A mouse tumor biofilm model and its use for dissecting in vivo anti-bacterial and anti-biofilm activities of anti-pseudomonas drugs

Chronic Pseudomonas biofilm infections are commonly associated in patients afflicted with cystic fibrosis (CF) leading to high degree of morbidity. In a murine tumor model we demonstrated that P. aeruginosa efficiently colonizes and forms biofilms in cancerous tissue post intra-venous injection. Several non-biofilm forming mutants have been identified and incorporated in the present study. Biofilm formation by wild type strains was evident in electron microscopy and immuno-histological studies. Efficacy of currently available CF infection treatment antibiotics such as ciprofloxacin, colistin and tobramycin were tested in this model. We found out that normal doses of these antibiotics were unable to eliminate wild type P. aeruginosa PA14. However, transposon mutants of P. aeruginosa PA14 (pqsA & Pel A) had strong influence on colonization. Subsequently high doses were effective against wild type P. aeruginosa PA14 biofilms. Overall design: The samples of P. aeruginosa PA14 wild type strain and the transposon mutant of pqsA were analyzed by RNA-seq. The control samples were cultivated in the LB medium until the exponential or stationary growth phase. Four biological replicas were pooled in pairs to get two replicas for RNA extraction, library preparation and sequencing. Tumor samples were collected from mice infected with PA14 wild type or PA14 pqsA transposon mutants. There were four mice per group and the material of each group was pooled to assure sufficient bacterial RNA. The tumor samples were split into two technical replicas for sequencing library preparation. Please note that two groups which each processed data file were generated from are indicated in the file names as following; PA14_exponential growth (PA14_e) PA14_stationary growth (PA14_s) WT_murine tumor cells (PA14_t) pqsA_exponential growth (pqsA_e) pqsA_stationary growth (pqsA_s) pqsA_murine tumor cells (pqsA_t)