Timing of antimicrobial prophylaxis for cesarean section is critical for gut microbiome development in term born infants

Exposure to prescribed medication in early life and impacts on gut microbiota and disease development

The gut microbiota during early life plays a crucial role in infant development. This microbial-host interaction is also essential for metabolism, immunity, and overall human health in later life. Early-life pharmaceutical exposure, mainly referring to exposure during pregnancy, childbirth, and infancy, may change the structure and function of gut microbiota and affect later human health. In this Review, we describe how healthy gut microbiota is established in early life. We summarise the commonly prescribed medications during early life, including antibiotics, acid suppressant medications and other medications such as antidepressants, analgesics and steroid hormones, and discuss how these medication-induced changes in gut microbiota are involved in the pathological process of diseases, including infections, inflammatory bowel disease, metabolic diseases, allergic diseases and neurodevelopmental disorders. Finally, we review some critical methods such as dietary therapy, probiotics, prebiotics, faecal microbiota transplantation, genetically engineered phages, and vagus nerve stimulation in early life, aiming to provide a new strategy for the prevention of adverse health outcomes caused by prescribed medications exposure in early life.

Investigating prenatal and perinatal factors on meconium microbiota: a systematic review and cohort study

BACKGROUND

The first-pass meconium has been suggested as a proxy for the fetal gut microbiota because it is formed in utero. This systematic review and cohort study investigated how pre- and perinatal factors influence the composition of the meconium microbiota.

METHODS

We performed the systematic review using Covidence by searching PubMed, Scopus, and Web of Science databases with the search terms "meconium microbiome" and "meconium microbiota". In the cohort study, we performed 16 S rRNA gene sequencing on 393 meconium samples and analyzed the sequencing data using QIIME2.

RESULTS

Our systematic review identified 69 studies exploring prenatal factors, immediate perinatal factors, and microbial composition in relation to subsequent health of infants but gave only limited comparative evidence regarding factors related to the composition of the meconium microbiota. The cohort study pointed to a low-biomass microbiota consisting of the phyla Firmicutes, Proteobacteria and Actinobacteriota and the genera Staphylococcus, Escherichia-Shigella and Lactobacillus, and indicated that immediate perinatal factors affected the composition of the meconium microbiota more than did prenatal factors.

CONCLUSIONS

This finding supports the idea that the meconium microbiota mostly starts developing during delivery.

IMPACT

It is unclear when the first-pass meconium microbiota develops, and what are the sources of the colonization. In this systematic review, we found 69 studies exploring prenatal factors, immediate perinatal factors, and microbial composition relative to subsequent health of infants, but there was no consensus on the factors affecting the meconium microbiota development. In this cohort study, immediate perinatal factors markedly affected the meconium microbiota development while prenatal factors had little effect on it. As the meconium microbiota composition was influenced by immediate perinatal factors, the present study supports the idea that the initial gut microbiota develops mainly during delivery.

Signalling cognition: the gut microbiota and hypothalamic-pituitary-adrenal axis

Cognitive function in humans depends on the complex and interplay between multiple body systems, including the hypothalamic-pituitary-adrenal (HPA) axis. The gut microbiota, which vastly outnumbers human cells and has a genetic potential that exceeds that of the human genome, plays a crucial role in this interplay. The microbiota-gut-brain (MGB) axis is a bidirectional signalling pathway that operates through neural, endocrine, immune, and metabolic pathways. One of the major neuroendocrine systems responding to stress is the HPA axis which produces glucocorticoids such as cortisol in humans and corticosterone in rodents. Appropriate concentrations of cortisol are essential for normal neurodevelopment and function, as well as cognitive processes such as learning and memory, and studies have shown that microbes modulate the HPA axis throughout life. Stress can significantly impact the MGB axis via the HPA axis and other pathways. Animal research has advanced our understanding of these mechanisms and pathways, leading to a paradigm shift in conceptual thinking about the influence of the microbiota on human health and disease. Preclinical and human trials are currently underway to determine how these animal models translate to humans. In this review article, we summarize the current knowledge of the relationship between the gut microbiota, HPA axis, and cognition, and provide an overview of the main findings and conclusions in this broad field.

