Inhibition of quorum sensing-mediated biofilm formation in Pseudomonas aeruginosa by a locally isolated Bacillus cereus.
Quorum sensing has been shown to play a crucial role in Pseudomonas aeruginosa pathogenesis where it activates expression of myriad genes that regulate the production of important virulence factors such as biofilm formation. Antagonism of quorum sensing is an excellent target for antimicrobial therapy and represents a novel approach to combat drug resistance. In this study, Chromobacterium violaceum biosensor strain was employed as a fast, sensitive, reliable, and easy to use tool for rapid screening of soil samples for Quorum Sensing Inhibitors (QSI) and the optimal conditions for maximal QSI production were scrutinized. Screening of 127 soil isolates showed that 43 isolates were able to breakdown the HHL signal. Out of the 43 isolates, 38 isolates were able to inhibit the violet color of the biosensor and to form easily detectable zones of color inhibition around their growth. A confirmatory bioassay was carried out after concentrating the putative positive cell-free lysates. Three different isolates that belonged to Bacillus cereus group were shown to have QSI activities and their QSI activities were optimized by changing their culture conditions. Further experiments revealed that the cell-free lysates of these isolates were able to inhibit biofilm formation by P. aeruginosa clinical isolates.
Department of Microbiology and Immunology, Faculty of Pharmacy, Helwan University, Cairo, Egypt.
Shaimaa
S
Wahman
Department of Microbiology and Immunology, Faculty of Pharmacy, Helwan University, Cairo, Egypt.
Mohamed
M
Emara
Department of Microbiology and Immunology, Faculty of Pharmacy, Helwan University, Cairo, Egypt.
Riham M
RM
Shawky
Department of Microbiology and Immunology, Faculty of Pharmacy, Kafr El Sheikh University, Egypt.
Ramadan A
RA
El-Domany
Department of Microbiology and Immunology, Faculty of Pharmacy, Ain Shams University, Egypt.
Mohammad Mabrouk
MM
Aboulwafa
D001409:Bacillus cereus / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development*; D015374:Biosensing Techniques; D002861:Chromobacterium / Q000187:drug effects / Q000502:physiology; D008826:Microbial Sensitivity Tests; D011550:Pseudomonas aeruginosa / Q000378:metabolism / Q000502:physiology*; D053038:Quorum Sensing / Q000502:physiology*; D012988:Soil Microbiology; D037521:Virulence Factors / Q000096:biosynthesis / Q000378:metabolism
D001426:Bacterial Proteins; D037521:Virulence Factors
Biofilm; CV026; Homoserine lactone; Pseudomonas aeruginosa; Quorum sensing