Diagnostic performance of a multiplexed gastrointestinal PCR panel for identifying diarrheal pathogens in children undergoing hematopoietic stem cell transplant.

BACKGROUND: Diarrhea is a common complication of hematopoietic stem cell transplantation (HSCT) and is associated with substantial morbidity, but its etiology is often unknown. Etiologies of diarrhea in this population include infectious causes, chemotherapy- or medication-induced mucosal injury and graft-versus-host disease (GVHD). Distinguishing these potential causes of diarrhea is challenging since diarrheal symptoms are often multifactorial, and the etiologies often overlap in transplant patients. The objectives of this study were to evaluate whether the FilmArray gastrointestinal (GI) panel would increase diagnostic yield and the degree to which pre-transplantation colonization predicts post-transplantation infection. METHODS: From November 2019 to February 2021, a total of 158 patients undergoing HSCT were prospectively included in the study. Stool specimens were obtained from all HSCT recipients prior to conditioning therapy, 28 ± 7 days after transplantation and at any new episode of diarrhea. All stool samples were tested by the FilmArray GI panel and other clinical microbiological assays. RESULTS: The primary cause of post-transplantation diarrhea was infection (57/84, 67.86%), followed by medication (38/84, 45.24%) and GVHD (21/84, 25.00%). Ninety-five of 158 patients were colonized with at least one gastrointestinal pathogen before conditioning therapy, and the incidence of infectious diarrhea was significantly higher in colonized patients (47/95, 49.47%) than in non-colonized patients (10/63, 15.87%) (P < 0.001). Fourteen of 19 (73.68%) patients who were initially colonized with norovirus pre-transplantation developed a post-transplantation norovirus infection. Twenty-four of 62 (38.71%) patients colonized with Clostridium difficile developed a diarrheal infection. In addition, FilmArray GI panel testing improved the diagnostic yield by almost twofold in our study (55/92, 59.78% vs. 30/92, 32.61%). CONCLUSIONS: Our data show that more than half of pediatric patients who were admitted for HSCT were colonized with various gastrointestinal pathogens, and more than one-third of these pathogens were associated with post-transplantation diarrhea. In addition, the FilmArray GI panel can increase the detection rate of diarrheal pathogens in pediatric HSCT patients, but the panel needs to be optimized for pathogen species, and further studies assessing its clinical impact and cost-effectiveness in this specific patient population are also needed.

Changes in body composition in children with acute graft-versus-host disease within the first 100 days after hematopoietic stem cell transplantation.

BACKGROUND: Acute graft-versus-host-disease (aGVHD) is one of the main complications of hematopoietic stem cell transplantation (HSCT). This study investigated the changes in body composition of pediatric patients with aGVHD during the first 100 days after HSCT. METHODS: Fifty-five children receiving HSCT were divided into two groups (aGVHD and non-aGVHD). Body mass index Z-scores (BMI-z), arm muscle area index (AMAI), fat mass index (FMI), and fat-free mass index (FFMI) were measured on the day of transplantation (H0), and on the 30th (H30), 60th (H60), and 100th day (H100) after the transplantation. The correlative factors on body composition were evaluated. RESULTS: In the aGVHD group, the rates of absolute change of BMI-z at H30, H60, and H100 showed a significant increase as compared to that at H0, especially at H30 which was remarkably higher than that of the non-aGVHD group (P = 0.008). AMAI showed a continuous decrease from H0 to H100 in the aGVHD group; also FFMI was found to be lower than that of the non-aGVHD group during the first 100 days after transplantation, however, no significant differences were found between the two groups. At H60 and H100, FFMI in the aGVHD group was lower than that in the non-aGVHD group (P = 0.014, P = 0.032, respectively). Glucocorticoid treatment and the occurrence of mucositis were the key factors for changes in body composition in the aGVHD group. CONCLUSIONS: Changes in body composition are characterized by a lean reduction in body mass and increase in adipose tissues in the early stage of post-transplantation in the aGVHD children. Glucocorticoid treatment and occurrence of mucositis are the two important factors that were found to affect body composition after HSCT.

Effect of explosive noise on gastrointestinal transit and plasma levels of polypeptide hormones.

AIM: To investigate the effect of firing noise on gastrointestinal transit and probe its mechanism by measuring the levels of plasma polypeptide hormones. METHODS: A total of 64 SD rats were randomly divided into a control group and three stimulating groups. Firing noise of different intensity by sub-machine guns was used as inflicting factor. The effect of firing noise on liquid substance gastrointestinal transit and solid substance gastrointestinal transit was observed by measuring the ratio of carbon powder suspension transmitting and barium sticks transmitting respectively. Plasma levels of polypeptide hormones were measured by radio-immunoassay. RESULTS: The noise accelerated gastrointestinal transit of solid food by more than 80 db;and accelerated gastrointestinal transit of liquid food significantly by more than 120 db. Meantime, plasma levels of plasma motilin (MTL)(157.47+/-16.08; 151.90+/-17.08), somatostatin (SS)(513.97+/-88.77; 458.25+/-104.30), substance P (SP)(115.52+/-20.70; 110.28+/-19.96) and vasoactive intestinal peptide (VIP) (214.21+/-63.17; 251.76+/-97.24) remarkably changed also. CONCLUSION: Within a certain intensity range, the firing noise changes the levels of rat plasma gastrointestinal hormones, but the gastrointestinal transit is still normal. Beyond the range, the noise induces plasma hormone levels disturbance and gastrointestinal transit disorder.