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Phenotypic and genetic diversity is found in varying prevalence in clinical populations where beneficial adaptations enable the bacteria to avoid recognition and eradication by the host immune system. This study aimed to investigate the presence of Pseudomonas aeruginosa in chronic venous leg ulcers wounds over an 8-week time course. This was performed using genomic and phenotypic approaches to understand the survival and persistence of Pseudomonas strains. The findings of this study show that the two patients were colonized with a recurring P. aeruginosa genotype with only minor phenotypic differences and few SNP differences, suggesting that the Pseudomonas isolates present in the wound can survive and proliferate in the host's hostile environment. The results provided from this study will allow us to understand P. aeruginosa colonization during a 8 week time period., Competing Interests: All Authors have no competing interests to declare, (© 2025 The Author(s).)

Fritz Kauffmann (1899-1978) was a German/Danish microbiologist, who worked most of his years studying intestinal bacteria at Statens Serum Institut in Denmark. During his research, he implemented several diagnostic tools, which are still used in reference laboratories worldwide. Kauffmann was probably most known for developing the "Kauffmann-White scheme" based on the O- and flagella antigens on the surface of Salmonella. He was a visionary in his field, working at the intersection of microbiology and public health, as his research enabled proper diagnosis and tracking of diseases around the world., (© 2024 The Author(s). APMIS published by John Wiley & Sons Ltd on behalf of Scandinavian Societies for Pathology, Medical Microbiology and Immunology.)

Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic human pathogen, causing serious chronic infections. P. aeruginosa can adapt efficiently to antibiotic stressors via different genotypic or phenotypic strategies such as resistance and tolerance. The adaptation regulatory system is not always very well understood. In this study, we use shotgun proteomics to investigate the system-level response to tobramycin in two clinical wound P. aeruginosa isolates and PAO1. We profiled each strain for its antibiotic drug-tolerant phenotype using supra-minimum inhibitory concentrations (supra-MICs) of tobramycin and applied proteomics to investigate the protein expression profiles. The MIC revealed that all isolates were susceptible to tobramycin but at supra-MICs at stationary growth, a degree of tolerance was observed for the isolates. We identified around 40% of the total proteins encoded by the P. aeruginosa genome and highlighted shared and unique protein signatures for all isolates. Comparative proteome profiling in the absence of antibiotic treatment showed divergent fingerprints, despite similarities in the growth behavior of the isolates. In the presence of tobramycin, the isolates shared a common response in the downregulation of proteins involved in the two-component system, whereas stress response proteins were present at higher levels. Our findings provide insight into the use of proteomic tools to dissect the system-level response in clinical isolates in the absence and presence of antibiotic stress., Competing Interests: Conflict of interest The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: Borrelia burgdorferi sensu lato (Bbsl) and tick-borne encephalitis virus (TBEV) are tick-borne pathogens. This study aimed to investigate the seroprevalence of these pathogens in Danish blood donors., Methods: A total of 1000 plasma samples equally distributed (n = 200) from all five Danish regions were analyzed. Commercially available enzyme-linked immunosorbent assays were used to screen the samples for immunoglobulin G antibodies against Bbsl and TBEV. The samples positive for antibodies against TBEV were further examined with a commercially available enzyme-linked immunosorbent assay and a Luminex-based TBEV suspension multiplex immunoassay for specific antibodies against non-structural protein 1 (NS1) antigen suggestive of previous infection., Results: A total of 62 samples tested positive for immunoglobulin G antibodies against Bbsl. A total of 40 samples were positive or borderline for antibodies against TBEV, indicating potential infection or vaccination. Of these, one had antibodies against NS1, indicating past infection. The seroprevalence of Bbsl was 6.2% (95% confidence interval 4.8-7.8), with equal seroprevalence in all five regions. The seroprevalence of TBEV was 0.1% (95% confidence interval 0.01-0.62%)., Conclusions: The seroprevalence of Bbsl was similar throughout the country and corresponds well with previous studies. The seroprevalence of TBEV NS1 was low, which is in line with a low number of reported tick-borne encephalitis cases in Denmark. The NS1 positive sample was from the Capital Region, an endemic TBEV area., Competing Interests: None of the authors declare they have any financial conflicts of interests. Outside the present work, AML discloses speaker honoraria and advisory board activities from Gilead, ViiV/GSK, and Pfizer and a grant from The Lundbeck Foundation (R366-2021-127). The funding bodies had no role in writing the manuscript., (© 2024 The Author(s).)

