MODIFICATIONS OF BURKHOLDERIA CONTAMINANS LIPOPOLYSACCHARIDE IN ISOLATES RECOVERED DURING CHRONIC LUNG INFECTION OF PATIENTS WITH CYSTIC FIBROSIS

DANIELA CASCO; CLAUDIA PRIETO; HUGO VALDEZ; LAURA BELTINA LEON; YANINA LAMBERTI; MARISA BETTIOL; CAROLINA VITA; CECILIA BEATRIZ FÍGOLI; MARÍA EUGENIA RODRIGUEZ; OSVALDO YANTORNO; ALEJANDRA BOSCH

Congreso; XVI CONGRESO ARGENTINO DE MICROBIOLOGÍA GENERAL SAMIGE; 2021

Burkholderia contaminans is one of the most prevalent species of the Burkholderia cepacia complex (Bcc) recovered from patients with cystic fibrosis (CF) in Argentina. While infections by B. contaminans could be transient, in most cases it results in a chronic lung infection. Colonization with these bacteria is associated with a high difficult eradication, accelerated decline in lung function, and a significant health risk to CF patients. The lipopolysaccharide (LPS) is a central component of the outer membrane in Gram-negative bacteria that plays a key role in interactions between the pathogen and the host´s immune system. Recently, it was reported that both B. cenocepacia and B. multivorans LPS lost the OAg during chronic infection, while B. contaminans exhibited a stable OAg expression even during 10- or 15-year infections. We aimed to study the features of the LPS in isolates recovered along with the chronic infection in patients with CF, and elucidate a possible correlation with bacterial phenotypes and persistence in the host.We analyzed the two prevalent clones of B. contaminans in Argentina with sequence types ST872 and ST102, recovered from 8 patients with CF who have been attended at the Hospital de Niños de La Plata in the last 14 years (the initial and last available isolates from each patient). The band profile of purified LPS was analyzed by SDS-PAGE together with several phenotypic characteristics such as motility, hemolysis-proteolysis, biofilm formation capacity, and invasion in A549 cells. All the first and last ST102 isolates showed the same LPS structure presenting the OAg. In contrast, first ST872 isolates presented different LPS structural characteristics with OAg with different lengths and last isolates showed changes or even the loss of the O-Ag particularly in those patients with more than 4 years of B. contaminans chronic infection. By Principal Component Analysis we could observed that the modifications in LPS structure of ST872 isolates was associated with changes in the expression of virulence factors, such as swimming and swarming motility. Interestingly, ST872 isolates that showed a modified OAg pattern demonstrated an increased invasion in A549 cells.In fact, it is still not clear why different B. contaminans clones may differ in their LPS structure and evolution along with the chronic infection. Although for some clones, as ST102 and the previously published ones (cit) the LPS structure is highly conserved, we here demonstrated that for other clones, such as ST872, LPS structure presented changes and even the loss of OAg during the chronic infection. This was also correlated with certain bacterial phenotypes and associated with their persistence in the host.