Isolation and molecular characterization of some bacterial pathogens in El-Serw fish farm, Egypt

Abstract

The current study was carried out to isolate and identify some of bacteria infecting fish of El-Serw fish farm during the harvest season from December to March 2014-2015. Fish samples (155) were collected from different ponds of farm; 65 Nile tilapia (Oreochromis niloticus), 55 catfish (Clarias gariepinus) and 35 mullet (Liza ramada) were used to isolate bacteria in fish organs (gills, liver and kidney) using different selective media, from the examined fish, bacteria belonging to Pseudomonas, Aeromonas and Enterobacteriaceae were isolated. The group most frequently isolated from fish was Aeromonas, the highest number of putative Aeomonas isolates were obtained from O. niloticus 19 (29%), followed C. gariepinus 12 (21.8%) and L. ramada 5 (14.2%). Whereas putative Pseudomonas sp. showed fewer prevalence 9 (13.8%), 8 (14.5%) and 4 (11.4%) from O. niloticus, C. gariepinus and L. ramada, respectively, while only two colonies were recovered from Yersinia Agar Base. Seven isolates were selected and identified by sequencing of 16S rRNA. The analysis of sequence of 16S rRNA gene using universal primers (RW01 and DG74) resulted in the identification of three bacterial isolates of Pseudomonas fluorescens, one of Pseudomonas putida, two of Aeromonas hydrophila and one of Klebsiella oxytoca. The antibiogram test of these isolates revealed their sensitivity to ciprofloxacin, norfloxacin, and gentamycin.This study concluded that the performance 16S rRNA assay has the prospective to create an important contribution to infection management providing rapid of identification the bacterial pathogens in fish.

Molecular Studies on Aeromonas Species Isolated from Freshwater Fishes Collected from Delta Region, Egypt

“…The collected data showed that in some cases, congestion of gills and visceral organs, enlargement of liver, spleen, and kidney and in some cases paleness of liver and intestine were recorded. These results are in agreement with that formerly obtained in many studies (Parvez and Mudarris, 2014;El-Barbary and Hal, 2016;Elsayed et al, 2018;Elsheshtawy et al, 2019). Hemorrhagic septicemia was also reported in other studies in which relationship between stress factors and incidence of disease was revealed.…”

Synbiotic Effects of Saccharomycescerevisiae, Mannan Oligosaccharides, and β-Glucan on Innate Immunity, Antioxidant Status, and Disease Resistance of Nile Tilapia, Oreochromis niloticus

“…The light period was controlled automatically as 12 light hours: 12 h darkness in the laboratory. 2 Nitrogen free extract was determined by difference = 100-(protein % + fat % + crude fiber % + ash %). 3 Gross energy (GE) was calculated according to NRC [22] as 23.6 KJ/g protein, 39.5 KJ/g lipids and 17.0 KJ/g NFE.…”

“…Pseudomonas infection has been incriminated as one of the common bacterial infections of fishes and appears as an opportunistic and stress-related disease of freshwater fish cultured under intensive environments [ 2 ]. Motile Pseudomonas species are the most prevalent fish diseases in Egypt [ 3 ], causing septicemia, especially in Nile tilapia [ 2 ]. They are highly adaptable opportunistic bacteria that survive in different environments [ 4 ] and are responsible for the ulcerative syndrome of bacterial hemorrhagic septicemia, tail and fin rot, and ascites [ 2 ].…”

“…Motile Pseudomonas species are the most prevalent fish diseases in Egypt [ 3 ], causing septicemia, especially in Nile tilapia [ 2 ]. They are highly adaptable opportunistic bacteria that survive in different environments [ 4 ] and are responsible for the ulcerative syndrome of bacterial hemorrhagic septicemia, tail and fin rot, and ascites [ 2 ].…”

“…Fish diseases, especially those caused by bacterial pathogens, are important problems in the fish farm industry [1]. Pseudomonas infection has been incriminated as one of the common bacterial infections of fishes and appears as an opportunistic and stress-related disease of freshwater fish cultured under intensive environments [2]. Motile Pseudomonas species are the most prevalent fish diseases in Egypt [3], causing septicemia, especially in Nile tilapia [2].…”