Staphylococcus aureus Serine protease-like protein A (SplA) induces IL-8 by keratinocytes and synergizes with IL-17A

Altered gut microbiome-metabolite interactions link intestinal inflammation severity and MR enterography abnormalities in Crohn's disease

Altered gut microbiota‒metabolite interactions may result in intestinal inflammation severity variation in Crohn's disease (CD). Magnetic resonance enterography (MRE) advances anti-inflammatory strategy development. We aimed to identify inflammation-related multiomics factors and MRE interactions for CD management, analyzing 425 CD patients and 42 healthy controls undergoing MRE, ileocolonoscopy, and fecal/blood sampling (microbiota/metabolite analyses), with intestinal inflammation categorized by MRE and ileocolonoscopy. Ruminococcus species were enriched in CD patients versus healthy controls, while Pseudomonas and Staphylococcus dominated moderate-severe versus no-mild inflammation groups, suggesting inflammation-level associations. Ruminococcus gauvreauii suppressed intestinal inflammation by regulating serum PC(O-34:3), ePE(38:6), and ceramides (all p < 0.05). Serum N-acetylneuraminic acid and guanidinoacetic acid correlated with intestinal morphological changes (e.g., MRE-detectable effusion and wall thickness) and inflammation severity (P ACME < 0.05). A link was established between microscopic microbiota-metabolite markers and macroscopic imaging of inflammatory features, which could offer valuable insights into inflammation management.

Staphylococcus aureus in Inflammation and Pain: Update on Pathologic Mechanisms

Staphylococcus aureus (S. aureus) is a Gram-positive bacterium of significant clinical importance, known for its versatility and ability to cause a wide array of infections, such as osteoarticular, pulmonary, cardiovascular, device-related, and hospital-acquired infections. This review describes the most recent evidence of the pathogenic potential of S. aureus, which is commonly part of the human microbiota but can lead to severe infections. The prevalence of pathogenic S. aureus in hospital and community settings contributes to substantial morbidity and mortality, particularly in individuals with compromised immune systems. The immunopathogenesis of S. aureus infections involves intricate interactions with the host immune and non-immune cells, characterized by various virulence factors that facilitate adherence, invasion, and evasion of the host's defenses. This review highlights the complexity of S. aureus infections, ranging from mild to life-threatening conditions, and underscores the growing public health concern posed by multidrug-resistant strains, including methicillin-resistant S. aureus (MRSA). This article aims to provide an updated perspective on S. aureus-related infections, highlighting the main diseases linked to this pathogen, how the different cell types, virulence factors, and signaling molecules are involved in the immunopathogenesis, and the future perspectives to overcome the current challenges to treat the affected individuals.

Genomic epidemiology and phenotypic characterization of Staphylococcus aureus isolated from atopic dermatitis patients in South China

Atopic dermatitis (AD) is a multifactorial, chronic relapsing disease. Staphylococcus aureus is the key microbial factor in AD, linked to disease activity. However, there is limited knowledge of genomic prevalence characteristics and phenotypic features of S. aureus in AD patients in China. We investigated 108 S. aureus of AD in China and globally publicly available genome sequences of 579 S. aureus of AD. Sequence type (ST) 7, ST15 and ST188 were the major lineages in China. Genes esaC, esxB, and sea were only detected in ST7, potentially contributing to its prevalence in AD. ST188 exhibited high virulence and adhesion, possibly due to the cna gene. Phylogenetic and population structure analysis revealed that 579 strains of global AD were classified into 15 sequence clusters (SCs), with SC5, SC2, and SC7 dominating. S. aureus of Chinese AD patients was mainly distributed in SC2, SC7, and SC12. Comparative genomic highlighted genes linked to AD, including enterotoxins (seh, selk, selq, entH), adhesion genes (fnbA, fnbB, sdrD, map, fib, narH). From China and global perspectives, we analyzed S. aureus's genomic epidemic traits, phylogeny, and population structure in AD skin. These findings contribute to understanding S. aureus-host interactions and genomic diversity in AD.

Neutrophils in Atopic Dermatitis

Neutrophils have a critical role in inflammation. Recent studies have identified their distinctive presence in certain types of atopic dermatitis (AD), yet their exact function remains unclear. This review aims to compile studies elucidating the role of neutrophils in AD pathophysiology. Proteins released by neutrophils, including myeloperoxidase, elastase, and lipocalin, contribute to pruritus progression in AD. Neutrophilic oxidative stress and the formation of neutrophil extracellular traps may further worsen AD. Elevated neutrophil elastase and high-mobility group box 1 protein expression in AD patients' skin exacerbates epidermal barrier defects. Neutrophil-mast cell interactions in allergic inflammation steer the immunological response toward Th2 imbalance and activate the Th17 pathway, particularly in response to allergens or infections linked to AD. Notably, drugs alleviating pruritic symptoms in AD inhibit neutrophilic inflammation. In conclusion, these findings underscore that neutrophils may be therapeutic targets for AD symptoms, emphasizing their inclusion in AD treatment strategies.