Nosocomial C. difficile Common in Pneumonia

ACEP News
July 2010

By Bruce Jancin
Elsevier Global Medical News

0710 C difficile
The C. difficile acquisition rates were 11.2% overall and 7.2% for the toxigenic strains, said Dr. Anke H. Bruns. 

VIENNA - The three major guideline-recommended, empiric antibiotic strategies for community-acquired pneumonia are associated with similar rates of nosocomial acquisition of Clostridium difficile, according to a prospective, observational study.

The nosocomial C. difficile acquisition rates documented in the Dutch study - 11.2% overall and 7.2% for the more worrisome toxigenic strains--are far from inconsequential. In the United States, with an estimated 1 million hospital admissions annually for community-acquired pneumonia (CAP), the toxigenic-strain acquisition rate extrapolates to 72,000 new carriers of toxigenic C. difficile per year, Dr. Anke H. Bruns pointed out at the annual European Congress of Clinical Microbiology and Infectious Diseases.

"This is a large contributor to the spread of C. difficile," observed Dr. Bruns of University Medical Center Utrecht, the Netherlands.

She reported on 107 Dutch patients hospitalized with severe CAP, for which 41% were treated with moxifloxacin, 44% with beta-lactam monotherapy, and the rest with beta-lactam/macrolide combination therapy. Participants were followed for 30 days, with stool samples collected on admission, 5 days later, 3 days after completion of antibiotic therapy, and on day 30.

Infectious Diseases Society of America guidelines recommend either of two antibiotic regimens as first-line treatment for CAP patients who are on general medical wards and are thought not to have Legionella pneumonia: monotherapy with a respiratory fluoroquinolone or combination therapy of beta-lactam and macrolide.

Dutch guidelines recommend monotherapy with either a fluoroquinolone or beta-lactam or therapy combining a beta-lactam with either a macrolide or fluoroquinolone.

Regarding those regimens as equally effective for CAP, Dr. Bruns and her coworkers sought to learn whether the regimens are also equal in associated risks of acquiring C. difficile colonization. That proved to be so.

Another key study finding was that the prevalence of C. difficile carriage at admission was 9.4%, as determined from stool cultures.

"Most of these patients were asymptomatic, and therefore they constitute an important reservoir for the spread of disease, especially because skin contamination was also involved in several cases," Dr. Bruns said.

In a multivariate analysis, the parameters strongly associated with C. difficile carriage were the use of intravenous antibiotics for more than 7 days (associated with a 3.9-fold risk), hospitalization within the previous 3 months (4.1-fold risk), and tube feeding (4.4-fold risk).

The study has several major clinical implications, Dr. Bruns noted. One stems from the finding that no one antimicrobial proved to be associated with increased risk for emergence of C. difficile. That argues against banning any specific agent, such as fluoroquinolones or cephalosporins, for the treatment of CAP, as has been advocated.

Instead, according to Dr. Bruns, it makes more sense to implement strategies aimed at reducing overall antibiotic use in CAP patients, such as shorter treatment courses or an earlier switch from intravenous to oral agents. That approach has great potential, given that treatment of respiratory tract infections accounts for two-thirds of all antibiotic use worldwide, she continued.

The other take away point is that patients hospitalized for treatment of CAP have a roughly 1-in-10 baseline prevalence of C. difficile carriage. Routine screening of CAP patients and institution of appropriate hygiene measures are worth considering, Dr. Bruns said.

Dr. Bruns disclosed having no financial conflicts regarding the CAP study.

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