Enterococcus faecalis Uses a Phosphotransferase System Permease and a Host Colonization-Related ABC Transporter for Maltodextrin Uptake

• Published in: Journal of bacteriology Vol. 199; no. 9; p. E00878
• Main Authors: Sauvageot, Nicolas, Mokhtari, Abdelhamid, Joyet, Philippe, Budin-Verneuil, Aurélie, Blancato, Víctor S, Repizo, Guillermo D, Henry, Céline, Pikis, Andreas, Thompson, John, Magni, Christian, Hartke, Axel, Deutscher, Josef
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 01.05.2017
• Subjects: ABC transporter; ABC transporters; Animals; ATP-Binding Cassette Transporters - genetics; ATP-Binding Cassette Transporters - metabolism; Bacteria; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Biological Transport; Colonization; Degradation; Enterococcus faecalis; Enterococcus faecalis - enzymology; Enterococcus faecalis - genetics; Enterococcus faecalis - growth & development; Enterococcus faecalis - metabolism; Genes; Glucose; Glycogen; Inactivation; Infections; Isomers; Kidney - microbiology; Kidneys; Life Sciences; Liver; Liver - microbiology; Maltodextrin; Maltose; Maltose - pharmacology; Maltotetraose; Maltotriose; Membrane proteins; Membrane Transport Proteins - genetics; Mice; Mutation; Oligosaccharides - metabolism; Permease; Phosphoenolpyruvate Sugar Phosphotransferase System - genetics; Phosphoenolpyruvate Sugar Phosphotransferase System - metabolism; Phosphotransferase; Polysaccharides - metabolism; Residues; Rodents; Starch; Trisaccharides - pharmacology; maltodextrin; ABC transporter; phosphotransferase system; enterococci; host colonization
• ISSN: 0021-9193; 1098-5530
• DOI: 10.1128/JB.00878-16

Maltodextrin is a mixture of maltooligosaccharides, which are produced by the degradation of starch or glycogen. They are mostly composed of α-1,4- and some α-1,6-linked glucose residues. Genes presumed to code for the maltodextrin transporter were induced during enterococcal infection. We therefore carried out a detailed study of maltodextrin transport in this organism. Depending on their length (3 to 7 glucose residues), takes up maltodextrins either via MalT, a maltose-specific permease of the phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS), or the ATP binding cassette (ABC) transporter MdxEFG-MsmX. Maltotriose, the smallest maltodextrin, is primarily transported by the PTS permease. A mutant therefore exhibits significantly reduced growth on maltose and maltotriose. The residual uptake of the trisaccharide is catalyzed by the ABC transporter, because a double mutant no longer grows on maltotriose. The trisaccharide arrives as maltotriose-6″-P in the cell. MapP, which dephosphorylates maltose-6'-P, also releases P from maltotriose-6″-P. Maltotetraose and longer maltodextrins are mainly (or exclusively) taken up via the ABC transporter, because inactivation of the membrane protein MdxF prevents growth on maltotetraose and longer maltodextrins up to at least maltoheptaose. also utilizes panose and isopanose, and we show for the first time, to our knowledge, that in contrast to maltotriose, its two isomers are primarily transported via the ABC transporter. We confirm that maltodextrin utilization via MdxEFG-MsmX affects the colonization capacity of , because inactivation of significantly reduced enterococcal colonization and/or survival in kidneys and liver of mice after intraperitoneal infection. Infections by enterococci, which are major health care-associated pathogens, are difficult to treat due to their increasing resistance to clinically relevant antibiotics, and new strategies are urgently needed. A largely unexplored aspect is how these pathogens proliferate and which substrates they use in order to grow inside infected hosts. The use of maltodextrins as a source of carbon and energy was studied in and linked to its virulence. Our results demonstrate that can efficiently use glycogen degradation products. We show here that depending on the length of the maltodextrins, one of two different transporters is used: the maltose-PTS transporter MalT, or the MdxEFG-MsmX ABC transporter. MdxEFG-MsmX takes up longer maltodextrins as well as complex molecules, such as panose and isopanose.