PROBLEMS of Infectious and Parasitic Diseases 2022-12-14T13:09:07+00:00 Assoc. Prof. Dimitur Shalamanov Open Journal Systems <p><strong>"PROBLEMS of Infectious and Parasitic Diseases"</strong> <span id="result_box" class="" lang="en">is <span class="">a <a href="" target="_blank" rel="noopener">peer-reviewed</a> open-access medical journal of scientific papers covering laboratory research data on human infectious diseases as well as its application for elucidation and management of epidemic processes. It is published by</span></span><span id="result_box" class="" lang="en"> <a href="" target="_blank" rel="noopener">National Centre of Infectious and Parasitic Diseases</a> in English, </span>with periodicity of three issues annually, in a print and digital version.</p> <p style="text-align: justify;"><strong><span class="" lang="en"><span class="">ISSN: 0204-9155 (Print)</span></span></strong></p> <p style="text-align: justify;"><strong><span class="" lang="en"><span class="">ISSN: 2815-2808 (Online)</span></span></strong></p> DETERMINATION OF INTRACELLULAR REACTIVE OXYGEN SPECIES IN T-CELL SUBSETS OF HIV+ PATIENTS ON CONTINUOUS cART 2022-12-14T13:08:51+00:00 Radoslava Emilova Yana Todorova Milena Aleksova Reneta Dimitrova Ivaylo Alexiev Lyubomira Grigorova Nina Yancheva Maria Nikolova <p><strong>Background:</strong> Reactive oxygen species (ROS) are generated at physiological levels as a result of cellular metabolism and contribute to cellular interaction and immune response. Elevated ROS may cause cell stress, damage, and apoptosis, and have been detected in different pathological states of infectious and non-infectious etiology.</p> <p><strong>Aim: </strong>To evaluate the association between intracellular ROS in T-cell subsets and HIV VL in chronic HIV infection.</p> <p><strong>Material and methods: </strong>Whole blood samples (Li-heparin, n=33) were analyzed during routine immune monitoring in two groups of HIV+ patients: A (n=21), on continuous cART for at least 2y, with sustained viral suppression (HIV VL&lt;40 copies/ml) and group B (n=12) on cART for less than 2y, average HIV VL 92330 c/ml. Percentage and absolute counts (AC) of CD4+ and CD8+T cells were determined by flow cytometry (Multitest, BD Trucount™ tubes, FACS Canto II). Fluorometric ROS assay kit (Sigma-Aldrich) was adapted for flow cytometry analysis to detect intracellular ROS in CD4+ and CD8+ T-cells (FACSDiva 6.1.2).</p> <p><strong>Results:</strong> The average CD4AC did not differ significantly between group A and B (714 vs. 568, p&gt;0.05), unlike the CD4/CD8 ratio (1.2 vs. 0.6, p&lt;0.01). The mean fluorescence intensity (MFI) of CD4+T intracellular ROS was significantly lower in group A (mean MFI 1744 vs. 2492, p&lt;0.05), unlike the CD8+T cell ROS content (1753 vs. 2129, p&gt;0.05). Noteworthy, CD4+T intracellular ROS correlated positively with HIV VL (R=0.5, p&lt;0.05), unlike CD8+T ROS. On the other hand, positive correlations between CD8+T ROS and cART duration, as well as age (R=0.5, p&lt;0.05 for both) were observed in group A.</p> <p><strong>Conclusions:</strong> CD4+T ROS production may be an indicator of residual HIV activity in the settings of undetectable HIV VL. The combined effects of ageing and long-term cART affect mostly the CD8+T cell compartment.</p> 2022-10-14T00:00:00+00:00 Copyright (c) 2022 Radoslava Emilova, Yana Todorova, Milena Aleksova, Reneta Dimitrova, Ivaylo Alexiev, Lyubomira Grigorova, Nina Yancheva, Maria Nikolova (Author) COMPARATIVE ASSESSMENT OF THE NUMBER AND IMMUNOLOGICAL STATUS OF NEWLY DIAGNOSED AND RE-ENROLLED IN CARE HIV+ IN THE PERIOD 2018–2019 AND 2020-2021 2022-12-14T13:09:07+00:00 Petar Vasilev Tanya Velyanova Ivan Baltadzhiev Mariyana Stoycheva <p><strong>BACKGROUND: </strong>HIV infection has not been shown to be an individual risk factor, but people living with HIV and co-morbidities are at increased risk of severe COVID-19. For HIV+ individuals with severe immunosuppression and/or uncontrolled viremia, the prognosis for the course and outcome of COVID-19 remains serious. HIV infected with low CD4+ T-cell counts before antiretroviral therapy (ART) had a higher risk of complications from COVID-19 than those with higher CD4+ T-cell counts.