Antibacterial potential of lactic acid bacteria isolated from raw cow milk in Sylhet district, Bangladesh: A molecular approach.

BACKGROUND: The most prevalent probiotic bacterium employed in the food industry is Lactobacillus because it can produce metabolites with antibacterial capabilities and exhibits hostility towards infections and microorganisms that cause spoilage. AIM: This study set out to identify naturally occurring Lactobacillus and plantaricin (pln EF) coding genes in raw cow milk and to assess the antibacterial potency of isolated Lactobacillus isolates. METHODS: Following enrichment in De Man, Rogosa and Sharpe (MRS) broth, single colonies were isolated, and pure colonies were obtained by streaking on MRS agar. The 16S rRNA gene was amplified using polymerase chain reaction (PCR) to confirm the cultural positivity of all isolates. Additionally, the presence of plantaricin was verified by targeting the pln EF gene through PCR. OUTCOME: Out of the 166 raw milk specimens acquired from cows, 153 (91.17%; CI: 86.98-95.76) were identified as positive for Lactobacillus through both culture and biochemical screening. Subsequently, 121 (72.89%; CI: 65.46-79.49) of the isolates were affirmed to harbour Lactobacillus through PCR analysis. Within this subset, 6 isolates (4.96%; CI: 1.84-10.48) were found to possess the plnEF gene. When exposed to Lactobacillus isolates, Salmonella Typhimurium and Salmonella enterica displayed an average maximum zone of inhibition with a diameter measuring 24 mm. In contrast, Escherichia coli exhibited an average minimum zone of inhibition, featuring a diameter of 11 mm. Additionally, the Lactobacillus isolates demonstrated inhibitory zones against Staphylococcus aureus, Klebsiella pneumoniae and Klebsiella oxytoca, measuring 14, 22 and 19 mm, respectively. CLINICAL SIGNIFICANCE: Lactic acid bacteria, particularly Lactobacilli, are plentiful in cow milk and possess broad-spectrum antibacterial properties.

A candidate multi-epitope vaccine against Lumpy skin disease.

Lumpy skin disease (LSD) is a fulminant infectious disease that mostly affects cattle and causes considerable economic loss throughout the globe. This study was conducted to develop a new multi-epitope-based vaccine against LSD that can elicit immunological responses using an in silico reverse vaccinology approach. Initially, three antigenic proteins, protein E5, E3 ubiquitin-protein ligase LAP and 62 kDa protein, were manipulated to recognize potential T-cell and B-cell epitopes. To identify superior epitopes, a variety of bioinformatic techniques including antigenicity testing, transmembrane topology screening, allergenicity assessment, conservancy analysis, and toxicity evaluation were used. Finally, three new subunit vaccines (construct V1, V2 and V3) were developed employing the most effective epitopes, suitable adjuvants, pan HLA DR-binding epitope (PADRE) and linkers. Then, based on the antigenicity, solubility, and validation score of the 3D structures, construct V2 was chosen as one of the best candidate vaccines. The results of the molecular dynamic simulation and disulphide engineering indicated that the vaccine (construct V2) was stable. Additionally, the immunological simulation findings supported the vaccine candidate's ability to trigger humoral and cellular immune responses. Further validation of the proposed vaccine candidate may necessitate additional in vitro and in vivo investigations.