Web Exclusives

Judicious Antibiotic Use Reduces C Diff Burden

By Jamie Santa Cruz

Antibiotic overuse has lead to an extremely high incidence of C diff infections. Physicians must be vigilant in prescribing antibiotics only in cases where there is a necessity.

New research recently published in the New England Journal of Medicine reveals that the prevalence of C diff infections remains stubbornly high in the United States. The new analysis, based on data from 10 disparate US locations, estimates that there were nearly 500,000 C diff infections across the United States in 2011.1

Significantly, the study, led by scientists at the Centers for Disease Control and Prevention (CDC) in collaboration with researchers at the University of Rochester Medical Center (URMC), also found that the C diff disease burden is not limited to hospital and long term care settings. In fact, 30% to 35% of cases arose in the community. Among the community-associated cases, patients often reported having some contact with outpatient physician offices, an emergency department, a dentist, or some other health care provider prior to developing the infection, and many had received antibiotics. But they had not stayed overnight in a hospital nor had they been in a long term care setting.

"We always used to think of C diff as a disease that happens in people in the hospital," says Ghinwa Dumyati, MD, director of the communicable diseases surveillance and prevention program at URMC's Center for Community Health, and one of the study authors. "This shows that's no longer true. The disease is occurring in the community."

This latest CDC analysis represents the most extensive population-based study of C diff conducted to date in the United States. The overall estimate of the C diff burden it presents is higher than previous estimates, though this may be due in part to the fact that the present study relied on different surveillance methods and more sensitive testing than previous reports. Still, the results underscore the significance of the C diff burden in the United States.

Multiple factors contribute to the prevalence of the infection, according to Belinda Ostrowsky, MD, MPH, director of the Antimicrobial Stewardship Program at Montefiore Medical Center in New York City, who was not involved in the study. Overuse of antibiotics is the key driver; though antibiotics kill harmful bacteria, they also kill beneficial bacteria, making it easier for C diff to take root. But another major factor, Ostrowsky says, is the fact that aggressive treatments such as chemotherapy, aggressive antibiotics, and surgery are increasingly available for significant illnesses. Although aggressive treatments can prolong life, they can also leave patients in a compromised state of health and increase their risk of infections.

Judicious Antibiotic Usage Needed
Given the strong association between C diff and antibiotic use, the most critical step for physicians to take to reduce C diff prevalence is to use antibiotics judiciously. "Of course, if a patient has an infection, we want them to get treated, [but] sometimes a patient doesn't need an antibiotic," Ostrowsky says.

Previous research has demonstrated substantial overuse of antibiotics in inpatient settings. A study from the CDC last year found that more than 50% of all hospitalized patients receive an antibiotic on a given day, most commonly for infections of the lower respiratory tract, urinary tract, and skin and soft tissue.2 Meanwhile, a separate study concluded that at least 30% of antibiotic use in the inpatient setting is likely unnecessary.3 Those patterns of overuse should prompt physicians to question themselves before prescribing, Dumyati says. "Are those treatments for pneumonia, are those treatments for UTIs [urinary tract infections], are those treatments for skin and soft-tissue infections appropriate or not?"

Though overuse is common in hospitals, the problem is prevalent elsewhere as well. In the community setting, Dumyati says, the majority of overuse tends to occur with viral infections, where prescriptions are frequent even though viruses are known to be unresponsive to antibiotics. Another common scenario for overuse, particularly in nursing homes, is overdiagnosis of UTIs. Providers might link patients' confusion or general sense of feeling poorly to a UTI, but these symptoms don't necessarily stem from UTIs, Dumyati says. Physicians should take precautions to ensure that a UTI is actually the source of the problem and antibiotics are necessary before prescribing.

In those cases where antibiotics are actually needed, physicians should choose the spectrum and duration carefully. In many cases, Ostrowsky says, patients receive an antibiotic course that is too broad, killing more bacteria than necessary, or a course that lasts unnecessarily long.

