Evaluation of antagonistic activity of an Egyptian probiotic Lactobacillus plantarum against bacteria isolated from ready-to-eat meat products

Abstract

Background The increase in the incidence of antibiotic-resistant pathogens calls for strenuous efforts to substitute the administration of antibiotics with the use of probiotics. Aim The aim of the study was to evaluate the bacterial contamination of ready-to-eat meat products in Tanta city, determine the antibiotic susceptibility of the isolates, determine in vitro antagonistic effect of a probiotic Lactobacillus plantarum (L. plantarum) against isolates, and compare this effect with the inhibitory effect of the commonly used antibiotics. Materials and Methods The samples were collected in stomacher packs, homogenized, and serially diluted. Identification of pathogenic bacteria was done via standard microbiological methods. Antibiotic-sensitivity tests were done by disk-diffusion method. The results were compared with the inhibitory effect of L. plantarum done by well-diffusion and overlay methods. Results The total rate of bacterial contamination of the collected samples was 72/90 (80%), while the contamination rates from good sanitation-state (GS) outlets and poor sanitation-state (PS) outlets were 27/37 (72.9%) and 45/53 (84.9%), respectively. The most isolated bacteria were Escherichia coli (E. coli) (29%) followed by Staphylococcus aureus (21%). L. plantarum showed inhibitory effect against both Gram-positive and Gram-negative isolates. Its activity was maximum against E. coli and least for Klebsiella spp. in both well-diffusion and overlay methods. Conclusion The presence of pathogenic bacteria in ready-to-eat products is a great public health issue; also, this research supports the promising use of the tested L. plantarum and its products as antimicrobial agents against foodborne pathogen.