Persistence of Bacteria in "Protoplast" Form after Apparent Cure of Pyelonephritis in Rats

Appropriate antibiotic treatment of experimental enterococcal pyelonephritis in the rat appears to effect the removal of the infecting organisms from the kidney, as judged by the culturing of kidney homogenates on standard bacteriological media. When the homogenates were cultured on media containing 0.3M sucrose, osmotically stabilized, it was demonstrated that bacteria were present in the "protoplast" form, and that this form persisted in the kidney for at least 13 weeks after therapy.