P239 Bacterial interactions in Pseudomonas aeruginosa and Achromobacter xylosoxidans co-cultures

Loss of microbial diversity in conjunction with chronic Pseudomonas aeruginosa colonisation is strongly correlated progressing lung injury cystic fibrosis. The persistence can be explained by mechanisms such as extensive antibiotic resistances and a high capacity to form biofilm. Another factor its ability exert antagonism against other bacteria, e.g. Staphylococcus aureus. In this study, we are investigating the interactions between P. Achromobacter xylosoxidans, two gram-negative species similar that frequently found co-isolated sputum cultures. A recent study showed they equally disease progression, but patients both infections had worst outcomes. We want investigate whether may involve synergistic effect or if co-infections where only one pathogen persists over time due antagonism. Two CF isolates were selected based on low inhibition S. These grown liquid medium equal amounts until stationary phase. DNA was extracted bacterial amount quantified using qPCR housekeeping genes, expressed % monoculture. Six studied 3 longitudinal pairs. One isolate able grow well aggressive Pseudomonas, even better than less-competitive isolate. This compete presence diminished corresponding from same patient after years colonisation, absence iron. vary greatly isolates. continuing studies, will further characterise identify factors favour coexistence genomic transcriptomic analysis.