Detection of CTX-M-15 Extended-Spectrum β-Lactamases Producing Escherichia coli Isolates from Colostrum and Faeces of Newborn Dairy Calves in China

Colostrum as a source of ESBL-Escherichia coli in feces of newborn calves

The aim of the present study was to determine if colostrum and the equipment for harvesting and feeding colostrum are sources of fecal ESBL/AmpC-producing Escherichia coli (ESBL/AmpC-E. coli) in calves. Therefore, 15 male calves fed with pooled colostrum on a dairy farm and held individually in an experimental barn, the colostrum pool and the equipment for harvesting and feeding colostrum were sampled and analyzed for the occurrence of ESBL/AmpC-E. coli. The ESBL-AmpC-E. coli suspicious isolates were subjected to whole-genome sequence analysis. Forty-three of 45 fecal samples were tested positive for ESBL/AmpC-E. coli. In the colostrum sample and in the milking pot, we also found ESBL/AmpC-E. coli. All 45 E. coli isolates were ESBL-producers, mainly commensal sequence type (ST) 10, but also human-extraintestinal pathogenic E. coli ST131 and ST117 were found. The clonal identity of six fecal isolates with the ESBL-E. coli isolate from the colostrum and of five fecal isolates with the strain from the milking pot demonstrates that the hygiene of colostrum or the colostrum equipment can play a significant role in the spread of ESBL-E. coli. Effective sanitation procedures for colostrum harvesting and feeding equipment are crucial to reduce the ESBL-E. coli shedding of neonatal dairy calves.

Microbiological risk assessment and resistome analysis from shotgun metagenomics of bovine colostrum microbiome

Colostrum is known for its nutraceutical qualities, probiotic attributes, and health benefits. The aim of this study was to profile colostrum microbiome from bovine in rural sites of a developing country. The focus was on microbiological safety assessments and antimicrobial resistance, taking into account the risks linked with the consumption of raw colostrum. Shotgun sequencing was employed to analyze microbiome in raw buffalo and cow colostrum. Alpha and beta diversity analyses revealed increased inter and intra-variability within colostrum samples' microbiome from both livestock species. The colostrum microbiome was mainly comprised of bacteria, with over 90% abundance, whereas fungi and viruses were found in minor abundance. Known probiotic species, such as Leuconostoc mesenteroides, Lactococcus lactis, Streptococcus thermophilus, and Lactobacillus paracasei, were found in the colostrum samples. A relatively higher number of pathogenic and opportunistic pathogenic bacteria were identified in colostrum from both animals, including clinically significant bacteria like Clostridium botulinum, Pseudomonas aeruginosa, Escherichia coli, and Listeria monocytogenes. Binning retrieved 11 high-quality metagenome-assembled genomes (MAGs), with three MAGs potentially representing novel species from the genera Psychrobacter and Pantoea. Notably, 175 antimicrobial resistance genes (ARGs) and variants were detected, with 55 of them common to both buffalo and cow colostrum metagenomes. These ARGs confer resistance against aminoglycoside, fluoroquinolone, tetracycline, sulfonamide, and peptide antibiotics. In conclusion, this study describes a thorough overview of microbial communities in buffalo and cow colostrum samples. It emphasizes the importance of hygienic processing and pasteurization in minimizing the potential transmission of harmful microorganisms linked to the consumption of colostrum.

The roles of short-chain fatty acids derived from colonic bacteria fermentation of non-digestible carbohydrates and exogenous forms in ameliorating intestinal mucosal immunity of young ruminants

Short-chain fatty acids (SCFA) are a class of organic fatty acids that consist of 1 to 6 carbons in length. They are primary end-products which arise from non-digestible carbohydrates (NDC) fermentation of colonic bacteria. They are the fundamental energy sources for post-weaning ruminants. SCFA represent the major carbon flux of diet through the gut microbiota to the host. They also play a vital role in regulating cell expansion and gene expression of the gastrointestinal tract (GIT). Recently, remarkable progresses have been made in understanding the immunomodulatory effects of SCFA and their interactions with the host. The processes involved in this study encompassed inflammasome activation, proliferation of lymphocytes, and maturation of intestinal mucosal immunity maturation. It is important to note that the establishment and maturation of intestinal mucosal immune system are intricately connected to the barrier function of intestinal epithelial cells (IEC) and the homeostasis of gut microbiota. Thus, insights into the role of SCFA in enteric mucosal immunoreaction of calves will enhance our understanding of their various regulatory functions. This review aims to analyze recent evidence on the role of SCFA as essential signaling molecules between gut microbiota and animal health. Additionally, we provide a summary of current literature on SCFA in intestinal mucosal immune responses of dairy calves.

