Bright Singh, I S; Rosamma, Philip; Rejish Kumar, V J; Jayaprakash, N S(Blackwell Publishing Ltd, March 1, 2006)
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Abstract:
Surveys for bacteriological analysis of larval samples
to isolate the associated vibrios were carried out during
1985^1992, 2001 and 2002 in three di¡erent
hatcheries located on the southwest coast of India.
Vibrio isolates were examined for their species diversity,
virulence based on haemolysis in prawn blood
agar, lipolysis, proteolysis and chitinolysis and antibiotic
sensitivity.Vibrio cholerae was the predominant
species in the apparently healthy larval samples,
whereas V. alginolyticus and V. vulni¢cus dominated
during disease and morbidity. No correlation was
found between the hydrolytic properties and haemolytic
activity of the vibrios associated with the larvae.
All isolates were resistant to erythromycin and resistance
to oxytetracycline, ampicillin and streptomycin
sulphate was prevalent among the larger section of
the Vibrio population. This suggested that antibiotic
application may not be of much use to protect the larvae
fromvibriosis. This is the ¢rst report on the diversity
of Vibrio species associated with Macrobrachium
rosenbergii larvae and their virulence characteristics
based on haemolysis in prawn blood agar