Outer membrane defect and stronger biofilm formation caused by inactivation of a gene encoding for heptosyltransferase I in Cronobacter sakazakii ATCC BAA-894

Abstract

Aims: To investigate the role of lipopolysaccharide (LPS) structure in the stability of outer membrane and the ability of biofilm formation in Cronobacter sakazakii.

Methods and results: A C. sakazakii mutant strain LWW02 was constructed by inactivating the gene ESA_04107 encoding for heptosyltransferase I. LPS were purified from LWW02, and changes in their structure were confirmed by thin-layer chromatography and electrospray ionization mass spectrometry. Comparing with the wild-type strain BAA-894, slower growth, higher membrane permeability, higher surface hydrophobicity, stronger ability of autoaggregation and biofilm formation were observed for the mutant strain LWW02.

Conclusions: The gene ESA_04107 encodes heptosyltransferase I in C. sakazakii ATCC BAA-894. The cleavage of LPS in C. sakazakii could cause its outer membrane defects and increase its ability to form biofilms.

Significance and impact of the study: The study is important for understanding the pathogenic mechanism and efficient control of C. sakazakii.