Bovine Colostrum: Human and Animal Health Benefits or Route Transmission of Antibiotic Resistance-One Health Perspective

After calving, bovine colostrum is obtained from the mammary gland of the dam in the first days and fed to newborn ruminant to prevent microbial infections. Each bovine colostrum has a unique biochemical composition with high nutraceutical value compared to milk. However, bovine colostrum is influenced by various factors, such as environmental, individual, and genetic factors, as well as processing methods. Proper colostrum management is crucial for obtaining high-quality colostrum and mitigating bacterial contamination. This is important not only for the health and survival of calves but also for the health of humans who consume colostrum and its co-products. It is essential to ensure that the consumed colostrum is free of pathogens to reap its benefits. Health-promoting products based on colostrum have gained significant interest. However, colostrum can contain pathogens that, if not eliminated, can contribute to their transmission and spread, as well as antibiotic resistance. The aim of this review was to promote the animal and human health benefits of bovine colostrum by improving its microbial quality and highlighting potential routes of dissemination of antibiotic-resistant pathogens. Implementing hygienic measures is one of the key factors in mitigating colostrum bacterial contamination and obtaining safe and high-quality colostrum. This helps reduce the exposure of pathogens to newborn calves, other animals, and humans, in a One Health analysis.

Temporal Changes in Fecal Unabsorbed Carbohydrates Relative to Perturbations in Gut Microbiome of Neonatal Calves: Emerging of Diarrhea Induced by Extended-Spectrum β-lactamase-Producing Enteroaggregative Escherichia coli

Early gut microbiota development and colonization are crucial for the long-term health and performance of ruminants. However, cognition among these microbiota is still vague, particularly among the neonatal dairy calves. Here, extended-spectrum β-lactamase-producing enteroaggregative E. coli (ESBL-EAEC)-induced temporal changes in diversity, stability, and composition of gut microbiota were investigated among the neonatal female calves, with the view of discerning potential biomarkers of this arising diarrhea cases in local pastures. Nearly, 116 newborn calves were enrolled in this time period study during their first 2 weeks of life, and a total of 40 selected fecal samples from corresponding calves were used in this study. The results revealed that differentiated gut microbiome and metabolome discerned from neonatal calves were accompanied by bacterial infections over time. Commensal organisms like Butyricicoccus, Faecalibacterium, Ruminococcus, Collinsella, and Coriobacterium, as key microbial markers, mainly distinguish “healthy” and “diarrheic” gut microbiome. Random forest machine learning algorithm indicated that enriched fecal carbohydrates, including rhamnose and N-acetyl-D-glucosamine, and abundant short-chain fatty acids (SCFAs) existed in healthy ones. In addition, Spearman correlation results suggested that the presence of Butyricicoccus, Faecalibacterium, Collinsella, and Coriobacterium, key commensal bacteria of healthy calves, is positively related to high production of unabsorbed carbohydrates, SCFAs, and other prebiotics, and negatively correlated to increased concentrations of lactic acid, hippuric acid, and α-linolenic acid. Our data suggested that ESBL-EAEC-induced diarrhea in female calves could be forecasted by alterations in the gut microbiome and markedly changed unabsorbed carbohydrates in feces during early lives, which might be conducive to conduct early interventions to ameliorate clinical symptoms of diarrhea induced by the rising prevalence of ESBL-EAEC.

Gut microbiota-derived ursodeoxycholic acid from neonatal dairy calves improves intestinal homeostasis and colitis to attenuate extended-spectrum β-lactamase-producing enteroaggregative Escherichia coli infection

BACKGROUND

Antimicrobials are often used to prevent and treat diarrhea induced by enteroaggregative Escherichia coli (EAEC) in young ruminants. However, drug overuse or misuse accelerates the spread of multidrug-resistant extended-spectrum β-lactamase (ESBL)-producing E. coli. Thus, supplementary foods as alternatives to antibiotics are needed to prevent colibacillus diarrhea in neonatal dairy calves. Ursodeoxycholic acid (UDCA), a therapeutic bile acid, helps alleviate colitis. However, how UDCA helps alleviate ESBL-EAEC-induced clinical symptoms and colitis remains unclear.

