Comparative Observation on Eight Preservation Methods of Pathogenic Bacteria
8种不同方法保藏病原菌效果的对比观察

Eight different preservation methods for eighteen common pathogenic bacteria were compared for their preservation time and their influences upon their biological characteristics. The results indicated: freeze-drying method could do the longest preservation (at least 15 years) while beef broth agar plate method did the shortest (only 2 to 3 months). If the preservation time was put into order, it went like this: freeze-drying method > semisolid freeze method>semisolid slope covered with paraffin oli method > semisolid slope method > beef broth covered with paraffin oil method > blood agar plate method > beef broth agar plate method. However, even the same method had different preservation time for different pathogenic bacteria. The pathogenic bacteria whose preservation time was within a year had no changes in their biological characteristics while some pathogenic bacteria such as corynebacterium diphtheriae, staphylococcus aureus, salmonella paratyphi A, salmonella paratyphi B, which was preserved by means of freeze-drying method, had some changes in their biological characteristics.