transplant prognosis, making eradication a priority. Due to antimicrobial resistance seen, novel treatments are required. The objectives of this study were: To determine the sensitivity of clinical strains of B. cenocepacia to manuka honey. To establish whether manuka honey could improve the activity of selected antibiotics against B. cenocepacia. To investigate whether sub inhibitory manuka honey can alter the expression of virulence factors produced by B. cenoepacia. Methods: Modified EUCAST microboth dilution methods were used to determine the MIC of four antibiotics (colistin, tobramycin, ceftazadime and meropenem) and medical grade manuka honey against 17 clinical isolates of B. cenocepacia. The minimum biofilm inhibition concentration was also calculated. Checkerboard methodology was used to investigate interactions between antibiotics and honey. Selected isolates were also tested to see if sub inhibitory levels of manuka honey changed the expression of, haemolysin, protease and pigment production. Results: The majority of isolates showed resistance to the antibiotics, however the MIC for manuka honey for all strains was <20% w/v. Synergy or additivity was seen in all but 4 isolates, the remaining 4 isolates displayed low levels of antagonism. In the isolates tested, reduced pigment production and protease activity were seen on the addition of sub inhibitory honey, however increased haemolysis was observed. Conclusion: B. cenocepacia are susceptible to low concentrations of manuka honey and sub inhibitory concentrations of manuka honey can be used to improve the activity of clinically relevant antibiotics. With further in vivo investigation there is potential for novel formulations to be developed for clinical use. 120 Quorum sensing signals expressed by Burkholderia contaminans clinical isolates recovered from cystic fibrosis patients M. Leguizamón 1 , C. Prieto 1 , P. Martina 1 , B. León 1 , M. Bettiol 2 , C. Figoli 1 , D. Casco 1 , J. Palau 2 , P. Montanaro 3 , L. Cazzola 4 , S. Perez 4 , O. Yantorno 1 , A. Bosch 1 . 1 CINDEFI CONICET-CCT La Plata, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina; 2 Sala de Microbiología, Hospital de Niños “Sor María Ludovica”, La Plata, Argentina; 3 Hospital SantísimaTrinidad de Córdoba, Laboratorio de Microbiología, Córdoba, Argentina; 4 Sala de Bacteriología, Hospital HIGA R. Rossi, La Plata, Argentina Objectives: All Burkholderia cepacia complex (Bcc) species investigated so far employ quorum-sensing (QS) systems that rely on N-acyl-homoserine lactone (AHL) signal molecules to express certain phenotypic traits in a population density-dependent manner and are thought to play important roles in lifestyle changes. It has been reported that Bcc members are able to synthesize C4-HSL to C10-HSL molecules (AHL). The aim of the present work is to get insights into the QS signals expressed by B. contaminans clinical isolates, and analyze the distribution of the expression of the QS signals among isolates recovered from CF patients suffering chronic infections. Methods: A total of 84 B. contaminans clinical isolates recovered from sputum cultures from cystic fibrosis patients attended at 3 CF treatment CF centers in Argentina during a 10-year period was analyzed. The QS signals expression was investigated using biosensors strains, Chromobacterium violaceum. CV026 and VIR07, where the violacein pigment acted as indicators of the induction of these biosensing strains by the action of AHLs. We also used Fourier transform infrared (FT-IR) spectroscopy and HPLC MS/MS-MRM to chemically identify the type of AHL molecule synthesized. Results: The combined use of these technologies allowed us to identify, for the first time, the presence of N-octanoylhomoserine lactone (C8-HSL) as the main AHL expressed by B. contaminans isolates, followed by C10-HSL. In addition, we found that this signals were present mainly in the first isolates recovered along the chronic infections. Conclusion: Our results revealed evidences of the expression of mainly C8-HSL molecules in B contaminans isolates recovered fromsputum samples of cystic fibrosis patients, and a phenotypic adaptation that could contribute to the regulation of virulence along chronic lung infections. 121 Multiple oxidative stress response genes undergo adaptive evolution during chronic CF infection by Burkholderia cenocepacia ST32 J. Nunvar 1 , P. Drevinek 1 . 