Effects of Probiotics on Preterm Infant Gut Microbiota Across Populations: A Systematic Review and Meta-Analysis

Microbiota in early life is closely associated with the health of infants, especially premature ones. Probiotics are important drivers of gut microbiota development in preterm infants; however, there is no consensus regarding the characteristics of specific microbiota in preterm infants receiving probiotics. In this study, we performed a meta-analysis of 5 microbiome data sets (1816 stool samples from 706 preterm infants) to compare the gut microbiota of preterm infants exposed to probiotics with that of preterm infants not exposed to probiotics across populations. Despite study-specific variations, we found consistent differences in gut microbial composition and predicted functional pathways between the control and probiotic groups across different cohorts of preterm infants. The enrichment of Acinetobacter, Bifidobacterium, and Lactobacillus spp and the depletion of the potentially pathogenic bacteria Finegoldia, Veillonella, and Klebsiella spp. were the most consistent changes in the gut microbiota of preterm infants supplemented with probiotics. Probiotics drove microbiome transition into multiple preterm gut community types, and notably, preterm gut community type 3 had the highest α-diversity, with enrichment of Bifidobacterium and Bacteroides spp. At the functional level, the major predicted microbial pathways involved in peptidoglycan biosynthesis consistently increased in preterm infants supplemented with probiotics; in contrast, the crucial pathways associated with heme biosynthesis consistently decreased. Interestingly, Bifidobacterium sp. rather than Lactobacillus sp. gradually became dominant in gut microbiota of preterm infants using mixed probiotics, although both probiotic strains were administered at the same dosage. Taken together, our meta-analysis suggests that probiotics contribute to reshaping the microbial ecosystem of preterm infants at both the taxonomic and functional levels of the bacterial community. More standardized and relevant studies may contribute to better understanding the crosstalk among probiotics, the gut microbiota, and subsequent disease risk, which could help to give timely nutritional feeding guidance to preterm infants. This systematic review and meta-analysis was registered at PROSPERO (https://www.crd.york.ac.uk/PROSPERO/) as CRD42023447901.

An Overview of Type B Lactic Acidosis Due to Thiamine (B1) Deficiency

Type B lactic acidosis can occur secondary to several factors, including thiamine deficiency, and is not as common as type A. Recognizing thiamine deficiency-associated lactic acidosis is challenging because serum thiamine concentrations are not routinely obtained, and a thorough and specific history is necessary for clinicians to suspect thiamine deficiency as a root cause. Furthermore, the appropriate dose and duration of thiamine treatment are not well defined. Untreated thiamine deficiency-associated lactic acidosis can lead to critical illness requiring lifesaving extracorporeal therapies. Additionally, if thiamine and glucose are not administered in an appropriate sequence, Wernicke encephalopathy or Korsakoff syndrome may occur. This review aims to summarize therapeutic treatment for thiamine deficiency-associated lactic acidosis, based on case reports/series and nutritional guidance. After a literature search of the PubMed database, 63 citations met inclusion criteria, of which 21 involved pediatric patients and are the focus of this review. -Citations describe dosing regimens ranging from 25 to 1000 mg of intravenous (IV) thiamine as a single dose, or multiple daily doses for several days. Specific guidance for critically ill adults recommends a thiamine range of 100 mg IV once daily to 400 mg IV twice daily. Although there are no specific recommendations for the pediatric population, given the relative safety of thiamine administration, its low cost, and our review of the literature, treatment with thiamine 100 to 200 mg IV at least once is supported, with ongoing daily doses based on clinical response of the patient, regardless of age.

Severe Lactic Acidosis Caused by Thiamine Deficiency in a Child with Relapsing Acute Lymphoblastic Leukemia: A Case Report

