Infekcija virusom Zapadnog Nila s neurološkim poremećajima: prikaz slučaja i kratak pregled stanja u Bugarskoj

A case of a 66-year-old man with West Nile neuroinvassive disease manifested with fever, weakness, fa-tigue, consciousness disorders and underlying diabetes mellitus type 2 and cardiovascular diseases is pre-sented. Laboratory data showed elevated erythrocyte sedimentation rate and fibrinogen. Serological tests revealed West Nile virus specific antibodies of class IgM and IgG in serum. West Nile virus RNA was de-tected in urine sample. Supportive therapy was applied.Prikazuje se slučaj 66-godišnjeg bolesnika s neuroinvazivnom bolešću Zapadnog Nila koja se manifestirala grozni-com, umorom, poremećajem svijesti uz osnovnu bolest dijabetesa tipa 2 i kardiovaskularnom bolešću. Laboratorij-ski podaci pokazali su povišenu sedimentaciju i fibrinogen. Serološki testovi utvrdili su protutijela specifična za virus Zapadnog Nila klase IgM i IgG u serumu. Virusna RNA otkrivena je u uzorku mokraće. Primijenjena je suportivna terapija

SARS-COV-2 SEROSURVEY AMONG BULGARIAN HEALTHCARE WORKERS BEFORE AND AFTER VACCINATION

Background: In the response to the current COVID-19 pandemic caused by the novel SARS-CoV-2, one of the groups at higher risk were healthcare workers (HCWs), especially those who worked on the frontline. The presence of SARS-CoV-2 specific IgG antibodies (seropositivity) in certain populations provides better understanding of virus circulation and transmission. Our aim was to study the seroprevalence rates of anti-SARS-CoV-2 antibodies among a group of healthcare workers before and after vaccination/COVID-19 infection. Material and Methods: We determined the presence of SARS-CoV-2 specific IgG and IgA antibodies against S-antigen of by ELISA method. In this study, we enrolled 74 healthcare workers and three months later, 48 of the participants were followed up. At the baseline, none of the participants was vaccinated or had suffered COVID-19.  Results: SARS-Cov-2 specific IgG antibodies were found in 32.4% of the participants. Higher prevalence of class IgA antibodies – 44.6% was detected. All samples that were IgG seropositive were also positive or borderline for IgA antibodies. Overall, virus-specific antibodies were not detected in 40.6% of HCWs in the group. During the follow-up (after vaccination and/or COVID-19 infection) high rates of both IgG and IgA seroprevalence were established. SARS-C0V-2 specific IgG antibodies were detected in 95.8% of the participants. Statistically significant difference was found in the levels of IgG and IgA antibodies both before and after vaccination, p<0.0001. Conclusions: Based on detection of anti-SARS-CoV-2 IgG antibodies, seroprevalence of 32.4% was established in an unvaccinated group of HCWs. Our survey demonstrated that asymptomatic COVID-19 infection may induce weaker humoral immune response, with production of IgA but not of IgG antibodies

SARS-COV-2 GENOMIC SURVEILLANCE IN BULGARIA INDICATES DIVERSE DYNAMICS DRIVEN BY MULTIPLE INTRODUCTIONS OF DIFFERENT VIRAL VARIANTS IN 2022

Background. Evolution of the emerging SARS-CoV-2 variants raises concerns about the possibility of accelerated transmission,  disease severity, diagnostic challenges, and reduced vaccine effectiveness in the ever-evolving COVID-19 pandemic worldwide. Objectives for this study were to build a comprehensive national system for monitoring and genomic surveillance of SARS-CoV-2  and to identify the introduced virus variants in the country. Methods. We analyzed SARS-CoV-2 infections in 7948 representative clinical samples collected in medical institutions in different  geographical regions of the country in 2022. Whole-genome next-generation sequencing of SARS-CoV-2 was performed on samples  from randomly selected SARS-CoV-2-positive individuals by using a modified ARTIC v3-tailed amplicon method. A bioinformatic and  phylogenetic analyses of the obtained sequences was carried out. Results. Significant dynamics was observed in the spread of viral variants in 2022, which is characterized by the introduction and  spread of multiple SARS-CoV-2 variants. The phylogenomic analysis identified a high genetic heterogeneiety composed of a total of 152 different viral clades divided into 3 main supergroups: 114 (75.0%) of which were Omicron sub-variants, 35 (23.0%) Delta sub-variants, and 3 (2.0%) recombinant forms. Conclusion. Viral variants and their sub-clades with different potentials to impact disease severity were identified and the  information was immediately published for use by decision-makers and the scientific community. The global pandemic of COVID-19  has shown the importance of molecular biological surveillance, which is an indispensable element of the modern approach in the  fight against infectious diseases

