Summary Background There are few data on the epidemiology and outcomes of influenza infection in recipients of solid-organ transplants. We aimed to establish the outcomes of pandemic influenza A H1N1 and factors leading to severe disease in a cohort of patients who had received transplants. Methods We did a multicentre cohort study of adults and children who had received organ transplants with microbiological confirmation of influenza A infection from April to December, 2009. Centres were identified through the American Society of Transplantation Influenza Collaborative Study Group. Demographics, clinical presentation, treatment, and outcomes were assessed. Severity of disease was measured by admission to hospital and intensive care units (ICUs). The data were analysed with descriptive statistics. Proportions were compared by use of χ2 tests. We used univariate analysis to identify factors leading to pneumonia, admission to hospital, and admission to an ICU. Multivariate analysis was done by use of a stepwise logistic regression model. We analysed deaths with Kaplan-Meier survival analysis. Findings We assessed 237 cases of medically attended influenza A H1N1 reported from 26 transplant centres during the study period. Transplant types included kidney, liver, heart, lung, and others. Both adults (154 patients; median age 47 years) and children (83; 9 years) were assessed. Median time from transplant was 3.6 years. 167 (71%) of 237 patients were admitted to hospital. Data on complications were available for 230 patients; 73 (32%) had pneumonia, 37 (16%) were admitted to ICUs, and ten (4%) died. Antiviral treatment was used in 223 (94%) patients (primarily oseltamivir monotherapy). Seven (8%) patients given antiviral drugs within 48 h of symptom onset were admitted to an ICU compared with 28 (22.4%) given antivirals later (p=0.007). Children who received transplants were less likely to present with pneumonia than adults, but rates of admission to hospital and ICU were similar. Interpretation Influenza A H1N1 caused substantial morbidity in recipients of solid-organ transplants during the 2009–10 pandemic. Starting antiviral therapy early is associated with clinical benefit as measured by need for ICU admission and mechanical ventilation.

NCT00817908.

Resistant bacterial infections are important causes of morbidity and mortality after liver transplantation (LT). This was a retrospective cohort study evaluating the outcomes associated with carbapenem-resistant Klebsiella pneumoniae (CRKP) infections after LT. In a 2005-2006 cohort of 175 consecutive LT recipients, 91 infection episodes were observed in 61 patients (35%). The mortality rate 1 year after LT was 18% (32/175). Enterococcus (43%) and Klebsiella species (37%) were the most frequently isolated bacteria. CRKP infections occurred in 14 patients, and 10 of these patients (71%) died. Seven of these deaths occurred within 30 days of the CRKP infection. The median time to the onset of CRKP infections was 12 days (range ¼ 1-126 days) after LT. The survival rate was significantly lower for patients with a CRKP infection versus patients without a CRKP infection (29% versus 86%, log-rank P < 0.001). In a multivariate analysis, the only pre-LT and post-LT clinical variables significantly associated with death were a Model for End-Stage Liver Disease score 30 (hazard ratio ¼ 3.4, P ¼ 0.04) and a post-LT CRKP infection (hazard ratio ¼ 4.9, P ¼ 0.007). In conclusion, the outcomes associated with CRKP infections in LT recipients are poor. Because the optimal treatment strategies for CRKP infections remain undefined, improved preventive strategies are needed to curtail the devastating impact of CRKP in LT recipients.

Successful preemptive cytomegalovirus (CMV) therapy in transplant patients depends on the availability of sensitive, specific, and timely diagnostic tests for CMV infections. The pp65 antigenemia assay has been used for this purpose with considerable success. Quantification of CMV DNA is currently regarded to be an alternative diagnostic approach. The precise relationship between these two methods has still to be defined, but is essential to compare diagnostic results. This study compared the results of both assays with a large series of transplant recipients in different categories. An internally controlled quantitative real-time CMV DNA PCR was used to test 409 plasma samples from solid organ transplant (SOT) and stem cell transplant (SCT) patients. Levels of CMV DNA in plasma correlated well with classified outcomes of the pp65 antigenemia test. Despite this correlation, the quantitative CMV PCR values in a class of antigen test results were within a wide range, and the definition of an optimal cutoff value for initiating treatment required further analysis by a receiver-operating characteristic curve analysis. This is essential for reactivating infections in particular. For the SCT patients the optimal cutoff value of CMV DNA load defining relevant viral reactivation (in this assay, 10,000 copies/ml) was slightly higher than that for the SOT patients (6,300 copies/ml). Based on a comparison with the established pp65 antigenemia assay, quantification of CMV DNA in plasma appeared to be capable of guiding the clinical management of transplant recipients. This approach may have important advantages, which include a superior reproducibility and sensitivity, allowing the inclusion of kinetic criteria in clinical guidelines.