INFLUENCE OF PSEUDOMONAS-AERUGINOSA EXOPRODUCTS ON VIRULENCE FACTOR PRODUCTION IN BURKHOLDERIA-CEPACIA - EVIDENCE OF INTERSPECIES COMMUNICATION

The effect of concentrated cell-free extracellular material from stati onary-phase cultures of Burkholderia cepacia 10661 and Pseudomonas aer uginosa PAO1 on virulence factor production in B. cepacia was assessed . While increasing concentrations of the B. cepacia exoproduct caused a slight increase in siderophore, lipase, and protease production in t he producing organism, a significant increase in productivity was obse rved for all three virulence factors with the addition of the PAO1 exo product. Moreover, the addition of the exoproduct from a strain of P. aeruginosa producing reduced amounts of autoinducer caused only a slig htly greater response than that of the control, Both B. cepacia 10661 and P. aeruginosa PAO1, along with two matched clinical isolates of bo th organisms obtained from a cystic fibrotic patient, were shown to pr oduce variable amounts of three different types of autoinducer. The po tential for interspecies signalling in microbial pathogenicity is disc ussed.