Detection and characterization of fibrous surface appendages in Pseudomonas aeruginosa and Burkholderia cepacia complex bacteria isolated from sputum samples of cystic fibrosis patients by infrared spectroscopy

A. BOSH; A. MIÑAN; V, FANESI; O. M. YANTORNO

Villa General Belgrano

Workshop; I Workshop sobre Pseudomonas y Burkholderia; 2007

Gram negative bacteria express a wide variety of virulence factors including adhesins, lipopolysaccharides, extracelullar proteases,  lipases, and toxins. Particularly, Pseudomonas aeriginosa and Burkholderia cepacia complex (BCC) bacteria produce diferent kind od adhesins as fibrous surfae appendages, whih are important in bacteria.host cell interactions. These appendages are responsible if initialing host tisue colonization through adhesion and of being involved in biofilm formation. Different types of pili, cable pili and flagella, are expressed or co-expressed by most of the gram negative bacteria present in CF patient ´s lung (P. aeruginosa, Burkholderia spp, S. maltophilia and Acinetobacter spp.) Pilus is a polymeric fiber formed by an ordered association of thousands of identical proteinaceous subunits, referred to as pilin. In the last ten years much research attention has been focused on the different glycosylation system of both, pilin and flagelin subunits containing single covalently bound glycans with a possible role in pathogenesis. Most of the different classes de pili and flagellins appendages are difficult to characterize because the experimental procedures for example preparation generally lead to partial or total loss of these appendages. IR spectra of bacteria are highly specific patterns, which allow obtaining information of the overall structural aand biochemical composition of intact BCC bacteria and P. aeruginosa cells recovered from CF patients. For this propose first and second derivatives vector normalized spectra of piliated and non-piliated bacterial cells were compared by means of multivariant statistical analysis. Highly characteristic "spectral markers" of fibrous appendages were found in the carbohydrate region (1200-900 cm-1) and in the "mixed region" (1500-1300 cm-1) of the whole mid-IR spectral range (4000-650 cm-1). FT-IR spectroscopy is easy to implement, allows the analysisi of small quantities of biomass and requieres no consumables or reagents. The methodology developed might provide a simple annd reliable alternative for the evaluation of fibrous appendages in gram-negative bacteria. Although the roles if these different adhesiins in the lung infections of CF patients remain to be clarified, their detection and characterization are important from the epodemiological point of view since they could be associated to virulence, transmission or bacterial spreading.