'Subinhibitory' erythromycin represses production of Pseudomonas aeruginosa lectins, autoinducer and virulence factors

Pseudomonas aeruginosa infection is preceded by selective adhesion of the b acteria to the host target cells via diverse adhesins, including lectins. T his step enables maximal damage to the target host cells by the bacterially secreted injurious toxins and enzymes. The production of both lectins and many of the virulence factors is positively controlled by transcription act ivators including signaling autoinducers (N-acyl-L-homoserine lactones). We show in this communication that erythromycin at subminimal growth inhibito ry concentrations simultaneously suppresses the production of P. aeruginosa hemagglutinins (including lectins), protease, hemolysin and homoserine lac tone autoinducers. The antibiotic-treated bacteria also show reduced virule nce to mice, endorsing clinical observations that indicate the efficiency o f low-dose erythromycin treatment of persistent drug-resistant P. aeruginos a infections.