Although antibiotics of all kinds should be used judiciously, one type in particular warrants particular vigilance, Dumyati says. The North American pulsed-field gel electrophoresis type 1 (NAP1) is a common strain of C diff, particularly in hospitals, where it accounts for approximately 30% of cases.1 This strain is resistant to quinolones, making quinolones a particularly high-risk type of antibiotic. (Dumyati also warns against cephalosporins as another high-risk form.) If physicians want to start somewhere, focusing on NAP1 and limiting these particular high-risk antibiotics is useful, she says. At the same time, however, she discourages clinicians from focusing too much on any particular antibiotic because all antibiotics are ultimately risky. "You cannot just stop one type of antibiotic; you have to focus on the amount of antibiotics [in general]."

After patients have been started on antibiotics, those who are in a hospital should be reevaluated over time. When patients are very sick, physicians often have to initiate use of multiple antibiotics, Dumyati says. But within 48 to 72 hours, when cultures are available, patients should be reassessed to determine whether it's possible to remove one of the antibiotics, to change from intravenous to oral, or to switch to an antibiotic of a narrower spectrum.

Other Helpful Steps
Though judicious antibiotic use is the main key to reducing the C diff burden in the United States, Dumyati and Ostrowsky agree that several other steps are also important, including the following:

Early and accurate diagnosis. Most physicians are aware of the C diff problem and are working to protect patients, Ostrowsky says, but in some cases, clinicians simply don't think of C diff as a potential diagnosis for a patient's condition early on. If a patient has diarrhea, physicians should be vigilant about the possibility the infection is present. "Everybody is out there trying their best, but you may not make a diagnosis if you don't think of the condition," she says.

Testing options to confirm C diff infection have changed in recent years, with a national movement toward more sensitive tests. Although not all facilities have access to the newer methods yet, Dumyati encourages physicians to opt for a nucleic acid test when possible over less-sensitive enzyme-linked immunosorbent assay tests.

Infection control procedures in patients' hospital rooms. As soon as patients have been diagnosed, they should be isolated, Ostrowsky says. With confirmed or suspected C diff patients, physicians should wear a gown and gloves and wash their hands regularly to reduce the risk of transmission. Patients should be encouraged to wash their hands regularly, especially before eating.

Environmental cleanliness. According to Dumyati, some data suggest that C diff can be transferred to patients from the environment itself, not only from health care workers. Therefore, patients' rooms should receive a thorough cleaning each day during their stay and upon discharge. Though physicians are not involved in this task directly, Dumyati says, they can help create a safer environment by communicating with nurses and environmental services staff about the importance of cleanliness.

Patient education. Patients sometimes want antibiotics even when they are unnecessary, but physicians should educate them about the harms of antibiotic overuse and communicate about when antibiotics are needed and when they are not, Ostrowsky says. In cases where antibiotics are not necessary, care providers should work with patients to focus on supportive care measures, such as decongestants and fluid intake for cases of flu or other viral conditions.

If and when patients develop C diff in the outpatient setting, Dumyati says they should be advised about how to prevent contamination of the household environment and transmission among family members (eg, if there are two bathrooms in the home, the C diff patient should use only one.)

Though the continued high prevalence of C diff remains a significant problem, Ostrowsky finds encouragement in the fact that the issue is currently receiving substantial attention. Both physicians and patients are increasingly attuned to the risks, and that, she suggests, is a hopeful sign for the future. "Throughout the US this has really been a challenge, but smart people are putting their efforts toward making sure we're protecting our patients in every way."

— Jamie Santa Cruz is a freelance writer based in Englewood, Colorado.

1. Lessa FC, Mu Y, Bamberg WM, et al. Burden of Clostridium difficile infection in the United States. N Engl J Med. 2015;372(9):825-834.

2. Magill SS, Edwards JR, Beldavs ZG, et al. Prevalence of antimicrobial use in US acute care hospitals, May-September 2011. JAMA. 2014;312(14):1438-1446.

3. Hecker MT, Aron DC, Patel NP, Lehmann MK, Donskey CJ. Unnecessary use of antimicrobials in hospitalized patients: current patterns of misuse with an emphasis on the antianaerobic spectrum of activity. Arch Intern Med. 2003;163(8):972-978.