Transient Bacterial Strain for Antibiotic-Resistant Enterococcus Elimination
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Solution Overview
Problem
Enterococcus faecalis, despite its potential as a probiotic, can invade the host and develop antibiotic resistance, leading to difficult-to-treat infections, and its bacteriocin delivery strain may acquire resistance traits and conjugate bacteriocin plasmids, posing challenges in eliminating drug-resistant enterococci without disrupting the gut microbiota.
Innovation Solution
Engineering a modified Enterococcal strain with a ΔsrtA mutation and plasmids encoding Bac21, where the first plasmid is mutated to prevent bacteriocin production and conjugation, while a second plasmid enables bacteriocin production, ensuring efficient delivery without long-term colonization or trait transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bacteriocin delivery strain of Enterococcus faecalis is used to eliminate drug-resistant enterococci, then the antibacterial activity against enterococci is improved, but the delivery strain itself may acquire antibiotic resistance traits through horizontal genetic exchange
Solution Approach 1:
The engineered E. faecalis strain is designed as a transient, non-persistent delivery vehicle that completes its bacteriocin delivery function and is then naturally eliminated from the GI tract within 7-10 days, preventing long-term colonization and reducing the window of opportunity for resistance gene acquisition and horizontal transfer to other bacteria
Solution Approach 2:
The sortase A enzyme gene (srtA) is deleted from the E. faecalis strain to extract the colonization capability, allowing the bacterium to deliver bacteriocin effectively while preventing stable residence in the GI tract and subsequent resistance development
2Productivity
If the bacteriocin delivery strain takes up residence in the intestinal tract to deliver bacteriocin, then the delivery efficiency is improved, but the strain may eventually acquire additional antibiotic resistance traits through horizontal genetic exchange
Solution Approach 1:
The strain is pre-engineered with deleted srtA gene and modified plasmids before delivery to ensure it can perform bacteriocin production and delivery functions effectively during its transient presence, without requiring long-term adaptation or colonization in the host GI tract
Solution Approach 2:
The delivery strain is designed as a transient organism that persists only long enough to deliver its bacteriocin payload and then is naturally cleared from the system, minimizing exposure time for potential genetic exchange events
3Object-affected harmful factors
If the delivery strain is engineered to prevent stable colonization, then the risk of resistance acquisition is reduced, but the ability to maintain effective bacteriocin delivery over time may be compromised
Solution Approach 1:
The non-persistent nature of the strain creates periodic pulses of bacteriocin delivery as new strains are administered, maintaining therapeutic effect over time through repeated short-term action rather than continuous long-term colonization
Solution Approach 2:
Although individual strains are transient, continuous or repeated administration maintains ongoing bacteriocin delivery activity in the GI tract, ensuring sustained therapeutic effect without requiring any single strain to persist long-term
Data Source
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AI summary
The present disclosure provides engineered modified strains of enterococcus faecalis (EF) that is able to produce bacteriocin but is inefficient at establishing long-term colonization of the GI track in an animal. Compositions comprising the modified strain and methods of use are also disclosed.