<Tr> <Th_colspan="2"> Binomial name </Th> </Tr> <Tr> <Td_colspan="2"> Vibrio cholerae Pacini 1854 </Td> </Tr> <P> Vibrio cholerae is a Gram - negative, comma - shaped bacterium . The bacterium's natural habitat is brackish or saltwater . Some strains of V. cholerae cause the disease cholera . V. cholerae is a facultative aerobe and has a flagellum at one cell pole as well as pili . V. cholerae can undergo respiratory and fermentative metabolism . When ingested, V. cholerae can cause diarrhoea and vomiting in a host within several hours to 2--3 days of ingestion . V. cholerae was first isolated as the cause of cholera by Italian anatomist Filippo Pacini in 1854, but his discovery was not widely known until Robert Koch, working independently 30 years later, publicized the knowledge and the means of fighting the disease . </P> <P> V. cholerae is Gram - negative and comma - shaped . Initial isolates are slightly curved, whereas they can appear as straight rods upon laboratory culturing . The bacterium has a flagellum at one cell pole as well as pili . V. cholerae is a facultative anaerobe, and can undergo respiratory and fermentative metabolism . </P>

Briefly describe the shape of the bacterium that causes cholera