Cholangiocarcinoma (CCA) is a common hepatobiliary cancer in East and Southeast Asia. The data of microbiota contribution in CCA are still unclear. Current available reports have demonstrated that an Opisthorchis viverrini (OV) infection leads to dysbiosis in the bile duct. An increase in the commensal bacteria Helicobacter spp. in OV-infected CCA patients is associated with bile duct inflammation, severity of bile duct fibrosis, and cholangiocyte proliferation. In addition, secondary bile acids, major microbial metabolites, can mediate cholangiocyte inflammation and proliferation in the liver. A range of samples from CCA patients (stool, bile, and tumor) showed different degrees of dysbiosis. The evidence from these samples suggests that OV infection is associated with alterations in microbiota and could potentially have a role in CCA. In this comprehensive review, reports from in vitro, in vivo, and clinical studies that demonstrate possible links between OV infection, microbiota, and CCA pathogenesis are summarized and discussed. Understanding these associations may pave ways for novel potential adjunct intervention in gut microbiota in CCA patients.

Intestinal bacterial flora of febrile neutropenic patients had significantly diverse. However, there were scanty reports of microbiota alteration of adult patients with acute myeloid leukemia (AML). Stool samples of each treatment-naïve AML patient were collected at the day before induction chemotherapy initiation (pretreatment), first day of neutropenic fever and first day of bone marrow recovery. Bacterial DNA was extracted from stool and sequenced bacterial 16s ribosomal RNA genes by next-generation sequencing. Relative abundance, overall richness, Shannon’s diversity index and Simpson’s diversity index were calculated. Ten cases of AML patients (4 men and 6 women) were included with median age of 39 years (range: 19-49) and all of patients developed febrile neutropenia. Firmicutes were dominated over the period of neutropenic fever and subsequent declined after bone marrow recovery contrast to Bacteroidetes and Proteobacteria. Enterococcus was more abundant at febrile neutropenia period compared to pretreatment while Bacteroides and Escherichia was notably declined during the febrile neutropenia. At the operational taxonomic units (OTUs) level, there was significant higher level of overall richness of pretreatment period than febrile neutropenic episode. Both of the diversity indexes of Shannon and Simpson were considerably decreased at febrile neutropenic period. Adult AML patients with first episode of febrile neutropenia after initial intensive chemotherapy demonstrated the significant decrease of gut microbiota diversity and the level of diversity consistently remained constant despite of bone marrow recovery.