Bacterial Suspensions for the Growth of Naegleria Species

Abstract

Amoebae of the genus Naegleria can be isolated and maintained in serial subculture on agar plates spread with suspensions of a variety of Gram-negative bacilli. The concentration of living cells is not critical for optimal growth of amoebae, because bacterial multiplication occurs on the surface of prepared plates during incubation. However, dense bacterial lawns inhibit the migration and growth of amoebae. Suspensions of bacteria which give optimal growth when live are unsatisfactory when killed by heat. An increase in cell density, to match a standard opacity tube, gives amoebic growth which is both typical and reproducible. Standardized suspensions of this type have obvious advantages and can be used for the isolation of Naegleria from cases of human infection and from soil or water. Amoebae of the genus Naegleria can be isolated and maintained in serial subculture on agar plates spread with suspensions of a variety of Gram-negative bacilli. The concentration of living cells is not critical for optimal growth of amoebae, because bacterial multiplication occurs on the surface of prepared plates during incubation. However, dense bacterial lawns inhibit the migration and growth of amoebae. Suspensions of bacteria which give optimal growth when live are unsatisfactory when killed by heat. An increase in cell density, to match a standard opacity tube, gives amoebic growth which is both typical and reproducible. Standardized suspensions of this type have obvious advantages and can be used for the isolation of Naegleria from cases of human infection and from soil or water.