Protection Mechanism of Clostridium butyricum against Salmonella Enteritidis Infection in Broilers

A Review of the Mechanisms of Bacterial Colonization of the Mammal Gut

A healthy animal intestine hosts a diverse population of bacteria in a symbiotic relationship. These bacteria utilize nutrients in the host's intestinal environment for growth and reproduction. In return, they assist the host in digesting and metabolizing nutrients, fortifying the intestinal barrier, defending against potential pathogens, and maintaining gut health. Bacterial colonization is a crucial aspect of this interaction between bacteria and the intestine and involves the attachment of bacteria to intestinal mucus or epithelial cells through nonspecific or specific interactions. This process primarily relies on adhesins. The binding of bacterial adhesins to host receptors is a prerequisite for the long-term colonization of bacteria and serves as the foundation for the pathogenicity of pathogenic bacteria. Intervening in the adhesion and colonization of bacteria in animal intestines may offer an effective approach to treating gastrointestinal diseases and preventing pathogenic infections. Therefore, this paper reviews the situation and mechanisms of bacterial colonization, the colonization characteristics of various bacteria, and the factors influencing bacterial colonization. The aim of this study was to serve as a reference for further research on bacteria-gut interactions and improving animal gut health.

Interplay Between Drug-Induced Liver Injury and Gut Microbiota: A Comprehensive Overview

Drug-induced liver injury is a prevalent severe adverse event in clinical settings, leading to increased medical burdens for patients and presenting challenges for the development and commercialization of novel pharmaceuticals. Research has revealed a close association between gut microbiota and drug-induced liver injury in recent years. However, there has yet to be a consensus on the specific mechanism by which gut microbiota is involved in drug-induced liver injury. Gut microbiota may contribute to drug-induced liver injury by increasing intestinal permeability, disrupting intestinal metabolite homeostasis, and promoting inflammation and oxidative stress. Alterations in gut microbiota were found in drug-induced liver injury caused by antibiotics, psychotropic drugs, acetaminophen, antituberculosis drugs, and antithyroid drugs. Specific gut microbiota and their abundance are associated closely with the severity of drug-induced liver injury. Therefore, gut microbiota is expected to be a new target for the treatment of drug-induced liver injury. This review focuses on the association of gut microbiota with common hepatotoxic drugs and the potential mechanisms by which gut microbiota may contribute to the pathogenesis of drug-induced liver injury, providing a more comprehensive reference for the interaction between drug-induced liver injury and gut microbiota.

Advances in enteropathogen control throughout the meat chicken production chain

Enteropathogens, namely Salmonella and Campylobacter, are a concern in global public health and have been attributed in numerous risk assessments to a poultry source. During the last decade, a large body of research addressing this problem has been published. The literature reviewed contains review articles on certain aspects of poultry production chain; however, in the past decade there has not been a review on the entire chain-farm to fork-of poultry production. For this review, a pool of 514 articles were selected for relevance via a systematic screening process (from >7500 original search articles). These studies identified a diversity of management and intervention strategies for the elimination or reduction of enteropathogens in poultry production. Many studies were laboratory or limited field trials with implementation in true commercial operations being problematic. Entities considering using commercial antienteropathogen products and interventions are advised to perform an internal validation and fit-for-purpose trial as Salmonella and Campylobacter serovars and biovars may have regional diversity. Future research should focus on nonchemical application within the processing plant and how a combination of synergisticinterventions through the production chain may contribute to reducing the overall carcass burden of enteropathogens, coupled with increased consumer education on safe handling and cooking of poultry.

Clostridium butyricum Can Promote Bone Development by Regulating Lymphocyte Function in Layer Pullets

Bone health problems are a serious threat to laying hens; microbiome-based therapies, which are harmless and inexpensive, may be an effective solution for bone health problems. Here, we examined the impacts of supplementation with Clostridium butyricum (CB) on bone and immune homeostasis in pullets. The results of in vivo experiments showed that feeding the pullets CB was beneficial to the development of the tibia and upregulated the levels of the bone formation marker alkaline phosphatase and the marker gene runt-related transcription factor 2 (RUNX2). For the immune system, CB treatment significantly upregulated IL-10 expression and significantly increased the proportion of T regulatory (Treg) cells in the spleen and peripheral blood lymphocytes. In the in vitro test, adding CB culture supernatant or butyrate to the osteoblast culture system showed no significant effects on osteoblast bone formation, while adding lymphocyte culture supernatant significantly promoted bone formation. In addition, culture supernatants supplemented with treated lymphocytes (pretreated with CB culture supernatants) stimulated higher levels of bone formation. In sum, the addition of CB improved bone health by modulating cytokine expression and the ratio of Treg cells in the immune systems of layer pullets. Additionally, in vitro CB could promote the bone formation of laying hen osteoblasts through the mediation of lymphocytes.

