Multidrug-resistant infection risk climbs with longer hospital stays

The risk of developing an infection during hospitalization due to a multidrug-resistant organism increases by 1% for each day of the hospitalization, according to a report published by Infection Control Today.

During the 54^th Interscience Conference on Antimicrobial Agents and Chemotherapy this week, researchers from the Medical University of South Carolina presented data from their retrospective analysis of 949 patients with Gram-negative infection from 1998 through 2011 from their institution. They wanted to determine the relationship between the development of a multidrug-resistant pathogen in hospitalized patients and length of stay. Multidrug resistance was defined as resistance to one or more drugs from three or more antibiotic classes.

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“In the first few days of hospitalization the percentage of infections associated with Gram-negative bacteria classified as multidrug-resistant was about 20 percent and rose steadily until four or five days then jumped dramatically, peaking at over 35 percent at 10 days,” the report stated. “Statistical analysis suggested an additional 1 percent risk per day of hospitalization.”

The researchers noted a difference among pathogens in terms of multidrug-resistance risk. “When controlling for time to infection and using Klebsiella pneumonia as the reference pathogen, it was found that Enterobacter spp. were 5.57 times more likely to multidrug resistant while Pseudomonas aeruginosa was 0.44 times less likely to be multidrug resistant,” the researchers wrote.

The findings demonstrate the risk of acquiring a multidrug-resistant infection when hospitalized and the need to avoid long hospital stays, when possible.