Special Report

Transplant infections: A matter of timing

The majority of clinically important infections associated with solid-organ allograft transplantations occur within the first 180 days following the procedure, with nosocomial infections likely to strike within the first month, says Marian Michaels, MD, MPH, transplant infectious disease physician at the Childrens Hospital of Pittsburgh. Recent published work on the trend by Michaels and co-author Michael Green, MD, is summarized as follows:1

Early period (0 to 30 days after transplantation)

— Infections in this period tend to be associated with pre-existing conditions, and in general, they are caused by either bacteria or fungi.

— Surgical manipulation also predisposes patients to early bacterial infections.

— Herpes simplex virus reactivation can occur during this early period.

Intermediate period (30 to 180 days)

— This period is the typical time of onset of infections associated with donor transmission (either organ or blood product), reactivated viruses, and opportunistic infections.

— Cytomegalovirus peaks in incidence of infection.

— Epstein-Barr virus (EBV), post-transplant lymphoproliferative disorders (PTLDs), Pneumocystis carinii pneumonia, and toxoplasmosis become evident in many patients.

Late period (greater than 180 days)

— Late infectious complications after transplantation are less well-characterized because patients have usually been discharged from the transplant center to their respective homes, making accurate accumulation of data difficult.

— Chronic or recurrent infections can occur after each type of solid-organ transplantation. In general, patients with these types of infections are identified as having an uncorrected technical difficulty (e.g., vesicoureteral reflux, biliary stricture).

— EBV-associated PTLD continues to occur in the late period.

Infections throughout the postoperative course

— Iatrogenic factors are an important cause of bacterial and fungal infections at all times after transplant, but predominate in the early transplant period.

— The risk of infection persists for the entire period that central venous catheters remain in place.

— Urethral catheters and nasotracheal or endotracheal tubes also increase the risk of infection.

— Nosocomial acquisition of community viruses such as RSV, rotavirus, influenza, and parainfluenza is a seasonal risk. The severity of disease associated with these pathogens tends to decline with increasing time from transplant.

Reference

1. Green MD, Michaels MG. "Solid-Organ Transplan tation: Infection and Prevention." In: Gower J, ed. APIC Curriculum for Infection Control Practice. St. Louis: Mosby; 1996, pp. 51-1 to 51-8.