Cytopathic effect in BHK 21 (C13) cells inoculated with Leptospira interrogans serovar Pomona isolated from a porcine abortion.

BHK 21 (C13) cells inoculated with a wild strain of Leptospira interrogans serovar Pomona isolated from a porcine abortion exhibited cythopathic effect (CPE) consistent in degenerative morphological alterations whereas no cell changes or alterations were observed in cells infected with a non-pathogenic Leptospira biflexa serovar Patoc strain. BHK 21 (C13) cells were seeded on 24 well cell culture plates containing MEM-E medium with 10% fetal bovine serum and no antibiotics; 5 x 104 cells per ml were poured into each well. Cell cultures were infected with one milliliter of a suspension from each separate strain containing 1 x 107 leptospires/ml. Cells were subsequently incubated at 37 °C in a 5% CO2 atmosphere and fixed with methyl alcohol at 24 and 48 h pi. Cell morphology and leptospiral CPE were microscopically assessed in May GrünwaldGiemsa stained smears. In this study, several CPE caused by a wild strain of L. interrogans serovar Pomona were observed at 24 h pi: ballooning, loss of cell structure, vacuolization and lysis (Figures 1 and 2). This fact demonstrated the ability of leptospires to produce cell damage. No changes were observed in BHK 21 (C13) cells infected with a non-pathogenic L. biflexa serovar Patoc strain (Figure 3). Origin of Leptospira strains: La-