Glycogen and Maltose Utilization by Escherichia coli O157:H7 in the Mouse Intestine

Abstract

Mutant screens and transcriptome studies led us to consider whether the metabolism of glucose polymers, i.e., maltose, maltodextrin, and glycogen, is important for Escherichia coli colonization of the intestine. By using the streptomycin-treated mouse model, we found that catabolism of the disaccharide maltose provides a competitive advantage in vivo to pathogenic E. coli O157:H7 and commensal E. coli K-12, whereas degradation of exogenous forms of the more complex glucose polymer, maltodextrin, does not. The endogenous glucose polymer, glycogen, appears to play an important role in colonization, since mutants that are unable to synthesize or degrade glycogen have significant colonization defects. In support of the hypothesis that E. coli relies on internal carbon stores to maintain colonization during periods of famine, we found that by providing a constant supply of a readily metabolized sugar, i.e., gluconate, in the animal's drinking water, the competitive disadvantage of E. coli glycogen metabolism mutants is rescued. The results suggest that glycogen storage may be widespread in enteric bacteria because it is necessary for maintaining rapid growth in the intestine, where there is intense competition for resources and occasional famine. An important implication of this study is that the sugars used by E. coli are present in limited quantities in the intestine, making endogenous carbon stores valuable. Thus, there may be merit to combating enteric infections by using probiotics or prebiotics to manipulate the intestinal microbiota in such a way as to limit the availability of sugars preferred by E. coli O157:H7 and perhaps other pathogens.

Salmonella enterica Serovar Typhimurium Colonizing the Lumen of the Chicken Intestine Grows Slowly and Upregulates a Unique Set of Virulence and Metabolism Genes

“…Again, this is in contrast to the findings of Jones et al (45), which showed that maltose was important for E. coli colonization of the mouse intestine. These authors also found, in contrast to our previous findings, that glycogen was a significant carbon source (57).…”

“…Despite the shortcomings of this approach, the patterns of expression were closer to our preconceptions than we imagined. Similarly, patterns of global gene transcription in Campylobacter jejuni in a similar model were found to resemble those in older birds with gut floras (92), and other similar models (e.g., a streptomycintreated mouse) have been used with E. coli with success (15,44,45). The requirement for a large number of chickens to generate sufficient RNA also meant that bacteria present in the ceca of different birds would also likely have been present at different stages of the growth cycle, depending on whether the ceca were full, had just emptied, or were freshly filled (P. Barrow, un- a Ten chickens were inoculated with the test strain.…”

Members of native coral microbiota inhibit glycosidases and thwart colonization of coral mucus by an opportunistic pathogen

“…A transposon mutant deficient in these activities was identified and tentatively mapped to the operon homologous to the E. coli malEFG maltose/maltodextrin transporter. This high-affinity ABC transporter system consists of a periplasmic maltosebinding protein encoded by malE and a transport complex encoded by malF, malG and malK (Jones et al, 2008b). On the basis of the transport functions of the operon, it was hypothesized that malEFG is necessary for proper colonization and utilization of coral mucus by the pathogen.…”

Specific Imaging of Bacterial Infection Using 6″-18F-Fluoromaltotriose: A Second-Generation PET Tracer Targeting the Maltodextrin Transporter in Bacteria

“…Extensively studied in E. coli, this transporter system has been shown to be present in many bacterial species, both gram-positive and gram-negative, including Enterococcus faecalis, Staphylococcus aureus, Streptococcus pneumoniae, Bacillus subtilis, Listeria monocytogenes, and Vibrio cholera (17). The maltodextrin transporter has also been implicated in the virulence mechanisms of some of these pathogens (18)(19)(20)(21). The transporter is a complex of 5 proteins with the outer membrane maltoporin (LamB) and the periplasmic maltose binding protein (MalE) serving as the key determinants of transporter specificity (17).…”