An in-depth analysis of antibody epitopes following vaccination with different regimens provides important insight for developing future vaccine strategies. B-cell epitopes conserved across virus variants may be ideal targets for vaccine-induced antibodies and therapeutic drugs. However, challenges lie in identifying these key antigenic regions, and directing the immune system to target them. We previously evaluated the immunogenicity of two candidate DNA vaccines encoding the unmodified spike protein of either the SARS-CoV-2 Index strain or the Beta variant of concern (VOC). As a follow-on study, we characterized here the antibody binding profiles of three groups of mice immunized with either the DNA vaccine encoding the SARS-CoV-2 Index strain spike protein only, the Beta VOC spike protein only, or a combination of both as an antigen-heterologous prime-boost regimen. The latter induced an antibody response targeting overlapping regions that were observed for the individual vaccines but with additional high levels of antibody directed against epitopes in the SD2 region and the HR2 region. These heterologous-vaccinated animals displayed improved neutralization breadth. We believe that a broad-focused vaccine regimen increases neutralization breadth, and that the in-depth analysis of B-cell epitope targeting used in this study can be applied in future vaccine research.

Probiotics have been described to influence host health and prevent the risk of obesity by gut microbiome (GM) modulation. In a randomized double-blinded placebo-controlled feasibility study, we investigated whether Vivomixx® multi-strain probiotics administered to 50 women with obesity during pregnancy altered the GM composition and perinatal health outcomes of their infants up to 9 months after birth. The mothers and infants were followed up with four visits after birth: at 3 d, and at 3, 6, and 9 months after delivery. The infants were monitored by anthropometric measurements, fecal sample analysis, and questionnaires regarding health and diet.The study setup after birth was feasible, and the women and infants were willing to participate in additional study visits and collection of fecal samples during the 9-month follow-up. In total, 47 newborns were included for microbiome analysis.Maternal prenatal Vivomixx® administration did not alter infant GM diversity nor differential abundance, and the probiotic strains were not vertically transferred. However, the infant GM exhibited a decreased prevalence of the obesity-associated genera, Collinsella , in the probiotic group and of the metabolic health-associated Akkermansia in the placebo group, indicating that indirect community-scale effects of Vivomixx® on the GM of the mothers could be transferred to the infant.Moreover, 3 d after birth, the GM of the infant was influenced by mode of delivery and antibiotics administered during birth. Vaginally delivered infants had increased diversity and relative abundance of the metabolic health-associated Bifidobacterium and Bacteroides while having a decreased relative abundance of Enterococcus compared with infants delivered by cesarean section. Maternal antibiotic administration during birth resulted in a decreased relative abundance of Bifidobacterium in the GM of the infants. In conclusion, this study observed potential effects on obesity-associated infant GM after maternal probiotic supplementation.

