Related Pathogens Research Articles

Survival and virulence of Acinetobacter baumannii in microbial mixtures

Acinetobacter species such as A. venetianus and A. guillouiae have been studied for various biotechnology applications, including bioremediation of recalcitrant and harmful environmental contaminants, as well as bioengineering of enzymes and diagnostic materials. Bacteria used in biotechnology are often combined with other microorganisms in mixtures to formulate efficacious commercial products. However, if the mixture contained a closely related Acinetobacter pathogen such as A. baumannii (Ab), it remains unclear whether the survival and virulence of Ab would be masked or augmented. This uncertainty poses a challenge in ensuring the safety of such biotechnology products, since Ab is one of the most significant pathogens for both hospital and community -acquired infections. This research aimed to investigate the growth and virulence of Ab within a mixture of 11 bacterial species formulated as a mock microbial mixture (MM). Growth challenges with environmental stressors (i.e., temperature, pH, sodium, iron, and antibiotics) revealed that Ab could thrive under diverse conditions except in the presence of ciprofloxacin. When cultured alone, Ab exhibited significantly more growth in the presence of almost all the environmental stressors than when it was co-incubated with the MM. During the exposure of A549 lung epithelial cells to the MM, Ab growth was stimulated compared to that in standard mammalian culture media. Cytotoxicity caused by Ab was suppressed in the presence of the MM. Lymphocytes were significantly reduced in mice exposed to Ab with or without MM via intravenous injection. The levels of the splenic cytokines IL-1α, IL-1β, MCP-1, and MIP-1α were significantly reduced 24 h after exposure to Ab + MM. This study demonstrated that the presence of the MM marginally but significantly reduced the growth and virulence of Ab, which has implications for the safety of mixtures of microorganisms for biotechnological applications. Furthermore, these findings expand our understanding of the virulence of Ab during host–pathogen interactions.

Analysis of the Pathogen Distribution and Antimicrobial Resistance after Plastic Surgery of the Urogenital System.

We aimed to summarize the distribution of pathogenic bacteria for postoperative infection of different genitourinary plastic surgery and the antimicrobial resistance of the major pathogens. Between January 2011 and December 2021, following plastic surgery of the urogenital system, microbial strains from infected patients were collected, identified, and counted. The antibiotic sensitivity and distribution characteristics of common pathogens in relation with the surgical procedures were studied by WHONET 5.6, along with the main bacteria accounting for early infection. A total of 76 cases were included in the study. Among these, 53 Gram-negative bacteria were detected, with Escherichia coli (18 of 53) and Pseudomonas aeruginosa (nine of 53) accounting for the majority. There were also 23 Gram-positive bacteria, among which Staphylococcus aureus (six of 23) and Coagulase-negative Staphylococcus (five of 23) were the most common. In terms of antimicrobial resistance, E. coli was highly sensitive to amikacin, piperacillin/tazobactam, cefoxitin, and imipenem, whereas P. aeruginosa was highly sensitive to gentamicin, amikacin, cefepime, piperacillin/tazobactam, imipenem, ceftazidime, and ciprofloxacin. Procedures for urethral repair, urethral reconstruction, and lump resection were most commonly associated with infection. Among these, urethral repair was responsible for the majority of infections. The pathogenic bacteria involved in postoperative infections varied overall, but the most prevalent was E. coli. Gram-negative bacteria are the major cause of infection following genitourinary plastic surgery. The specific bacterial strains, degrees of antimicrobial resistance, and length of infection varied among the various procedures. The results of this study may provide references for clinical medication and the prevention and control of such infections.

Effects of pollination and plant genotype on Ustilago maydis disease development on the ears of maize inbreds and maize‐teosinte near‐isogenic lines

