Postantibiotic Effect and Delay of Regrowth in Strains Carrying Mutations That Save Proteins or RNA

Abstract

ABSTRACT The postantibiotic effect (PAE) values found for proteinase-defective (Lon − ) Escherichia coli and RNase-defective E. coli exposed to antibiotics were reduced (31 to 60% and 35 to 50%, respectively) in comparison with the control (AB1157), and in the recA13 mutant these values were about 0.4 h with all drugs. Nalidixic acid, under anaerobic conditions, induced no PAE (0 to 0.1 h) in AB1157. A delay in regrowth (0.2 to 0.26 h) was noted with dnaA46 (Ts), gyrA43 (Ts), and gyrB41 (Ts) mutants cultured for 2 h at 43°C. These findings suggest that when proteins and RNA are saved, the cell rapidly resumes the original growth rate.