Pseudomonas Aeruginosa Colonising Patients with Cystic Fibrosis: Antibiotic Resistance and Growth Conditions Determined by in vivo and in vitro Gene Expression

Background: Pseudomonas aeruginosa is the main pathogen responsible for lung destruction in cystic fibrosis, becoming difficult to eradicate chronic infection. Aims: To describe antibiotic resistance among strains of P.aeruginosa isolated from sputa patients with fibrosis. investigate vivo and vitro expression genes related anaerobic growth. Methods: Sputa (in vivo) vitro) 26 were obtained during 17 months. Genotypes compared by random polymorphic DNA amplification. Expression nirS (anaerobic respiration) mexY (MexXY efflux pump) measured quantitative real time polymerase chain reaction. levels aerobiosis anaerobiosis estimate oxygenation status within lungs. Mutations regulator gene mexZ investigated expressing correlated strains’ resistance. Results: Nine 56 finally analysed. Seven carried a single genotype. Gene was detected all sputa; higher mutations. Multi-resistance frequent. Resistance profiles not always or Comparison indicated mainly aerobic microaerophilic environments sputa. Discussion: e are frequent colonising Presence these mutations correlates increased vitro, but no Results suggest that lungs represent heterogeneous regarding status. This complexity explains mechanisms growth still largely unknown. Conclusions: After many years research few studies, including present, revealed different aspects P. aeruginosa. We determined cut-off discriminate between containing wild type mutated alleles showed comparison allows predict So far, none studies can explain factors influencing behaviour fibrosis making it design new therapeutic strategies.