The inhibitory effects of disinfectants against Aeromonas salmonicida at low temperatures

Abstract

Aeromonas salmonicida is a fish pathogen that has resulted in significant losses to the aquaculture industry worldwide. In the winter of 2018/2019, a serious outbreak of A. salmonicida infection of grass carp (Ctenopharyngodon idella) occurred in China. Since C. idella do not feed at low water temperatures, antibiotics cannot be delivered orally, thus the use of disinfectants is the only viable option to control the disease in the winter months. Therefore, the aim of this study was to elucidate the inhibitory effects of different disinfectants against A. salmonicida at various temperatures and pH values. The microdilution method was used to determine the minimum inhibitory concentration (MIC) of five disinfectants against A. salmonicida at different temperatures. The results showed that A. salmonicida was highly adaptable to temperatures ranging from 8 to 35 °C and pH values from 5 to 9. Moreover, based on the results, benzalkonium bromide (BB) had the strongest inhibitory effect at every temperature. Since A. salmonicida has strong environment adaptability, BB should be chosen to control the disease at low temperatures.