Oreochromis niloticus from Qaroun and El Rayan lakes were collected and examined for the presence
of pseudomonas species. The organisms were found in 30.83% of the 480 examined fish with some fish,
especially during the episode of mass mortality showing, typical signs of pseudomonas septicemia; redness
all over the body, abdominal swelling, eyes cloudness, scales detachment and congested gills. Culture from
liver, spleen, kidneys and gills on pseudomonas agar media yielded different species of pseudomonas with
morphological and biochemical characters identical to P. fluorescens biovar I, II, III, P. anguilliseptica, P.
putida and P. aureginosa isolated from the same fish and other fish species of Qaroun and El Rayan lakes as
well as for those recovered from other kinds of fish. The prevalence of infection revealed significant difference
among four batches, it was 43.33% (April 2008), 24.44% (August 2008), 21.11% (November 2008) and 17.77%
(January 2009); and the organisms were mainly isolated from liver and kidney (35 and 30%, respectively).
Challenge tests revealed that P. angulliseptica was the highest pathogenic one and induced 96.66% mortality,
while P. fluroscens injected groups showed 2% mortality. Antibiogram sensituity revealed high sensitivity to
Avatryl and Amikicin and sensitivity to Gentamicin, Erythromycin, Novobiocin and Sulfa-trimethoprime. Three
major proteins of 29 KDa, 30 KDa and 35 KDa in the whole cell proteins of pseudomonas strains. The
pathogenic strains P. aeruginosa, P. putida and P. angulliseptica had 9-11 protein bands ranged from 23.4 to
100.05 KDa in molecular weight, while non-pathogenic strains; P. fluroscens biovar I, II and III showed 7-9
protein bands and of molecular weight ranged from 22 to 87 KDa. It was concluded that different pseudomonas
diseases were considered Qaroun and El-Rayan lakes causes septicemia in O. niloticus and the pathogenic
species include P. anguilliseptica, P. putida and P. aureginosa. Avatryl and Amikicin are the best drug for
treatment of septicemia caused by the above mentioned species in O. niloticus. |
