Providencia alcalifaciens: a Causal Agent of Red Leg Disease in Freshwater-Cultured Whiteleg Shrimp Penaeus vannamei

Abstract

Red leg disease causes significant economic losses in whiteleg shrimp Penaeus vannamei. Yet only scarce information is available on Providencia alcalifaciens as a bacterial pathogen of this disease. In this study, a virulent strain, temporarily named P3, was isolated from diseased freshwater-cultured P. vannamei suffering from red leg disease, identified phenotypically and molecularly as P. alcalifaciens. A phylogenetic tree was constructed to examine the taxonomic position and relatedness of isolate P3 to other P. alcalifaciens isolates. When screened against a range of common veterinary antibiotics, isolate P3 exhibited susceptibility to aminoglycosides and quinolones antibiotics in aquaculture. To the best of our knowledge, this is the first report of P. alcalifaciens as a causal agent of red leg disease in freshwater-cultured P. vannamei.