Non-ventilator hospital-acquired pneumonia (NV-HAP) is among the most prevalent health-care-associated infections, yet remains under-reported, understudied, and infrequently targeted by infection prevention strategies. Oral care is considered a key preventive measure; however, there are few high-quality randomised controlled trials conducted in hospital settings. The aim of this study is to evaluate whether an enhanced oral care intervention reduces the incidence of NV-HAP. The Hospital Acquired Pneumonia Prevention (HAPPEN) trial was an open-cohort, stepped-wedge, cluster-randomised trial conducted across three Australian hospitals. Large public or private hospitals were eligible. Simple randomisation was used to allocate nine wards (clusters) across three treatment sequences. All patients aged 18 years or older admitted to a trial cluster were eligible, with outcomes assessed for patients admitted for at least 48 h. The intervention comprised three components: enhanced delivery of oral care and provision of products, patient and staff education, and audit and feedback, delivered by dedicated research nurses. The control was usual practice-ie, oral care performed by health-care workers as per hospital policy. Primary and secondary outcomes were analysed in the intention-to-treat population. The primary outcome was NV-HAP incidence, defined according to European Centre for Disease Prevention and Control criteria. Secondary outcomes included hospital-acquired lower and upper respiratory tract infections and oral cavity infections. Outcomes were defined using established definitions and determined following a review of medical records. This study was single blinded, with data collectors masked to allocated treatment sequences. The completed trial is registered with the Australia New Zealand Clinical Trials Registry (ACTRN12624000187549). The trial was conducted from June 3, 2024, to Aug 22, 2025. A total of 12 446 admitted patients were eligible to receive the intervention, 3336 of whom were excluded because they were admitted to a trial cluster for less than 48 h. A total of 8870 patients were analysed, with 4523 exposed to the control condition and 4347 exposed to the intervention condition. NV-HAP was confirmed in 78 (0·9%) of 8870 patients: 46 (1·0%) of 4523 under the control condition and 32 (0·7%) of 4347 under the intervention condition. Intervention exposure was associated with a cumulative hazard ratio of 0·40 (95% CI 0·19-0·82), representing a decrease from 1·00 to 0·41 infections per 100 admission-days at risk. Intervention exposure resulted in a cumulative hazard ratio of 1·64 (95% CI 0·61-4·39) for lower or upper respiratory tract infection, and 1·08 (0·66-1·77) for oral cavity infection. The proportion of participants who completed the oral care protocol increased from 474 (15·9%) of 2988 to 1727 (61·9%) of 2791 following intervention exposure. This multicentre randomised controlled trial demonstrates that improving oral care reduces NV-HAP incidence among hospitalised patients, compared with usual care. Our findings provide novel and clinically important evidence to inform future prevention guidelines and hospital infection control policy. Medical Research Future Fund.
Hookworms infect nearly half a billion people, causing approximately 2.1 million disability-adjusted life-years lost. While anthelmintic drugs are available, they do not prevent reinfection. A vaccine could provide long-term immunity, but none currently exist. We recently demonstrated that human subjects can be safely vaccinated with irradiated hookworm larvae, eliciting humoral and cellular immune responses that induce partial protection against challenge infection with non-irradiated parasites. Using immunomic approaches, we identified IgG targets in vaccinated individuals by screening a proteome microarray containing recombinant proteins sourced from the secretome of Necator americanus. We characterized the most immunoreactive N. americanus proteins and identified their orthologs in the rodent hookworm Nippostrongylus brasiliensis. These N. brasiliensis proteins were expressed recombinantly and tested for efficacy in a mouse challenge model. Our lead vaccine candidate NBR17057 - a homolog of Na_11335 provided robust protection against infection, evidenced by >90% reductions in intestinal worm burden and fecal egg counts, and elevated antigen-specific IgG levels. Vaccination also stimulated IgA+ B-cells, IgG1+/IgA+ plasma cells, and IgG1+/IgA+ germinal centre B-cells in inguinal lymph nodes, indicating gut immunity. Additionally, high levels of IgG1+/IgA+ B-cells, germinal centre B-cells, and plasma cells in the spleen suggest protection against systemic larval migration. The presence of IgG1+/IgA+ memory B-cells in both the lymph nodes and spleen indicates potential long-term immunity against reinfection. Our findings suggest that a N. brasiliensis L3 larval-stage protein NBR17057 and its homolog in N. americanus Na_11335 could serve as a promising subunit vaccine candidate targeting the infective larval stage of human hookworms.
