[Extracellular enzymes of Pseudomonas aeruginosa as virulence factors].

Pseudomonas aeruginosa is an opportunistic pathogen causing a variety of diseases, especially in immunocompromised patients like those suffering from cystic fibrosis (CF) where these bacteria preferentially colonize the bronchopulmonary tract. A high intrinsic antibiotic resistance and its ability to synthesize and secrete numerous different virulence factors are regarded as biological properties contributing to the pathogenicity of P. aeruginosa. Among the virulence factors are many enzymes which have been characterized in detail with respect to their molecular properties. Environmental factors regulating the synthesis and release of extracellular enzymes have been identified as e.g. the concentration of Fe- and PO4-ions, choline, pH, and osmolarity. In addition, low molecular weight substances named autoinducers were identified as regulators which are synthesized by the bacteria. Therefore, P. aeruginosa represents an example for the remarkably complex relationship between pathogenic bacteria and their human host.