Members of the genus Aeromonas are ubiquitous bacteria that are generally associated with aquatic environments and form long-term mutualistic relationships in the gastrointestinal tract of fish and leeches.
However, they are also important fish pathogens that cause significant economic losses in aquaculture. In addition, Aeromonas species are increasingly recognized as opportunistic pathogens in humans, causing a plethora of symptoms ranging from mild gastroenteritis to severe necrotic fasciitis or septicemia in immunocompromised individuals.
Virulence factors include ability to form biofilm, structural components such as flagella, pili, and capsules, as well as a variety of secreted toxins and enzymes that impair host defense. Among these, the type III secretion system (T3SS) and its effector proteins play a central role in the virulence of several Aeromonas species.
Visualization of the architecture and composition of the biofilm formed by A. schubertii ATCC 43700, which is an emerging aquatic pathogen in South East Asia.
Aeromonas schubertii causes high mortality in snakehead fish. In this study, we demonstrate that the T3SS injectisome, encoded within API1, is an important cytotoxicity determinant. We further identified novel T3SS effectors and their distinct contributions to host cell cytotoxicity, including the pro-survival effect of AopI and the cytotoxic effect of AopL. This interplay highlights a fine-tuned balance between pro-survival and cytotoxic mechanisms which is orchestrated by A. schubertii effectors.
Michova H, Pliva J, Jirsova A, Jurnecka D, and Kamanova J.* (2025): Cytotoxicity induced by Aeromonas schubertii is orchestrated by a unique set of type III secretion system effectors. Veterinary Research, https://doi.org/10.1186/s13567-025-01548-2. This work was funded by a grant from the Programme Johannes Amos Comenius under the Ministry of Education, Youth and Sports of the Czech Republic (project Nr CZ.02.01.01/00/22_008/0004597), and the Lumina Queruntur Fellowship LQ200202001 of the Czech Academy of Sciences.