Underlying etiologies of prolonged icterus in neonates

Analysis of the intestinal microbiota and profiles of blood amino acids and acylcarnitines in neonates with hyperbilirubinemia

OBJECTIVE

This study aimed to discuss the distinctive features of the intestinal microbiota in neonates with hyperbilirubinemia and to comprehensively analyse the composition of the intestinal microbiota as well as the levels of free amino acids and acylcarnitines in the peripheral blood of neonates experiencing hyperbilirubinemia.

RESULTS

At the phylum level, Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, and Chloroflexi were the five predominant microbial groups identified in both the hyperbilirubinemia and control groups. Alpha diversity analysis, encompassing seven indices, showed no statistically significant differences between the two groups. However, Beta diversity analysis revealed a significant difference in intestinal microbiota structure between the groups. Linear discriminant analysis effect size (LEfSe) indicated a significant reduction in the abundance of Gammaproteobacteria and Enterobacteriaceae within the hyperbilirubinemia group compared to that in the control group. The heatmap revealed that the control group exhibited increased abundances of Escherichia and Bifidobacterium, while the hyperbilirubinemia group exhibited increased levels of Enterococcus and Streptococcus. Regarding blood amino acids and acylcarnitines, there were greater concentrations of citrulline (Cit), arginine (Arg), ornithine (Orn), and valine (Val) in the hyperbilirubinemia group than in the control group. The hyperbilirubinemia group also exhibited significant increases in medium-chain fatty acids (C6, C8), long-chain fatty acids (C18), and free carnitine (C0).

CONCLUSION

By comparing neonates with hyperbilirubinemia to those without, a significant disparity in the community structure of the intestinal microbiota was observed. The intestinal microbiota plays a crucial role in the bilirubin metabolism process. The intestinal microbiota of neonates with hyperbilirubinemia exhibited a certain degree of dysbiosis. The abundances of Bacteroides and Bifidobacterium were negatively correlated with the bilirubin concentration. Therefore, the fact that neonates with hyperbilirubinemia exhibit some variations in blood amino acid and acylcarnitine levels may provide, to a certain degree, a theoretical basis for clinical treatment and diagnosis.

An Implicit Cause of Prolonged Neonatal Jaundice: Vitamin B12 Deficiency

Objective Prolonged jaundice is defined as a serum bilirubin level of more than 5 mg/dL, which persists at postnatal 14 days in term infants and 21 days following birth in preterm infants. Although the underlying causes cannot be found in the majority of prolonged jaundice cases, this may be the first sign of a serious issue. Therefore, this study aimed to evaluate the association between vitamin B12 deficiency and prolonged jaundice in newborns.

Material and Methods This descriptive cross-sectional study was performed in a university hospital between January 1, 2015 and October 1, 2020. All participants consisted of infants who were admitted to the pediatric outpatient clinics. Infants > 35 weeks of gestation and with prolonged jaundice of unknown etiology were included in the study group. The control group consisted of infants > 35 weeks of gestation without prolonged jaundice. Demographic and clinical characteristics and serum vitamin B12 levels were evaluated comparatively.

Results A total of 126 infants, 66 of whom had prolonged jaundice, were included. The mean gestational week of the study group was 38.4 ± 1.8, and the control group was 38.6 ± 1.9 weeks. There was no difference between the groups in terms of demographics and laboratory data. The vitamin B12 level of the study group was significantly lower (median = 170 pg/mL) than the control (median = 268 pg/mL).

Conclusion Based on the findings of this study, vitamin B12 deficiency was thought to be an important cause of prolonged jaundice, and further studies are needed to explain the role of vitamin B12 deficiency in the etiology of prolonged jaundice.

Causative organisms and antimicrobial susceptibility in jaundiced infants with significant bacteriuria

BACKGROUND

Jaundice may be one of the first signs of urinary tract infection (UTI) in infants. The most common pathogen is Escherichia coli. Currently recommended antibiotic treatment for neonatal UTI is ampicillin and an aminoglycoside. Recently, increasing ampicillin and gentamicin resistance in strains of E. coli has been isolated. The aim of this study was to determine causative organisms and antimicrobial susceptibility in jaundiced infants with significant bacteriuria (SB).

