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Nature Communications Oct 2023The sudden mortality of African elephants (Loxodonta africana) in Botswana and Zimbabwe in 2020 provoked considerable public interest and speculation. Poaching and...
The sudden mortality of African elephants (Loxodonta africana) in Botswana and Zimbabwe in 2020 provoked considerable public interest and speculation. Poaching and malicious poisoning were excluded early on in the investigation. Other potential causes included environmental intoxication, infectious diseases, and increased habitat stress due to ongoing drought. Here we show evidence of the mortalities in Zimbabwe as fatal septicaemia associated with Bisgaard taxon 45, an unnamed close relative of Pasteurella multocida. We analyse elephant carcasses and environmental samples, and fail to find evidence of cyanobacterial or other intoxication. Post-mortem and histological findings suggest a bacterial septicaemia similar to haemorrhagic septicaemia caused by P. multocida. Biochemical tests and 16S rDNA analysis of six samples and genomic analysis of one sample confirm the presence of Bisgaard taxon 45. The genome sequence contains many of the canonical P. multocida virulence factors associated with a range of human and animal diseases, including the pmHAS gene for hyaluronidase associated with bovine haemorrhagic septicaemia. Our results demonstrate that Bisgaard taxon 45 is associated with a generalised, lethal infection and that African elephants are susceptible to opportunistically pathogenic Pasteurella species. This represents an important conservation concern for elephants in the largest remaining metapopulation of this endangered species.
Topics: Humans; Animals; Cattle; Hemorrhagic Septicemia; Elephants; Pasteurella; Pasteurella multocida; Ecosystem
PubMed: 37880229
DOI: 10.1038/s41467-023-41987-z -
The Journal of Antimicrobial... Sep 2023
Topics: Mannheimia haemolytica; Anti-Bacterial Agents; Drug Resistance, Bacterial; Macrolides; Pasteurella multocida
PubMed: 37533327
DOI: 10.1093/jac/dkad209 -
Microbiology Spectrum Jun 2023Avibacterium paragallinarum is the pathogen involved in infectious coryza (IC), an acute infectious upper respiratory disease in chickens. The prevalence of IC has...
Avibacterium paragallinarum is the pathogen involved in infectious coryza (IC), an acute infectious upper respiratory disease in chickens. The prevalence of IC has increased in China in recent years. There is a lack of reliable and effective procedures for gene manipulation, which has limited the research on the bacterial genetics and pathogenesis of A. paragallinarum. Natural transformation has been developed as a method of gene manipulation in by the introduction of foreign genes or DNA fragments into bacterial cells, but there has been no report on natural transformation in . In this study, we analyzed the existence of homologous genetic factors and competence proteins underlying natural transformation in and established a method for transformation in it. Through bioinformatics analysis, we identified 16 homologs of Haemophilus influenzae competence proteins in . We found that the uptake signal sequence (USS) was overrepresented in the genome of (1,537 to 1,641 copies of the core sequence ACCGCACTT). We then constructed a plasmid, pEA-KU, that carries the USS and a plasmid, pEA-K, without the USS. These plasmids can be transferred via natural transformation into naturally competent strains of . Significantly, the plasmid that carries USS showed a higher transformation efficiency. In summary, our results demonstrate that has the ability to undergo natural transformation. These findings should prove to be a valuable tool for gene manipulation in . Natural transformation is an important mechanism for bacteria to acquire exogenous DNA molecules during the process of evolution. Additionally, it can also be used as a method to introduce foreign genes into bacteria under laboratory conditions. Natural transformation does not require equipment such as an electroporation apparatus. It is easy to perform and is similar to gene transfer under natural conditions. However, there have been no reports on natural transformation in Avibacterium paragallinarum. In this study, we analyzed the presence of homologous genetic factors and competence proteins underlying natural transformation in . Our results indicate that natural competence could be induced in serovars A, B, and C. Furthermore, the method that we established to transform plasmids into naturally competent strains was stable and efficient.
Topics: Animals; Haemophilus Infections; Poultry Diseases; Chickens; Pasteurellaceae; Haemophilus paragallinarum
PubMed: 37212663
DOI: 10.1128/spectrum.05209-22 -
BMC Oral Health Oct 2020The aim of this study was to assess the association between serum and salivary Immunoglobulin (Ig) Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans)...