AbstractUstilago maydis, the fungus that causes corn smut disease, leads to significant economic losses in maize cultivars. A key feature of successful plant pathogens is their ability to utilize the plant–pathogen relationship to influence disease progression. Greenhouse experiments examined how pollination and plant genotype affect disease incidence and severity of U. maydis infection. Four U. maydis susceptible maize inbreds (B73, H95, Mo17, and Golden Bantam), and two U. maydis resistant maize‐teosinte near‐isogenic lines (NIL1 and NIL2) were utilized for this work. Three‐hundred and sixty plants (pollinated and unpollinated) from the six plant genotypes were inoculated with U. maydis and assessed based on five phenotypic traits [(1) disease incidence, (2) gall number, (3) gall weight, (4) disease severity, and (5) area under disease progress curve]. All pollinated plants demonstrated significantly (p < .001) lower disease incidence, gall number, gall weight, area under the disease progress curve, and severity in comparison to the unpollinated plants. Both pollinated resistant NILs demonstrated significantly (p < .001) less disease development than the pollinated susceptible maize plants and two unpollinated NILs. Therefore, disease resistance to U. maydis was dependent upon pollination and plant genotype. This provides novel evidence that pollination can significantly improve resistance to U. maydis in different plant genotypes. Enhanced disease resistance observed in the resistant NILs after pollination indicates pollination‐mediated resistance is one of the resistance mechanisms functioning in the resistant NILs. Integration of pollination‐mediated resistance and resistance introgressed from a maize progenitor will be useful for improving resistance to U. maydis and management of the disease.

Evolution of a Eukaryotic Transcription Factor's co-TF Dependence Involves Multiple Intrinsically Disordered Regions Affecting Activation and Autoinhibition.

Combinatorial control by multiple transcription factors (TFs) is a hallmark of eukaryotic gene regulation. Despite its prevalence and crucial roles in enhancing specificity and integrating information, the mechanisms behind why eukaryotic TFs depend on one another, and whether such interdependence evolves, are not well understood. We exploit natural variation in co-TF dependence in the yeast phosphate starvation (PHO) response to address this question. In the model yeast Saccharomyces cerevisiae, the main TF, Pho4, relies on the co-TF Pho2 to regulate ~28 genes. In a related yeast pathogen, Candida glabrata, its Pho4 exhibits significantly reduced Pho2 dependence and has an expanded target set of ~70 genes. Biochemical analyses showed C. glabrata Pho4 (CgPho4) binds to the same consensus motif with 3-4-fold higher affinity than ScPho4 does. A machine-learning-based prediction and yeast one-hybrid assay identified two Intrinsically Disordered Regions (IDRs) in CgPho4 that boost the activity of the main activation domain but showed little to no activity on their own. We also found evidence for autoinhibition behind the co-TF dependence in ScPho4. An IDR in ScPho4 next to its DNA binding domain was found to act as a double-edged sword: it both allows for enhanced activity with Pho2, and inhibits Pho4's activity without Pho2. This study provides a detailed molecular picture of how co-TF dependence is mediated and how its evolution, mainly driven by IDR divergence, can lead to significant rewiring of the regulatory network.

Mechanisms of antibody-dependent enhancement of infectious disease.

Antibody-dependent enhancement (ADE) of infectious disease is a phenomenon whereby host antibodies increase the severity of an infection. It is well established in viral infections but ADE also has an underappreciated role during bacterial, fungal and parasitic infections. ADE can occur during both primary infections and re-infections with the same or a related pathogen; therefore, understanding the underlying mechanisms of ADE is critical for understanding the pathogenesis and progression of many infectious diseases. Here, we review the four distinct mechanisms by which antibodies increase disease severity during an infection. We discuss the most established mechanistic explanation for ADE, where cross-reactive, disease-enhancing antibodies bound to pathogens interact with Fc receptors, thereby enhancing pathogen entry or replication, ultimately increasing the total pathogen load. Additionally, we explore how some pathogenic antibodies can shield bacteria from complement-dependent killing, thereby enhancing bacterial survival. We interrogate the molecular mechanisms by which antibodies can amplify inflammation to drive severe disease, even in the absence of increased pathogen replication. We also examine emerging roles for autoantibodies in enhancing the pathogenesis of infectious diseases. Finally, we discuss how we can leverage these insights to improve vaccine design and future treatments for infectious diseases.

Endogenous retrovirus ERV-DC8 highly integrated in domestic cat populations is a replication-competent provirus

Endogenous retroviruses (ERVs) are remnants of ancient retroviral infections in vertebrate genomes and are inherited by offspring. ERVs can produce pathogenic viruses through gene mutations or recombination. ERVs in domestic cats (ERV-DCs) generate feline leukemia virus subgroup D (FeLV-D) through viral recombination. Herein, we characterized the locus ERV-DC8, on chromosome B1, as an infectious replication-competent provirus. ERV-DC8 infected several cell lines, including human cells. Transmission electron microscopy of ERV-DC8 identified the viral release as a Gammaretrovirus. ERV-DC8 was identified as the FeLV-D viral interference group, with feline copper transporter 1 as its viral receptor. Insertional polymorphism analysis showed high ERV-DC8 integration in domestic cats. This study highlights the role, pathogenicity, and evolutionary relationships between ERVs and their hosts.

