PROBLEMS of Infectious and Parasitic Diseases <p style="text-align: justify;"><strong>"PROBLEMS of Infectious and Parasitic Diseases"</strong> <span id="result_box" class="" lang="en">is <span class="">a peer-reviewed journal of</span> NCIPD's scientific papers published in English on paper and in digital form, with periodicity two books <span class="">a year</span></span>.</p> <p style="text-align: justify;"><span id="result_box" class="" lang="en">The journal <span class="">received</span> international acclaim and since 1997 has established itself as referenced <span class="">edition</span> in <strong>Exerpta Medica</strong>, and since 2008 - in <span class=""><strong>SCOPUS</strong>.</span></span></p> en-US (Iva Christova, MD, DSc) (Ivo Georgiev) Tue, 12 May 2020 15:56:20 +0000 OJS 60 IN SILICO DEVELOPMENT OF HIGH-RESOLUTION MLVA TYPING SCHEME FOR ENTEROCOCCUS FAECIUM <p>Emergence of enterococci as nosocomial pathogens is frequently associated with hospital outbreaks. Vancomycin resistance is especially perturbing as it limits the possible therapeutic options. Based on vast in silico analysis, we introduce a new multiple-locus variable-number tandem repeat analysis (MLVA) scheme for genotyping of Enterococcus faecium isolates, parameters of which are comparable to these of pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The scheme was tested in silico on all available at this time E. faecium genomes in NCBI Genbank. Searching for suitable variable number of tandem repeats (VNTR) loci was conducted with a set of free access applications. Ten VNTR loci were selected according to their polymorphic structure and stability using the Primer-BLAST utility of NCBI. Primers were designed to be compatible in a multiplex reaction and the method was adapted for high resolution separation techniques. As a result, a total of 60 MLVA profiles and 35 MLST profiles were generated from the analysis of 114 sequenced genomes. Minimum spanning trees were created for both MLVA and MLST in order to analyze the genetic relatedness between isolates. Hunter Gaston discriminatory index was measured for both MLVA (0,959) and MLST (0,926). Typeability was also measured for both methods (MLVA – 85.9%; MLST – 89.4%). These results suggest that the new MLVA scheme is suitable for epidemiological studies of hospital-adapted E. faecium isolates.</p> Ivan Stoikov, Assoc. Prof. Ivan Ivanov, Stefana Sabtcheva Copyright (c) 2020 PROBLEMS of Infectious and Parasitic Diseases Tue, 12 May 2020 00:00:00 +0000 ANTIMICROBIAL SUSCEPTIBILITY OF S. PNEUMONIAE STRAINS ISOLATED FROM CHILDREN WITH NASOPHARYNGEAL CARRIAGE <p><em>Streptococcus pneumoniae</em> colonises the nasopharynx of children and could cause life-threatening diseases. As a result of the implementation of conjugate vaccines worldwide the spread of vaccine serotypes has decreased. In Bulgaria PCV10 was introduced in 2010 followed by changes in the invasive clones carrying resistance genes. The aim of our study is to determine the serotype distribution and resistance patterns of isolates from children carriers after vaccination. A total of 834 children were tested for <em>S. pneumoniae</em> and 21% showed positive culture results. All isolates were genotyped with PCR. We found that 85% of the positive samples are from children attending kindergartens and schools. The most frequent serotypes/serogroups were 6C (20%) and 24B/F (11.5%), followed by 3 (8.6%), 11A/D (8%), 35F (6.9%), 19A (6.3%), 23A (6.3%) and 15A/F (6.3%). The susceptibility to β-lactams was high and there were strains showing intermediate susceptibility to benzylpenicillin. This study found 76 (44%) MDR strains non-susceptible to at least 3 antibiotic classes and the most common resistance pattern was erythromycin-clindamycin-tetracycline.</p> Mariya Malcheva, Iva Philipova, Chief Assistant Ivan Simeonovski, PhD, Assoc. Prof. Viktoriya Levterova, PhD, Nadyia Brankova, Prof. Todor Kantardjiev, MD Copyright (c) 2020 PROBLEMS of Infectious and Parasitic Diseases Tue, 12 May 2020 00:00:00 +0000 ISONIAZID - MONORESISTANT TUBERCULOSIS IN BULGARIA <p><strong>Background.</strong> Isoniazid is a common drug in the treatment regimens for TB infection. Monoisoniazid resistance reduces the probability of a successful treatment outcome and increases the risk of acquiring additional drug resistance.</p> <p><strong>Material and methods.