Web Zap*Germs Archive

December 02, 2005

Deadly "C-diff" Infection Spreading to Healthy People

Update 01 Feb 2006: MSNBC Health addresses the C-diff situation, and mentions a controversial idea regarding the spread of this bacteria:
...public health advocates have been perplexed by cases popping up elsewhere in people younger people who had not taken antibiotics.

A study released in December by McGill University researchers suggested that popular heartburn drugs -- proton pump inhibitors such as Prilosec, Prevacid and Nexium -- could reduce stomach acids that curb C-diff production. [see Zap*Germs post on possible benefits of probiotics for this.]

But Dr. L. Clifford McDonald, a medical epidemiologist for the CDC, said other studies have suggested changes in stomach acids are not a factor in C-diff growth.
The CDC and New England Journal of Medicine (NEJM) [article PDF editorial PDF] have reported in the last few days about the rise of a particularly nasty strain of Clostridium difficile (aka "C-diff") that is resistant to commonly used antibiotics. Indeed, this superbug actually thrives in patients who have taken clindamycin and certain fluoroquinolone-type antibiotics (more below). What's unusual is that this strain of the bacteria has been killing people in daily-life, as well as hospital/nursing-home, settings.

We reported earlier this year on C-diff outbreaks in the UK and Canada; the new reports describe outbreaks in the USA. ABC News is running a good AP summary on the CDC and NEJM articles.

About three percent of healthy people are "colonized" with C-diff bacteria, and 20%-40% of hospitalized people, says the NEJM editorial linked above. C-diff live in the colon, usually as inactive spores, but can cause diarrhea and colitis. The bugs spread by spores in feces (poop!); the spores are difficult to kill with most household cleaners. Even washing hands with antibacterial soap doesn't necessarily kill the spores.

C-diff has grown resistant to certain antibiotics that work against other colon bacteria. The result: When patients take those antibiotics, particularly clindamycin and now some fluoroquinolones, other gut bacteria are killed, leaving C-diff to run rampant. Recent cases in four US states show it's causing infections more often in healthy people who have not been treated in healthcare facilities or even taken antibiotics.

The researchers reporting in NEJM found that a virulent strain of C-diff, rarely seen before 2000, accounted for more than half of the samples they studied. That strain has acquired resistance to gatifloxacin and moxifloxacin, which are two of the newest fluoroquinolone antibiotics used in hospitals. It's not known what has made the bacteria more virulent right now.

What to do? The AP account recommends that anyone suffering from severe diarrhea -- not just people in hospitals or nursing homes -- see a doctor. It could be the killer strain of C-diff, and should not be ignored.

The NEJM editorial has the following recommendations for hospital staff:
...monitor for an increasing incidence C. difficile-associated disease on the basis of some classic features: the administration of antibiotics complicated by diarrhea, fever, leukocytosis, sometimes with a leukemoid reaction, and hypoalbuminemia or toxic megacolon, or both. Standard stool assays available in most laboratories will not identify this epidemic strain, but the strain might be suspected on the basis of the number and severity of cases.

Treatment consists of the prompt discontinuation of the implicated antimicrobial agent and the administration of oral metronidazole; for severely ill patients and those who do not have a prompt response to metronidazole, oral vancomycin should be considered.

Prevention efforts should include fastidious use of barrier precautions, isolation of the patient, careful cleaning of the environment with sporicidal agents active against C. difficile, and fastidious use of hand hygiene. This last requirement should include washing hands with soap and water as a supplement to the use of alcohol-based sanitizers, since such sanitizers do not eradicate C. difficile.

Particularly important is antibiotic stewardship with restraint in the use of epidemiologically implicated antimicrobial agents, usually second- and third-generation cephalosporins, clindamycin, or fluoroquinolones, or a combination of the three.


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