Journal of medical microbiology最新文献

Introduction. After two seasons of absence and low circulation, influenza activity increased significantly in the winter of 2022-2023. This study aims to characterize virological and epidemiological aspects of influenza infection in Bulgaria during the 2022-2023 season and perform a phylogenetic/molecular analysis of the hemagglutinin (HA) and neuraminidase (NA) sequences of representative influenza strains.Hypothesis/Gap Statement. Influenza A and B viruses generate new genetic groups/clades each season, replacing previously circulating variants. This results in increased antigenic distances from current vaccine strains. Strengthening existing influenza surveillance is essential to meet the challenges posed by the co-circulation of influenza and SARS-CoV-2.Methodology. We tested 2713 clinical samples from patients with acute respiratory illnesses using a multiplex real-time RT-PCR kit (FluSC2) to detect influenza A/B and Severe acute respiratory syndrome coronavirus-2(SARS-CoV-2) simultaneously. Representative Bulgarian influenza strains were sequenced at the WHO Collaborating Centres in London, UK, and Atlanta, USA.Results. Influenza virus was detected in 694 (25.6 %) patients. Of these, 364 (52.4 %), 213 (30.7 %) and 117 (16.9 %) were positive for influenza A(H1N1)pdm09, A(H3N2) and B/Victoria lineage virus, respectively. HA genes of the 47 influenza A(H1N1)pdm09 viruses fell into clades 5a.2. and 5a.2a.1 within the 6B.5A.1A.5a.2 group. Twenty-seven A(H3N2) viruses belonging to subclades 2b, 2a.1, 2a.1b and 2a.3a.1 within the 3C.2a1b.2a.2 group were analysed. All 23 sequenced B/Victoria lineage viruses were classified into the V1A.3a.2 group. We identified amino acid substitutions in HA and NA compared with the vaccine strains, including several substitutions in the HA antigenic sites.Conclusion. The study's findings showed genetic diversity among the influenza A viruses and, to a lesser extent, among B viruses, circulating in the first season after the lifting of anti-COVID-19 measures.

Clostridioides difficile is the most common cause of nosocomial antibiotic-associated diarrhoea and is responsible for a spectrum of diseases characterized by high levels of recurrence and morbidity. In some cases, complications can lead to death. Currently, several types of animal models have been developed to study various aspects of C. difficile infection (CDI), such as colonization, virulence, transmission and recurrence. These models have also been used to test the role of environmental conditions, such as diet, age and microbiome that modulate infection outcome, and to evaluate several therapeutic strategies. Different rodent models have been used successfully, such as the hamster model and the gnotobiotic and conventional mouse models. These models can be applied to study either the initial CDI infectious process or recurrences. The applications of existing rodent models and their advantages and disadvantages are discussed here.

Introduction. Administered nasally, spores of the Gram-positive bacterium Bacillus subtilis have been shown to be able to induce innate immunity sufficient to confer protection to influenza and respiratory syncytial virus.Hypothesis. Although members of the aerobiome, intranasal delivery of high numbers of live spores carries potential safety issues.Aim. To address the potential safety risk of using live spores, we assessed the safety of spores that had been completely inactivated using heat sterilization.Methodology. Using autoclaved, and therefore killed, spores of a generally recognized as safe-notified B. subtilis strain (DSM 32444), safety was assessed in vitro (biotype, genome and cell based cytoxicity) and in vivo, using intranasal administration in rodent models and lastly in human volunteers.Results. Using a 15-day, repeat-dose, regimen in a rodent model, no indication of toxicity was observed. In a registered human study (NCT05984004), a formulated preparation of inactivated DSM 32444 spores referred to as SPEROVID was developed, and tolerance in human volunteers was assessed following 7 days of nasal dosing (2-4 times/day).Conclusion. Our study demonstrated that in humans an intranasal dose of up to 3×10⁸ killed spores was safe and well tolerated.

The role of meteorological factors, such as rainfall or temperature, as key players in the transmission and survival of infectious agents is poorly understood. The aim of this study was to compare meteorological surveillance data with epidemiological surveillance data in Belgium and to investigate the association between intense weather events and the occurrence of infectious diseases. Meteorological data were aggregated per Belgian province to obtain weekly average temperatures and rainfall per province and categorized according to the distribution of the variables. Epidemiological data included weekly cases of reported pathogens responsible for gastroenteritis, respiratory, vector-borne and invasive infections normalized per 100 000 population. The association between extreme weather events and infectious events was determined by comparing the mean weekly incidence of the considered infectious diseases after each weather event that occurred after a given number of weeks. Very low temperatures were associated with higher incidences of influenza and parainfluenza viruses, Mycoplasma pneumoniae, rotavirus and invasive Streptococcus pneumoniae and Streptococcus pyogenes infections, whereas very high temperatures were associated with higher incidences of Escherichia coli, Salmonella spp., Shigella spp., parasitic gastroenteritis and Borrelia burgdorferi infections. Very heavy rainfall was associated with a higher incidence of respiratory syncytial virus, whereas very low rainfall was associated with a lower incidence of adenovirus gastroenteritis. This work highlights not only the relationship between temperature or rainfall and infectious diseases but also the most extreme weather events that have an individual influence on their incidence. These findings could be used to develop adaptation and mitigation strategies.

