Cultivation method for preparation of an oral live typhoid vaccine

摘要

A cultivation method for obtaining oral live typhoid vaccine comprises the steps of cultivating seed bacteria obtained from typhoid strain Ty21a in BHI medium, suspending the cultivated bacteria in protective medium and lyophilizing the suspended bacteria in an ampoule, reviving the lyophilized bacteria and inoculating the revived bacteria in production medium, cultivating the bacteria in a fermentor, and lyophilizing the bacteria and formulating the bacteria for oral use. The preferred protective medium is composed of 8% lactose, 1% carboxymethyl cellulose (or 1% gelatin), 5% skimmed milk, 0.2% MgSO4.7H2O and 1% monosodium glutamate. The preferred growth medium is composed of 37g BHI, 5g L-lysine, 30g sorbitol, 1.5g K2HPO4, 0.5g MgSO4 and 1 litre distilled water pH 7.0. The cultivating temperature in the fermentor is controlled so that it is 30 DEG C for the first six hours, 25 DEG C for the next two hours and 20 DEG C for the final fourteen hours.