Determination of the extent of Clostridium difficile colonisation and toxin accumulation in sows and neonatal piglets

Influence of high- and low-fermentable dietary fibres in sows' diet on the colostrum potential against Clostridioides difficile toxin-induced effects in IPEC-J2 cells

Sow colostrum has been reported to protect the IPEC-J2 cells and piglet colon tissues from detrimental effect of Clostridioides difficile toxins. Since dietary fibre can influence the colostrum composition in sows, we hypothesised that it can also differentially affect the colostrum potential against C. difficile toxin-induced effects in IPEC-J2. IPEC-J2 were incubated with colostrum from sows fed either high-fermentable sugar beet pulp (SBP) or low-fermentable lignocellulose (LNC) fibres and in combination with the toxins and analysed by trans-epithelial electrical resistance (TEER) and cell viability using propidium iodide in flow cytometry. Toxins drastically decreased the integrity of IPEC-J2. Colostrum from the sows fed either SBP or LNC exerted protective effect against toxins on IPEC-J2 integrity and this effect was numerically superior in the SBP group. Differences in the percentages of TEER between different treatments were noted after 2 h (p = 0.043), 3 h (p = 0.017) and 4 h (p = 0.017) of incubation and a tendency for differences was noted after 5 h of incubation (p = 0.071). Colostrum from either SBP- or LNC-fed sows did not protect the IPEC-J2 from toxin-induced death. Colostrum of the sows fed either high-fermentable or low-fermentable fibres has a potential to protect IPEC-J2 from the loss of integrity, which may be important in protection from C. difficile-infection development in neonatal piglets.

Antimicrobial resistance- and pathogen patterns in the fecal microbiota of sows and their offspring in German commercial pig farms

Reducing antibiotic use is one of the biggest challenges in pig farming, as antibiotics have been used for years to control typical problems such as newborn or post-weaning diarrhea. The pressure a one health approach has created on animal production regarding antimicrobial resistance is an opportunity to find other strategies against enterobacterial pathogens in suckling and weaned piglets. A farm-specific approach could have a good success due to the individual farm structures in Germany and other countries. In this study, non-metric multidimensional scaling, hierarchical clustering, and latent class analysis were used to determine the impact of antibiotic use on antibiotic resistance patterns and pathogen prevalence in 20 German pig farms. This may help to develop individualized health strategies. 802 fresh fecal samples were collected from sows and piglets from 20 piglet production and rearing farms at different production times (sows antepartum and postpartum, suckling piglets, weaned piglets). In addition, the use of antibiotics was recorded. DNA extracts were subjected to quantitative real-time qPCR with primers specific for antibiotic resistance genes (int1, sul1-3, dfrA1, mcr-1, blaCTX-M), and virulence factors of relevant bacteria (C. difficile, C. perfringens, Salmonella, Escherichia/Shigella/Hafnia, E. coli). Linear and logistic regression models were used to analyze the relationship between different antibiotics and the major genes contributing to the clustering of observations for the different animal groups. Clustering revealed different farm clusters for sows, suckling piglets, and weaned piglets, with the most remarkable diversity in antibiotic use among weaned piglets. Amoxicillin, lincomycin, and enrofloxacin were identified as the most probable cause of increased odds of the presence of relevant antibiotic resistance genes (mcr1, dfrA1, blaCTX-M). Still, direct effects of a specific antibiotic on its associated resistance gene were rare. Enrofloxacin and florfenicol favored the occurrence of C. difficile in sows. The E. coli fimbriae genes were less affected by antibiotic use in sows and piglets, but the F4 fimbriae gene could be associated with the integrase 1 gene in piglets. The results confirm that multidrug-resistant enterobacteria are widespread in German pig farms and give awareness of the impact of current antibiotic use while searching for alternative health strategies.