Lactic acidosis is characterized by an excessive production of lactic acid or by its impaired clearance. Thiamine deficiency is an uncommon cause of lactic acidosis, especially in countries where malnutrition is rare. We describe the case of a 5-year-old boy who presented with a central nervous system relapse of acute lymphoblastic leukemia. During the chemotherapy regimen, the patient developed drug-induced pancreatitis with paralytic ileus requiring prolonged glucosaline solution infusion. In the following days, severe lactic acidosis (pH 7.0, lactates 253 mg/dL, HCO3- 8 mmol/L) was detected, associated with hypoglycemia (42 mg/dL) and laboratory signs of acute liver injury. Due to the persistent hypoglycemia, the dextrose infusion was gradually increased. Lactates, however, continued to raise, so continuous venovenous hemodiafiltration was started. While lactates initially decreased, 12 h after CVVHDF suspension, they started to raise again. Assuming that it could have been caused by mitochondrial dysfunction due to vitamin deficiency after prolonged fasting and feeding difficulties, parenteral nutrition and thiamine were administered, resulting in a progressive reduction in lactates, with the normalization of pH during the next few hours. In the presence of acute and progressive lactic acidosis in a long-term hospitalized patient, thiamine deficiency should be carefully considered and managed as early as possible.

Vitamin B1 Deficiency and Perimyocarditis Fulminans: A Case Study of Shoshin Syndrome in a Woman Following an Unbalanced Dietary Pattern Followed by a Literature Review

(1) Background: vitamin B1 level depletion, known as a beriberi syndrome, can lead to severe cardiovascular complications, from which perimyocarditis fulminans is one of the most severe. (2) Methods: this is a retrospective case study that includes an adult patient with clinical presentations of acute heart failure (HF) symptoms following perimyocarditis on the grounds of thiamine deficiency. (3) Results: A 49-year-old woman presented with acute HF symptoms due to perimyocarditis. The patient suddenly developed refractory cardiogenic shock with metabolic acidosis requiring maximal medical management, including an intra-aortic balloon pump and extracorporeal membrane oxygenation. Due to additional peripheral polyneuropathy, beriberi disease was suspected after excluding other possible causes of the patient's condition. After administration of vitamin B1, clinical improvement in the patient's condition and the resolution of metabolic abnormalities were observed, which ultimately confirmed the diagnosis of Shoshin syndrome caused by the implementation of a gluten-free diet without indications for its adherence. (4) Conclusions: Fulminant beriberi disease, although considered rare, is a life-threatening condition and should always be included in the differential diagnosis of critically ill patients, notably those with malnutrition. An unbalanced diet can be detrimental and have severe consequences, i.e., perimyocarditis fulminans. However, treatment with thiamine can significantly improve the patient's cardiac function and restore hemodynamic and metabolic parameters.

Thiamine-responsive, life-threatening, pulmonary hypertensive crisis with encephalopathy in young infants: A case series

OBJECTIVE

Thiamine (Vitamin B1) deficiency (TD), although reduced in incidence, is still seen in infants. We describe a rarely reported form of infantile TD with life-threatening pulmonary hypertensive crisis and severe encephalopathy, with dramatic response to thiamine supplementation.

METHODS

Study design: Descriptive case series. Six young infants with mean age 76 days (range 1-3 months), manifesting rapidly progressive encephalopathy and cardio-pulmonary arrest were included. All infants underwent cardiac, neuroimaging and metabolic evaluations.

RESULTS

All six infants had similar presentation with severe pulmonary arterial hypertension (PAH), hypotensive shock, metabolic acidosis and severe encephalopathy. All infants were exclusively breast-fed. Thiamine treatmwnt resulted in dramatic improvement in haemodynamic and neurological function in all the infants. There were no major neurological deficits on follow up.

CONCLUSION

A high index of suspicion is warranted for this rarely described form of TD, as early identification helps in preventing mortality and morbidity.

Pediatric thiamine deficiency disorders in high-income countries between 2000 and 2020: a clinical reappraisal

Often thought to be a nutritional issue limited to low- and middle-income countries (LMICs), pediatric thiamine deficiency (PTD) is perceived as being eradicated or anecdotal in high-income countries (HICs). In HICs, classic beriberi cases in breastfed infants by thiamine-deficient mothers living in disadvantaged socioeconomic conditions are thought to be rare. This study aims to assess PTD in HICs in the 21st century. Literature searches were conducted to identify case reports of PTD observed in HICs and published between 2000 and 2020. The analyzed variables were age, country, underlying conditions, clinical manifestations of PTD, and response to thiamine supplementation. One hundred and ten articles were identified, totaling 389 PTD cases that were classified into four age groups: neonates, infants, children, and adolescents. Eleven categories of PTD-predisposing factors were identified, including genetic causes, lifestyle (diabetes, obesity, and excessive consumption of sweetened beverages), eating disorders, cancer, gastrointestinal disorders/surgeries, critical illness, and artificial nutrition. TD-associated hyperlactatemia and Wernicke encephalopathy were the most frequent clinical manifestations. The circumstances surrounding PTD in HICs differ from classic PTD observed in LMICs and this study delineates its mutiple predisposing factors. Further studies are required to estimate its magnitude. Awareness is of utmost importance in clinical practice.

