Arishabhas Tantibhadrasapa. Alternative ways to combat multidrug-resistant Uropathogenic Escherichia coli infections: roles of lactic acid bacteria and bacteriophage. Doctoral Degree(Microbiology). Chiang Mai University. Library. : Chiang Mai University, 2025.
Alternative ways to combat multidrug-resistant Uropathogenic Escherichia coli infections: roles of lactic acid bacteria and bacteriophage
Abstract:
The rise of multidrug-resistant (MDR) uropathogenicEscherichia coli (UPEC) strains pose a significant threat to medical care. Recurrent bacterial urinary tract infections (UTIs) caused by UPEC are among the most common infectious diseases globally, highlighting the critical need for alternative therapeutic interventions.Lactic-acid-producing bacteria (LAB) from the genusLimosilactobacillus are among the most widely studied and used probiotics. However, strain-specific effects play a crucial role in determining their outcomes.Limosilactobacillus reuteri KUB-AC5, originally isolated from the chicken intestine, has shown antimicrobial effects against pathogens, includingSalmonella andE. coli. This dissertation investigated both direct and indirect effects of AC5 against UPECin vitro using cell culture model. Our data show that viable AC5 cells and their cell-free components significantly reduced UPEC (UTI89, CFT073, and clinical MDR UPEC AT31) growth in culture media. Moreover, AC5 reduced UPEC adhesion and invasion in human bladder epithelial cells. In terms of its indirect immunomodulatory effect, AC5 enhanced phagocytic killing activity of macrophage cells.Alternatively, bacteriophage therapy has long been recognized as a promising for treating bacterial infections due to the specificity of phage killing, as well as the vast diversity and abundance of phages on Earth. However, there are limitations to phage therapy, such as bacterial resistance to phages and potential effects on host immunity.Another study in this dissertation, we discovered a novelE. coli myophage capable of effectively targetingE. coli, including UPEC strain CFT073. This phage exhibited stability across a broad range of pH levels and temperatures. However, phage-resistance UPEC was observed within eight hours after the treatment. Then, we investigated a synergistic approach combining phage therapy with commonly used antibiotics (amikacin, ciprofloxacin, and piperacillin). Phage and antibiotics demonstrated a synergistic effect in inhibiting bacterial re-growth.These findings suggest that AC5 and Killian phage-antibiotic combination have the potential to serve as promising alternative interventions for combating UTI from MDR UPEC.