RESULTS

We investigated the microbial profiles and metabolites of healthy and diarrheic neonatal calves to determine microbial and metabolite biomarkers in early-life development. Both the gut microbiota communities and their associated metabolites differed between healthy and diarrheic calves. Commensal Butyricicoccus, Faecalibacterium, Ruminococcus, Collinsella, and Coriobacterium were key microbial markers that distinguished healthy and diarrheic gut microbiomes. Random forest machine-learning algorithm and Spearman correlation results indicated that enriched UDCA, short-chain fatty acids (SCFAs), and other prebiotics were strongly positively correlated with these five bacterial genera. We explored the effect of ursodiol on bacterial growth, cell adherence, and lipopolysaccharide-treated Caco-2 cells. Adding ursodiol induced direct antibacterial effects, suppressed proinflammatory effects, and reduced cell integrity damage. Oral ursodiol delivery to neonatal mice exhibited significant antibacterial effects and helped maintain colonic barrier integrity in mouse models of peritonitis sepsis and oral infection. UDCA supplementation attenuated colitis and recovered colonic SCFA production. To validate this, we performed fecal microbiota transplantations to inoculate ESBL-EAEC-infected neonatal mice. Microbiotas from UDCA-treated neonatal mice ameliorated colitis and hindgut commensal bacterial damage compared with that of the microbiotas from the control and placebo mice, as evidenced by colonization of abundant bacteria, including Oscillospiraceae, Ruminococcaceae, Lachnospiraceae, and Clostridia_UCG-014, and upregulated SCFA production.

CONCLUSIONS

This study provided the first evidence that UDCA could confer diarrhea resistance in ESBL-EAEC-infected newborn dairy calves. UDCA blocked bacterial growth and invasion both in vitro and in vivo, alleviated commensal bacterial dysbiosis during ESBL-EAEC infection in neonatal mouse models of sepsis and colitis via the TGR5-NF-κB axis, and upregulated SCFA production in the hindgut digesta. Our findings provide insight into the UDCA-mediated remission of ESBL-EAEC infections and the potential role of UDCA as an antibiotic alternative. Video abstract.

Protective Effects of Intestinal Gallic Acid in Neonatal Dairy Calves Against Extended-Spectrum β-lactamase Producing Enteroaggregative Escherichia coli Infection: Modulating Intestinal Homeostasis and Colitis

Calf diarrhea induced by enteroaggregative E. coli (EAEC) spreads fast among young ruminants, causing continuous hazard to dairy industry. Antimicrobial drug abuse aggravates the incidence rate of multi-drug resistant (MDR) extended-spectrum β-lactamase-producing E. coli (ESBL-EC). However, knowledge of detection and significance of disease-related biomarkers in neonatal female calves are still limited. Gallic acid (GA), a natural secondary metabolite mostly derived from plants, has attracted increasing attention for its excellent anti-inflammatory and anti-oxidative properties. However, it is vague how GA engenders amelioration effects on clinical symptoms and colitis induced by ESBL-EAEC infection in neonatal animals. Here, differentiated gut microbiome and fecal metabolome discerned from neonatal calves were analyzed to ascertain biomarkers in their early lives. Commensal Collinsella and Coriobacterium acted as key microbial markers mediating colonization resistance. In addition, there exists a strongly positive relation between GA, short-chain fatty acid (SCFA) or other prebiotics, and those commensals using random forest machine learning algorithm and Spearman correlation analyses. The protective effect of GA pretreatment on bacterial growth, cell adherence, and ESBL-EAEC-lipopolysaccharide (LPS)-treated Caco-2 cells were first assessed, and results revealed direct antibacterial effects and diminished colonic cell inflammation. Then, oral GA mediated colitis attenuation and recovery of colonic short-chain fatty acid (SCFA) productions on neonatal mice peritonitis sepsis or oral infection model. To corroborate this phenomenon, fecal microbiota transplantation (FMT) method was adopted to remedy the bacterial infection. Of note, FMT from GA-treated neonatal mice achieved profound remission of clinical symptoms and colitis over the other groups as demonstrated by antibacterial capability and prominent anti-inflammatory abilities, revealing improved hindgut microbiota structure with enriched Clostridia_UCG-014, Lachnospiraceae, Oscillospiraceae, and Enterococcaceae, and upregulation of SCFA productions. Collectively, our findings provided the direct evidence of hindgut microbiota and intestinal metabolites, discriminating the health status of neonatal calves post ESBL-EAEC infection. The data provided novel insights into GA-mediated remission of colitis via amelioration of hindgut commensal structure and upregulation of SCFA productions. In addition, its eminent role as potential antibiotic alternative or synergist for future clinic ESBL-EAEC control in livestock.