Relationship between biofilm formation and antibiotic resistance of Klebsiella pneumoniae and updates on antibiofilm therapeutic strategies.

Klebsiella pneumoniae is a Gram-negative bacterium within the Enterobacteriaceae family that can cause multiple systemic infections, such as respiratory, blood, liver abscesses and urinary systems. Antibiotic resistance is a global health threat and K. pneumoniae warrants special attention due to its resistance to most modern day antibiotics. Biofilm formation is a critical obstruction that enhances the antibiotic resistance of K. pneumoniae. However, knowledge on the molecular mechanisms of biofilm formation and its relation with antibiotic resistance in K. pneumoniae is limited. Understanding the molecular mechanisms of biofilm formation and its correlation with antibiotic resistance is crucial for providing insight for the design of new drugs to control and treat biofilm-related infections. In this review, we summarize recent advances in genes contributing to the biofilm formation of K. pneumoniae, new progress on the relationship between biofilm formation and antibiotic resistance, and new therapeutic strategies targeting biofilms. Finally, we discuss future research directions that target biofilm formation and antibiotic resistance of this priority pathogen.

Co-biosynthesis of germacrene A, a precursor of ß-elemene, and lycopene in engineered Escherichia coli.

ß-Elemene is the major component of a traditional Chinese medicine (Rhizoma Curcumae) for cancer treatment, and plant extraction is the major methods currently. Biosynthesis of ß-elemene is a promising and attractive route due to its advantages, including environmentally friendly processes, renewable resources, and sustainable development. In this research, biosynthesis of germacrene A, direct precursor of ß-elemene, in Escherichia coli was successfully performed and 11.99 mg/L germacrene A was obtained. Thereafter, a cobiosynthesis system for germacrene A and lycopene, another kind of isoprenoid, was constructed. Furthermore, the cultivation conditions were optimized. The germacrene A production was increased to the highest level reported to date, 364.26 mg/L, threefold increase to the strain with only germacrene A production. The cobiosynthesis system was suggested to promote the metabolic flux for germacrene A production. This research enabled germacrene A production in E. coli, and it highlights the promoting mechanism of the cobiosynthesis system for two chemicals which are both belonging to isoprenoids. KEY POINTS : • Co-production of germacrene A and lycopene in E. coli. • Promoting mechanism of cobiosynthesis of two isoprenoid compounds in E. coli. • Shake-flask production of germacrene A reached to the highest 364.26 mg/L in E. coli.