DEOXYRIBONUCLEIC-ACID RELATEDNESS BETWEEN SERRATIA-PLYMUTHICA AND OTHER SERRATIA SPECIES, WITH A DESCRIPTION OF SERRATIA-ODORIFERA SP-NOV (TYPE STRAIN-ICPB 3995)

Seven new isolates of S. plymuthica (including two from a human source) and 24 isolates resembling unclustered Serratia strain 38 are described. Deoxyribonucleic acid relatedness studies, obtained with labeled reference deoxyribonucleic acid from S. plymuthica 392 confirm that S. plymuthica is a discrete species. Mean percent relatedness of S. plymuthica isolates to strain 392 was 88 ± 13.6 (standard deviation), whereas the mean percent relatedness of S. liquefaciens isolates (the closest species) to strain 392 was 52 ± 12.4. Strain 38 and twenty-four '38-like' isolates constitute a new deoxyribonucleic acid hybridization group that is 28 to 43% related to Serratia species and to the 'Citrobacter-like' group of Leclerc and Buttiaux, and 15 to 22% rleated to other known species of Enterobacteriaceae. This 38-like group constitutes a new species that is named Serratia odorifera sp. nov. (type strain, ICPB 3995). Two biotypes (1 and 2) are described. Strains of this species will grow on caprylate-thallous agar (selective for Serratia spp.), and they have a characteristic odor. Most strains of S. odorifera were recovered from clinical specimens.