Objectives: Lyme borreliosis (LB) is the most common tick-transmitted infection in the northern hemisphere and is caused by bacteria in the Borrelia burgdorferi sensu lato (Bbsl)-complex. The diagnosis is partially based on serology, and clinicians often take follow-up serum samples to look for seroconversion or an increase in IgG-antibody levels. In this registry-based study, we proposed a method for determining actual changes in IgG and examined antibody reactivity and decay., Methods: Serological data from the departments of clinical microbiology at Karlstad Hospital, Sweden, and Slagelse Hospital, Denmark, were used to calculate a seroreactivity cut-off (SCOFF), above which changes between two samples from the patient cannot be explained by random variation. Increases in IgG reactivity as well as IgG and IgM decay were illustrated using time-to-event analysis and the SCOFF., Results: A total of 44,861 serum samples from 34,157 patients were tested for Bbsl-antibodies. Of the 4301 patients with follow-up samples taken within 100 days, 201 (4.67%) were above the SCOFF of 1.42 with a median time to follow-up sample of 36 days (interquartile range: 21). IgG demonstrated longer median time for all antibody levels (indeterminate: 4.6 years, low: 7.0 years, moderate-high: 8.8 years) than IgM antibodies (indeterminate: 2.1 years, low: 3.9 years, moderate-high: 6.8 years) and higher initial antibody levels persisted significantly longer for both IgG and IgM antibodies (p < 0.001). Of the 7868 patients with follow-up samples, isolated IgM reactivity preceded an increase in IgG reactivity in 18 patients (0.23%)., Discussion: The SCOFF indicated little biological and random variation for Bbsl-specific IgG antibodies on the platforms used during the study. In most follow-up samples, both IgG and IgM antibodies persisted for years, with longer seropositivity associated with high initial antibody levels and IgG-type antibodies. The diagnostic value of isolated IgM reactivity was limited., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The ideal vaccine against viral infections should elicit antibody responses that protect against divergent strains. Designing broadly protective vaccines against SARS-CoV-2 and other divergent viruses requires insight into the specific targets of cross-protective antibodies on the viral surface protein(s). However, unlike therapeutic monoclonal antibodies, the B-cell epitopes of vaccine-induced polyclonal antibody responses remain poorly defined. Here we show that, through the combination of neutralizing antibody functional responses with B-cell epitope mapping, it is possible to identify unique antibody targets associated with neutralization breadth. The polyclonal antibody profiles of SARS-CoV-2 index-strain-vaccinated rabbits that demonstrated a low, intermediate, or high neutralization efficiency of different SARS-CoV-2 variants of concern (VOCs) were distinctly different. Animals with an intermediate and high cross-neutralization of VOCs targeted fewer antigenic sites on the spike protein and targeted one particular epitope, subdomain 1 (SD1), situated outside the receptor binding domain (RBD). Our results indicate that a targeted functional antibody response and an additional focus on non-RBD epitopes could be effective for broad protection against different SARS-CoV-2 variants. We anticipate that the approach taken in this study can be applied to other viral vaccines for identifying future epitopes that confer cross-neutralizing antibody responses, and that our findings will inform a rational vaccine design for SARS-CoV-2.

Background: The tick-borne bacterium, Neoehrlichia mikurensis (N. mikurensis) can cause severe febrile illness and thromboembolic complications in immunocompromised individuals. We investigated the presence of N. mikurensis DNA in retrospectively collected plasma from a well-characterized cohort of Danish immunocompromised patients., Methods: Plasma samples from 239 patients with immune dysfunction related to hematological or rheumatological disease or due to immunosuppressive therapy, were retrieved from a transdisciplinary biobank (PERSIMUNE) at Rigshospitalet, Copenhagen, Denmark. Serving as immunocompetent controls, plasma samples from 192 blood donors were included. All samples were collected between 2015 and 2019. Real-time PCR targeting the groEL gene was used to detect N. mikurensis DNA. Sequencing was used for confirmation. Borrelia burgdorferi sensu lato IgG antibodies were detected by ELISA as a proxy of tick exposure. Prevalence was compared using Fisher's exact test., Results: Neoehrlichia mikurensis DNA was detected in 3/239 (1.3%, 95% confidence interval (CI): 0.3 - 3.6%) patients, all of whom primarily had a hematological disease. Follow-up samples of these patients were negative. N. mikurensis DNA was not detected in any of the blood donor samples. IgG antibodies against B. burgdorferi s.l. were detected with similar prevalence in immunocompromised patients and blood donors, i.e., 18/239 (7.5%, 95% CI: 4.8-11.5%) and 11/192 (5.7%, 95%: CI 3.2-10.0%)., Conclusion: In this study, patients with N. mikurensis were not identified by clinical indication and N. mikurensis may therefore be underdiagnosed in Danish patients. Further investigations are needed to explore the clinical significance and implications of this infection., (© 2023. The Author(s).)

