Bacteremia, C. difficile common in recent HCT recipients

Infection remains a significant source of morbidity and mortality among patients who have received hematopoietic stem cell transplantation, with bacteremia and Clostridium difficile infection occurring frequently, study data showed.

“More than 8,000 allogeneic hematopoietic cell transplants are performed annually in North America,” Mindy G. Schuster, MD, MSCE, professor of medicine at the Hospital of the University of Pennsylvania, and colleagues wrote. “Prospectively collected data from multiple, geographically diverse centers are vital to the understanding of infectious complications and to the development of prophylactic and treatment strategies. No multicenter studies have prospectively evaluated the epidemiology, risk factors and outcomes of all infectious complications following hematopoietic stem cell transplantation (HCT).”

Schuster and colleagues performed a prospective, multicenter study of 444 patients who underwent HCT from 2006 to 2011 at four transplant centers in the United States. Median age was 53 years, while median follow-up was 413 days. Most patients (87%) had received HCT for hematologic malignancies.

The overall crude mortality rate was 52%, the researchers reported. Infection caused 21% of deaths, whereas underlying disease caused 44%. More than half of patients experienced bacteremia (52%; n = 231), which tended to occur early after transplant (median day 48). Although gram-negative bloodstream infections occurred less frequently than gram-positive infections, Schuster and colleagues wrote that they produced a higher mortality rate (45% vs. 13%; P = .02). One third of patients (33%; n = 148) developed C. difficile infection, at a median of 27 days after HCT. Forty-eight patients developed a total of 53 invasive fungal infections, with a median time to infection of 142 days, the researchers wrote. Slightly less than half (n = 187; 42%) had viral infections.

Of those patients with cytomegalovirus infection (n = 155), 4% had organ involvement. Another 13 patients (4%) developed varicella zoster infection, which was disseminated in two patients, Schuster and colleagues reported. Researchers identified respiratory viral infections in 49 patients; Pneumocytis jirovecii pneumonia was rare, occurring in just 1% of patients. The researchers reported no documented cases of nocardiosis, toxoplasmosis, endemic mycoses or mycobacterial infection.

“Risk factors for bacteremia and C. difficile infections that occur before engraftment should be examined to help inform prophylactic strategies during different stages of immune reconstitution post-HCT,” the researchers wrote. “Further information on the timing and type of environmental exposures that lead to invasive mold infection is needed in order to prevent these devastating infections. A more individualized and granular understanding of the state of immunosuppression in an individual patient will allow a finer stratification of risk for infection.” – by Andy Polhamus

Disclosure: The researchers report no relevant financial disclosures.