3种平板计数琼脂培养基的质量比较

平板计数琼脂培养基主要用于食品中菌落总数的测定,其质量的优劣影响微生物的生长,直接影响食品中菌落总数测定结果的准确度。为了选出较好的平板计数琼脂培养基应用于微生物检验,对实验室中使用的3种平板计数琼脂培养基进行了外观、pH值和水分含量等理化性质以及菌落总数、生长率和菌落直径等生物学性能的比较。结果表明,3种平板计数琼脂培养基的质量由高到低依次是PCA-101>PCA-303>PCA-202。

3种培养基对鸡肉产品中两类耐药菌培养的影响

目的:评估不同培养基对鸡肉产品表面四环素耐药(T^(r))菌和磺胺耐药(S^(r))菌菌群的培养效果差异。方法:基于高通量测序技术,分析分别在脑心浸液肉汤(BHI)、胰蛋白胨大豆琼脂(TSA)和平板计数琼脂(PCA)3种培养基上培养获得的冷鲜鸡和鸡肉熟食表面T^(r)菌和S^(r)菌的菌群结构及丰度。结果:在冷鲜鸡表面鉴定到的101个属的耐药细菌中,仅在BHI、TSA和PCA培养基上获得培养的特有T^(r)菌属各有30,5,3个,特有S^(r)菌属各有9,8,14个;在鸡肉熟食样品表面鉴定到的50个属的耐药菌中,3种培养基上的特有T^(r)菌属分别为3,2,1个,特有S^(r)菌属分别为1,6,0个。耐药菌属丰度差异的Metastat分析结果表明,BHI和TSA对耐药菌群的结构影响具有较高的相似性,冷鲜鸡表面4种T^(r)菌(气单胞菌属Aeromonas spp.、水栖菌属Enhydrobacter spp.、乳杆菌属Lactobacillus spp.和泛菌属Pantoea spp.)和2种S^(r)菌(肠球菌属Enterococcus spp.和乳杆菌属Lactobacillus spp.)在PCA培养基上获得培养的稳定性及丰度均较高。结论:不同培养基获得耐药菌的种类及丰度存在差异,应汇总多种培养基培养所得菌群的测序信息,才能完整描述鸡肉样品表面耐药菌的组成。

Assessment of Water Microbiologic Pollution in Durres＇s Marine Harbour Basin, Albania

The aim of this study is to assess the water microbiologic pollution in Durres＇s Harbour basin and to compare it with European standards. The comparison of heterotrophs and total coliforms level in sampling are the essence of this research. The object of this study is done in four sampling areas of Durres＇s Harbour basin. In order to compare the level of water microbiologic pollution in four areas of Durres＇s Harbour basin, control area is also studied which is a beach area near the Harbour named Apollonia Beach. The sampling areas were： Ferry Terminal （FT）, Fishery Harbor （FH）, East Zone （EZ）, Fuel Quay （FQ） and Apollonia Beach （AB）, respectively. The period of sample-taking was July-October 2008. The strategy used for this purpose consisted in water insemination with coverage method by means of Petri＇s plates according to respective dilutions in culture media Plate Count Agar （PCA） for heterotrophs and MacConkey for total coliforms. The number of colonies that are formed determines the number of cells at the moment of water insemination, the number of heterotrophs in culture media PCA, respectively. The number of pink and red colonies that were formed determines the number of cells at the moment of water insemination, the number of total coliforms in culture media MacConkey, respectively. The measure ofheterotrophic bacteria and total coliforms used is Colony-Forming Units （CFU）/100 mL seawater. （AB） is within European standards. The richest area with heterotrophs is （FH）, which confirms the fact that it is the most polluted microbiologic area in the Harbour basin of Durres. The richest area with total coliforms is （FT）. The poorest area with heterotrophs and total coliforms is （FQ）.