Comparative Efficacy, Durability and Safety of Faricimab in the Treatment of Diabetic Macular Edema: A Systematic Literature Review and Network Meta-Analysis.

INTRODUCTION: A systematic literature review (SLR) and network meta-analysis (NMA) were conducted to evaluate the comparative efficacy, durability and safety of faricimab, used in a Treat & Extend (T&E) regime with intervals up to every 16 weeks (Q16W), relative to other therapies currently in use for treatment of diabetic macular oedema (DME). Of particular interest were anti-vascular endothelial growth factor (VEGF) therapies applied in flexible dosing regimens such as Pro re nata (PRN) and T&E, which are the mainstay in clinical practice. METHODS: An SLR identifying randomised controlled trials (RCTs) published before August 2021 was conducted, followed by a Bayesian NMA comparing faricimab T&E treatment to aflibercept, ranibizumab, bevacizumab, dexamethasone and laser therapy. Outcomes included in the analysis were change in best-corrected visual acuity (BCVA), change in central subfield thickness (CST), injection frequency, ocular adverse events (AE) and all-cause discontinuation, all of which were evaluated at 12 months. Subgroup analyses including patients' naïve to anti-VEGF were conducted where feasible. RESULTS: Twenty-six studies identified in the SLR were included in the NMA. Most importantly for decision making in clinical practise, faricimab T&E was associated with a statistically greater (95% credible intervals exclude zero) and clinically meaningful decrease in retinal thickness compared to all other flexible dosing regimens (greater retinal drying by 55-125 microns). Anatomical outcomes determine treatment efficacy and retreatment of patients. The NMA also showed a statistically greater increase in mean change in BCVA for faricimab T&E vs. flexible regimens using ranibizumab and bevacizumab (increase of 4.4-4.8 letters) as well as a numerical improvement vs. aflibercept PRN (two letters, 95% credible intervals including zero). Accordingly, the injection frequency was numerically lower versus other treatments using flexible dosing regimens (decrease by 0.92-1.43 injections). The analyses also indicated that the safety profile of faricimab T&E was comparable to those of ranibizumab and aflibercept, which have well-established safety profiles, with similar results for the number of all-cause discontinuations. CONCLUSION: Faricimab provides a new treatment option in DME with dual-pathway inhibition of VEGF and angiopoeitin-2 (Ang-2). To the authors' knowledge, this is the first indirect comparison of faricimab T&E in DME. The analyses indicate that faricimab T&E is associated with superior retinal drying along with numerically fewer injections compared to all other treatments given in flexible dosing regimens. It also showed superior visual acuity outcomes compared to ranibizumab and bevacizumab.

Survival analyses from the CENTAUR trial in amyotrophic lateral sclerosis: Evaluating the impact of treatment crossover on outcomes.

INTRODUCTION/AIMS: Trials incorporating placebo-to-active treatment crossover are encouraged in fatal conditions like amyotrophic lateral sclerosis (ALS) but may underestimate active treatment survival benefit. Here, we apply methods for modeling survival without crossover, including the rank-preserving structural failure time model (RPSFTM), to data from the CENTAUR trial of sodium phenylbutyrate and taurursodiol (PB and TURSO) in ALS incorporating both randomized placebo-controlled and open-label extension (OLE) phases. METHODS: Intent-to-treat (ITT) and RPSFTM survival analyses were performed with final data at a July 2020 cutoff date. Analyses of subgroups based on randomized treatment and OLE phase participation were also performed. RESULTS: Hazard ratios (95% confidence intervals) of death for PB and TURSO versus participants initially on placebo were 0.57 (0.35-0.92) on ITT analysis and 0.39 (0.17-0.88) in the primary on-treatment RPSFTM analysis (p = .023). Median ITT survival duration for PB and TURSO (25.8 mo) was 6.9 mo longer than placebo (18.9 mo) on ITT analysis and 10.6 mo longer than the median RPSFTM-adjusted survival duration for placebo (15.2 mo). Median survival duration was 18.8 mo longer in the PB and TURSO-randomized subgroup who continued into the OLE phase versus the placebo-randomized subgroup who did not continue into the OLE phase (p < .0001), although OLE phase selection bias may have potentially confounded these results. DISCUSSION: Similar to the prespecified ITT analysis, post hoc analyses adjusting for treatment crossover in CENTAUR showed a significant survival benefit for PB and TURSO. Such methods may provide clinical context for observed survival outcomes in future ALS crossover trials.

