Anti-infectious activity of synbiotics in a novel mouse model of methicillin-resistant Staphylococcus aureus infection

Gut microbiota associated with the mitigation effect of synbiotics on adverse events of neoadjuvant chemotherapy in patients with esophageal cancer: A retrospective exploratory study

Introduction. Our synbiotics (Lacticaseibacillus paracasei strain Shirota, Bifidobacterium breve strain Yakult, and galacto-oligosaccharides: LBG) helps mitigate serious adverse events such as febrile neutropenia (FN) and diarrhoea in oesophageal cancer patients receiving neoadjuvant chemotherapy (NAC). Unfortunately, LBG therapy does not benefit all patients.Hypothesis/Gap Statement. Identification of the gut microbiota species involved in adverse events during chemotherapy could help predict the onset of adverse events. Identification of the gut microbiota that influence the efficacy of LBG could also help establish a diagnostic method to identify patients who will respond to LBG before the initiation of therapy.Aim. To identify the gut microbiota involved in adverse events during NAC and that affect the efficacy of LBG therapy.Methodology. This study was ancillary to a parent randomized controlled trial in which 81 oesophageal cancer patients were recruited and administered either prophylactic antibiotics or LBG combined with enteral nutrition (LBG+EN). The study included 73 of 81 patients from whom faecal samples were collected both before and after NAC. The gut microbiota was analysed using 16S rRNA gene amplicon sequencing and compared based on the degree of NAC-associated adverse events. Furthermore, the association between the counts of identified bacteria and adverse events and the mitigation effect of LBG+EN was also analysed.Results. The abundance of Anaerostipes hadrus and Bifidobacterium pseudocatenulatum in patients with no FN or only mild diarrhoea was significantly higher (P<0.05) compared to those with FN or severe diarrhoea. Moreover, subgroup analyses of patients receiving LBG+EN showed that the faecal A. hadrus count before NAC was significantly associated with a risk of developing FN (OR, 0.11; 95 % CI, 0.01-0.60, P=0.019). The faecal A. hadrus count after NAC was positively correlated with intestinal concentrations of acetic acid (P=0.0007) and butyric acid (P=0.00005).Conclusion. Anaerostipes hadrus and B. pseudocatenulatum may be involved in the ameliorating adverse events and can thus be used to identify beforehand patients that would benefit from LBG+EN during NAC. These results also suggest that LBG+EN would be useful in the development of measures to prevent adverse events during NAC.

Bifidobacterium: Host-Microbiome Interaction and Mechanism of Action in Preventing Common Gut-Microbiota-Associated Complications in Preterm Infants: A Narrative Review

The development and health of infants are intertwined with the protective and regulatory functions of different microorganisms in the gut known as the gut microbiota. Preterm infants born with an imbalanced gut microbiota are at substantial risk of several diseases including inflammatory intestinal diseases, necrotizing enterocolitis, late-onset sepsis, neurodevelopmental disorders, and allergies which can potentially persist throughout adulthood. In this review, we have evaluated the role of Bifidobacterium as commonly used probiotics in the development of gut microbiota and prevention of common diseases in preterm infants which is not fully understood yet. The application of Bifidobacterium as a therapeutical approach in the re-programming of the gut microbiota in preterm infants, the mechanisms of host-microbiome interaction, and the mechanism of action of this bacterium have also been investigated, aiming to provide new insights and opportunities in microbiome-targeted interventions in personalized medicine.

Efficacy of Lactobacillus fermentum Isolated from the Vagina of a Healthy Woman against Carbapenem-Resistant Klebsiella Infections In Vivo

Carbapenem-resistant Enterobacteriaceae (CRE) that produce Klebsiella pneumoniae carbapenemase are increasingly reported worldwide and have become more and more resistant to nearly all antibiotics during the past decade. The emergence of K. pneumoniae strains with decreased susceptibility to carbapenems, which are used as a last resort treatment option, is a significant threat to hospitalized patients worldwide as K. pneumoniae infection is responsible for a high mortality rate in the elderly and immunodeficient individuals. This study used Lactobacillus fermentum as a candidate probiotic for treating CRE-related infections and investigated its effectiveness. We treated mice with L. fermentum originating from the vaginal fluid of a healthy Korean woman and evaluated the Lactobacilli's efficacy in preventive, treatment, non-establishment, and colonization mouse model experiments. Compared to the control, pre-treatment with L. fermentum significantly reduced body weight loss in the mouse models, and all mice survived until the end of the study. The oral administration of L. fermentum after carbapenemresistant Klebsiella (CRK) infection decreased mortality and illness severity during a 2-week observation period and showed that it affects other strains of CRK bacteria. Also, the number of Klebsiella bacteria was decreased to below 5.5 log₁₀ CFU/ml following oral administration of L. fermentum in the colonization model. These findings demonstrate L. fermentum's antibacterial activity and its potential to treat CRE infection in the future.

