Role of Lipoteichoic Acid from the Genus Apilactobacillus in Inducing a Strong IgA Response.

Lactic acid bacterium-containing fermentates provide beneficial health effects by regulating the immune response. A naturally fermented vegetable beverage, a traditional Japanese food, reportedly provides health benefits; however, the beneficial function of its bacteria has not been clarified. Apilactobacillus kosoi is the predominant lactic acid bacterium in the beverage. Using murine Peyer's patch cells, we compared the immunoglobulin A (IgA)-inducing activity of A. kosoi 10HT to those of 29 other species of lactic acid bacteria and found that species belonging to the genus Apilactobacillus (A. kosoi 10HT, A. apinorum JCM30765T, and A. kunkeei JCM16173T) possessed significantly higher activity than the others. Thereafter, lipoteichoic acids (LTAs), important immunostimulatory molecules of Gram-positive bacteria, were purified from the three Apilactobacillus species, and their IgA-inducing activity was compared to those of LTAs from Lactiplantibacillus plantarum JCM1149T and a probiotic strain, Lacticaseibacillus rhamnosus GG. The results revealed that LTAs from Apilactobacillus species had significantly higher activity than others. We also compared the LTA structure of A. kosoi 10HT with that of L. plantarum JCM1149T and L. rhamnosus GG. Although d-alanine or both d-alanine and carbohydrate residues were substituents of free hydroxyl groups in the polyglycerol phosphate structure in LTAs from strains JCM1149T and GG, d-alanine residues were not found in LTA from strain 10HT by 1H nuclear magnetic resonance (NMR) analysis. Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) analysis of the glycolipid structure of LTA revealed that LTA from strain 10HT contained dihexosyl glycerol, whereas trihexosyl glycerol was detected in LTAs from other strains. These structural differences may be related to differences in IgA-inducing activity. IMPORTANCE The components of lactic acid bacteria that exert immunostimulatory effects are of increasing interest for therapeutic and prophylactic options, such as alternatives to antibiotics, cognitive enhancements, and vaccine adjuvants. LTAs act as immunostimulatory molecules in the host innate immune system by interacting with pattern recognition receptors. However, as LTA structures differ among species, detailed knowledge of the structure-function relationship for immunostimulatory effects is required. Comparisons of the IgA-inducing activity of LTAs have demonstrated that LTAs from the genus Apilactobacillus possess distinctive activities to stimulate mucosal immunity. The first analysis of the LTA structure from the genus Apilactobacillus suggests that it differs from structures of LTAs of related species of lactic acid bacteria. This knowledge is expected to aid in the development of functional foods containing lactic acid bacteria and pharmaceutical applications of immunostimulatory molecules from lactic acid bacteria.

Administration of Enterococcus faecium HS-08 increases intestinal acetate and induces immunoglobulin A secretion in mice.

A probiotic is considered a live microbial feed supplement that has beneficial effects on the host. In this study, the probiotic property by which Enterococcus faecium HS-08 strengthens the immune system was investigated. Using a murine model, we evaluated the abilities of this strain to increase intestinal short-chain fatty acid contents and to induce the production of mucosal immunoglobulin A (IgA), which are crucial for mucosal immune systems. Various amounts (0%, 0.0038%, 0.038%, or 0.38%) of strain HS-08 cells were administered to BALB/cAJcl mice, which resulted in a dose-dependent increase of fecal IgA levels. A qRT-PCR analysis of Peyer's patch cells revealed that the gene expression of retinal-dehydrogenase, interleukin 6, B-cell-activating factor, and a proliferation-inducing ligand were increased, which leads to IgA secretion via a T-cell-independent mechanism. The administration of 0.038% and 0.38% of strain HS-08 cells also increased fecal acetate levels, which plays an important role for maintaining immune functions. This cecal floral analysis and the stability of strain HS-08 against gastrointestinal digestion suggest that this strain can inhabit the host intestine. In conclusion, the administration of E. faecium HS-08 increased intestinal acetate levels and enhanced IgA secretion, which may result in strengthening of the mucosal immune system.

Immunostimulatory effect on dendritic cells of the adjuvant-active exopolysaccharide from Leuconostoc mesenteroides strain NTM048.

This study evaluated the immunostimulative effect on bone marrow-derived dendritic cells (DCs) of adjuvant-active exopolysaccharide (EPS) produced by Leuconostoc mesenteroides strain NTM048. EPS stimulation increased IL-6, IL-10, IL-12, and retinal dehydrogenase (RALDH) gene expression levels and induced retinoic acid-synthesizing RALDH-active DCs, which play a crucially important role in controlling adaptive immune responses in mucosa.

[Influences of %T>MIC achievement probability due to the difference of the MIC measurement concentration range-analysis of meropenem for Pseudomonas aeruginosa-].