Severe Lactic Acidosis in a Critically Ill Child: Think About Thiamine! A Case Report

In this article, we presented a teenager, in maintenance chemotherapy for leukemia, who was admitted for digestive symptoms related to a parasitic infection and required nutritional support with parenteral nutrition. After 6 weeks, his condition worsened with refractory shock of presumed septic origin, necessitating extracorporeal membrane oxygenation. Despite hemodynamic stabilization, his lactic acidosis worsened until thiamine supplementation was started. Lactate normalized within 12 hours. Thiamine is an essential coenzyme in aerobic glycolysis, and deficiency leads to lactate accumulation through anaerobic glycolysis. Thiamine deficiency is uncommon in the pediatric population. However, it should be considered in patients at risk of nutritional deficiencies with lactic acidosis of unknown origin.

Influence of Glucose Dosage in Parenteral Nutrition on Body Thiamine Levels in Rats

The objective of this study was to determine the relationship between glucose dosage in parenteral nutrition and reductions in levels of body thiamine in rats. Vitamin-free infusions with differing amounts of glucose were administered to normal or thiamine-deficient rats for 5 days, after which urinary thiamine excretion and the amounts of thiamine in the blood, liver, brain, and skeletal muscles were measured. The total energy dosage was set at three levels (98, 140, and 196 kcal/kg), and the dose of amino acids was constant among all groups. Urinary thiamine excretions on Day 5 decreased with increasing glucose dosage in the infusions. In normal rats, the amount of thiamine in the blood and all organs decreased compared with the diet group; however, no significant differences were found among the infusion groups. In thiamine-deficient rats, on the other hand, the amount of thiamine in the liver and skeletal muscles did not differ significantly among infusion groups; however, the amount of thiamine in the brain and blood decreased with increasing glucose dosage. An organ-specific correlation was found between glucose dosage in infusions and reductions in levels of thiamine. To prevent thiamine deficiencies from affecting the central nervous system, greater caution must be exercised during high-caloric parenteral nutrition. However, a constant supply of thiamine seemed to be essential, irrespective of the amount of energy supplied via parenteral nutrition, to maintain a sufficient level of thiamine in the body.

Severe lactic acidosis in an extremely low birth weight infant due to thiamine deficiency

BACKGROUND

In this case report, we present a preterm newborn with persistent lactic acidosis who received total parenteral nutrition (TPN) that lacked thiamine.

CASE PRESENTATION

A 28-week-old, 750 g female infant was born with an Apgar score of 8 at the 5th minute. Umbilical cord blood gas levels, including lactate level, were normal, and she was admitted to our neonatal intensive care unit (NICU). Achieving full enteral feeding was not possible due to gastric residues and abdominal distention, making the patient dependent on TPN during the first 2 weeks of life. An insidious increase in lactic acid levels and uncompensated metabolic acidosis were apparent from the 23rd day of life. Severe metabolic acidosis was persistent despite massive doses of bicarbonate. The acidosis resolved dramatically within 6 h when the patient was administered with thiamine.

CONCLUSIONS

Although TPN is life saving in the NICU, meticulous attention must be paid to provide all essential macro- and micro-nutrients.

Thiamine Deficiency Leading to Refractory Lactic Acidosis in a Pediatric Patient

Thiamine plays a critical role in energy metabolism. Critically ill children and adults may develop thiamine deficiency with ultimately increased mortality due to potentially irreversible consequences of severe type B lactic acidosis. We report a case of an unvaccinated term neonate with malignant pertussis requiring extracorporeal membrane oxygenation and continuous renal replacement therapy, who developed profound lactic acidosis of unknown etiology. After countless evaluations for likely causes, the patient was ultimately determined to have thiamine deficiency and her acidosis resolved rapidly with vitamin supplementation.