Non-Digestible Oligosaccharides and Short Chain Fatty Acids as Therapeutic Targets against Enterotoxin-Producing Bacteria and Their Toxins

Enterotoxin-producing bacteria (EPB) have developed multiple mechanisms to disrupt gut homeostasis, and provoke various pathologies. A major part of bacterial cytotoxicity is attributed to the secretion of virulence factors, including enterotoxins. Depending on their structure and mode of action, enterotoxins intrude the intestinal epithelium causing long-term consequences such as hemorrhagic colitis. Multiple non-digestible oligosaccharides (NDOs), and short chain fatty acids (SCFA), as their metabolites produced by the gut microbiota, interact with enteropathogens and their toxins, which may result in the inhibition of the bacterial pathogenicity. NDOs characterized by diverse structural characteristics, block the pathogenicity of EPB either directly, by inhibiting bacterial adherence and growth, or biofilm formation or indirectly, by promoting gut microbiota. Apart from these abilities, NDOs and SCFA can interact with enterotoxins and reduce their cytotoxicity. These anti-virulent effects mostly rely on their ability to mimic the structure of toxin receptors and thus inhibiting toxin adherence to host cells. This review focuses on the strategies of EPB and related enterotoxins to impair host cell immunity, discusses the anti-pathogenic properties of NDOs and SCFA on EPB functions and provides insight into the potential use of NDOs and SCFA as effective agents to fight against enterotoxins.

Antimicrobial and Immunomodulatory Effects of Bifidobacterium Strains: A Review

Bifidobacterium strains can provide several health benefits, such as antimicrobial and immunomodulatory effects. Some strains inhibit growth or cell adhesion of pathogenic bacteria, including multidrug-resistant bacteria, and their antibacterial activity can be intensified when combined with certain antibiotics. In addition, some strains of bifidobacteria reduce viral infectivity, leading to less epithelial damage of intestinal tissue, lowering the virus shedding titer, and controlling the release of antiviral substances. Furthermore, bifidobacteria can modulate the immune system by increasing immunoglobulins, and inducing or reducing pro- or antiinflammatory cytokines, respectively. In particular, these anti-inflammatory effects are helpful in the treatment of patients who are already suffering from infection or inflammatory diseases. This review summarizes the antimicrobial effects and mechanisms, and immunomodulatory effects of Bifidobacterium strains, suggesting the potential of bifidobacteria as an alternative or complementary treatment option.

Pathways of Methicillin-Resistant Staphylococcus aureus in Animal Model: New Insights Regarding Public Health

Background

Staphylococcus aureus is considered one of the major threats regarding food safety worldwide. Methicillin-resistant S. aureus (MRSA) strains in livestock, companion animals, and wild animals continue to be a potential risk to people working with them.

Aim

The current research aims to investigate the potential pathways of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) strains in the body after oral infection using the experimental mouse model.

Methods

Seven groups of SPF male mice were purchased and housed. On day 1, six groups of mice were infected orally by the sterile gastric probe using 100 μL/mice of LA-MRSA bacterial suspension (1 × 10⁸ colony-forming units (CFU)/mL). The remaining group was kept as negative controls. Over 15 days, these animals have been monitored. Fresh fecal samples were screened for LA-MRSA at day 0, day 7 and day 14 following oral administration of MRSA strains. All animals were sacrificed at day 15, and internal organs (liver, lung, kidney, and intestine) were harvested aseptically and divided into two sections. The first part was histopathologically investigated, while the other half has been tested for LA-MRSA re-isolation.

Result

The oral challenge of mice by MRSA strains showed that MRSA was re-isolated from feces and intestines of all inoculated mice groups and from internal organs (liver, lung, kidney and intestine) of most mice. Results were confirmed by the detection of the bacteria in gram-stained tissue sections and changes in H&E-stained histopathological tissue sections from these organs.

Conclusion

Data from the present study indicate the possible colonization of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) in internal organs following oral infection and thus posing a risk for food-borne infection of MRSA. Infected animals could pass LA-MRSA through feces again, resulting in increased dispersion and environmental contamination.