The ultra-structural, metabolomic and metagenomic characterisation of the sudanese smokeless tobacco 'Toombak'.

Toombak is a smokeless tobacco produced from the Nicotiana rustica tobacco plant from Sudan. Pre-prepared and ready to buy Toombak samples were analysed using mass spectrometry (heavy metals), gas and liquid chromatography (metabolomics), 16S rRNA metagenomic sequencing (microbiome) and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and pH analysis. Chromium, cobalt, and copper were high in the pre-prepared form of Toombak while iron, tobacco specific nitrosamines (TSNAs), formaldehyde and acetaldehyde were high in both types. Firmicutes and Actinobacteria dominated Toombak. Samples of ready to buy Toombak showed inter-variational differences depending on place of purchase. We found Virgibacillus were increased in the pre-prepared form while Corynebacterium casei, Atopococus tabaci, Atopostipes suicloacalis, Oceanobacillus chironomi and Staphylococcus gallinarum were the most abundant species in the ready to buy forms. PICRUSt analysis highlighted increased activity of metal transport systems in the ready to buy samples as well as an antibiotic transport system. SEM-EDX highlighted large non-homogenous, irregular particles with increased sodium, while pH of samples was in the alkaline range. The final composition of Toombak is affected by its method of preparation and the end product has the potential to impart many negative consequences on the health of its users. TSNA levels observed in Toombak were some of the highest in the world while the micro-environment of Toombak supports a distinct microbiota profile.

British Association of Critical Care Nurses: Evidence-based consensus paper for oral care within adult critical care units.

BACKGROUND: Patients who are critically ill are at increased risk of hospital acquired pneumonia and ventilator associated pneumonia. Effective evidence based oral care may reduce the incidence of such iatrogenic infection. AIM: To provide an evidence-based British Association of Critical Care Nurses endorsed consensus paper for best practice relating to implementing oral care, with the intention of promoting patient comfort and reducing hospital acquired pneumonia and ventilator associated pneumonia in critically ill patients. DESIGN: A nominal group technique was adopted. A consensus committee of adult critical care nursing experts from the United Kingdom met in 2018 to evaluate and review the literature relating to oral care, its application in reducing pneumonia in critically ill adults and to make recommendations for practice. An elected national board member for the British Association of Critical Care Nurses chaired the round table discussion. METHODS: The committee focused on 5 aspects of oral care practice relating to critically ill adult patients. The evidence was evaluated for each practice within the context of reducing pneumonia in the mechanically ventilated patient or pneumonia in the non-ventilated patient. The five practices included the frequency for oral care; tools for oral care; oral care technique; solutions used and oral care in the non-ventilated patient who is critically ill and is at risk of aspiration. The group searched the best available evidence and evaluated this using the Grading of Recommendations Assessment, Development, and Evaluation system to assess the quality of evidence from high to very low, and to formulate recommendations as strong, moderate, weak, or best practice consensus statement when applicable. RESULTS: The consensus group generated recommendations, delineating an approach to best practice for oral care in critically ill adult patients. Recommendations included guidance for frequency and procedure for oral assessment, toothbrushing, and moisturising the mouth. Evidence on the use of chlorhexidine is not consistent and caution is advised with its routine use. CONCLUSION: Oral care is an important part of the care of critically ill patients, both ventilated and non-ventilated. An effective oral care programme reduces the incidence of pneumonia and promotes patient comfort. RELEVANCE TO CLINICAL PRACTICE: Effective oral care is integral to safe patient care in critical care.

Dietary Patterns Are Associated with Serum Metabolite Patterns and Their Association Is Influenced by Gut Bacteria among Older German Adults.

