Detection and antibiotic treatment of Herbaspirillum huttiense isolated from in vitro explants of Eucalyptus sp

In vitro assays involving explant cultures aiming the establishment of a genetic transformation protocol for the Eucalyptus grandis vs. E. smithii hybrid were hampered by the contamination of the explants. One yeast and one bacterium were isolated. The bacterium was identified as Herbaspirillum huttiense (Leifson) Ding and Yokota, with which further analyses were carried out and its response to different antibiotics were evaluated. Amongst 34 in vitro tested antibiotics, 12 inhibited bacterial growth. Sulfadiazine, streptomycin, kanamycin and penicillin were selected for determination of the minimal inhibitory concentration. Sulfadiazine, streptomycin and kanamycin presented inhibition halos at 256 and 512 mg L-1, while penicillin did not display bacteriostatic effects in concentrations up to 1024 mg L-1.