Effects of Clostridium butyricum on intestinal environment and gut microbiome under Salmonella infection

Salmonellosis causes massive economic losses globally every year. Especially in poultry, numerous drug-resistant bacteria have emerged; thus, it is imperative to find alternatives to antibiotics. As a probiotic, Clostridium butyricum (C. butyricum) provides the latest strategy for inhibiting the proliferation of Salmonella. This study aimed to evaluate the effects of C. butyricum on intestinal environment and gut microbiome under Salmonella infection. In this study, we modeled the infection of Salmonella using specific pathogen-free (SPF) chicks and found that the use of C. butyricum directly reduced the number of Salmonella colonizations in the spleen and liver. It also alleviated the histopathological changes of the liver, spleen, and cecum caused by Salmonella Enteritidis (S. Enteritidis). In addition, S. Enteritidis increased the expression of pro-inflammatory IL-6 in the cecum on day 6 postinfection. Interestingly, we found that C. butyricum changed PPAR-γ transcript levels in the cecum on day 6 postinfection. Analysis of the chick gastrointestinal microbiome showed that Salmonella infection increased the relative abundance of Subdoligranulum variabile. Further analysis found that Salmonella challenge significantly reduced the relative abundance of Faecalibacterium prausnitzii and C. butyricum increased the relative abundance of anaerobic bacteria in the gut on day 6 postinfection. Moreover, early supplementation of C. butyricum restored the epithelial hypoxia in S. Enteritidis infection in chicks. The results suggest that C. butyricum restores epithelial hypoxia caused by S. Enteritidis, improves the stability of intestinal flora, and inhibits the proliferation of Salmonella.

Single and Combined Effects of Clostridium butyricum and Coccidiosis Vaccine on Growth Performance and the Intestinal Microbiome of Broiler Chickens

Avian coccidiosis is an important intestinal protozoan disease that has caused major economic losses to the poultry industry. Clostridium butyricum can not only maintain the stability of the intestinal barrier, but can also improve the production performance of broiler chickens. We studied the effects of feeding C. butyricum alone, administration of coccidiosis vaccine alone, and the combined administration of C. butyricum and coccidiosis vaccine on body weight gain, feed consumption, and feed conversion ratio of broilers. Meanwhile, intestinal contents of 8- and 15-day-old broilers were collected, and their intestinal microbiome was characterized by high-throughput sequencing of the V3–V4 region of 16S rDNA. We analyzed the oocysts per gram values and lesion scores in the C. butyricum alone group, in a group challenged with the coccidiosis-causing parasite, Eimeria, and in groups simultaneously challenged Eimeria and pretreated with C. butyricum, the coccidiosis vaccine, or combined C. butyricum and coccidiosis vaccine. Intestinal tissue samples were collected from 32-day-old broilers for microbiome analysis. Our results showed that combination of C. butyricum with coccidiosis vaccine significantly improved the performance of broiler chickens and also significantly reduced the oocysts per gram value and intestinal lesions caused by Eimeria sp. infection. Furthermore, C. butyricum and coccidiosis vaccine administered alone or in combination significantly increased the relative abundance of the immune biomarker genus Barnesiella. The significant increase in the abundance of the Clostridia_UCG.014, Eubacterium coprostanoligenes group and Bacteroides was a key factor in controlling Eimeria sp. infection.

Effects of Clostridium butyricum on Growth Performance, Gut Microbiota and Intestinal Barrier Function of Broilers

