The Burkholderia cepacia complex is a group of bacteria prevalent in the natural environment that can cause human infections (so-called opportunistic infections) in vulnerable individuals. These microorganisms can colonize a variety of different habitats, including soil (especially at the rhizosphere—the interface between the soil and plant roots), water, polluted environments, and the lungs of patients with cystic fibrosis. Their success as microbial colonizers appears to be dependent on two innate properties: (1) B. cepacia complex bacteria can metabolize an enormous range of organic compounds, and (2) they possess considerable resistance to antimicrobial agents and may synthesize antibiotics of their own.