Effect of oral administration of microcin Y on growth performance, intestinal barrier function and gut microbiota of chicks challenged with Salmonella Pullorum

The lasso peptide microcin Y (MccY) effectively inhibits various serotypes of Salmonella in vitro, but the antibacterial effect against S. Pullorum in poultry is still unclear. This study was the first to evaluate the safety and anti-S. Pullorum infection of MccY in specific pathogen-free (SPF) chicks. The safety test showed that the body weight, IgA and IgM levels of serum, and cecal microbiota structure of 3 groups of chicks orally administrated with different doses of MccY (5 mg/kg, 10 mg/kg, 20 mg/kg) for 14 days were not significantly different from those of the control group. Then, the chicks were randomized into 3 groups for the experiment of anti-S. Pullorum infection: (I) negative control group (NC), (II) S. Pullorum-challenged group (SP, 5 × 108 CFU/bird), (III) MccY-treated group (MccY, 20 mg/kg). The results indicated that compared to the SP group, treatment of MccY increased body weight and average daily gain (P < 0.05), reduced S. Pullorum burden in feces, liver, and cecum (P < 0.05), enhanced the thymus, and decreased the spleen and liver index (P < 0.05). Additionally, MccY increased the jejunal villus height, lowered the jejunal and ileal crypt depth (P < 0.05), and upregulated the expression of IL-4, IL-10, ZO-1 in the jejunum and ileum, as well as CLDN-1 in the jejunum (P < 0.05) compared to the SP group. Furthermore, MccY increased probiotic flora (Barnesiella, etc.), while decreasing (P < 0.05) the relative abundance of pathogenic flora (Escherichia and Salmonella, etc.) compared to the SP group.

Protective effect of plantaricin bio-LP1 bacteriocin on multidrug-resistance Escherichia Coli infection by alleviate the inflammation and modulate of gut-microbiota in BALB/c mice model

The rapid spread of multidrug-resistant pathogens with the low efficacy of common antibiotics for humans and animals in its clinical therapeutics are a global health concern. Therefore, there is a need to develop new treatment strategies to control them clinically. The study aimed to evaluate the effects of Plantaricin Bio-LP1 bacteriocin produced from Lactiplantibacillus plantarum NWAFU-BIO-BS29 to alleviate the inflammation caused by multidrug-resistance Escherichia Coli (MDR-E. coli) infection in BALB/c mice-model. The focus was given on aspects linked to the mechanism of the immune response. Results indicated that Bio-LP1 had highly promising effects on partially ameliorating MDR-E. coli infection by reducing the inflammatory response through inhibiting the overexpression of proinflammatory-cytokines such as secretion of tumor necrosis factor (TNF-α) and interleukin (IL-6 and IL-β) and strongly regulated theTLR4 signaling-pathway. Additionally, avoided the villous destruct, colon length shortening, loss of intestinal barrier integrity, and increased disease activity index. Furthermore, significantly increased the relative abundance of beneficial-intestinal-bacteria including Ligilactobacillus, Enterorhabdus, Pervotellaceae, etc. Finally, improved the intestinal mucosal barrier to alleviate the pathological damages and promote the production of short-chain fatty acids (SCFAs) a source of energy for the proliferation. In conclusion, plantaricin Bio-LP1 bacteriocin can be considered a safe alternative to antibiotics against MDR-E. coli-induced intestinal inflammation.

Biochemical, genetic and transcriptional characterization of multibacteriocin production by the anti-pneumococcal dairy strain Streptococcus infantarius LP90

Streptococcus pneumoniae infections are one of the major causes of morbility and mortality worldwide. Although vaccination and antibiotherapy constitute fundamental and complementary strategies against pneumococcal infections, they present some limitations including the increase in non-vaccine serotypes and the emergence of multidrug-resistances, respectively. Ribosomally-synthesized antimicrobial peptides (i.e. bacteriocins) produced by Lactic Acid Bacteria (LAB) may represent an alternative or complementary strategy to antibiotics for the control of pneumococal infections. We tested the antimicrobial activity of 37 bacteriocinogenic LAB, isolated from food and other sources, against clinical S. pneumoniae strains. Streptococcus infantarius subsp. infantarius LP90, isolated from Venezuelan water-buffalo milk, was selected because of its broad and strong anti-pneumococcal spectrum. The in vitro safety assessment of S. infantarius LP90 revealed that it may be considered avirulent. The analysis of a 19,539-bp cluster showed the presence of 29 putative open reading frames (ORFs), including the genes encoding 8 new class II-bacteriocins, as well as the proteins involved in their secretion, immunity and regulation. Transcriptional analyses evidenced that the induction factor (IF) structural gene, the bacteriocin/IF transporter genes, the bacteriocin structural genes and most of the bacteriocin immunity genes were transcribed. MALDI-TOF analyses of peptides purified using different multichromatographic procedures revealed that the dairy strain S. infantarius LP90 produces at least 6 bacteriocins, including infantaricin A₁, a novel anti-pneumococcal two-peptide bacteriocin.

SPECT/CT imaging of chemotherapy-induced tumor apoptosis using 99mTc-labeled dendrimer-entrapped gold nanoparticles

Non-invasive imaging of apoptosis in tumors induced by chemotherapy is of great value in the evaluation of therapeutic efficiency. In this study, we report the synthesis, characterization, and utilization of radionuclide technetium-99m (99mTc)-labeled dendrimer-entrapped gold nanoparticles (Au DENPs) for targeted SPECT/CT imaging of chemotherapy-induced tumor apoptosis. Generation five poly(amidoamine) (PAMAM) dendrimers (G5.NH2) were sequentially conjugated with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), polyethylene glycol (PEG) modified duramycin, PEG monomethyl ether, and fluorescein isothiocyanate (FI) to form the multifunctional dendrimers, which were then utilized as templates to entrap gold nanoparticles. Followed by acetylation of the remaining dendrimer surface amines and radiolabeling of 99mTc, the SPECT/CT dual mode nanoprobe of tumor apoptosis was constructed. The developed multifunctional Au DENPs before and after 99mTc radiolabeling were well characterized. The results demonstrate that the multifunctional Au DENPs display favorable colloidal stability under different conditions, own good cytocompatibility in the given concentration range, and can be effectively labeled by 99mTc with high radiochemical stability. Furthermore, the multifunctional nanoprobe enables the targeted SPECT/CT imaging of apoptotic cancer cells in vitro and tumor apoptosis after doxorubicin (DOX) treatment in the established subcutaneous tumor model in vivo. The designed duramycin-functionalized Au DENPs might have the potential to be employed as a nanoplatform for the detection of apoptosis and early tumor response to chemotherapy.

Risks Related to High-Dosage Recombinant Antimicrobial Peptide Microcin J25 in Mice Model: Intestinal Microbiota, Intestinal Barrier Function, and Immune Regulation

Antimicrobial peptide (AMP) can be a promising alternative in various domains. However, further risk information is required. In this study, mice were orally administrated different dosages of recombinant AMP microcin J25 (4.55, 9.1, and 18.2 mg/kg; MccJ25) for 1 week, and the toxicity risk impacts were examined. We evidenced that middle-dosage administration mice had a lower inflammation, better body weight, and ameliorated mucosal morphology, accompanied by reduced intestinal permeability and tighter intestinal barrier. Fecal microbiota composition analysis in middle- or low-dosage mice revealed the Bifidobacterium count was increased and the coliform bacteria count was decreased, and increased in short-chain fatty acid levels. Unexpectedly, there was a risk that high-dosage mice increased intestinal permeability and imbalance of intestinal bacteria. Taken together, these data indicated a safe threshold for usage of MccJ25 in clinical practice. Such studies can effectively enhance the safety of various aspects such as food preservative and drug.

Use of the Antimicrobial Peptide Sublancin with Combined Antibacterial and Immunomodulatory Activities To Protect against Methicillin-Resistant Staphylococcus aureus Infection in Mice

Methicillin-resistant Staphylococcus aureus (MRSA) is the major pathogen causing serious hospital infections worldwide. With the emergence and rapid spread of drug-resistant bacteria, there is extraordinary interest in antimicrobial peptides (AMPs) as promising candidates for the treatment of antibiotic-resistant bacterial infections. Sublancin, a glycosylated AMP produced by Bacillus subtilis 168, has been reported to possess protective activity against bacterial infection. This study was performed to evaluate the efficacy of sublancin in the prevention of MRSA ATCC43300 intraperitoneal infection in mice. We determined that sublancin had a minimal inhibitory concentration of 15 μM against MRSA ATCC43300. The antimicrobial action of sublancin involved the destruction of the bacterial cell wall. Dosing of mice with sublancin greatly alleviated (p < 0.05) the bacterial burden caused by MRSA intraperitoneal infection and considerably reduced the mortality and weight loss (19.2 ± 0.62 g vs 20.6 ± 0.63 g for MRSA vs 2.0 mg/kg sublancin, respectively, on day 3) of MRSA-challenged mice (p < 0.05). Sublancin was further found to balance the immune response during infection and relieve intestinal inflammation through inhibition of NF-κB activation (p < 0.01). With their combined antibacterial and immunomodulatory activities, sublancin may have potent therapeutic potential for drug-resistant infections and sepsis.

Clinical research on ultrasonically guided intrahepatic injections of HAS in interventional treatment of liver carcinomas

PURPOSE

To study the clinical value of intrahepatic injections of Highly Agglutinative Staphylococcin (HAS) in the interventional treatment of liver carcinomas.

METHODS

Under ultrasonic guidance, intrahepatic injections of HAS were administered in 22 cases of pathologically diagnosed liver carcinomas, 3 days, 7 days, 30 days, 3 months, 6 months, 9 months, and 12 months after microwave coagulation therapy. The dose of each injection was 2000U.

RESULTS

Immunohistochemical staining of the sample from the tumor site after HAS administrations demonstrated a significant increase in the number of antitumor immune cells compared with that before the injections (p<0.01) and an improvement in local immune status. One-year survival rate and recurrence rate, which were determined by Kaplan- Meier method, were 93.8% and 81.9% respectively.

CONCLUSIONS

As a new route of administration, intrahepatic injections of HAS are a safe and effective procedure and deserves further clinical research and discussion.