METHODS

We evaluated admitted afebrile, asymptomatic infants younger than 1-month old with hyperbilirubinemia (total bilirubin >15 mg/dl) requiring phototherapy between January 2011 and December 2015. A total of 615 asymptomatic jaundiced infants were enrolled. Urinalysis and urine cultures were performed on all jaundiced infants. A urine culture was defined as SB if a single pathogen with more than 105-colony forming units per milliliter (CFU/ml) by sterile urinary collection bag or 104 CFU/ml by catheterization was isolated.

RESULTS

A total of 88 (14.3%) of 615 asymptomatic jaundiced infants had positive urinary culture. E coli was the most common cultured bacteria (40 cases, [45.5%]). Enterococcus faecalis was the second most common bacteria (17 cases, [19.3%]). Seven cases (8.0%) of Streptococcus agalactiae and six cases (6.8%) of Klebsiella pneumoniae were also identified. Ampicillin sensitivity was found in 22.5% of E. coli infections, gentamicin sensitivity was found in 84.2%, and extended-spectrum β-lactamases were found in 7.5%.

CONCLUSION

E. coli was the most common causative organism for infants with SB. We suggest modifying current empiric antibiotics by changing gentamicin to amikacin for neonatal Gram-negative bacterial infections.

Impact of Diagnostic Criteria on UTI Prevalence in Young Infants With Jaundice: A Meta-analysis

BACKGROUND AND OBJECTIVE

Previously reported prevalence of urinary tract infections (UTIs) in infants with jaundice range from <1% to 25%. However, UTI criteria are variable and, as demonstrated in a meta-analysis on UTI prevalence in bronchiolitis, disease prevalence is greatly impacted by disease definition. The objective of this study was to conduct a systemic review and meta-analysis examining the impact of including positive urinalysis (UA) results as a diagnostic criterion on the estimated UTI prevalence in young infants with jaundice.

METHODS

The data sources used were Medline (1946-2020) and Ovid Embase (1976-2020) through January 2020 and bibliographies of retrieved articles. We selected studies reporting UTI prevalence in young infants with jaundice. Data were extracted in accordance with meta-analysis of observational studies in epidemiology guidelines. Random-effects models produced a weighted pooled event rate with 95% confidence intervals (CI).

RESULTS

We screened 526 unique articles by abstract and reviewed 53 full-text articles. We included 32 studies and 16 contained UA data. The overall UTI prevalence in young infants with jaundice from all 32 studies was 6.2% (95% CI, 3.9-8.9). From the 16 studies with UA data, the overall UTI prevalence was 8.7% (95% CI, 5.1-13.2), which decreased to 3.6% (95% CI, 2.0-5.8) with positive UA results included as a diagnostic criterion.

CONCLUSIONS

The estimated UTI prevalence in young infants with jaundice decreases substantially when UA results are incorporated into the UTI definition. Due to the heterogeneity of study subjects' ages and definitions of jaundice, positive UA results, and UTI, there is uncertainty about the exact prevalence and about which infants with hyperbilirubinemia warrant urine testing.

Factors Affecting Prevalence of Urinary Tract Infection in Neonates with Unexplained Hyperbilirubinemia: A Systematic Review and Meta-Analysis Study in Iran

Background:

The prevalence and risk factors of urinary tract infection (UTI) in neonates with unexplained hyperbilirubinemia are not studied thoroughly. Since the prevalence of UTI is highly variable in different areas and countries, this study aimed to review the existing data of Iranian neonates with UTI presented with unexplained hyperbilirubinemia.

Methods:

This study is a meta-analysis of Iranian newborns with unexplained hyperbilirubinemia. We identified all studies indexed in international (Web of Science, PubMed, Scopus, Google Scholar) and national (Science Information Database, Magiran) databases from 2000–2018. Search terms included: Urinary Tract Infections OR UTI AND urine OR culture OR microbio, jaundice OR icter OR hyperbili, AND Iran.

