rtV173L, sL172L/rtA181T, sL173F/rtA181V, sS195M/rtM204V, and sS196L/rtM204I. The prevalence of ADAPVEMs and typical HBsAg escape mutations was 5.3% (n = 28) and 34.8% (n = 184), respectively. Conclusions: The analysis of drug resistance should constitute a fundamental part of the follow - up period of patients with CHB undergone treatment with NUCs. The surveillance of development of drug resistance mutations, while receiving treatment for hepatitis B is of paramount importance to monitor and control the emerging resistance.