The antimicrobial peptide sublancin ameliorates necrotic enteritis induced by Clostridium perfringens in broilers

Sublancin is an antimicrobial peptide produced by 168 containing 37 amino acids. The objective of this study was to investigate its inhibitory efficacy against both in vitro and in vivo. In the in vitro study, we determined that sublancin had a minimum inhibitory concentration of 8 μM against , which was much higher than the antibiotic lincomycin (0.281 μM). Scanning electron microscopy showed that sublancin damaged the morphology of . The in vivo study was conducted on broilers for a 28-d period using a completely randomized design. A total of 252 chickens at 1 d of age were randomly assigned to 1 of 6 treatments including an uninfected control; an infected control; 3 infected groups supplemented with sublancin at 2.88, 5.76, or 11.52 mg activity/L of water; and an infected group supplemented with lincomycin at 75 mg activity/L of water (positive control). Necrotic enteritis was induced in the broilers by oral inoculation of on d 15 through 21. Thereafter, the sublancin or lincomycin were administered fresh daily for a period of 7 days. The challenge resulted in a significant decrease in ADG ( < 0.05) and a remarkable deterioration in G:F ( < 0.05) during d 15 to 21 of the experiment. There was a sharp increase of numbers in the cecum ( < 0.05). The addition of sublancin or lincomycin reduced caecal counts ( < 0.05). The counts had a tendency to decrease in the lincomycin treatment ( = 0.051) but were the highest in the sublancin treatment (5.76 mg activity/L of water). A higher villus height to crypt depth ratio in the duodenum and jejunum as well as a higher villus height in the duodenum were observed in broilers treated with sublancin or lincomycin ( < 0.05) compared with infected control broilers. It was observed that sublancin and lincomycin decreased IL-1β, IL-6, and tumor necrosis factor-α levels ( < 0.05) in the ileum compared with the infected control. In conclusion, although sublancin's minimum inhibitory concentration is much higher than lincomycin in vitro, less sublancin is needed to control necrotic enteritis induced by in vivo than lincomycin. These novel findings indicate that sublancin could be used as a potential antimicrobial agent to control necrotic enteritis.

Characterization of [(99m)Tc]Duramycin as a SPECT Imaging Agent for Early Assessment of Tumor Apoptosis

PURPOSE

We investigated the usefulness of [(99m)Tc]duramycin for monitoring early response to cancer therapy in mice, with an eye towards clinical translation.

PROCEDURES

[(99m)Tc]Duramycin was injected in healthy CD1-/- mice to estimate human [(99m)Tc]duramycin radiation dose. [(99m)Tc]Duramycin single-photon emission computed tomography (SPECT) imaging of apoptosis was evaluated in a mouse model of colorectal cancer treated with irinotecan and validated ex vivo using autoradiography, cleaved caspase-3, and TdT-mediated dUTP nick-end labeling (TUNEL) histology of the tumors.

RESULTS

The mean effective dose was estimated to be 3.74 × 10(-3) ± 3.43 × 10(-4) mSv/MBq for non-purified and 3.19 × 10(-3) ± 2.16 × 10(-4) mSv/MBq for purified [(99m)Tc]duramycin. [(99m)Tc]Duramycin uptake in vivo following therapy increased significantly in apoptotic irinotecan-treated tumors (p = 0.008). Radioactivity in the tumors positively correlated with cleaved caspase-3 (r = 0.85, p < 0.001) and TUNEL (r = 0.92, p < 0.001) staining.

CONCLUSION

[(99m)Tc]Duramycin can be used to detect early chemotherapy-induced tumor cell death, and thus, may be a prospective candidate for clinical SPECT imaging of tumor response to therapy.

Interventional Catheterization Combined with Staphylococcin Aureus Injection in 112 Cases of Ischemic Necrosis of Femoral Heads

The objective of this study was to investigate the effectiveness of interventional catheterization with staphylococcin aureus injection on ischemic necrosis of the femoral heads. By percutaneous catheterization of the femoral artery, papaverine, urokinase, compound Danshen, and anisodamine were injected intravenously into the arteries of the femoral head. Staphylococcin aureus injection was injected into the hit joint capsule on the side of the lesion to compare the conditions before and after surgery. The patients did the rehabilitation exercises of the hit joint 48 h after the surgery and had double crutches for 3-6 months. Of the 112 cases, 39 cases (34.8 %) were cured, 51 cases (45.6 %) were markedly effective, and 22 cases (19.6 %) were effective. Interventional catheterization combined with staphylococcin aureus injection given into the hit joint capsule is an effective way to treat ischemic necrosis of the femoral head by influencing the internal and external environments of the femoral head.

Bioprotective potential of bacteriocinogenic Enterococcus gallinarum strains isolated from some Nigerian fermented foods, and of their bacteriocins

Enterococcus gallinarum strains isolated from some Nigerian fermented foods were found to produce bacteriocins. The bacteriocins had a broad spectrum of activity against both Gram-positive and negative bacteria. The effects of the bacteriocins and bacteriocinogenic organ- isms on Staphylococcus aureus infections in rats were evaluated. Sprague-Dawley rats were infected with S. aureus MTCC 737 and treated with E. gallinarum T71 and different concentrations of the bacteriocins from E. gallinarum W211 and T71. Staphylococcus aureus infection caused significant upregulation of aspartate aminotransferase and alanine aminotransferase levels in sera of the infected rats. Moreover, gelatin zymography revealed that infected gastric tissues showed elevated matrix metalloproteinase-9 activity. Bacteriocin treatments reduced the MMP-9 activity and inhibited the expressions of both Tumour Necrosis Factor Alpha (TNF-α) and Interleukin-1 Beta (IL-1β) dose dependently, pointing to a potential role of the bacteriocins in attenuating inflammatory responses to Staphylococcus aureus infec- tion. Gastric and GIT damage caused by staphylococcal infection were reduced in the Enterococcus gallinarum T71 and bacteriocin-treated groups also dose dependently. We conclude that these bacteriocins may have useful biomedical applications.

Bioavailability of the anti-clostridial bacteriocin thuricin CD in gastrointestinal tract

Thuricin CD is a two component narrow spectrum bacteriocin comprising two peptides with targeted activity against Clostridium difficile. This study examined the bioavailability of thuricin with a view to developing it as an effective antimicrobial against intestinal infection. One of the peptides, Trn-β, was found to be degraded by the gastric enzymes pepsin and α-chymotrypsin both in vitro and in vivo, whereas Trn-α was resistant to digestion by these enzymes and hence was detected in the intestinal porcine digesta following oral ingestion by pigs. In order to determine if spores of the producing organism Bacillus thuringiensis DPC 6431 could be used to deliver the bacteriocin to the gut, spores were fed to 30 mice (approx. 10(8)-2×10(8) per animal) and their germination, growth and production of thuricin in the gastrointestinal tract (GIT) of the animals was monitored. Almost 99 % of the spores delivered to the GIT were excreted in the first 24 h and neither Trn-α nor Trn-β was detected in the gut or faecal samples of the test mice, indicating that ingestion of B. thuringiensis spores may not be a suitable vehicle for the delivery of thuricin CD. When thuricin CD was delivered rectally to mice (n = 40) and C. difficile shedding monitored at 1, 6, 12 and 24 h post-treatment, there was a >95 % (>1.5 log units) reduction of C. difficile 027 in the colon contents of infected mice (n = 10) 1 h post-treatment compared with the control group (n = 10; P<0.001). Furthermore, 6 h post-treatment there was a further 1.5 log reduction in C. difficile numbers (n = 10) relative to the control group (n = 10; P<0.05). These results would suggest that rectal administration of thuricin may be a promising mode of delivery of thuricin CD to the colon.

Safety evaluation of the antimicrobial peptide bovicin HC5 orally administered to a murine model

BACKGROUND

Bovicin HC5 is an antimicrobial peptide that shows a broad spectrum of activity and potential for biotechnological and therapeutic applications. To gain insight about the safety of bovicin HC5 application, the histological and immunostimulatory effects of orally administrated bovicin HC5 to BALB/c mice were evaluated. BALB/c mice were divided into three groups: negative control (NC group); mice given purified bovicin HC5 (Bov group); mice given ovalbumin (positive control, PC group; a murine model of enteropathy). The mice were initially pre-sensitized, and PBS, bovicin HC5 or ovalbumin were administered for 30 days by daily gavages. Histological and morphometric analysis were performed and the relative expression of cytokines was analyzed by real-time RT-PCR.

RESULTS

The oral administration of bovicin HC5 to BALB/c mice reduced weight gain and caused alterations in the small intestine, although absorptive changes have not been detected. The number of total goblet cells and the mucopolysaccharides production were not affected by bovicin HC5 administration. A hypertrophy of Paneth cells and an increase in the number of mitotic cells were observed in Bov group, while the number of mast cells remained unaltered. Increased expression of TNF-α, INF-γ and IL-12 was observed in the small intestine upon bovicin HC5 administration.

CONCLUSION

Bovicin HC5 has only minor effects on intestinal permeability and did not elicit an allergenic response upon oral administration to animal models. Considering the low in vivo toxicity of bovicin HC5, it might be a good candidate for enteral applications.

Investigation of a bacterial pore-forming chimera toxin for application as a novel drug-delivery system tool

BACKGROUND/AIM

Cholesterol-dependent cytolysins (CDCs) are pore-forming toxins from Gram-positive bacteria. The aim of this study was to investigate the potential of a CDC, intermedilysin, as a drug-delivery system (DDS) for clinical application.

MATERIALS AND METHODS

Intermedilysin was modified by the addition of a disulfide bridge to regulate pore formation, by swapping domain 4 to provide cholesterol-binding capacity, and by the introduction of a targeting domain. The resultant chimera protein, His-LTBP-CDC(ss)(IP), was investigated for its use as a DDS tool in vitro.

RESULTS

His-LTBP-CDC(ss)(IP) exhibited a regulated pore-forming capacity under reducing conditions. This chimera protein was able to deliver a drug-carrier liposome specifically to the target cell, to be endocytosed into the cell with subsequent release of the components into the cytoplasm.

CONCLUSION

A chimera protein derived from the bacterial pore-forming toxin intermedilysin (His-LTBP-CDC(ss)(IP)) forms the basis for a novel DDS tool.

Effect of Lactobacillus salivarius bacteriocin Abp118 on the mouse and pig intestinal microbiota

Lactobacilli are Gram-positive bacteria that are a subdominant element in the human gastrointestinal microbiota, and which are commonly used in the food industry. Some lactobacilli are considered probiotic, and have been associated with health benefits. However, there is very little culture-independent information on how consumed probiotic microorganisms might affect the entire intestinal microbiota. We therefore studied the impact of the administration of Lactobacillus salivarius UCC118, a microorganism well characterized for its probiotic properties, on the composition of the intestinal microbiota in two model animals. UCC118 has anti-infective activity due to production of the bacteriocin Abp118, a broad-spectrum class IIb bacteriocin, which we hypothesized could impact the microbiota. Mice and pigs were administered wild-type (WT) L. salivarius UCC118 cells, or a mutant lacking bacteriocin production. The microbiota composition was determined by pyrosequencing of 16S rRNA gene amplicons from faeces. The data show that L. salivarius UCC118 administration had no significant effect on proportions of major phyla comprising the mouse microbiota, whether the strain was producing bacteriocin or not. However, L. salivarius UCC118 WT administration led to a significant decrease in Spirochaetes levels, the third major phylum in the untreated pig microbiota. In both pigs and mice, L. salivarius UCC118 administration had an effect on Firmicutes genus members. This effect was not observed when the mutant strain was administered, and was thus associated with bacteriocin production. Surprisingly, in both models, L. salivarius UCC118 administration and production of Abp118 had an effect on Gram-negative microorganisms, even though Abp118 is normally not active in vitro against this group of microorganisms. Thus L. salivarius UCC118 administration has a significant but subtle impact on mouse and pig microbiota, by a mechanism that seems at least partially bacteriocin-dependent.

