Methods for exploring the faecal microbiome of premature infants: a review

The premature infant gut microbiome plays an important part in infant health and development, and recognition of the implications of microbial dysbiosis in premature infants has prompted significant research into these issues. The approaches to designing investigations into microbial populations are many and varied, each with its own benefits and limitations. The technique used can influence results, contributing to heterogeneity across studies. This review aimed to describe the most common techniques used in researching the preterm infant microbiome, detailing their various limitations. The objective was to provide those entering the field with a broad understanding of available methodologies, so that the likely effects of their use can be factored into literature interpretation and future study design. We found that although many techniques are used for characterising the premature infant microbiome, 16S rRNA short amplicon sequencing is the most common. 16S rRNA short amplicon sequencing has several benefits, including high accuracy, discoverability and high throughput capacity. However, this technique has limitations. Each stage of the protocol offers opportunities for the injection of bias. Bias can contribute to variability between studies using 16S rRNA high throughout sequencing. Thus, we recommend that the interpretation of previous results and future study design be given careful consideration

The bacterial gut microbiome of probiotic-treated very-preterm infants: changes from admission to discharge

Background: Preterm birth is associated with the development of acute and chronic disease, potentially, through the disruption of normal gut microbiome development. Probiotics may correct for microbial imbalances and mitigate disease risk. Here, we used amplicon sequencing to characterise the gut microbiome of probiotic-treated premature infants. We aimed to identify and understand variation in bacterial gut flora from admission to discharge and in association with clinical variables. Methods: Infants born <32 weeks gestation and <1500 g, and who received probiotic treatment, were recruited in North Queensland Australia. Meconium and faecal samples were collected at admission and discharge. All samples underwent 16S rRNA short amplicon sequencing, and subsequently, a combination of univariate and multivariate analyses. Results: 71 admission and 63 discharge samples were collected. Univariate analyses showed significant changes in the gut flora from admission to discharge. Mixed-effects modelling showed significantly lower alpha diversity in infants diagnosed with either sepsis or retinopathy of prematurity (ROP) and those fed formula. In addition, chorioamnionitis, preeclampsia, sepsis, necrotising enterocolitis and ROP were also all associated with the differential abundance of several taxa. Conclusions: The lower microbial diversity seen in infants with diagnosed disorders or formula-fed, as well as differing abundances of several taxa across multiple variables, highlights the role of the microbiome in the development of health and disease. This study supports the need for promoting healthy microbiome development in preterm neonates

To Probiotic or Not to Probiotic: A Metagenomic Comparison of the Discharge Gut Microbiome of Infants Supplemented With Probiotics in NICU and Those Who Are Not

Background: Preterm birth is associated with the development of both acute and chronic disease, and the disruption of normal gut microbiome development. Recent studies have sought to both characterize and understand the links between disease and the microbiome. Probiotic treatment may correct for these microbial imbalances and, in turn, mitigate disease. However, the criteria for probiotic supplementation in NICU's in North Queensland, Australia limits its usage to the most premature (<32 weeks gestation) and small for gestational age infants (<1,500 g). Here we use a combination of amplicon and shotgun metagenomic sequencing to compare the gut microbiome of infants who fulfill the criteria for probiotic-treatment and those who do not. The aims of this study were to determine if probiotic-supplemented preterm infants have significantly different taxonomic and functional profiles when compared to non-supplemented preterm infants at discharge. Methods: Preterm infants were recruited in North Queensland, Australia, with fecal samples collected just prior to discharge (36 ± 0.5 weeks gestation), to capture potential changes that could be probiotic induced. All samples underwent 16S rRNA gene amplicon sequencing, with a subset also used for shotgun metagenomics. Mixed effects models were used to assess the effect of probiotics on alpha diversity, beta diversity and taxonomic abundance, whilst accounting for other known covariates. Results: Mixed effects modeling demonstrated that probiotic treatment had a significant effect on overall community composition (beta diversity), characterized by greater alpha diversity and differing abundances of several taxa, including Bifidobacterium and Lactobacillus, in supplemented infants. Conclusion: Late preterm-infants who go without probiotic-supplementation may be missing out on stabilizing-effects provided through increased alpha diversity and the presence of commensal microbes, via the use of probiotic-treatment. These findings suggest that late-preterm infants may benefit from probiotic supplementation. More research is needed to both understand the consequences of the differences observed and the long-term effects of this probiotic-treatment

