Publications by authors named "Peter Valentin-Weigand"

Introduction: Streptococcus pneumoniae is the most common cause of bacterial meningitis and meningoencephalitis in humans. The bacterium produces numerous virulence determinants, among them hydrogen peroxide (H2O2) and pneumolysin (Ply), which contribute to bacterial cytotoxicity. Microglia, the resident phagocytes in the brain, are distinct from other macrophages, and we thus compared their susceptibility to pneumococcal toxicity and their ability to phagocytose pneumococci with those of bone marrow-derived macrophages (BMDM).

View Article and Find Full Text PDF

Marine mammals are sentinel species representing the "health" of our oceans on which we are dependent. There are many threats to marine mammals including infectious diseases that increase with climate change and pollution of the marine environment. Streptococcus phocae has frequently been isolated from diseased or dead marine mammals.

View Article and Find Full Text PDF

is a porcine and zoonotic pathogen in the upper respiratory tract, expressing different capsular serotypes and virulence-associated factors. Given its genomic and phenotypic diversity, the virulence potential of cannot be attributed to a single factor. Since strong inflammatory response is a hallmark of infection, the objective of this study was to investigate the differences in transcriptional host responses to two serotype 2 and one serotype 9 strains.

View Article and Find Full Text PDF
Article Synopsis
  • The rise in livestock production is expected to lead to the emergence of new pathogens that can affect both animal and human health.
  • Researchers studied the respiratory microbiota of pigs, focusing on a specific pathogen that is prevalent in pig farming and can also infect humans.
  • The findings indicate that certain pathogenic strains developed during the expansion of pig farming in the 19th and 20th centuries, spreading globally through the trade of live pigs and adapting over time to become more pathogenic.
View Article and Find Full Text PDF
Article Synopsis
  • The text discusses how a common pig pathogen adapts to different environments in a pig's body, starting from respiratory infection and potentially spreading to organs like the heart and brain.
  • It emphasizes the importance of metabolism for the pathogen's survival and virulence, noting that mutations affecting metabolic regulators can weaken its ability to cause infection.
  • The review also suggests that exploring metabolic pathways could lead to new treatment strategies, especially in light of rising antimicrobial resistance, making the development of new antibiotics crucial.
View Article and Find Full Text PDF

is one of the most important porcine pathogens causing Glaesser's disease. Neutrophil granulocytes are the major counteracting cell type of the innate immune system, which contribute to the host defense by phagocytosis or the formation of neutrophil extracellular traps (NETs). Recently, NET-formation has been shown to facilitate the survival of bacteria from the family.

View Article and Find Full Text PDF

Streptococcus suis, a common member of the porcine respiratory microbiota, can cause life-threatening diseases in pigs as well as humans. A previous study identified the gene trpX as conditionally essential for in vivo survival by intrathecal infection of pigs with a transposon library of S. suis strain 10.

View Article and Find Full Text PDF

Highly pathogenic avian influenza viruses of the H5N8 subtype have been circulating in Europe and Asia since 2016, causing huge economic losses to the poultry industry. A new wave of H5Nx infections has begun in 2020. The viruses mainly infect wild birds and waterfowl; from there they spread to poultry and cause diseases.

View Article and Find Full Text PDF

The Gram-negative, obligate intracellular bacterium is the causative organism of the zoonosis Q fever and is known for its resistance toward various intra- and extracellular stressors. Infected ruminants such as cattle, sheep, and goats can shed the pathogen in their milk. Pasteurization of raw milk was introduced for the inactivation of and other milk-borne pathogens.

View Article and Find Full Text PDF

Streptococcus suis, an emerging zoonotic pathogen, causes invasive diseases in pigs, including sepsis, meningitis, endocarditis, pneumonia, and arthritis. Importantly, similar pathologies are reported in human S. suis infections.

View Article and Find Full Text PDF

pathogenicity island (SPI) 2 type three secretion system (T3SS)-mediated effector molecules facilitate bacterial survival in phagocytes but their role in the intestinal epithelium remains ill-defined. Using our neonatal murine infection model in combination with SPI2 reporter technology and RNA-Seq of sorted primary enterocytes, we demonstrate expression of SPI2 effector molecules by intraepithelial Typhimurium . Typhimurium).

