Effect of a mannose to the interactions between Naegleria fowleri and pathogenic bacteria

Introduction and Aim: In this study, the interaction between pathogenic Naegleria fowleri and pathogenic bacteria such as methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis and Salmonella typhi was analyzed by a monosaccharide of mannose. Moreover, since the form of N. fowleri was found in diseases as cysts, the interaction between cysts and bacteria was analyzed. Materials and Methods: In order to analyze the role of a monosaccharide called mannose in bacterial interaction, the analysis of bacterial association, invasion, and survival for amoeba treated with mannose was performed. N. fowleri trophozoites or cysts were pre-treated with a mannose at a concentration of 10, 50 and 100 mM for 1 hr at 37°C. Results: The MRSA association was hardly suppressed until the concentration of mannose was 50 mM, but its association was reduced by about 168% to N. fowleri trophozoites by 100 mM mannose. Compared to the results for MRSA, the association of E. faecalis had little effect by mannose. Very interestingly, although S. typhi showed much higher invasion than the above MRSA and E. faecalis, it did not survive at all within N. fowleri trophozoites. Ten mM mannose showed a nearly similar 1% association with N. fowleri cyst treated, but not with 50 mM and 100 mM mannose treated N. fowleri cyst at all. Conclusion: The association and invasion of S. typhi was highest for N. fowleri trophozoites and cysts, but the three bacteria did not survive in N. fowleri trophozoites and cysts.