Results:

Overall, 4210 neonates from 17 studies were included. The pooled prevalence of UTI in neonates with unexplained hyperbilirubinemia was 6.81% (95% CI: 4.86–8.77). Considering the subgroups analyses; the prevalence of UTI was higher in the prolonged vs. not-prolonged state (8.34% vs. 4.00%), low birth weight vs. normal birth weight (7.81% vs. 4.51%), and exclusive vs. non-exclusive breastfeeding (8.84% vs. 4.72%). Male gender and low birth weight increased the risk of UTI about two times compared to the female gender and normal birth weight, respectively. The results of the analyses in neonates with unconjugated hyperbilirubinemia also showed the above-mentioned subgroup differences.

Conclusion:

Due to considerable prevalence of UTI in neonates with unexplained hyperbilirubinemia and risk factors in this age group, investigation for UTI is essential for the workup in this situation.

[Characteristics of gut microbiota and its association with the activity of β-glucuronidase in neonates with hyperbilirubinemia]

OBJECTIVE

To study the characteristics of gut microbiota and its association with the activity of β-glucuronidase (β-GD) in neonates with hyperbilirubinemia.

METHODS

A total of 50 neonates with hyperbilirubinemia who were admitted in January to December, 2018, were enrolled as the hyperbilirubinemia group, and 30 neonates without hyperbilirubinemia were enrolled as the control group. The 16S rRNA high-throughput sequencing method was used to compare gut microbiota between the two groups. The phenolphthalein-glucuronic acid substrate method was used to measure the activity of β-GD in the intestinal tract of neonates with hyperbilirubinemia before and after treatment.

RESULTS

The comparison of the distribution of gut microbiota at the genus level showed a significant difference in the abundance of 52 bacteria between the hyperbilirubinemia and control groups before treatment (P < 0.05), as well as a significant difference in the abundance of 42 bacteria between the hyperbilirubinemia group on day 3 after treatment and the control group on day 3 after enrollment (P < 0.05). After treatment, the hyperbilirubinemia group had significant reductions in the content of Escherichia and Staphylococcus in the intestinal tract (P < 0.05) and the activity of β-GD in feces (P < 0.05). The activity of β-GD in feces was positively correlated with the abundance of Staphylococcus and Escherichia before and after treatment in the neonates with hyperbilirubinemia (r_s=0.5948-0.7245, P < 0.01).

CONCLUSIONS

There are differences in gut microbiota between the neonates with hyperbilirubinemia and those without hyperbilirubinemia. The activity of β-GD in feces is positively correlated with the abundance of Staphylococcus and Escherichia in neonates with hyperbilirubinemia. Gut microbiota may affect the development of neonatal hyperbilirubinemia by regulating the activity of β-GD. The determination and analysis of gut microbiota and β-GD activity may have certain clinical significance for the early assessment of the development of neonatal hyperbilirubinemia.

Prevalence of G6PD deficiency in Iranian neonates with jaundice: a systematic review and meta-analysis

OBJECTIVES

This systematic review and meta-analysis study aimed to estimate the overall prevalence of Glucose-6-phosphate dehydrogenase (G6PD) deficiency in neonates with jaundice who were admitted to hospitals in Iran.

MATERIALS AND METHODS

In this systematic review and meta-analysis, we searched PubMed/Medline, Scopus, ISI Web of Sciences, and Iranian Local databases up to December 2019.We calculated Prevalence and 95% Confidence Interval (95% CI) of G6PD deficiency as summary measures. We conducted subgroup analysis based on the sex and quality of studies, while meta-regression were applied for investigating the effect of years of studies and years of publication on the pooled prevalence. We applied sensitivity analysis to investigate the effect of excluding each study on the pooled prevalence estimation.