Clostridial diarrheas in piglets: A review

Clostridium perfringens type C and Clostridioides difficile are the main enteric clostridial pathogens of swine and are both responsible for neonatal diarrhea in this species. The role of Clostridum perfringes type A is under discussion. History, clinical signs, gross lesions and histological findings are the basis for a presumptive diagnosis of C. perfringens type C or C. difficile infection. Confirmation is based upon detection of beta toxin of C. perfringens type C or toxin A/B of C. difficile, respectively, in intestinal contents or feces. Isolation of C. perfringens type C and/or C. difficile is highly suggestive of infection by these microorganisms but it is not enough to confirm a diagnosis as they may be found in the intestine of some healthy individuals. Diagnosis of C. perfringens type A-associated diarrhea is more challenging because the diagnostic criteria have not been well defined and the specific role of alpha toxin (encoded by all strains of this microorganism) and beta 2 toxin (produced by some type A strains) is not clear. The goal of this paper is to describe the main clostridial enteric diseases of piglets, including etiology, epidemiology, pathogenesis, clinical signs, pathology and diagnosis.

Clostridioides difficile-mesocolonic oedema in neonatal suckling piglets develops regardless of the fibre composition in sow's diets

Maternal dietary factors have been reported to influence Clostridioides difficile colonisation in the offspring. Twenty suckling piglets from sows fed diets supplemented with high-fermentable sugar beet pulp (SBP) or low-fermentable lignocellulose (LNC) fibres during gestation and lactation were dissected in the first week after birth. Postmortem analysis included clinical mesocolon and faecal scoring, concentration of C. difficile and respective toxins in colon digesta and faeces, immunoglobulins in serum and inflammatory markers in serum and colon tissues. Sow colostrum was assessed for nutrients, immunoglobulins and biogenic amines. Toxin-neutralising IgG antibodies were measured in colostrum and serum of the sows, and in colon digesta and serum of the piglets. Mesocolonic oedema of different severity was present in most of the piglets from both sows' feeding groups. Concentrations of C. difficile, toxins and calprotectin in colon digesta and faecal contents did not differ between the study piglets. Calprotectin correlated positively with mesocolon score (rho = 413, P = 0.07). Piglets from sows fed LNC vs SBP tended to have higher IgA (P = 0.089), IgG (P = 0.053), total Ig (P = 0.053), albumin (P = 0.075) and total protein content (P = 0.007) in serum. Colon tissues of piglets from the SFB vs LNC had upregulated expression of ZO-1 (P = 0.021), PCNA (P = 0.015) and TGF-β (P = 0.014). Titers of anti-toxin-IgG-antibodies in serum and colostrum and in piglet colon digesta and serum did not differ between sows from both dietary groups, but they all showed strong positive correlations. In conclusion, dietary sugar beet pulp or lignocellulose fed to sows did not influence the concentrations of C. difficile and toxins titers in colon digesta and faeces of neonatal piglets.

Fiber Composition in Sows' Diets Modifies Clostridioides difficile Colonization in Their Offspring

Dietary fiber has a potential to modulate the gut microbiota in sows. We hypothesized that a maternal diet rich in either high- or low-fermentable fiber during gestation and lactation influences Clostridioides difficile gut colonization in suckling piglets. Twenty sows were fed gestation and lactation diets enriched with either high-fermentable sugar beet pulp (SBP) or low-fermentable lignocellulose (LNC) fibers. C. difficile, toxin B (TcdB), fecal score, microbial abundance (16S-rDNA sequencing) and metabolites were measured in the feces from the sows and their piglets. C. difficile concentration was higher in piglets from the sows fed LNC than SBP along the study (P ≤ 0.05). Higher prevalence of C. difficile was noted in three-week-old piglets from sows fed LNC vs. SBP (45% vs. 0%, P = 0.001). TcdB prevalence was higher in six-day-old piglets from the sows fed LNC vs. SBP (60% vs. 17%, P = 0.009). In sows, fecal microbial metabolites were higher in SBP than LNC, while C. difficile concentration showed no difference. Higher microbial diversity Shannon index was noted in sows from SBP vs. LNC one week before parturition and at the parturition (P ≤ 0.05). Piglets from SBP vs. LNC tended to have higher microbial diversity Shannon index at two and three weeks of age. Diets enriched with high-fermentable fiber compared to low-fermentable fiber in sows reduced C. difficile colonization in their piglets. Susceptibility to colonization by C. difficile in neonatal piglets can be modulated by the sows' diet, supporting the hypothesis of the early microbial programming in the offspring and the importance of the sow-piglet couple.

