WASHINGTON — Mechanical ventilation significantly increases the risk that a hospitalized patient will develop Clostridium difficile-associated diarrhea, Dr. Chad A. Spangler and Dr. George F. Risi reported in a poster at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.
This novel finding “has the potential to support new, additional prevention and control strategies in high-risk patient populations,” said Dr. Spangler and Dr. Risi, of St. Patrick Hospital, Missoula, Mont.
The incidence of C. difficile-associated diarrhea (CDAD) rose from 1.6 to 8.0 cases per 1,000 discharges between 2001 and 2004 at the investigators' 200-bed hospital, with most cases occurring in the intensive care unit. There was no change in the rate of CDAD cases between 2003 and 2004 despite a reduction in the use of both antipseudomonal penicillins and fluoroquinolones during that period.
Among 3,247 patients who received antibiotics and had a length of stay greater than 3 days between January 2004 and March 2005, a total of 19% required ventilation. Of those 614, CDAD developed in 47 (7.6%). With the ventilated population excluded, the infection rate was just 1.2%. The odds ratio for infection was 6.6 among those who were ventilated, compared with those who were not, the investigators reported at the meeting, which was sponsored by the American Society for Microbiology.
Other significant risk factors for CDAD included ICU stay (odds ratio 5.9); use of either proton pump inhibitor or H2 blocker antacids (2.7); and exposure to carbapenems (4.9), third-generation cephalosporins (4.0), or antipseudomonal penicillins (4.5). Patients requiring more than 2 days on the mechanical ventilator were 11 times more likely to develop CDAD than were those requiring less ventilation, they reported.