Dynamics of the bacterial gut microbiota in preterm and term infants after intravenous amoxicillin/ceftazidime treatment

Effect of β-lactam antibiotics on the gut microbiota of term neonates

β-Lactam antibiotics are a class of antibiotics commonly used to treat bacterial infections. However, the effects of β-lactam antibiotics on term neonatal intestinal flora have not been fully elucidated. Hospitalized full-term newborns receiving β-lactam antibiotics formed the antibiotic group (n = 67), while those without antibiotic treatment comprised the non-antibiotic group (n = 47). A healthy group included healthy full-term newborns (n = 16). Stool samples were collected for 16 S rDNA sequencing to analyze gut microbiota variations. Further investigation was carried out within the β-lactam antibiotic group, exploring the effects of antibiotic use on the newborns' gut microbiota in relation to the duration and type of antibiotic administration, delivery method, and feeding practices. The antibiotic group exhibited significant difference of microbial community composition compared to the other groups. Genera like Klebsiella, Enterococcus, Streptococcus, Alistipes, and Aeromonas were enriched, while Escherichia-Shigella, Clostridium sensu stricto 1, Bifidobacterium, and Parabacteroides were reduced. Klebsiella negatively correlated with Escherichia-Shigella, positively with Enterobacter, while Escherichia-Shigella negatively correlated with Enterococcus and Streptococcus. Regardless of neonatal age, β-lactam antibiotics induced an elevated abundance of Klebsiella and Enterococcus. The impact on gut microbiota varied with the duration and type of antibiotic (cefotaxime or ampicillin/sulbactam). Compared to vaginal delivery, cesarean delivery after β-lactam treatment heightened the abundance of Klebsiella, Enterobacteriaceae_Unclassified, Lactobacillales_Unclassified, and Pectobacterium. Feeding patterns minimally influenced β-lactam-induced alterations. In conclusion, β-lactam antibiotic treatment for neonatal pneumonia and sepsis markedly disrupted intestinal microbiota, favoring Klebsiella, Enterococcus, Streptococcus, Alistipes, and Aeromonas. The impact of β-lactam varied by duration, type, and delivery method, emphasizing heightened disruptions post-cesarean delivery.

Alterations in gut microbiota and inflammatory cytokines after administration of antibiotics in mice

Antibiotics are widely used to treat bacterial infection and reduce the mortality rate, while antibiotic overuse can cause gut microbiota dysbiosis. The impact of antibiotics on gut microbiota is not fully understood. In our study, four commonly used antibiotics (ceftazidime, cefoperazone-sulbactam, imipenem-cilastatin, and moxifloxacin) were given subcutaneously to mice, and their impacts on the gut microbiota composition and serum cytokine levels were evaluated through 16S rRNA analysis and a multiplex immunoassay. Antibiotic treatment markedly reduced gut microbiota diversity and changed gut microbiota composition. Antibiotic treatment significantly increased and decreased the abundance of Firmicutes and Bacteroidota, respectively. The antibiotic treatments increased the abundance of opportunistic pathogens such as Enterococcus and decreased that of Lachnospiraceae and Muribaculaceae. For moxifloxacin, the significantly high abundance of Enterococcus and Klebsiella was observed after 14 and 21 days of treatment. However, a relatively low abundance of opportunistic pathogens was found after 14 days of imipenem-cilastatin treatment. Additionally, the serum levels of various pro-inflammatory cytokines, such as IL-1β, IL-12 (p70), and IL-17, significantly increased after 21 days of antibiotic treatments. Overall, these results provide a guide for rational use of antibiotics in clinical settings: short-term use of moxifloxacin is recommended with regard to gut microbiota health, and the 14-day use of imipenem-cilastatin may have a less severe impact than other antibiotics.IMPORTANCEAntibiotic treatments are directly associated with changes in gut microbiota and are effective against both pathogens and beneficial bacteria. Gut microbiota dysbiosis induced by antibiotic treatment could increase the risk of some diseases. Therefore, an adequate understanding of gut microbiota changes after antibiotic use is crucial. In this study, we investigated the effects of continuous treatment with antibiotics on gut microbiota, serum cytokines, and intestinal inflammatory response. Our results suggest that short-term use of moxifloxacin is recommended, and the 14-day use of imipenem-cilastatin may have a less severe effect on gut microbiota health than cefoperazone-sulbactam. These results provide useful guidance on the rational use of antibiotics with regard to gut microbiota health.

