Growth kinetics of wild-type, clpB mutant, and complemented clpB mutant strains of L. interrogans. Strains were grown in EMJH, EMJH supplemented with 10% rabbit serum, EMJH supplemented with 10% M199 medium, and diluted EMJH medium, and cultures were incubated at 30°C or 37°C with shaking. Growth was monitored by measuring the OD420.