Chapter 11 : The Secret Social Lives of Microorganisms

Abstract:

Everything that a cell does within a biofilm can have immediate consequences for its neighbors. This includes the most fundamental action of any microorganisms (microbes): cell division. It is argued strongly-and controversially-that we need to find ways to regulate human population growth in order to avert environmental tragedy, an argument that may be more likely to be heeded now than it was originally. Many pathogens for example bacteria, rely on both quorum sensing and secreted products to inflict harm upon us. This includes the secretion of enzymes that kill host tissue by Salmonella enterica (typhoid fever) and Pseudomonas aeruginosa; toxin production by Bacillus anthracis (anthrax) and Vibrio cholerae; and the widespread production of compounds that break down antibiotics, such as the β-lactamases that destroy penicillin. The chapter focuses on microbial societies and the potential for their own microtragedies. Traditional antibiotics act by killing or stopping cell division, and resistant that can grow in the presence of the antibiotic rapidly replace the original susceptible strains. Resistant mutants that re-evolve secretion can promote the growth of susceptible cells around them. And, more than this, the susceptible cells do not pay the cost of secretion, which can put the resistant strain at a competitive disadvantage. At least in principle, this can slow the rise of antibiotic resistance. By recognizing that microbes rely on both sociality and altruism to cause infection, a novel strategy for treatment is revealed.