RESULTS

The total sample size was 9799 people. The pooled prevalence of G6PD deficiency among neonates with jaundice in Iran was 7.0% (95% CI: 5.5-8.5%). The results of subgroup analysis showed that, pooled prevalence of G6PD deficiency among male neonate (12.1%, 95%CI: 7.6-16.7%) was more prevalent that female (3.00%, 95%CI: 1.1-4.9%). Based on the sensitivity analysis, lower and higher pooled prevalence of G6PD deficiency was observed 5.8% (95%CI: 4.7-6.9%) and 7.3% (95%CI: 5.7-8.8%) respectively by excluding each study.

CONCLUSION

The overall prevalence of G6PD deficiency was 7% in Iranian neonates with Jaundice. Prevalence was high in male and early hours of life. We recommend screening test for G6PD deficiency in neonates to prevent its complications.

Etiology and therapeutic management of neonatal jaundice in Iran: a systematic review and meta-analysis

BACKGROUND

Jaundice is a life-threatening disorder in the neonates. In the present study, we aimed to assess systematically available evidence on causes and management of jaundice in Iranian newborn patients.

METHODS

We searched the databases of PubMed, Web of Sciences, Scopus and Google Scholar for English articles published since inception until May 2019. A search was also done for Persian articles in Magiran and Scientific Information Database. Studies were evaluated based on predefined criteria by two reviewers. Data analysis was performed by STATA software.

RESULTS

A total of 33 articles were finally included. The overall pooled prevalence of causes of jaundice among Iranian neonates was as follows: ABO blood groups incompatibility, 16.9% [95% confidence interval (CI) 10.9-22.8]; Rh blood group incompatibility, 4% (95% CI 2.5-5.5); ABO and Rh blood groups incompatibility, 3.6% (95% CI 0-7.7); glucose-6-phosphate dehydrogenase (G6PD) deficiency, 6.3% (95% CI 5.1-7.5); infection, 6.6% (95% CI 5.2-8.1); hypothyroidism, 4.2% (95% CI 0.1-8.3); infant of diabetic mother: 2.3% (95% CI 0.1-4.5); unknown, 50.7% (95% CI 33.4-68); cephalohematoma, 0.6% (95% CI 0.3-0.9). Regarding treatment of icterus, seven and eight articles were found on phototherapy and exchange transfusion, respectively. In five studies, all patients underwent phototherapy, but rate of exchange transfusion use was between 6.6% and 50.9%.

CONCLUSIONS

According to the results, unknown factors were the most common causes of icterus in Iranian neonates, followed by ABO blood groups incompatibility, infections and G6PD deficiency. By the way, phototherapy and exchange transfusion were found as therapeutic choices of neonatal jaundice.

Is screening for urine infection in well infants with prolonged jaundice required? Local review and meta-analysis of existing data

BACKGROUND

The National Institute for Health and Care Excellence (NICE) neonatal jaundice guidance recommends a urine culture for investigation of babies with prolonged jaundice. However, the evidence cited for this guidance is limited. We aimed to review local data and the existing literature to identify evidence to either support or refute this guidance.

METHOD

We retrospectively reviewed 3 years of urine cultures from our outpatient prolonged jaundice clinic. We then conducted literature review with meta-analysis of studies presenting original data on urine tract infection (UTI) rates in jaundiced and prolonged jaundiced babies.

RESULTS

From our local data, none of the 279 patients met our unit clinical criteria for UTI. Literature review revealed considerable differences worldwide in UTI rates in both jaundiced and prolonged jaundiced cases. Using pooled data from our literature review and our local population, the incidence of UTI in prolonged jaundiced babies is 0.21% (95% CI 0.0% to 0.73%) in the UK. This is significantly lower than the figure indicated from the data from elsewhere in the world, 8.21% (95% CI 4.36% to 13.0%).

CONCLUSIONS

The findings both from our local data and the current literature do not support the practice of routine screening for urine infection in well babies with prolonged jaundice. In view of the above, we no longer include urine culture in screening of well infants with prolonged jaundice. We hope that NICE will re-examine the evidence and recommend changes to their guidance on the role of routine screening for urine infection in babies with prolonged jaundice.