Some biochemical characteristics of Vibrio fetus and other related Vibrios isolated from animals.

Microaerophilic, motile, gram-negative, comma-like bacteria have been found associated with the genital organs of the ovine and bovine species. These curved rods are believed to be an important cause of sterility in cows and sheep. Smith and Taylor (1919) proposed the name Vibrio fetus for these microorganisms. Recently, Brynei and Frank (1955) and Reich et al. (1956) found, using catalase and H2S activity as criteria, that organisms of the species V. fetus could be separated into two groups. The first group was catalase-positive and H2S-negative. This group was believed to be the true V. fetus and a pathogen. The second group contained the organisms that were catalase-negative and H2S-positive. They were thought of as saprophytes or nonpathogens belonging to a yet unnamed species. Similar vibiios have been isolated from cattle and calves with a diarrhea called winter scours and from pigs (Doyle, 1944) with a diarrhea called bloody dysentery. The vibrio of winter scours was named TVibrio jejuni by Jones et al. (1931). The organisms enumerated above are not only morphologically similar, but in addition, they are similar in that they lack fermentative powers (as measured by acid and gas production) (Plastridge, 1955). Since characteristics that are contingent on the ability of growing cultures to ferment substrates to acid and gas are lacking, other biochemical characteristics that might aid in classifying these vibrios were investigated. The approach taken was to study under standard conditions the oxidative capacity of resting vibrio cells (originating from different hosts and anatomical locations) towards a variety of sub-