Neonatal sepsis causes substantial mortality. Topical antisepsis for laboring women or neonates may reduce pathogenic colonization and sepsis risk. To evaluate the safety and effectiveness of various topical antiseptic regimens to reduce bacterial load in the maternal genital tract and on neonatal skin and assess suitability for future effectiveness trials. This randomized clinical trial was conducted from March 7, 2022, to March 29, 2023, at Zomba Central Hospital, Malawi, with 28-day follow-up. Participant populations were laboring women and, separately, facility-born neonates (aged <24 hours and with birth weight >1000 g) not born to a mother recruited to the trial. Data were analyzed from May 17 to December 28, 2023. Participants were individually randomized in an unblinded factorial design to chlorhexidine 1% (1% CHG), chlorhexidine 2% (2% CHG), or octenidine 0.1% with phenoxyethanol 2% (OHP), each applied either once or multiple times (maternal: antiseptic applied every 4 hours during working hours for up to 6 applications; neonatal: antiseptic applied every 24 hours for up to 3 applications), or to standard of care (SOC; application of sterile water for mothers and no cleansing for neonates). Laboratory staff assessing primary outcomes were blinded. Co-primary outcomes were change in total skin bacterial load (log10 colony-forming units [log10CFU]) from baseline at each follow-up, analyzed separately in the maternal and neonatal populations and adjusted for intervention variables. Secondary outcomes included skin condition score (range, 0-12 for neonates and 0-16 for women; lower scores indicate better condition), serious adverse events (SAEs), and neonatal temperature. A total of 149 women (mean [SD] age at enrollment, 25.7 [5.9] years) and 147 neonates (mean [SD] age at enrollment, 10.3 [6.3] hours; 82 [56%] male) participated. Mean (SD) infant gestational age was 37.7 (1.5) weeks in the maternal population and 36.7 (3.1) weeks in the neonatal population. Neonates' mean birth weight was 2729 g (712 g). Among mothers, compared with 1% CHG, bacterial load was higher (worse) with OHP (adjusted log10CFU difference, 1.7; 95% CI, 0.9-2.5) and SOC (3.5; 95% CI, 2.4-4.6); there was no clear log10CFU difference with 2% CHG (-0.6; 95% CI, -1.4 to 0.2). There was no evidence of difference in effectiveness between multiple vs single application (log10CFU difference, -0.4; 95% CI, -1.1 to 0.2). In neonates, 1% CHG showed greater effectiveness than SOC (log10CFU difference, 1.3; 95% CI, 0.2-2.4) but no difference vs 2% CHG (-0.2; 95% CI, -1.1 to 0.7) or OHP (0.7; 95% CI, -0.2 to 1.6). Multiple applications showed increasing benefits over time (frequency × time interaction). Skin scores were low (almost all were 0-1 and none ≥3). There were no significant differences in SAE rates between arms and no signal of postantiseptic neonatal hypothermia. In this randomized clinical trial of topical antiseptics applied in laboring women and in neonates, 1% CHG reduced maternal and neonatal bacterial colonization without safety concerns, suggesting it would be the optimal regimen to evaluate in a larger pragmatic trial powered for clinical outcomes. ISRCTN Registry Identifier: ISRCTN78026255.