First-Day-of-Life Rectal Swabs Fail To Represent Meconial Microbiota Composition and Underestimate the Presence of Antibiotic Resistance Genes

The human gut microbiome plays a vital role in health and disease. In particular, the first days of life provide a unique window of opportunity for development and establishment of microbial community. Currently, stool samples are known to be the most widely used sampling approach for studying the gut microbiome. However, complicated sample acquisition at certain time points, challenges in transportation, and patient discomfort underline the need for development of alternative sampling approaches. One of the alternatives is rectal swabs, shown to be a reliable proxy for gut microbiome analysis when obtained from adults. Here, we compare the usability of rectal swabs and meconium paired samples collected from infants on the first days of life. Our results indicate that the two sampling approaches display significantly distinct patterns in microbial composition and alpha and beta diversity as well as detection of resistance genes. Moreover, the dissimilarity between the two collection methods was greater than the interindividual variation. Therefore, we conclude that rectal swabs are not a reliable proxy compared to stool samples for gut microbiome analysis when collected on the first days of a newborn's life. IMPORTANCE Currently, there are numerous suggestions on how to ease the notoriously complex and error-prone methodological setups to study the gut microbiota of newborns during the first days of life. Especially, meconium samples are regularly failing to yield meaningful data output and therefore have been suggested to be replaced by rectal swabs as done in adults as well. We find this development toward a simplified method to be producing dramatically erroneous results, skewing data interpretation away from the real aspects to be considered for neonatal health during the first days of life. We have put together our knowledge on this critical aspect with careful consideration and identified the failure of rectal swabs to be a replacement for sampling of meconium in term-born newborns.

Hearing rehabilitation and microbial shift after middle ear surgery with Vibrant Soundbridge in patients with chronic otitis media

INTRODUCTION

Patients with otitis media (OM) encounter significant functional hearing impairment with conductive, or a combined hearing loss and long-term sequelae involving impaired speech/language development in children, reduced academic achievement and irreversible disorders of middle and inner ear requiring a long time therapy and/or multiple surgeries. In its persistent chronic form, Otitis media (COM) can often only be treated by undergoing ear surgery for hearing restoration. The persistent inflammatory reaction plays a major role, often caused by multi-resistant pathogens in the ear. Herein, we present outcomes of patients implanted with currently the only FDA approved active Middle Ear Implant Vibrant Soundbridge (VSB), suffering from persistent COM.

METHODS

The study enrolled 42 patients, treated by performing middle ear (ME) surgery to different extents and implanted with the VSB to various structures in the ME. Included were 17 children and 25 adults that had recurrent and/or persisting OM and significant hearing loss. Preoperative and postoperative patients' audiometric data were evaluated and the benefit with VSB assessed using the Glasgow Benefit Inventory for adults and pediatric cohorts. The microbial spectrum of pathogens was assessed before and after surgery, exploring the colonization of the otopathogens, as well as the intestinal microbiome from individually burdened patients.

RESULTS

The mean functional gain is 29.7 dB HL (range from 10 to 56.2 dB HL) with a significant improvement in speech intelligibility in quiet. Following VSB implantation, no significant differences in coupling were observed at low complication rates. Postoperatively patients showed significantly increased benefit with VSB compared to the untreated situation, including less otorrhea, pain, medical visits, and medication intake, with no recurrent OM and significant bacterial shift in otopathogens. The analysis of the intestinal microbiome displayed a high abundance of bacterial strains that might be linked to chronic and persistent inflammation.

CONCLUSIONS

Functional ear surgery including rehabilitation with a VSB in patients suffering from COM present to be safe and effective. The successful acceptance accompanied by the improved audiological performance resulted in significant benefit with VSB, with a shift in the ear pathogens and altered microbiome and thus is a great opportunity to be treated.

