CONICET | Buscador de Institutos y Recursos Humanos

Bacteria belonging to Burkholderia cepacia complex (Bcc) are important opportunistic humanpathogens that colonize lungs of cystic fibrosis (CF) patients producing long-term respiratoryinfections. Among Bcc bacteria, Burkholderia contaminans is the predominant species recovered from sputum samples of these patients in our country (Bosch et al., Martina et al,).CF is characterized by the absence of a functional chloride transporter known as cystic fibrosistransmembrane conductance regulator (CFTR) that is normally present in epithelial 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 precious 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 and, we examined the specific impacts ofiron-III on biofilm formation for 109 clinical isolates sequentially recovered from sputum samples of CF and non-CF patients and 13 environment samples.We reported that B. contaminans is able to attach and grow on abiotic surfaces to form biofilms. Our results show that when the iron concentration is limiting, siderophore biosynthesis increases biofilm formation.Further research is necessary be carried out to address the molecular mechanisms of the ironlimitation on siderophore production and biofilm formation in B. contaminans.Bosch A. et al., J Clin Microbiol. 2008, 46(8):2535-46. doi: 10.1128/JCM.02267-07.Martina P. et al., J Clin Microbiol. 2013, 51(1):339-44. doi: 10.1128/JCM.02500-12.