Rapid and label-free influenza A virus subtyping using surface-enhanced Raman spectroscopy with incident-wavelength analysis.

Early virus identification is a key component of both patient treatment and epidemiological monitoring. In the case of influenza A virus infections, where the detection of subtypes associated with bird flu in humans could lead to a pandemic, rapid subtype-level identification is important. Surface-enhanced Raman spectroscopy coupled with machine learning can be used to rapidly detect and identify viruses in a label-free manner. As there is a range of available excitation wavelengths for performing Raman spectroscopy, we must choose the best one to permit discrimination between highly similar subtypes of a virus. We show that the spectra produced by influenza A subtypes H1N1 and H3N2 exhibit a higher degree of dissimilarity when using 785 nm excitation wavelength in comparison with 532 nm excitation wavelength. Furthermore, the cross-validated area under the curve (AUC) for identification was higher for the 785 nm excitation, reaching 0.95 as compared to 0.86 for 532 nm. Ultimately, this study suggests that exciting with a 785 nm wavelength is better able to differentiate two closely related influenza viruses and likely can extend to other closely related pathogens.

Oomycete Metabolism Is Highly Dynamic and Reflects Lifestyle Adaptations.

The selective pressure of pathogen-host symbiosis drives adaptations. How these interactions shape the metabolism of pathogens is largely unknown. Here, we use comparative genomics to systematically analyze the metabolic networks of oomycetes, a diverse group of eukaryotes that includes saprotrophs as well as animal and plant pathogens, with the latter causing devastating diseases with significant economic and/or ecological impacts. In our analyses of 44 oomycete species, we uncover considerable variation in metabolism that can be linked to lifestyle differences. Comparisons of metabolic gene content reveal that plant pathogenic oomycetes have a bipartite metabolism consisting of a conserved core and an accessory set. The accessory set can be associated with the degradation of defense compounds produced by plants when challenged by pathogens. Obligate biotrophic oomycetes have smaller metabolic networks, and taxonomically distantly related biotrophic lineages display convergent evolution by repeated gene losses in both the conserved as well as the accessory set of metabolisms. When investigating to what extent the metabolic networks in obligate biotrophs differ from those in hemibiotrophic plant pathogens, we observe that the losses of metabolic enzymes in obligate biotrophs are not random and that gene losses predominantly influence the terminal branches of the metabolic networks. Our analyses represent the first metabolism-focused comparison of oomycetes at this scale and will contribute to a better understanding of the evolution of oomycete metabolism in relation to lifestyle adaptation. Numerous oomycete species are devastating plant pathogens that cause major damage in crops and natural ecosystems. Their interactions with hosts are shaped by strong selection, but how selection affects adaptation of the primary metabolism to a pathogenic lifestyle is not yet well established. By pan-genome and metabolic network analyses of distantly related oomycete pathogens and their nonpathogenic relatives, we reveal considerable lifestyle- and lineage-specific adaptations. This study contributes to a better understanding of metabolic adaptations in pathogenic oomycetes in relation to lifestyle, host, and environment, and the findings will help in pinpointing potential targets for disease control. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Movement-driven modelling reveals new patterns in disease transmission networks.

