Infections in transplant recipient

The risk of infection after transplant depends on:

We are exposed to many different microbes in the environment in our life time. Such exposure are often benign; patients may remain asymptomatic or develop only mild symptoms. These exposures may result in dormant infections which re-emerge and cause problems in the transplant recipient when they are on immunosuppressive medications. Some examples  of this include infections like tuberculosis and fungal infections. Infections can also come from the donor. 

After transplant, transplant recipients may fall sick after being exposed to sick persons, animals or microbes in the environment. 

During transplant, the recipient undergoes a number of medical procedures. Infections may arise from complications associated with medical instrumentation / medications received (e.g. chemotherapy for bone marrow transplantation). Prolonged periods of bedrest and immobility in the early post transplant period may also result in increased risk of hospital acquired infections such as chest and urinary tract infections. 

The dose of immunosuppresive medications is often the highest in the early post transplant period or during organ rejection. This is also the period when the risk of infections is the highest. With time, as immunosuppression is tapered, the risk of infection is also reduced.