Despite being considered a normal flora, can cause diarrhea. In a previous study, strain 2939/90, obtained from a diarrheal patient, caused invasion and actin condensation in mammalian cells, and diarrhea in a rabbit model. Four Tn mutants of 2939/90 produced negligible invasion and actin condensation in mammalian cells. Now, the parent strain and the mutants have been sequenced to locate Tn insertion sites and determine the effect on virulence. A Tn insertion was detected in the type three secretion system (T3SS) locus on a large plasmid and not in a T3SS locus on the chromosome. In 52 genomes of surveyed, the chromosomal T3SS locus was present in all strains, including both genomic clades, which we classified as group A and group B. Plasmid T3SS was present in 21 of 52 genomes, mostly in group A genomes, which included isolates from an outbreak of hemorrhagic diarrhea in dogs. The Tn insertion only in the plasmid T3SS locus affected the invasion phenotype, suggested that this locus is critical for causation of diarrhea. We conclude that a subgroup of that possesses this plasmid-mediated T3SS is an enteric pathogen that can cause diarrheal disease.
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http://dx.doi.org/10.3390/microorganisms12071479 | DOI Listing |
J Med Microbiol
October 2024
Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mor., Mexico.
Enteropathogenic (EPEC) strains pose a significant threat as a leading cause of severe childhood diarrhoea in developing nations. EPEC pathogenicity relies on the type III secretion system (T3SS) encoded by the locus of enterocyte effacement (LEE), facilitating the secretion and translocation of bacterial effector proteins. While the regulatory roles of PerC (plasmid-encoded regulator) and GrlA (global regulator of LEE-activator) in expression and LEE gene activation are well-documented in the EPEC prototype strain E2348/69, understanding the variability in LEE gene expression control mechanisms among clinical EPEC isolates remains an area requiring further investigation.
View Article and Find Full Text PDFMicroorganisms
July 2024
Department of Microbiology, College of Medicine, Kuwait University, Jabriya P.O. Box 24923, Kuwait.
bioRxiv
February 2024
Disciplina de Microbiologia, Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, São Paulo, Brazil.
Newborn (Clarksville)
April 2023
Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois; Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois, United States of America.
Enteropathogenic (EPEC) are important diarrheal pathogens of infants and young children. Since the availability of molecular diagnosis methods, we now have new insights into the incidence and prevalence of these infections. Recent epidemiological studies indicate that atypical EPEC (aEPEC) are seen more frequently than typical EPEC (tEPEC) worldwide, including in both endemic diarrhea and diarrhea outbreaks.
View Article and Find Full Text PDFNat Commun
April 2023
Department of Physics, Ben Gurion University of the Negev, Beer Sheva, Israel.
The type three secretion system (T3SS) is a membrane-anchored nano-machine utilized by many pathogenic bacteria to inject effector proteins and thus take control of host cells. In a recent article, Kaval et al. reveal a striking colocalization of a T3SS-encoding locus, its transcriptional activators, protein products, and the complete structure at the cell membrane, which they claim provides evidence for a mechanism known as ‘transertion’.
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