Characterization Of Quorum Sensing Mediated Biofilm Formation and its Inhibition In Cronobacter Sakazakii Strains

Abstract

The present investigation reported the role of quorum sensing in biofilm formation in Cronobacter sakazakii followed by the evaluation of different plant extracts for quorum sensing mediated inhibition of biofilm formation. newlineAltogether 219 samples obtained from different commodities were screened for isolation and detection of C. sakazakii. In total 45 isolates identified as Cronobacter spp. were obtained on chromogenic Enterobacter sakazakii agar ESA. Further the isolates were identified using an array of biochemical tests and molecular typing methods targeting 16S ribosomal RNA rRNA gene ITS Internal Transcribed Spacer sequences and polymerase betasubunit encoding gene rpoB. The final identity was confirmed using Multilocus sequence typing MLST targeting elongation factor fusA which resulted in confirmation of 5 isolates as Cronobacter sakazakii. These five isolates were profiled for putative virulence factors associated with pathogenesis of C. sakazakii. All the isolates exhibited and#946;hemolysis chitinase activity and were able to utilize inositol. Among the nine virulence associated genes hly gene coding for hemolysin was detected in all the isolates followed by ompA outer membrane protein; however plasmidborne virulent traits such as cpa Cronobacter plasminogen activator and eitA Ferric ion transporter protein gene were observed in few isolates. newlineThe extent of biofilm formation by confirmed C.sakazakii isolates was quantified in terms of specific biofilm formation SBF index. For determination of SBF standard microtitre plate assay was used followed by crystal violet staining. A strong SBF index was observed for all the strains with the presence of genes associated with cellulose biosynthesis bcsA bcsC and bcsG. The Extracellular Polymeric Substances EPS was extracted from the biofilm cells of C. sakazakii and the EPS was characterized for total carbohydrate and protein content. The FTIR spectroscopy of the EPS revealed the presence of COOH groups 1600 cm1 to 1725 cm1 and OH 2800 cm1 to 3600 cm1 groups indicatin