Imziln B, Lafdal O M, Barakate M, Hassani L, Ouhdouch Y, Boussaid A, Jana M
Department of Biology, Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech, Morocco.
J Appl Microbiol. 1997 May;82(5):557-66.
Several selective media were evaluated for their suitability for the isolation and quantification of mesophilic Aeromonas species from naturally polluted samples. Satisfactory recoveries were obtained with most of them but only when densities of background microflora were low. When analysed samples were from highly polluted waters, results were inconsistent because they did not give quantitative recovery of mesophilic aeromonads or they did not permit ready differentiation of Aeromonas species from the competitive bacteria. A new medium was developed on the basis of the combination of some positive aspects of several published media, pril-ampicillin-dextrin-ethanol (PADE) agar. The medium employs dextrin (Merck 3006) as a fermentable carbohydrate and pril, ampicillin and ethanol as inhibitory substances. Recovery on PADE agar from suspensions of 15 tested strains of Aeromonas prepared from pure cultures was excellent. The confirmation rate of typical colonies designated Aeromonas spp. isolated from polluted samples exceeded 90%. Recoveries of stressed aeromonad strains on both PADE agar and a non-selective medium (TSA) did not show any significant difference (P > 0.05). PADE agar was more reliable for quantitative recovery of mesophilic aeromonads than the other selective media because of its characteristics: (i) inhibition of the swarming of Proteus, (ii) good reduction of the background, (iii) inhibition of the over growth of Klebsiella spp., (iv) absence of NaCl makes it unfavourable for the growth of halophilic vibrios, (v) combination of two pH indicators permitted a very easy differentiation between Aeromonas colonies and the competitive microflora. The medium can also be used for isolation of aeromonads from various sources by membrane filtration.
评估了几种选择性培养基用于从天然污染样品中分离和定量嗜温气单胞菌属的适用性。大多数培养基都能获得令人满意的回收率，但前提是背景微生物群落密度较低。当分析的样品来自高污染水体时，结果不一致，因为它们不能对嗜温气单胞菌进行定量回收，或者不能轻易地将气单胞菌属与竞争性细菌区分开来。基于几种已发表培养基的一些积极方面，开发了一种新的培养基，即普里-氨苄青霉素-糊精-乙醇（PADE）琼脂。该培养基使用糊精（默克3006）作为可发酵碳水化合物，普里、氨苄青霉素和乙醇作为抑制物质。从纯培养物制备的15株受试气单胞菌菌株的悬浮液在PADE琼脂上的回收率极佳。从污染样品中分离出的典型菌落被鉴定为气单胞菌属的确认率超过90%。在PADE琼脂和非选择性培养基（TSA）上，应激气单胞菌菌株的回收率没有显著差异（P>0.05）。由于其特性，PADE琼脂在嗜温气单胞菌的定量回收方面比其他选择性培养基更可靠：（i）抑制变形杆菌的群游；（ii）良好地减少背景；（iii）抑制克雷伯菌属的过度生长；（iv）不含氯化钠使其不利于嗜盐弧菌的生长；（v）两种pH指示剂的组合使气单胞菌菌落与竞争性微生物群落之间的区分非常容易。该培养基还可用于通过膜过滤从各种来源分离气单胞菌。