</p> <p>The aim of the study is to make a comparative assessment of the number and immunological status of newly registered and re-enrolled in care people living with HIV in the period 2018-2019 and 2020-2021 and to look for a correlation with COVID-19 pandemic .</p> <p><strong>MATERIALS AND METHODS</strong>: The study included all people living with HIV, monitored at the Clinic of Infectious Diseases and Parasitology, “St. George” University Hospital - Plovdiv both newly diagnosed and re-enrolled in care. Patients were divided into two groups: (1) Evaluated between 01.01.2018 and 31.12.2019 and (2) between 01.01.2020 and 15.10.2021. For the purposes of the study, methods of epidemiological and clinical analysis, ELISA, Western Blot for the diagnosis of HIV/AIDS and flow cytometry for the determination of T-cell populations were used.</p> <p><strong>RESULTS</strong>: For the period 2018-2019, there were 82 newly diagnosed and 29 re-enrolled in care HIV + patients. In 42,5% (35/82) of the newly diagnosed the number of CD4 cells was over 350 cells/ µl, in 19.5% (16/82) - between 200 and 350 cells/ µl, in 7% (6/82) - between 100 and 200 cells/ µl l and in 31% (25/82) below 100 cells/ µl. In 24% (7/29) of the re-enrolled the number of CD4 cells was above 350 cells/ µl, in 7% (2/29) - between 200 and 350 cells/ µl, in 21% (6/29) - between 100-200 cells/ µl and in 48% (14/29) - below 100 cells/ µl. For the period 2020-2021, there were 63 newly diagnosed and 34 re-enrolled in care HIV + patients. In 46% (29/63) of the newly diagnosed the number of CD4 cells was over 350 cells/ µl, in 21% (13/63) - between 200 and 350 cells/ µl, in 14% (9/63) -between 100 and 200 cells/ µl and in 19% (12/63) - below 100 cells/ µl. In 30 % (10/34) of the restarted, the number of CD4 cellswas over 350 cells/ µl, in 11% (4/34) - between 200 and 350 cells/ µl, in 15% (5/34) between 100 and 200 cells/ µl and in 44% (15/34) of patients - less than 100 cells/ µl</p> <p><strong>IN CONCLUSION</strong>: During the period 2020-2021, 10% fewer new HIV + patients were registered as compared to the period 2018-2019. The late presenters, with CD4 &lt;350 cells/ µl were 58% in the period 2018-2019 vs. 54% in the period 2020 -2021. The late presenters with advanced immune deficiency (CD4 &lt;100cells / µl) were respectively 31% and 19%. The proportion of those re-enrolled in care with advanced immune deficiency (CD4 &lt;100/ml) was 48% in the first group and 44% in the second group, respectively. The lower number of newly diagnosed HIV + patients could be explained with the fear of visiting hospitals, testing getting infected with SARS CoV-2. According to our data, Covid-19 pandemic did not significantly affect the immune status of people living with HIV .</p> 2022-10-14T00:00:00+00:00 Copyright (c) 2022 Petar Vasilev, Tanya Velyanova, Ivan Baltadzhiev, Mariyana Stoycheva (Author) PREVALENCE OF PHARYNGEAL AND RECTAL CHLAMYDIA TRACHOMATIS AND NEISSERIA GONORRHOEAE INFECTIONS AMONG MSM IN SOFIA, BULGARIA 2022-12-14T13:08:56+00:00 Ivva Philipova Elena Birindjieva Alexander Milanov Savina Stoitsova <p><strong>Abstract</strong>: Sexually transmitted infections (STIs) caused by <em>Chlamydia trachomatis</em> and <em>Neisseria gonorrhoeae</em> continue to be a major public health problem. Although they mainly affect the urogenital tract, <em>N. gonorrhoeae</em> and <em>C. trachomatis</em> can also be found in the pharynx and rectum. As data on extragenital chlamydia and gonorrhea in Bulgaria are still scarce, this study aimed to (1) determine the prevalence of pharyngeal and rectal infections with <em>C. trachomatis</em> and <em>N. gonorrhoeae</em> among men who have sex with men (MSMs) from