Biochemical investigation of Providence strains and their relationship to theProteusgroup

Abstract

1. Seventy-four urease negative and twelve urease weakly positive strains were studied which, according to their biochemical properties, had to be considered as belonging to the Providence group. ThirtyProteus rettgeriand five anaerogenicProteusspecies were examined concomitantly.2. 668 strains of Enterobacteriaceae were tested for the P.P.A. reaction, of which only the 192Proteusand the 86 Providence strains rapidly transformed phenylalanine into phenylpyruvic acid.3. P.P.A. test, IMViC reactions, fermentation properties, smell, swarming are similar to those of theProteusgroup, particularlyP. rettgeri; it is therefore suggested that the Providence strains should be incorporated in theProteusgroup.4. For all purposes the P.P.A. reaction appears to be better suited than the urea test for differentiating strains of Enterobacteriaceae from theProteus-Providence group.The authors are grateful to Dr C. A. Stuart, Brown University, Providence, and Dr M. Greenstein, Sewage Disposal Works, Providence; to Dr W. H. Ewing, Communicable Disease Center, Chamblee, Georgia; to Prof. L. Olitzki, Hebrew University, Jerusalem; to Dr R. Mushin, University of Melbourne, Australia. We are especially indebted to Miss E. Salomon and Miss A. Engel for their valuable technical assistance.