Ten effective Isolates of R. legumiserum biovar phaseo/i (phaseoiqs vulgaris
L.) were isolated from 3 governorales of lower Egypt (Katr EI·Sheikh,
EI 8ehera and EI Gharbia ) at different locations during season (2002). AUlhe tesled
isolates gave positive results when su~Jected to purify tests. Screenin~ of the Isolates, using intrinsic anUbiotk. resistance (II\P.) melhod
against ampiCillin, kanamycin sulphate, rifampicin, streptomycin sulphate, neomycin,
dexacillln, erythromycin, terramycin, topramycin and colistin sulphate at 10 and high
concentration and showed variability to other antibiotics tested. On the basis of serological analysis, the representative isolates of IAR
groups are classified into four groups. Comparing IAR identificalion patterns of the
isolates, with serotyplng data. It was found that many lsoletes which showed similar
pattern to antibiotic resistance could be considered as one serotype. The representative strains were investigated for their symbiotic p rformance
under controUed conditions. Results showed that the obtained strains exerted different
responses in association with its specific host of p < /em>haseo/us vi/garis var. Gil .