Growth study of Strep. mutans strains UA159, TW14D, TW251 and TW314 in BHI broth in a 42 °C water bath (open symbols) and a 37 °C aerobic chamber with 5 % CO2 (closed symbols). While no significant differences were observed between the strains at 37 °C, severe defects in growth rate of TW14D (□) and especially TW314 (▵) were measured during growth at 42 °C, when compared to UA159 (◊). The data presented here are representative of three independent experiments. ON, Overnight.