Stetsenko V V, Efimochkina N R, Pichugina T V
Federal Research Center of Nutrition and Biotechnology, Moscow, Russia.
Bull Exp Biol Med. 2019 Apr;166(6):759-765. doi: 10.1007/s10517-019-04435-x. Epub 2019 Apr 26.
Campylobacter genus bacteria causing campylobacteriasis are difficult to culture. This fact necessitates creation of special approaches to studies of the behavior of these pathogens during the manufacture and storage of foodstuffs. The regularities of Campylobacter jejuni transition into an uncultivable state are studied under conditions simulating the process of immersion cooling of fresh poultry products. The proportion of viable colony-forming (CFU) cells to the total count of planktonic and uncultivable cells in the population was calculated by the level of genomic DNA in the samples evaluated by quantitative real-time PCR with intercalating dyes. PCR was carried out with primers detecting the cytolethal toxin subunit B gene cdtB and invasion gene ciaB in C. jejuni strains. The count of detected cells was 5-10-fold higher than the count of CFU; the cultural method failed to detect the agent in 40% analyzed samples of superficially infected products, while the level of uncultivable cells detected by PCR was significantly higher. The relationship between culturing conditions and formation of C. jejuni biofilms was studied. The most intensive formation of film exomatrix was observed under unfavorable conditions for this microorganism at 25oC. In microaerophilic gaseous medium, weak formation of films and intensive growth of C. jejuni populations were observed. Culturing at higher temperatures (37-42oC) was in fact inessential for the film formation process.
引起弯曲杆菌病的弯曲杆菌属细菌难以培养。这一事实使得有必要创建特殊方法来研究这些病原体在食品制造和储存过程中的行为。在模拟新鲜家禽产品浸渍冷却过程的条件下，研究了空肠弯曲菌转变为不可培养状态的规律。通过使用嵌入染料的定量实时PCR评估样品中的基因组DNA水平，计算了群体中活的菌落形成（CFU）细胞与浮游和不可培养细胞总数的比例。使用检测空肠弯曲菌菌株中细胞致死毒素亚基B基因cdtB和侵袭基因ciaB的引物进行PCR。检测到的细胞数量比CFU数量高5至10倍；培养方法未能在40%的表面感染产品分析样品中检测到病原体，而通过PCR检测到的不可培养细胞水平明显更高。研究了培养条件与空肠弯曲菌生物膜形成之间的关系。在25℃这种对该微生物不利的条件下，观察到了最强烈的膜外基质形成。在微需氧气体介质中，观察到生物膜形成较弱且空肠弯曲菌群体生长旺盛。实际上，在较高温度（37 - 42℃）下培养对生物膜形成过程并不重要。
