Effect of the luxS gene on biofilm formation and antibiotic resistance by Salmonella serovar Dublin
| Autor: | Mengjiao Zhu, Junjie Li, Xiaoyu Zhu, Fengxia Lv, Xiangyu Ju, Zhaoxin Lu, Xiaomei Bie |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Salmonella 030106 microbiology Mutant medicine.disease_cause Microbiology 03 medical and health sciences Bacterial Proteins Gene expression medicine Gene chemistry.chemical_classification Strain (chemistry) Biofilm Quorum Sensing food and beverages Drug Resistance Microbial Gene Expression Regulation Bacterial biochemical phenomena metabolism and nutrition Carbon-Sulfur Lyases Quorum sensing Enzyme chemistry Biofilms sense organs Food Science |
| Zdroj: | Food Research International. 107:385-393 |
| ISSN: | 0963-9969 |
| DOI: | 10.1016/j.foodres.2018.02.039 |
| Popis: | Biofilms are communities of bacterial cells that serve to protect them from external adverse influences and enhance bacterial resistance to antibiotics and sanitizers. Here, we studied the regulatory effects of glucose and sodium chloride on biofilm formation in Salmonella serovar Dublin (S. Dublin). To analyze expression levels of the quorum sensing gene luxS, we created a luxS knockout mutant. Also, antimicrobial resistance, hydrophobicity and autoinducer-2 (AI-2) activity of both the wild-type (WT) and the mutant strain were investigated. Our results revealed that glucose was not essential for S. Dublin biofilm formation but had an inhibitory effect on biofilm formation when the concentration was over 0.1%. NaCl was found to be indispensable in forming biofilm, and it also exerted an inhibitory effect at high concentrations (>1.0%). Both the WT and the mutant strains displayed significant MIC growth after biofilm formation. An increase of up to 32,768 times in the resistance of S. Dublin in biofilm phonotype against antibiotic (ampicillin) compared to its planktonic phonotype was observed. However, S. Dublin luxS knockout mutant only showed slight differences compared to the WT strain in the antimicrobial tests although it displayed better biofilm-forming capacity than the WT strain. The mutant strain also exhibited higher hydrophobicity than the WT strain, which was a feature related to biofilm formation. The production of the quorum sensing autoinducer-2 (AI-2) was significantly lower in the mutant strain than in the WT strain since the LuxS enzyme, encoded by the luxS gene, plays an essential role in AI-2 synthesis. However, the limited biofilm-forming ability in the WT strain indicated AI-2 was not directly related to S. Dublin biofilm formation. Furthermore, gene expression analysis of the WT and mutant strains revealed upregulation of genes related to biofilm stress response and enhanced resistance in the luxS mutant strain, which may provide evidence for the regulatory role of the luxS gene in biofilm formation. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect