Corrigendum: Variability of Bacterial Essential Genes Among Closely Related Bacteria: The Case of Escherichia coli - Martínez-Carranza, Enrique; Barajas, Hugo; Alcaraz, Luis-David; Servín-González, Luis; Ponce-Soto, Gabriel-Yaxal; Soberón-Chávez, Gloria (Frontiers in Microbiology, 2018)