Paediatric melioidosis in North Queensland, Australia

Aim: to review admissions to the hospital due to Paediatric Melioidosis over a 10 year period.\ud \ud Methods: This was a retrospective chart review of all paediatric patients admitted to Townsville Hospital between 1996 and 2006 that were proven to have positive cultures for B. pseudomallei. Details were obtained from the Microbiology Department of Townsville Hospital.\ud \ud Results: Between 1996 and 2006, there were 150 cases of culture-confirmed melioidosis in North Queensland. Of these, eight (5.3%) were in children aged under 16 years. There were three deaths in this group. Three patients developed neurological melioidosis and there were no cases of parotid involvement. In our series, neurological melioidosis appeared to be statistically more significant in children compared with adults.\ud \ud Conclusion: Melioidosis is an uncommon paediatric infection in Australia. In our series, neurological melioidosis appeared to be common in children compared with adults with devastating sequelae. The reasons for this remain unclear

Identification of risk factors and evaluation of digital funduscopic screening for retinopathy of prematurity in a regional neonatal unit in Australia

Objectives: To identify risk factors significantly associated with retinopathy of prematurity (ROP) and evaluate the usefulness of digital funduscopy for ROP screening in a regional neonatal unit in Townsville, Australia.\ud \ud Method: This is a retrospective study. Basic data was retrieved from the department's prospectively maintained database and stored in the digital camera (Retcam) data storage device. ROP candidates were defined as babies who were born with a birth weight at or less than 1250 g and/or, born at or before 28 weeks.\ud \ud Results: One hundred babies satisfied the criteria for inclusion into the study. There were 44 male neonates. Birth weights ranged from 470-1342g (mean 986±177). Female babies were significantly smaller than males (p0.05). Twenty three babies had ROP. Retinal images from 6 babies were sent for remote expert opinion and 2 babies were transferred for treatment.\ud \ud Conclusions: ROP is significantly associated with prematurity. More clinical trials on bigger cohorts are necessary to evaluate digital funduscopy on ROP screening

The IUGR infant: a case study and associated problems with IUGR infants

[Extract] The terms intrauterine growth restriction (IUGR) and small for gestational age (SGA) are frequently encountered in the neonatal population. It is the second cause of perinatal mortality after prematurity (Mandruzzato et al., 2008), estimated to be a contributing factor in 52% of stillbirths.\ud \ud Foetal growth restriction is a multifactoral condition that may be foetal, maternal, genetic or environmental in origin, (See Table 1 & Fig. 2)

Neurodevelopmental outcomes at 2 years of age of premature neonates in Regional Queensland, Australia

The survival rate of premature neonates has increased over the past decade with infants surviving at an earlier gestational age (GA) and lower birth weights (BW) than previously recorded. Premature neonate's neurodevelopmental outcomes are influenced by many factors including GA, BW and neurological insult. Previous research suggests that almost half of premature neonates experience mild, moderate or severe developmental delay including academic, psychosocial and mental health difficulties. Recently, The Townsville Hospital (TTH) Neonatal Unit (North Queensland, Australia), a regional tertiary nursery, has established a follow-up clinic to assess neurodevelopmental outcomes of graduates at 2 years corrected age. The current study explored neurodevelopmental outcomes of neonates under 1500gms BW or less than 32 weeks GA. Forty-three 2 year-old graduates met criteria for the study and were assessed using the Bayley Scales of Infant and Toddler Development, 3rd edition (Bayley-III; Bayley, 2005) between December 2011 and April 2013. The Bayley-III measures cognitive, motor, language, social-emotional development and adaptive behaviours. Results indicated that GA significantly predicted positive adaptive behaviours, but not other developmental outcomes, however BW was not significantly correlated to any of the developmental outcomes. Non-parametric statistical analysis showed neonates with neurological changes identified via cranial ultrasound during their admission to the unit demonstrated significantly poorer cognitive and language development than those with no neurological changes. Further, neonates who had surgery during admission had significantly poorer cognitive, language and social-emotional development at age 2 years. Results of this study has implications for providing support and early intervention services to low gestational age neonates to improve their adaptive behaviours, or daily living skills. Further, neonates with neurological changes will also require additional support to enhance cognitive and language functioning, and social-emotional regulation skills. These findings are particularly important in the context of earlier surviving neonates

Fresh Perspectives on Hospital-Acquired Neonatal Skin Injury Period Prevalence From a Multicenter Study