Sofia and (2) to identify risk factors related to these infections to support screening recommendations based on scientific evidence. One hundred and fifteen MSM aged 16-50 were tested by systematic sampling during a visit to a sexual health center for voluntary and confidential HIV testing in Sofia. A questionnaire was used to collect demographics and risk factors, and clinical material from three anatomical sites: pharynx, rectum, and urogenital tract (first void urine or urethral swab) was examined to detect <em>C. trachomatis</em> and <em>N. gonorrhoeae</em> infections. The prevalence of <em>C. trachomatis</em> was 8.7% in the rectal samples tested, and the prevalence of <em>N. gonorrhoeae</em> was 0.9% and 5.2% in the pharyngeal and rectal samples, respectively. Local symptoms were reported in only 16.6% of rectal gonococcal infections and in 20% of <em>C. trachomatis</em> rectal infections. Patients reporting multiple partners had a significantly higher risk of being positive (OR = 3.8, 95% CI 1.03-14). The risk of HIV-positive MSM and those having unsafe sex was also higher (OR = 1.9 95% CI 0.19-20 and OR = 4.6 95% CI 0.98-21, respectively), but the findings were not statistically significant. Overall, more than 80% of extragenital infections would remain undetected and therefore transmissible if only symptomatic cases were investigated. These results suggest that in Bulgaria HIV-positive MSM and those having multiple sexual partners and unprotected sex would benefit from screening for extragenital STIs. Larger sample surveys could provide a better characterization of risk factors to guide screening choices.</p> 2022-10-14T00:00:00+00:00 Copyright (c) 2022 Ivva Philipova, Elena Birindjieva, Alexander Milanov, Savina Stoitsova (Author) CURRENT APPROACHES TO CONTROL OF ISONIAZID-RESISTANT TUBERCULOSIS 2022-12-14T13:09:02+00:00 Vladimir Milanov Nikolay Yanev Natalia Gabrovska Denitsa Dimitrova Elizabeta Bachiyska Vania Youroukova <p>Isoniazid (H; INH) is an important first-line drug for the treatment of active tuberculosis (TB) and latent TB infection because of its potent early bactericidal activity against <em>Мycobacterium tuberculosis</em>. Currently, TB resistant to INH, alone or in combination with other drugs, is the most common type of drug-resistant TB.</p> <p>Epidemiology of INH-resistant TB, the molecular mechanisms of drug resistance, current methods for diagnosis and therapeutic regimens of this TB form are presented.</p> <p>Studies in the last years have shown that resistance to INH reduces the probability of treatment success and increases the risk of acquiring resistance to other impor­tant first-line drugs.</p> <p>Based on the most recent meta-analyses, the last WHO recommendations for treatment of INH-resistant TB are to include rifampicin (RIF), ethambutol, pyrazinamide and levofloxacin for 6 months, and not to add streptomycin or other injectable agents to the drug regimen. The guideline emphasizes the importance of excluding resistance to RIF before starting the regimen for INH-resistant TB because of the risk for development of multidrug-resistant TB during the treatment course.</p> <p>The WHO recommendations are based on observational studies, not randomized controlled trials, and are thus conditional and based on low certainty in the estimates of effect. There­fore, further work is needed to optimize the treatment and control of INH-resistant TB.</p> 2022-10-14T00:00:00+00:00 Copyright (c) 2022 Vladimir Milanov, Nikolay Yanev, Natalia Gabrovska, Denitsa Dimitrova, Elizabeta Bachiyska, Vania Youroukova (Author) STUDY ON TICKS REMOVED FROM PATIENTS FOR INFECTION WITH BORRELIA BURGDORFERI AND THEIR NUMBER DEPENDING ON TEMPERATURE AND PRECIPITATION IN 2016-2021 2022-12-14T13:09:04+00:00 Teodora Gladnishka Iva Christova Iva Trifonova Vladislava Ivanova Elitsa Panayotova Evgenia Taseva <p><strong>Background: </strong>Deacarization, applied epidemiological measures, and climatic factors affect the abundance of ticks. On the other hand, ticks themselves are a factor of great epidemiological and epizootic importance. Studies concerning the influence of climatic factors on ticks and their infection with <em>B. burgdorferi</em> are still limited in Bulgaria. The aim was to investigate the abundance of ticks in relation to temperature and precipitation, as well as the infection with <em>B. burgdorferi </em>of ticks removed from patients during the period 2016-2021.