BACKGROUND: Although dietary intakes and dietary intake patterns (DPs) have been associated with single metabolites, it is unclear whether DPs are also reflected in specific metabolite patterns (MPs). Moreover, the influence of groups of gut bacteria on the relationship between DPs and MPs is underexplored. OBJECTIVES: We aimed to investigate the association of DPs and serum MPs and also the modifying effect of the gut bacteria compositional patterns (BCPs). METHODS: This is a cross-sectional investigation among 225 individuals (median age: 63 y; 53% women) from the European Prospective Investigation into Cancer and Nutrition study. Dietary intakes were assessed by three 24-h dietary recalls, gut bacteria composition was quantified by 16S rRNA gene sequencing, and the serum metabolome was profiled by an untargeted approach. We identified DPs and BCPs by the treelet transform analysis. We modeled associations between DPs and 8 previously published MPs and the modifying effect of BCPs by fitting generalized linear models using DataSHIELD R. RESULTS: We identified 5 DPs and 7 BCPs. The "bread, margarine, and processed meat" and "fruiting vegetables and vegetable oils" DPs were positively associated with the "amino acids" (ß = 0.35; 95% CI: 0.02, 0.69; P = 0.03) and "fatty acids" MPs (ß = 0.45; 95% CI: 0.16, 0.74; P = 0.01), respectively. The "tea and miscellaneous" was inversely associated with the "amino acids" (ß = -0.28; 95% CI: -0.52, -0.05; P = 0.02) and "amino acid derivatives" MPs (ß = -0.21; 95% CI: -0.39, -0.02; P = 0.03). One BCP negatively modified the association between the "bread, margarine, and processed meat" DP and the "amino acids" MP (P-interaction = 0.01). CONCLUSIONS: In older German adults, DPs are reflected in MPs, and the gut bacteria attenuate 1 DP-MP association. These MPs should be explored as biomarkers of these jointly consumed foods while taking into account a potentially modifying role of the gut bacteria.

"Cheese Wire" Fenestration of Dissection Intimal Flap to Facilitate Thoracic Endovascular Aortic Repair in Chronic Dissection.

Thoracic endovascular aortic repair (TEVAR) for aneurysmal chronic dissection is often complicated by retrograde filling of the false lumen and dissected distal landing zone. A "cheese wire"-style fenestration of the dissection intimal flap can create a landing zone facilitating TEVAR. This technique successfully aided TEVAR in 3 patients with an average age of 57.3 years. Complications included type III endoleak requiring relining and renal artery occlusion requiring stent placement. Average duration of clinical follow-up was 19 ± 4 months. Imaging follow-up was 8 ± 10 months. All patients have survived for more than 1 year without aneurysm enlargement.

Utility of High-Sensitivity and Conventional Troponin in Patients Undergoing Transcatheter Aortic Valve Replacement: Incremental Prognostic Value to B-type Natriuretic Peptide.

High-sensitivity Troponin (hs-Tn) has emerged as a useful marker for patients with myocardial injury or heart failure. However, few studies have compared intermediate and hs-Tn in patients undergoing transcatheter aortic valve replacement (TAVR). Moreover, there remains uncertainty of which thresholds are the most useful for discriminating ventricular dysfunction or outcome. In this study we prospectively enrolled 105 patients with severe aortic stenosis (AS) who underwent TAVR as well as blood sampling for high-sensitivity (hs-TnI) and conventional troponin I (EXL-LOCI and RXL) assessment. Patients underwent comprehensive pre-procedure echocardiography. Ventricular dysfunction was defined using left ventricular mass index (LVMI), LV global longitudinal strain (LVGLS) and LV end-diastolic pressure. The mean age was 84.0 ± 8.7 years old and 60% were male sex with mean transaortic pressure gradient of 50.1 ± 16.0 mmHg and AVA of 0.63 ± 0.19 cm2. When using a threshold of 6 ng/L, 77% had positive hs-TnI while 27% had positive hs-TnI using recommended thresholds (16 ng/L for female and 34 ng/L for male). Troponin levels were higher in the presence of abnormal LV phenotypes. The strongest correlate of troponin was LVMI. During median follow-up of 375 days, 21 patients (20%) died. Lower threshold of hs-TnI and EXL-TnI was more discriminatory for overall mortality (Log-rank P = 0.03 for both), while higher threshold of hs-TnI (p = 0.75) and RXL-TnI were not (p = 0.30). Combining hs-TnI and BNP improved to predict long-term outcome (p = 0.004). In conclusion, hs-TnI levels correlated with the degree of LV dysfunction phenotypes. Furthermore, applying a lower threshold for hs-TnI performed better for outcome prediction than a recommended threshold in patients undergoing TAVR. Combining hs-TnI with BNP helped better risk stratification.

