Enterococcus faecalis pheromone-responding plasmid pAD1 gives rise to an aggregation (clumping) response when cells are exposed to subinhibitory concentrations of chloramphenicol, erythromycin, or tetracycline

The Enterococcus faecalis conjugative cytolysin plasmid pAD1 encodes a spec ific aggregation (clumping) response to the peptide sex pheromone cAD1 secr eted by plasmid-free strains. Here it is shown that, in the absence of cAD1 , exposure of E. faecalis cells harboring pAD1 to subinhibitory concentrati ons of chloramphenicol, erythromycin, or tetracycline also results in an ag gregation response that appears related to a stress-sensitive mechanism ass ociated with a component of the pheromone response. (C) 1999 Academic Press .