Antimicrobial Activity and Statistical Correlation Analysis of Lactobacillus spp. Isolated from Fermented Cassava and Corn against Pathogenic Bacterial Isolates

This study focused on the antimicrobial activity and statistical correlation analysis of lactobacillus spp. isolated from fermented cassava and corn against pathogenic bacterial isolates. Five (5) Lactobacillus strains, including Lactobacillus fermentum, Lactobacillus ghanensis, Lactobacillus delbrueckii, Lactobacillus plantarum, Lactobacillus reuteri, and two Bacillus strains; Bacillus cereus, and Bacillus pacificus, others included Lactococcus lactis and Lysinibacillus sphaericus, were evaluated for inhibitory activity against a range of pathogenic bacterial isolates. These pathogens included Candida sp., Staphylococcus sp., Pseudomonas sp., Klebsiella sp., Escherichia coli, Salmonella sp., and Streptococcus sp., with inhibition zones recorded to assess the effectiveness of each strain. Among the tested strains, Lactobacillus plantarum demonstrated the highest antimicrobial activity, showing inhibition zones of 18.1 mm against Pseudomonas sp., 15.3 mm against Candida sp., and 14.6 mm against Staphylococcus sp., while Bacillus cereus exhibited the lowest inhibitory effects. Statistical analysis, using t-tests and paired sample correlations, revealed significant relationships between certain pathogenic pairs, such as Candida sp. and Klebsiella sp. (r = 0.905, p = 0.001) and Staphylococcus sp. and Streptococcus sp. (r = 0.765, p = 0.007), indicating shared susceptibilities. A Euclidean distance proximity matrix highlighted clustering patterns among strains, with a close distance of 1.75mm observed between Lactobacillus fermentum and Lactobacillus plantarum, suggesting similar resistance profiles, while Lactobacillus delbrueckii and Bacillus pacificus displayed a larger distance of 4.32mm, reflecting distinct profiles. In conclusion, Lactobacillus species from fermented foods demonstrate promising antimicrobial properties, supporting their potential role in developing probiotic-based approaches for combating pathogenic bacteria.