Reducing Inoculum Effect by Modulating Growth Productivity Through the Superpathway of Purine, Pyrimidine and Histidine Synthesis in Escherichia coli
Abstract
It is estimated that by 2050, 10 million people will die annually due to infections caused by antibiotic resistant bacteria. An understanding of the mechanisms that bacteria use to resist antibiotics is essential for extending the usefulness of our existing antibiotics. One mechanism that bacteria use to resist antibiotics is the inoculum effect (IE). During IE, high-density bacterial populations require higher concentrations of antibiotics to be killed compared to low-density bacterial populations. Recently, it has been discovered that growth productivity, defined as the relationship between ATP and growth rate, can explain IE for multiple antibiotics. If growth productivity is sufficiently high, IE is abolished. However, the underlying mechanisms and pathways that are critical in determining growth productivity are yet to be fully understood. Accordingly, we sought to identify pathway(s) critical in determining growth productivity and thus IE. We first used flux balance analysis coupled with whole-genome modeling and OPTKNOCK to computationally quantify changes in growth productivity as a result of single gene mutations. We found that many genes linked to increased growth productivity are concentrated in the super pathway of pyrimidine, purine, and histidine synthesis. To potentiate activity through this pathway, and rationally manipulate growth productivity, we measured IE of carbenicillin and streptomycin in the presence of exogenously added nucleotides. We found that supplementation of cultures with select nucleotides could increase growth productivity and reduce IE. Overall, our results suggest that flux through the super pathway of pyrimidine, purine, and histidine synthesis is critical in determining IE.
Faculty Sponsors
Dr. Robert P. Smith
Project Type
Event
Location
Alvin Sherman Library
Start Date
4-5-2023 12:00 PM
End Date
4-6-2023 4:00 PM
Reducing Inoculum Effect by Modulating Growth Productivity Through the Superpathway of Purine, Pyrimidine and Histidine Synthesis in Escherichia coli
Alvin Sherman Library
It is estimated that by 2050, 10 million people will die annually due to infections caused by antibiotic resistant bacteria. An understanding of the mechanisms that bacteria use to resist antibiotics is essential for extending the usefulness of our existing antibiotics. One mechanism that bacteria use to resist antibiotics is the inoculum effect (IE). During IE, high-density bacterial populations require higher concentrations of antibiotics to be killed compared to low-density bacterial populations. Recently, it has been discovered that growth productivity, defined as the relationship between ATP and growth rate, can explain IE for multiple antibiotics. If growth productivity is sufficiently high, IE is abolished. However, the underlying mechanisms and pathways that are critical in determining growth productivity are yet to be fully understood. Accordingly, we sought to identify pathway(s) critical in determining growth productivity and thus IE. We first used flux balance analysis coupled with whole-genome modeling and OPTKNOCK to computationally quantify changes in growth productivity as a result of single gene mutations. We found that many genes linked to increased growth productivity are concentrated in the super pathway of pyrimidine, purine, and histidine synthesis. To potentiate activity through this pathway, and rationally manipulate growth productivity, we measured IE of carbenicillin and streptomycin in the presence of exogenously added nucleotides. We found that supplementation of cultures with select nucleotides could increase growth productivity and reduce IE. Overall, our results suggest that flux through the super pathway of pyrimidine, purine, and histidine synthesis is critical in determining IE.