BACKGROUND
The aim of this study was to assess the association between serum and salivary Immunoglobulin (Ig) Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) specific antibodies in healthy controls (HC) and periodontitis (PT) patients. Furthermore, the objectives were to determine whether PT influenced serum A. actinomycetemcomitans specific antibodies and whether serum or salivary antibodies against A. actinomycetemcomitans IgG were mediated by serum high-sensitivity c-reactive protein (hs-CRP).
METHODS
Fifty-three patients with periodontitis and 48 HC were enrolled in the present study. Patients were regularly examined and characterized by clinical, salivary and blood samples analyses. A. actinomycetemcomitans IgA and IgG antibodies and hs-CRP were evaluated using a commercially available kit. The Spearman Correlation Test and Jonckheere-Terpstra Test were applied in order to assess the interdependence between serum A. actinomycetemcomitans IgG antibodies and clinical periodontal parameters. To evaluate the dependence of the serum and salivary A. actinomycetemcomitans IgG levels from possible confounders, univariate and multivariable linear regression analyses were performed.
RESULTS
Compared to HC, patients with PT had significantly higher IgA [serum: PT, 1.89 (1.2-2.2) EU vs HC, 1.37 (0.9-1.8) EU (p = 0.022); saliva: PT, 1.67 (1.4-2.1) EU vs HC, 1.42 (0.9-1.6) EU (p = 0.019)] and A. actinomycetemcomitans IgG levels [serum: PT, 2.96 (2.1-3.7) EU vs HC, 2.18 (1.8-2.1) EU (p < 0.001); saliva, PT, 2.19 (1.8-2.5) EU vs HC, 1.84 (1.4-2) EU (p = 0.028)]. In PT patients, serum A. actinomycetemcomitans IgG were associated with a proportional extent of PT and tooth loss (P-trend value< 0.001). The univariate regression analysis demonstrated that PT (p = 0.013) and high hs-CRP (p < 0.001) had a significant negative effect on serum and salivary A. actinomycetemcomitans IgG levels. The multivariate regression analysis showed that PT (p = 0.033), hs-CRP (p = 0.014) and BMI (p = 0.017) were significant negative predictors of serum A. actinomycetemcomitans IgG while hs-CRP (p < 0.001) and BMI (P = 0.025) were significant negative predictors of salivary A. actinomycetemcomitans IgG.
CONCLUSIONS
PT patients presented a significantly higher serum and salivary A. actinomycetemcomitans IgA and IgG compared to HC. There was a significant increase in serum A. actinomycetemcomitans IgG when patients presented a progressive extent of PT. Moreover, PT and hs-CRP were significant negative predictors of increased salivary and serum A. actinomycetemcomitans IgG levels.
TRIAL REGISTRATION
The study was retrospectively registered at clinicaltrials.gov ( NCT04417322 ).
Topics: Aggregatibacter actinomycetemcomitans; Antibodies, Bacterial; Humans; Immunoglobulin A, Secretory; Periodontitis; Saliva
PubMed: 33059645
DOI: 10.1186/s12903-020-01258-5 -
ACS Infectious Diseases Feb 2024is a commensal of the human upper respiratory tract that can infect diverse host niches due, at least in part, to its ability to withstand both endogenous and...
is a commensal of the human upper respiratory tract that can infect diverse host niches due, at least in part, to its ability to withstand both endogenous and host-mediated oxidative stresses. Here, we show that , a gene previously linked to iron import, is essential for manganese recruitment the HfeBCD transporter. Structural analyses show that metal binding in HfeA uses a unique mechanism that involves substantial rotation of the C-terminal lobe of the protein. Disruption of reduced manganese acquisition and was associated with decreased growth under aerobic conditions, impaired manganese-superoxide dismutase activity, reduced survival in macrophages, and changes in biofilm production in the presence of superoxide. Collectively, this work shows that HfeA contributes to manganese acquisition and virulence attributes. High conservation of the permease in species suggests that it may serve similar roles in other pathogenic Pasteurellaceae.
