Effects of lipid emulsions on the formation of Escherichia coli–Candida albicans mixed-species biofilms on PVC

Abstract

Patients receiving lipid emulsions are at increased risk of contracting catheter-related bloodstream infections (CRBSIs) in the clinic. More than 15% of CRBSIs are polymicrobial. The objective of this study was to explore the effects of lipid emulsions on the formation of Escherichia coli (E. coli)–Candida albicans (C. albicans) mixed-species biofilms (BFs) on polyvinyl chloride (PVC) surfaces and the underlying mechanism. Mixed-species BFs were produced by coculturing E. coli and C. albicans with PVC in various concentrations of lipid emulsions. Crystal violet staining and XTT assays were performed to test the mixed-species BF biomass and the viability of microbes in the BFs. The microstructures of the BFs were observed by an approach that combined confocal laser scanning microscopy, fluorescence in situ hybridization, and scanning electron microscopy. The study found that lipid emulsions could promote the formation of E. coli–C. albicans mixed-species BFs, especially with 10% lipid emulsions. The mechanism by which lipid emulsions promote mixed-species BF formation may involve significant upregulation of the expression of the flhDC, iha, HTA1, and HWP1 genes, which are associated with bacterial motility, adhesion, and BF formation. The results derived from this study necessitate strict aseptic precautions when handling lipid emulsions and avoiding the use of high concentrations of lipid emulsions for as long as possible.

Antimicrobial Resistance and Biofilms Underlying Catheter-Related Bloodstream Coinfection by Enterobacter cloacae Complex and Candida parapsilosis

“…For the most studied C. albicans , it is known that biofilm formation is linked to the transition from yeast to hyphal mode [ 33 ]. In dual biofilms of C. albicans and bacteria, different distributions have been described, such as preferential adherence to hyphae for streptococci [ 34 , 35 ] and S. aureus [ 36 ], adherence to both hyphae and yeast forms for E. coli [ 5 , 37 ], Clostridium perfringens , Bacteroides fragilis , Enterococcus faecalis or K. pneumoniae [ 37 ]. Here, for dual biofilms of C. parapsilosis , generating only pseudohyphae, and E. cloacae complex ( E. bugandensis ), we observed that the bacterium adheres to yeasts, but a more detailed observation of biofilms suggested that the bacterium predominates on the bottom layer of the biofilms.…”

“…[ 1 ]. Several studies reported the occurrence of polymicrobial CRBSI, as well as the increase in their incidence [ 4 , 5 , 6 ].…”

A Silkworm Infection Model for Evaluating <i>In Vivo</i> Biofilm Formation by Pathogenic Fungi

“…E. coli is a frequently isolated Gramnegative bacterium in bloodstream infections 51,52) . The interactions between E. coli and C. albicans in cross-kingdom dual-species biofilms have been studied in vitro [53][54][55][56] . An in vivo experimental system using silkworms for the cross-kingdom dual-species biofilm by E.coli and C. albicans was established using the clinical E. coli isolate RB-3, known for its high biofilm-forming capacity in vitro 50) .…”