A influência do crescimento em biofilme na susceptibilidade a antimicrobianos em Pseudomonas aeruginosa associadas a infecções pulmonares crônicas em pacientes com fibrose cística

Abstract

The chronic pulmonary infection caused by Pseudomonas aeruginosa in patients with cystic fibrosis (CF) is associated with a gradual damage of the pulmonary tissue, resulting the respiratory bankruptcy and death in the majority of the patients. Antibiotic therapy has a important contribution, however the capacity of these microorganisms in persisting in the pulmonary environment after the treatment have been related with their ability biofilm of formation and the resistance to action of antimicrobials in this form of growth. In 40 gotten samples of P. aeruginosa of 20 CF patients with chronic infection: we analyze the capacity of formation of biofilm, compare the minimal inhibitory concentration of five antimicrobials in the two forms of growth, planctonic (MIC) and biofilm (BIC) and made the molecular typing by the PFGE technique. All the samples had revealed capable to form biofilm, being that 47.5% and 45% of them had disclosed moderate and weak capacity, respectively and it did not have significant difference between the morfotypes nonmucoid and mucoid. With it, we compare MICs and BICs verify significant increases for all the antimicrobials. All the samples had been susceptible to the aminoglycosides by the CIM, however in the BIC the resistance levels had been of 92,5%; 85% and 45% for tobramycin, gentamicin and amikacin, respectively. The molecular typing disclosed a great diversity between the samples (27 profiles), since 75% of the patients had revealed colonized for distinct strains. However, some patients had presented samples with the same profile. Correlating the clonal profiles found with the formation of biofilm and the values of the BIC, we verify that did not have association between the clonal profile and phenotypic behavior. Our results show the importance of standardization and implementation of tests in vitro that they can detect these peculiarities and that pulmonary infections for P. aeruginosa represent in trustworther way the true physiopatology them, reflecting of positive form in the medical behavior in front of the patients.