Comparative Efficacy of Second- and Subsequent-line Treatments for Metastatic NSCLC: A Fractional Polynomials Network Meta-analysis of Cancer Immunotherapies.

BACKGROUND: Extended onset of treatment effect and longer-term survival with anti-programmed death-ligand 1 (PD-L1)/programmed cell death protein 1 (PD-1) immunotherapies, atezolizumab, nivolumab, and pembrolizumab, have changed the landscape of second- or subsequent-line (2L+) treatments for adults with non-small-cell lung cancer (NSCLC). This systematic literature review included phase I to IV randomized, controlled trials of 2L+ NSCLC therapies from MEDLINE, Embase, and secondary sources. MATERIALS AND METHODS: Studies of treatments approved in the European Union or United States had to be in English with ≥ 10 patients per arm. A fractional polynomials network meta-analysis (NMA) was conducted because traditional NMA of hazard ratios does not account for delayed onset of clinical effect or long-term survival observed in PD-L1/PD-1 inhibitor trials. Adjusted analyses accounted for treatment switching in the atezolizumab OAK trial. Expected survival time reflected area under the curve over the time horizon. Expected overall survival (OS) was ranked by median ranking with 95% credible intervals and by surface under the cumulative ranking curve. Of 25,115 screened records, 28 studies were included in the quantitative analyses of OS and progression-free survival. RESULTS: PD-L1/PD-1 inhibitors had comparable expected 5-year OS; all performed better than other treatment options. In unadjusted analyses, surface under the cumulative ranking curve ranked nivolumab first (87.9%), followed by atezolizumab (85.8%) and pembrolizumab (82.8%). Analyses adjusted for patients switching from docetaxel to immunotherapy ranked atezolizumab first (89.6%), followed by nivolumab (86.5%) and pembrolizumab (81.9%). CONCLUSION: This NMA applied an appropriate approach for indirect comparisons, including cancer immunotherapies, and supported robustness of PD-L1/PD-1 immunotherapies for 2L+ treatment of NSCLC.

Perinatal factors affect the gut microbiota up to four years after birth.

Perinatal factors impact gut microbiota development in early life, however, little is known on the effects of these factors on microbes in later life. Here we sequence DNA from faecal samples of children over the first four years and reveal a perpetual evolution of the gut microbiota during this period. The significant impact of gestational age at birth and delivery mode on gut microbiota progression is evident in the first four years of life, while no measurable effects of antibiotics are found in the first year. Microbiota profiles are also characteristic in children dependant on gestational age and maturity. Full term delivery is characterised by Bacteroides (year one), Parabacteroides (year two) and Christensenellaceae (year four). Preterm delivery is characterised by Lactobacillus (year one), Streptococcus (year two) and Carnobacterium (year four). This study reveals that the gut retains distinct microbial profiles of perinatal factors up to four years of age.

Dietary fat, the gut microbiota, and metabolic health - A systematic review conducted within the MyNewGut project.

BACKGROUND AND AIMS: Studies indicate that dietary fat quantity and quality influence the gut microbiota composition which may as a consequence impact metabolic health. This systematic review aims to summarize the results of available studies in humans on dietary fat intake (quantity and quality), the intestinal microbiota composition and related cardiometabolic health outcomes. METHODS: We performed a systematic review (CRD42018088685) following PRISMA guidelines and searched for literature in Medline, EMBASE, and Cochrane databases. RESULTS: From 796 records, 765 records were excluded based on title or abstract. After screening of 31 full-text articles six randomized controlled trials (RCT) and nine cross-sectional observational studies were included. Our results of interventional trials do not suggest strong effects of different amounts and types of dietary fat on the intestinal microbiota composition or on metabolic health outcomes while observational studies indicate associations with the microbiota and health outcomes. High intake of fat and saturated fatty acids (SFA) may negatively affect microbiota richness and diversity and diets high in monounsaturated fatty acids (MUFA) may decrease total bacterial numbers whereas dietary polyunsaturated fatty acids (PUFA) had no effect on richness and diversity. CONCLUSIONS: High fat and high SFA diets can exert unfavorable effects on the gut microbiota and are associated with an unhealthy metabolic state. Also high MUFA diets may negatively affect gut microbiota whereas PUFA do not seem to negatively affect the gut microbiota or metabolic health outcomes. However, data are not consistent and most RCT and observational studies showed risks of bias.