Reactive case detection (RACD) is the screening of household members and neighbors of index cases reported in passive surveillance. This strategy seeks asymptomatic infections and provides treatment to break transmission without testing or treating the entire population. This review discusses and highlights RACD as a recommended strategy for the detection and elimination of asymptomatic malaria as it pertains in different countries. Relevant studies published between January 2010 and September 2022 were identified mainly through PubMed and Google Scholar. Search terms included "malaria and reactive case detection", "contact tracing", "focal screening", "case investigation", "focal screen and treat". MedCalc Software was used for data analysis, and the findings from the pooled studies were analyzed using a fixed-effect model. Summary outcomes were then presented using forest plots and tables. Fifty-four (54) studies were systematically reviewed. Of these studies, 7 met the eligibility criteria based on risk of malaria infection in individuals living with an index case < 5 years old, 13 met the eligibility criteria based on risk of malaria infection in an index case household member compared with a neighbor of an index case, and 29 met the eligibility criteria based on risk of malaria infection in individuals living with index cases, and were included in the meta-analysis. Individuals living in index case households with an average risk of 2.576 (2.540-2.612) were more at risk of malaria infection and showed pooled results of high variation heterogeneity chi-square = 235.600, ( p < 0.0001) I 2 = 98.88 [97.87-99.89]. The pooled results showed that neighbors of index cases were 0.352 [0.301-0.412] times more likely to have a malaria infection relative to index case household members, and this result was statistically significant ( p < 0.001). The identification and treatment of infectious reservoirs is critical to successful malaria elimination. Evidence to support the clustering of infections in neighborhoods, which necessitates the inclusion of neighboring households as part of the RACD strategy, was presented in this review.

Leptospirosis is a zoonotic bacterial infection that can cause influenza-like symptoms and severe disease. In Denmark, leptospirosis is rare, non-endemic, and most commonly transferred to humans from mice and rats. Cases of human leptospirosis in Denmark are by law notifiable to Statens Serum Institut. This study aimed to describe trends in incidence of leptospirosis in Denmark from 2012 to 2021. Descriptive analyses were used to calculate the incidence, geographical distribution and possible routes of infection, as well as testing capacity and serological trends. The overall incidence rate was 0.23 per 100,000 inhabitants, with the highest annual incidence of 24 cases in 2017. Men between 40-49 years old were the demographic group most commonly diagnosed with leptospirosis. August and September were the months with highest incidence over the entire study period. The most common serovar observed was Icterohaemorrhagiae, although over a third of cases were diagnosed via polymerase chain reaction alone. The most common sources of exposure reported were travel abroad, farming, and recreational contact with fresh water, the latter being a new exposure compared to previous studies. Overall, a One Health approach would ensure better detection of outbreaks and milder disease. Additionally, preventative measures should be expanded to include recreational water sports., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Eves, Kjelsø, Benedetti, Jørgensen and Krogfelt.)

Competing Interests: RBD has received support for attending ECCMID in 2019 and 2018, participation in an Advisory Board Meeting Roche diagnostics 2018, Member of the executive committee of ESGBOR (www.escmid.org/esgbor) 2011-2019. LFO has received research grants from Region Värmland, Sweden. KAK has no conflicts of interest to disclose.

Background: Ulcerative colitis (UC) is a relapsing nontransmural inflammatory disease that is restricted to the colon and is characterized by flare-ups of bloody diarrhea. In this study, we aimed to investigate intestinal bacterial diversity in healthy controls and patients with UC with and without active disease, from Ghana and Denmark., Methods: The study included 18 UC patients (9 with active and 9 with inactive disease) and 18 healthy controls from Ghana. In addition 16 UC patients from Denmark (8 UC with active and 8 UC with inactive disease) and 19 healthy controls from Denmark. Microbiota diversity analysis relied on sequencing of ribosomal small subunit genes. Purified genomic DNA was submitted to PCR using a primer set targeting prokaryotes and eukaryotes. The purified DNA was sequenced on the Illumina MiSeq system in a 2 × 250 bp set up (Illumina, San Diego, CA, USA). Blinded analysis of the taxonomy table was performed using BioNumerics-7.5 (Applied Maths NV, Sint-Martens-Latem, Belgium)., Results: When analyzing the taxonomy data for prokaryotes, cluster and principal component analysis shows Danish healthy controls clustered together, but separate from healthy controls from Ghana, which also clustered together. The Shannon diversity index (SDI) for prokaryotes shows significant differences between Danish healthy controls and patients in comparison with the corresponding groups from Ghana ( p = 0.0056). Significant increased abundance of Escherichia coli was detected in healthy controls from Ghana in comparison with healthy controls from Denmark. The SDI of the prokaryotes ranges between 0 and 3.1 in the Ghana study groups, while in the Danish study groups it ranges between 1.4 and 3.2, the difference is however not significant ( p = 0.138). Our data show a significant increased abundance of eukaryotes species in the healthy control group from Ghana and Denmark in comparison with patient groups from Ghana and Denmark., Conclusion: Overall, healthy controls and patients with UC from Denmark have increased diversity of prokaryotes. Healthy controls from Denmark and Ghana have increased abundance of eukaryotes in comparison with UC patient groups from Denmark and Ghana., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Mirsepasi-Lauridsen, Vranckx, Nielsen, Andersen, Archampong, Krogfelt and Petersen.)

