Heterogeneity of intracellular replication of bacterial pathogens

► Net bacterial growth rate does not necessarily reflect replication rate. ► Bacterial replication can be quantified directly by dilution methods. ► Single cell analysis of intracellular bacterial replication reveals heterogeneity. ► Heterogeneity of intracellular replication is caused by both host and pathogen. ► Non-replicating bacterial subpopulations illustrate the benefits of heterogeneity.