International Journal of Fisheries and Aquatic Studies
2018, Vol. 6, Issue 2, Part A
Phenotypic and molecular characterization of bacterial pathogens isolated from diseased freshwater fishes
Author(s): Aya F Matter, Amel M El Asely, Adel A Shaheen, Eman A Abd El-Gawad, Hiam El-Abd and Amany A Abbass
Abstract: Clinically diseased
Oreochromis niloticus,
Claris gariepinus, and
Mugil cephalus were collected from different localities at El – Riah El- Tawfiki and its tributaries (Qalyubia), Kafr El-Sheik and Ismailia governorates. The clinical picture and gross lesions were recorded. Isolation and identification of the bacterial pathogens using traditional and molecular methods were demonstrated. It was found that the diseased fishes were showing general septicemic signs as skin hemorrhages and ulcerations, uni- and bilateral exophthalmia, congested internal organs with significant mortalities. Additionally, the total prevalence of the retrieved bacterial isolates was (55.27%) among the species and it was 62.5, 45, and 32.5 % in
O. niloticus,
C. gariepinus, and
M. cephalus respectively. Summer season displayed the highest prevalence in the examined fishes. Based on the phenotypic and biochemical characterization using API20E, the isolated bacteria were identified as
Aeromonads (
A. hydrophila, A. veronii, A. caviae and
A. sobria),
Pseudomonas spp (
Ps. fluorescence, Ps. aeroginosa, and
Ps. putida),
Citrobacter spp (
C. koseri, C. freundii, and
C. braakii),
Serratia spp (
S. odorifera, S. liquefaciens, and
S. marcescens),
Enterobacter spp (
E. sakazakiiand
E. cloacae) and
Vibrio fluialis.
O. niloticus was the most infected fish species followed by
C. gariepinus and
M. cephalus. Almost all the detected bacterial isolates were isolated from kidneys and liver samples. The most prevalent bacterial isolates were
Aeromonads (12 isolates, 48%), among them;
A. hydrophila was the predominant species (5 isolates, 20%), and followed by
A. veronii (3 isolates, 12%),
A. sobria (3 isolates, 12%) and
A. caviae (1 isolate, 4%). Molecular characterization using conventional PCR to confirm the biochemically identified
Aeromonads using the16S rDNA region retrieved band at 900 bp. Together, these results suggest that several septicemic bacterial pathologies were widespread in the freshwater fishes, where their presence may lead to mortality.
Pages: 34-41 | 1740 Views 549 DownloadsDownload Full Article: Click Here
How to cite this article:
Aya F Matter, Amel M El Asely, Adel A Shaheen, Eman A Abd El-Gawad, Hiam El-Abd, Amany A Abbass. Phenotypic and molecular characterization of bacterial pathogens isolated from diseased freshwater fishes. Int J Fish Aquat Stud 2018;6(2):34-41.