Interspecific interactions are highly relevant in the potential transmission of shared pathogens in multi-host systems. In recent decades, several technologies have been developed to study pathogen transmission, such as proximity loggers, GPS tracking devices and/or camera traps. Despite the diversity of methods aimed at detecting contacts, the analysis of transmission risk is often reduced to contact rates and the probability of transmission given the contact. However, the latter process is continuous over time and unique for each contact, and is influenced by the characteristics of the contact and the pathogen's relationship with both the host and the environment. Our objective was to assess whether a more comprehensive approach, using a movement-based model which assigns a unique transmission risk to each contact by decomposing transmission into contact formation, contact duration and host characteristics, could reveal disease transmission dynamics that are not detected with more traditional approaches. The model was built from GPS-collar data from two management systems in Spain where animal tuberculosis (TB) circulates: a national park with extensively reared endemic cattle, and an area with extensive free-range pigs and cattle farms. In addition, we evaluated the effect of the GPS device fix rate on the performance of the model. Different transmission dynamics were identified between both management systems. Considering the specific conditions under which each contact occurs (i.e. whether the contact is direct or indirect, its duration, the hosts characteristics, the environmental conditions, etc.) resulted in the identification of different transmission dynamics compared to using only contact rates. We found that fix intervals greater than 30 min in the GPS tracking data resulted in missed interactions, and intervals greater than 2 h may be insufficient for epidemiological purposes. Our study shows that neglecting the conditions under which each contact occurs may result in a misidentification of the real role of each species in disease transmission. This study describes a clear and repeatable framework to study pathogen transmission from GPS data and provides further insights to understand how TB is maintained in multi-host systems in Mediterranean environments.

CemR atypical response regulator impacts energy conversion in Campylobacteria.

C. jejuni and A. butzleri are closely related pathogens that infect the human gastrointestinal tract. In order to infect humans successfully, they need to change their metabolism as nutrient and respiratory conditions change. A regulator called CemR has been identified, which helps them adapt their metabolism to changing conditions, particularly oxygen availability in the gastrointestinal tract so that they can produce enough energy for survival and spread. Without CemR, these bacteria, as well as a related species, Helicobacter pylori, produce less energy, grow more slowly, or, in the case of C. jejuni, do not grow at all. Furthermore, CemR is a global regulator that controls the synthesis of many genes in each species, potentially allowing them to adapt to their ecological niches as well as establish infection. Therefore, the identification of CemR opens new possibilities for studying the pathogenicity of C. jejuni and A. butzleri.

Rapid Genomic Characterization of High-Risk, Antibiotic Resistant Pathogens Using Long-Read Sequencing to Identify Nosocomial

Background: Current epidemiological methods have limitations in identifying transmission of bacteria causing healthcare-associated infections (HAIs). Recent whole genome sequencing (WGS) studies found that genetically related strains can cause HAIs without meeting standard epidemiologic definitions, but these results could not provide data in a timely fashion needed for intervention. Given recent advances in Oxford Nanopore Technologies (ONT) sequencing, we sought to establish a validated ONT pipeline capable of providing accurate WGS-based comparisons of clinical pathogens within a short time frame that would allow for infection control interventions. Method: Using electronic medical record data, we identified potential healthcare acquisition of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and carbapenem-resistant gram-negative rods. Bacterial genomic DNA was directly extracted from clinical microbiology lab plates. Sequencing was conducted with the ONT MinION sequencer and R10.4.1 flow cell. MINTyper for single nucleotide polymorphism (SNP) calling and Ridom SeqSphere+ for core genome MLST were used to determine genetic relatedness. The main outcome was time from pathogen identification to completed genetic analysis. Result: The weekly workflow, from genomic DNA extraction to complete data analysis, averaged 2.6 days with a standard deviation of 1.3 days. (range: 1 to 6 days). Starting in August 2023, we have sequenced a total of 177 bacterial isolates from 156 unique patients. Isolates came from blood (38%), tissue/wound/body fluid (24%), urinary tract (20%), respiratory tract (16%), and rectal swab (2%). To date, six genetically related clusters have been identified. Three clusters involved ST117 vancomycin-resistant Enterococcus faecium (VREfm), comprising a total of 13 unique patients distributed as 2, 3, and 8 patients in each group, with pairwise SNP differences of 20, 11, and 14. Patients within the same clusters showed epidemiological links through overlapping admissions and temporally shared ICU stays. Additionally, another cluster consisted of five genetically related ST633 Pseudomonas aeruginosa isolates, with a pairwise SNP difference of 57.5. Each patient in this cluster had potential epidemiological links through overlapping admission times, despite the absence of identified shared spaces. The last two clusters involved Klebsiella pneumoniae and Escherichia coli (two cases each), with pairwise SNP differences of 18 and 9, respectively. In both cases, each patient showed potential epidemiological links through overlapping admission times. Conclusion: Our stand-alone ONT pipeline was able to rapidly and accurately detect genetically related AMR pathogens, aligning closely with epidemiological data. Our approach has the potential to assist in the efficient detection and deployment of preventative measures against healthcare-associated infection transmission.