Introduction. Acute otitis media (AOM) is the most common bacterial infection in early childhood, but the underlying mechanisms making some children more susceptible are poorly understood. Aim. To examine the associations between bacterial airway colonization in early life and the risk of AOM and tympanostomy tube insertion (TTI), and whether such associations are modulated by an insufficient local immune mediator response to bacterial colonization. Methodology. Bacterial cultures from hypopharyngeal samples were obtained at 1 week, 1 month and 3 months of age in the Copenhagen Prospective Studies on Asthma in Childhood 2010 (COPSAC 2010 ) cohort comprising 700 children. Twenty immune mediators were quantified from airway mucosal lining fluid sampled at 1 month. AOM symptoms were registered in a daily diary until 3 years. Information on TTI in the first 3 years was obtained from national registers. Results. Children colonized with Streptococcus pneumoniae at 1 month of age had increased incidence of AOM [aIRR 2.43 (1.14-5.21)] and children colonized with Moraxella catarrhalis at 1 month or Haemophilus influenzae at 3 months had an increased risk of TTI [aHR 1.45 (1.00-2.10) and 1.73 (1.10-2.71)]. There were no associations between the local immune mediator response to colonization and risk of AOM or TTI. Conclusion. Pathogenic bacterial airway colonization in early life was found to be associated with an increased risk of otitis media, albeit not consistently. These associations were independent of the local immune response to colonization.

Rickettsia spp. can be found across the globe and cause disease of varying clinical severity, ranging from life-threatening infections with widespread vasculitis to milder, more localized presentations. Vector and, to some degree, reservoir are hematophagous arthropods, with most species harboured by ticks. In Denmark, rickettsiae are known as a cause of imported travel-related infections, but are also found endemically in ticks across the country. Data are, however, lacking on the geographical origin and clinical features of diagnosed cases. In this study, we have examined the travel history and clinical features of two groups of patients; 1) hospital-patients diagnosed with rickettsioses in the years 2010-2015 and 2) patients from primary health care (PHC) centers in Denmark having demonstrated anti-rickettsia antibodies in the years 2012-2015. The patients were identified using the Danish National Patient Registry (DNPR) and through the serological database at the State Serum Institute, where the laboratory diagnosis of rickettsioses is currently centralized. Data were collected for 86 hospital patients and 26 PHC center patients by reviewing hospital medical records and performing telephone interviews with PHC centers. Of the hospital patients, 91% (78/86) had a history of international travel 14 days prior to symptom start, with most having imported their infection from southern Africa, South Africa in particular (65%), and presenting with a clinical picture most compatible with African tick-bite fever caused by R. africae. Only two patients presented with a CRP > 100 mg/L and no mortalities were reported. At the PHC centers, most patients presented with mild flu-like symptoms and had an unknown (50%) or no history (19%) of international travel, raising the possibility of endemic rickettsioses. In view of our findings, rickettsioses do not appear to constitute a major public health problem in Denmark, with most cases being imported infections and potential endemic cases presenting as mild infections., (Copyright © 2018 The Authors. Published by Elsevier GmbH.. All rights reserved.)

