A novel probiotic strain of Lactobacillus fermentum TIU19 isolated from Haria beer showing both in vitro antibacterial and antibiofilm properties upon two multi resistant uro-pathogen strains

Abstract

Probiotics with antimicrobial activity are gaining interest as a topic in the research field. Urinary tract infections (UTIs), acquired in the hospital or the community, are among the most prevalent infections. The emergence of multidrug resistance (MDR) uro-pathogens has made the current situation more critical in terms of global public health. To face this situation, in this study, Lactobacillus fermentum TIU19 (L. fermentum TIU19) was isolated and characterized as a new probiotic strain of the rice-based fermented beverage Haria. Subsequently, we also investigated its application as a biological agent that inhibits the growth of multidrug-resistant uro-pathogens, Escherichia coli, and Enterococcus faecalis. The results showed that, the isolated strain L. fermentum TIU19 was sensitive to all antibiotics tested except vancomycin and was devoid of virulence factors, such as haemolytic and gelatinase activities. Therefore, it may be considered safe for public health. It has many probiotic properties, such as survival in simulated gastrointestinal fluid, antioxidant activity, β-galactosidase producing ability, high cell surface hydrophobicity, adhesion ability to epithelial cells, and strong biofilm producer. The growth inhibitory and antibiofilm activities were shown against two uro-pathogens. All these results suggest that L. fermentum TIU19 can be explored as a potential probiotic with antagonistic activity against MDR uro-pathogenic E. coli and E. faecalis.

Keywords: Antibacterial-antibiofilm; Haria; Lactic-acid-bacteria; Probiotic; Uro-pathogens.

Graphical abstract

Fig. 1

(A) Cladogram representation of bacteria isolated from Haria. (B) Haemolytic activity of L. fermentum TIU19. (C) Gelatinase activity of L. fermentum TIU19.

Fig. 2

Survival of L. fermentum TIU19 in (A) the presence of acid (B) bile-containing buffer (C) simulated gastric fluid (D) simulated intestinal fluid.

Fig. 3

(A) The bar diagram represents the biofilm-forming potential of L. fermentum TIU19 at different time points. Data are represented as the mean ± SEM, where n = 3. The pictures above the bar are representing respective well stained with crystal violet. (B) Light microscopic observation of wells stained with crystal violet after 72 h of incubation in the absence and presence of L. fermentum TIU19 depicted the good biofilm-forming ability of the isolated L. fermentum.

Fig. 4

(A) DPPH radical scavenging property of L. fermentum TIU19 in a concentration-dependent manner. Data are represented as the mean ± SEM, where n = 3.

Fig. 5

(A) The bar diagram represents the anti-adhesion ability of L. fermentum TIU19 against E. coli and E. faecalis. (B and C) The bar diagram represents the log (CFU/ml) of planktonic and adherence cells of E. coli (B) and E. faecalis (C) in the presence and absence of L. fermentum TIU19. Data are represented as the mean ± SEM, where n = 3.