Bacteriophages (phages), viral predators of bacteria, are an attractive way to combat the rise of antimicrobial resistance. By infecting and killing bacteria, phages generate selection pressure for the evolution of defense systems. Successfully applying phages in the clinic will, in part, depend on understanding and predicting how bacterial defense systems determine the outcomes of a phage infection. Here, we present morphological, genomic, phylogenetic, and modification-based characterization of 12 new bacteriophage species targeting Escherichia coli, isolated from water sources in Durham, UK, during undergraduate practical classes. These phages, added to our growing "Durham Collection," were all determined to be sensitive to the GmrSD-family Type IV restriction enzyme, BrxU. As such, these phages have modified genomic DNAs. HPLC and MS analysis of the genomic DNAs identified a range of modifications present in the Tequatrovirus, Krischvirus, and Mosigvirus phages, the latter of which contained 5-arabinosyl-2'-deoxycytidine (5-ara-dC) and disaccharide arabinobiose (5-ara-ara-dC) moieties. Curiously, Krischvirus phages were shown to have modification pathways distinct from those of Tequatrovirus phages. Finally, testing the modified genomic DNAs in in vitro cleavage assays with BrxU demonstrated cleavage of all modifications tested. This further extends the broad substrate specificity previously identified for BrxU. Collectively, these data provide a larger standardized Durham Collection to be used for better prediction of phage-host interactions and infection outcomes.IMPORTANCEWidespread antibiotic use has led to rising rates of antibiotic resistance. It is estimated that deaths from antibiotic-resistant bacterial infections will outpace deaths from cancer by 2050. Alternate methods of treatment are required. Bacteriophages (phages), are viruses that specifically target bacteria and are predominantly harmless to humans. There is increased interest in using phage therapy in clinics to treat infections. Studying interactions between bacteria and phages is necessary so that we can understand and better predict the outcomes of phage therapy. This will increase the chances of clinical success. Our presented work provides detailed characterization of a set of phages isolated from the environment that infect Escherichia coli, a common pathogen and model experimental system. Standardized collections of phages are time-consuming to generate and the results from our ongoing characterization of the Durham Collection presented here represent a community resource for the ease of comparison between these and other phages strains, as well as across different experimental systems.
In the second half of 2022 and 2023, an increase of diphtheria cases among asylum seekers was observed in Europe, with 120 cases reported in the state of Baden-Wuerttemberg, Germany. We aimed to determine prevalence of infection or colonization with toxigenic Corynebacterium among asylum seekers arriving between August and October 2024 in Heidelberg, Germany. In addition, we assessed antimicrobial-resistant wound infections and diphtheria immunity levels in this population. We conducted a cross-sectional study with a random sample of 1073 newly arrived asylum seekers. Consenting participants received a throat and, if applicable, wound swabs. Demographic, clinical and migration-related information was collected to identify potential risk groups. Throat swabs were tested for toxigenic Corynebacterium species, while wound swabs were additionally tested for other antimicrobial-resistant pathogens with relevance to therapeutic management. IgG antibody levels against diphtheria toxoid were quantified in serum samples of a random sub-sample. Of the participants, 75% were male (n = 804), and ages ranged from 15 to 60 years (median = 27 years). The most common nationalities were Syrian (n = 281), Turkish (n = 189) and Afghan (n = 117). No toxigenic Corynebacterium was identified. Thirty-seven participants carried inflamed wounds, of whom 18 (49%) had wounds infected with methicillin-resistant Staphylococcus aureus (MRSA), corresponding to 1.7% (95% CI 1.0-2.6%) of the entire study population. Overall, 38.0% (95% CI 33.3-44.8%) showed non-protective diphtheria antibody titers, while acceptance of the on-site diphtheria vaccination was high at 93% (n = 998). While no toxigenic Corynebacterium was detected, low immunity levels and antimicrobial resistance findings underline the importance of early diagnosis, treatment and vaccination options in displaced populations.
Background/Objectives: Immunodeficiency can be induced by a variety of factors, such as aging, stress and poor nutrition, and leads to increased susceptibility to infection and disease. The current research was conducted to determine the immunoenhancing potential of yam and its underlying mechanism in a murine model of cyclophosphamide (CTX)-induced immunosuppression. Methods: The gut microbial community and generation of short-chain fatty acids (SCFAs) in response to yam were analyzed by 16S rRNA sequencing and GC-MS. The immune cells in the spleen were analyzed using flow cytometry. GPR41/GPR43/GPR109A triple-knockout mice were used to demonstrate the critical involvement of SCFAs in mediating the protective effect of yam, and RNA-sequencing technology was applied to investigate the potential mechanism by which yam orchestrated the observed metabolic, immune and reparative responses. Results: Yam alleviated the decline in spleen and thymus indices and modulated the frequency of B cells and CD4+ and CD8+ T cells and promoted the production of IgA, IgG and IgM. Yam increased the secretion of cytokines in the intestine and upregulated the levels of claudin and ZO-1. Yam also increased the content of SCFAs and induced beneficial modifications to the gut microbiota composition. The immune-enhancing activity of yam was confirmed, as evidenced by a notable decrease in viral load in immunosuppressed mice inoculated with influenza virus and its capacity to mitigate inflammatory response in pulmonary tissues. Conclusions: This study suggests that yam enhances immunity by synergistically regulating the gut-immune axis, supporting its development as a functional food intervention in managing immunodeficiency conditions.
