History has taught us that prior to the discovery of penicillin in the early part of the 20th century, many people died of what are now treatable bacterial infections because there were limited options of available antimicrobial medications. In our current time, we take for granted the plethora of pills, tablets, solutions and ointments available to combat many varieties of bacterial infections.
Since the 1940s until recently, antibiotics have often been used indiscriminately and inappropriately in many cases. Widespread use of antimicrobials has caused many infectious organisms to adapt and build resistance rather than succumbing to the killing effects of antimicrobial medications. The CDC (Centers for Disease Control and Prevention) notes, “Each year at least 2 million human illnesses and 23,000 deaths in the United States are caused by antibiotic-resistant bacteria.”
As it turns out, microbial development of resistance genes to thwart antibiotics is not a new phenomenon; in fact, researchers have found that specific enzymes responsible for some resistance factors date back 2 billion years. But what has spawned the current concern about resistance has to do with the popularity of using antibiotics for just about any sign of a sniffle or cough, or any other problem that is best left for the person’s or animal’s native immune system to deal with.
Antibiotics don’t work against viruses or fungi; only against bacteria. Many antibiotics only target specific bacteria; so, using the wrong antibiotic product does nothing to kill the infectious agent but may instead kill off other commensal (useful) bacteria. In addition, exposure to unnecessary antibiotics potentially stimulates development of resistant genes in bacteria, including those that weren’t the initial target for treatment.
A recent report by the U.S. Food and Drug Administration (FDA) states: “Overuse of antibiotics in both humans and animals helps drive the evolution of resistant bacteria. Bacteria have a natural tendency to mutate and to acquire genes from other bacteria. These changes enable them to resist antibiotics and flourish in environments where antibiotics are used.
As resistance genes move between bacteria, the bacteria themselves spread through soil, water, and wildlife. Over time, with continued antibiotic use, the situation worsens. Scientists are concerned that resistant strains of bacteria could spread globally through travel or trade, including the exchange of foods.”
It is just as important to consider that animals treated with antibiotics are part of the process of microbial resistance. The CDC comments, “Treatment of food-producing animals with antimicrobial agents that are important in human therapy may present a public health risk by the transfer of resistant zoonotic pathogens from animals to humans.” While horses aren’t food-producing animals, overuse in this species contributes to the problem of resistance. If many of our antimicrobials cease to be effective, then we will have nothing left in the medication armamentarium to use to treat human or animal infections when it really matters. This is why we should care.