Aims: This study aimed to investigate the changes in gut microbiota in iron-overload thalassemia and the roles of an iron chelator on gut dysbiosis/inflammation, and metabolites, including short-chain fatty acids (SCFAs) and trimethylamine N-oxide (TMAO). Main methods: Adult male C57BL/6 mice both wild-type (WT: n = 15) and heterozygous beta-thalassemia (BKO: n = 15) were fed on either a normal (ND: n = 5/group) or a high-iron diet for four months (HFe: n = 10/group). HFe-treated WT and HFe-treated BKO groups were further subdivided into two subgroups and each subgroup given either vehicle (n = 5/subgroup) or deferiprone (n = 5/subgroup) during the last month. Gut microbiota profiles, gut barrier characteristics, levels of proinflammatory cytokines, and plasma SCFAs and TMAO were determined at the end of the study. Key findings: HFe-fed WT mice showed distinct gut microbiota profiles from those of ND-fed WT mice, whereas HFe-fed BKO mice showed slightly different gut microbiota profiles from ND-fed BKO. Gut inflammation and barrier disruption were found only in HFe-fed BKO mice, however, an increase in plasma TMAO levels and decreased levels of SCFAs were observed in both WT and BKO mice with HFe-feeding. Treatment with deferiprone, gut dysbiosis and disturbance of metabolites were attenuated in HFe-fed WT mice, but not in HFe-fed BKO mice. Increased Verrucomicrobia and Ruminococcaceae were associated with the beneficial effects of deferiprone. Significance: Iron-overload leads to gut dysbiosis/inflammation and disturbance of metabolites, and deferiprone alleviates those conditions more effectively in WT than in those that are thalassemic.

Salmonella entericaserovar Typhimurium (S. Typhimurium [STM]) is a leading cause of nontyphoidal salmonellosis (NTS) worldwide. The pathogenesis of NTS has been studied extensively using a streptomycin-pretreated mouse colitis model with the limited numbers of laboratory STM strains. However, the pathogenicity of the clinically isolated STM (STMC) strains endemic in Thailand in mice has not been explored. The aim of this study was to compare the pathogenicity of STMC strains collected from Northern Thailand with the laboratory STM (IR715) in mice. Five STMC isolates were obtained from the stool cultures of patients with acute NTS admitted to Maharaj Nakorn Chiang Mai Hospital in 2016 and 2017. Detection of virulence genes and sequence type (ST) of the strains was performed. Female C57BL/6 mice were pretreated with streptomycin sulfate 1 day prior to oral infection with STM. On Day 4 postinfection, mice were euthanized, and tissues were collected to analyze the bacterial numbers, tissue inflammation, and cecal histopathological score. We found that all five STMC strains are ST34 and conferred the same or reduced pathogenicity compared with that of IR715 in mice. A strain-specific effect of ST34 on mouse gut colonization was also observed. Thailand STM ST34 exhibited a significant attenuated systemic infection in mice possibly due to the lack ofspvABC-containing virulence plasmid.

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.