Mechanisms of antibiotic resistance in Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a notoriously difficult organism to control with antibiotics or disinfectants1. Recent reports on the antibiotic sensitivity patterns of P. aeruginosa in the UK have highlighted the problem of antibiotic resistance in cystic fibrosis (CF) strains in comparison with other hospital isolates2,3. Table 1 summarizes the current position in which the resistance rates of P. aeruginosa strains from CF patients are all significantly higher than those from non-CF patients. Extensive use of these antibiotics to treat P. aeruginosa in CF has generated the selective pressure to encourage resistance development. Why is P. aeruginosa resistant to antibiotics and how can it become more resistant following exposure to antibiotics? Its general resistance is due to a combination of factors: