Identification of listeriosis and potency of antimicrobial probiotics by in vitro test on beef cattle

The study aimed to identify listeriosis in cattle by using conventional and molecular diagnostic methods and to test the implementation of probiotics as inhibitors of listeriosis in cattle in vitro. Laboratory tests conducted to diagnose listeriosis and antimicrobial activity. Parameters included the color, shape, size, and surface of the colony, shape, and gram staining. Molecularly, the observed variable: the size of the molecular weight of PCR products. Results showed that the conventional method diagnoses of Listeria monocytogenes isolate having the green colonies, round shapes, 1 mm size, shiny convex surfaces, gram-positive, 1-2 μm × 0.5 μm short stem and Listeria innocua isolate had white colonies, round shape, slippery surface, 1-2 mm size, gram-positive, short stem size 0.3 - 0.5 μm. Additionally, conventional method diagnosis found 12 listeriosis isolates [37.5%]. Molecular diagnosis using specific PCR to Listeria monocytogenes and Listeria innocua, produce a product with 1500 bp in size and found in 8 listeriosis isolates [25%]. The highest inhibition zone was obtained from Weissella paramesentroides LAB strain 259 with 22 mm clear zone diameter in the Listeria monocytogenes test bacteria and LAB Pediacoccus pentosaceus CTSPLI strain with a 24 mm clear zone diameter in the Listeria innocua test bacteria. In conclusion, probiotics can inhibit the growth of Listeria monocytogenes and Listeria innocua from uterine isolates.