Type III secretion system effectors form robust and flexible intracellular virulence networks
Infections with many Gram-negative pathogens, including Escherichia coli, Salmonella, Shigella, and Yersinia, rely on type III secretion system (T3SS) effectors. We hypothesized that while hijacking processes within mammalian cells, the effectors operate as a robust network that can tolerate substantial contractions. This was tested in vivo using the mouse pathogen Citrobacter rodentium (encoding 31 effectors). Sequential gene deletions showed that effector essentiality for infection was context dependent and that the network could tolerate 60% contraction while maintaining pathogenicity. Despite inducing very different colonic cytokine profiles (e.g., interleukin-22, interleukin-17, interferon-, or granulocyte-macrophage colony-stimulating factor), different networks induced protective immunity. Using data from>100 distinct mutant combinations, we built and trained a machine learning model able to predict colonization outcomes, which were confirmed experimentally. Furthermore, reproducing the human-restricted enteropathogenic E. coli effector repertoire in C. rodentium was not sufficient for efficient colonization, which implicates effector networks in host adaptation. These results unveil the extreme robustness of both T3SS effector networks and host responses.
ConclusionsBoth QGI and NGE testing panels can improve laboratory workflow and patient management by providing user-friendly platforms that can rapidly detect a number of targets with one specimen. QGI was significantly more sensitive in identifyingC. difficile. Both methods had suboptimal detection ofSalmonella and this needs to be examined further. The short hands-on time and turnaround time are of value for on-demand testing and use in a high-throughput setting.
Dermatol Online J. 2021 Jul 15;27(7). doi: 10.5070/D327754373.ABSTRACTReactive arthritis is an extremely rare spondyloarthritis that affects the peripheral joints and spine, resulting in common symptoms such as arthritis, urethritis, conjunctivitis, and mucocutaneous lesions. On rare occasions, oral lesions such as circinate erosions on the hard and soft palate, gums, tongue, and cheeks may occur. Reactive arthritis may develop during or after genitourinary or gastrointestinal bacterial infections such as Shigella, Salmonella, Yersinia, and Chlamydia. A 36-year-old man presented with circinate balanitis, urethral discharge...