Detection of Burkholderia cepacia epidemic strain marker (BCESM) and the cable pilin subunit gene (cblA) in Burkholderia contaminans local isolates

CLAUDIA PRIETO; PABLO MARTINA; MARIANA LEGUIZAMÓN; MARÍA LAURA CAZZOLA; FERNANDO RENTERÍA; NÉSTOR BITAR; ALEJANDRA BOSCH; OSVALDO YANTORNO

Mar del Plata

Congreso; X Congreso Argentino de Microbiología General SAMIGE; 2014

Sociedad Argentina de Microbiología General SAMIGE

Pulmonary infection with bacteria belonging to Burkholderia cepacia complex species (Bcc) in cystic fibrosis (CF) patients are usually chronic, resistant to antibiotic therapy and associated with increased morbidity and mortality. Previous studies identified transmissibility markers in Bcc bacteria, which were associated with certain epidemic strains, having an increased ability to spread. These markers included the cable pili (cblA) gene (Sajjan et al., 2008) and the B. cepacia epidemic strain marker (BCESM) which is part of a genomic island encoding genes linked to metabolism and virulence such as quorum sensing signals (AHLs). The prevalence of infection in CF population world while has shown that B. multivorans, B. cenocepacia, and B. cepacia are the most predominant Bcc pathogens, causing on average 80% of the Bcc infections. However, in a previous study, we demonstrate that in Argentina 8, out of the 18 Bcc species could be recovered from CF patients, with a remarkably high representation of B. contaminans, detected in 60% of the CF patients analyzed (Martina et al., 2013). Thus, despite the implementation of strict infection control protocols, B. contaminans species have been recovered from both CF and non-CF patients, industrial products, and environmental samples. In order to analyze some virulence factors and get insights into the identification of possible problematic strains and assist in the diagnosis and management of B. contaminans infections in CF patients, in the current study we investigated the presence and distribution of transmissibility markers as well as the association with the presence of QS signals in B. contaminans isolates recovered from CF patients, non-CF patients and environmental samples. A total of 93 B. contaminans isolates recovered in the period 2003-2013 from different regions of Argentina were analyzed. This collection consisted in 72 clinical isolates belonging to CF patients (63 children and 9 adults), 12 clinical non-CF isolates and 9 environmental samples. Isolates were characterized by recA-PCR-RFLP and identified by sequencing of the recA gene. BCESM and cblA gene were detected by PCR using specific primers. QS signals were identified by means of AHLs biosensors. Our results showed that 82,6% of the isolates recovered from CF patients carried the BCESM while, in only 10,9% and 6,5% of the isolates recovered from non-CF patients and environmental samples respectively the BCESM was detected. On the other hand, in none of the B. contaminans isolates the cblA gene could be detected. In order to study the distribution of the BCESM along the 10 years of our survey, we analyzed the presence of this marker in CF children patients. It is important to note that the presence of the QS signals was positively correlated with the incidence of the BCESM in the population analyzed in this work.