Detection and public health risks of Salmonella spp and other pathogens in eggs

Salmonellosis and some other illnesses have been documented to be acquired through consumption of infected raw or undercooked foods such as eggs. Large population of human and animals around the Federal Capital Territory (F.C.T.), Abuja could be at risk due to the high consumption of this important food materials. Therefore, the aim of this study was to isolate and identify Salmonella spp and the related bacteria pathogens from the eggshells and the egg contents of samples obtained from five (5) deep liter farms within the FCT, Abuja, Nigeria. A total number of 150 samples of eggs, 30 each from the selected deep liter farms viz; Lugbe, Abaji, Kuje, Gwagwalada and Madalla were analyzed for the presence of Salmonella spp. and other pathogens using conventional culture method. The results revealed that 20.8% of the total bacteria count from all the egg content were contaminated with Salmonella spp. Other bacteria pathogens like E. coli, Staphylococcus aureus were isolated from both the egg shells and the egg contents. The observation was similar to literatures but the occurrence of these pathogens in the egg content was higher than expected. Therefore, the present study provides a recent data-generation of the prevalence of S. typhimurium and other pathogens in eggs at farm level in the selected locations in the FCT, Nigeria. It is important to remember that necessary control is required at all levels in the egg production chain and strict hygiene is needed to avoid epidemic resulting from the consumption of eggs.

Higher prevalence of sacbrood virus in Apis mellifera (Hymenoptera: Apidae) colonies after pollinating highbush blueberries.

Highbush blueberry pollination depends on managed honey bees (Apis mellifera) L. for adequate fruit sets; however, beekeepers have raised concerns about the poor health of colonies after pollinating this crop. Postulated causes include agrochemical exposure, nutritional deficits, and interactions with parasites and pathogens, particularly Melisococcus plutonius [(ex. White) Bailey and Collins, Lactobacillales: Enterococcaceae], the causal agent of European foulbrood disease, but other pathogens could be involved. To broadly investigate common honey bee pathogens in relation to blueberry pollination, we sampled adult honey bees from colonies at time points corresponding to before (t1), during (t2), at the end (t3), and after (t4) highbush blueberry pollination in British Columbia, Canada, across 2 years (2020 and 2021). Nine viruses, as well as M. plutonius, Vairimorpha ceranae, and V. apis [Tokarev et al., Microsporidia: Nosematidae; formerly Nosema ceranae (Fries et al.) and N. apis (Zander)], were detected by PCR and compared among colonies located near and far from blueberry fields. We found a significant interactive effect of time and blueberry proximity on the multivariate pathogen community, mainly due to differences at t4 (corresponding to ~6 wk after the beginning of the pollination period). Post hoc comparisons of pathogens in near and far groups at t4 showed that detections of sacbrood virus (SBV), which was significantly higher in the near group, not M. plutonius, was the primary driver. Further research is needed to determine if the association of SBV with highbush blueberry pollination is contributing to the health decline that beekeepers observe after pollinating this crop.

Haemosporidian parasites (Apicomplexa, Haemosporida) of breeding common starling Sturnus vulgaris in Latvia

Migratory behaviour in seasonal environments affects host–pathogen relationships, especially for vector‐transmitted blood parasites of the order Haemosporida. The common starling Sturnus vulgaris is a short‐distance migrant where the north‐eastern European breeding population spend the non‐breeding season in temperate mild western Europe. Despite the high abundance and known susceptibility as a host, blood parasitism in wild starlings has rarely been studied with molecular methods. Here, we monitored haemosporidian parasitism in a Latvian starling population over four breeding seasons. We found a total annual parasite prevalence of 2.7–15.7% caused by four Haemoproteus, three Plasmodium, and one Leucocytozoon cytochrome‐b (cyt‐b) genetic lineages. Herein, seven of these lineages have been recorded for the first time in the common starling as host. Lineage‐specific parasitemia was generally low (Haemoproteus range: 0.008–1.028%, Plasmodium range: 0.002–0.005%, Leucocytozoon range: 0.003–0.004%) indicating chronic infection stages in all parasitised hosts during the breeding season. Additionally, the proportion of leukocytes in peripheral blood was enhanced in infected compared to non‐infected hosts indicating activated immune defence during the chronic infection stage. Finally, 11% (3 out of 27) of individuals had cleared the infection from peripheral blood after one year. Causes for the variability in infection prevalence in common starlings across years, as well as the transmission period during the host annual cycle, are still open for future studies.