Maternal Vertical Microbial Transmission During Skin-to-Skin Care

BACKGROUND

Skin-to-skin (STS) care may contribute to mother-to-infant vertical microbial transmission by enriching the preterm infant's microbiome.

PURPOSE

The purpose of this observational study was to define the impact of increased STS care duration on vertical microbial transmission and consequently modulate oral and intestinal microbial balance.

METHODS

Postpartum women and their preterm infants, 31 to 34 weeks' gestation (n = 25), were recruited for this study. Using 16S rRNA sequencing, we compared α- and β-diversity with the Shannon and Chao indexes and nonmetric multidimensional scaling, respectively, and relative abundance of microbial communities, which refers to the percentage of specific organisms in a community, from mother's chest skin, preterm infant's oral cavity, and preterm infant's stool samples. Effects of STS care on vertical transmission were determined by comparing oral and stool microbial population of preterm infants who received low exposure (<40 minutes) with that of preterm infants who received high exposure (>60 minutes).

RESULTS

Microbial composition, diversity, and relative abundance were different across the 3 sites. Oral microbial richness was less and stool richness was greater among the preterm infants in the high STS care group. Oral and intestinal microbial diversity and composition were different between the groups, with the relative abundance of Gemella and Aggregatibacter genera and Lachnospiraceae family significantly greater in the stool of the high STS care group.

IMPLICATIONS FOR PRACTICE

Results suggest that STS care may be an effective method to enhance microbial communities among preterm infants.

The metagenomic and metabolomic profile of the gut microbes in Chinese full-term and late preterm infants treated with Clostridium butyricum

The present study investigated the composition, abundance, and diversity of gut microbes in full-term and late-preterm infants from a medical center in eastern China. A total of 144 genomes of stool samples were captured for 16S rRNA metagenomic analyses. A high abundance of commensal intestinal bacteria was detected in these samples such as Phocaeicola vulgatus, Escherichia coli, and Faecalibacterium prausnitzii, indicating a relatively consistent diversity of gut microbes in the present full-term infants aged 38-40 weeks. However, late preterm infants (n = 50) with mandatory antimicrobials feeding exhibited lower diversity but a higher composition of opportunistic pathogens such as Enterococcus species. Centralized on the situation, we explored the regulatory effect of Clostridium butyricum as probiotics on these late preterm infants. The consumption of C. butyricum did not restore the composition of gut microbes altered by antimicrobials to normal levels, although several opportunistic pathogens decreased significantly after probiotic therapy including Staphylococcus aureus, Sphingomonas echinoides, and Pseudomonas putida. We also compared the effects of day-fed versus night-fed probiotics. Intriguingly, the nighttime feeding showed a higher proportion of C. butyricum compared with probiotic day-feeding. Finally, fecal metabolome and metabolites were analyzed in late preterm infants with (n = 20) or without probiotic therapy (n = 20). The KEGG enrichment analysis demonstrated that vitamin digestion and absorption, synaptic vesicle cycle, and biotin metabolism were significantly increased in the probiotic-treated group, while MSEA indicated that a series of metabolism were significantly enriched in probiotic-treated infants including glycerolipid, biotin, and lysine, indicating the complex effects of probiotic therapy on glutathione metabolism and nutrients digestion and absorption in late preterm infants. Overall, this study provided metagenomic and metabolomic profile of the gut microbes in full-term newborns and late preterm infants in eastern China. Further studies are needed to support and elucidate the role of probiotic feeding in late preterm infants with mandatory antimicrobial treatment.

Long-term dysbiosis and fluctuations of gut microbiome in antibiotic treated preterm infants

Postnatal acquisition of the microbiome is critical to infant health. In preterm infants, empiric use of antibiotics is common, with significant health consequences. To understand the influence of antibiotics on acquisition of the microbiome over time, we longitudinally profiled microbial 16S rRNA in the stool of 79 preterm infants during their hospitalization in the intensive care unit and compared antibiotic treated and untreated infants. Despite similar clinical presentation, antibiotic treated infants had strong deviations in the content, diversity, and most dramatically, temporal stability of their microbiome. Dysbiosis and fluctuations of microbiome content persisted long after antibiotic exposure, up to hospital discharge. Microbiome diversity was dominated by a few common bacteria consistent among all infants. Our findings may inform clinical practice related to antibiotic use and targeted microbial interventions aimed at overcoming the adverse influence of antibiotics on the microbiome of preterm infants at specific developmental time points.

