PGP and infection: To assess the contribution of various virulence factors of N. meningitidis to the potential disruption of P-gp activity during infection, we next examined several isogenic mutants of strain MC58, including an isogenic capsule-deficient mutant (N. meningitidis MC58∆csb), an isogenic non-piliated mutant (N. meningitidis MC58∆pilE), and an isogenic mutant lacking outer membrane adhesion protein OpcA (N. meningitidis MC58∆opcA), each representing important virulence factors involved in the interaction of N. meningitidis with BECs during infection (Fig. 3A) [24, 30].