OCCURRENCE AND PATHOGENICITY OF SERRATIA MARCESCENS AT FISH FARMS IN KAFR EL-SHEIKH GOVERNORATE

Document Type : Original Article

Authors

1 Poultry and Fish Dept., Fac. Vet. Med., Tanta Univ.

2 Pathology Dept. Fac. Vet. Med., Tanta Univ.

Abstract

Aninvestigationwascarriedoutfor unusual disease outbreaks occurred on 5 commercial oreochromis niloticus (O.niloticus) fish farms during the peroid 2003 – 2004 ,  in 3 Districts in Kafr El-Sheikh Governorate. Affected fish exhibited anorexia , sluggishness , variously sized areas of haemorrhage on the skin , corneal opacity and high mortality up to 21.4% . Bacterial isolates from the moribund fish were identified as Serratia marcescens (S.marcescens)by biochemical tests revealed 28 isolates. The virulence properties of this isolates , studied revealed that werehighlypathogenicfor fishwithLD50srangingfrom5x103to 1x105.  Moreover , the isolates were pathogenic for mice with LD50 1.6x106. Histopathological alterationsof the naturalandexperimental infections are described . The antibiogramme of the isolated S.marcescens was investigated .This study is considered the first record of S.marcescens infection in O.niloticus fish in Egypt .

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