Topics: Humans; Haemophilus influenzae; Membrane Transport Proteins; Manganese; Biofilms; Homeostasis
PubMed: 38240689
DOI: 10.1021/acsinfecdis.3c00407 -
Toxins Jan 2022Leukotoxin A (LtxA) is the major virulence factor of an oral bacterium known as (). LtxA is associated with elevated levels of anti-citrullinated protein antibodies... (Review)
Review
Leukotoxin A (LtxA) is the major virulence factor of an oral bacterium known as (). LtxA is associated with elevated levels of anti-citrullinated protein antibodies (ACPA) in rheumatoid arthritis (RA) patients. LtxA targets leukocytes and triggers an influx of extracellular calcium into cytosol. The current proposed model of LtxA-mediated hypercitrullination involves the dysregulated activation of peptidylarginine deiminase (PAD) enzymes to citrullinate proteins, the release of hypercitrullinated proteins through cell death, and the production of autoantigens recognized by ACPA. Although model-based evidence is yet to be established, its interaction with the host's immune system sparked interest in the role of LtxA in RA. The first part of this review summarizes the current knowledge of and LtxA. The next part highlights the findings of previous studies on the association of or LtxA with RA aetiology. Finally, we discuss the unresolved aspects of the proposed link between LtxA of and RA.
Topics: Aggregatibacter actinomycetemcomitans; Anti-Citrullinated Protein Antibodies; Arthritis, Rheumatoid; Exotoxins; Humans; Pasteurellaceae Infections
PubMed: 35051027
DOI: 10.3390/toxins14010050 -
Journal of Clinical Periodontology Sep 2020The immune receptor triggering receptor expressed on myeloid cell-1 (TREM-1) is responsible for an amplification of the immuno-inflammatory response in inflammatory...
AIM
The immune receptor triggering receptor expressed on myeloid cell-1 (TREM-1) is responsible for an amplification of the immuno-inflammatory response in inflammatory diseases. Its role in the aetiopathogenesis of periodontitis is underexplored. The aim of this case-control and before-after study was to determine the evolution of soluble form of TREM-1 (sTREM-1) concentrations after scaling and root planing (SRP), and its prognostic value and evaluate associated microbial, periodontal and psychosocial factors.
METHODS
Gingival crevicular fluid was collected in two pathological sites (periodontal pocket depth (PPD) ≥ 5 mm) and one healthy site (PPD ≤ 3 mm) from thirty periodontitis patients (before/after SRP), and in one healthy site from thirty controls (patients without periodontal disease). Each patient filled-in stress/anxiety self-assessment questionnaires and provided a saliva sample. Diseased patients were followed for a total of 13-15 weeks in initial periodontal treatment. sTREM-1 and salivary cortisol levels were determined by ELISA and periodontopathogens by PCR.
RESULTS
Before SRP, higher crevicular sTREM-1 levels were positively associated with some increased clinical parameters (Plaque Index, tooth mobility, bleeding on probing, p < .05) and inversely with Aggregatibacter actinomycetemcomitans abundance (p = .03). No correlation with psychological factors nor cortisol was found with salivary sTREM-1 concentrations. After SRP, crevicular sTREM-1 levels decreased (p < .001) and were not linked to a PPD decrease but remained higher in pathological than in healthy sites (p < .001). Higher concentrations were also found out in unimproved sites (no change or increase in PPD) compared to improved ones (p = .02). Higher sTREM-1 levels were associated with Porphyromonas gingivalis, Treponema denticola and Campylobacter rectus in pathological sites after SRP (p < .05).
CONCLUSION
Crevicular sTREM-1 level decreased after SRP but did not appear to be a site outcome predictive factor of periodontal healing and remained an inflammatory parameter.
Topics: Aggregatibacter actinomycetemcomitans; Dental Scaling; Gingival Crevicular Fluid; Humans; Periodontal Attachment Loss; Periodontal Pocket; Root Planing
PubMed: 32602969
DOI: 10.1111/jcpe.13339 -
Respiratory Physiology & Neurobiology Sep 2023Pasteurella (P.) multocida commonly occurs in the upper respiratory tract of healthy domestic pets, especially cats and dogs. People become infected by biting,...
BACKGROUND
Pasteurella (P.) multocida commonly occurs in the upper respiratory tract of healthy domestic pets, especially cats and dogs. People become infected by biting, scratching or direct contact with the animal's saliva. Inflammation develops in the wound and limits itself to the skin and subcutaneous tissue. P. multocida may cause respiratory tract infections and severe life-threatening complications. The study aimed to identify the lower respiratory infection in humans caused by P. multocida, to determine the potential source of infection and the associated symptoms, comorbidities and applied treatment.
MATERIALS AND METHODS
Between January 2010 and September 2021, 14,258 patients underwent 16,255 routine flexible video bronchoscopy (FVB), and the same number of bronchoalveolar lavage fluid (BALF) samples for microbiological examination were taken.
