Burkholderia cepacia epidemic strain marker (BCESM) detected in Burkholderia contaminans isolates recovered from cystic fibrosis patients could be associated with transmissibility and persistence

MARIANA LEGUIZAMÓN; C. PRIETO; P. MARTINA; F. VIGNOLLES; M. BETTIOL; P. MONTANARO; M.L. CAZZOLA; S. S. PÉREZ; O. YANTORNO; A. BOSCH

Córdoba

Congreso; XI Congreso Argentino de Microbiología General; 2015

Sociedad Civil de Microbiología General (SAMIGE)

Burkholderia cepacia complex (Bcc) species have emerged as highly problematic human pathogens causing severe respiratory infections in cystic fibrosis (CF) patients. Among the 20 Bcc closely related species currently described, B. multivorans, B. cenocepaci, and B. cepacia have been reported to be the most frequently recovered species worldwide. Nevertheless, in a local epidemiological study we found a remarkable high representation of B. contaminans arising to almost 60% in CF patients (1).Although for some patients only a transient respiratory tract infection may occur, the acquisition of B. contaminans most typically results in a chronic infection with acute exacerbations and a gradual decline in lung function (2). The BCESM genomic region, part of a genomic island BcenGI11, was encountered in all the B. cenocepaciastrains belonging to the ET12 lineage which have caused major outbreaks in CF patientsin Canada, the UK and other European countries (3). Besides, in B. cenocepacia and other species of the complex the BCESM positive strains have generally been associated with high transmissibility, virulence and mortality (3). Additionally, it was recently reported for the B. cenocepacia J2315 (belonging to the highly transmissible ET12 lineage) that this genomic marker contains an operon associated with quorum sensing (QS) signals expression, and is involved in persistence, biofilmformation and virulence (Van Acker et al., 2014). The objective of this work was to analyze the prevalence of B. contaminans clinical isolates harboring the BCESM genomic region and investigate its possible association with transmissibility and/or persistence.A total of 107 B. contaminans isolates recovered from sputum samples of cystic fibrosis patients attended in Argentina were analyzed. BCESM was detected by PCR using B. cenocepacia specific primers. For the BCESM genomic region sequencing analysis specific primers were designed. QSsignals were identified by means of AHLs biosensors.Our results showed a high prevalence of clinical isolates harboring the BCESM in both, isolates belonging to first infections (63%) and isolates recovered from CF patients with chronic lung infection 62 %). We found that in the population here analyzed the presence of the BCESM genomic region was positively correlated to the expression of QS signals. These results together with the BCESM sequence analysis showed that although B. contaminas local clinical isolates seem to shear some of the characteristics of B. cenocepaciastrains belonging to the ET12 lineage, more studies are needed to understand its high transmission and persistence in CF local patients.(1) Martina et al. 2013, J Clin Microbiol 51: 339-344(2)Martina et al. 2014, Internat J Med Microbiol 304:1182?1191(3) Van Acker et al. 2014, Future Microbiol 9: 845?860(4) Mahenthiralingam et al. 1997, J Clinical Microbiol 5:808-16