Helminth parasites infect over a quarter of the global population and can profoundly modulate host immunity, potentially influencing vaccine performance and the spread of pandemic pathogens such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite the high global endemicity of helminth infections, their impact on immune responses to various COVID-19 vaccines remains unknown. This study aimed to evaluate the impact of Schistosoma infection on the immunogenicity and protective efficacy of messenger RNA (mRNA)- and protein-based COVID-19 vaccines. Mice with Schistosoma infection and non-infected controls were immunized with either an mRNA-based COVID-19 vaccine or an alum-adjuvanted spike protein vaccine. Vaccine-induced humoral and cellular immune responses were assessed, and protective efficacy was evaluated using a SARS-CoV-2 challenge model. COVID-19 mRNA vaccination induced strong spike-specific antibody and CD4 T-cell responses in Schistosoma-infected mice comparable to non-infected controls, despite a Th2/regulatory-biased immune environment, although multifunctional CD8 T-cell responses were reduced. Alum-adjuvanted protein vaccination elicited robust humoral but weaker cellular immunity, with comparable immune responses in infected and non-infected mice. Following SARS-CoV-2 challenge, both vaccine platforms conferred effective protection, with substantial viral clearance and minimal lung pathology. mRNA and protein vaccines elicit distinct immune profiles; however, both protect effectively against SARS-CoV-2 infection in mice with concurrent helminth infection.
Staphylococcus aureus (S. aureus) is a highly virulent pathogen responsible for chronic infections such as osteomyelitis. Although its interaction with the host immune system has been widely studied, the specific role of inflammasomes in regulating the infection within macrophages remains unclear. We investigated this question using bone marrow-derived macrophages (BMDMs) infected with S. aureus for up to 96 hours (h). We observed a significant reduction in intracellular bacterial load beginning at 18 h post-infection (hpi), which continued through 96 hpi; this response was partially attenuated in BMDMs lacking NLRP3. Mechanistically, activation of the NLRP3 inflammasome, including ASC speck formation, IL-1β secretion, and pyroptosis, was modest and detectable only after 18 hpi. Consistent with these findings, infected BMDMs failed to respond robustly to NLRP3 inflammasome activators, lipopolysaccharide (LPS) and nigericin, up to 18 hpi, with only partial restoration of responsiveness at later time points. We also found that NLRP3 deficiency did not significantly affect bacterial burden control or bone homeostasis in experimental S. aureus osteomyelitis. Thus, S. aureus is inadequately controlled by the NLRP3 inflammasome in macrophages and within the bone microenvironment.IMPORTANCEStaphylococcus aureus causes difficult-to-treat, long-lasting infections such as osteomyelitis. While many aspects of how the immune system responds to this pathogen are known, it is still unclear how the inflammasomes contribute to controlling the infection inside macrophages. In this study, we found that macrophages gradually reduced the number of bacteria they contained over time, but this ability was only partly dependent on one major inflammasome component, NLRP3. Importantly, the inflammasome response to S. aureus was weak and delayed, becoming noticeable only well after infection had begun. Even when stimulated with agents that normally trigger a strong inflammasome response, infected macrophages responded poorly. Consistent with these findings, the absence of NLRP3 did not significantly worsen bacterial control or bone damage in a mouse model of osteomyelitis. Together, these results suggest that S. aureus largely evades inflammasome-based defenses, limiting their effectiveness in controlling infection in immune cells and bone.
Evolving endemic viruses such as influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remain major health threats. Although variant updated vaccines aim to enhance protection, preexisting immunity shapes memory B cell (MBC) responses. To assess how SARS-CoV-2 spike protein variant-based vaccine boosters and infections alter the MBC repertoire, we analyzed MBC responses in the COVAIL vaccine trial, where participants previously vaccinated with SARS-CoV-2 Wuhan-1 spike immunogen were boosted with Wuhan-1, variant, or bivalent spike immunogens. Some participants also experienced a subsequent infection with an Omicron variant. We determined that variant vaccine boosters and SARS-CoV-2 infections led to transiently greater recall of cross-reactive MBCs compared with a Wuhan-1 vaccine booster. Long term, we detected little change in the MBC repertoire after an Omicron vaccine booster, but MBCs evaluated several months after Omicron variant infection had higher neutralization capacity to both Wuhan-1 and BA.1 compared with those from individuals who had not experienced an infection. However, these Wuhan-1/BA.1 cross-reactive MBCs from infected individuals displayed less breadth toward the more distant BA.2.86 lineage than MBCs from uninfected individuals. Thus, SARS-CoV-2 variant boosters and infections differentially shape the long-term MBC repertoire.
