Effectiveness of disinfectant treatments for inactivating Piscirickettsia salmonis

Abstract

This short communication investigated in vitro differences between commercial disinfectants types (n = 36), doses of application, and time of action in the elimination of Piscirickettsia salmonis, the most important bacterium affecting farmed salmon in Chile. Seven different treatments were examined, including active and inactive chlorine dioxides, glutaraldehyde, hypochlorite disinfectants and detergents, peracetic acid, peroxides and other miscellaneous methods A 3 replicate set of each of the sample groups was stored at 20 °C and 95% relative humidity and retested after 1, 5 and 30 min with varying doses (low, recommended and high doses). Multiple comparison tests were performed for the mean log CFU/ml among different disinfectant types, dose (ppm) and time of exposure (minutes) on the reduction of P. salmonis. Overall, disinfection using peracetic acid, peroxides, and both active and inactive chlorine dioxides caused significantly higher reduction of >7.5 log CFU/ml in samples, compared to other tested sanitizers. The lowest reduction was obtained after disinfection with hypochlorite detergents. As expected, as doses and time of action increase, there was a significant reduction of the overall counts of P. salmonis. However, at lowest doses, only use of paracetic acids resulted in zero counts. Implementation of effective protocols, making use of adequate disinfectants, may enhance biosecurity, and ultimately, mitigate the impact of P. salmonis in farmed salmon.

Assessing the toxicity of peracetic acid to early Atlantic salmon Salmo salar life‐stages

“…PAA has also been proven effective in reducing the parasitic theronts of Ichthyophthirius multifiliis that cause whitespot disease or "ich" in freshwater fish (Meinelt et al 2009;Straus and Meinelt 2009). When applied at 10 mg/L for 1 minute, PAA completely inactivated Piscirickettsia salmonis, the bacteria known to cause salmonid rickettsial septicemia (Muniesa et al 2019). Despite PAA's effectiveness in reducing pathogen loads, its use in RAS has proven to be safe for biofilter nitrifying bacteria colonies (Pedersen et al 2009).…”

Factors associated with severity of naturally occurring piscirickettsiosis in netpen‐ and tank‐reared juvenile Atlantic salmon at a research aquarium in western Canada

“…At the PBS aquarium, RSW is irradiated with UV at a wavelength of 265 nm and doses ranging from 317 to 721 mJ/cm 2 , well above doses known to inactivate a range of fish pathogenic bacteria (Bullock & Stuckey, ; Liltved, Hektoen, & Efraimsen, ). Inactivation studies of P. salmonis have focused on the application of disinfectants (Muniesa et al, ), and there are no published accounts of UV inactivation. Although more work is required to better establish dose and time parameters related to UV inactivation, the present study indicates the potential for treatment of sea water with UV as an aid in P. salmonis biosecurity.…”

Environmental issues in Chilean salmon farming: a review

“…Recently, Muniesa et al . () also showed that disinfection using peracetic acid, peroxides and both active and inactive chlorine dioxides is effective against P. salmonis .…”

“…Mardones et al (2016) found that the use of peracetic acid, peroxides, glutaraldehyde and active chlorine dioxide are the most effective for minimizing the load of Piscirickettsia salmonis contaminated on salmon fillets. Recently, Muniesa et al (2018) also showed that disinfection using peracetic acid, peroxides and both active and inactive chlorine dioxides is effective against P. salmonis.…”