Characterization of Klebsiella granulomatis pathogenic to silkworm, Bombyx mori L.

Bacterial disease of silkworm causes significant reduction of silk production leading to huge economic loss. This study aims to isolate bacteria from diseased silkworm and to determine its pathogenicity and antibiotic resistance. A strain of Klebsiella granulomatis has been isolated from silkworm haemolymph which was later identified on the basis of biochemical tests and 16S rRNA gene sequencing. The optimum culture condition of K. granulomatis was determined at pH 7.0 and 37 °C temperature. The strain was resistant to most of the antibiotics used in this study except azithromycin, gentamycin and ciprofloxacin. The strain is capable to reproduce flacherrie like symptoms with high mortality rate when re-injected into healthy silkworm. Treatment with low dose of ciprofloxacin was found to be effective to prevent flacherrie induced by the isolated K. granulomatis strain.