Adhesion to and invasion of pulmonary epithelial cells by the F15/LAM4/KZN and Beijing strains of Mycobacterium tuberculosis.

Globally, specific genotypes of Mycobacterium tuberculosis have been shown to dominate in patients, suggesting that these are more successful pathogens. One such genotype, the F15/LAM4/KZN (KZN) family of M. tuberculosis, has predominated in KwaZulu-Natal, South Africa, since the early 1990s. This strain recently evolved from multidrug-resistant to extensively drug-resistant (XDR). The ability of M. tuberculosis strains belonging to the Beijing family, the KZN family, strains with unique DNA fingerprint patterns and laboratory strains (H37Rv and H37Ra) to adhere to and invade a human alveolar (A549) and a human bronchial (BBM) epithelial cell line was investigated. All strains displayed greater adhesion to and invasion of A549 cells as compared to BBM cells. The Beijing and KZN strains combined showed greater adhesion (28 %) than the unique strains (5 %) (P <0.05). The XDR variant of KZN invaded A549 cells more effectively than the other isolates. These results suggest that the successful spread of the Beijing and KZN strains might be related to their interaction with alveolar epithelium.