Antibiotic Use During Pregnancy and Childbirth: Prospective Observational Study on Prevalence, Indications, and Prescribing Patterns in a German Tertiary Center

Introduction Antibiotics are powerful drugs to prevent and treat perinatal infections. Overuse of antibiotics leads to antibiotic resistance, has potential side effects and influences the maternal and neonatal microbiome.

Patients and Methods We performed a prospective observational study on the prevalence, indications, and prescribing patterns of antibiotics during pregnancy and childbirth. We included women who had given birth after 23+0 weeks of gestation at a single tertiary center in Germany from January 2020 to March 2021. Descriptive statistics and binomial regression were performed to analyze the factors influencing the prescription of antibiotics.

Results We included 522 postpartum women into our study. 337 (64.6%) were exposed to antibiotics during pregnancy and/or childbirth. 115 women received antibiotics during pregnancy, 291 during birth. Most antibiotics during pregnancy were prescribed for urinary tract infections (UTIs) (56.0%). Most prescriptions were issued by obstetrics and gynecology physicians (65.8%), followed by hospitals (16.7%) and family medicine physicians (8.8%). Most antibiotics during childbirth were given for a cesarean section (64.3%), followed by preterm rupture of membranes (41.2%). 95.3% of women who had a preterm birth were exposed to antibiotics. In logistic regression models, lower gestational age at birth, higher maternal body-mass-index and smoking were independently associated with antibiotic use during pregnancy and childbirth.

Conclusion We found a high rate of antibiotic exposure during pregnancy and childbirth. Our results imply an urgent need for antibiotic stewardship programs in perinatal medicine as well as further research on the effects of perinatal antibiotic exposure on microbiome development and childhood health.

Application of a Physiologically Based Pharmacokinetic Model to Predict Cefazolin and Cefuroxime Disposition in Obese Pregnant Women Undergoing Caesarean Section

Intravenous (IV) cefuroxime and cefazolin are used prophylactically in caesarean sections (CS). Currently, there are concerns regarding sub-optimal dosing in obese pregnant women compared to lean pregnant women prior to CS. The current study used a physiologically based pharmacokinetic (PBPK) approach to predict cefazolin and cefuroxime pharmacokinetics in obese pregnant women at the time of CS as well as the duration that these drug concentrations remain above a target concentration (2, 4 or 8 µg/mL or µg/g) in plasma or adipose tissue. Cefazolin and cefuroxime PBPK models were first built using clinical data in lean and in obese non–pregnant populations. Models were then used to predict cefazolin and cefuroxime pharmacokinetics data in lean and obese pregnant populations. Both cefazolin and cefuroxime models sufficiently described their total and free levels in the plasma and in the adipose interstitial fluid (ISF) in non–pregnant and pregnant populations. The obese pregnant cefazolin model predicted adipose exposure adequately at different reference time points and indicated that an IV dose of 2000 mg can maintain unbound plasma and adipose ISF concentration above 8 µg/mL for 3.5 h post dose. Predictions indicated that an IV 1500 mg cefuroxime dose can achieve unbound plasma and unbound ISF cefuroxime concentration of ≥8 µg/mL up to 2 h post dose in obese pregnant women. Re-dosing should be considered if CS was not completed within 2 h post cefuroxime administration for both lean or obese pregnant if cefuroxime concentrations of ≥8 µg/mL is required. A clinical study to measure cefuroxime adipose concentration in pregnant and obese pregnant women is warranted.

Infant gut microbiota restoration: state of the art

The gut microbiota has a central role in the programming of the host's metabolism and immune function, with both immediate and long-term health consequences. Recent years have witnessed an accumulation of understanding of the process of the colonization and development of the gut microbiota in infants. The natural gut microbiota colonization during birth is frequently disrupted due to C-section birth or intrapartum or postpartum antibiotic exposure, and consequently aberrant gut microbiota development is common. On a positive note, research has shown that restoration of normal gut microbiota development is feasible. We discuss here the current understanding of the infant microbiota, provide an overview of the sources of disturbances, and critically evaluate the evidence on early life gut microbiota restoration for improved health outcomes by analyzing published data from infant gut microbiota restoration studies.