稀菌液细菌数服从泊松分布及其在菌落计数方面的应用  

Bacterial count in the diluted bacterial suspension obeying poisson distribution and its application in colony counting

作　　者：邓通洋 程琮[2] 冯维良 林哈妮 

机构地区：[1]瑞安市妇幼保健院检验科,浙江温州325200 [2]泰山医学院卫生统计学教研室,山东泰安271016

出　　处：《中国卫生检验杂志》2014年第9期1255-1256,1261,共3页Chinese Journal of Health Laboratory Technology

基　　金：温州市卫生局经费自筹科技项目(2012A009)

摘　　要：目的用实验的方法阐述稀菌液中细菌数量服从泊松分布的定义及其原理,并介绍它在微生物检验中菌落计数方面的应用。方法将ATCC25922和ATCC29213 2种菌株接种到血平板经18 h^24 h培养后,用无菌生理盐水配成0.5麦氏单位约为108cfu/ml的菌液,然后经过系列梯度稀释,得到目标浓度范围约为1 cfu/ml^5 cfu/ml的系列菌悬液各200 ml,然后从中取出1 ml倾注培养,每种浓度进行100次并菌落计数,计数结果采用单样本Kolmogorov-Smirnov法检验1 ml的菌液中的细菌是否服从泊松分布。结果浓度范围为0.56 cfu/ml^6.38 cfu/ml的10个菌液每毫升的细菌数量分布均服从泊松分布,P均>0.05。结论将稀菌液服从泊松分布的原理应用到菌落计数漏检率和检出限估算方面具有重要意义。Objective To elucidate the definition and principle of bacterial count in the diluted bacterial suspension obeying a Poisson distribution based on experiment and introduce its application in colony counting in microbiological examinations. Methods ATCC25922 and ATCC29213 were inoculated and cultured on a blood plate for 18 h ～ 24 h,then the bacterial culture were prepared into 0. 5 McFarland（MF） standard（ca. 108cfu / ml） bacterial suspension with sterile saline solution. Following a series of gradient dilutions,a set of bacterial suspensions with concentration from 1 cfu / ml to 5 cfu / ml were obtained with each of 200 ml. Then the colonies were counted in per milliliter of bacterial suspension at each concentration by pour plate method, and such operation was repeated 100 times. One- sample Kolmogorov- Smirnov test was used to test the consistency of the above results and Poisson distribution. Results In each milliliter of the10 bacterial suspensions（ concentrations from 0. 56 cfu / ml to 6. 38 cfu / ml）,bacterial count per milliliter obeyed a Poisson distribution（P〉0. 05）. Conclusion It will be of great importance in applying the principle of a diluted bacterial suspension obeying a Poisson distribution to the colony counting loss and the estimation of the detection limit.

关 键 词：泊松分布 稀菌液 菌落计数 

分 类 号：R446.5[医药卫生—诊断学]