A hundred Pseudomonas aeruginosa strains from several clinical specimens from five hospitals in São Luís-MA were evaluated for biofilm production, prevalence of the gene algD, adhesion to HEp-2 cells and antimicrobial susceptibility. The most affected clinical specimens and hospital sectors were also evaluated. Most isolates were obtained from the tracheal aspirate (21.0%) and the most affected hospital sector was the ICU (43.0%). The antibiotics with the highest sensitivity rate were amikacin, piperacillin/tazobactam, fluoroquinolones, gentamicin and meropenem and the ones with the highest resistance rate were aztreonam, ceftazidime and cefepime. All samples were sensitive to polymyxin B. In relation to the expression of the gene for ESBL, 50.0% (17/34) of the multiresistant strains showed the enzyme TEM. Most strains showed high hydrophobicity and 96% of the isolates produced biofilm on a polystyrene microplate, 52% were capsule producers, 19% showed mannose-sensitive fimbriae and 39% expressed the gene algD. We observed adhesion to HEp-2 cells and to the coverslip. These factors may be reported in the pathogenesis of this bacterium, what represents a potential risk for colonization of medical devices which favor the establishment of chronic nosocomial infections.