ATLANTA — Both health care-associated and community-acquired infections caused by the exotoxin-producing bacillus Clostridium difficile continue to increase, Dr. L. Clifford McDonald said during a meeting on emerging clostridial disease sponsored by the Centers for Disease Control and Prevention.
Better surveillance for C. difficile-associated disease (CDAD)—which can range in severity from mild diarrhea to fulminant colitis and death—has become a priority for the CDC.
The meeting, also sponsored by the Food and Drug Administration and the National Institute of Allergy and Infectious Diseases, was convened to develop a research agenda for studying both C. difficile and the related anaerobic bacterium Clostridium sordellii, which has been linked to complications following medical abortions (see related story).
The CDC plans to issue a formal statement saying that all health care facilities should conduct some type of surveillance for CDAD, a recommendation the agency has already made informally through its Web site and public presentations. The CDC is also using established networks, such as the Emerging Infections Programs' FoodNet project, and various pilot studies and state-based epidemiologic investigations to isolate CDAD cases that arise in the community, including human infections that have also appeared in food-producing animals and strains seen in pregnant women, said Dr. McDonald, a medical epidemiologist at the CDC's Division of Healthcare Quality Promotion.
Hospital discharges for which CDAD was listed as any diagnosis doubled between 2000 and 2003 (Emerg. Infect. Dis. 2006;12:409–15). And in the latest yearly update of an ongoing survey, CDAD rates rose by another 25% from 2003 to 2004, from 61 per 100,000 population (178,000 total discharges) to 75 per 100,000 (211,000 discharges). Rates have been highest among adults aged 65 years and older.
Although most CDAD cases are still thought to arise in health care facilities, recent reports of community-associated cases—including some without recent antimicrobial use—have prompted concern that the problem may be underrecognized. At present, C. difficile cases are not nationally reportable.
Last December, the CDC reported a total of 33 cases of community-acquired CDAD in four U.S. states, including 10 infections among pregnant women and 8 in patients who did not have recent antimicrobial use (MMWR 2005;54:1201–5).
More recently, the CDC found that community-associated CDAD is increasing among patients seeking care at the Atlanta Veterans Affairs Medical Center. As of March 2006, about 30% of all CDAD cases there have occurred in outpatients, compared with about 10% in 2003. Of 61 outpatients with CDAD seen at the VA during 2003–2006, 50 had not been hospitalized in the previous 3 months and 19 had not received antimicrobials in the prior 30 days, Dr. McDonald reported.
Use of proton-pump inhibitors (PPIs) appeared to increase the risk; the CDAD patients without antimicrobial exposure were more likely to have been exposed to PPIs than were those with antimicrobial exposure (65% vs. 12%), he said.
Following the report of the 10 CDAD cases among pregnant women, the CDC conducted a survey of 405 infectious disease clinicians. Of those, 17 reported having personally seen such cases and another 23 were aware of such cases in their community. Of the 48 cases reported by the survey respondents, 14 of the infections occurred prior to delivery, 20% of the women developed recurrent disease, and three developed toxic megacolon. There was one fetal loss and one maternal death. It is unknown whether any of these cases were among those previously reported.
The infection is also emerging in food-producing animals, with recent outbreaks among neonatal pigs, dairy calves, and beef. Recently, the CDC has investigated seven cases of human CDAD in seven different states; in these patients, the strains appeared genetically similar on pulsed field gel electrophoresis to the epidemic animal strains, which has not been found in the past.