A Preliminary Survey of the Distribution of Segmented Filamentous Bacteria in the Porcine Gastrointestinal Tract

Segmented filamentous bacteria (SFB) are present in various animal species including pigs. The aim of this work was to analyze the occurrence of SFB in different parts of the gastrointestinal tract of piglets of different ages. A total of 377 DNA extracts from stomach, jejunum, ileum, cecum and colon digesta, and from feces collected on different time points, originating from 155 animals, were screened by qPCR method with primers specific for the SFB. SFB sequences were detected in 74 of 377 samples (19.6%) from 155 animals in total. SFB were most abundant in ileum (50.0%), cecum (45.0%), and colon (37.0%), followed by feces (14.6%). SFB prevalence in sows was 12.9% (13/101) and 75.9% (41/54) in individual piglets. Of the 41 SFB-positive piglets, only two samples were from pre-weaning animals, while the rest of samples originated from post-weaning piglets. SFB sequences are abundant in post-weaning piglets, but not in suckling or adult animals. They are most abundant in the ileum and cecum of pigs. Further studies are warranted to reveal the role of SFB in pigs.

Editorial for the Special Issue: Clostridium difficile

Clostridium difficile (reclassified as Clostridioides difficile [...].

Porcine Colostrum Protects the IPEC-J2 Cells and Piglet Colon Epithelium against Clostridioides (syn. Clostridium) difficile Toxin-Induced Effects

Clostridioides difficile toxins are one of the main causative agents for the clinical symptoms observed during C. difficile infection in piglets. Porcine milk has been shown to strengthen the epithelial barrier function in the piglet’s intestine and may have the potential to neutralise clostridial toxins. We hypothesised that porcine colostrum exerts protective effects against those toxins in the IPEC-J2 cells and in the colon epithelium of healthy piglets. The IPEC-J2 cells were treated with either the toxins or porcine colostrum or their combination. Analyses included measurement of trans-epithelial electrical resistance (TEER), cell viability using propidium iodide by flow cytometry, gene expression of tight junction (TJ) proteins and immune markers, immunofluorescence (IF) histology of the cytoskeleton and a TJ protein assessment. Colon tissue explants from one- and two-week-old suckling piglets and from five-week-old weaned piglets were treated with C. difficile toxins in Ussing chamber assays to assess the permeability to macromolecules (FITC-dextran, HRP), followed by analysis of gene expression of TJ proteins and immune markers. Toxins decreased viability and integrity of IPEC-J2 cells in a time-dependent manner. Porcine colostrum exerted a protective effect against toxins as indicated by TEER and IF in IPEC-J2 cells. Toxins tended to increase paracellular permeability to macromolecules in colon tissues of two-week-old piglets and downregulated gene expression of occludin in colon tissues of five-week-old piglets (p = 0.05). Porcine milk including colostrum, besides other maternal factors, may be one of the important determinants of early immune programming towards protection from C. difficile infections in the offspring.