This study was conducted to evaluate the effects of Clostridium butyricum dietary supplementation on the growth, antioxidant, immune response, gut microbiota, and intestinal barrier function of broilers under high stocking density (HSD) stress. A total of 324 1-day-old Arbor Acres male broilers were randomly assigned to three treatments with six replicates, each replicate including 18 chickens (18 birds/m²). The experiment lasted 6 weeks. The three treatments were basal diet (control, CON), basal diet supplemented with 1 × 10⁹ colony forming units (cfu)/kg C. butyricum (CB), and basal diet supplemented with 10 mg/kg virginiamycin (antibiotic, ANT). The results showed that the body weight (BW) and average daily gain (ADG) of broilers in the CB group were significantly higher than those in the CON group in three periods (p < 0.05). The total antioxidant capacity (T-AOC) and the superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity in serum of the CB group were significantly increased compared with those in the CON and ANT groups at 42 days (p < 0.05). At 42 days, the serum immunoglobulin M (IgM) and immunoglobulin G (IgG) levels of the CB group were significantly higher than those of the CON group. Compared with the CON group, interleukin-1β (IL-1β) in the CB group was significantly decreased in the starter and grower stages (p < 0.05), but there was no significant difference between the two treatment groups (p > 0.05). C. butyricum significantly decreased the high stocking density-induced expression levels of IL-1β and tumor necrosis factor-α (TNF-α) in the ileum of broilers at different stages. Additionally, C. butyricum could increase the expressions of claudin-1 and zonula occludens-1 (ZO-1) in intestinal tissue. Moreover, C. butyricum significantly increased the Sobs and Shannon indices in the CB group compared with the ANT group (p < 0.05), while the Ace index in the CB group was significantly higher than that of the CON group (p < 0.05). Furthermore, by using 16S rRNA gene sequencing, the proportion of Bacteroides in the CB group was increased compared to those in the CON and ANT groups at the genus level. In conclusion, C. butyricum supplemented into feed could improve the growth performance and feed utilization of broilers by promoting immune and intestinal barrier function and benefiting the cecal microflora.

Dietary supplementation with Clostridium butyricum improves growth performance of broilers by regulating intestinal microbiota and mucosal epithelial cells

Clostridium butyricum has been widely considered an antibiotic substitute in recent years. It can promote growth performance, improve the immune response and enhance the intestinal barrier function of the host. In the present study, 1-d-old Arbor Acres (AA) broilers were fed C. butyricum (1 × 10⁹ cfu/kg) for 28 d. The transcriptomic characteristics of epithelial cells of the cecal mucosa were determined by RNA-sequence, and the cecal microbiota composition was explored by 16S ribosomal RNA gene sequencing. The changes in the intestinal mucosa of broilers were then analyzed by tissue staining. Gene Ontology (GO) annotations identified substance transport and processes and pathways that might participate in intestinal development and cell viability. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that the differentially expressed genes are involved in numerous pathways related to amino acid and vitamin metabolism and antioxidant and defensive functions, among others. The relative expression of some genes associated with intestinal barrier function (claudins 2, 15, 19, and 23, tight junction proteins 1, 2, and 3 and mucin 1) was significantly increased in the treatment group (P < 0.05 or P < 0.01). Moreover, the proportion of Firmicutes was higher in the C. butyricum-treated group, whereas the proportion of Proteobacteria was higher in the control group. At the genus level, the relative abundances of Butyricicoccus and Lactobacillus, among other bacteria, were increased after C. butyricum supplementation. The tissue staining analysis showed that the cecal mucosa of broilers was significantly ameliorated after the addition of C. butyricum (P < 0.05 or P < 0.01). These results showed that dietary supplementation with C. butyricum can enhance the antioxidant capacity, mucosal barrier function, and stabilize the cecal microbiota, resulting in improving the growth performance.

Clostridium butyricum CB1 up-regulates FcRn expression via activation of TLR2/4-NF-κB signaling pathway in porcine small intestinal cells

The neonatal Fc receptor (FcRn) mediates the bidirectional transport of immunoglobulin G (IgG) across hyperpolarized epithelial cells. Overexpression of FcRn increases serum IgG and humoral immune response. Probiotics can improve the host's serum and intestinal mucosal IgG. However, whether probiotics regulate FcRn and its specific mechanism are still unclear. Our research showed that heat inactivated Clostridium butyricum CB1 (heat-inactivated CB1) up-regulated FcRn expression in porcine small intestinal epithelial (IPI-2I) cells. Furthermore, heat-inactivated CB1 stimulation activated the nuclear factor kappa B (NF-κB) signaling pathway. Moreover, FcRn expression decreased after blocking the NF-κB signaling pathway by NF-κB inhibitor BAY11-7028, suggesting that heat-inactivated CB1 induced FcRn expression via the NF-κB signaling pathway. Using small interfering RNAs (siRNAs), we found that knockdown of TLR2/4, MyD88 and TRIF reduced NF-κB activity induced by heat-inactivated CB1, as well as up-regulation of FcRn expression after heat-inactivated CB1 stimulation. Taken together, our data indicated that heat-inactivated CB1 up-regulated FcRn expression via TLR2/4-MyD88/TRIF-NF-κB signaling pathway. These results provided a new perspective for us to understand the enhancement of C. butyricum on intestinal mucosal immunity.