Streptococcus dysgalactiae subsp. equisimilis infection and its intersection with Streptococcus pyogenes.

SUMMARYStreptococcus dysgalactiae subsp. equisimilis (SDSE) is an increasingly recognized cause of disease in humans. Disease manifestations range from non-invasive superficial skin and soft tissue infections to life-threatening streptococcal toxic shock syndrome and necrotizing fasciitis. Invasive disease is usually associated with co-morbidities, immunosuppression, and advancing age. The crude incidence of invasive disease approaches that of the closely related pathogen, Streptococcus pyogenes. Genomic epidemiology using whole-genome sequencing has revealed important insights into global SDSE population dynamics including emerging lineages and spread of anti-microbial resistance. It has also complemented observations of overlapping pathobiology between SDSE and S. pyogenes, including shared virulence factors and mobile gene content, potentially underlying shared pathogen phenotypes. This review provides an overview of the clinical and genomic epidemiology, disease manifestations, treatment, and virulence determinants of human infections with SDSE with a particular focus on its overlap with S. pyogenes. In doing so, we highlight the importance of understanding the overlap of SDSE and S. pyogenes to inform surveillance and disease control strategies.

Key periodontal pathogens may mediate potential pathogenic relationships between periodontitis and crohn’s disease

BackgroundCrohn’s disease (CD)-associated periodontitis is common. However, the role of periodontal pathogens in the Coexistence of CD and periodontal disease remains unclear.MethodsTo investigate the potential relationship mediated by periodontal pathogens between periodontitis and CD, we collected salivary samples from healthy participants (H group, n = 12), patients with CD (Ch group, n = 10), patients with periodontitis (Ps group, n = 12), and patients with Coexistence of CD and periodontal disease (Cp group, n = 12) and analyzed them by 16 S rRNA sequencing.ResultsPatients with Coexistence of CD and periodontal disease had increased levels of Fusobacterium, Actinomyces, Leptotrichia, and Prevotella, which correlated with the severity of periodontitis. Conversely, the levels of Streptococcus, Neisseria, Haemophilus, and Gemella, which decreased in Coexistence of CD and periodontal disease, were negatively correlated with the severity of periodontitis. To further investigate the role of periodontal pathogens in CD development, representative periodontal pathogens causing periodontitis, Porphyromonas gingivalis and Fusobacterium nucleatum, were administered to mice. These pathogens migrate to, and colonize, the gut, accelerating CD progression and aggravating colitis, and even systemic inflammation. In vitro experiments using a Caco-2/periodontal pathogen coculture revealed that P. gingivalis and F. nucleatum increased intestinal permeability by directly disrupting the tight junctions of intestinal epithelial cells.ConclusionOur findings strongly suggest that periodontal pathogens play a role in the relationship between periodontitis and CD. These results provide a basis for understanding the pathogenesis of Coexistence of CD and periodontal disease and may lead to the development of novel therapeutic strategies.

DNA binding is rate-limiting for natural transformation.

Bacteria take up environmental DNA using dynamic appendages called type IV pili (T4P) to elicit horizontal gene transfer in a process called natural transformation. Natural transformation is widespread amongst bacteria yet determining how different factors universally contribute to or limit this process across species has remained challenging. Here we show that Acinetobacter baylyi, the most naturally transformable species, is highly transformable due to its ability to robustly bind nonspecific DNA via a dedicated orphan minor pilin, FimT. We show that, compared to its homologues, A. baylyi FimT contains multiple positively charged residues that additively promote DNA binding efficiency. Expression of A. baylyi FimT in a closely related Acinetobacter pathogen is sufficient to substantially improve its capacity for natural transformation, demonstrating that T4P-DNA binding is a rate-limiting step in this process. These results demonstrate the importance of T4P-DNA binding efficiency in driving natural transformation, establishing a key factor limiting horizontal gene transfer.

Conservation of HLA Spike Protein Epitopes Supports T Cell Cross-Protection in SARS-CoV-2 Vaccinated Individuals against the Potentially Zoonotic Coronavirus Khosta-2.