View Article and Find Full Text PDF

A vaccine protecting against different Streptococcus suis serotypes is highly needed in porcine practice to improve animal welfare and reduce the use of antibiotics. We hypothesized that immunogens prominently recognized by convalescence sera but significantly less so by sera of susceptible piglets are putative protective antigens. Accordingly, we investigated immunogenicity and protective efficacy of a multicomponent vaccine including six main conserved immunogens, namely SSU0934, SSU1869, SSU0757, SSU1950, SSU1664 and SSU0187.

View Article and Find Full Text PDF

() is an important opportunistic pathogen, which can cause septicemia and meningitis in pigs and humans. Previous observations in -infected pigs revealed lesions at the choroid plexus (CP). experiments with primary porcine CP epithelial cells (PCPEC) and human CP epithelial papilloma (HIBCPP) cells demonstrated that can invade and traverse the CP epithelium, and that the CP contributes to the inflammatory response cytokine expression.

View Article and Find Full Text PDF

is a common pathogen colonising the respiratory tract of pigs. It can cause meningitis, sepsis and pneumonia leading to economic losses in the pig industry worldwide. Cyclooxygenase-2 (COX-2) and its metabolites play an important regulatory role in different biological processes like inflammation modulation and immune activation.

View Article and Find Full Text PDF

Marine mammals are sentinels for the marine ecosystem and threatened by numerous factors including infectious diseases. One of the most frequently isolated bacteria are beta-hemolytic streptococci. However, knowledge on ecology and epidemiology of streptococcal species in marine mammals is very limited.

View Article and Find Full Text PDF

Serotyping is the most common method to characterize field isolates of Actinobacillus (A.) pleuropneumoniae, the etiological agent of porcine pleuropneumonia. Based on serology, many farms seem to be infected and antibodies against a wide variety of serovars are detectable, but, so far it is unknown to what degree respective serovars contribute to outbreaks of clinical manifest disease.

View Article and Find Full Text PDF
Article Synopsis
  • The study investigates the interactions between major pathogens in pigs, focusing on their role in respiratory diseases and co-infections, specifically in the context of the porcine respiratory disease complex (PRDC).
  • The researchers created a precision-cut lung slice (PCLS) model to examine how an initial infection affects subsequent pathogen adherence, colonization, and cytotoxicity.
  • Findings suggest that pre-infection with one pathogen enhances the ability of a second pathogen to adhere and colonize, largely due to the reduction of ciliary activity, and highlights the importance of a specific toxin (suilysin) in this cytotoxic process.
View Article and Find Full Text PDF

Glaesserella parasuis is an important pathogen in swine production. It acts as a primary pathogen in systemic Glässer´s disease and as a secondary pathogen in Porcine Respiratory Disease Complex. In this study, a collection of 308 isolates from carrier animals and individuals with respiratory or Glässer´s disease isolated 2012-2019 in Germany was analysed.

View Article and Find Full Text PDF

is a zoonotic agent causing meningitis in pigs and humans. Neutrophils, as the first line of defense against infections, release neutrophil extracellular traps (NETs) to entrap pathogens. In this study, we investigated the role of the secreted nuclease A of (SsnA) as a NET-evasion factor in vivo and in vitro.

View Article and Find Full Text PDF

is a swine pathogen and a zoonotic agent afflicting people in close contact with infected pigs or pork meat. Sporadic cases of human infections have been reported worldwide. In addition, outbreaks emerged in Asia, making this bacterium a primary health concern in this part of the globe.

View Article and Find Full Text PDF

Actinobacillus (A.) pleuropneumoniae is one of the most important respiratory pathogens in global pig production. Antimicrobial treatment and vaccination provide only limited protection, but genetic disease resistance is a very promising alternative for sustainable prophylaxis.

View Article and Find Full Text PDF

() is a major cause of economic losses in the pig industry worldwide and is an emerging zoonotic pathogen. One important virulence-associated factor is suilysin (SLY), a toxin that belongs to the family of cholesterol-dependent pore-forming cytolysins (CDC). However, the precise role of SLY in host-pathogen interactions is still unclear.

View Article and Find Full Text PDF
Article Synopsis
  • * The H5N8 virus belongs to clade 2.3.4.4 B, indicating its specific genetic lineage.
  • * This strain of the virus was closely linked to other H5N8 avian viruses present in Europe during the same period.
View Article and Find Full Text PDF

Actinobacillus pleuropneumoniae (A.pp) causes severe pneumonia associated with enormous economic loss in pigs. Peracute diseased pigs die in <24 h with pneumonia.

View Article and Find Full Text PDF