Effects of Dietary Supplementation with Clostridium butyricum on Growth Performance, Serum Immunity, Intestinal Morphology, and Microbiota as an Antibiotic Alternative in Weaned Piglets

This study investigated the effects of Clostridium butyricum (C. butyricum) use on growth performance, serum immunity, intestinal morphology, and microbiota as an antibiotic alternative in weaned piglets. Over the course of 28 days, 120 piglets were allocated to four treatments with six replicates of five piglets each. The treatments were: CON (basal diet); AGP (basal diet supplemented with 0.075 g/kg chlortetracycline, 0.055 g/kg kitasamycin, and 0.01 g/kg virginiamycin); CBN (basal diet supplemented with normal dosage of 2.5 × 10⁸ CFU/kg C. butyricum); and CBH (basal diet supplemented with high dosage of 2.5 × 10⁹ CFU/kg C. butyricum). Body weight (BW) and feed consumption were recorded at the beginning and on days 14 and 28 of the experiment, and representative feed samples and fresh feces were collected from each pen between days 26 and 28. Average fecal score of diarrhea was visually assessed each morning during the experimental period. On the morning of days 14 and 28, blood samples were collected to prepare serum for immune and antioxidant parameters measurement. One male piglet close to the average group BW was selected from each replicate and was slaughtered on day 21 of the experiment. Intestinal crypt villi, and colonic microbiota and its metabolites short-chain fatty acids were measured. Compared to the CON group, the CBN and AGP groups significantly decreased (p < 0.05) the ratio of feed to weight gain by 8.86% and 8.37% between days 1 and 14, 3.96% and 13.36% between days 15 and 28, 5.47% and 11.44% between days 1 and 28. Dietary treatment with C. butyricum and AGPs significantly decreased the average fecal score during the experimental period (p < 0.05). The apparent total tract digestibility of dry matter, organic matter, and total carbohydrates in the CBH group were higher respectively at 3.27%, 2.90%, and 2.97%, than those in the CON or AGP groups (p < 0.05). Compared to the CON group, the CBH group significantly increased short-chain fatty acids in colon and villus height in the jejunum (p < 0.05). The CBN group had higher serum levels of immunoglobulins, interleukin 2 (IL-2), and glutathione peroxidase (GSH-PX) activity, but lower serum levels of IL-1β and IL-6, and a lower aspartate aminotransferase (AST), alkaline phosphatase (ALP), and gamma-glutamyl transpeptidase (γ-GT) activity (p < 0.05), while compared to the CON group. Dietary treatment with C. butyricum significantly increased the relative abundance of Streptococcus and Bifidobacterium (p < 0.05). In summary, diet with C. butyricum increased the growth performance and benefited the health of weaned piglets.

State-of-the-Art of the Nutritional Alternatives to the Use of Antibiotics in Humans and Monogastric Animals

Simple Summary

Antibiotic resistance represents a worldwide recognized issue affecting both human and veterinary medicine, with a particular focus being directed towards monogastric animals destined for human consumption. This scenario is the result of frequent utilization of the antibiotics either for therapeutic purposes (humans and animals) or as growth promoters (farmed animals). Therefore, the search for nutritional alternatives has progressively been the object of significant efforts by the scientific community. So far, probiotics, prebiotics and postbiotics are considered the most promising products, as they are capable of preventing or treating gastrointestinal diseases as well as restoring a eubiosis condition after antibiotic-induced dysbiosis development. This review provides an updated state-of-the-art of these nutritional alternatives in both humans and monogastric animals.

Abstract

In recent years, the indiscriminate use of antibiotics has been perpetrated across human medicine, animals destined for zootechnical productions and companion animals. Apart from increasing the resistance rate of numerous microorganisms and generating multi-drug resistance (MDR), the nonrational administration of antibiotics causes sudden changes in the structure of the intestinal microbiota such as dysbiotic phenomena that can have a great clinical significance for both humans and animals. The aim of this review is to describe the state-of-the-art of alternative therapies to the use of antibiotics and their effectiveness in humans and monogastric animals (poultry, pigs, fish, rabbits, dogs and cats). In particular, those molecules (probiotics, prebiotics and postbiotics) which have a direct function on the gastrointestinal health are herein critically analysed in the prevention or treatment of gastrointestinal diseases or dysbiosis induced by the consumption of antibiotics.

