Rhizobium radiobacter (syn. Agrobacterium radiobacter) is a saprophytic,
gram negative rod belonging to alpha proteobacteria, family
Rhizobiaceae. Agrobacterium and Rhizobium are highly related and their
species are interwoven. Agrobacterium species have been reclassified in
the genus Rhizobium, based on 16S rRNA homology amalgamating the
pathogenic, symbiotic nitrogen-fixing and non-pathogenic species in a
generic circumscription of Rhizobium (Young et al., 2001). Agrobacterium
tumefaciens (syn. Agrobacterium radiobacter) was conserved as the type
species of Agrobacterium, but the epithet radiobacter took precedence as
Rhizobium radiobacter in the revised genus. Agrobacterium (Rhizobium)
radiobacter does not contain the Ti plasmid associated with tumour
induction in plants (Sawada et al., 1993). Rhizobium radiobacter is a fast
growing, keto-lactose negative, reported as a plant growth promoting
bacteria and to infect soybean and has been isolated from its root nodules
(Ansari et al 2014). Plant-pathogenic, soil inhabitant R. radiobacter is
not characterized as a true human pathogen but as an opportunistic human
pathogen. Human infections caused by R. radiobacter that are reported
include catheter-related bacteraemia, endocarditis, continuous ambulatory
peritoneal dialysis peritonitis, urinary tract infections, pneumonia and
chronic endopthalmitis.