Developing Gut Microbiota Exerts Colonisation Resistance to Clostridium (syn. Clostridioides) difficile in Piglets

Clostridium (syn. Clostridioides) difficile is considered a pioneer colonizer and may cause gut infection in neonatal piglets. The aim of this study was to explore the microbiota-C. difficile associations in pigs. We used the DNA from the faeces of four sows collected during the periparturient period and from two to three of their piglets (collected weekly until nine weeks of age) for the determination of bacterial community composition (sequencing) and C. difficile concentration (qPCR). Furthermore, C. difficile-negative faeces were enriched in a growth medium, followed by qPCR to verify the presence of this bacterium. Clostridium-sensu-stricto-1 and Lactobacillus spp. predominated the gut microbiota of the sows and their offspring. C. difficile was detected at least once in the faeces of all sows during the entire sampling period, albeit at low concentrations. Suckling piglets harboured C. difficile in high concentrations (up to log₁₀ 9.29 copy number/g faeces), which gradually decreased as the piglets aged. Enrichment revealed the presence of C. difficile in previously C. difficile-negative sow and offspring faeces. In suckling piglets, the C. difficile level was negatively correlated with carbohydrate-fermenting bacteria, and it was positively associated with potential pathogens. Shannon and richness diversity indices were negatively associated with the C. difficile counts in suckling piglets. This study showed that gut microbiota seems to set conditions for colonisation resistance against C. difficile in the offspring. However, this conclusion requires further research to include host-specific factors.

Storage procedures and time influence the detectability of Clostridium difficile toxin A but not toxin B in porcine fecal specimens

Storage procedures are known to affect the detectability of Clostridium difficile toxins in equine and human feces. We assessed the impact of different storage conditions on the detectability of C. difficile toxins in swine feces. Specimens were inoculated with toxins, 112 ng/g of toxin A (TcdA) and 16 ng/g of toxin B (TcdB) and subjected to the following 3 storage treatments: 4°C, −30°C, repetitive freezing at −30°C and thawing. Toxin determination was assessed at 1, 2, 7, 14, and 21 d with ELISA. A decrease in concentrations of TcdA with time was observed for samples stored at 4°C and repetitive freezing–thawing (p ≤0.05). On day 14, storage at 4°C resulted in decreased TcdA concentration as opposed to storage at −30°C and repetitive freezing–thawing (p ≤0.05). On day 21, storage at 4°C resulted in decreased TcdA detectability compared with storage at −30°C (p ≤0.05). The TcdB concentration was unaffected. These results on toxin detectability in swine feces should be carefully considered in in vitro studies on toxigenic C. difficile. Our results also offer valuable information for microbiologists and veterinarians monitoring the presence of virulent C. difficile in pigs.

Diversity analysis of intestinal microflora between healthy and diarrheal neonatal piglets from the same litter in different regions

Though the problem of neonatal piglet diarrhea is well known, the differences in the bacterial diversity and community composition between healthy and diarrheal piglets are still unknown. We investigated these differences in neonatal piglets from Jiangxi Province, China. Healthy (H, n = 20) and diarrheal (D, n = 20) piglets were selected from six regions. The fecal microbial communities were analyzed by sequencing the V3V4 region of 16S rRNA gene. We found the ratio of major phyla (Fusobacteria, Bacteroidetes, Firmicutes and Proteobacteria) was >99% of 7 phyla. The overall alpha diversity indices, such as chao, sobs, coverage and Shannon, were not significantly different. Moreover, the relative abundance of the predicted functions was highly similar in the two groups. Our results indicated that Clostridium was divided into two major groups: Clostridium sensu stricto_1 and stricto_2. Sensu stricto_2 was highly abundant in the D group and low abundance in the H group, whereas the results of sensu stricto_1 were opposite. Comparative analyses within the H or D groups showed that Escherichia-Shigella and Streptococcus at the genus level and unclassified Lactobacillus at the species level were significant difference. Comparative analyses of the two groups showed that unclassified Prevotellaceae at the genus level and Fusobacterium mortifierum were significantly different and had high linear discriminant analysis (LDA) scores. The significantly different microbes composition results also existed in the same litter, based on excluding regions influence. These results suggested that piglet diarrhea was closely associated with these microbes. This study provides insights into gut microbial interactions and prevention of piglet diarrhea.