Effects of albusin B (a bacteriocin) of Ruminococcus albus 7 expressed by yeast on growth performance and intestinal absorption of broiler chickens--its potential role as an alternative to feed antibiotics

BACKGROUND

Bacteriocins with antimicrobial activity are considered as potential alternatives to antibiotics. The aim of this study was to investigate the effect of albusin B (bacteriocin) of Ruminococcus albus 7 expressed by yeast on the growth performance of broiler chickens. Ninety 1-day-old healthy broiler chickens were randomly divided into three groups: control, albusin B (2.5 g kg(-1)) and nosiheptide (2.5 mg kg(-1), antibiotic control). Growth performance and intestinal functions were measured at 5 weeks of age.

RESULTS

Albusin B-supplemented broilers showed increased body weight gain compared with control broilers (54.7 ± 5.3 vs 48.5 ± 6.1 g day(-1) per bird, P < 0.05). Broilers supplemented with nosiheptide had a less developed mucosal layer than broilers in the other two groups. Compared with the control group, broilers supplemented with albusin B or nosiheptide showed increased mRNA expression of sGLT1, GLUT2 and PEPT1 in the jejunum (P < 0.05). The faecal Lactobacillus count was higher in the albusin B group than in the other two groups (P < 0.05).

CONCLUSION

Albusin B supplementation increased intestinal absorption and elevated the faecal Lactobacillus count, thereby promoting the growth performance of broiler chickens. These improvements resulting from albusin B supplementation provide evidence of potential alternatives to antibiotics in broiler chicken feed.

[Efficacy of enterocin S760 in treatment of mice with anthrax infection due to Bacillus anthracis M-71]

The therapeutic efficacy of enterocin S760, a broad spectrum antimicrobial peptide produced by Enterococcus faecium LWP760 was tested on mice infected with Bacillus anthracis M-71 to induce anthrax (second Tsenkovsky's vaccine). Intraperitoneal four-, two- or one-fold administration of the peptide in a dose of 25 mg/kg for 10 days for prophylactic (1 hour after the contamination) and therapeutic (24 hours after the contamination) purposes prevented or cured the infection in 90-100% of the mice versus the 100-percent lethality in the control (untreated animals). The antimicrobial activity of enterocin S760 against B. anthracis M-71 in vivo correlated with activity in vitro. Enterocin S760 is considered a novel promising antimicrobial for the treatment of grampositive and gramnegative infections.

[Use of enterocin S760 for prevention and treatment of experimental Salmonella infection in mice]

AIM

To demonstrate treatment efficacy of bacteriocin S760 synthesized by Enterococcus faecium 760 for septic Salmonella infection in mice.

MATERIALS AND METHODS

One hundred mice, which were intraperitoneally inoculated with 100 LD50 of Salmonella enteritidis strain 92 Rif(r), received bacteriocin 1 hour (prevention) or 48 hours (treatment) after inoculation in doses 25, 50, or 100 mg/kg every 6 hours during 5 or 10 days.

RESULTS

Use of peptide S760 for prophylaxis in dose 50 mg/kg during 10 days prevented lethal infection in 100% of animals, whereas its use for treatment cured 70% of animals with generalized salmonellosis. Shortening of treatment course from 10 to 5 days and reducing dose of bacteriocin led to less pronounced treatment effect but in all animals it was expressed by increase of mean length of life compared to control (not treated).

CONCLUSION

Obtained results demonstrated high treatment efficacy of bacteriocin S760 during septic salmonellosis and perspectives of its use in medicine and animal health.

Microbial antagonists to food-borne pathogens and biocontrol

Application of natural antimicrobial substances (such as bacteriocins) combined with novel technologies provides new opportunities for the control of pathogenic bacteria, improving food safety and quality. Bacteriocin-activated films and/or in combination with food processing technologies (high-hydrostatic pressure, high-pressure homogenization, in-package pasteurization, food irradiation, pulsed electric fields, or pulsed light) may increase microbial inactivation and avoid food cross-contamination. Bacteriocin variants developed by genetic engineering and novel bacteriocins with broader inhibitory spectra offer new biotechnological opportunities. In-farm application of bacteriocins, bacterial protective cultures, or bacteriophages, can decrease the incidence of food-borne pathogens in livestock, animal products and fresh produce items, reducing the risks for transmission through the food chain. Biocontrol of fungi, parasitic protozoa and viruses is still a pending issue.

Bacteriocin production as a mechanism for the antiinfective activity of Lactobacillus salivarius UCC118

The mechanisms by which probiotic strains enhance the health of the host remain largely uncharacterized. Here we demonstrate that Lactobacillus salivarius UCC118, a recently sequenced and genetically tractable probiotic strain of human origin, produces a bacteriocin in vivo that can significantly protect mice against infection with the invasive foodborne pathogen Listeria monocytogenes. A stable mutant of Lb. salivarius UCC118 that is unable to produce the Abp118 bacteriocin also failed to protect mice against infection with two strains of L. monocytogenes, EGDe and LO28, confirming that bacteriocin production is the primary mediator of protection against this organism. Furthermore, Lb. salivarius UCC118 did not offer any protection when mice were infected with a strain of L. monocytogenes expressing the cognate Abp118 immunity protein AbpIM, confirming that the antimicrobial effect is a result of direct antagonism between Lb. salivarius and the pathogen, mediated by the bacteriocin Abp118.

