TOXIN-ANTITOXIN MODULE COULD BE INVOLVED IN THE EMERGENCE OF BURKHOLDERIA CONTAMINANS PERSISTER CELLS

PRIETO, CLAUDIA; MARTINA, PABLO F.; MONTANARO, PATRICIA; BOSCH, ALEJANDRA; LEÓN, BELTINA; FIGOLI, CECILIA; RENTERÍA, FERNANDO; CAZCO, DANIELA; LEGUIZAMÓN, MARIANA; BETTIOL, MARISA; VESCINA CECILIA; VIGNOLLES, FLORENCIA

Sevilla

Congreso; 40th European Cystic Fibrosis Conference ECFC 2017; 2017

European Cystic Fibrosis Society

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 infections. All chronically infected patients and 20 % of the patients with transient infections harbored this TA module. Sequence analysis of both regions had more than 95 % of identity with those of B. cenocepacia J2315. The expression of the BCAM257-58 genes were confirmed by qPCR in the isolates that showed the higher levels of persister cells Conclusion: The operon BCAM 0257-9 may play a role in the rate of the emergence of persistor cells and could be associated to the difficulties in the eradications of B. contaminans chronic infection. The detection of this TA module in the first isolates recovered from patients could be used as an indicator of risk of acquiring of a chronic infection.