Piscirickettsiaceae

Piscirickettsiaceae is a family of Gram-negative, intracellular bacteria that are primarily known for causing disease in fish. The family currently consists of a single genus, Piscirickettsia, which includes the species Piscirickettsia salmonis, a significant pathogen of salmonid fish.

Taxonomy

The family Piscirickettsiaceae is part of the order Thiotrichales in the class Gammaproteobacteria. It currently contains only one genus, Piscirickettsia, with Piscirickettsia salmonis being the only species in this genus.

Characteristics

Members of the Piscirickettsiaceae are Gram-negative, non-motile, and obligate intracellular bacteria. They are coccobacilli in shape and are typically 0.5-1.5 µm in diameter. They are capable of surviving and replicating within the phagosome of host cells, a trait that contributes to their pathogenicity.

Pathogenicity

Piscirickettsia salmonis, the only known species in the Piscirickettsiaceae, is a significant pathogen of salmonid fish. It is the causative agent of salmonid rickettsial septicemia (SRS), a severe systemic disease that can result in high mortality rates in affected populations. SRS is considered one of the most significant health problems in the salmon farming industry, particularly in Chile, where it has caused significant economic losses.

Treatment and Control

Control of P. salmonis infections in aquaculture settings typically involves a combination of vaccination, improved management practices, and the use of antibiotics. However, the development of antibiotic resistance in P. salmonis is a growing concern, highlighting the need for continued research into alternative control strategies.

See Also

• Rickettsiales
• Aquaculture
• Fish diseases