Inhibitory effect of Lactobacillus acidophilus on Helicobacter hepaticus in vitro

Abstract

Helicobacter hepaticus and Helicobacter pylori both belong to Helicobacter species. Strains of Lactobacillus acidophilus, including L4 and L6, have shown significant inhibitory effects on H. pylori. Based on this phenomenon, we aim to investigate the inhibitory effect of L. acidophilus on H. hepaticus. Both standard and isolated H. hepaticus strains were grown under microaerophilic conditions at 37 °C in the presence of L. acidophilus supernatant, or lactic acid. The diameters of the inhibition zones were measured on the solid culture media. In liquid culture, the cell concentrations were measured and the urease activity was determined by phenol red staining. Sixteen strains of L. acidophilus isolated from human feces (named as L1-L16) showed anti-H. hepaticus effects. Two of them (L4 and L6) exhibited the most apparent effects on H. hepaticus inhibition. The L. acidophilus supernatant of L4 and L6 significantly increased the diameters of the inhibition zones compared with that of the lactic acid control (P < 0.05). The inhibitory role of L. acidophilus supernatant was independent of the pH value of solution (P > 0.05). Moreover, in liquid culture, L. acidophilus supernatant significantly reduced the cell growth rate and the urease activity of H. hepaticus cells in a time-dependent pattern (P < 0.05 compared with lactic acid control). No obvious difference was observed between the standard and isolated strain of H. hepaticus (P > 0.05). Our results indicate that L. acidophilus can decrease the viability and urease activity of H. hepaticus in vitro and this inhibition is independent of pH levels. This provides evidence for developing novel approaches for the prevention and treatment of H. hepaticus infection.

Oral Immunization with Recombinant Lactobacillus acidophilus Expressing the Adhesin Hp0410 of Helicobacter pylori Induces Mucosal and Systemic Immune Responses

“…The reason is likely to be that L. acidophilus itself may also be able to improve the degree of inflammation caused by H. pylori infection. Possible mechanisms for this are as follows: (i) L. acidophilus may adhere to and colonize the gastric mucosa in ad- (46)(47)(48). Compared with traditional vaccine vectors, LAB have several advantages, including being safer and nontoxic, being able to adhere to and colonize the respiratory tract, digestive tract, and other mucosal epithelial cell layers, and functioning to express and to secrete heterologous proteins and to induce strong mucosal immune responses (29,49).…”

Lactoferrin Adsorbed onto Biomimetic Hydroxyapatite Nanocrystals Controlling - In Vivo - the Helicobacter pylori Infection

“…The probiotic Lactobacillus paracasei was obtained from by the Department of Microbiology of the University of Naples Federico II. Cell free supernatant (CFS) of Lactobacillus paracasei was obtained as described previously [ 21 – 22 ]. The supernatant was tested to identify the presence of bacteria by plating serial dilutions on MRS Agar (Oxoid England).…”

“…The supernatant was tested to identify the presence of bacteria by plating serial dilutions on MRS Agar (Oxoid England). No bacteria were identified after filtration [ 21 – 22 ].…”

Growth kinetic models of five species of Lactobacilli and lactose consumption in batch submerged culture

“…A common feature of these microorganisms is their antagonistic activity against some pathogens such as salmonella spp., Escherichia coli , Listeria monocytogenes , Clostridium perfringens and Helicobacter hepaticus 6, 7, 8, 9, 10, 11. The capability of L. plantarum and L. reuteri in phytic acid hydrolysis is valuable in bread processing technology 12 .…”