Dysbiosis in Gut Microbiota in Children Born Preterm Who Developed Autism Spectrum Disorder: A Pilot Study

The gut microbiota was reported to differ between children with autism spectrum disorder (ASD) and typically developing (TD) children, and dysbiosis of the gut microbiota in preterm infants is common. Here, we explored the characteristics of gut microbiota in children born preterm with ASD. We performed 16S rRNA gene sequencing using stool samples from ASD children born preterm and TD children born preterm. Alpha diversity was significantly greater in the ASD group. A comparison of beta diversity showed different clusters. Linear discriminant analysis effect size analysis revealed significantly more Firmicutes in the ASD group compared with the TD group. In conclusion, the gut microbiota in children born preterm differs between children with ASD and TD.

Impact of maternal factors, environmental factors, and race on necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a complex disease with a multifactorial etiology. As the leading cause of intestinal morbidity and mortality among premature infants, many resources are being dedicated to neonatal care and molecular targets in the newborn intestine. However, NEC is heavily influenced by maternal and perinatal factors as well. Given its nature, preventive approaches to NEC are more likely to improve outcomes than new treatment strategies. Therefore, this review focuses on maternal, environmental, and racial factors associated with the development of NEC, with an emphasis on those that may be modifiable to decrease the incidence of the disease.

Necrotizing Enterocolitis: The Role of Hypoxia, Gut Microbiome, and Microbial Metabolites

Necrotizing enterocolitis (NEC) is a life-threatening disease that predominantly affects very low birth weight preterm infants. Development of NEC in preterm infants is accompanied by high mortality. Surgical treatment of NEC can be complicated by short bowel syndrome, intestinal failure, parenteral nutrition-associated liver disease, and neurodevelopmental delay. Issues surrounding pathogenesis, prevention, and treatment of NEC remain unclear. This review summarizes data on prenatal risk factors for NEC, the role of pre-eclampsia, and intrauterine growth retardation in the pathogenesis of NEC. The role of hypoxia in NEC is discussed. Recent data on the role of the intestinal microbiome in the development of NEC, and features of the metabolome that can serve as potential biomarkers, are presented. The Pseudomonadota phylum is known to be associated with NEC in preterm neonates, and the role of other bacteria and their metabolites in NEC pathogenesis is also discussed. The most promising approaches for preventing and treating NEC are summarized.

Epidemiology of group B streptococcal disease in infants younger than 1 year in Japan: a nationwide surveillance study 2016-2020

We aimed to define the burden and clinical features of invasive group B streptococcus (GBS) disease in infants younger than 1 year in Japan, to explore transmission route of late-onset disease (LOD), and to identify risk factors associated with recurrent GBS disease. We conducted a retrospective, questionnaire-based nationwide surveillance study between 2016 and 2020. A total of 875 GBS cases were identified, including 186 early-onset disease, 628 LOD, and 61 ultra-late-onset disease. Case fatality rate in each age category was 6.5%, 3.0%, and 3.3%, respectively. Patients with meningitis had neurodevelopmental sequelae in 21.5% (64/297). Annual incidence in infants younger than 1 year and in LOD significantly increased from 0.28 to 0.45/1000 livebirths (p = 0.021) and from 0.19 to 0.29/1000 livebirths (p = 0.046), respectively. Maternal colonization status at the LOD diagnosis was available for 148 mothers, of whom 21/58 (36.2%) had positive rectovaginal swabs and 42/117 (36.2%) had GBS in breastmilk culture. These two sites are potentially infectious routes in LOD. The four leading disease-causing serotypes III, Ia, Ib, and V represented 95% of the available serotypes. Thirty-one recurrent cases were identified, accounting for 3.7% of total patients. A multivariate regression analysis showed that prematurity (p = 0.029) and antepartum maternal GBS colonization (p = 0.032) were significantly associated with risk for the recurrence. Our findings indicated that GBS disease burden still remains with considerable mortality and morbidity in Japan, and provided important information for developing better strategies for the prevention of GBS disease, including maternal vaccination.

