The emergence and spread of antibiotic resistance pose serious environmental and health challenges. Attention has been drawn to phage therapy as an alternative approach to combat antibiotic resistance with immense potential. However, one of the obstacles to phage therapy is phage resistance, and it can be acquired through genetic mutations, followed by consequences of phenotypic variations. Therefore, understanding the mechanisms underlying phage-host interactions will provide us with greater detail on how to optimize phage therapy. In this study, three lytic phages (phipa2, phipa4, and phipa10) were isolated to investigate phage resistance and the potential fitness trade-offs in Pseudomonas aeruginosa. Specifically, in phage-resistant mutants phipa2-R and phipa4-R, mutations in conferring resistance occurred in genes pilT and pilB, both essential for type IV pili (T4P) biosynthesis. In the phage-resistant mutant phipa10-R, a large chromosomal deletion of ~294 kb, including the hmgA (homogentisate 1,2-dioxygenase) and galU (UTP-glucose-1-phosphate uridylyltransferase) genes, was observed and conferred phage phipa10 resistance. Further, we show examples of associated trade-offs in these phage-resistant mutations, e.g., impaired motility, reduced biofilm formation, and increased antibiotic susceptibility. Collectively, our study sheds light on resistance-mediated genetic mutations and their pleiotropic phenotypes, further emphasizing the impressive complexity and diversity of phage-host interactions and the challenges they pose when controlling bacterial diseases in this important pathogen. IMPORTANCE Battling phage resistance is one of the main challenges faced by phage therapy. To overcome this challenge, detailed information about the mechanisms of phage-host interactions is required to understand the bacterial evolutionary processes. In this study, we identified mutations in key steps of type IV pili (T4P) and O-antigen biosynthesis leading to phage resistance and provided new evidence on how phage predation contributed toward host phenotypes and fitness variations. Together, our results add further fundamental knowledge on phage-host interactions and how they regulate different aspects of Pseudomonas cell behaviors.

Asthma is prone to Th2-mediated chronic airway inflammation. Interleukin-27 (IL-27) is a member of the IL-12 family that promotes the differentiation of Th1 cells and inhibits Th2 cells. We use human/mouse CD4+ T cells to see whether IL-27 could inhibit IL-4 production in vitro and then observe whether IL-27 administration could alleviate allergic airway inflammation in vivo by mice asthma model.

Epidemiological studies have shown that urban particulate matter (PM) increases the risk of respiratory infection. However, the underlying mechanisms are poorly understood. PM has been postulated to suppress the activation of airway epithelial innate defence in response to infection.

Metagenomic next-generation sequencing (mNGS) is widely applied in the etiological diagnosis of infectious diseases. However, the clinical practice of mNGS in infective endocarditis (IE) is relatively less studied. This research aimed to assess the etiological diagnostic value of valve mNGS in IE.

To evaluate the diagnostic accuracy of metagenomic next-generation sequencing (mNGS) for active tuberculosis (TB).

FGF-10 can prevent or reduce lung specific inflammation due to traumatic or infectious lung injury. However, the exact mechanisms are poorly characterized. Additionally, the effect of FGF-10 on lung-resident mesenchymal stem cells (LR-MSCs) has not been studied. To better characterize the effect of FGF-10 on LR-MSCs, FGF-10 was intratracheally delivered into the lungs of rats. Three days after instillation, bronchoalveolar lavage was performed and plastic-adherent cells were cultured, characterized and then delivered therapeutically to rats after LPS intratracheal instillation. Immunophenotyping analysis of FGF-10 mobilized and cultured cells revealed expression of the MSC markers CD29, CD73, CD90, and CD105, and the absence of the hematopoietic lineage markers CD34 and CD45. Multipotency of these cells was demonstrated by their capacity to differentiate into osteocytes, adipocytes, and chondrocytes. Delivery of LR-MSCs into the lungs after LPS injury reduced the inflammatory response as evidenced by decreased wet-to-dry ratio, reduced neutrophil and leukocyte recruitment and decreased inflammatory cytokines compared to control rats. Lastly, direct delivery of FGF-10 in the lungs of rats led to an increase of LR-MSCs in the treated lungs, suggesting that the protective effect of FGF-10 might be mediated, in part, by the mobilization of LR-MSCs in lungs.