Bacterial cells adopt various strategies to adapt themselves in diverse environmental conditions. Salmonella is one such bacteria with diverse mechanisms to survive, replicate and infect in wide host range. This study aims at investigating the biofilm-forming ability of multidrug-resistant and sensitive Salmonella serovars on exposure to bile. Antibiogram of all the isolates was determined by disk diffusion method and their biofilm-forming ability in the presence or absence of bile was assessed by microtiter plate assay. Biofilm results were validated by calcofluor, Congo red plate and test tube method. Few isolates were selected for further study of their expression of biofilm related genes on exposure to bile using real time PCR. Among the 59 isolates of Salmonella isolated from seafood and poultry, 30 isolates were multi-drug resistant (MDR). Under control conditions, 57% (n = 25) of the serovars were able to form biofilm. While, 86% (n = 51) of the serovars produced biofilm in the presence of bile. The relative gene expression study of the selected serovars for 8 different genes showed a striking difference in the expression levels, supporting the hypothesis that the presence of bile triggers biofilm formation in food associated strains of non-typhoidal Salmonella by upregulation of genes involved in biofilm production.

细菌细胞采取各种策略使其适应各种环境条件。沙门氏菌就是这样一种细菌，它具有在广泛宿主范围内存活，复制和感染的多种机制。这项研究旨在调查多药耐药和敏感的沙门氏菌血清暴露于胆汁时的生物膜形成能力。通过圆盘扩散法确定所有分离物的抗菌谱，并通过微量滴定板分析评估在存在或不存在胆汁的情况下它们的生物膜形成能力。生物膜结果通过calcofluor，刚果红板和试管法进行了验证。选择很少的分离物用于进一步研究使用实时PCR暴露于胆汁中生物膜相关基因的表达。在59株沙门氏菌中从海鲜和家禽中分离出的30种分离物具有多重耐药性（MDR）。在对照条件下，57％（n = 25）的血清型能够形成生物膜。而在胆汁中，有86％（n = 51）的血清形成生物膜。对选定的血清型8种不同基因进行的相对基因表达研究表明其表达水平存在显着差异，支持以下假设：胆汁的存在会通过上调参与生物膜生产的基因来触发与食物相关的非伤寒沙门氏菌菌株中生物膜的形成。。