The first fungi: mode of delivery determines early life fungal colonization in the intestine of preterm infants

Aim: The role of intestinal fungi in human health and disease is becoming more evident. The mycobiota composition and diversity of preterm infants is affected by interactions with bacteria and clinical variables. In this study, we aimed to characterize the composition and the diversity of the preterm infant mycobiota and the effect of clinical variables on it in the first six postnatal weeks. Methods: Preterm infants (n = 50) and full-term infants (n = 6) admitted to Isala Women and Children's hospital (Zwolle, The Netherlands) who were born during 24-36 or 37-40 weeks of gestation, respectively, were included in this study. Feces were collected during the first six postnatal weeks (n = 109) and their mycobiota composition and diversity were characterized by ITS2 amplicon sequencing. Results: Composition analyses identified fungi and other eukaryotic kingdoms, of which Viridiplantae was most abundant. Of the fungal kingdom, Ascomycota and Basidiomycota were the first and second most prominent phyla in early life of all infants. Candida was the most abundant genus in the first six weeks of life and increased with gestational and postnatal age. Fungal phylogenetic diversity remained stable in the first six postnatal weeks. The individuality and the mode of delivery were identified as significant predictors for the variation in the mycobiota composition. Vaginally delivered infants were enriched in Candida spp., whereas infants delivered through emergency C-section were characterized by Malassezia spp. Conclusion: These results indicate that fungi and other eukaryotic kingdoms are detected in the intestine of preterm and full-term infants in the first six postnatal weeks. Similar to the microbiota, colonization of the preterm intestine with fungi is determined by clinical variables including individuality and mode of delivery.

From Mum to Bum: An Observational Study Protocol to Follow Digestion of Human Milk Oligosaccharides and Glycoproteins from Mother to Preterm Infant

The nutritional requirements of preterm infants are challenging to meet in neonatal care, yet crucial for their growth, development and health. Aberrant maturation of the gastrointestinal tract and the microbiota could affect the digestion of human milk and its nutritional value considerably. Therefore, the main objective of the proposed research is to investigate how the intestinal microbiota of preterm and full-term infants differ in their ability to extract energy and nutrients from oligosaccharides and glycoproteins in human milk. This pilot study will be an observational, single-center study performed at the Neonatal Intensive Care Unit at Isala Women and Children’s Hospital (Zwolle, The Netherlands). A cohort of thirty mother–infant pairs (preterm ≤30 weeks of gestation, n = 15; full-term 37–42 weeks of gestation, n = 15) will be followed during the first six postnatal weeks with follow-up at three- and six-months postnatal age. We will collect human milk of all mothers, gastric aspirates of preterm infants and fecal samples of all infants. A combination of 16S rRNA amplicon sequencing, proteomics, peptidomics, carbohydrate analysis and calorimetric measurements will be performed. The role of the microbiota in infant growth and development is often overlooked yet offers opportunities to advance neonatal care. The ‘From Mum to Bum’ study is the first study in which the effect of a preterm gut microbiota composition on its metabolic capacity and subsequent infant growth and development is investigated. By collecting human milk of all mothers, gastric aspirates of preterm infants and fecal samples of all infants at each timepoint, we can follow digestion of human milk from the breast of the mother throughout the gastrointestinal tract of the infant, or ‘From Mum to Bum’.

Maturation of the preterm gastrointestinal tract can be defined by host and microbial markers for digestion and barrier defense

Functionality of the gastrointestinal tract is essential for growth and development of newborns. Preterm infants have an immature gastrointestinal tract, which is a major challenge in neonatal care. This study aims to improve the understanding of gastrointestinal functionality and maturation during the early life of preterm infants by means of gastrointestinal enzyme activity assays and metaproteomics. In this single-center, observational study, preterm infants born between 24 and 33 weeks (n = 40) and term infants born between 37 and 42 weeks (n = 3), who were admitted to Isala (Zwolle, the Netherlands), were studied. Enzyme activity analyses identified active proteases in gastric aspirates of preterm infants. Metaproteomics revealed human milk, digestive and immunological proteins in gastric aspirates of preterm infants and feces of preterm and term infants. The fecal proteome of preterm infants was deprived of gastrointestinal barrier-related proteins during the first six postnatal weeks compared to term infants. In preterm infants, bacterial oxidative stress proteins were increased compared to term infants and higher birth weight correlated to higher relative abundance of bifidobacterial proteins in postnatal week 3 to 6. Our findings indicate that gastrointestinal and beneficial microbial proteins involved in gastrointestinal maturity are associated with gestational and postnatal age.

