Roles of water quality and disinfectant application on inactivation of fish pathogenic Streptococcus agalactiae with povidone iodine, quaternary ammonium compounds and glutaraldehyde

Abstract

Streptococcosis is an important bacterial disease in Nile tilapia causing severe economic losses to tilapia aquaculture worldwide. The effects of water quality (low- [LS] and high-level [HS] soiling, to mimic clean or dirty surface conditions and temperatures) and disinfectant application (diluted concentrations and exposure time) were characterized on the inactivation of Streptococcus agalactiae isolated from diseased tilapia. Five isolates were tested against three commercial disinfectant products with the main ingredients being povidone iodine (Anidine 100™; AD), benzalkonium chloride (Better BKC 80%™; BKC 80), and a mixture of quaternary ammonium compounds and glutaraldehyde (Chloraldehyde™; CR). CR demonstrated highest efficacy to S. agalactiae inactivation, followed by BKC 80 and AD, respectively. Higher-level soiling, low temperature, diluted concentrations and short exposure time all decreased the disinfectant efficacy. CR and BKC 80 provided more than 5-log inactivation at 1-min exposure at 20°C under HS conditions, and also with ten-fold-diluted concentrations at 60-min exposure time at 30°C. However, AD required 10-min exposure to effectively remove bacteria under LS conditions at 30°C. The results could facilitate aquaculture management planning that leads to operating cost reductions and improvements in biosecurity.

Virucidal effects of common disinfectants against tilapia lake virus

“…Another issue to take into consideration when using these disinfectants in such conditions is increasing concentration or contact time. In a previous study, iodine, benzalkonium chloride and glutaraldehyde significantly reduced the bacterial load of pathogenic S. agalactiae, isolated from moribund tilapia in Thailand (Mon-On, Surachetpong, Mongkolsuk, & Sirikanchana, 2018). Because many types of disinfectants have a broad effect on both viruses and pathogens (including bacteria and parasites), application of these disinfectants can help control multiple pathogens simultaneously.…”

Comprehensive toxic effects of povidone iodine on microalgae Chlorella pyrenoidosa under different concentrations

“…PVP‐I‐based products could play an important role in the fight against COVID‐19 because of its rapid and effective virucidal activity to wipe out SARS‐CoV‐2 (Anderson et al, 2020). It could effectively kill bacteria in aquaculture such as Streptococcosis in Neil tilapia and Aeromonas hydrophila in swamp eel (Mon‐On et al, 2018; Xuan et al, 2018). In aquatic animal virus, PVP‐I can kill Tilapia Lake Virus and inactivate white spot syndrome virus in the concentration of 100 ppm (Chang et al, 1998; Soto et al, 2019).…”

Intragastric and intracoelomic injection challenge models of tilapia lake virus infection in Nile tilapia (Oreochromis niloticus L.) fingerlings

“…Aquaculture of tilapia species is an important source of protein for many people. However, intensification of aquaculture practices has resulted in an increase in the incidence and severity of infectious diseases (Colquhoun & Duodu, ; Mon‐On, Surachetpong, Mongkolsuk, & Sirikanchana, ). Emerging and re‐emerging infectious diseases such as piscine francisellosis, streptococcosis and tilapia lake virus infections pose significant threats to tilapia aquaculture, resulting in significant economic deficits not only from direct losses associated with mortality, but in the form of lost feed days and costly chemotherapeutics (Colquhoun & Duodu, ; Eyngor et al, ; Krkosek, Lewis, Morton, Frazer, & Volpe, ; Lafferty, Porter, & Ford, ; Shoemaker, Xu, & Soto, ).…”