Antibiotics Prescribed by Dentists May Be Contributing to CDI Incidence

Out of all of the healthcare-associated infections that plague health officials, healthcare facilities, and patients alike, Clostridium difficile (C. difficile) is the most common, accounting for upwards of 453,000 cases and a staggering excess financial burden of $1 million on an annual basis.

The threat of C. difficile has investigators all over the world on a mission to learn more about the troublesome infection in order to get a better handle on prevention and control efforts. At ID Week 2017, held in San Diego, California, Maria Bye, MPH, an epidemiologist at the Minnesota Department of Health, provided troublesome insight gleaned from an active population- and laboratory-based Clostridium difficile infection (CDI) surveillance survey: dentists are contributing to the incidence of CDI.

In her presentation, Dr. Bye stressed that antibiotic exposure is a major risk factor for CDI, and unfortunately, dentists have been relatively left out of the conversation when it comes to the development of antibiotic stewardship programs. They shouldn’t be, she argued, as recent data has found that dentists prescribed about 10% of antibiotics in the outpatient setting in the United States in 2013 alone—that amounts to upwards of 24 million prescriptions!

“In dentistry, antibiotics are indicated to treat oral infections, such as tooth abscesses,” Dr. Bye explained. “Historically, recommendations for antibiotic prophylaxis have been created for 2 specific groups of patients: those with heart conditions that may predispose them to infective endocarditis and those with prosthetic joints who may be at risk for developing an infection at the site of the prosthetic.”

However, guidelines for prophylaxis before invasive dental procedures for patients with congenital heart disease and prophylaxis guidelines for patients with prosthetic joints have evolved over the years. The American Dental Association recommends prophylaxis only for patients with specific heart conditions, rather than all congenital heart conditions, and prophylaxis is no longer recommended for patients with prosthetic joints. However, some clinicians continue to prescribe prophylaxis regardless of the recommendations.

Minnesota dentists included in a 2015 survey reported prescribing antibiotics for clinical reasons consisting of the following: 84% prescribed prophylaxis for patients suffering from high-risk conditions, 70% prescribed to battle localized swelling, and 38% prescribed antibiotics for patients experiencing gum pain. They also prescribed for nonclinical reasons, due to precautionary (38%) or legal concerns (24%). Furthermore, less than half of the surveyed dentists were concerned about patients experiencing adverse events, antibiotic resistance, or C. difficile.

In their survey, investigators compared the characteristics of those with community-associated CDI (CA-CDI) who took antibiotics for a dental procedure, with CA-CDI cases who took antibiotics for nondental reasons. “The analyses were conducted with chi-square tests using SAS 9.4,” Dr. Bye added.

The investigators identified a total of 2,176 CA-CDI cases between 2009 and 2015; 75% of these cases were confirmed via interview, and more than half, or 57%, of cases reported taking prescribed antibiotics in the 12 weeks prior to diagnosis on interview. Although upper respiratory infections were the most common indication of antibiotics in these CA-CDI cases, dental procedures came in second, with urinary tract infections close behind.

Of the 926 CA-CDI cases who reported taking prescribed antibiotics in the 12 weeks before receiving a diagnosis, 136, or 15%, received antibiotics for a dental procedure. Furthermore, perhaps even more troubling is that 34% of cases reported having been prescribed antibiotics that were not noted in their medical records, suggesting that physicians may not have been aware that they of these prescriptions made by the patients’ dentists.

Some interesting findings yielded from the survey include:

• Those who received antibiotics for dental procedures were significantly older than those receiving them for other reasons
• 48% of those who received antibiotics for a dental procedure were prescribed clindamycin, which is commonly associated with CDI and only 30% had it listed in their medical records
• Collectively—between drugs prescribed and reported in interview and those noted in medical records—50% of cases reported taking clindamycin compared with 10% of those who took nondental antibiotics

Beginning in July 2015, the investigators started collecting dental antibiotic indications in addition to prescriber information. So far, 76 cases of dental antibiotic use have been identified with top indications including tooth infections/abscesses (43%), oral surgery prophylaxis (35%), and dental cleaning prophylaxis (13%).

“Sixty-seven percent of the 76 cases were prescribed antibiotics by dentists,” Dr. Bye drove home.

Following this research, investigators began collecting data related to patients with heart conditions or who have received joint replacements. Of the cases prescribed dental-related antibiotics, 4 had heart conditions (1 had a valve replacement) and 4 had joint replacements. “Of these 8 cases, only the valve replacement potentially warranted antibiotic prophylaxis under current guidelines,” Dr. Bye explained.

The study had 2 notable limitations: the dental records were not reviewed, and the investigators cannot “attribute CDI to dental prescribing when other antibiotics are prescribed for different indications.”

“In conclusion, our analysis suggests that antibiotics prescribed by dentists are contributing to CDI,” Dr. Bye stressed. Although overall antibiotic prescribing has decreased, dental prescribing is actually increasing. She added, “A recent review indicates that taking any antibiotic can increase a person’s chances of getting CDI by 7 times. When taking clindamycin, you increase the chances by 20 times.”

She closed out her presentation by providing conference attendees with the following recommendations:

• Dentists need to be included in stewardship programs
• Dentists need to consider risk for CDI when prescribing antibiotics
• Clarification and consistency is needed across professional associations when it comes to dental prophylaxis for joint replacement
• More research is needed to better understand risk of adverse events linked with dental procedures

“Everybody plays a role in antibiotic stewardship,” Dr. Bye stressed. “Dentists should follow ADA guidelines for antibiotic prophylaxis and treatment, as well as counsel patients about the risk and symptoms of C. diff and other complications of antibiotic use.”