Studies on Ulcerative Disease Caused by ProvidenciastuartiiBacteria in Indian Major Carp, Labeo rohita (Ham.)

Rohu (Labeo rohita) is a species of fish of the carp family cyprinidae. A survey was carried out from September, 2012 to August, 2013 to study the prevalence of bacterial ulcerative disease in L. rohita, cultivated in a freshwater farm located at Moongilthuraipattu Village of Villupuram District, Tamil Nadu, India. To mimic the infection in healthy fish, organs such as liver, gill and ulcerative skin were used to prepare the inoculum in PBS buffer. The inoculum was injected into healthy animals through intramuscular injection, immersion challenge and oral route. The tissue supernatant from infected rohu fish was screened for isolation and screening of the causative organism responsible for ulcerative lesion in L. rohita. Based on the biochemical, morphological and molecular features the bacterial culture isolated from infected rohu was tentatively identified as Providencia species like bacterium which was further confirmed by the analysis of its 16S rRNA gene using PCR and DNA sequencer and it has been identified as P. stuartii. Further, its partial sequence was deposited in GenBank (KF155520.1).