Persistence and multiplication of obligate anaerobe bacteria in amebae under aerobic conditions

After co-cultivation of Mobiluncus curtisii, an obligate non-sporeforming anaerobe, with free living amebae from the Acanthamoeba spp. under aerobic conditions, internalization, multiplication and persistence of bacterial cells were established for at least 4-6 weeks. Under the same conditions and media without viable amebae, the cells of M. curtisii did not replicate and died in 4-7 days. The infection of amebae occurred with 10 to 100 bacteria per ml of co-cultivation media. In 7-14 days the amount of bacterial cells increased to 1x10(5)-1x10(6) CFU/mL. Electron microscopic examinations revealed bacteria within vacuoles in the amebae and intracellular replication. These results suggest a previously undescribed mechanism for spread, replication and persistence of obligately anaerobe bacteria in the environment and new possible sources, reservoirs and transfer mechanisms of infections caused by obligate anaerobe bacteria.