The Battle of Probiotics and Their Derivatives Against Biofilms

Biofilm-related infections have been a major clinical problem and include chronic infections, device-related infections and malfunction of medical devices. Since biofilms are not fully available for the human immune system and antibiotics, they are difficult to eradicate and control; therefore, imposing a global threat to human health. There have been avenues to tackle biofilms largely based on the disruption of their adhesion and maturation. Nowadays, the use of probiotics and their derivatives has gained a growing interest in battling against pathogenic biofilms. In the present review, we have a close look at probiotics with the ultimate objective of inhibiting biofilm formation and maturation. Overall, insights into the mechanisms by which probiotics and their derivatives can be used in the management of biofilm infections would be warranted.

Dimensionally Enhanced Antibacterial Library Screening

The emergence and spread of antimicrobial resistance is a major public health threat, and there is an urgent need to develop new strategies to address the issue. In this study, the possibility of enhancing a whole cell based antibacterial library screen by increasing the dimensionality of the screening effort is explored using methicillin-resistant Staphylococcus aureus (MRSA) as the target organism. One dimension involved generating and screening a human liver microsome metabolized FDA approved drug library. Comparative screening of the un-metabolized (UM) and pre-metabolized (PM) libraries allows identification of intrinsically active agents from the UM library screen and of agents with active metabolites from the PM library screen. To further enhance this screening effort, it was combined with a -/+ resistant to antibiotic screen (-/+ cefoxitin; Cef). This allows the identification of agents that can act synergistically with the resistant to antibiotic. This approach revealed five compounds with substantially improved activity after metabolism and four compounds with substantial synergistic activity with cefoxitin. Capecitabine in particular only had significant antibacterial activity after metabolism. Its metabolites were isolated, identified, and characterized for spectrum of activity along with several other anticancer drugs with anti-MRSA activity. Floxuridine, gemcitabine, novobiocin, and rifaximin were identified as having substantial synergy with cefoxitin from the -/+Cef screens. Checkerboard assays verified synergy for these agents. Floxuridine demonstrated a particularly high degree of synergy with cefoxitin (FIC = 0.14). This study demonstrates how a dimensionally enhanced comparative screening effort can identify new antibacterial agents and strategies for countering antibacterial agent resistance.

Randomized study of the effect of synbiotics during neoadjuvant chemotherapy on adverse events in esophageal cancer patients

BACKGROUND AND AIMS

The clinical value of synbiotics in patients receiving neoadjuvant chemotherapy currently remains unclear. The aim of this study was to investigate the effects of synbiotics in esophageal cancer patients receiving neoadjuvant chemotherapy on the intestinal microbiota and the adverse events of chemotherapy.

METHODS

Sixty-one patients with advanced esophageal cancer who were scheduled to receive neoadjuvant chemotherapy were randomly allocated to 2 groups. One group received synbiotics during chemotherapy (n = 30), while the other group did not (n = 31). The fecal microbiota and organic acid concentrations were analyzed. The primary endpoint was the incidence of chemotherapy-related adverse events.

RESULTS

The numbers of beneficial and harmful bacteria were significantly larger and smaller, respectively, in the synbiotics group than in the control group on day 10 of chemotherapy. The concentrations of acetic acid and propionic acid were significantly higher in the synbiotics group on day 10 of chemotherapy. The frequencies of severe lymphopenia and diarrhea were significantly less in the synbiotics group than in the control group (P = 0.033, 0.035, respectively). Furthermore, febrile neutropenia occurred less in the synbiotics group (10/30 in the synbiotics group vs 19/31 in the control group, P = 0.029).

CONCLUSIONS

Synbiotics during neoadjuvant chemotherapy in esophageal cancer patients reduced the occurrence of adverse events of chemotherapy through adjustments to the intestinal microbiota. (University Hospital Medical Information Network (http://www.umin.ac.jp), registration number UMIN000006875).

Effect of Lactobacillus plantarum on Intestinal Infection in Multiple Drug-Resistant Bacteria Mice

BACKGROUND

This study aimed to determine the effects of probiotic Lactobacillus plantarum on colitis in mice with multiple drug-resistant bacteria, and to judge the intervention function of probiotics in the resistance of pathogenic bacteria.

METHODS

Male BALB/C mice were divided into four groups. The colonic tissues were collected for pathology observation, permeability, transepithelial electrical resistance (TER), and tight junction protein expression detection at death, and the feces were collected for detecting drug susceptibility of MDR-PA.

RESULTS

MDR-PA mice developed severe intestinal inflammation and tissue damage in which paracellular permeability was increased, in conjunction with decreased expression and redistribution. LP administration attenuated colitis of MDR-PA mice. The drug susceptibility diameter of MDR-PA has increased.

CONCLUSION

Probiotics can treat diarrhea of mice by MDR-PA and protect the intestinal barrier function. Probiotics can weaken the resistance of multiple drug resistance in Pseudomonas aeruginosa to some extent.