Background: currently only 4 studies have explored the potential role of PARK7's dysregulation in MS pathophysiology Currently, no study has evaluated the potential role of the PARK7 interactome in MS., Objective: The aim of our study was to assess the differential expression of PARK7 mRNA in peripheral blood mononuclears (PBMCs) donated from MS versus healthy patients using data mining techniques., Methods: The PARK7 interactome data from the GDS3920 profile were scrutinized for differentially expressed genes (DEGs); Gene Enrichment Analysis (GEA) was used to detect significantly enriched biological functions., Results: 27 differentially expressed genes in the MS dataset were detected; 12 of these (NDUFA4, UBA2, TDP2, NPM1, NDUFS3, SUMO1, PIAS2, KIAA0101, RBBP4, NONO, RBBP7 AND HSPA4) are reported for the first time in MS. Stepwise Linear Discriminant Function Analysis constructed a predictive model (Wilk's λ = 0.176, χ 2 = 45.204, p = 1.5275e -10 ) with 2 variables (TIDP2, RBBP4) that achieved 96.6% accuracy when discriminating between patients and controls. Gene Enrichment Analysis revealed that induction and regulation of programmed / intrinsic cell death represented the most salient Gene Ontology annotations. Cross-validation on systemic lupus erythematosus and ischemic stroke datasets revealed that these functions are unique to the MS dataset., Conclusions: Based on our results, novel potential target genes are revealed; these differentially expressed genes regulate epigenetic and apoptotic pathways that may further elucidate underlying mechanisms of autorreactivity in MS., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The castor bean tick, Ixodes ricinus, is common in woodlands in most of Denmark. Besides Borrelia burgdorferi, it can harbour a number of pathogenic microorganisms such as tick-borne encephalitis virus, Anaplasma phagocytophilum, Rickettsia helvetica, Francisella tularensis, Candidatus Neoehrlichia mikurensis, Bartonella spp., Borrelia miyamotoi and Babesia spp. These tick-borne infections should be a differential diagnostic consideration during the tick season in Denmark. We review the distribution, clinical manifestations, diagnosis and treatment of these microorganisms.

Culture independent methods are used widely in diagnostic laboratories for infectious disease Isolation of genomic DNA from clinical samples is the first and important step in the procedure. Several procedures for extracting DNA from faecal samples have been described, including different mechanical cell disruptors. To our knowledge, the use of TissueLyser as a mechanical disruptor on faecal samples before DNA extraction has not been previously described. The purpose of the study was to implement a method for preparing faecal samples for optimal DNA extraction. Thus, three different procedures for extracting DNA from human faeces were compared. This was done either by using the mechanical disrupter by Mini BeadBeater 8, or the TissueLyser both followed by DNA purification using QIAamp DNA stool MiniKit, in comparison with DNA extractions using QIAamp DNA stool MiniKit without any prior mechanical disruption, according to manufacturer's instructions. The obtained DNA from the three procedures was analysed by DGGE, and the number of bands was compared between each procedure. There was no significant difference between the numbers of bacterial bands obtained from DGGE when using a TissueLyser or Mini BeadBeater 8, so the two different mechanical cell disruptors can be used comparably when isolating bacterial DNA from faecal samples. The QIAamp DNA stool MiniKit alone resulted in a reduced number of bands compared to the two mechanical disruption methods.

An enzyme-linked immunosorbent assay (ELISA) was adapted to measure immunoglobulin G (IgG), IgM, and IgA classes of human serum antibody to Campylobacter jejuni and Campylobacter coli. A total of 631 sera from 210 patients with verified Campylobacter enteritis were examined at various intervals after infection, and a control group of 164 sera were tested to determine the cut-off for negative results. With 90 percentile specificity, IgG, IgM, and IgA showed a sensitivity of 71, 60, and 80%, respectively. By combining all three antibody classes, the sensitivity was 92% within 35 days after infection, whereas within 90 days after infection, a combined sensitivity of 90% was found (IgG 68%, IgM 52%, and IgA 76%). Furthermore, we showed that 16% of the patients developed rheumatological symptoms after their Campylobacter gastrointestinal infection. We conclude that measurement of Campylobacter antibodies is a useful diagnostic tool to determine Campylobacter infections preceeding Guillain-Barré syndrome and for the investigation of post-enteritis reactive arthritis.