Adherence ability of Pseudomonas aeruginosa strains isolated from patients with cystic fibrosis to two different epithelial cell lines

The ability of 59 wild-type strains of Pseudomonas aeruginosa to adhere to the HeLa and Buffalo Green Monkey Kidney (BGMK) cells was investigated. Twenty strains were isolated from sputa of cystic fibrosis patients, while 19 strains were isolated from tracheal aspirates and 20 from bronchial secretions of patients without cystic fibrosis, and they were used as a control group of strains. The statistically significant difference between adherence ability of strains was observed (p < 0.01). While most of the tracheal and bronchial isolates were hyperadhesive (51-110 bacteria per cell) most of the cystic fibrosis isolates adhered poorly to the HeLa and BGMK cells (1-10 bacteria per cell). The bacterial binding to the cells was blocked when bacteria were incubated at 80 degrees C for 20 min before the adherence assay. These results indicate that alginate is not involved in the adherence of P. aeruginosa to the used epithelial cell lines, and, because of that, mucoid strains isolated from persistently colonized cystic fibrosis patients showed poor adherence ability.