THE SOFT‐ROT BACTERIA OF THE COLI‐AEROGENES GROUP

Abstract

Summary:The indole, methyl‐red, Voges‐Proskauer and citrate reactions, and the pectate gel‐liquefying, gelatin‐liquefying and lactose‐fermenting properties of nineteen cultures of soft‐rot bacteria have been determined. The cultures included organisms labelled Bacterium carotovorum, Boat, aroideae and Bact. phytophthorum. Their M.R. and V.‐P. reactions and ability to grow in citrate medium are not constant within the group. It is recommended that these organisms should be grouped primarily on the exclusive characteristics of soft‐rot production and pectate gel liquefaction and that they should not be included in the classification of the coli‐aerogenes bacteria proposed by the Society for Applied Bacteriology except in the form of an appendix.Attention has been paid to a comparison of M.R. and V.‐P. reactions in O'Meara's fumarate medium and in the usual glucose‐phosphate broth. Though many more positive V.‐P. reactions are obtained in the fumarate medium, its exclusive use as a diagnostic test medium is not recommended, as it is so highly favourable to the accumulation of acetoin that it makes the test of less value as a means of differentiation.