Effect of asiatic and ursolic acids on growth and virulence factors of uropathogenic Escherichia coli strains

Abstract

This work was aimed at determining the possible antimicrobial potential of asiatic acid (AA) and ursolic acid (UA) against clinical uropathogenic Escherichia coli strains (UPECs). Phylogenetic affiliations of UPECs and virulence-associated gene carriage have been identified. PCR analysis revealed that the studied E. coli strains belong to phylogenetic group B2. All bacterial isolates were grouped into 4 pathotypes. The following were determined: the minimum inhibitory concentrations (MICs) according to CLSI; P-fimbriae synthesis, based on erythrocyte agglutination; curli fibers, by using YESCA agar with congo red; swimming motility, in motility agar; and alpha-hemolysin, on sheep's-blood agar plates. The differences in antigrowth activities of AA and UA were recorded. Inhibition of P-fimbriae, curli fibers, and alpha-hemolysin production after exposure of UPECs to both AA and UA were observed. Reduction of bacterial motility was also noticed. Our results clearly show the influence of AA and UA on virulence factors of UPEC strains. However, differences between antivirulence activities of AA and UA were not found, although a higher level of antigrowth activity of AA in comparison with UA was shown.

Photodynamic enhancement of the activity of antibiotics used in urinary tract infections

“…To our knowledge, current work is the first report focused on the modulatory effect of the aPDT on antibacterial activity of antibiotics possessing different mechanisms of action against UPEC rods. The UPEC060 strain used in our study was genetically characterized previously and classified to phylogenetic group B2 [32]. The Ce6 used in this study is structurally closely related to porphyrins but with a higher degree of saturation of the ring system [33].…”

Anti-enterococcal activities of pentacyclic triterpenes

“…32 However, the results of Horiuchi et al as well as our previous studies have shown that the MICs of AA and UA against gram-negative bacteria were higher than the MICs for gram-positive strains. [10][11][12]31 Such discrepancy is associated with the structural differences between the cell walls of these 2 types of bacteria. Gram-negative bacteria have an outer membrane with lipopolysaccharide in its outer leaflet and phospholipids in the inner leaflet.…”

“…Our previous studies have shown that AA and UA change the virulence of uropathogenic Escherichia coli strains. [10][11][12] Impairment of the virulence factors decreases the pathogenicity of bacteria and thus reduces the development of infection.…”

Grazing incidence diffraction studies of the interactions between ursane-type antimicrobial triterpenes and bacterial anionic phospholipids

“…The representatives of three main classes of PT: lupanes, oleananes and ursanes are applied in the therapies of the diseases of different etiology; however, most efforts are exerted on the investigation of their anticancer [3,[6][7][8] and antibacterial properties [9][10][11]. Regarding the antibacterial properties, it was proved that the representatives of the ursane group: ␣-amyrin (AMalf) and its oxidized form ursolic acid (Urs) are effective antimicrobial agents [12][13][14]; however, the exact mechanism of their action has not been fully elucidated. Some authors claim that PT can be incorporated into the bacterial membrane, which can cause significant functional and structural alterations [15,16].…”