Key takeaways

Broad-spectrum antibiotics, including clindamycin and fluoroquinolones, are identified as the most significant contributors to C.Diff infections by killing beneficial gut bacteria.
Patients 65 or older, particularly those in healthcare settings, are at the highest risk for C.Diff infections due to their exposure to broad-spectrum antibiotics.
Antibiotics less likely to cause C.Diff include azithromycin, clarithromycin, doxycycline, erythromycin, fidaxomicin, minocycline, and metronidazole.
Effective C.Diff treatment requires specific antibiotics like oral vancomycin, highlighting the importance of targeted antibiotic use and stewardship programs to reduce unnecessary prescribing.

The introduction of antibiotics to cure infections undoubtedly revolutionized medicine over the past century. But some of these “wonder drugs,” as they were once called, can also leave the body vulnerable to an infectious disease called C.Difficile.

What is C.Diff?

Clostridioides difficile, formerly known as Clostridium difficile, or C.Diff, is a contagious bacteria that can cause severe diarrhea. Other common C.Diff symptoms include fever, nausea, loss of appetite, and abdominal pain.

It’s estimated to cause almost 500,000 illnesses in the United States and 15,000 deaths each year, according to the Centers for Disease Control and Prevention. It is currently classified by the CDC as an “Urgent Threat”—the Centers’ highest threat level—to human health from an infectious pathogen in the U.S. (The CDC plans to release an updated report regarding this data in fall 2019.)

Which antibiotics cause C.Diff?

So how exactly does antibiotic usage make one susceptible to a life-threatening disease like C.Diff? When you take an antibiotic, it works to kill a bacterial infection in your body. In the process, these drugs can also destroy the healthy bacteria that keep invaders like C.Diff in check. It’s important to note, not all antibiotics cause C.Diff, and not everyone has the same risk. Although almost any antibiotic can cause it, the worst culprit, in this case, is often broad-spectrum antibiotics. Those most at risk are patients 65 or older who have been in a healthcare setting, such as a hospital or nursing home.

“Broad-spectrum antibiotics have activity against a [large] range of bacteria that reside in the gut,” explains Dr. Hana Akselrod, assistant professor of medicine in the Division of Infectious Disease at the George Washington School of Medicine and Health Sciences. “It’s very important to have a healthy and diverse population of these bacteria.” When people are given broad-spectrum antibiotics, “their gut bacteria are depleted,” thereby allowing for a “pathogenic species,” such as C.Diff, to “essentially create overgrowth of aggressive bacteria that produce toxins that damage the bowel and create very severe illness.”

Erika Prouty, Pharm.D., former adjunct professor at Western New England University College of Pharmacy in Springfield, Massachusetts, breaks it down further: Broad-spectrum antibiotics can be potentially threatening for patients because they “not only target the bad bacteria we’re trying to eradicate, but they also kill a lot of the good bacteria that’s in our digestive system.”

Both Dr. Akselrod and Dr. Prouty identify clindamycin and fluoroquinolones as some of the worst offenders. The list of antibiotics that could cause C.Diff includes:

“It’s unfortunate,” says Dr. Akselrod, “because those antibiotics are in wide use for everything from pneumonia to urinary tract infections.” The other issue is the necessity of certain IV antibiotics regularly used by physicians in hospital emergency rooms, which also fall under the “broad-spectrum” umbrella. These drugs include:

piperacillin/tazobactam (Zosyn)
meropenem (Merrem)

IV antibiotics are routine in an ER setting because they’re used as a “first-line therapy when patients come in sick and they’re not sure what’s causing the infection,” explains Dr. Akselrod. But as a medical professional immersed in this field, she is well aware of the fine line physicians must walk in terms of both treating the illness at hand, while not introducing additional infection. “Over time we’ve become cognizant of the risks versus the benefits of this kind of broad-standard therapy,” she says. “It can be a tough call whether or not to start IV antibiotics. What helps us make the right decision is a judicious approach and trying to have a specific reason for giving antibiotics.”

Which antibiotics are less likely to cause C.Diff?

If you are at high risk for C.Diff, it’s worth talking to your healthcare provider about choosing a lower-risk treatment. The antibiotics that are less likely to cause C.Diff include:

What antibiotics treat C.Diff?

Although broad-spectrum meds are at the top of the list of C.Diff causes, there are only a few types of C.Diff antibiotics capable of curing this particular infection. Vancomycin is the most frequently used antibiotic for C.Diff, says Dr. Prouty, citing the importance of oral, as opposed to IV, treatment: “The IV doesn’t actually penetrate the gastro-intestinal system, so it’s pretty much useless.” And since all infections are caused by different microbes (a bacterium that causes disease), “not all antibiotics are going to target those microbes and kill them,” she says. Therefore,specific drugs must be used in C.Diff treatment.

It has been suggested that rates of C.diff have fallen in recent years at least partially due to antibiotic stewardship programs in hospitals, which seek to reduce the prescribing of unnecessary antibiotics. But when it comes to patients being proactive over C.Diff prevention, Dr. Akselrod says the number one thing they can do is have a frank conversation with their medical provider about whether or not they “really need that antibiotic, and to minimize the time spent on it.”