Bacteremia in solid organ transplant recipients: Incidence, etiology, risk factors and evolution. A multicenter study

Abstract

Background: Solid-organ transplantation (SOT) has become the preferred approach to treat end-stage organ disease. While preventive strategies have reduced the risk for classical opportunistic infections, bacterial -particularly bloodstream infections (BSI)- remain the most frequent short-term complications in SOT recipients and potentially life threatening. Our objective was to analyze the epidemiology, microbiological characteristics and risk factors associated with morbidity and mortality of BSI in SOT during the first 90 days after transplantation. Methods & Materials: Prospective, observational, multicenter study. Through a single data collection record, all BSI in SOT during the first 90 days post-transplantation were enrolled between May 2016 and September 2017. Results: We documented 104 episodes of BSI in: kidney (67%), liver (13%), heart (8%) and other (12%) transplant recipients. Thymoglobulin plus corticoids was the most common induction immunosuppression (43%) in kidney transplant, while tacrolimus, steroids and micofenolic acid was for maintenance (68.5%). 34% of the patients were colonized by multi-drug resistant organisms (MDRO) 12 months prior to BSI, 29% had a previous infection by these MDRO, and 71% received antibiotics 90 days prior to transplantation. Of the 104 BSIs, 92.3% were of nosocomial acquisition and 20 patients (19.2%) had more than one BSI. Secondary bacteremias accounted for 85% of the episodes, being urinary (56.7%) and surgical site infection (12.5%) the most frequent foci. Gram-negative bacilli (GNB) caused 83% of the BSI, with Klebsiella pneumoniae registered as the most common agent (33%). 60% of the specimens were MDRO, being extended spectrum b-lactamase (ESBL) the most frequent mechanisms (59.7%), followed by carbapenemase production (15%). There was no significant difference in clinical symptoms, signs and severity (measured by Pitt and APACHE II scores) between patients infected by MDRO and non-MDRO. An adequate empiric antibiotic therapy was registered in 80% of non-MDRO BSI, and 73% in MDRO BSI (p = 0.67) There was no difference in 30-day overall mortality between both groups (24% vs 21%, p = 0.68) Conclusion: It is essential to know the epidemiology of BSI and the mechanisms of resistance of the MOs in order to improve prophylaxis and empirical therapies, to finally reduce the impact of these infections in mortality.