Restriction of the growth and biofilm formation of ESKAPE pathogens by caprine gut-derived probiotic bacteria

Abstract

The accelerated rise of antimicrobial resistance (AMR) poses a significant global health risk, necessitating the exploration of alternative strategies for combating pathogenic infections. Biofilm-related infections, which are unresponsive to standard antibiotics, often require the use of higher-order antimicrobials with toxic side effects and a potential for disrupting the microbiome. Probiotic therapy, with its diverse benefits and inherent safety, is emerging as a promising approach for preventing and treating various infections and as an alternative to antibiotic therapy. In this study, we isolated novel probiotic bacteria from the gut of domestic goats (Capra hircus) and evaluated their antimicrobial and antibiofilm activities against the ESKAPE group of pathogens. We performed comprehensive microbiological, biochemical, and molecular characterizations, including analysis of the 16S-rRNA gene V1-V3 region and the 16S-23S ISR region, on 20 caprine gut-derived lactic acid bacteria (LAB). Among these, six selected LABs demonstrated substantial biofilm formation in anaerobic conditions, and exhibited robust cell surface hydrophobicity and autoaggregation properties highlighting their superior enteric colonization capability. Notably, these LAB isolates exhibited broad-spectrum growth inhibitory and anti-biofilm properties against ESKAPE pathogens. Additionally, the LAB isolates were susceptible to antibiotics listed by the European Food Safety Authority (EFSA), within the prescribed Minimum Inhibitory Concentration limits, suggesting their safety as feed additives. The remarkable probiotic characteristics exhibited by the caprine gut-derived LAB isolates in this study strongly endorse their potential as compelling alternatives to antibiotics and as direct-fed microbial (DFM) feed supplements in the livestock industry, addressing the escalating need for antibiotic-free animal products.