Petersen L
Danish Veterinary Laboratory, Diagnostic Bacteriology Section, Copenhagen, Denmark.
Acta Vet Scand. 1997;38(1):79-85. doi: 10.1186/BF03548510.
Two selective plating media were compared to determine their performance in a three-step protocol for isolation of Salmonella from faecal, litter, and fluff samples. The enrichment protocol consisted of: 1) Preenrichment in buffered peptone water (BPW), 2) Selective enrichment in Rappaport-Vassiliadis broth, and 3) Plating onto EF-18 agar and BGA/L simultaneously. From a total of 1101 samples, Salmonella was isolated from 158, 157 of which were faecal samples. Thirty-one of these isolates were recovered on one medium only, 18 could not be found on BGA/L and 13 could not be found on EF-18 agar. The relative specificity and sensitivity of each plating agar was determined by enumeration of false-positive and false-negative reactions. EF-18 agar compared favourably with BGA/L, displaying a sensitivity of 0.92 as opposed to 0.89 for BGA/L, calculated for the "fecal samples" group only. The calculated specificities for each group of samples were likewise considerably higher for EF-18 agar (0.75-0.91) than for BGA/L (0.35-0.55). Though EF-18 agar is slightly more expensive than BGA/L, the routine use of the former may result in a considerable reduction in overall laboratory costs due to its superior selectivity. On the other hand the combination of the 2 media clearly would reduce the number of false negative results, with little extra cost.
比较了两种选择性平板培养基，以确定它们在从粪便、垫料和绒毛样品中分离沙门氏菌的三步方案中的性能。富集方案包括：1）在缓冲蛋白胨水（BPW）中进行预富集，2）在Rappaport-Vassiliadis肉汤中进行选择性富集，3）同时接种到EF-18琼脂和BGA/L上。在总共1101个样品中，分离出158株沙门氏菌，其中157株为粪便样品。这些分离株中有31株仅在一种培养基上被检出，18株在BGA/L上未检出，13株在EF-18琼脂上未检出。通过计数假阳性和假阴性反应来确定每种平板琼脂的相对特异性和敏感性。与BGA/L相比，EF-18琼脂表现良好，仅针对“粪便样品”组计算，其敏感性为0.92，而BGA/L为0.89。同样，EF-18琼脂每组样品的计算特异性（0.75 - 0.91）也明显高于BGA/L（0.35 - 0.55）。虽然EF-18琼脂比BGA/L略贵，但由于其优越的选择性，常规使用前者可能会导致实验室总成本大幅降低。另一方面，两种培养基联合使用显然会减少假阴性结果的数量，且成本增加很少。