</strong> For the period 2015-2016 a total of 36 TB cases were confirmed in NRL TB, Sofia, as isoniazid-monoresistant <em>Mycobacterium tuberculosis</em> complex. Minimum inhibitory concentration testing for isoniazid was conducted with BАСТЕС MGIT 960 System in the following concentrations of the drug: 0.1 μg/ml, 0.15μg/ml, 0.2μg/ml, 0.3μg/ml, 0.4μg/ml. Molecular testing was performed with GenoType ® MTBDRplus in order to detect the most common mutations associated with resistance to isoniazid.</p> <p><strong>Results.</strong> Only 25% of the tested <em>M. tuberculosis </em>complex isolates with phenotypic isoniazid monoresistance had the S315T1 mutation in <em>katG</em>; all isolates were with MIC over 0.4 μg/ml. C15T in the promoter region of <em>inhA</em> was detected in 22.22% of cases and only 1 of them showed MIC below 0.4 μg/ml. No mutations were detected in nearly half of the cases (n=19, 52.78%) and most of these isolates were with lower MIC values (n=12). Conclusion. The rapid testing with GenoType ® MTBDRplus can be used as a screening procedure indicating whether further examination of isoniazid MIC is relevant in resistant <em>M. tuberculosis</em> and whether higher doses could be considered.</p> Stanislava Yordanova, PhD, Ana Baykova, Yuliana Atanasova, Yana Todorova, Assoc. prof. Elizabeta Bachiyska, MD, PhD Copyright (c) 2020 PROBLEMS of Infectious and Parasitic Diseases Tue, 12 May 2020 00:00:00 +0000 MOLECULAR EPIDEMIOLOGICAL ANALYSIS OF THE TRANSMISSION CLUSTERS OF THE HIV-1 CIRCULATING RECOMBINANT FORMS CRF01_AE AND CRF02_ AG IN BULGARIA <p><strong>Background</strong>. The purpose of this study was to analyse the underlying HIV transmission clusters of individuals from different vulnerable groups infected with the recombinant forms of HIV-1 – CRF01_AE and CRF02_AG, between 1986 and 2011 using sequencing and phylogenetic analysis.</p> <p><strong>Material and methods</strong>. Blood samples from randomly selected 242 individuals diagnosed with HIV-1 CRF01_AE and CRF02_AG in Bulgaria were analysed. HIV-1 pol gene fragment was sequenced using the ViroSeq HIV-1 Genotyping Test (Abbott) and/or TruGene DNA Sequencing System. The phylogenetic tree reconstruction was performed with the IQ-TREE program. Identification of the phylogenetic clusters was performed using the ClusterPicker program with two parameters to identify recent and distant infection. </p> <p><strong>Results</strong>.Two main local independent epidemics confined to different geographical regions of the country were caused by HIV-1 CRF01_AE and CRF02_AG. The various viral strains circulate predominantly in two major separate regions – CRF01_AE in Sofia and CRF02_AG in Plovdiv. Most of the individuals infected with viral strains analysed in this study were people who inject drugs (PWID) or heterosexuals and only a few were men who have sex with men. The phylogenetic analysis revealed transmission clusters in both recombinant forms, few in number when confined within a short period of time and multiple clusters over an extended timeframe. </p> <p><strong>Conclusions. </strong>The introduction and rapid spread of two different strains of HIV-1 into geographically distant groups of PWID triggered local epidemic outbreaks. The phylogenetic analysis indicated the accelerated transmission of HIV, which is a characteristic of the spread through injection practices. Our study demonstrated that transmission cluster monitoring is important for better understanding of the development of epidemic and could be used as a tool for the identification of risk indicator populations.</p> Assoc. Prof. Ivailo Alexiev, PhD, Reneta Dimitrova, Anna Gancheva, Asya Kostadinova, Lyubomira Grigorova, Aleksandra Partsuneva, I. Elenkov, N. Yancheva, M. Stoycheva, T. Doychinova, L. Pekova, Radoslava Emilova, Prof. Maria Nikolova, MD, DSci Copyright (c) 2020 PROBLEMS of Infectious and Parasitic Diseases Tue, 12 May 2020 00:00:00 +0000 PREVALENCE OF ANTI-HBC IN HBSAG-NEGATIVE POPULATION <p><strong>Background.</strong> Among the various serological markers employed in the hepatitis B virus (HBV) differential laboratory diagnosis, serum HBsAg is considered the most reliable. In order to characterise the HBV infection, another important diagnostic marker is employed – the HBc antibody (anti-HBc). There are three categories of anti-HBc-positive individuals: patients with HBV immunity, patients with chronic HBV and individuals with the so-called isolated anti-HBc pattern. The current study aimed to evaluate the presence of anti-HBc in patients negative for HBsAg whose clinical diagnosis was acute viral hepatitis.</p> <p><strong>Material and methods.</strong> A total of 88 specimens were examined, of which 75 sera were from prospective patients diagnosed with acute viral hepatitis, and 13 sera from breast milk donors. Antibodies against the hepatitis B core antigen were detected by enzyme-linked immunosorbent assay (ELISA).