Anti-invasion activities of heat-killed lactic acid bacteria isolates against Salmonella enterica serovar Typhimurium

• Main Authors: Anis Syahirah, Saifor Adzuan, Sharifah Aminah, Syed Mohamad, Rashidah, Iberahim, Noor Nadia Syahira, Mohd Kamal, Nurliana, Abd Mutalib, Nur Intan, Hasbullah, Muneer, Alsaydi, Nor'aishah, Hasan, Low, Kheng Oon, Olaide, Olawunmi Ajibola, Rozila, Alias, Maimunah, Mustakim, Azlin, Sham Rambely, Emida, Mohamed, Mohammad Reza, Pourmand
• Format: Article
• Language: English
• Published: Tehran University of Medical Sciences. 2024
• Subjects: QR Microbiology; S Agriculture (General)
• Online Access: http://ir.unimas.my/id/eprint/47312/1/IJM-16-763.pdf; http://ir.unimas.my/id/eprint/47312/; https://ijm.tums.ac.ir/index.php/ijm/article/view/4746; https://doi.org/10.18502/ijm.v16i6.17254

Background and Objectives: The most common cause of severe foodborne salmonellosis is S. Typhimurium. Its interaction with intestinal epithelial cells is little known. Lactic acid bacteria (LAB) were recognized as a prominent probiotic gastroin- testinal microbiota of humans and animals that confer health-promoting and protective effects. This study aims to determine the anti-invasion and antibacterial effects of heat-killed LAB (HK-LAB) isolates against S. Typhimurium towards human intestinal cells. Materials and Methods: 12 HK-LAB isolates from 3 sources of origin (stingless bee, plant, and food) were tested to determine the adhesion of HK-LAB to Caco-2 cells, anti-invasion and antibacterial activities against S. Typhimurium, the adhesion and invasion pattern of S. Typhimurium on intestinal epithelial cells (Caco-2) and assessing the effect of LAB on the S. Typhimurium-host cell interaction. Results: Tairu isolates from food have the highest adhesion rate with 19 ± 1.32/10 Caco-2 cells followed by HK-LAB R-iso- late from plant 17 ± 0.70/10 Caco-2 cells, which is similar to the control (Lactobacillus casei). In the anti-invasion assay, the two HK-LAB isolates that had the strongest adherence to Caco-2 cells, Tairu-isolate inhibited at 78.1 ± 3.06% and R-isolate inhibited at 64.76 ± 9.02% compared to the positive control (63.81 ± 1.15%), which led to increased suppression of S. Ty- phimurium accordingly. Tairu and R isolates were tested for their antibacterial ability against S. Typhimurium. Both R and Tairu isolates displayed strong inhibition zones (27 ± 0.06 mm, 23 ± 0.06 mm) respectively. Conclusion: These findings suggest that the anti-invasion activities of HK-LAB R and Tairu may correlate to their bacteri- cidal effects that serve to protect the host from infection.