Heterologous vaccines, which induce immunity against several related pathogens, can be a very useful and rapid way to deal with new pandemics. In this study, the potential impact of licensed COVID-19 vaccines on cytotoxic and helper cell immune responses against Khosta-2, a novel sarbecovirus that productively infects human cells, was analyzed for the 567 and 41 most common HLA class I and II alleles, respectively. Computational predictions indicated that most of these 608 alleles, covering more than 90% of the human population, contain sufficient fully conserved T-cell epitopes between the Khosta-2 and SARS-CoV-2 spike-in proteins. Ninety percent of these fully conserved peptides for class I and 93% for class II HLA molecules were verified as epitopes recognized by CD8+ or CD4+ T lymphocytes, respectively. These results show a very high correlation between bioinformatic prediction and experimental assays, which strongly validates this study. This immunoinformatics analysis allowed a broader assessment of the alleles that recognize these peptides, a global approach at the population level that is not possible with experimental assays. In summary, these findings suggest that both cytotoxic and helper cell immune protection elicited by currently licensed COVID-19 vaccines should be effective against Khosta-2 virus infection. Finally, by being rapidly adaptable to future coronavirus pandemics, this study has potential public health implications.

The bacterial patterns suggesting the dynamic features of tick-associated microorganisms in hard ticks

BackgroundTicks are blood-feeding significant arthropods that can harbour various microorganisms, including pathogens that pose health risks to humans and animals. Tick-symbiont microorganisms are believed to influence tick development, but the intricate interactions between these microbes and the relationships between different tick-borne microorganisms remain largely unexplored.ResultsBased on 111 tick pool samples presenting questing and engorged statuses including 752 questing tick and 1083 engorged tick from cattle and goats, which were collected in two types of geographic landscape (semi-desert and alpine meadow). We observed significant variations in the composition of tick-borne microorganisms across different environments and blood-engorgement statuses, with a pronounced divergence in symbionts compared to environmental bacteria. Metabolic predictions revealed over 90 differential pathways for tick-borne microorganisms in distinct environments and more than 80 metabolic variations in response to varying blood engorgement statuses. Interestingly, nine pathways were identified, particularly related to chorismate synthesis and carbohydrate metabolism. Moreover, microbial network relationships within tick-borne microorganism groups were highly distinct across different environments and blood-engorgement statuses. The microbial network relationships of symbionts involve some pathogenic and environmental microorganisms. Regression modelling highlighted positive correlations between the Coxiella symbiont and related pathogens, while some environmental bacteria showed strong negative correlations with Coxiella abundance. We also identified commensal bacteria/pathogens in bacterial cooccurrence patterns. Furthermore, we tested pathogenic microorganisms of each tick sample analysis revealed that 86.36% (1601/1855) of the tick samples carried one or more pathogenic microorganisms, The total carrier rate of bacterial pathogens was 43.77% ((812/1855). Most blood samples carried at least one pathogenic microorganism. The pathogens carried by the ticks have both genus and species diversity, and Rickettsia species are the most abundant pathogens among all pathogens.ConclusionOur findings underscore that the bacterial pattern of ticks is dynamic and unstable, which is influenced by the environment factors and tick developmental characteristics.

Fusarium pseudograminearum biomass and toxin accumulation in wheat tissues with and without Fusarium crown rot symptoms.

Fusarium crown rot (FCR) is an important and devastating disease of wheat (Triticum aestivum) caused by the fungus Fusarium pseudograminearum and related pathogens. Using two distinct susceptible cultivars, we investigated the isolation frequencies of F. pseudograminearum and quantified its biomass accumulation and the levels of the associated toxins deoxynivalenol (DON) and DON-3-glucoside (D3G) in inoculated field-grown wheat plants. We detected F. pseudograminearum in stem, peduncle, rachis, and husk tissues, but not in grains, whereas DON and D3G accumulated in stem, rachis, husk, and grain tissues. Disease severity was positively correlated with the frequency of pathogen isolation, F. pseudograminearum biomass, and mycotoxin levels. The amount of F. pseudograminearum biomass and mycotoxin contents in asymptomatic tissue of diseased plants were associated with the distance of the tissue from the diseased internode and the disease severity of the plant. Thus, apparently healthy tissue may harbor F. pseudograminearum and contain associated mycotoxins. This research helps clarify the relationship between F. pseudograminearum occurrence, F. pseudograminearum biomass, and mycotoxin accumulation in tissues of susceptible wheat cultivars with or without disease symptoms, providing information that can lead to more effective control measures.