Piscirickettsia salmonis (P. salmonis)

Piscirickettsia salmonis is a Gram-negative, facultative intracellular bacterium that is the causative agent of Salmonid Rickettsial Septicaemia (SRS), also known as Piscirickettsiosis (Fryer et al., 1992). This pathogen primarily targets salmonid fish species, including Atlantic salmon and Coho salmon, where it invades and replicates within host macrophages and monocyte-like cells (Mauel & Miller, 2002). The resulting systemic infection is characterized by severe tissue necrosis, internal hemorrhaging, and high mortality rates, making it one of the most significant economic threats to the global aquaculture industry (Rozas & Enríquez, 2014). P. salmonis utilizes a variety of virulence factors, including a Type IV secretion system (T4SS) and sophisticated iron uptake mechanisms, to subvert host immune responses and survive in the intracellular environment (Gómez et al., 2018). Treatment currently relies on the administration of antibiotics such as florfenicol and oxytetracycline, which inhibit bacterial protein synthesis, but the increasing prevalence of antibiotic-resistant strains has necessitated the search for novel therapeutic targets and more effective vaccines (Henríquez et al., 2016).

Other names

Salmonid Rickettsial Septicaemia agentSRS agentPiscirickettsiosis agent

Antibiotics targeting Piscirickettsia salmonis typically act by inhibiting bacterial protein synthesis through binding to the 30S or 50S ribosomal subunits, or by inhibiting DNA replication through the inhibition of DNA gyrase and topoisomerase IV (Henríquez et al., 2016; Rozas & Enríquez, 2014).