Many Clostridioides difficile strains can form two colony morphotypes: rough and smooth. The rough and smooth morphotypes differ in multiple phenotypes, including cell length and chaining, motility, biofilm production, and virulence in the hamster model of C. difficile infection (CDI). Colony morphology undergoes phase variation and is determined by the ON/OFF expression of cmrRST, which encodes a signal transduction system. Here, we test the hypothesis that differences in colony morphology and the associated phenotypes influence pathogenesis and the host response to infection. We first compared the rough and smooth colony variants of wild-type C. difficile in a mouse model of CDI. However, CmrRST phase varied during infection such that the C. difficile populations became indistinguishable in feces and tissues, and no differences in disease were observed in mice inoculated with these variants. We next circumvented phase variation using mutants that form only rough or only smooth colonies. Co-infection of mice with these phenotypically locked strains revealed that the smooth colony mutant has greater fitness than the rough mutant, which is outcompeted during late infection. In addition, NanoString analyses showed a higher number of differentially expressed pro-inflammatory genes and overall higher expression levels in mice infected with the rough colony mutant, independent of bacterial burden and toxin levels. Our results indicate that in a mouse model of CDI, cells from rough colonies are more immunostimulatory during early murine infection, potentially leading to reduced relative fitness compared to cells from smooth colonies.
To explore healthcare professionals' perceptions and experiences with point-of-care testing (PoCT) implementation within Australia's healthcare system and identify potential strategies for effective governance and improvements to regulation and guidelines that facilitate coordinated integration of quality PoCT into healthcare systems. A descriptive qualitative study with thematic analysis with codes derived inductively from the transcriptions and a structured framework analysis using the six building blocks of the WHO Health Systems Framework exploring barriers and enablers to PoCT implementation. Healthcare settings in Australia. Healthcare workers with patient care responsibilities and healthcare administrators with oversight or regulatory responsibility for a service. 18 participants were interviewed with four from hospitals, four from primary care, three from community care, three from pathology laboratories, two from emergency care and two from pharmacy settings. Healthcare professionals' perspectives on PoCT implementation were grouped into three main themes: (1) community-centric pathology testing, (2) connectivity and continuity of care and (3) quality and governance. Participants identified insufficient health system financing and health information systems as significant barriers to PoCT implementation. Improved practical guidance for workforce training and health service delivery to interpret the current regulation outside of laboratory settings was viewed as a potential enabler to establishing PoCT within healthcare services. Participants reflected that Australia has several examples of successful PoCT programmes providing patient-centred pathology to improve healthcare equity. However, the lack of information systems, funding, workforce training and diagnostic strategies prohibits the implementation of PoCT at-scale. It was recommended that adequately financing PoCT to encompass costs for testing, quality management and workforce training would incentivise services to obtain accreditation and ensure quality healthcare delivery. Despite the potential of PoCT to improve equitable healthcare access and patient outcomes, health system strengthening is required to integrate PoCT effectively across Australian healthcare services.
