Group A streptococcal L forms. I. Persistence among inoculated mice.

L forms induced from two strains of group A Streptococcus were inoculated intraperitoneally and intravenously into conventional and germ-free mice. After intravenous injection, streptococcal L forms disappeared very quickly from the blood, whereas, after intraperitoneal injection, it was possible to isolate them as long as 25 days after inoculation. Observations suggest that a certain degree of reversion to a bacterial form may occur spontaneously in animals.