Toxoplasma gondii infection in children after allogeneic hematopoietic stem cell transplantation: A case report and literature review

Metagenomic Next-generation Sequencing May be a Tool for Timely Diagnosis of Seronegative and Primary Toxoplasma Infection After Allogeneic Hematopoietic Stem Cell Transplantation: A Case Report and Literature Review

We report a case of Toxoplasma gondii ( T. gondii ) antibody seronegativity in a 14-year-old boy with a primary infection of T. gondii after allogeneic hematopoietic stem cell transplantation for acute T-cell lymphoblastic leukemia who was rapidly diagnosed through metagenomic next-generation sequencing of peripheral blood as well as clinical manifestations. He was successfully cured with timely administration of trimethoprim-sulfamethoxazole due to early diagnosis.

Granulomas in bone marrow biopsies: clinicopathological significance and new perspectives

Bone marrow granulomas in trephine biopsies are a rare and usually incidental finding. Possible causes include infectious (especially tuberculous and rarer non-tuberculous mycobacteria, but also many other bacterial, viral, fungal and parasitic agents) and non-infectious causes (especially medications, autoimmune disease, sarcoidosis, haematological and non-haematological malignancy). Necrotising granulomas are generally suggestive of an infectious aetiology (tuberculosis being the most common), whereas fibrin ring granulomas are associated with Q-fever and Epstein Barr Virus, although exceptions are possible. Every case suspicious for infectious aetiology should undergo further analysis like special staining (Ziehl-Neelsen for acid-fast rods) or molecular studies. The histomorphology should always be clinically correlated. In cases in which no infectious cause can be identified, untargeted metagenomics may represent a valid diagnostic tool that may become standard in the near future for bone marrow diagnostics. In this review, we have analysed the published data from 1956 up to today, and we report aspects of epidemiology, aetiology, diagnostic algorithms, differential diagnosis and the role of metagenomics in bone marrow biopsies with granulomas.

Primary exploring the value of metagenomic next-generation sequencing in detecting pathogenic bacteria of cholangitis with biliary atresia after Kasai operation

PURPOSE

To evaluate the value of metagenomic next-generation sequencing (mNGS) in detecting pathogenic bacteria of cholangitis for patients with biliary atresia after Kasai operation.

METHODS

This study retrospectively analyzed patients of biliary atresia with cholangitis after Kasai operation who were admitted to Xi'an Children's Hospital from July 2019 to December 2021. Both blood culture and mNGS were carried out in all of these patients. We compared the detection rate of pathogenic bacteria, pathogenic bacteria spectrum, test time, inflammatory indicators and liver function. All the patients were followed up for 0.5-3 years to evaluate the onset of cholangitis and the survival status of autologous liver.

RESULTS

This study included total of 30 cholangitis occurred in 25 patients. There were significant differences in the detection rate of pathogenic bacteria [23.3 vs.73.3%, P < 0.05] and the test time [120 (114.5-120) vs.16 (16-21) h, P < 0.001] between the blood culture and mNGS. These two methods showed significant statistical differences in comparing inflammatory indicators (CRP, PCT) and liver function (TB, DB, GGT) before and after anti-infection. Four kinds of bacteria were detected by blood cultures and ten kinds of bacteria were detected by mNGS. Cholangitis occurred 3 times in one case (4%) and twice in three cases (12%). Autologous liver survived in 17 cases (68%).

CONCLUSION

Comparing with traditional blood culture, mNGS is more efficient, convenient and accurate in the detection of pathogens. It provides a new method for accurately detecting pathogenic bacteria of cholangitis after Kasai operation.