To evaluate the association between immune status and subclinical myocardial injury by cardiovascular magnetic resonance (CMR) in people with HIV (PWH), independent of traditional cardiovascular risk factors. This prospective study enrolled 98 PWH without known cardiovascular disease (CVD) and 91 Framingham Risk Score (FRS)-matched non-HIV controls. Myocardial function and tissue characteristics were assessed by CMR, including native T1/T2 mapping, extracellular volume fraction (ECV), and late gadolinium enhancement (LGE). Immunologic and treatment-related variables included duration of HIV infection, duration of ART, HIV viral load, current and nadir CD4+ and CD8+ T-cell counts, and CD4/CD8 ratio. Linear and logistic regression analyses adjusted for FRS and heart rate evaluated associations between immunologic parameters and CMR findings. PWH demonstrated elevated global native T1, T2, ECV, and LGE, with reduced global longitudinal strain (GLS) and global circumferential strain (GCS) compared with non-HIV controls (all P < 0.05). In multivariate analysis, current CD4+ T-cell counts correlated negatively with global native T1 (β = -0.361, P < 0.001) and ECV (β = -0.318, P = 0.001). Current CD4+ cell count <200 cells/μl was independently associated with elevated native T1 [odds ratio (OR), 7.199; 95% confidence interval (CI), 1.373-37.746; P = 0.020] and elevated ECV (OR, 5.152; 95% CI, 1.260-21.062; P = 0.023). PWH exhibit subclinical myocardial fibrosis and dysfunction despite similar FRS to non-HIV controls. Current CD4+ T-cell counts <200 cells/μl is an independent predictor of subclinical myocardial injury.
Fungi have been a rich source of pharmaceuticals such as antibiotics, immunosuppressants, and cholesterol-lowering drugs; however, their therapeutic potential remains largely untapped due to difficulties in culturing and elucidating the genetic basis of beneficial traits. Fungi contain 'cryptic' genes that are expressed under certain, and often obscure, growth conditions and can produce complex compounds that are difficult to synthesize economically. Developments in genome sequencing and DNA-synthesis technologies offer new opportunities to produce such compounds using biotechnological techniques, however, accurately identifying useful and novel genes, a prerequisite for such approaches, remains challenging. We present a novel 'two-by-two' comparative genomics pipeline for comprehensive gene analysis of selected fungal groups, enabling more confident identification of unique genes across the analyzed species. The approach compares gene sets from two strains of the same species with those from two strains of different species or families within a fungal order. Self-clustering orthologs that are unique to strains from the same species provide higher confidence in identifying species-specific proteins and help reduce noise from low-quality genome assemblies and gene prediction errors. We validated our method in a well-studied fungal group, correctly identifying known species-specific genes and gene clusters, and discovering a novel functional myco-serpin and a fungal Tc toxin complex in Metarhizium. Elucidating the genes underlying beneficial traits in fungi presents significant challenges, largely due to the unique and relatively complex aspects of their lifestyles. The two-by-two approach shows broad potential for fungal genome mining and bioprospecting, demonstrated by our discovery of the first fungal Tc toxin complex and a functional myco-serpin in Metarhizium (Hypocreales), and is applicable to other fungal orders such as Eurotiales and Xylariales. Furthermore, the two-by-two approach can be adapted to other organisms with genome architectures similar to fungi.
Surveillance of arboviral vectors and screening for probable infection is very important for the planning of vector control programs, especially in countries where these activities are just beginning. In the present study, we conducted mosquito surveillance at 26 locations predicted to be at risk (according to our recently published study using Machine learning) in the Marrakech-Safi region of central Morocco. The field studies were conducted for six consecutive months, from April to October, in 2019 and 2021. Two different methods were used to collect adult mosquitoes, human landing catches (by mouth aspirator), and CDC miniature light traps; larvae and pupae were collected using dippers. A total of 1907 mosquitoes were collected, belonging to 15 species across five genera (Aedes, Culex, Culiseta, Anopheles, and Coquillettidia). Out of the 1907 mosquitoes that were sampled, 53.7% (1025/1907) were in the larval stage, 42.8% (818/1907) were adults, and the remaining 3.3% (64/1907) were pupae. Among the collected and identified adults, the females represented 96.6% and blood-fed females accounted for 55.9%. The adult mosquitoes were screened for five arboviruses: dengue virus (DENV), chikungunya virus (CHIKV), Zika virus (ZIKV), Rift Valley fever virus (RVFV), and West Nile virus (WNV) by using RT-qPCR, and a pool of Cx. pipiens from Tabia (Station 14) was positive for WNV. This is the first detection of WNV in Cx. pipiens or any other mosquito species from central Morocco. The detection of several vectors within the region suggests a risk for arboviral transmission in central Morocco and appeals for entomological vigilance and the urgent need to undertake and enhance periodic surveillance campaigns in the region.