Clostridium butyricum Ameliorates Salmonella Enteritis Induced Inflammation by Enhancing and Improving Immunity of the Intestinal Epithelial Barrier at the Intestinal Mucosal Level

This study was aimed to investigate the effects of Clostridium butyricum (C. butyricum) immunity and intestinal epithelial barrier function at the intestinal mucosal level, by using Salmonella enteritidis (S. enteritidis) to infect specific-pathogen-free (SPF) chickens and intestinal epithelial cells (IEC). We found that C. butyricum could decrease cytokine levels (IFN-γ, IL-1β, IL-8, and TNF-α) via the TLR4-, MyD88-, and NF-κB-dependent pathways in intestinal tissues and intestinal epithelial cells. Additionally, C. butyricum could attenuate bacteria-induced intestinal damage and increase the expression level of muc-2 and ZO-1 in the intestine and intestinal epithelial cells. Furthermore, C. butyricum altered the intestinal microbial composition, increased the diversity of the bacterial communities in the cecum of Salmonella-infected chickens. In conclusion, C. butyricum effectively attenuated inflammation and epithelial barrier damage, altered the intestinal microbial composition, increased the diversity of the bacterial communities in the intestine of Salmonella-infected chickens. The result suggests that C. butyricum might be an effective and safe therapy for the treatment of Salmonella infection.

Screening of single or combined administration of 9 probiotics to reduce ammonia emissions from laying hens

The effects of single/combined administration of 9 probiotics on ammonia (NH3) emissions during in vitro fermentation of the caecal contents of laying hens were studied. Not all of the probiotics reduced NH3 emissions. Pichia farinose, Bacillus coagulans, Lactobacillus plantarum, Pichia guilliermondii, and Bacillus subtilis reduced NH3 production by approximately 35.1 to 39%. Compared with the control group, the greatest NH3 inhibition was achieved via the combined application of P. guilliermondii, B. subtilis, and L. plantarum at 1:2:1, resulting in a 46% reduction. Effective probiotics use decreased crude protein digestibility, pH, ammonium nitrogen, valerate levels, and urease and uricase activity, but increased urea, purine trione, nitrate nitrogen, total volatile fatty acids, and acetate levels. The relative abundance of the bacteria responsible for fermenting carbohydrates to produce short fatty acids was increased. Under different treatments, the KEGG Orthology (KO) metabolic pathways of NH3 production and utilization were diverse. Hence, the application of probiotics to control NH3 emissions is dependent on the types and combined ratio of the organisms involved.

The Effect of Clostridium butyricum on Gut Microbiota, Immune Response and Intestinal Barrier Function During the Development of Necrotic Enteritis in Chickens

Necrotic enteritis (NE) causes huge economic losses to the poultry industry. Probiotics are used as potential alternatives to antibiotics to prevent NE. It is known that Clostridium butyricum can act as a probiotic that can prevent infection. However, whether or not it exerts a beneficial effect on NE in chickens remains elusive. Therefore, we investigated the impact of C. butyricum on immune response and intestinal microbiota during the development of NE in chickens, including experimental stages with basal diets, high-fishmeal-supplementation diets, and Clostridium perfringens challenge. Chickens were divided into two groups from day 1 to day 20: one group had its diet supplemented with C. butyricum supplementation and one did not. At day 20, the chickens were divided into four groups: C. perfringens challenged and unchallenged chickens with and without C. butyricum supplementation. All groups were fed a basal diet for 13 days and thereafter a basal diet with 50% fishmeal from day 14 to 24. Chickens were infected with C. perfringens from day 21 to 23. At days 13, 20 and 24, samples were collected for analysis of the relative expression of immune response and intestinal mucosa barrier-related genes and intestinal microbes. The results show that C. butyricum can inhibit the increase in IL-17A gene expression and the reduction in Claudin-1 gene induced-expression caused by C. perfringens challenge. Moreover, C. butyricum was found to increase the expression of anti-inflammatory IL-10 in infected chickens. Although C. butyricum was found to have a significant beneficial effect on the structure of intestinal bacteria in the basal diet groups and decrease the abundance of C. perfringens in the gut, it did not significantly affect the occurrence of intestinal lesions and did not significantly correct the shift in gut bacterial composition post C. perfringens infection. In conclusion, although C. butyricum promotes the expression of anti-inflammatory and tight junction protein genes and inhibits pro-inflammatory genes in C. perfringens-challenged chickens, it is not adequate to improve the structure of intestinal microbiota in NE chickens. Therefore, more effective schemes of C. butyricum supplementation to prevent and treat NE in chickens need to be identified.

