Immunization with recombinant protein Ag43::UpaH with alum and 1,25(OH)2D3 adjuvants significantly protects Balb/C mice against urinary tract infection caused by uropathogenic Escherichia coli

Uropathogenic Escherichia coli infection: innate immune disorder, bladder damage, and Tailin Fang II

Background

Uropathogenic Escherichia coli (UPEC) activates innate immune response upon invading the urinary tract, whereas UPEC can also enter bladder epithelial cells (BECs) through interactions with fusiform vesicles on cell surfaces and subsequently escape from the vesicles into the cytoplasm to establish intracellular bacterial communities, finally evading the host immune system and leading to recurrent urinary tract infection (RUTI). Tailin Fang II (TLF-II) is a Chinese herbal formulation composed of botanicals that has been clinically proven to be effective in treating urinary tract infection (UTI). However, the underlying therapeutic mechanisms remain poorly understood.

Methods

Network pharmacology analysis of TLF-II was conducted. Female Balb/C mice were transurethrally inoculated with UPEC CFT073 strain to establish the UTI mouse model. Levofloxacin was used as a positive control. Mice were randomly divided into four groups: negative control, UTI, TLF-II, and levofloxacin. Histopathological changes in bladder tissues were assessed by evaluating the bladder organ index and performing hematoxylin-eosin staining. The bacterial load in the bladder tissue and urine sample of mice was quantified. Activation of the TLR4-NF-κB pathway was investigated through immunohistochemistry and western blotting. The urinary levels of interleukin (IL)-1β and IL-6 and urine leukocyte counts were monitored. We also determined the protein expressions of markers associated with fusiform vesicles, Rab27b and Galectin-3, and levels of the phosphate transporter protein SLC20A1. Subsequently, the co-localization of Rab27b and SLC20A1 with CFT073 was examined using confocal fluorescence microscopy.

Results

Data of network pharmacology analysis suggested that TLF-II could against UTI through multiple targets and pathways associated with innate immunity and inflammation. Additionally, TLF-II significantly attenuated UPEC-induced bladder injury and reduced the bladder bacterial load. Meanwhile, TLF-II inhibited the expression of TLR4 and NF-κB on BECs and decreased the urine levels of IL-1β and IL-6 and urine leukocyte counts. TLF-II reduced SLC20A1 and Galectin-3 expressions and increased Rab27b expression. The co-localization of SLC20A1 and Rab27b with CFT073 was significantly reduced in the TLF-II group.

Conclusion

Collectively, innate immunity and bacterial escape from fusiform vesicles play important roles in UPEC-induced bladder infections. Our findings suggest that TLF-II combats UPEC-induced bladder infections by effectively mitigating bladder inflammation and preventing bacterial escape from fusiform vesicles into the cytoplasm. The findings suggest that TLF-II is a promising option for treating UTI and reducing its recurrence.

Uropathogenic Escherichia coli endeavors: an insight into the characteristic features, resistance mechanism, and treatment choice

Uropathogenic Escherichia coli (UPEC) are the strains diverted from the intestinal status and account mainly for uropathogenicity. This pathotype has gained specifications in structure and virulence to turn into a competent uropathogenic organism. Biofilm formation and antibiotic resistance play an important role in the organism's persistence in the urinary tract. Increased consumption of carbapenem prescribed for multidrug-resistant (MDR) and Extended-spectrum-beta lactamase (ESBL)-producing UPECs, has added to the expansion of resistance. The World Health Organization (WHO) and Centre for Disease Control (CDC) placed the Carbapenem-resistant Enterobacteriaceae (CRE) on their treatment priority lists. Understanding both patterns of pathogenicity, and multiple drug resistance may provide guidance for the rational use of anti-bacterial agents in the clinic. Developing an effective vaccine, adherence-inhibiting compounds, cranberry juice, and probiotics are non-antibiotical approaches proposed for the treatment of drug-resistant UTIs. We aimed to review the distinguishing characteristics, current therapeutic options and promising non-antibiotical approaches against ESBL-producing and CRE UPECs.