Quorum quenchers affect the virulence regulation of non-mucoid, mucoid and heavily mucoid biofilms co-cultured on cell lines

Abstract

Biofilm formation conferring pathogenicity is a survival strategy for Pseudomonas aeruginosa. P. aeruginosa’s virulence may differ due to differences in host-microbe interactions and the growth environment. The epithelial cell line within the respiratory system and the keratinocytes on the skin form the first physical barrier of defence. P. aeruginosa spp. biofilm formation and virulence factor secretion with and without quorum quenching (QQ) treatment was studied in co-culture using A549 and HaCaT cell lines; pyocyanin and rhamnolipid productions and elastolytic activity as virulence factors were quantified by independent assays. Biofilm formation was evaluated under dynamic conditions by quantifying total carbohydrates, alginate, proteins and eDNA. A sandwich ELISA was performed to study IL-8 secretion by the epithelial cells. The difference in gene expression of the quorum sensing (QS) and virulence factors between strains during individual and combination treatments was analysed by qPCR. Combination treatment by farnesol and tyrosol was more effective against P. aeruginosa biofilms when grown in co-cultures. The strain RBHi was found to be 3 to 4 times more virulent compared to PAO1 and NCTC 10,662, respectively, and combination treatment was more effective against RBHi strain when grown in co-culture with A549 cell line. The addition of quorum quenchers (QQs) individually and in combination reduced IL-8 secretion by A549 cells. Relative mRNA expression showed upregulation of the QS genes and virulence factors. Co-culture of P. aeruginosa and HaCaT cell line showed a general decrease in gene expression, especially in the case of P. aeruginosa RBHi when treated with farnesol and tyrosol combination.Key points• Differentiating the interactions of biofilm formed by different phenotypes of P. aeruginosa, NCTC 10,662 (non-mucoid), PAO1 (semi mucoid) and RBHi (heavily mucoid).• Biofilm formed by these P. aeruginosa strains on two commonly afflicted tissues represented by A549 (lung) and HaCaT (skin) cell lines.• Anti-biofilm/anti-virulence roles of quorum quenchers, tyrosol and farnesol in co-cultures.

Comparative Experimental Investigation of Biodegradable Antimicrobial Polymer-Based Composite Produced by 3D Printing Technology Enriched with Metallic Particles

“…Furthermore, different types of general bacteria are typically derived from the American Type Culture Collection (ATCC) and Nonprofit Culture Collection (NCTC) repositories to check the antimicrobial activities of different materials against these bacteria. Some general bacteria that are commonly tested against other antimicrobial materials and surfaces derived from the organizations mentioned above are Escherichia coli (ATCC 10536) [ 103 ], Pseudomonas aeruginosa (NCTC 10662) [ 104 ], Staphylococcus aureus (NCTC 6571), Salmonella Poona (NCTC 3940) [ 105 , 106 ], and Enterococcus faecalis [ 107 ].…”