Dose-interval study of a dual probiotic in preterm infants.

OBJECTIVE: The objective of this study was to investigate the appropriate dosing interval of a probiotic (Infloran) given daily, biweekly and weekly in preterm infants <32 weeks' gestation. METHODS: There were 8 infants in the daily group, 8 infants in the biweekly group and 10 infants in the weekly group, all born between 25 and 32 weeks' gestation. The control group consisted of 12 preterm infants who did not receive the probiotic. Infloran (250 mg/capsule), containing Bifidobacterium bifidum (1×109 colony-forming unit (CFU)) and Lactobacillus acidophilus (1×109 CFU), was administered in 2.5 mL of breast milk per kilogram weight of the infant (2×109 CFU of bacteria in total), until 34 weeks postmenstrual age (PMA). Stool samples were collected at 31, 34, 41 and 44 weeks PMA and frozen at -20°C. RESULTS: After administration of the probiotic at 31 weeks PMA, Bifidobacterium were significantly higher in the daily group (45%) in comparison with the biweekly (17%) and weekly (9%) groups. At 34 weeks PMA, Bifidobacterium were significantly higher again in the daily (60%) group in comparison with the biweekly (21%), weekly (23%) and control (15%) groups. At 41 weeks PMA a decrease in the relative abundances of Streptococcaceae and Enterococcaceae was found in all three probiotic groups, and by 44 weeks PMA significantly higher levels of Lactobacillus were found in the biweekly group (16.5%) in comparison with the weekly group (2.1%). CONCLUSION: Our results indicate that a daily dose of Infloran is a suitable dosage for preterm infants in the neonatal intensive care unit, with significantly higher levels of Bifidobacterium found in the daily probiotic group up to 44 weeks PMA.

Kissing Stents for Superior Vena Cava Syndrome Due to Mediastinal Fibrosis.

PURPOSE: To report the endovascular reconstruction of the superior vena cava (SVC), innominate and internal jugular veins following stenosis due to mediastinal fibrosis. CASE REPORT: A 36-year-old female with mediastinal fibrosis was referred for symptomatic SVC syndrome (SVCS). A covered stent was inserted in the SVC with 2 kissing stents in the innominate and jugular veins via anterograde right femoral vein access with sandwich technique. She exhibited near-immediate relief of debilitating symptoms. Computed tomographic scan demonstrated patent vessels at 1 year. CONCLUSIONS: Extensive endovascular venous reconstruction is an effective treatment for SVCS due to mediastinal fibrosis.

A simple method for combining binomial counts or proportions with hazard ratios for evidence synthesis of time-to-event data.

In studies with time-to-event data, outcomes may be reported as hazard ratios (HR) or binomial counts/proportions at a specific time point. If the intent is to synthesise evidence by performing a meta-analysis or network meta-analysis (NMA) using the HR as the measure of treatment effect, studies that only report binomial data cannot be included in the network. Methods for converting binomial data to HRs were investigated, so that studies reporting binomial data only could be included in a network of HR data. Estimating the log HR is relatively straightforward under the assumptions of proportional hazards and minimal censoring at the binomial data time point. Estimating the standard error of the log HR is harder, but a simple method based on using a Taylor series expansion to approximate the variance is proposed. Thus, we have 2 easy-to-calculate equations for the log HR and variance. The performance of the method was assessed using simulations and data from a NMA of multiple sclerosis treatments. In the simulation, our binomial method produced very similar HRs to those from survival analysis when censoring rates were low, and also when censoring rates were high but the event rate was low. In all situations, it outperformed using relative risk to approximate the HR. In the NMA, results were consistent between reported HRs and HRs derived from binomial data for studies that reported both types of data. This method may be useful for easily incorporating trials reporting binomial data into an evidence synthesis of HR data, under certain assumptions.

Tryptophan metabolic profile in term and preterm breast milk: implications for health.

