Commensals: Underappreciated Reservoir of Antibiotic Resistance

Abstract

Antibiotic resistance, reported for sulfonamides in the mid-1930s and for penicillins in the 1940s, remains a stubborn quandary. What was once confined mainly to hospitals increasingly involves multidrug resistance that encompasses communities and encircles the globe. Virtually all types of bacterial infections are becoming resistant to antibiotic treatments, according to officials at the Centers for Disease Control and Prevention in Atlanta, Ga. Yet, despite decades of grappling with these issues, we still do not understand fully how genes carrying resistance traits spread, what makes certain species highly promiscuous in transferring those traits, whether there are effective barriers to their spread, and the frequency with which resistance genes move independently or in tandem with other migrating genes.