RESULTS
Microbiological examinations of the BALF only allowed the identification of six patients with P. multocida infection. All persons reported multiple scratches or bites and licking or kissing by their pets in the past. Productive cough with expectoration of mucopurulent discharge was the predominant symptom.
CONCLUSIONS
A lower respiratory infection caused by P. multocida is not common in humans. It should be considered particularly in elderly patients with underlying diseases and exposure to cats and dogs.
Topics: Humans; Animals; Cats; Dogs; Aged; Pasteurella multocida; Pasteurella Infections; Pasteurella; Respiratory Tract Infections; Saliva
PubMed: 37331420
DOI: 10.1016/j.resp.2023.104091 -
Applied Microbiology and Biotechnology Aug 2022Vine shoots and surplus grape must were assessed as feedstocks for succinic acid production with Actinobacillus succinogenes and Basfia succiniproducens. After acidic...
Vine shoots and surplus grape must were assessed as feedstocks for succinic acid production with Actinobacillus succinogenes and Basfia succiniproducens. After acidic and enzymatic hydrolysis, vine shoots released 35-40 g/L total sugars. Both bacterial species produced 18-21 g/L succinic acid from this hydrolysate in 120 h. Regarding grape must fermentation, A. succinogenes clearly outperformed B. succiniproducens. Yeast extract (a source of organic nitrogen and vitamins) was the only additional nutrient needed by A. succinogenes to grow on grape must. Under mathematically optimized conditions (145.7 g/L initial sugars and 24.9 g/L yeast extract), A. succinogenes generated 88.9 ± 1.4 g/L succinic acid in 96 h, reaching a succinic acid yield of 0.66 ± 0.01 g/g and a sugar consumption of 96.64 ± 0.30%. Substrate inhibition was not observed in grape musts with 125-150 g/L initial sugars, provided that an adequate amount of yeast extract was available for bacteria. Alternative nitrogen sources to yeast extract (red wine lees, white wine lees, urea, NHCl, and choline chloride) were not suitable for A. succinogenes in grape must. KEY POINTS: • Vine shoots and surplus grape must were assessed for succinic acid bioproduction. • Succinic acid bioproduction was 21 g/L with vine shoots and 89 g/L with grape must. • Fermentation was efficient at high sugar loads if organic N supply was adequate.
Topics: Actinobacillus; Fermentation; Nitrogen; Succinic Acid; Sugars; Vitis
PubMed: 35821430
DOI: 10.1007/s00253-022-12063-1 -
BMC Oral Health May 2021Periodontal disease represents a major health concern. The administration of beneficial microbes has been increasing in popularity over efforts to manipulate the...
BACKGROUND
Periodontal disease represents a major health concern. The administration of beneficial microbes has been increasing in popularity over efforts to manipulate the microbes using antimicrobial agents. This study determined the ability of Streptococcus salivarius to inhibit IL-6 and IL-8 production by gingival fibroblasts when activated by periodontal pathogens and their effect on the salivary microbiome.
METHODS
Primary human gingival fibroblasts were challenged with Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum and a combination of all three. IL-6 and IL-8 cytokine release were measured. Using this same model, S. salivarius K12, M18 and different supernatant and whole-cell lysate fractions of S. salivarius K12 were administered to pathogen-induced fibroblasts. A patient study of healthy participants was also conducted to determine the effect S. salivarius K12 had on the native microbiome using 16S next generation sequence analysis.
RESULTS
All pathogens tested induced a significant IL-6 and IL-8 response. S. salivarius K12 or M18, did not exhibit an increase in inflammatory cytokines. When either of the probiotic strains were co-administered with a pathogen, there were significant reductions in both IL-6 and IL-8 release. This effect was also observed when gingival fibroblasts were pre-treated with either S. salivarius K12 or M18 and then stimulated with the oral pathogens. Chewing gum containing S. salivarius K12 did not alter the salivary microbiome and did not increase inflammatory markers in the oral cavity.
CONCLUSION
S. salivarius K12 and M18 prevented immune activation induced by periodontal disease pathogens. S. salivarius K12 did not alter the salivary microbiome or induce immune activation when administered as a chewing gum. These results warrant further study to determine if it may be an effective treatment in a model of periodontal disease.
Topics: Aggregatibacter actinomycetemcomitans; Fusobacterium nucleatum; Humans; Periodontal Diseases; Porphyromonas gingivalis; Streptococcus salivarius
PubMed: 33962608
DOI: 10.1186/s12903-021-01606-z