Infectious complications still remain one of the major causes of morbidity although great success has been achieved in transplantation. About 75% of transplant recipients show evidence of microbial invasion just in the first year after transplantation. The risk of infection is largely determined by interaction of the following three factors
-The presence of technical and anatomic abnormalities
-Environmental exposures
-Net state of immunosupression
The major factor responsible for post transplant infections in all transplantation practices is the use of immunosuppression which impairs host defence mechanisms. Etiologic agents of post transplant infections became more predictable in the last two decades since immunosuppressive protocols have been standardized. In other words, a time line that demonstrates the relationship between the occurence of the infection and the duration after transplantation has been developed. Experiences have shown that post transplant period can be categorized into three general time frames in accordance with the occurrence of infections:
-The first month after transplantation; most infections occured in this period are similar to infections in the general surgical patients
-The period from 1 to 6 months after tx; opportunistic infections are common in this period since the net state of immunosupression has settled.
-The period more than 6 months after tx; the main causes of infections are community acquired infections.
Exceptions to this global time line are expected or unexpected environmental exposures. The environmental exposure may occur in hospital or in community. So the the regional differences seen after transplantation are determined by the endemic or epidemic etiological agents of the region. This region can be a hospital, a city, a country or a continent.
When we evaluate our region; the rates and types of infections seen in the first 6 months are similar with the other parts of world. On the other hand, beyond the first 6 months, when patients commonly experience community acquired infections, the rates of some infections such as gastrointestinal parasitic infections, pulmonary and extrapulmonary tuberculosis and the urinary tract infections caused by multidrug resistant bacteriae are determined to be higher.
The time line of posttransplant infections may only be used as a a guideline for patient care. But clinicians should take the epidemiological varieties of the region into consideration.