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Legionella pneumophila is an intracellular bacterial pathogen that can cause a severe form of pneumonia in humans, a phenotype evolved through interactions with aquatic protozoa in the environment. Here, we show that L. pneumophila uses extracellular vesicles to translocate bacterial small RNAs (sRNAs) into host cells that act on host defence signalling pathways. The bacterial sRNA RsmY binds to the UTR of ddx58 (RIG-I encoding gene) and cRel, while tRNA-Phe binds ddx58 and irak1 collectively reducing expression of RIG-I, IRAK1 and cRel, with subsequent downregulation of IFN-β. Thus, RsmY and tRNA-Phe are bacterial trans-kingdom regulatory RNAs downregulating selected sensor and regulator proteins of the host cell innate immune response. This miRNA-like regulation of the expression of key sensors and regulators of immunity is a feature of L. pneumophila host-pathogen communication and likely represents a general mechanism employed by bacteria that interact with eukaryotic hosts.
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http://dx.doi.org/10.1038/s41467-022-28454-x | DOI Listing |
Appl Environ Microbiol
September 2025
Department of Environmental Microbiology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland.
Unlabelled: The genus includes opportunistic pathogens inhabiting engineered aquatic ecosystems, where managing their presence and abundance is crucial for public health. In these environments, interact positively or negatively with multiple members of the microbial communities. Here, we identified bacteria and compounds with -antagonistic properties.
View Article and Find Full Text PDFLancet Rheumatol
September 2025
Service de Médecine interne et polyvalente, Centre Hospitalier du Haut-Anjou, Château-Gontier, France; Université d'Angers, Inserm, CNRS, MITOVASC, Equipe MitoLab, SFR ICAT, F-49000 Angers, France. Electronic address:
Infections are increasingly recognised as a major cause of morbidity and mortality in patients with vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic (VEXAS) syndrome. We conducted a systematic review to characterise the infectious burden of VEXAS syndrome and propose preventive strategies. We included 57 studies (813 patients) showing that infections in patients with VEXAS syndrome were frequent, severe in 40-60% of cases, and fatal in 6-15% of cases.
View Article and Find Full Text PDFMicrob Genom
September 2025
New Zealand Institute for Public Health and Forensic Science, Porirua, New Zealand.
is a pathogen of global health importance due to its role in causing Legionnaires' disease (LD), a severe form of community-acquired pneumonia. Throughout the USA and Europe, is often identified as the primary cause of LD, but in countries such as New Zealand and Australia, where testing for non- species is employed systematically, high rates of are reported. Development of genomic tools to track outbreaks and identify infection sources for has lagged behind that of .
View Article and Find Full Text PDFJ Infect Dis
September 2025
Institute for Biomedicine and Glycomics, Griffith University, Southport, QLD, Australia.
Background: In 2021-2022, Queensland, Australia observed an increase in Legionnaire's disease cases, predominantly due to Legionella longbeachae. This study assessed seroprevalence at time points 2016 and 2023, representing before and after the higher incidence and explored if demographic, environmental and geographical factors associated with legionellosis seroprevalence.
Methods: A total of 1001 human plasma samples (496 from 2016/505 from 2023) were analysed for the presence of Legionella antibodies (IgG) using indirect immunofluorescence assays.
Sci Adv
September 2025
Department of Biochemistry, University of Toronto, 661 University Ave., Toronto, Ontario M5G 1M1, Canada.
Host cells provide intracellular bacteria with protection from harsh environmental conditions and immune responses, but for many intracellular pathogens, this protection does not appear to be absolute as once thought. Bacteriophages that can kill bacteria inside host cells have been identified for pathogens including , , and species. Even in pathogens for which no stable phages have been isolated, such as , the presence of phage defense systems suggests phage susceptibility.
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