The Cultural and Historical Legacy of Acad. Stefan Mladenov (1880-1963)

The article is dedicated to the life and professional path of Acad. Stefan Mladenov (1880-1963) as commemoration of the 60th anniversary of his death. It summarizes the cultural and historical dimensions of his research, which has remained eternal in time. The emphasis is placed on his personal documents kept at the Scientific Archive of the Bulgarian Academy of Sciences (SA-BAS). They are described and analyzed in historical and research perspectives with a focun on those that are directly related to the Bulgarian-Polish scientific relations in the ifrst half of the 20th century. A list of the selected studies dedicated to the memory of Acad. Mladenov can be found after the article

Outbreak caused by NDM-1- and RmtB-producing Escherichia coli in Bulgaria

Twelve consecutive carbapenem-resistant Escherichia coli isolates were recovered from patients (infection or colonization) hospitalized between March and September 2012 in different units at a hospital in Bulgaria. They all produced the carbapenemase NDM-1 and the extended-spectrum-β-lactamase CTX-M-15, together with the 16S rRNA methylase RmtB, conferring high-level resistance to all aminoglycosides. All those isolates were clonally related and belonged to the same sequence type, ST101. In addition to being the first to identify NDM-producing isolates in Bulgaria, this is the very first study reporting an outbreak of NDM-1-producing E. coli in the world

A study of anti-SARS-CoV-2 antibodies among healthcare personnel and the general population

AbstractBulgaria, like many other countries, has experienced the far-reaching consequences of the Coronavirus disease 2019 (COVID-19) pandemic. Seroprevalence studies serve as a crucial method for assessing the exposure and immunity levels within a population. In this serosurvey, which is the first of this kind conducted in Bulgaria, we enrolled 104 healthcare workers (HCWs) from one front-line Bulgarian hospital and 237 individuals from the general population. Serum samples were collected in December 2021 from the general population and in February 2023 from HCWs and the general population. The presence of four anti-SARS-CoV-2 antibodies was evaluated: anti-Spike 1-IgG, anti-Nucleoprotein-IgG, anti-Spike1-IgA and anti-Recombinant binding domain neutralizing antibodies. Our results showed high percentages of seropositivity in both the HCWs and the general population (99% and 78%, respectively) in February 2023. HCWs had significantly higher mean IgA and mean anti-S1-IgG antibody levels compared to the general population. The seropositivity in the general population in December 2021 was 79%. The mean levels of IgA and anti-NCP-IgG were significantly higher, whereas the mean anti-S1-IgG levels were significantly lower in February 2023 compared to December 2021. We found a strong correlation between neutralizing antibodies and anti-S1-IgA and anti-S1-IgG antibodies for all tested groups. It is necessary to perform large-scale serosurveys to provide analysis of the seroprevalence in a larger population and its dynamics over time and to facilitate evidence-based strategies that will safeguard the health and well-being of the Bulgarian population and contribute to the global efforts in combating the COVID-19 pandemic

Increased resistance to carbapenems in proteus mirabilis mediated by amplification of the bla vim-1 -carrying and is 26 -associated class 1 integron

The aim of the study was to decipher the mechanisms and associated genetic determinants responsible for increased carbapenem resistance among Proteus mirabilis clinical isolates.Methods: The entire genetic structure surrounding the β- lactam resistance genes was characterized by PCR, gene walking, and DNA sequencing.Results: A series of clinical P. mirabilis isolates were consecutively recovered from different patients at the Military hospital of Sofia, Bulgaria. They showed variable levels of resistance to carbapenems. All isolates produced the same carbapenemase VIM-1 that was chromosomally encoded. We showed that increased resistance to carbapenems was related to an increased number of blaVIM-1 gene copies.Conclusion: We showed here that increased carbapenem resistance in P. mirabilis may result from increased expression of the blaVIM-1 carbapenemase gene through multiplication of its copy numbe

