<p>Disseminated toxoplasmosis is an uncommon but highly lethal cause of hyperferritinemic sepsis after hematopoietic cell transplantation (HCT). We report two cases of disseminated toxoplasmosis from two centers in critically ill adolescents after HCT: a 19-year-old who developed fever and altered mental status on day +19 after HCT and a 20-year-old who developed fever and diarrhea on day +52 after HCT. Both patients developed hyperferritinemia with multiple organ dysfunction syndrome and profound immune dysregulation, which progressed to death despite maximal medical therapies. Because disseminated toxoplasmosis is both treatable and challenging to diagnose, it is imperative that intensivists maintain a high index of suspicion for infection when managing immunocompromised children, particularly in those with known positive serologies.</p>
<p>Variation in the gastrointestinal microbiota after hematopoietic cell transplantation has been associated with acute graft-versus-host disease (aGVHD). Because antibiotics induce dysbiosis, we examined the association of broad-spectrum antibiotics with subsequent aGVHD-risk in pediatric patients transplanted for acute leukemia. We performed a retrospective analysis in a dataset merged from two sources: (1) Center for International Blood and Marrow Transplant Research, an observational transplant registry, and (2) Pediatric Health Information Services, an administrative database from freestanding children's hospitals. We captured exposure to three classes of antibiotics used for empiric treatment of febrile neutropenia: (1) broad-spectrum cephalosporins, (2) anti-pseudomonal penicillins and (3) carbapenems. The primary outcome was grade 2-4 aGVHD; secondary outcomes were grade 3-4 aGVHD and lower gastrointestinal (GI) GVHD. The adjusted logistic regression model (full cohort) and time-to-event analysis (sub-cohort) included transplant characteristics, GVHD-risk factors, and adjunctive antibiotic exposures as covariates. The full cohort included 2,550 patients at 36 centers; the sub-cohort included 1,174 patients. In adjusted models, carbapenems were associated with an increased risk of grade 2-4 aGVHD in the full cohort (aOR 1.24, 95%CI 1.02-1.51) and sub-cohort (subHR 1.31, 95%CI 0.99-1.72), as well as with an increased risk of grade 3-4 aGVHD (subHR 1.77, 95%CI 1.25-2.52). Early carbapenem exposure (prior to day 0) especially impacted aGVHD-risk. For antipseudomonal penicillins the associations with aGVHD were in the direction of increased risk but were not statistically significant. There was no identified association between broad-spectrum cephalosporins and aGVHD. Carbapenems, more than other broad spectrum antibiotics, should be used judiciously in pediatric transplant patients to minimize aGVHD-risk. Further research is needed to clarify the mechanism underlying this association.</p>