The Rise of Fluoroquinolone-Resistant Escherichia coli in the Community: Scarier Than We Thought

Physicians have long had reliable anti-biotics for dealing with common com-munity-associated infections caused by Enterobacteriaceae, including Escherichia coli. However, we have had no new clas-ses of antibiotics to treat resistant gram-negative bacilli since the quinolones, a class of antibiotics which is now 50 years old. Unfortunately, the microbes we deal with have not accommodated our lack of innovation by slowing their spread of an-tibiotic resistance. Rates of quinolone resistance among Enterobacteriaceae in the community re-mained low for decades. In the mid-to-late 1990s, resistance rates were <1% [1, 2], and they rose only to 1%–3 % as late as 2008 [3, 4]. However, quinolone resistance rates have skyrocketed in re-cent years, such that now>10%–30 % of community-associated Enterobacteria-ceae are quinolone resistant in many parts of the United States [5–8], and much higher rates (>50%) are seen in other parts of the world [9–11]. This dramatic in-crease in quinolone resistance has been closely associated with spread of a speci-fic clone of E. coli, ST131-H30 [5, 12, 13]. The rise in resistance has necessitated a sea change in medical practice. No longer can doctors “fire and forget ” quinolones at community-associated urinary tract, abdominal, or prostatic infections. Cul-tures and close follow-up are now re-quired. Indeed, quinolones are no longer considered first-line options for treating cystitis [14], and, unfortunately, we have little to replace them with for the treat-ment of pyelonephritis, which continues to be a major cause of morbidity in oth-erwise healthy young women [15]. Bring-ing such patients back to the hospital for intravenous therapy has become com-mon because of inability to treat with any oral agents. How did we get to this point? It is rational to hypothesize that direct exposure of an individual to antibiotics selects for resistant bacteria. Gurnee et al