APIC finds rampant C. diff, new strain suspected
Estimated daily death toll: 301
William Jarvis , MD
An unlucky 13 out of every 1,000 inpatients in recently surveyed hospitals were either infected or colonized with Clostridium difficile, a rate that is 6.5 to 20 times higher than previous incidence estimates.
"In fact, we are being very conservative with that [estimate]," said lead investigator William Jarvis, MD, an infection prevention consultant who conducted the study for the Association for Professionals in Infection Control and Epidemiology (APIC).
Moreover, 94.4% of the patients were symptomatically infected rather than colonized, and many had the type of severe disease that has been associated with the emergence of a hypervirulent new epidemic strain called North American Pulse-field Type 1 (NAP1). However, it is difficult to say whether the NAP1 strain is driving the trend, because the vast majority of hospitals surveyed are not looking for particular strains. In addition, only 1.9% of C. diff-infected patients were identified by culture and only 4.2% of health care facilities routinely perform cultures for C. diff, the survey found.
The Centers for Disease Control and Prevention has previously identified the NAP1 strain — which often is associated with outbreaks due to its increased virulence — in approximately 26 states, Jarvis said at a recent press conference in Orlando announcing the results.
"It really requires a specific clinician to be concerned [enough] to obtain a specimen and send it to the very limited labs that have the capability to identify the strain," he told Hospital Infection Control & Prevention. "One of the questions is: is the impact of C. diff-associated disease [increasing]? We cannot address that directly because we are only doing a one-point-in-time [prevalence survey], but we asked if patients had different severities of illness. Twenty-six percent required ICU admission, 18.2% had shock, and 16.5% required vasopressors. So, we certainly have data to suggest that C. diff infection is severe. The question is, is that due to NAP1 or not? And we can't answer that because no one in our study was looking for it."
The survey of infection preventionists collected data from 12.5% of all medical facilities in the United States that care for virtually every type of patient, including those at acute care, cancer, cardiac, children's, long-term care and rehabilitation hospitals. Responses were received from facilities in 47 states.
IPs were asked to determine on one day during the period of May-August 2008, all C. diff inpatients in their facilities. A total of 1,443 patients were identified with C. diff from among the 648 participating hospitals. Overall, 41% of respondents said their rates of C. diff had increased, while an identical percentage said they remained stable.
"We believe these study results should be a wake-up call for health care providers everywhere," Kathy Warye, CEO of APIC said at the press conference. "Those of us [here] today are concerned that C. diff is not getting the attention it deserves. A year after [a similar APIC MRSA survey,] results were released, we polled our members and discovered that MRSA interventions had gone up 76%. So studies like this can be very powerful."
C. diff gastrointestinal infections typically range in severity from asymptomatic colonization to severe diarrhea, pseudomembranous colitis, toxic megacolon, intestinal perforation, and death. According to the survey, on any one day, the number of patients who die with C. diff infections ranges from 165 to 438 — with an average of 301.The survey estimated that at least 7,178 inpatients on any given day in American health care institutions have C. diff, resulting in an associated cost of $17.6 million to $51.5 million. (See study results.)
In addition to the emergence of the NAP1 strain, other factors contributing to the rise of C. diff include an aging U.S. population, the widespread use of broad-spectrum antimicrobials, and inadequate infection control measures. According to APIC, the latter include delayed diagnosis, delayed isolation precautions, poor hand hygiene and inadequate environmental cleaning. Indeed, the pathogen raises difficult questions for antibiotic use, infection control and environmental eradication, which often requires some kind of bleach solution.
Transmission occurs primarily in health care facilities, where exposure to antimicrobial drugs sets up the gut for onset of disease, triggering diarrhea that leads to a contaminated patient environment by the spore-forming anaerobic bacillus. Prior administration of fluoroquinolones in particular seems to trigger the appearance of cases, but the survey found that some sort of antibiotic stewardship program was in place in only about half the responding facilities. Even where such oversight is reported, it is unclear what precisely is being done to prevent the misuse of drugs. " Antibiotic stewardship sounds real good, but what does that mean and what does it actually accomplish," Jarvis said. "We are lacking studies that show what works best for controlling antibiotic use; and the more I go around the country, the more I realized it really requires an infectious diseases specialist dedicated to that issue."
Even the basic issue of hand hygiene is complicated when it comes to C. diff, which is difficult to remove by the alcohol hand rubs now ubiquitous in hospitals. Thus, the recommendation in caring for C. diff patients is to resort to good old soap and water, but the mixed message is certainly not helpful. "We know that alcohol will not kill the spores," Jarvis said. "Not that soap and water kills the spores, but rather that it rinses it off of your hands." Indeed, some have questioned whether the rise of C. diff is a direct result of the CDC's switch to a heavy emphasis on alcohol-based hand hygiene rubs earlier in this decade. Jarvis expressed doubt that the cause and effect is that direct, but conceded it is "a theoretical issue. Certainly, when we know we have a C. diff patient or when we are doing environmental cleaning of such a patient's room, then it behooves us to use [soap and water] for hand washing and bleach [for room cleaning]," he said.
With many of the reported cases occurring shortly after admission, hospitals need to look for patients with severe diarrhea and be prepared to place C. diff patients under contact isolation. However, most of the infections were not considered truly community-acquired, with some linked to previous health care treatment. Though there have been increasing reports of C. diff in the community, the problem is still primarily transmission within hospitals. "Fifty-four percent were diagnosed at less than 48 hours after admission, which would make you think that those are community-acquired infections," Jarvis reported. "However, when we gave them the CDC criteria for differentiation of community vs. health care-associated, 73% of the patients identified had health care-associated infections."
To reduce the risk of transmission, APIC has published a "Guide to the Elimination of Clostridium difficile in Healthcare Settings." APIC recommendations include:
- a risk assessment to identify high-risk areas for C. diff within the institution, a surveillance program to outline activities, and procedures to provide early identification of C. diff cases;
- adherence to CDC hand hygiene guidelines;
- use of contact precautions (e.g., gloves, gowns, and separating C. diff patients from other patients);
- environmental and equipment cleaning and decontamination, especially items that are close to patients such as bedrails and bedside equipment;
- antimicrobial stewardship programs with focus on restriction of antibiotics associated with C. diff and unnecessary antimicrobial use.
(Editor's note: For more information about the APIC study and guidelines, go to www.apic.org.)