Study: Antibiotics Use to Blame for C. diff Infections

By John Palmer

A new study has found a correlation between high use of certain antibiotics and the prevalence of a common gastrointestinal illness in hospitals.

The study, published September 16, 2019 in Infection Control & Hospital Epidemiology, the journal of the Society for Healthcare Epidemiology of America (SHEA), found that higher hospitalwide use of four classes of antibiotics thought to increase the risk of the dangerous intestinal illness Clostridium difficile (C. diff) was associated with greater prevalence of hospital-associated C. diff.

The study found that for every 100 days of facilitywide antibiotic therapy using one of the four antibiotics considered high risk, researchers found a 12% increase in hospital-associated C. diff infection (CDI), though when the antibiotics were analyzed separately, only cephalosporins were significantly correlated with hospital-associated C. diff.

“Antibiotic overuse has come under scrutiny as a major driver of CDI, with ∼50% of inpatients prescribed an antibiotic during hospitalization and 30% of these antibiotics being potentially unnecessary,” wrote the study’s authors. “Extensive research has shown the association of patient-level antibiotic use and CDI risk. Moreover, a CDI practice guideline highlights antibiotics at particularly high risk of causing CDI.”

The four high-risk classes were cephalosporins (used for a wide variety of bacterial infections), fluoroquinolones (used for respiratory and urinary tract infections), carbapenems (broad-spectrum antibiotics often reserved for unresponsive infections), and lincosamides (used against staph and strep infections).

C. diff infections, which can cause life-threatening symptoms ranging from diarrhea to inflammation of the colon, affect nearly a half million patients in the United States each year and cause approximately 15,000 deaths per year.

The lack of significant results for C. diff for some classes of antibiotics may reflect reduced use through stewardship, the authors said.

“This highlights the importance of ongoing monitoring of antibiotic use in hospitals for patient safety as it relates to the effect of antibiotics on C. difficile infections. In the future, it will also be important to look at the effect of antibiotic use on both C. difficile infection and antibiotic resistance simultaneously, rather than examining each piece as separate endeavors,” said L. Clifford McDonald, MD, medical epidemiologist at the Centers for Disease Control and Prevention (CDC) and an author of the study.

The infection is not going away. C. diff is a naturally occurring bacterium that lives among the millions of other bacteria in our guts, and for the most part it’s kept in check by the “good” bacteria that keep our digestive systems healthy.

But when patients in the hospital are given antibiotics to fight bacterial infections, the good bacteria are often killed as well, and that’s when C. diff takes over. The resulting infection can cause severe diarrhea and other chronic symptoms until the digestive flora can be brought back to normal. In elderly patients and those with compromised immune systems, the results can be deadly.

Hospitals have been fighting a battle with the bug for years, and C. diff colonization has become a somewhat common—though obviously not acceptable—aftereffect of increased antibiotic use.

What’s worse is that C. diff is being found, and perhaps transmitted, in healthcare facilities previously thought safe from it. Medical clinics were once considered generally safe from C. diff because of their quick patient turnover, and because sicker and longer-term patients are seen at hospitals. But a 2015 CDC study published in the New England Journal of Medicine found that the prevalence of the infection was much higher than once thought, affecting up to 500,000 people annually. In addition, the study revealed that about 29,000 deaths were associated with the infection in hospitals, about double the CDC’s previous estimate. The study did not cite antibiotic usage as a possible link to the increased number of illnesses. It found that up to 150,000 people who had not previously been in the hospital came down with C. diff in 2011. Of those, about 80% had visited a doctor’s or dentist’s office in the 12 weeks before the diagnosis.

The authors wrote that recent guidelines identified the four classes of antibiotics examined in this study as high risk, though results of previous research evaluating facility-level use of these antibiotics and rates of C. diff have been inconsistent. Researchers in the study analyzed microbiological and pharmacy data from 171 hospitals included in a database from Becton, Dickinson and Co., in Franklin Lakes, New Jersey, to look at the impact of hospitalwide use of these four classes of antibiotics on hospital-acquired C. diff.

“This is possible in our era of electronic medical records because antibiotic usage data has become more available,” the researchers stated. “A facility can use the National Healthcare Safety Network Antibiotic Use and Resistance Module and interpret results using the standardized antibiotic administration ratio (SAAR) to have a better understanding of how antibiotics are being used and identify areas for improvement.”

Higher C. difficile infection rates were also associated with a larger portion of patients over age 65, higher rates of community-onset C. difficile, longer length of stay, and teaching hospitals.

The study’s release came less than two weeks before the Centers for Medicare and Medicaid Services (CMS) released revised Conditions of Participation for hospitals and critical access hospitals that require the development and implementation of antimicrobial stewardship programs (ASP) to help reduce inappropriate antibiotic use and antimicrobial resistance.

The rule, first proposed by CMS in 2016, finalized requirements for nursing facilities to have a stewardship program in response to widespread misuse of antibiotics in such settings, a practice that leads to the spread of so-called “superbugs.”

The CDC estimates that of the 4 million patients receiving care in nursing homes, 70% of them received antibiotics in 2017, with up to 75% of those drugs prescribed incorrectly.

The Joint Commission followed suit in 2017, issuing its own standards that require acute care hospitals, critical access hospitals, and nursing homes to have an antibiotic stewardship program to maintain their accreditation. The commission expanded its requirements in June 2019 to include ambulatory care centers, effective as of January 1 this year.

Where hospitals have failed in their efforts to curb antibiotic use, some have found success in alternatives, such as technological improvements to housekeeping practices.

For example, it’s been known for centuries that minerals such as copper and silver have antimicrobial properties that repel infections; now, some healthcare facilities nationwide are embedding these materials into high-touch surfaces in hospital rooms such as countertops, over-the-bed tables, bed rails, and textiles ranging from bed linens to patient gowns.

Others have experimented with so-called “germ-zapping robots” that automatically scan the surfaces in a room and bathe the room in ultraviolet light—neutralizing deadly germs and preventing them from multiplying. At a cost of around $100,000, and boasting a disinfection rate of close to 90%, these robots are a cost worth incurring, many hospitals say, especially when the tool is added to existing housekeeping efforts.

John Palmer is a freelance writer who has covered healthcare safety for numerous publications. Palmer can be reached at