Antimycobacterial activity of bacteriocins and their complexes with liposomes

OBJECTIVES

Bacteriocins (Bcn) are natural peptides that are secreted by several taxonomically distant bacteria and exert bactericidal activity against other bacterial species. Their capacity to inhibit growth of virulent Mycobacterium tuberculosis H37Rv was evaluated in this study.

METHODS

Five different Bcn were isolated and purified from bacterial culture supernatants, their amino acid sequence was determined, and activity against mycobacteria assessed in three different models: in vitro mycobacterial cultures, in vitro infection of mouse macrophages and in vivo high-dose infection of inbred mice.

RESULTS

In the in vitro model, four out of five Bcn exhibited stronger antimycobacterial activity than equal concentrations of a widely used anti-TB antibiotic, rifampicin. These Bcn were non-toxic for mouse macrophages at a concentration of 0.1 mg/L (>MIC(90) of these compounds). Pure Bcn did not inhibit mycobacterial growth within murine macrophages when added at 0.01-0.1 mg/L, suggesting that at physiologically tolerable concentrations these molecules do not penetrate through the membrane of eukaryotic cells. However, when administered as a complex with phosphatidylcholine-cardiolipin liposomes, Bcn5 (selected as a model compound due to its cytotoxicity and antimycobacterial activity regular titration curves) demonstrated capacity both to inhibit intracellular growth of M. tuberculosis and to prolong survival of mice in an acute TB model.

CONCLUSIONS

Given that the mechanism of Bcn bactericidal activity differs from that of all commonly used antibiotics, their possible involvement in complex TB therapies deserves further study.

Two subpopulations of Listeria monocytogenes occur at subinhibitory concentrations of leucocin 4010 and nisin

In situ analyses of single Listeria monocytogenes cells at subinhibitory concentrations of leucocin 4010 and nisin revealed two subpopulations when measured by fluorescence ratio imaging microscopy (FRIM) after staining with 5(6)-carboxyfluorescein diacetate succinimidyl ester. One subpopulation consisted of cells with a dissipated pH gradient (DeltapH), and the other consisted of cells that maintained DeltapH. The proportion of cells belonging to each subpopulation was estimated, and the concentrations of bacteriocins required to dissipate DeltapH for 90% of the cell population (ED90) was predicted. ED90 increased after the addition of sodium chloride (1 to 3% [wt/vol]) to the bacteriocin solutions, while ED90 decreased by the addition of sodium nitrite (60 and 100 ppm). Other meat additives, including sodium phosphate, sodium lactate, sodium citrate, and sodium acetate slightly increased ED90. The inhibitory effect of sodium chloride on the antilisterial activity of leucocin 4010 and nisin was confirmed on the surfaces of meat sausages. This study highlights the important practical implications of applying subinhibitory concentrations of bacteriocins, which results in unaffected target cells. In situ analyses by FRIM in combination with modeling of single-cell data can be applied to ensure that sufficient concentrations of bacteriocins are used in food preservation.

In vivo activity of mutacin B-Ny266

OBJECTIVES

The objective of this study was to assess the in vivo activity of mutacin B-Ny266 (a bacteriocin produced by Streptococcus mutans) in order to eventually use it as an antibiotic.

METHODS

Intraperitoneal infection was induced with a methicillin-susceptible Staphylococcus aureus strain in mice. Some of the mice were simultaneously injected intraperitoneally with mutacin B-Ny266, some with the vehicle only and some with vancomycin.

RESULTS

While there was 70 and 100% mortality in the control groups of mice, no mortality was observed in the mice injected with vancomycin or mutacin B-Ny266.

CONCLUSIONS

The results presented here show, for the first time, the in vivo efficacy of a mutacin (B-Ny266) against an experimental intraperitoneal infection by S. aureus in a mouse model.

Bacteriocin Serratine-P as a biological tool in the control of fire blight Erwinia amylovora

Fire blight, caused by the bacterium Erwinia amylovora (Burill Winslow et al.), is the most important bacterial disease in European pear growing. It can cause a lot of damage in some countries on apple and on pear trees in orchards and also in the fruit tree nurseries. In Belgium, the disease is present since 1972. Control of fire blight in Belgian fruit orchards is made on a broad basis of measurements in and around the fruit trees. The use of an antibiotic is allowed for application only during the primary blossom period under strict controlled regulations. The use of antobiotics in agriculture is strongly discussed on the European level today and will probably disappear in the near future. Therefore, the research on fire blight control concentrates on the possibilities of biological control with antagonistic bacteria such as Pantoea agglomerans (Erwinia herbicola), Bacillus subtilis or Pseudomonas syringae strain A 506. The use of Serratine-P, a phage tail-like bacteriocin, produced by Serratia plymiticum, shows an interesting antibacterial activity against Erwinia amylovora. Its mode of action consists in the perforation of the cytoplasmic membrane of the target cell, inducing perturbations in cellular exchanges and a final lysis of the bacterial cell. In this paper some trials are discussed on the use of Serratine-P at different doses and on different infection types on pear trees. The results indicate interesting protection possibilities on blossom- and fruit infections.

