The early antibiotics, developed some 75 years ago, were called “miracle drugs” for the simple reason that diseases that once killed – like the flu or infected wounds – didn't when an antibiotic was administered.
However, as these drugs were used time and again – and perhaps overused – bacteria began to build up a resistance so that the antibiotics were less effective.
That's where we find ourselves now. The Centers for Disease Control and Prevention (CDC) reports at least 2 million people in the U.S. become infected with bacteria that are resistant to antibiotics and at least 23,000 people die each year as a direct result of these infections.
In recent years, however, scientists have concluded that this resistance doesn't just occur inside the body of people taking an over-abundance of prescription drugs. The resistance is also taking place in the environment., such as in wastewater.
Olya Keen, an assistant professor of civil and environmental engineering at UNC Charlotte, has completed research that points a finger at treatments used to clean wastewater that she says may actually be making the problem worse.
She just presented her initial findings at a conference of the American Chemical Society in Denver.
“This research is a small piece of a larger question,” Keen said. “There are varieties of antibiotics found in wastewater, and, at this point, we are just testing one. It is in a class of antibiotics that all have similar compositions, so we anticipate that other antibiotics in this class may respond the same way.”
Chlorine as a change agent
Keen and her students are looking closely at doxycycline, one of the more widely used classes of antibiotics. What they have discovered is that when chlorine used to treat wastewater mixes with doxycycline, it goes through a series of changes and forms new antibiotics.
Keen says wastewater treatment isn't designed to break down antibiotics so the drugs stay in tact. However it does have an unintended effect. Chlorine used to treat the water creates even stronger antibiotics than the original doxycycline.
How do antibiotics end up in wastewater? Just try to keep them out. When someone takes an antibiotic, their body processes it and what's left is passed from the body in human waste.
Disposal is a problem
But the problem is actually deeper than that. When antibiotics expire in both homes and health care facilities, they are often flushed down the toilet and end up in wastewater treatment plants, where they mix with chemicals like chlorine.
“Wastewater tests have found every type of antibiotic known,” Keen said. “The problems antibiotics cause when they are not broken down by treatment is they get into streams, where bacteria are becoming immune to them, and more dangerous, super bug, bacteria can be formed.”
Keen and her students think the answer lies in finding ways to treat wastewater that will effectively break down antibiotics and prevent them from morphing into new forms. The next step in their research will be to treat and test real-world wastewater samples.