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Process for preparation of improved mutant strain of Bordetella bronchiseptica useful for live attenuated vaccine for protection of B. bronchiseptica infection and live attenuated AR vaccine produced therefrom
Process for preparation of improved mutant strain of Bordetella bronchiseptica useful for live attenuated vaccine for protection of B. bronchiseptica infection and live attenuated AR vaccine produced therefrom
A process for the preparation of a mutant strain of B. bronchiseptica having chromosomal genetic markers carrying at least temperature- sensitive (grown at 42° C.), nalidixic acid-resistant and heat- labile dermonecrotic toxin producing ability negative markers, suitable for the preparation of live attenuated AR vaccine, which comprises subjecting a strain of B. bronchiseptica to an induced mutation, isolating a mutant having the genetic markers of being at least temperature-sensitive (grown at 42° C.), nalidixic acid-resistant and heat-labile dermonecrotic toxin negative, culturing the isolated strain of B. bronchiseptica on a Bordet-gengou agar plate containing nalidixic acid at 42° C., thereafter picking up an organism morphologically resembling a phase-I organism, repeating the procedures of culturing and picking up, and converting the organisms to a heat- labile dermonecrotic toxin-producing ability negative phase-I organism having a complete capsular antigen.
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