An unwanted effect of antibiotic treatment is promotion of antibiotic resistance through the dissemination of resistance genes and the selection of resistant subpopulations of bacteria. Prudhomme et al. discovered that the stress of exposure to antibiotics triggers competence ("parasexuality") in Streptococcus pneumoniae, not only enabling the acquisition of new antibiotic resistance genes but also permitting the acquisition of virulence determinants. Natural transformation is widespread--it has been observed in about 50 different species of bacteria. The discovery that it can be stimulated by antibiotics has significant implications for strategic antibiotic development.
M. Prudhomme, L. Attaiech, G. Sanchez, B. Martin, J.-P. Claverys, Antibiotic stress induces genetic transformability in the human pathogen Streptococcus pneumoniae. Science 313, 89-92 (2006). [Abstract] [Full Text]