Considerations relating to the epidemiology of human immunodeficiency virus infection: the impact of bacterial antigens and consequences for treatment

OBJECTIVE

A treatment for patients with human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) is presented, which is based on an isopathic method that appears to be effective in eliminating bacterial antigens from the body. The concept is based on a new hypothesis concerning the outbreak and spread of AIDS in Africa and worldwide.

SUBJECTS AND DESIGN

Laboratory data are presented from five European and seven African patients with HIV.

RESULTS

Oral administration of ultra-low doses of a lysate of Staphylococcus aureus Cowan I (12c potency) resulted in a significant increase of CD4 T-cell subsets and CD4/CD8 ratios in patients with HIV infection as well as in advanced stages of HIV disease, concomitant with the improvement of clinical HIV-related symptoms.

CONCLUSIONS

Based on epidemiologic data, the beginning of the African AIDS epidemic is related-to time, place, and circumstances-to the initial large-scale introduction of antibiotics in areas of Central Africa that would later comprise the AIDS belt. It is concluded that certain antimicrobial agents can enhance the formation of persistent bacterial superantigens, which may indicate a link between asymptomatic HIV carriers and the development of AIDS. According to this view, superantigens and bacterial cell wall components remaining in the body after antibiotic treatment cause a permanent activation of the immune system and would thus favor T-cell infection and viral replication in HIV-infected individuals.

[Early jejunal nutrition with combined pre- and probiotics in acute pancreatitis--prospective, randomized, double-blind investigations]

BACKGROUND

Development of infection of pancreatic tissue in patients with severe acute pancreatitis dramatically increases morbidity and mortality. Colonisation of the lower gastrointestinal tract and oropharynx, mostly with gram-negative but sometimes also gram-positive bacteria is known to precede the contamination of the pancreatic tissue by a few days. A few specific lactic acid bacteria such as Lactobacillus plantarum 299 were effective in preventing colonisation of the gut by potential pathogens, to reduce endotoxemia and to stimulate the gut-associated lymphatic system (GALT) and the immune system.

METHODS

Patients with acute pancreatitis, arriving within 48 hours after onset of disease showing typical clinical picture and laboratory signs of pancreatitis (plasma amylase > 200 U/l, CRP > 150 mg/l and an Imrie-score = or > 3) were randomised into two groups During the first week the treatment group received a freeze-dried preparation containing 10(9) live Lactobacillus plantarum 299 together with an oat fibre substrate. The control group received a similar preparation, but the Lactobacillus plantarum 299 had been inactivated by heat. For seven days the treatment was repeated twice every day. The preparations were delivered to the hospital in sachets so the content was unknown to the investigators, staff and patients.

RESULTS

Forty five patients completed the study before there was indication that one group differed from the other in a statistically significant way, at which time the study was discontinued and the code broken. At this time 22 patients had received treatment with live and 23 patients with heat-killed Lactobacillus plantarum 299. Infected necrosis and abscesses occurred in 1/22 (4.5%) in the treatment group vs. 7/23 (30%) (p = 0.023) in the control group. The length of stay was 13.7 days in the treatment group vs. 21.4 days in the control group (not statistically significant).

CONCLUSIONS

Supplementing Lactobacillus plantarum 299 is an effective tool to prevent pancreatic sepsis, to reduce the number of operations and length of stay. The only patient who developed sepsis in the treatment group did so eight days after the treatment had been discontinued. One week treatment, as in the present study, is too short. It should be provided for at least 2 weeks, or more appropriately, as long as the patients are treated with antibiotics or have signs of GI colonisation.

Expression of a crown gall biological control phenotype in an avirulent strain of Agrobacterium vitis by addition of the trifolitoxin production and resistance genes

BACKGROUND

Agrobacterium vitis is a causal agent of crown-gall disease. Trifolitoxin (TFX) is a peptide antibiotic active only against members of a specific group of alpha-proteobacteria that includes Agrobacterium and its close relatives. The ability of TFX production by an avirulent strain of Agrobacterium to reduce crown gall disease is examined here.

RESULTS

TFX was shown to be inhibitory in vitro against several A. vitis strains. TFX production, expressed from the stable plasmid pT2TFXK, conferred biological control activity to an avirulent strain of A. vitis. F2/5, against three virulent, TFX-sensitive strains of A. vitis tested on Nicotiana glauca. F2/5(pT2TFXK) is significantly reduces number and size of galls when co-inoculated with tumorigenic strain CG78 at a 10:1 ratio, but is ineffective at 1:1 or 1:10 ratios. F2/5(pT2TFXK) is effective when co-inoculated with tumorigenic strain CG435 at 10:1 and 1:1 ratios, but not at a 1:10 ratio. When F2/5(pT2TFXK) is co-inoculated with CG49 at a 10:1 ratio, the incidence of gall formation does not decline but gall size decreases by more than 70%. A 24 h pre-inoculation with F2/5(pT2TFXK) does not improve biological control at the 1:10 ratio.

CONCLUSIONS

TFX production by an avirulent strain of Agrobacterium does confer in that strain the ability to control crown gall disease on Nicotiana glauca. This is the first demonstration that the production of a ribosomally synthesized, post-translationally modified peptide antibiotic can confer reduction in plant disease incidence from a bacterial pathogen.