Introduction. At the end of 2019 and the year before, there was a significant spread of measles in the World Health Organization (WHO) European Region.Gap statement. Among the countries that reported, a measles outbreak was Bosnia and Herzegovina (BiH).Aim. To describe the measles outbreak in BiH (an entity of the Federation of BiH, FBiH) in 2019.Methodology. Confirmatory IgM serology, measles nucleic acid detection by real-time RT-PCR and virus genotyping were done in the WHO-accredited laboratory for measles and rubella at the Clinical Center of the University of Sarajevo, Unit for Clinical Microbiology. Genotype was determined in all measles-RNA-positive cases by sequence analysis of the 450 nt fragment coding the C-terminal of measles virus nucleoprotein (N).Results. From 1 January to 31 December 2019, 1332 measles cases were reported, with the peak observed in April 2019 (413/1332, 31.01 %). Sarajevo Canton had the highest incidence, number of cases and percentage (206.4; 868/1332; 65.17 %) of measles cases. Around four-fifths of infected persons were unvaccinated (1086/1332, 81.53 %), while 4.58 % of the patients (61/1332) were immunized with one dose of measles-containing vaccine. The highest proportion of cases was found in children 0-6 years of age (738/1332, 55.41 %). Measles IgM positivity was determined in 75.88 % (346/456), while virus RNA was detected in 82.46 % (47/57) of the swab samples. All measles virus sequences belonged to genotype B3. SNP (position 216: C=>T) was detected in 1 of the 40 sequences obtained during this outbreak.Conclusion. Due to suboptimal immunization coverage, BiH belongs to countries at a high risk for measles outbreaks. Post-COVID-19 (coronavirus disease 2019) pandemic, targeted and tailored strategies are required to ensure routine vaccination demand and acceptance and broad partner and stakeholder group participation.

Between March and October 2022, a peak of detection of Bordetella parapertussis by qPCR, real-time PCR was observed in France.Hypothesis/Gap Statement. Whether this peak was due to resurgence from previous circulating lineages or reintroduction into the country was unknown.Objective. The objective of this study is to understand B. parapertussis-transient increase observed in France in 2022 whereas it had virtually stopped being reported since the start of the COVID-19 pandemic in 2020.Methods. We analysed real-time PCR (qPCR) data from the two largest French outpatient laboratories performing whooping cough diagnosis and characterized all B. parapertussis isolates collected in the 2016-2022 period by the French National Reference Centre for Whooping Cough.Results. Microbiological analyses reveal that 13 of 18 bacterial isolates collected in 2022 produce the vaccine antigen pertactin, whereas none of the 22 isolates collected in the 2016-2021 period did.Conclusion. We hypothesize a re-introduction of B. parapertussis from regions of the world where whole-cell vaccines are still in use.

Objectives. Anti-fungal agents are increasingly becoming less effective due to the development of resistance. In addition, it is difficult to treat Candida organisms that form biofilms due to a lack of ability of drugs to penetrate the biofilms. We are attempting to assess the effect of a new therapeutic agent, N-acetylcysteine (NAC), on adhesion and biofilm formation in Candida parapsilosis clinical strains. Meanwhile, to detect the transcription level changes of adhesion and biofilm formation-associated genes (CpALS6, CpALS7, CpEFG1 and CpBCR1) when administrated with NAC in C. parapsilosis strains, furthermore, to explore the mechanism of drug interference on biofilms.Hypothesis/Gap statement. N-acetylcysteine (NAC) exhibits certain inhibitory effects on adhesion and biofilm formation in C. parapsilosis clinical strains from CRBSIs through: (1) down-regulating the expression of the CpEFG1 gene, making it a highly potential candidate for the treatment of C. parapsilosis catheter-related bloodstream infections (CRBSIs), (2) regulating the metabolism and biofilm -forming factors of cell structure.Methods. To determine whether non-antifungal agents can exhibit inhibitory effects on adhesion, amounts of total biofilm formation and metabolic activities of C. parapsilosis isolates from candidemia patients, NAC was added to the yeast suspensions at different concentrations, respectively. Reverse transcription was used to detect the transcriptional levels of adhesion-related genes (CpALS6 and CpALS7) and biofilm formation-related factors (CpEFG1 and CpBCR1) in the BCR1 knockout strain, CP7 and CP5 clinical strains in the presence of NAC. To further explore the mechanism of NAC on the biofilms of C. parapsilosis, RNA sequencing was used to calculate gene expression, comparing the differences among samples. Gene Ontology (GO) enrichment analysis helps to illustrate the difference between two particular samples on functional levels.Results. A high concentration of NAC reduces the total amount of biofilm formation in C. parapsilosis. Following co-incubation with NAC, the expression of CpEFG1 in both CP7 and CP5 clinical strains decreased, while there were no significant changes in the transcriptional levels of CpBCR1 compared with the untreated strain. GO enrichment analysis showed that the metabolism and biofilm-forming factors of cell structure were all regulated after NAC intervention.Conclusions. The non-antifungal agent NAC exhibits certain inhibitory effects on clinical isolate biofilm formation by down-regulating the expression of the CpEFG1 gene, making it a highly potential candidate for the treatment of C. parapsilosis catheter-related bloodstream infections.

