WASHINGTON, D.C.—The incidence of bloodstream infections (BSIs) in solid-organ transplant (SOT) patients is increasing, and pathogens commonly implicated in these infections show high rates of antimicrobial resistance, data suggest. These resistance rates may vary according to the type of organ transplanted.

Clinicians need to be aware of these trends to optimize empiric therapy, according to researchers, who noted that BSIs may increase 100-day mortality in SOT recipients.

“It is important to know whether or not the [BSI] incidence rates are increasing or decreasing over time, as well as what the resistance rates are for these organisms,” said study investigator Erik Dubberke, MD, assistant professor of internal medicine at Washington University School of Medicine in St. Louis, Mo. “This provides important clinical information for choosing empiric therapy and determining when patients may need broader-spectrum antibiotics or whether a change in prophylactic regimens is needed.”

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Few studies have evaluated recent trends in epidemiology and antibiotic resistance in SOT recipients. In a retrospective study, Dr. Dubberke and his colleagues identified 1,474 SOT recipients at their institution between 2003 and 2007. Of these, 78 experienced 100 BSIs.

The overall incidence of BSIs was 6.7% in 2007, up from 3.1% in 2003. The 100-day all-cause mortality was 23.1% for patients with BSIs compared with 3.4% of patients without BSIs. The median time to BSI onset was 17 days (range 1-95 days). The researchers presented findings here at a joint meeting of the Interscience Conference on Antimicrobial Agents and Chemotherapy and the Infectious Diseases Society of America.

The researchers also observed that BSI incidence varied by type of transplanted organ. It was 3.6% among kidney recipients (25 out of 689 patients), 10.8% among liver transplant recipients (39 out of 362 patients), 1.1% for lung transplant recipients (2 out of 271 patients), and 8.5% for heart transplant recipients (11 out of 129 patients).

Overall, the incidence of vancomycin-resistant enterococci, methicillin-resistant Staphylococcus aureus, and ciprofloxacin-resistant Pseudomonas aeruginosa was 57.5%, 50%, and 55%, respectively. In addition, 57.9% of Enterobacteriaceae isolates were resistant to trimethoprim/sulfamethoxazole.

Dr. Dubberke called for greater systematic surveillance of SOT patients and BSIs at medical centers nationwide.