Breast milk is the only source of the essential amino acid tryptophan (TRP) in breast-fed infants. Low levels of TRP could have implications for infant neurodevelopment. The objectives of the present study were to compare the relationship of TRP and its neuroactive pathway metabolites kynurenine (Kyn) and kynurenic acid (KynA) in preterm and term expressed breast milk (EBM) in the first 14 d following birth, and the relationship of TRP metabolism to maternal stress and immune status. A total of twenty-four mothers were recruited from Cork University Maternity Hospital: twelve term (>38 weeks) and twelve preterm (<35 weeks). EBM samples were collected on days 7 and 14. Free TRP, Kyn and KynA were measured using HPLC, total TRP using MS, cytokines using the Meso Scale Discovery (MSD) assay system, and cortisol using a cortisol ELISA kit. Although total TRP was higher in preterm EBM in comparison with term EBM (P < 0·05), free TRP levels were lower (P < 0·05). Kyn, KynA and the Kyn:TRP ratio increased significantly in term EBM from day 7 to day 14 (P < 0·05), but not in preterm EBM. TNF-α, IL-6 and IL-8 were higher in day 7 preterm and term EBM in comparison with day 14. There were no significant differences between term and preterm EBM cortisol levels. Increased availability of total TRP, lower levels of free TRP and alterations in the temporal dynamics of TRP metabolism in preterm compared with term EBM, coupled with higher EBM inflammatory markers on day 7, may have implications for the neurological development of exclusively breast-fed preterm infants.

The viability of probiotics in water, breast milk, and infant formula.

The aim of this study was to determine bacteriological stability of a probiotic mixture dispersed in various diluents. The commercially available probiotic (Infloran®), containing Bifidobacterium bifidum (109 CFU/250 mg tablet) and Lactobacillus acidophilus (109 CFU/250 mg tablet), was dispersed within expressed breast milk, sterile water, and infant formula and examined at temperatures of 4 and 21 °C. When stored at 4 °C, significant decreases (P < 0.05) in the level of L. acidophilus and B. bifidum were observed in expressed breast milk and sterile water after a 6-h period. However, when stored in infant formula, both strains remained stable over a 12-h period. When stored at 21 °C, a significant decrease (P < 0.05) was observed in the level of L. acidophilus in sterile water, expressed breast milk and infant formula throughout a 12-h period. However, no significant decrease was observed overtime in B. bifidum in all three diluents at this temperature. CONCLUSION: Our findings suggest that, when stored at 4 °C, this probiotic product can remain at a stable condition for 6 h in sterile water and infant formula; however, the viability of the probiotic decreases significantly after this period of time. Administration of this probiotic in sterile water can be an acceptable alternative to dispersion and administration in expressed breast milk. What is Known: • Administration of probiotics containing lactobacilli and bifidobacteria has become more widespread in neonatology, mainly as prophylaxis for the prevention of necrotising entercolitis in preterm infants. • Probiotic reconstitution, from its powder base, is not standardized and various diluents, including sterile water, breast milk, and infant formula, have been used. What is New: • When stored at 4 °C, a probiotic containing lactobacilli and bifidobacteria remains at a stable microbological condition for up to 6 h in sterile water. • Administration of this probiotic dispersed in sterile water, followed by an EBM feed, can be an acceptable alternative to dispersion and administration in EBM.

Microbial Therapeutics Designed for Infant Health.

Acknowledgment of the gut microbiome as a vital asset to health has led to multiple studies attempting to elucidate its mechanisms of action. During the first year of life, many factors can cause fluctuation in the developing gut microbiome. Host genetics, maternal health status, mode of delivery, gestational age, feeding regime, and perinatal antibiotic usage, are known factors which can influence the development of the infant gut microbiome. Thus, the microbiome of vaginally born, exclusively breastfed infants at term, with no previous exposure to antibiotics, either directly or indirectly from the mother, is to be considered the "gold standard." Moreover, the use of prebiotics as an aid for the development of a healthy gut microbiome is equally as important in maintaining gut homeostasis. Breastmilk, a natural prebiotic source, provides optimal active ingredients for the growth of beneficial microbial species. However, early life disorders such as necrotising enterocolitis, childhood obesity, and even autism have been associated with an altered/disturbed gut microbiome. Subsequently, microbial therapies have been introduced, in addition to suitable prebiotic ingredients, which when administered, may aid in the prevention of a microbial disturbance in the gastrointestinal tract. The aim of this mini-review is to highlight the beneficial effects of different probiotic and prebiotic treatments in early life, with particular emphasis on the different conditions which negatively impact microbial colonisation at birth.