Preoperative oral application of immunoglobulin-enriched colostrum milk and mediator response during abdominal surgery

Our objective was to evaluate the influence of pre-operative oral application of an immunoglobulin-enriched milk preparation on endotoxin translocation and mediator release during and after abdominal surgery. Forty patients who had been treated by partial (n = 4) or total gastrectomy (n = 8) or pancreatic resection (n = 28) were enrolled in a placebo-controlled pilot study. Pre-operatively, patients were randomly treated for 3 days by oral application of a bovine milk preparation (lactobin 56g/day, n = 20) or placebo (n = 20). In both groups, endotoxin translocation and mediator release was studied pre- and intraoperatively by measuring endotoxin, endotoxin-neutralizing capacity (ENC), interleukin 6, C-reactive protein, transferrin, alpha-2-macroglobulin, albumin, apoliprotein-A1/-B, IgG, IgA, and IgM. The clinical course was followed up by daily evaluation of the Apache-II-score. Clinical data were comparable in both groups. The lactobin group showed significantly lower levels of endotoxin and ENC compared to the placebo group. Acute phase response, endotoxin-binding proteins, and clinical outcome did not differ between both groups. We conclude that prophylactic oral application of lactobin reduces perioperative endotoxemia and prevents reduction of ENC, suggesting a stabilization of gut barrier during abdominal surgery.

[Local application of eubiotics in the combined treatment of purulent wounds of the maxillofacial area]

The efficiency of eubiotics (bifidumbacterin-forte and lactobacterin, Partner Firm) in local treatment of suppurative wounds was studied in a microbiological experiment and in a clinical setting. As antagonists of Staphylococcus aureus and S. epidermidis, saprophytes suppress their growth in vitro. Clinical use of these drugs accelerated the treatment of patients with pyoinflammatory maxillofacial diseases.

Evaluation of lacticin 3147 and a teat seal containing this bacteriocin for inhibition of mastitis pathogens

Lacticin 3147 is a broad-spectrum bacteriocin produced by Lactococcus lactis subsp. lactis DPC3147 which is bactericidal against a range of mastitis-causing streptococci and staphylococci. In this study, both lacticin 3147 and the lantibiotic nisin were separately incorporated into an intramammary teat seal product. The seal containing lacticin 3147 exhibited excellent antimicrobial activity and might form the basis of an improved treatment for the prevention of mastitis in dry cows.

Antilisterial activity of pediocin AcH in model food systems in the presence of an emulsifier or encapsulated within liposomes

The listericidal activity of pediocin AcH was evaluated in slurries (5, 10, or 25% in dH2O) of nonfat dry milk, butterfat, beef muscle tissue, or beef tallow. Slurries were inoculated with Listeria monocytogenes (2-strain mixture; 2.5 x 10(6) cfu/ml) and then with pediocin AcH (30,000 arbitrary units (AU) per ml of slurry). Although pediocin activity was reduced in slurries, sufficient pediocin remained to decrease the listeriae population. For all slurries tested, the greatest decrease in counts of Listeria (1.2-1.8 log10 cfu decrease) and decrease in pediocin activity (12-54% recovery of original activity) occurred within 1.5 min of addition of pediocin to slurries. Thereafter, counts of Listeria did not change appreciably, but pediocin activity continued to decrease in most treatments for up to 60 min. In general, greater activity was recovered from: (i) slurries of lower (5%) compared to higher (25%) concentrations of food; and (ii) dairy- compared to meat-based slurries. Next, pediocin AcH was encapsulated within phosphatidyl-choline-based liposomes before addition to slurries (10%), or was used unencapsulated in slurries (10%) containing the emulsifier Tween 80. Greater pediocin activity (29-62% increase; average over all concentrations) was recovered from slurries containing encapsulated compared to free pediocin AcH. Likewise, greater pediocin activity was recovered from slurries containing an emulsifier (4-90% increase; average over all concentrations) compared to otherwise similar slurries without Tween 80. The additional recovery of pediocin activity afforded by liposomes or Tween 80 underscores the potential for direct application of biopreservatives to provide another hurdle for L. monocytogenes in foods.

[Treatment of chronic rhinitis in children]

This paper discusses involvement of intestinal dysbacteriosis in nasal inflammation. Altogether 42 children of preschool age with chronic rhinitis were examined. It was found that microbial changes in the nasal cavity were related to the degree of intestinal dysbacteriosis, which was detected in most patients. The drugs that were used in combined therapy to treat microbial changes in the nasal mucosa and intestine produced good clinical and bacteriological effects. The 4 month follow-up showed that the children on the combined therapeutic protocol remained in the remission stage throughout this time period, whereas 85 +/- 10% of the control children exhibited exacerbation of the inflammatory process in the nasal cavity within 2-3 weeks after onset of standard treatment.

Effect of mutacin administration on Streptococcus mutans-induced dental caries in rats

A bacteriocin from serotype c Streptococcus mutans strain C3603 was examined for its inhibitory effect on experimental dental caries in rats infected with S. mutans MT8148R (serotype c). Significant reduction in the incidence of dental caries was found only when bacteriocin was incorporated both in the drinking water and in the diet at a high concentration. However, caries reduction was not as great as expected and the addition of bacteriocin to drinking water alone had no effect on the recovery of S. mutans, plaque deposition or caries incidence. The bacteriocin activity must have been reduced in the oral cavity of rats, and the reasons were examined. Bacteriocin-resistant mutants were not detected and the bacteriocin was not inactivated by saliva. Whereas the bacteriocin did not kill the S. mutans cells grown in a sucrose-containing medium, it completely killed the cells grown in a sucrose-free medium.