Fatal Case of West Nile Neuroinvasive Disease in Bulgaria

To the Editor: West Nile virus (WNV) is a mosquitoborne flavivirus. Approximately 80% of human infections are asymptomatic, 10%\u201320% are characterized by an acute febrile illness, and <1% by involvement of the central nervous system (West Nile neuroinvasive disease). Sporadic human cases and small outbreaks of West Nile fever were reported in Europe until the mid-1990s, when the first large outbreak occurred in Romania in 1996. Since then, and especially in recent years, sporadic human cases and outbreaks have been reported in other countries in Europe and neighboring countries on the Balkan Peninsula. A large outbreak of WNV lineage 2 infection occurred in Greece in 2010. Outbreaks have also been reported in other countries in Europe, which showed spread of WNV lineage 2. Some probable cases of West Nile fever were reported to the Bulgarian Ministry of Health on the basic of serologic test results. We report a case of fatal West Nile neuroinvasive disease in a man in Bulgaria. This case was confirmed by detection of specific antibodies against WNV and sequencing of the full virus genome

Antibody dynamics and viral load in COVID-19: differences in mild, moderate and severe cases

AbstractIn this study, we investigated the potential association between the severity of COVID-19 (coronavirus disease 2019) and nasopharyngeal viral loads or serum antibody levels and evaluate the temporal dynamics of antibodies against SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2). Using ELISA (enzyme-linked immunosorbent assay), we determined the presence of IgA, IgM and IgG antibodies in 450 serum samples from 122 patients for a period of 9 months after disease onset. Viral burden was quantified by RT-PCR (reverse transcription polymerase chain reaction) in 270 nasopharyngeal swab samples from 122 patients for a period of 4 weeks after the onset of the symptoms. Higher antibody values were generally seen in patients with moderate and severe disease compared to patients with mild COVID-19. Significant differences were established in IgA and IgG antibody levels at weeks 3–4 and 5–13 after the disease onset. In all severity groups, seroconversion rates were high and a similar pattern was observed with IgM antibodies quickly decreasing after reaching peak levels and IgA and IgG antibodies persisting at high values up to 9 months. The mean viral loads were higher in the mild group during the first 2 weeks and in the moderate and severe groups later on. However, the differences were not statistically significant. The IgA and IgG antibody response was significantly stronger in patients with moderate/severe disease around the time of peak antibody production as well as in vaccinated patients. No definitive association between viral load levels and the severity of COVID-19 was observed

Age and Gender Trends in the Prevalence of Markers for Hepatitis E Virus Exposure in the Heterogeneous Bulgarian Population

The prevalence of hepatitis E virus (HEV) in the Bulgarian population remains underestimated. The aim of the present study was to evaluate age and gender trends in HEV prevalence in the heterogeneous Bulgarian population. Stored serum samples from blood donors and different patient sub-populations—kidney recipients (KR), patients with Guillain–Barre syndrome (GBS), Lyme disease (LD), patients with liver involvement and a clinical diagnosis other than viral hepatitis A and E (non-AE), hemodialysis (HD) and HIV-positive patients (HIV)—were retrospectively investigated for markers of past and recent/ongoing HEV infection. The estimated overall seroprevalence of past infection was 10.6%, ranging from 5.9% to 24.5% for the sub-populations evaluated, while the seroprevalence of recent/ongoing HEV infection was 7.5%, ranging from 2.1% to 20.4%. The analysis of the individual sub-populations showed a different prevalence with respect to sex. In regard to age, the cohort effect was preserved, as a multimodal pattern was observed only for the GBS sub-population. Molecular analysis revealed HEV 3f and 3e. The type of the population is one of the main factors on which the anti-HEV prevalence depends, highlighting the need for the development of guidelines related to the detection and diagnosis of HEV infection with regard to specific patient populations