DETECTION OF HIGH LEVELS OF BURKHOLDERIA CONTAMINANS PERSISTER CELLS IN CYSTIC FIBROSIS PATIENTS WITH CHRONIC LUNG INFECTION

CLAUDIA PRIETO; JULIANA PALAU; PATRICIA MONTANARO; CECILIA FIGOLI; PABLO MARTINA; FERNANDO RENTERÍA; BELTINA LEÓN; OSVALDO YANTORNO.; MARIANA LEGUIZAMÓN; MARISA BETIOL; GRACIELA DIEZ; DANIELA CASCO; ALEJANDRA BOSCH

Orlandp

Conferencia; North American Cystic Fibrosis Conference; 2016

North American Cystic Fibrosis Foundation

Among the Burkholderia cepacia complex species, B. contaminans represents the most frequently recovered from patients with cystic fibrosis (CF) in Argentina (1). Although for some patients B. contaminans respiratory tract infection is transient, its acquisition most typically results in a chronic infection with a gradual decline in lung function (2). It was recently reported for B. cenocepacia J2315 (belonging to the ET12 lineage) that the ?Burholderia cepacia epidemic strain marker? (BCESM) genomic region located on the genomic island (GI), BcenGI11, contains an operon (BCAM0257-8-9) possible involved in persistence, quorum sensing expression, and virulence (3). We here aimed to study a possible relation between persistence and establishment of B. contaminans chronic infection, and the presence of genes associated to the genomic island BcenGI11, which was not reported for this species, so far. For this purpose, we analyzed 145 B. contaminans isolates recovered from 52 patients attended in 3 different CF reference centers of Argentina, between 2004-2015. The BCESM and the BCAM0257-8-9 regions were detected by PCR -using B. cenocepacia specific primers- and sequenced. Persister cells in 24-h old biofilms exposed to ciprofloxacin concentrations of 4 × the MIC was quantified, and QS signals expression was analyzed by means of AHLs biosensors. Our results showed that the 94.7 % of the chronic infected patients (36 out of 38) and the 28.6 % of the patients with transient infections (4 out of 14 patients) harbored both the BCESM and the BCAM257-9 regions. Sequence analysis showed that the amplification products of these regions had an identity of 93 and 95 % with those of B. cenocepacia J2315, respectively. The percentage of surviving persisters was between 5 and 10 % for B. contaminans isolates carrying the operon in contrast to less than 2% for isolates for which did not. QS signals expression was also positively correlated the presence of the BCESM genomic region. These results showed that, the presence of the operon contained in the BCESM region might be responsible for the difficulties in the eradications of B. contaminans chronic infection