细菌悬液两种计数方法的比较

Comparison of two plate count methods of bacterial density determination

目的比较平板点样法与传统平板涂布计数法,建立更为简便的细菌悬液中活菌浓度的检测方法。方法将3株A群溶血性链球菌制备成多份菌悬液,稀释成不同梯度,用调理吞噬实验中的平板点样技术和传统平板涂布法同时检测,比较两种方法计数结果,分析相关性和显著差异。结果不同菌株和稀释方法中平板点样法的结果均随菌液稀释梯度呈现出较好的梯度;两种方法计数结果呈高度相关(r=0.84);二者的t检验结果比较差异无统计学意义(P>0.05)。结论相对平板涂布法,平板点样法计数更客观准确,检测范围更宽,操作更便捷,适用于菌液浓度的确定。

Objective To establish a more convenient detection method for determining concentrations of living bacteria in suspensions by comparing spot plate method with common spread plate method. Methods 3 groups of A Streptococcus strains were cultured and separately suspended in normal saline and diluted. The concentrations of the suspensions were detected by both spot plate method and spread plate method. The relationship and significant difference between the results from the two methods were analyzed. Results The counting results of different strains or diluting Way suspensions from spot plates appeared a great dilution gradient dependence. The results of the two methods showed a good correlation, r = 0.84, and there was no significant difference in t-test （P 〉 0.05）. Conclusion Compared with spread plate method, spot plate method is a more objective and convenient method for bacteria counting, which also has a wide counting range.