CONICET | Buscador de Institutos y Recursos Humanos

Bacteria belonging to Burkholderia cepacia complex (Bcc) are importan opportunistic human pathogens that colonize lungs of cystic fibrosis (CF) patients producing long-term respiratory infections. Among Bcc bacteria, Burkholderia contaminans is the predominant species recovered from sputum samples of these patients in our country. CF is characterized by the absence of a functional chloride transporter known as cystic fibrosis transmembrane conductance regulator (CFTR) that is normally present in epitelial cell membranes, resulting in multiple organ system impairment. The respiratory tract is one of the most affected systems in CF patients where the defect in ion transport results in accumulation of highly viscous mucus. This environment is precios for the airway microbial colonization. In this context, biofilm formation from colonizing bacteria is considered an important virulence factor. Knowing the elements that stimulate or affect a productive establishment of a biofilm is crucial to learn how to control the infection. In the present investigation, we assessed the influence of siderophore on biofilm formation of B. contaminans isolated. Using defined iron limited and iron-rich minimal medium, we examined the specific impacts of iron-III on biofilm formation for 109 clinical isolates sequentially recovered from sputum samples of CF and non-CF patients and 13 environmental samples. We reported that B. contaminans is able to attach and grow on abiotic surface to form biofilms. Our results show that when the iron concentration is limiting, siderophore biosynthesis increase biofilm formation. Further research is necessary be carried out to address the molecular mechanisms of the iron limitation on siderophore producton and biofilm formation in B. contaminans.