A heterologous prime-boost route of vaccination based on the truncated MrpH adhesin and adjuvant properties of the flagellin from Proteus mirabilis against urinary tract infections

Unveiling the hidden arsenal: new insights into Proteus mirabilis virulence in UTIs

Proteus mirabilis is a Gram-negative bacterium commonly found in urinary tract infections (UTIs) and catheter-associated urinary tract infections (CAUTIs). The pathogenic mechanisms of Proteus mirabilis are complex and diverse, involving various virulence factors, including fimbriae, flagella, urease, polyphosphate kinase, lipopolysaccharides, cyclic AMP receptor protein, Sigma factor RpoE, and RNA chaperone protein Hfq. These factors play crucial roles in bacterial colonization, invasion, evasion of host immune responses, biofilm formation, and urinary stone formation. This paper is the first to comprehensively describe the hydrogenase system, autotransporter proteins, molybdate-binding protein ModA, and two-component systems as virulence factors in Proteus mirabilis, providing new insights into its pathogenic mechanisms in urinary tract infections. This review explores the mechanisms of biofilm formation by Proteus mirabilis and the various virulence factors involved in UTIs, revealing many newly discovered virulence factors from recent studies. These findings may offer new targets for clinical treatment of UTIs and vaccine development, highlighting the importance of understanding these virulence factors.

Antibacterial and antibiofilm activity of halogenated phenylboronic acids against Vibrio parahaemolyticus and Vibrio harveyi

Vibrios are associated with live seafood because they are part of the indigenous marine microflora. In Asia, foodborne infections caused by Vibrio spp. are common. In recent years, V. parahaemolyticus has become the leading cause of all reported food poisoning outbreaks. Therefore, the halogenated acid and its 33 derivatives were investigated for their antibacterial efficacy against V. parahaemolyticus. The compounds 3,5-diiodo-2-methoxyphenylboronic acid (DIMPBA) and 2-fluoro-5-iodophenylboronic acid (FIPBA) exhibited antibacterial and antibiofilm activity. DIMPBA and FIPBA had minimum inhibitory concentrations of 100 μg/mL for the planktonic cell growth and prevented biofilm formation in a dose-dependent manner. Both iodo-boric acids could diminish the several virulence factors influencing the motility, agglutination of fimbria, hydrophobicity, and indole synthesis. Consequently, these two active halogenated acids hampered the proliferation of the planktonic and biofilm cells. Moreover, these compounds have the potential to effectively inhibit the presence of biofilm formation on the surface of both squid and shrimp models.

Recombinant FimH, a fimbrial tip adhesin of Vibrio parahaemolyticus, elicits mixed T helper cell response and confers protection against Vibrio parahaemolyticus challenge in murine model

Vibrio parahaemolyticus causes vibriosis in wide range of marine organisms, and is responsible for food borne illnesses in humans through consumption of contaminated uncooked/partially cooked seafood. Continued and widespread antibiotics usage to increase the productivity has led to antibiotics resistance development. This has necessitated the need to develop alternative methods to control its infection. Use of safe and effective vaccines against the virulence factors not only protects from infection, it also minimizes antibiotic usage. The colonization of V. parahaemolyticus in the host and disease development requires several adhesins present on the cell surface, and thereby make them attractive vaccine candidates. V. parahaemolyticus produces extracellular type 1 fimbriae that have been shown to play a role in adhesion, biofilm formation and virulence. FimH is one of the minor components of the type 1 fimbriae occurring on its very tip. Being present on the cell surface, it is highly immunogenic, and can be targeted as a potential vaccine candidate. The present study describes the immunogenic and vaccine potential of recombinant V. parahaemolyticus FimH (rVpFimH) expressed in E. coli. Immunization of BALB/c mice with the rVpFimH elicited a strong mixed immune response, T-cell memory (evidenced by antibody isotyping, cytokine profiling and T-cell proliferation assay), and agglutination positive antibodies. FACS analysis and immunogold labeling showed that the polyclonal anti-rVpFimH antibodies were able to recognize the FimH on V. parahaemolyticus cells. In vivo challenge of the rVpFimH-immunized mice with 2×LD₅₀ dose of live bacteria showed one hundred percent survival. Thus, our findings clearly demonstrate the potential of FimH as an effective vaccine candidate against V. parahaemolyticus.