Distribuição de fatores de virulência de acordo com o perfil de formação de biofilme em isolados clínicos de Pseudomonas aeruginosa

Abstract

Pseudomonas aeruginosa are Gram-negative bacteria present in different niches, but capable of colonizing and infecting organisms. They are considered opportunistic pathogens frequently isolated in nosocomial environments and reported in a variety of acute and chronic infections, mainly in immunocompromised patients. This bacterium expresses several virulence factors that contribute to pathogenesis during its infectious process, including the ability to form biofilms. In this context, the present work evaluated the relationship between the expression of virulence factors and biofilm formation of clinical isolates of P. aeruginosa. For this, the biofilm formation profile, swimming and swarming motility, alkaline protease, hemolysins, phospholipase C, lipases and pyoverdin were evaluated from a total of 32 P. aeruginosa, of which 30 were isolated from secretions of tracheostomized children and from corneal secretions from hospitalized patients and 2 were American Type Culture Collection standard strains – P. aeruginosa ATCC 27853 and ATCC 9027 from the Bioassay Laboratory collection. The clinical isolates were kindly provided by the Microorganism Biotechnology Laboratory of the Institute of Tropical Pathology and Public Health at the Federal University of Goiás. All bacteria were able to form biofilms and 6 (18.75%) strains were classified as strong biofilm producers, 17 (53.13%) as moderate and 9 (28.12%) as weak biofilm producers. Regarding the other virulence factors, all 32 strains produced pyoverdine, 29 (90,62%) produced lipase in medium B (tributyrin), 30 (93.75%) produced hemolysin, 29 (90.62%) produced alkaline protease, 24 (75.00%) phospholipase C, 21 (65,62%) lipase in medium C (rhodamine B) and 13 (40,62%) lipase in medium A (tween 80). The distribution of virulence factors in relation to biofilm formation did not show significant differences between the three classified groups (p < 0.05), but a slight increase in the expression of virulence factors was observed in the group of strong formers in relation to the others, being that the production of hemolysin, alkaline protease, lipase in medium B and pyoverdine was detected in all the strongly biofilm forming pseudomonas. Although no significance was detected between the correlation of virulence factors and biofilm formation, we believe that further studies with a greater number of strains may be necessary to confirm this finding.