Introduction. Ross River virus (RRV) is a mosquito-borne virus prevalent in Australia and the islands of the South Pacific, where it causes an arthritogenic illness with a hallmark feature of severe joint pain. The joint space is a unique microenvironment that contains cartilage and synovial fluid. Chondrocytes and synoviocytes are crucial components of the joint space and are known targets of RRV infection.Hypothesis/Gap statement. Understanding the relationship between synoviocytes and chondrocytes during RRV infection will provide further insights into RRV-induced joint pathology.Methodology. To better understand the unique dynamics of these cells during RRV infection, we used primary chondrocytes cultured in physiologically relevant micromasses. We then directly infected micromass chondrocytes or infected primary fibroblast-like synoviocytes (FLS), co-cultured with micromass chondrocytes. Micromass cultures and supernatants were collected and analysed for viral load with a PCR array of target genes known to play a role in arthritis.Results. We show that RRV through direct or secondary infection in micromass chondrocytes modulates the expression of cellular factors that likely contribute to joint inflammation and disease pathology, as well as symptoms such as pain. More importantly, while we show that RRV can infect micromass-cultured chondrocytes via FLS infection, FLS themselves affect the regulation of cellular genes known to contribute to arthritis.Conclusion. Single-cell culture systems lack the complexity of in vivo systems, and understanding the interaction between cell populations is crucial for deciphering disease pathology, including for the development of effective therapeutic strategies.

The application of a One Health approach recognizes that human health, animal health, plant health and ecosystem health are intrinsically connected. Tackling complex challenges associated with foodborne zoonoses, antimicrobial resistance, and emerging threats is imperative. Therefore, the One Health European Joint Programme was established within the European Union research programme Horizon 2020. The One Health European Joint Programme activities were based on the development and harmonization of a One Health science-based framework in the European Union (EU) and involved public health, animal health and food safety institutes from almost all EU Member States, the UK and Norway, thus strengthening the cooperation between public, medical and veterinary organizations in Europe. Activities including 24 joint research projects, 6 joint integrative projects and 17 PhD projects, and a multicountry simulation exercise facilitated harmonization of laboratory methods and surveillance, and improved tools for risk assessment. The provision of sustainable solutions is integral to a One Health approach. To ensure the legacy of the work of the One Health European Joint Programme, focus was on strategic communication and dissemination of the outputs and engagement of stakeholders at the national, European and international levels.

Introduction. The development of new antifungal drugs has become a global priority, given the increasing cases of fungal diseases together with the rising resistance to available antifungal drugs. In this scenario, drug repositioning has emerged as an alternative for such development, with advantages such as reduced research time and costs.Gap statement. Propafenone is an antiarrhythmic drug whose antifungal activity is poorly described, being a good candidate for further study.Aim. This study aims to evaluate propafenone activity against different species of Candida spp. to evaluate its combination with standard antifungals, as well as its possible action mechanism.Methodology. To this end, we carried out tests against strains of Candida albicans, Candida auris, Candida parapsilosis, Candida tropicalis, Candida glabrata and Candida krusei based on the evaluation of the MIC, minimum fungicidal concentration and tolerance level, along with checkerboard and flow cytometry tests with clinical strains and cell structure analysis by scanning electron microscopy (SEM).Results. The results showed that propafenone has a 50% MIC ranging from 32 to 256 µg ml^-1, with fungicidal activity and positive interactions with itraconazole in 83.3% of the strains evaluated. The effects of the treatments observed by SEM were extensive damage to the cell structure, while flow cytometry revealed the apoptotic potential of propafenone against Candida spp.Conclusion. Taken together, these results indicate that propafenone has the potential for repositioning as an antifungal drug.