</p> <p><strong>Materials/methods: </strong>A total of 10,907 ticks were collected from patients and classified according to species and stage of development. Nested PCR was performed targeting two sites of the spacer region between 5S and 23S of <em>B. burgdorferi</em> sensu lato rRNA. Weather data were collected from free Internet meteorological sites.</p> <p><strong>Results:</strong> It was found that 92-96% of the ticks belonged to the species <em>Ixodes ricinus.</em> PCR data were obtained for infestation of ticks in 2016-2021. Only in 2018, the highest number of ticks was observed in May, while in the other five years - in June, which was analyzed in relation to the average temperature and precipitation.</p> <p><strong>Conclusion:</strong> An increase in tick abundance was observed at average temperatures around 20°C, with rainfall on the days before the peak. During the 6-year period, the highest number of ticks was collected in June 2021, which could be explained with the high average temperatures and abundant precipitations during the preceeding spring months (April – June).</p> 2022-10-14T00:00:00+00:00 Copyright (c) 2022 Teodora Gladnishka, Iva Christova, Iva Trifonova, Vladislava Ivanova, Elitsa Panayotova, Evgenia Taseva (Author) A RETROSPECTIVE STUDY ON THE DISTRIBUTION OF E. COLI ENTERITIS IN BULGARIA FOR A PERIOD OF TEN YEARS (2011-2020) 2022-12-14T13:08:59+00:00 Maria Pavlova Ekaterina Alexandrova ealexandrova@pipd.pd Galin Kamenov Metodi Popov mpopov@pipd.pd <p><strong>BACKGROUND.</strong> Intestinal diseases caused by diarrheagenic <em>E. coli</em> account for a significant proportion of infections, especially in children. <em>E. coli</em> enteritis can occur as sporadic cases but often assumes an epidemic nature. This study aims to determine the significance and prevalence of infections caused by diarrheagenic <em>E. coli</em> in Bulgaria for a period of ten years 2011-2020. <strong>MATERIALS AND METHODS.</strong> The etiological role and distribution of diarrheagenic <em>E. coli</em> among Bulgarian population for the last decade were determined by a retrospective analysis of microbiological and epidemiological data. <strong>RESULTS.</strong> Data from the studied period reveal the role of enterotoxigenic <em>E. coli</em> (ETEC) O6 as a leading etiological cause of epidemic and sporadic enteritis in the country, followed by enteropathogenic <em>E. coli</em> (EPEC) O126 and O127. There are only two reported cases of lethal hemorrhagic uremic syndrome (HUS) caused by enterohemorrhagic <em>E. coli</em> (EHEC) that happened in 2011. Most affected by diarrheagenic <em>E. coli</em> (DEC) infections are infants and young children. Neonatal meningitis in Bulgaria is rare, the etiological agents are <em>E. coli</em> O18 and O25. The most common registered DEC infections are during the summer months of May - September. Several epidemics have been registered in young children, and the etiological cause is ETEC O6. <strong>CONCLUSION. </strong>The main etiological agent of <em>E. coli</em> infections in Bulgaria is ETEC O6, and infants and young children are at risk. Recent DEC epidemics have not been reported. The ethiologic diagnosis of infections is underestimated, which is a risk factor for increasing the number of healthy carriers, outbreaks and unlimited agent spreading through the food chain.</p> 2022-10-14T00:00:00+00:00 Copyright (c) 2022 Maria Pavlova, Ekaterina Alexandrova, Galin Kamenov, Metodi Popov (Author)