Impact of Early Empiric Antibiotic Regimens on the Gut Microbiota in Very Low Birth Weight Preterm Infants: An Observational Study

Frequent use of antibiotics in preterm infants disturbs their gut microbial balance. In this preliminary observational study, we investigated the effect of different antibiotic regimens, administered during the first week of life, on microbial composition and diversity in very low birth weight (VLBW) preterm infants. We performed fecal sampling of breastfed VLBW infants on days 7, 14, and 30. After excluding stool samples from infants who received probiotics or who were administered antibiotics beyond the age of 7 days, we compared gut microbiota profiles between infants receiving a combination of ampicillin and gentamicin for 3 days (AG group, n = 10) and those receiving a combination of ampicillin and cefotaxime for 7 days (AC group, n = 14) using 16S ribosomal DNA community profiling. We also assessed the changes over time in each group. Compared to the AG group, Enterococcus species were significantly more abundant in the AC group (P = 0.002), especially in 7-day samples (12.3 vs. 0.6%, respectively, P = 0.032). No difference was observed at phylum and genus level over time within each group. Species richness in the AC group decreased significantly in the 14-day (P = 0.038) and 30-day (P = 0.03) samples compared to that in the 7-day sample. The same was observed for microbial evenness; in contrast, no significant difference in Shannon index and beta-diversity was detected between the two groups. Controlling for relevant confounding variables did not change the results. In conclusion, different antibiotic regimens affect the early development of gut microbiota in VLBW preterm infants. Prolonged use of ampicillin and cefotaxime might result in overabundance of Enterococcus. However, given that no significant differences were observed in 1-month samples, bacterial genera appear to continue colonizing the gastrointestinal tract despite previous exposure to antibiotics. The clinical relevance of these findings should be elucidated by further studies.

Dynamics of the preterm gut microbiome in health and disease

Advances in metagenomics have allowed a detailed study of the gut microbiome, and its role in human health and disease. Infants born prematurely possess a fragile gut microbial ecosystem that is vulnerable to perturbation. Alterations in the developing gut microbiome in preterm infants are linked to life-threatening diseases such as necrotizing enterocolitis (NEC) and late-onset sepsis; and may impact future risk of asthma, atopy, obesity, and psychosocial disease. In this mini-review, we summarize recent literature on the origins and patterns of development of the preterm gut microbiome in the perinatal period. The host-microbiome-environmental factors that portend development of dysbiotic intestinal microbial patterns associated with NEC and sepsis are reviewed. Strategies to manipulate the microbiome and mitigate dysbiosis, including the use of probiotics and prebiotics will also be discussed. Finally, we explore the challenges and future directions of gut microbiome research in preterm infants.

Composition characteristics of the gut microbiota in infants and young children of under 6 years old between Beijing and Japan

BACKGROUND

The composition of intestinal flora in Chinese and Japanese has been reported in many studies but that in infants aged 0-6 years old has not been studied yet.

METHODS

The distribution characteristics of the fecal flora of infants in Beijing (n=84) and Japan (n=53) were analyzed using 16S rRNA gene sequencing analysis.

RESULTS

This study showed the higher relative abundance of Erysipelotrichaceae_ UCG-003 and Anaerostipes in male group that of Ruminiclostridium, Eubacterium, Senegalimassilia and Senegalimassilia in female group, especially Senegalimassilia, which was not detected in male group. Defecation trait groups indicated significantly higher relative abundance of Bifidobacterium in abnormal bowel trait group than that in the normal group (P<0.05). The feeding groups' analysis showed significantly higher relative abundance of Bifidobacterium and Enterococcus and lower abundance of Bacteroides and Lacetospirillaceae in the breast-feeding group than that in the formula feeding and mixed-feeding groups. The relative abundance of Parasutterella and Ruminococcaceae_UCG-003 in the halitosis group was significantly higher than that in the normal group. The comparison of cold and fever group and normal group indicated significantly higher relative abundance of Erysipelatoclostridium and lower relative abundance of Lachnospiraceae _UCG-001 in the fever and cold group than that in the normal group (P<0.05). The regional comparison of intestinal flora of Beijing and Japan showed significant increase in the relative abundance of Bacillus, Lactobacillus, Prevotella, megamonas and Veillonella in the intestinal flora of 0-6 years old infants in Beijing.

