Journal of Environmental Biology

Lytic bacteriophages specific to Flavobacterium columnare rescue

catfish, Clarias batrachus (Linn.) from columnaris disease

Author Details

Yogendra Prasad

(Corresponding author)

Aquatic Biotechnology and Fish Pathology Laboratory, Department of Animal Science, M.J.P.

Rohilkhand University, Bareilly - 243 006, India

e-mail: yogendraps_2004@ yahoo.co.in

Arpana

Aquatic Biotechnology and Fish Pathology Laboratory, Department of Animal Science, M.J.P.

Rohilkhand University, Bareilly - 243 006, India

Dinesh Kumar

Aquatic Biotechnology and Fish Pathology Laboratory, Department of Animal Science, M.J.P.

Rohilkhand University, Bareilly - 243 006, India

A.K. Sharma

Aquatic Biotechnology and Fish Pathology Laboratory, Department of Animal Science, M.J.P.

Rohilkhand University, Bareilly - 243 006, India

Publication Data

Paper received:

30 December 2009

Revised received:

15 May 2010

Accepted:

10 June 2010

Abstract

This investigation was aimed to find out appropriate strategy against antibiotic resistant bacterial fish pathogen, F. columnare. This pathogen was found persistently associated with fishes causing columnaris disease and ensuing mass mortality in hatchery and culture system of Sub - Himalayan region. Nine lytic F. columnare phages (FCP1 ? FCP9) specific to its fifteen isolates were isolated from the water and bottom sediments of various geo-climatic regions of North India. The F. columnare phage FCP1 (made of hexagonal head and non contractile long tail belonging to family Podovariedae, a member of DNA virus) exhibited broader host range to lyse 9 out of 15 isolates of F. columnare. Therapeutic ability of FCP1 phage was assessed in C. batrachus inoculated intramuscularly (im) with virulent bacterial isolate FC8 and post inoculated (PI) with FCP1phage (@ 10⁸ : 10⁶ :: cfu : pfu) through intramuscular (im), immersion (bath) and oral (phage impregnated feed) treatment. Significant (p<0.001) reduction (less than 10^-3 cfu ml^-1) in host bacterium in the sera, gill, liver and kidney of challenged fishes was noted after 6 hr of phage treatment. Quantum of phage played? a significant role in bringing down bacterial population as in the sera of dose 1 (@ 4.55 X 10⁶ pfu ml^-1)? and dose 2 (@ 9.15 X 10⁶ pfu ml^-1)? treated fishes mean log₁₀ cfu value reduced by 3 logs (58.39%) and 5 logs (73.77%) at 96 hr, respectively. Phage treatment led to disappearance of gross symptoms, negative bacteriological test, detectable phage and 100% survival in experimentally infected C. batrachus. Result of this study provides evidence of profound lytic impact of FCP1 phage and represents its interesting therapeutic importance against antibiotic resistant F. columnare.

Key words

Bacteriophage, C. batrachus, Columnaris disease, Flavobacterium columnare

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