I am working on summarizing the research on the antibacterial effects of herbal extracts and am stuck on understanding the many variations in e.coli strains. Some papers use the ATCC categorization while others use CCM and PTCC. Even with finding the ATCC designation, I am not clear on why non-pathogenic strains are being studied ( ie. ATCC 25922). I recognize that even these strains can cause problems if contaminating the genital urinary tract. But would moderate antibacterial results with this strain also lead to disruption of normal gut flora as well?

Any resources or guidance on interpreting these in vitro studies on e. coli is greatly appreciated.