Experimental pathogenesis and host immune responses of Enterococcus faecalis infection in Nile tilapia (Oreochromis niloticus)

Isolation and identification of Enterococcus faecalis from cultured Oreochromis niloticus and Mugil cephalus with a special emphasis on a possible integrated control strategy

“…amongst cultured freshwater and saltwater fish worldwide, particularly amongst species of tilapia (Rahman et al, 2017;Zahran et al, 2019). Our findings were in agreement with those reported by Zeid ( 2004) who described similar lesions in naturally and experimentally infected O. niloticus with Streptococcus sp.…”

“…MF 369837. Similar findings have been reported byZahran et al (2019) who noticed prominent signs of septicaemia and total mortalities up to 80% in O. niloticus experimentally challenged with E. faecalis that was genetically identified bySaad et al (2015). The developed lesions were attributed to the lethal and pestilent effect of bacterial extracellular enzymes and toxins, which undoubtedly promote cell necrosis and tissue damage(Ike, 2017;Kimura & Kusuda, 1979).…”

“…Deterioration of the physical or chemical properties of the water may adversely affect the host and support pathogen invasion (Rottmann et al, 1992). Enterococcal infection has been commonly reported amongst cultured freshwater and saltwater fish worldwide, particularly amongst species of tilapia (Rahman et al, 2017; Zahran et al, 2019). Our findings were in agreement with those reported by Zeid (2004) who described similar lesions in naturally and experimentally infected O. niloticus with Streptococcus sp.…”

“…Fish of the control group were injected intraperitoneally (IP) with 200 μl of sterile saline and served as a negative control, whereas fish of the challenged group were injected with 200 μl of an overnight culture of E. faecalis (ON845622) at an infectious dose of 7.5 log 10 CFU mL −1 (6.8 Log 10 CFU fish −1 ) as described by Zahran et al (2019). The inoculated fish were observed daily for 15 days post challenge for mortality and any clinical abnormalities or suspicious lesions.…”

“…Despite the low virulence of Enterococcus , accession of their infections to a serious extent and the presence of a high mortality rate gave a reasonable explanation for the increased awareness about the emergence of this bacterial agent (Thal et al, 1995). E. faecalis , an opportunistic pathogen, has been identified as the causative agent of haemorrhagic septicaemia that leads to mass mortality in several fish species (Rahman et al, 2017; Zahran et al, 2019).…”