Title : Enhancing probiotic intervention for control of biofilm former escherichia coli isolates of animal-origin foods
Abstract:
Biofilm formation is a survival mechanism and adaptation strategy of microbes that allows them to live on food and food-contact surfaces for extended periods of time. Apart from causing adverse health effects, biofilms cause an estimated $324 billion impact on the global agrifood sector annually. Thus, a better understanding of the characteristic biofilm formation of microbes in the food and food-processing chain is essential for its prevention. The present study was conducted to understand the biofilm-forming ability of Escherichia coli, a major foodborne pathogen, isolated from various foods of animal origin (milk, chicken meat and chicken egg) and correlated with the multidrug resistant (MDR) pattern. Moreover, as a biofilm control strategy, probiotics have been tested to minimize biofilm formation by E. coli. The use of probiotics can be an alternative approach to reduce the formation of pathogenic biofilms in the food industry. This study evaluated two lactic acid bacterial (LAB) strains, Lactobacillus rhamnosus (LR) and Lactobacillus casei (LC), against E. coli biofilms. Both LAB strains were tested alone and in combination for their antibacterial activity using the agar spot method, anti-biofilm activity, auto-aggregation, and co-aggregation abilities against E. coli. First, the antimicrobial resistance patterns and biofilm biomass quantification of 115 E. coli isolates from milk (36), chicken meat (33), and eggs (46) were observed using the Kirby Bauer disk diffusion method and crystal violet (CV) assay, respectively. The results revealed that approximately 69.56% of the E. coli isolates were resistant to ≥3 antibiotic classes. In the biofilm assay, 24.34% were strong biofilm formers, 31.30% were moderate biofilm formers, and 45.22% were weak biofilm formers. Biofilm-forming genes, such as fimC, were positive in 50.43% of isolates, whereas crl was positive in 80.0% of isolates. Moreover, MDR isolates exhibited strong biofilm ability with a higher frequency of fimC (55.55%) and crl (85.81%) than non-MDR isolates. On determining LAB strains potential, the L. rhamnosus showed 29.10 mm antibacterial inhibition zone with 102.77% average reduction in biofilm, 59.46% auto-aggregation and 40.61% co-aggregation with E. coli isolates whereas the L. casei showed 21.80 mm antibacterial inhibition zone with 56.78% average reduction in biofilm growth, 45.23% auto-aggregation and 36.81% mean co-aggregation with E. coli isolates. On combination therapy (LR+LC), 87.49% average reduction in biofilm growth and 40.23% mean co-aggregation were observed. These findings suggest that both strains are effective in removing biofilm growth in all food-origin isolates, with L. rhamnosus proving to be more effective than L. casei. Scanning electron microscopy (SEM) images confirmed the biofilm reduction of E. coli isolates by LAB strains. This study demonstrated the effectiveness of probiotic-based strategies in reducing biofilm formation by both multi-drug resistant (MDR) and non-MDR E. coli strains. These findings indicate that implementing these strategies can contribute to improved public health and environmentally sustainable practices. These results underscore the importance of ongoing monitoring and intervention in animal food production to mitigate the risks associated with antibiotic resistance and biofilm formation.
Audience Take Away:
- Biofilm formation is a survival mechanism and an adaptation strategy employed by microbes under adverse environmental conditions. This study highlights how biofilm formation by E. coli in various animal-origin foods contributes to the long-term contamination of food and food-contact surfaces.
- Probiotics offer a promising alternative approach to control pathogenic biofilms in the food industry. This study evaluated the effectiveness of two lactic acid bacteria (Lactobacillus rhamnosus and Lactobacillus casei) in reducing biofilm formation by E. coli. The results showed that these probiotics could significantly inhibit biofilm growth and demonstrate antibacterial properties.
- The prevalence of multidrug-resistant (MDR) E. coli strains in food samples of animal origin is a cause of concern. This study observed a high percentage of MDR E. coli isolates, along with a correlation between MDR and strong biofilm-forming ability. The use of probiotics is effective in reducing biofilm formation, even in MDR strains, highlighting their potential to combat antibiotic resistance in the food industry.
- The present work will directly and indirectly provide insights to the food industry and consumers regarding the challenges and pave the way for further research in this important area.