</p> <p><strong>Results.</strong> Twenty-eight (32%) of all tested samples were positive for anti-HBc. Nineteen samples belonged to male and 9 to female patients. One positive sample was from a breast milk donor. Two age groups, namely 46-55 years and 56-65 years, demonstrated the highest rate of anti-HBc positivity. Among the other age groups positivity rates varied from 15% to 36%. The results demonstrated a linear trend of increasing anti-HBc prevalence with increasing age.</p> <p><strong>Conclusions.</strong> Considering the highest rate of anti-HBc positivity being demonstrated in the age range 46-65 years, it could be assumed that a sufficient number of risk factors accumulate over time resulting in greater population susceptibility to HBV infection.</p> Daniel Ivanov, TenchoTenev, MD, Assistant Professor Elica Golkocheva-Markova,PhD Copyright (c) 2020 PROBLEMS of Infectious and Parasitic Diseases Wed, 13 May 2020 00:00:00 +0000 RETROSPECTIVE ANALYSIS OF TAENIASIS IN BULGARIA CAUSED BY THE BEEF TAPEWORM FOR THE PERIOD 2008-2017 <p><strong>The aim</strong> of the present study is to analyse the dynamics of the distribution of taeniasis caused by the beef tapeworm (<em>Taeniarhynchus saginatus</em>) among the population of Bulgaria for the period 2008-2017.</p> <p><strong>Material and methods.</strong> The analysis is based on laboratory and clinical data on patients diagnosed with taeniarhynchosis in DPTM at NCIPD, as well as data from epidemiological studies carried out by RHIs in accordance with the current legislation in the country.</p> <p><strong>Results.</strong> For the studied period, cases of human taeniarhynchosis were reported from 21 districts of the country, with 246 infected persons. The areas with the highest number of cases during the whole period were Shumen – 14.6%, Plovdiv – 13.8%, Targovishte – 10.9 and Sofia – 10.6%. Annual morbidity ranges from 0.63 per 100 000 (2008) to 0.23 per 100 000 (2017), with average morbidity of 0.37%<sub> 000</sub>. The prevalence was higher among female subjects (61%), and the distribution by age showed a significantly higher incidence in adults (88%) compared to the group of children and adolescents (22%). The most affected were the age groups 35-39 (11.79%) and 55-59 (11.38%) years. Patients of different ethnic origin represent 54% of cases.</p> <p><strong>Conclusion.</strong> Data from our study shows that cases of taeniarhynchosis, even though sporadic, are reported annually in the country. The distribution is highest in regions with well-developed private livestock farming and high rate of home meat production without veterinary control. Poor health literacy of the population resulting in environmental contamination with human excreta and the possibility of infection of intermediate hosts, as well as consumption of uncooked homemade products and insufficient veterinary health control mainly contribute to the endemic spread of taeniarhynchosis in the country.</p> Mihaela Videnova, Assoc. Prof. Rumen Harizanov, MD, PhD, Nina Tsvetkova, Raina Borisova, MD, Assoc. Prof. Iskra Rainova, Aleksandra Ivanova Copyright (c) 2020 PROBLEMS of Infectious and Parasitic Diseases Tue, 12 May 2020 00:00:00 +0000 A CASE OF VIBRIO VULNIFICUS INFECTION IN A DIABETES PATIENT WITH FATAL OUTCOME <p><strong>Aim.</strong> The aim of this report is to present the case of a 44-year-old male tourist from Belgium with type 1 diabetes who developed necrotizing fasciitis and sepsis caused by <em>Vibrio vulnificus</em> during his stay at the Bulgarian Black Sea Coast.</p> <p><strong>Material and methods.</strong> Data was collected from the patient's examination records. <em>V. vulnificus</em> was isolated by culture on blood agar and identified with biochemical tests.</p> <p><strong>Results.</strong> During the initial hospitalisation the patient left the clinic without leave and returned 24 hours later. He was surgically treated and supported with intensive care. However, the patient developed severe sepsis which resulted in fatal outcome.</p> <p><strong>Conclusion.</strong> It is important to highlight the need for sufficient awareness among patients with diabetes and other serious chronic diseases of the potential threat posed by <em>V. vulnificus</em> infections.</p> Maria Pavlova, PhD, K. Tsankova, Rumiana Nenova, MD, Iskra Tomova, V. Velev, S. Shishkov, Prof. Todor Kantardjiev, MD Copyright (c) 2020 PROBLEMS of Infectious and Parasitic Diseases Tue, 12 May 2020 00:00:00 +0000