Overexpression of Enhances the Biofilm Formation and Virulence of .

, a strictly aerobic, non-lactose fermented Gram-negative bacteria, is one of the important pathogens of nosocomial infection. Major facilitator superfamily (MFS) transporter membrane proteins are a class of proteins that widely exists in microbial genomes and have been revealed to be related to biofilm formation in a variety of microorganisms. However, as one of the MFS transporter membrane proteins, little is known about the role of BIT33_RS14560 in . To explore the effects of BIT33_RS14560 on biofilm formation of , the biofilm formation abilities of 62 isolates were firstly investigated and compared with their transcript levels of . Then, this specific gene was over-expressed in a standard strain (ATCC 19606) and two isolates of extensively drug-resistant (XDR-Ab). Bacterial virulence was observed using a infection model. High-throughput transcriptome sequencing (RNA seq) was performed on ATCC 19606 over-expressed strain and its corresponding empty plasmid control strain. correlation analysis indicated a significant negative correlation (, ) between the △CT levels of BIT33_RS1456 and biofilm grading of isolates. The amount of biofilm was relatively high within 12-48 h. Regardless of standard or clinical strains; the biofilm biomass in the overexpression group was significantly higher than that in the control group (). Kaplan-Meier survival curve analysis showed that the mortality of was significantly higher when infected with the overexpression strain (). RNA-Seq showed that the mRNA expression levels of three genes annotated as OprD family outer membrane porin, glycosyltransferase family 39 protein, and glycosyltransferase family 2 protein, which were related to bacterial adhesion, biofilm formation, and virulence, were significantly upregulated when was over-expressed. Our findings provided new insights in identifying potential drug targets for the inhibition of biofilm formation. We also developed a practical method to construct an over-expressed vector that can stably replicate in XDR-Ab isolates.