Early childhood events, up to the age of two, are critical for the development of the microbiome and balanced immunity later in life. We investigated whether susceptibility to infections and microbiome resilience after antibiotic treatment are associated with key taxa in the early childhood microbiota. Therefore, we performed longitudinal microbiota analysis from stool samples of children within the German LoewenKIDS intensified subcohort. According to the exposure to antibiotic treatment, sample groups were defined as never-treated controls, 45-225 days pre-treatment (pre45-225), 0-30 days pre-treatment (pre0-30), 0-30 days post-treatment (post0-30), or >90 days post-treatment and age >540 days (post>90). 1176 stool samples of 162 children were included in our analysis, of which 49 children received antibiotics. Using generalized linear mixed models adjusted for age, we show that high abundance of Bacteroides was associated with receiving antibiotic treatment 45-225 days later, while low Bacteroides abundance before treatment was associated with low alpha diversity and increased beta diversity post treatment. Our data suggest a key role of the genus Bacteroides for the susceptibility to infections requiring antibiotic treatment and for microbiome stability and resilience in early childhood.
Immunity through nutrient sequestration is one of the means by which a host can protect itself from infection. As a consequence, many micro-organisms have evolved strategies to overcome this, including the opportunistic pathogen Staphylococcus aureus. In this study, we focussed on a population of SAB isolates with the aim of better understanding their ability to grow in a low-iron environment and observed a significant association between a weakened ability to grow in a low-iron environment and whether the entry point of the bacteria into the bloodstream was urogenital in origin. Follow-up experiments demonstrated that urine at 10% provided sufficient iron for both a defined iron uptake mutant (sbnE::Tn) and our iron-dependent clinical isolates to grow, in the absence of other sources of iron. This potentially explains their association with this environment where, although at relatively low levels, the iron there is such that those with poor iron utilization ability can survive. This does not however explain how these isolates went on to successfully cause bacteraemia, given how poorly available iron is in the bloodstream. To determine whether these iron-dependent isolates had some alternative means of surviving in blood, we exposed them to fresh human blood and found that although they had previously all successfully established an infection in the bloodstream, the iron-dependent isolates did not survive as well as the non-dependent isolates. This work highlights the complexity and apparent contradictory nature of the factors that contribute to the development of this important disease.
Hepatitis B virus (HBV) and hepatitis C virus (HCV) remain public health threats in the WHO European region, where an estimated 29 million people live with chronic infection and viral hepatitis-related deaths now surpass those from HIV/AIDS and tuberculosis combined. Although effective prevention tools and antiviral treatments reduce the risk of complications, overall mortality has not declined. This Series paper reviews models of care (MoC) implemented between 2015 and 2025, drawing on scientific literature and policy documents to assess regional progress. Simplified testing and treatment, childhood and targeted adult HBV vaccination, harm-reduction programmes, and prison-based interventions have advanced elimination efforts. Pragmatic approaches, including point-of-care testing, decentralised services, and integrated models tailored to key populations demonstrate clear benefits. However, major challenges persist: large undiagnosed populations, regional disparities, inadequate healthcare worker knowledge, and inequities affect at-risk groups. Achieving elimination by 2030 will require accelerated case-finding, broader access to simplified treatment, stronger risk-tailored and vaccination strategies, improved data systems, and renewed commitment.
The cytokines interleukin (IL)-22 and IL-17 are secreted by innate and adaptive immune cells to drive "type III" responses that protect against extracellular pathogens, promote mucosal barrier integrity, and foster microbiota homeostasis. However, dysregulation of IL-22 and/or IL-17 contributes to autoimmunity, chronic inflammation, and malignancy. Thus, a deeper understanding of mechanisms regulating type III cytokine production could provide new therapeutic targets for a spectrum of immune-mediated diseases. Toward this goal, we performed a genome-wide CRISPR inhibition (CRISPRi) screen to identify factors that regulate IL-22/IL-17 expression in a murine type III innate lymphoid cell (ILC3) model, MNK3, following stimulation with IL-23 and IL-1β. In addition to previously known regulators of type III cytokines, including IL-23 receptor components IL23R and IL12Rβ1, the screen identified a large set of new factors that either potentiate or attenuate expression of IL-22 and/or IL-17. A subset of these novel factors was chosen for validation, from which two were selected for further study. Knockdown of nuclear protein, SON, which binds both DNA and RNA, impaired expression of IL12Rβ1 at the levels of de novo transcription and RNA processing. The second, MAP4K1 (HPK1), is a serine/threonine kinase that is required for IL-22 but not IL-17 expression. Depletion of MAP4K1 in MNK3 also enhanced expression of the type I cytokine, IFN-γ, which was co-expressed with IL-17, a phenotype reminiscent of pathogenic Th17 cells. Together, results from the CRISPRi screen broaden our understanding of the factors involved in type III immune responses and offer new targets for modulating IL-22/17 expression.