The objective of this study was to explore neonatal skin injury period prevalence, classification, and risk factors. Skin injury period prevalence over 9 months and χ2, Mann-Whitney U, and independent-samples t tests compared injured and noninjured neonates, with P values less than .05 considered statistically significant. Injury prediction models were developed using Classification and Regression Tree (CART) analysis for the entire cohort and separately for those classified as high or low acuity. The study took place in 3 Australian and New Zealand units. Neonates enrolled (N = 501) had a mean birth gestational age of 33.48 ± 4.61 weeks and weight of 2138.81 ± 998.92 g. Of the 501 enrolled neonates, 206 sustained skin injuries (41.1%), resulting in 391 injuries to the feet (16.4%; n = 64), cheek (12.5%; n = 49), and nose (11.3%; n = 44). Medical devices were directly associated with 61.4% (n = 240) of injuries; of these medical devices, 50.0% (n = 120) were unable to be repositioned and remained in a fixed position for treatment duration. The strongest predictor of skin injury was birth gestation of 30 weeks or less, followed by length of stay of more than 12 days, and birth weight of less than 1255 g. Prediction for injury based on illness acuity identified neonates less than 30 weeks' gestation and length of stay more than 39 days were at a greater risk (high acuity), as well as neonates less than 33 weeks' gestation and length of stay of more than 9 days (low acuity). More than 40% of hospitalized neonates acquired skin injury, of which the majority skin injuries were associated with medical devices required to sustain life. Increased neonatal clinician education and improved skin injury frameworks, informed by neonatal epidemiological data, are vital for the development of effective prevention strategies

Fresh perspectives on hospital-acquired neonatal skin injury period prevalence from a multicenter study: length of stay, acuity, and incomplete course of antenatal steroids

The objective of this study was to explore neonatal skin injury period prevalence, classification, and risk factors. Skin injury period prevalence over 9 months and χ2, Mann-Whitney U, and independent-samples t tests compared injured and noninjured neonates, with P values less than .05 considered statistically significant. Injury prediction models were developed using Classification and Regression Tree (CART) analysis for the entire cohort and separately for those classified as high or low acuity. The study took place in 3 Australian and New Zealand units. Neonates enrolled (N = 501) had a mean birth gestational age of 33.48 ± 4.61 weeks and weight of 2138.81 ± 998.92 g. Of the 501 enrolled neonates, 206 sustained skin injuries (41.1%), resulting in 391 injuries to the feet (16.4%; n = 64), cheek (12.5%; n = 49), and nose (11.3%; n = 44). Medical devices were directly associated with 61.4% (n = 240) of injuries; of these medical devices, 50.0% (n = 120) were unable to be repositioned and remained in a fixed position for treatment duration. The strongest predictor of skin injury was birth gestation of 30 weeks or less, followed by length of stay of more than 12 days, and birth weight of less than 1255 g. Prediction for injury based on illness acuity identified neonates less than 30 weeks' gestation and length of stay more than 39 days were at a greater risk (high acuity), as well as neonates less than 33 weeks' gestation and length of stay of more than 9 days (low acuity). More than 40% of hospitalized neonates acquired skin injury, of which the majority skin injuries were associated with medical devices required to sustain life. Increased neonatal clinician education and improved skin injury frameworks, informed by neonatal epidemiological data, are vital for the development of effective prevention strategies

Graduated colour tape measure: development and demonstration of this tool in a case series of neonatal skin injuries

This study proposed to (1) develop a metric graduated colour tool and (2) demonstrate the effectiveness of the tool for use in the assessment of neonatal skin injuries.Findings from wound literature informed the metric graduated colour tool's development. Tool development included consideration of colours, size (comparative to neonatal skin injuries), cost, materials, feasibility and suitability for the neonatal clinical setting. Assessment of the tool's applicability with clinical images was then tested using digital cameras with specific evaluation of image sharpness and colour. Further evaluation was conducted within a case series of neonatal skin injuries.The metric graduated colour tool comprised of 15 colours, measures 60 mm, displays metric dimensions, and offers a discernible reference for clinical images and injury/wound bed comparison. Images collected appeared enhanced with clear wound edges compared to previous methods. Four neonates who acquired skin injuries were included in the case series for which the tool provided reliable metric and colour comparison of epidermal stripping, extravasation, birth injury, and pressure injury. When used to compare injury assessments for series subjects measurements of both increased and decreased severity were obtained.A metric and colour tool can be used in conjunction with digital photographs to enhance objective assessment of neonatal skin injuries/wounds. The metric and colour tool provides the foundation for vital skin injury assessment and documentation essentials including injury bed colour, size and consideration of depth of damage