Infections in BMT depend upon: 

(1) the underlying illness of the patient, 

(2) the conditioning regimen,

(3) the graft and matching 

(4) the type of transplant

(5) the presence of graft-versus-host disease (GVHD).

• Profound neutropenia (<500 cells/mm3 ) of greater than 10-day duration is considered a strong risk factor for bacterial and invasive fungal infection