Beckers H J, vd Heide J, Fenigsen-Narucka U, Peters R
J Appl Bacteriol. 1987 Feb;62(2):97-104. doi: 10.1111/j.1365-2672.1987.tb02386.x.
Studies have been carried out in which growth patterns of a Salmonella sp. and competing micro-organisms, especially other Enterobacteriaceae, were followed during pre-enrichment in buffered peptone water (BPw) and subsequent selective enrichment in tetrathionate broth (TBB). Pre-enrichment cultures were inoculated with minced meat and three reference samples containing nalidixic acid-resistant salmonellas. Irrespective of their initial numbers in BPw, Enterobacteriaceae increased to 10(8)/ml or more. During incubation in TBB at 43 degrees C, numbers of lactose-positive Enterobacteriaceae decreased in most enrichments which resulted in a positive salmonella isolation, but remained constant in the majority of those that did not. Levels of lactose-negative Enterobacteriaceae did not decrease in most salmonella-positive tests, but did so in half of the salmonella-negative ones. In the salmonella-positive tests the numbers of salmonellas had increased to 10(3)-10(7)/ml in BPw and after transfer to TBB slowly reached 10(4)/ml or more. In all cases the numbers of salmonellas exceeded those of the competing flora on brilliant green agar (BGA). In the salmonella-negative tests the numbers of salmonellas had increased less in BPw and decreased in most of the TBB enrichments. In none of these negative tests did the numbers of salmonellas exceed those of the competing flora on BGA. Escherichia coli dominated in most of the salmonella-negative tests. The results suggest more influence of lactose-positive than lactose-negative Enterobacteriaceae on the detection of salmonellas. The effect of competing microorganisms seems to depend not only upon their initial numbers, but also upon the types that can interact with salmonellas during selective enrichment.
已开展了多项研究，观察了沙门氏菌属菌株与竞争性微生物，尤其是其他肠杆菌科细菌，在缓冲蛋白胨水（BPw）中预富集以及随后在四硫磺酸钠肉汤（TBB）中选择性富集期间的生长模式。预富集培养物接种了碎肉和三个含有耐萘啶酸沙门氏菌的参考样品。无论它们在BPw中的初始数量如何，肠杆菌科细菌数量均增加至10⁸/ml或更多。在43℃的TBB中培养期间，大多数导致沙门氏菌分离呈阳性的富集培养物中乳糖阳性肠杆菌科细菌数量减少，但在大多数未呈阳性的培养物中保持不变。在大多数沙门氏菌阳性检测中，乳糖阴性肠杆菌科细菌数量未减少，但在一半的沙门氏菌阴性检测中减少。在沙门氏菌阳性检测中，沙门氏菌数量在BPw中已增加至10³ - 10⁷/ml，转移至TBB后缓慢达到10⁴/ml或更多。在所有情况下，沙门氏菌数量在亮绿琼脂（BGA）上均超过竞争性菌群。在沙门氏菌阴性检测中，沙门氏菌数量在BPw中增加较少，且在大多数TBB富集培养物中减少。在这些阴性检测中，沙门氏菌数量在BGA上均未超过竞争性菌群。在大多数沙门氏菌阴性检测中，大肠杆菌占主导地位。结果表明，乳糖阳性肠杆菌科细菌对沙门氏菌检测的影响大于乳糖阴性肠杆菌科细菌。竞争性微生物的影响似乎不仅取决于其初始数量，还取决于在选择性富集期间可与沙门氏菌相互作用的类型。