Chlamydia trachomatis (Ct) is a causal agent of upper reproductive tract pathology. There is a broad spectrum of cervical Ct load in infected women, and upper tract infection is associated with higher cervical Ct load. Recent studies indicate that bacterial vaginosis (BV) can modulate host-Ct outcomes. To identify features associated with BV status and Ct load, we performed an integrated multi-omics analysis of the cervicovaginal microbiome, tryptophan metabolome, and cytokines. Samples were analyzed using 16S rRNA gene sequencing, targeted UPLC-MS/MS quantification of tryptophan metabolites, and multiplex cytokine profiling. Ordination analyses showed that BV status was separated by the microbiome, metabolome, and cytokines, whereas Ct load was separated only by cytokines. K-means clustering of tryptophan metabolites defined three metabolome state types (MSTs). MST I, associated primarily with Lactobacillus crispatus-dominated community state type (CST) I, exhibited high tryptophan availability, indole-3-lactic acid, and complete kynurenine-pathway activity. Both MST II and MST III were associated with BV-associated CST IV and showed marked tryptophan depletion. MST II was broadly depleted of most tryptophan metabolites, while MST III was enriched in downstream microbially derived indole pathway metabolites and kynurenic acid. Hierarchical all-against-all association testing revealed coordinated relationships linking clusters of bacterial taxa, metabolites, and cytokines. Importantly, multi-omics network analyses identified integrated microbial-metabolic-immune modules that predicted high versus low Ct load, highlighting CXCL9, CXCL10, IL-17, BV-associated taxa, and indole pathway metabolites as key discriminative features. Results demonstrate that cervical Ct load reflects coordinated microbial-metabolic-immune ecological states rather than microbiome composition alone and refine current models of Ct-BV interactions.
Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of severe, life-threatening infections worldwide, highlighting an urgent and unmet need for effective vaccines. Current Staphylococcus aureus (S. aureus) vaccine candidates predominantly employ aluminum-based adjuvants, which potently induce Th2-biased humoral immunity but fail to adequately elicit protective Th1/Th17 cellular responses. Given that Th1 and Th17 responses are critical for clearance of S. aureus infection, developing an adjuvant platform capable of redirecting immunity toward these pathways is urgently needed. To address this limitation, we aimed to develop a novel nano-vaccine and systematically evaluate its immunogenicity and protective efficacy. We constructed a nano-vaccine using PLGA15k-PEG5k-COOH nanoparticles (25%NPs) as the adjuvant and recombinant clumping factor A (rClfA) as the antigen. The immunogenicity of the 25%NPs-rClfA vaccine was compared with that of an aluminum-adjuvanted formulation. Specific antibody levels, neutralizing activity, and cytokine production (IFN-γ and IL-17A) were measured. Protective efficacy was assessed by challenging immunized subjects with a lethal dose of S. aureus strain ATCC25923. Mechanistic studies included evaluation of neutrophil phagocytosis and reactive oxygen species (ROS) release. The necessity of the Th17 pathway was confirmed via IL-17A blockade experiments. Compared to the aluminum-adjuvanted vaccine, the 25%NPs-rClfA nano-vaccine elicited lower specific antibody titers but generated antibodies with superior neutralizing activity. It significantly enhanced the secretion of IFN-γ and IL-17A, with IL-17A sustaining elevated levels over an extended period. Crucially, the nano-vaccine conferred 100% protection against death following lethal S. aureus challenge. Mechanistically, it enhanced neutrophil phagocytosis and ROS production-key processes for bacterial clearance. Blockade of the Th17 pathway abrogated vaccine protection, demonstrating that IL-17A is essential for its efficacy. This study demonstrates that the PLGA-PEG nanoparticle-based rClfA nano-vaccine can effectively redirect immune responses toward protective Th1/Th17 immunity and robustly protect against lethal S. aureus infection, largely through an IL-17A-dependent mechanism. These findings provide important experimental and theoretical support for the translational development of S. aureus vaccines.