SCV E. coli Culture Medium for Urinary Catheter Biofilm
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Solution Overview
Problem
Antimicrobial therapy for asymptomatic urinary tract infections (UTIs) in patients with indwelling urinary catheters is ineffective in preventing recurrence and often leads to antibiotic-resistant organisms, and standard media promotes reversion of small colony variants (SCVs) of E. coli to large colony variants, making it difficult to maintain SCVs in culture.
Innovation Solution
The development of methods for culturing and propagating small colony variants (SCVs) of non-pathogenic E. coli strains, such as E. coli 83972 and HU2117, using a supplemented minimal medium without adenine, cytosine, guanine, uracil, or yeast extract, and utilizing glycerol as a carbon source to maintain the SCV form, which are then incorporated into lubricant gels for biofilm formation on medical devices and in the urinary tract.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard media is used for culturing E. coli, then general bacterial growth is supported, but small colony variants (SCVs) revert to large colony variants (LCVs)
Solution Approach 1:
The patent modifies the chemical composition parameters of the culture medium by removing adenine, cytosine, guanine, uracil, and yeast extract, and by using glycerol as the sole carbon source. These parameter changes create selective pressure that maintains the SCV form while still supporting bacterial growth through alternative metabolic pathways.
Solution Approach 2:
The patent creates a specialized local environment (culture medium) with specific compositional qualities that differ from standard media. This localized modification of the culture environment provides the selective conditions needed to maintain SCVs without affecting the overall growth capability of the bacteria.
2Reliability
If antimicrobial therapy is applied to asymptomatic UTIs in catheterized patients, then transient eradication of bacteria is achieved, but antibiotic-resistant organisms emerge
Solution Approach 1:
The patent converts the harmful effect of antibiotic overuse (selecting for resistant organisms) into a beneficial outcome by using probiotic SCV E. coli to colonize the bladder. This competitive colonization prevents pathogenic bacteria from establishing infections, thereby eliminating the need for antimicrobial therapy and preventing the development of antibiotic resistance.
Solution Approach 2:
The patent introduces non-pathogenic E. coli strains as intermediary organisms that occupy ecological niches in the urinary tract. These intermediary probiotic bacteria compete with pathogenic organisms for attachment sites and resources, preventing infections without requiring direct antimicrobial intervention that would select for resistance.
3Reliability
If E. coli strains are used for bladder colonization to prevent catheter colonization, then protection against uropathogens is achieved, but maintenance of SCV form in culture becomes difficult
Solution Approach 1:
The patent establishes specific culture medium parameters (absence of adenine, cytosine, guanine, uracil, and yeast extract; presence of glycerol as sole carbon source) that enable reliable SCV propagation. These parameter changes make SCV maintenance as easy as standard bacterial culturing while preserving the protective SCV phenotype.
Data Source
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AI summary
The invention relates to methods of differentiation, isolation, propagation, and storage of small colony variants (SCVs) of E. coli, preferably E. coli 83972 or E. coli HU2117, or modified or variant forms thereof, and methods for using the prepared SCV bacteria to establish probiotic biofilms in treated subjects and/or on treated medical devices.