Randomized clinical trial of the effect of perioperative synbiotics versus no synbiotics on bacterial translocation after oesophagectomy

BACKGROUND

The impact of perioperative synbiotics on bacterial translocation and subsequent bacteraemia after oesophagectomy is unclear. This study investigated the effect of perioperative synbiotic administration on the incidence of bacterial translocation to mesenteric lymph nodes (MLNs) and the occurrence of postoperative bacteraemia.

METHODS

Patients with oesophageal cancer were randomized to receive perioperative synbiotics or no synbiotics (control group). MLNs were harvested from the jejunal mesentery before dissection (MLN-1) and after the restoration of digestive tract continuity (MLN-2). Blood and faeces samples were taken before and after operation. Microorganisms in each sample were detected using a bacterium-specific ribosomal RNA-targeted reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) method.

RESULTS

Some 42 patients were included. There was a significant difference between the two groups in detection levels of microorganisms in the MLN-1 samples. Microorganisms were more frequently detected in MLN-2 samples in the control group than in the synbiotics group (10 of 18 versus 3 of 18; P = 0·035). In addition, bacteraemia detected using RT-qPCR 1 day after surgery was more prevalent in the control group than in the synbiotics group (12 of 21 versus 4 of 21; P = 0·025). Neutrophil counts on postoperative days 1, 2 and 7 after surgery were all significantly higher in the control group than in the synbiotics group.

CONCLUSION

Perioperative use of synbiotics reduces the incidence of bacteria in the MLNs and blood. These beneficial effects probably contribute to a reduction in the inflammatory response after oesophagectomy.

REGISTRATION NUMBER

ID 000003262 (University Hospital Medical Information Network, http://www.umin.ac.jp).

Role of probiotics in the prevention and treatment of meticillin-resistant Staphylococcus aureus infections

Meticillin-resistant Staphylococcus aureus (MRSA) is a multidrug-resistant micro-organism and is the principal nosocomial pathogen worldwide. Following initial in vitro experiments demonstrating that Lactobacillus acidophilus CL1285(®) and Lactobacillus casei LBC80R(®) commercial strains exhibit antibacterial activity against clinical MRSA isolates, we conducted a literature search to find any evidence of probiotic efficacy in decolonisation or treatment of S. aureus infection. As summarised below, many strains of lactobacilli and bifidobacteria isolated from a variety of sources inhibited the growth of S. aureus and clinical isolates of MRSA in vitro. The most active strains were Lactobacillus reuteri, Lactobacillus rhamnosus GG, Propionibacterium freudenreichii, Propionibacterium acnes, Lactobacillus paracasei, L. acidophilus, L. casei, Lactobacillus plantarum, Lactobacillus bulgaricus, Lactobacillus fermentum and Lactococcus lactis. Their effects were mediated both by direct cell competitive exclusion as well as production of acids or bacteriocin-like inhibitors. L. acidophilus also inhibited S. aureus biofilm formation and lipase production. In vitro antimicrobial activity did not necessarily assure efficacy in vivo in animal infectious models, e.g. S. aureus 8325-4 was most sensitive in vitro to L. acidophilus, whilst in vivo Bifidobacterium bifidum best inhibited experimental intravaginal staphylococcosis in mice. On the other hand, L. plantarum, which showed the highest inhibition activity against S. aureus in vitro, was also very effective topically in preventing skin wound infection with S. aureus in mice. Very few clinical data were found on the interactions between probiotics and MRSA, but the few identified clinical cases pointed to the feasibility of elimination or reduction of MRSA colonisation with probiotic use.

Probiotic/synbiotic therapy for treating critically ill patients from a gut microbiota perspective

The gut is an important target organ for stress caused by severe insults such as sepsis, trauma, burn, shock, bleeding and infection. Severe insult to the gut is considered to have an important role in promoting infectious complications and multiple organ dysfunction syndrome. These are sequelae of interactions between deteriorated intestinal epithelium, the immune system and commensal bacteria. The gut is the "motor" of multiple organ failure, and now it is recognized that gut dysfunction is a causative factor in disease progression. The gut flora and environment are significantly altered in critically ill patients, and the number of obligate anaerobes is associated with prognosis. Synbiotic therapy is a combination of probiotics and prebiotics. Probiotic, prebiotic and synbiotic treatment has been shown to be a promising therapy to maintain and repair the gut microbiota and gut environment. In the critically ill, such as major abdominal surgery, trauma and ICU patients, synbiotic therapy has been shown to significantly reduce septic complications. Further basic and clinical research would clarify the underlying mechanisms of the therapeutic effect of probiotic/synbiotic treatment and define the appropriate conditions for use.