CONCLUSIONS

These findings improve the understanding of intestinal bacterial and viral communities of infants from the two Asian countries.

Dosage Adjustment for Ceftazidime in Pediatric Patients With Renal Impairment Using Physiologically Based Pharmacokinetic Modeling

Physiologically based pharmacokinetic (PBPK) modeling has unique advantages in investigating the pharmacokinetics of drugs in special populations. Our aim is to design optimized dosing regimens for ceftazidime in renally-impaired pediatric patients using PBPK modeling. Models for healthy and renally-impaired adults were developed, verified, and adapted for children to predict ceftazidime exposure in pediatric patients with varying degrees of renal impairment, capturing age- and weight-related pharmacokinetic changes. We derived a dosage-adjusted regimen for renally-impaired children based on pharmacokinetic data and evaluated the pharmacodynamics of ceftazidime. The PBPK models adequately predicted ceftazidime exposures in populations after single- and multi-dose administrations, with fold error values within 1.1 between simulated and observed data. In moderate, severe, and end-stage renally-impaired pediatric patients, the areas under the plasma concentration-time curves (AUCs) were 1.87-fold, 3.56-fold, and 6.19-fold higher, respectively, than in healthy children when treated with the same dose of 50 mg/kg. Pharmacodynamic verification indicated that the recommended doses of 28, 15, and 8 mg/kg administered three times daily (every 8 h) to pediatric patients with moderate, severe, and end-stage renal disease, respectively, were sufficient to attain the target of maintaining the free plasma concentration at or above minimum inhibitory concentration (MIC) during 70% of the dosing interval (70% fT > MIC: nearly 100% target attainment for susceptible MIC of 4 mg/L and >70% for intermediate MIC of 8 mg/L). Our PBPK model can be an effective tool to support dosing recommendations in pediatric patients with different degrees of renal impairment.

Intestinal Stem Cell Development in the Neonatal Gut: Pathways Regulating Development and Relevance to Necrotizing Enterocolitis

The intestine is extremely dynamic and the epithelial cells that line the intestine get replaced every 3–5 days by highly proliferative intestinal stem cells (ISCs). The instructions for ISCs to self-renew or to differentiate come as cues from their surrounding microenvironment or their niche. A small number of evolutionarily conserved signaling pathways act as a critical regulator of the stem cells in the adult intestine, and these pathways are well characterized. However, the mechanisms, nutritional, and environmental signals that help establish the stem cell niche in the neonatal intestine are less studied. Deciphering the key signaling pathways that regulate the development and maintenance of the stem cells is particularly important to understanding how the intestine regenerates from necrotizing enterocolitis, a devastating disease in newborn infants characterized by inflammation, tissues necrosis, and stem cell injury. In this review, we piece together current knowledge on morphogenetic and immune pathways that regulate intestinal stem cell in neonates and highlight how the cross talk among these pathways affect tissue regeneration. We further discuss how these key pathways are perturbed in NEC and review the scientific knowledge relating to options for stem cell therapy in NEC gleaned from pre-clinical experimental models of NEC.

Comparison of the Gut Microbiota Between Pulsatilla Decoction and Levofloxacin Hydrochloride Therapy on Escherichia coli Infection

Gut microbiota serves as a critical indicator for gut health during treatment of pathogenic bacterial infection. Both Pulsatilla Decoction (abbreviated to PD, a traditional Chinese medicine compound) and Levofloxacin Hydrochloride (LVX) were known to have therapeutic effects to intestinal infectious disease. However, the changes of gut microbiota after PD or LVX treatment remain unclear. Herein, this work aimed to investigate the changes of intestinal flora after PD or LVX therapy of Escherichia coli infection in rats. Results revealed that PD exhibited a valid therapeutic approach for E. coli infection via the intestinal protection, as well as the inhibited release of IL-8 and ICAM-1. Besides, PD was beneficial to rebuild the gut microbiota via restoring Bacteroidetes spp in the composition of the gut microbiota. Comparatively, LVX treatment promoted the infection and ravaged gut microbiota by significantly decreasing Bacteroidetes and increasing Firmicutes. These findings not only highlight the mechanism of Chinese herbal formula, but extend the application of PD as veterinary medicine, feed additive and pre-mixing agent for improving the production of animal derived foods.