Impact of early-life events on the susceptibility to Clostridium difficile colonisation and infection in the offspring of the pig

Clostridium difficile has been documented as a major cause of uncontrolled outbreaks of enteritis in neonatal pigs and antibiotic-associated infections in clinical settings. It belongs to the natural cohort of early colonisers of the gastrointestinal tract of pigs and can be detected in faeces up to two weeks post-partum. In older pigs, it often remains under the detection limit. Most neonatal pigs show no clinical signs of disease although C. difficile and its toxins can be detected at high levels in faeces. Increased mortality rates associated with C. difficile on pig farms are, so far, considered "spontaneous" and the predisposing factors are mostly not defined. The infection caused by C. difficile is multifactorial and it is likely that the repertoire of maternal factors, host physiology, the individually developing gut microbiota, co-infections and environmental stress define the conditions for disease development. In this addendum to our recently published work on CDI in neonatal piglets, we discuss the "early-life events" that influence C. difficile spread and infection in neonatal piglets.

An Engineered Synthetic Biologic Protects Against Clostridium difficile Infection

Morbidity and mortality attributed to Clostridium difficile infection (CDI) have increased over the past 20 years. Currently, antibiotics are the only US FDA-approved treatment for primary C. difficile infection, and these are, ironically, associated with disease relapse and the threat of burgeoning drug resistance. We previously showed that non-toxin virulence factors play key roles in CDI, and that colonization factors are critical for disease. Specifically, a C. difficile adhesin, Surface Layer Protein A (SlpA) is a major contributor to host cell attachment. In this work, we engineered Syn-LAB 2.0 and Syn-LAB 2.1, two synthetic biologic agents derived from lactic acid bacteria, to stably and constitutively express a host-cell binding fragment of the C. difficile adhesin SlpA on their cell-surface. Both agents harbor conditional suicide plasmids expressing a codon-optimized chimera of the lactic acid bacterium's cell-wall anchoring surface-protein domain, fused to the conserved, highly adherent, host-cell-binding domain of C. difficile SlpA. Both agents also incorporate engineered biocontrol, obviating the need for any antibiotic selection. Syn-LAB 2.0 and Syn-LAB 2.1 possess positive biophysical and in vivo properties compared with their parental antecedents in that they robustly and constitutively display the SlpA chimera on their cell surface, potentiate human intestinal epithelial barrier function in vitro, are safe, tolerable and palatable to Golden Syrian hamsters and neonatal piglets at high daily doses, and are detectable in animal feces within 24 h of dosing, confirming robust colonization. In combination, the engineered strains also delay (in fixed doses) or prevent (when continuously administered) death of infected hamsters upon challenge with high doses of virulent C. difficile. Finally, fixed-dose Syn-LAB ameliorates diarrhea in a non-lethal model of neonatal piglet enteritis. Taken together, our findings suggest that the two synthetic biologics may be effectively employed as non-antibiotic interventions for CDI.

Porcine and bovine Clostridium difficile ribotype 078 isolates demonstrate similar growth and toxigenic properties

Clostridioides (C.) difficile are found in cows, pigs and poultry suggesting that this pathogen is present and more importantly animals could act as a reservoir, via food or environment, of human C. difficile infection. Molecular methods together with phenotypical characterisation bring integrated and important tools to describe diversity and nature of bacteria including C. difficile. Moreover, similar or identical C. difficile types are found in different farm animals. This study aimed to phenotypically characterise C. difficile isolates belonging to ribotype 078 and to identify differences such as growth and toxicity between porcine and bovine isolates. C. difficile isolates were assessed for the growth behaviour (turbidimetry), metabolic potential (Biolog AN) and toxin production (ELISA method) in vitro. The concentration of released either toxin A (TcdA) or toxin B (TcdB) varied greatly between the isolates tested; however, it did not differ between the porcine and bovine ribotypes. Also, the TcdA/TcdB ratio of the isolates did not show a difference either. The most common metabolised substrates were pyruvic acid followed by α-ketobutyric acid. The results show that both porcine and bovine C. difficile RT 078 share similar phenotypical characteristics including growth and production of toxins. The findings may help understand the virulence of C. difficile RT 078 in porcine and bovine species.