Ananthan S, Dhamodaran S
Department of Microbiology, Post Graduate Institute of Basic Medical Sciences, University of Madras.
Indian J Med Res. 1996 Dec;104:336-41.
In a total of 720 faecal specimens from patients with secretory diarrhoea, vomiting, dehydration, gastroenteritis, cholera and cholera like illnesses, 18 strains of V. mimicus were isolated as pure culture. These were characterized for various toxin types and virulence factors using conventional in vitro and in vivo assays. Labile and stable toxins were elaborated by 15 and 2 strains respectively by ligated rabbit ileal loop (RIL) and suckling mouse assays. While 15 of the whole cell culture elaborated labile toxin, only 7 strains produced the same when culture filtrate was tested in RIL assay. Culture filtrates of 15 strains exhibited vascular permeability factor (PF) on adult rabbit skin, none of the strains were invasive as indicated by Sereny's test. Culture supernatants of all strains produced a cytotoxic factor to Vero and Chinese hamster ovary cells. Four of the 18 strains (22%) were resistant to multiple drugs (a combination of 3 or more drugs). The results emphasize the significance of continuous screening and identification of V. mimicus and to include in the differential diagnosis of patients with acute diarrhoea.
