The carrier strain of S. aureus displays greater growth on NEC than the non-carrier strain. Nasal epithelial cell layers, which had been cultured at the air–liquid interphase in antibiotic-free medium, were inoculated with 38 ± 4 (mean ± SEM) bacteria/well to assess bacterial growth dynamics. The organisms used were S. aureus D30 (SA D30), the carrier strain; S. aureus 930918 (SA 930918), the non-carrier strain; and S. epidermidis (SE), the control strain. The apical surface of NEC layers was washed after 4 hr and bacteria were enumerated and expressed as colony-forming units (CFU). The results represent the mean ± SEM of quadruplicate experiments.