Bloodstream infection after kidney transplantation: epidemiology, microbiology, associated risk factors, and outcome.

Background: Bloodstream infection (BSI) is associated with both relevant morbidity and mortality rates after kidney transplantation.

Methods: From January 1, 2000 to January 31, 2006, all episodes of BSI were retrospectively assessed through the review of medical records in two tertiary teaching Hospitals in Sao Paulo, Brazil, where 3308 transplant procedures were performed during this period. Contaminants and polymicrobial infections were excluded. The main objectives of the study were to describe clinical and microbiologic aspects of BSI, as well as risk factors for both BSI and mortality from these infections in kidney transplant patients.

Results: BSI was detected in 185 patients, with onset after a median of 235 days after transplantation; 62% occurred after 6 months. The primary source of infection was the urinary tract in 37.8%. The most prevalent pathogen overall was Escherichia coli (30.3%). Risk factors for early acquired BSI (first 6 months after transplantation) were acute rejection, ureteric stent placement, and receiving an organ from a deceased donor. For late BSI (after 6 months), associated risk factors were acute rejection, Charlson Comorbidity Score more than or equal to 3, and receiving an organ from a deceased donor. Risk factors related to 30-day mortality were Acute Physiology and Chronic Health Evaluation II Score more than or equal to 20, shock, and respiratory failure.

Conclusions: BSI is most frequently a consequence of urinary tract infection, with a high prevalence of gram-negative bacilli. Severity of disease was the main determinant of 30-day mortality after BSI, and based on the knowledge of risk factors, some interventions are suggested for reducing the rate of BSI after transplantation.