Effects of Clostridium butyricum and Enterococcus faecalis on growth performance, intestinal structure, and inflammation in lipopolysaccharide-challenged weaned piglets

This study was conducted to investigate the effects of Clostridium butyricum and Enterococcus faecalis on growth performance, immune function, inflammation-related pathways, and microflora community in weaned piglets challenged with lipopolysaccharide (LPS). One hundred and eighty 28-d-old weaned piglets were randomly divided into 3 treatments groups: piglets fed with a basal diet (Con), piglets fed with a basal diet containing 6 × 109 CFU C. butyricum·kg-1 (CB), and piglets fed with a basal diet containing 2 × 1010 CFU E. faecali·kg-1 (EF). At the end of trial, 1 pig was randomly selected from for each pen (6 pigs per treatment group) and these 18 piglets were orally challenged with LPS 25 μg·kg-1 body weight. The result showed that piglets fed C. butyricum and E. faecalis had greater final BW compared with the control piglets (P < 0.05). The C. butyricum and E. faecalis fed piglets had lower levels of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), IL-1β, tumor inflammatory factor-α (TNF-α), and had greater level of serum interferon-γ (IFN-γ) than control piglets at 1.5 and 3 h after injection with LPS (P < 0.05). Furthermore, piglets in the C. butyricum or E. faecalis treatment groups had a greater ratio of jejunal villus height to crypt depth (V/C) compared with control piglets after challenge with LPS for 3 h (P < 0.05). Compared with the control treatment, the CB and EF treatments significantly decreased the expression of inflammation-related pathway factors (TLR4, MyD88, and NF-κB) after challenge with LPS for 3 h (P < 0.05). High-throughput sequencing revealed that C. butyricum and E. faecalis modulated bacterial diversity in the colon. The species richness and alpha diversity (Shannon) of bacterial samples in CB or EF piglets challenged with LPS were higher than those in LPS-challenged control piglets. Furthermore, the relative abundance of Bacteroidales-Rikenellanceae in the CB group was higher than that in the control group (P < 0.05), whereas EF piglets had a higher relative abundance of Lactobacillus amylovorus and Lactobacillus gasseri (P < 0.05). In conclusion, dietary supplementation with C. butyricum or E. faecalis promoted growth performance, improved immunity, relieved intestinal villus damage and inflammation, and optimized the intestinal flora in LPS-challenged weaned piglets.

Therapeutic effects of probiotic Clostridium butyricum WZ001 on bacterial vaginosis in mice

AIMS

To observe the therapeutic effects of vaginal infusion of probiotic Clostridium butyricum WZ001 on bacterial vaginosis (BV) in mice.

METHODS AND RESULTS

Female ICR mice were used to establish the model of BV by infecting oestrogen-treated mice with Escherichia coli, and then treated with high- and low dose of C. butyricum. Clinical indexes of mice in the C. butyricum-treated groups were significantly improved and comparable to those in the antibiotic group. Pap staining showed that neutrophil count was significantly increased after modelling and largely decreased after C. butyricum treatment (P < 0·01). Dynamic observation of E. coli and Lactobacillus showed that the number of E. coli significantly decreased in the C. butyricum-treated groups or in the antibiotic group with prolonged treatment (P < 0·01). Besides, the number of E. coli in the low-dose C. butyricum group was higher than that in either its high-dose counterpart or the antibiotic group respectively (P < 0·01). The number of Lactobacillus decreased evidently in the antibiotic group (P < 0·01), while that in the C. butyricum groups remained consistent. Moreover, C. butyricum inhibited the proliferation of E. coli by the experiment in vitro. The phosphorylation of nuclear factor-kappa B (NF-κB) p65 in vaginal tissue and the serum levels of inflammatory cytokines, IL-1β, TNF-α and IL-6, increased after modelling and significantly decreased after treated with C. butyricum (P < 0·01), with no difference found when compared with the antibiotic group.

CONCLUSION

Clostridium butyricum inhibits the growth of pathogenic bacteria as well as the inflammatory response induced by E. coli and promotes the growth of Lactobacillus to maintain the vaginal micro-ecological balance.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results suggest that probiobitc C. butyricum WZ001 has a great potential in the clinical treatment of BV.