1 2nd Faculty of Medicine, Charles University, Department of Medical Microbiology, Prague, Czech Republic Objectives: The respiratory tract of CF patients is colonized by diverse bacterial communities. Infections with Burkholderia cenocepacia are regarded most serious, because of their transmissivity and ability to develop into cepacia syndrome (CS), a fatal fulminating pneumonia accompanied with dissemination of bacteria into the bloodstream. The epidemic clone B. cenocepacia ST32 (a member of recA group IIIA) was responsible for a large outbreak in the Czech Republic during the 1990s (>50 CF patients infected in 2001). The objective of this study was to examine genomic evolution of B. cenocepacia ST32 during chronic pulmonary infection and to elucidate possible genetic mechanisms behind their long-term persistence and the ability to progress into CS. Methods: We examined isolates from a total of 8 CF patients who succumbed to CS. 4 isolates were included from each patient, spanning 8 years of infection on avarage and representing various stages of infection including the CS. Next generation sequencing was performed (Illumina, 2× 150 bp) and the reads were mapped onto a complete B. cenocepacia ST32 reference genome. Comprehensive comparative analysis was performed. Results: We revealed an abundance of insertion sequence elements (IS), unprecedented by their high copy numbers when compared to other sequenced B. cenocepacia strains. Furthermore, large-scale deletions were frequently detected, flanked by IS elements. The strongest pattern of parallel evolution was observed for genes directly or indirectly involved in protection against reactive oxygen species (ROS). These mutations were biased towards late-stage isolates. Conclusion: The comparative genomic analysis indicates that evolution towards increased resistance to ROS, which are produced by phagocytes during their respiratory burst, might underlie the progress of chronic pulmonary infection. Compromising the efficacy of ROS-dependent host protective mechanisms may pave the road to the deadly CS. 122 A toxin-antitoxin module could be involved in the emergence of Burkholderia contaminans persister cells M. Leguizamón 1 , B. León 1 , C. Prieto 2 , M. Bettiol 3 , C. Figoli 2 , P. Martina 2 , C. Vescina 4 , F. Rentería 5 , G. Diez 5 , P. Montanaro 6 , F. Vignolles 2 , D. Casco 2 , A. Bosch 2 . 1 CINDEFI CONICET-CCT La Plata, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Chemistry, La Plata, Argentina; 2 CINDEFI CONICET-CCT La Plata, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina; 3 Sala de Microbiología, Hospital de Niños, La Plata, Argentina; 4 Sala de Microbiología, Hospital de Niños “Sor María Ludovica”, La Plata, Argentina; 5 Servicio de Neumonología Hospital de Niños “Sor María Ludovica“, La Plata, Argentina; 6 Servicio de Microbiología, Hospital Santísima Trinidad de Córdoba, Córdoba, Argentina Objectives: Bacterial persistence is the ability of a small subpopulation of bacteria to survive a challenge of high doses of antibiotics without expressing a specific resistance mechanism. It was reported by Van Acker and coworkers that the genomic region BCESM, located in the BcenGI1 i slandof B. cenocepacia J2315, contains an operon (BCAM0257-9) with characteristics suggestive of Toxin-Antitoxin modules which was possible involved in bacterial persistence. We aimed to characterize the BCAM57-59 operon in B. contaminans clinical isolates and evaluate its role in the emergence of persister cells and the establishment of chronic lung infection in patients with cystic fibrosis. Methods: We analyzed 45 isolates recovered from 36 patients colonized by B. contaminans recovered in Argentinan CF centers. Persister were quantified in 24-h biofilms after the exposure to 4xMIC concentrations of ciprofloxacin. The BCESM and the operonwere detected by PCR and sequenced. The expression of BCAM0257-8 was measured by quantitative RT-PCR (qPCR) in sessile and planktonic cells. Results: The average of the percentage of surviving persisters was 8.23 ± 0.26% for B. contaminans isolates recovered from chronic infections in contrast to 1.89± 0.77 of persister for isolates obtained from transient Poster Sessions / Journalof Cystic Fibrosis 16S1 (2017) S63–S174 S96