We attempted to analyze any influences to %T>MIC achievement probability due to the difference of the MIC measurement concentration range of MEPM for 613 strains of Pseudomonas aeruginosa by the Monte Carlo simulation method. As for the analysis, we calculated the achievement probability of 30% and 50% for MEPM %T>MIC by the administration volume of MEPM: 250 mg, 500 mg, and 1,000 mg, the administration time: 0.5 h, and 3 h, the administration frequency: 2 times, and 3 times, and the renal excretion capability: Normal, Slight, Moderate, and High abnormal with the 3 types of MIC concentration measurement level 1) <=0.06~>=256 µg/ml: 13 levels, 2) <=0.5~>=32 µg/ml: 7 levels, and 3) <=1~>=16 µg/ml: 5 levels. As the result, we found the following findings; 1. In terms of the administration of normal renal excretion capability, 250 mg, in comparison with 500 mg and 1,000 mg, indicated the differential due to the difference of MIC measurement concentration range. 2. The administration volume of MEPM 500 mg which has been recommended shown the less differential of the achievement probability due to the difference of MIC measurement concentration range. As the renal excretion was shifted through Normal to Slight to Moderate to High abnormal, the differential of the achievement probability due to the difference of MIC measurement concentration range was gradually decreased. With these results, PK/PD analysis is possible for the 5 levels measurement concentration. It is significant that the facility using the automated microbiology analyzer can provide not only the MIC report, but also the information on the appropriate administration method for antibacterial drug by PK/PD analysis.

Enzymatically synthesized exopolysaccharide of a probiotic strain Leuconostoc mesenteroides NTM048 shows adjuvant activity to promote IgA antibody responses.

Leuconostoc mesenteroides strain NTM048 produces an exopolysaccharide (EPS; glucose polymers 94% and fructose polymers 6%) with adjuvanticity for mucosal vaccination. Strain NTM048 includes three putative EPS-synthesizing genes, gtf1 and gtf2 for synthesizing glucose polymers, and lvnS for synthesizing fructose polymer. To elucidate the key polymer structure for adjuvanticity, two genes, gtf1 and gtf2, which were annotated as glycoside hydrolase family 70 enzyme genes, were expressed in Escherichia coli. Glycosyl-linkage composition analysis and NMR analysis showed that the recombinant enzyme Gtf1 produced a soluble form of α-1,6-glucan, whereas the recombinant enzyme Gtf2 produced glucans with approximately equal percentages of α-1,6- and α-1,3-glucose residues both in the supernatant (S-glucan) and as a precipitate (P-glucan). Comparison of polysaccharides synthesized by Gtf1, Gtf2, and LvnS revealed that Gtf2-S-glucan, which was produced in the supernatant by Gtf2 and formed particles of 7.8 µm, possessed 1.8-fold higher ability to stimulate IgA production from murine Peyer's patch cells than native NTM048 EPS. Evaluation of adjuvanticity by intranasal administration of mice with an antigen (ovalbumin) and Gtf2-S-glucan or NTM048 EPS showed that Gtf2-S-glucan induced the production of higher antigen-specific antibodies in the airway mucosa and plasma, suggesting a pivotal role of Gtf2-S-glucan in the adjuvanticity of NTM048 EPS.

[Evaluation of rapid antimicrobial susceptibility test for Staphylococcus aureus by chemiluminescent assay and its application for screening of beta-lactam antibiotic induced vancomycin-resistant MRSA].

Minimum inhibitory concentrations (MICs) of vancomycin (VCM) and teicoplanin (TEIC) were measured using a novel susceptibility test based on the chemiluminescence assay method (CA) (Rapid-Lumi Eiken; Eiken Chemicals, Tokyo, Japan) against 84 strains of Staphylococcus aureus, consisting of 82 strains of methicillin-resistant S. aureus (MRSA) from clinical isolated, S. aureus Mu3 involving beta-lactam antibiotic induced vancomycin (VCM) resistant MRSA (BIVR) and methicillin-susceptible S. aureus ATCC 29213. The results were in good accordance with the values determined by Clinical and Laboratory Standards Institute (CLSI): i.e., 100% (84/84) of consistency for VCM and 95% (80/84) for TEIC, respectively. In addition, BIVR strains were properly estimated from the results of the CA method and using the BIVR detection method with Mu3 agar (Mu3 Agar method), even though the incubation times was very short (2-4 h). In conclusion, it was found that the new method is reliable and rapid to detect BIVR strains in clinical laboratories.

A chromogenic substrate culture plate for early identification of Vibrio vulnificus and isolation of other marine Vibrios.

Vibrio vulnificus infection can result in necrotizing fasciitis and sepsis, which have short latentcy periods and high mortality rates. Thus, an easy and quick detection method is needed to improve the outcome. To distinguish V. vulnificus from other pathogens that cause necrotizing fasciitis, we developed a selective isolation culture agar plate (Chromochecker Vibrio Agar-1; CVA-1) for use in environmental monitoring and in the clinical setting. One hundred four strains of V. vulnificus, already identified biochemically, showed typical colony form and color when grown on CVA-1. Thirty-six of 51 marine bacteria samples suspected to be V. vulnificus on CVA-1 were subsequently identified as V. vulnificus by a biochemical identification system. Of 8 bacteria known to cause necrotizing fasciitis, only V. vulnificus grew on CVA-1. In addition, growth on CVA-1 allowed ready differentiation of Vibrio species. CVA-1 can be used to distinguish pathogenic Vibrios according to colony form and chromatic differences.

Moraxella catarrhalis bacteraemia associated with prosthetic vascular graft infection.

Moraxella catarrhalis, formerly called Branhamella catarrhalis, 'Neisseria catarrhalis' or 'Micrococcus catarrhalis', is a Gram-negative, aerobic diplococcus frequently found as a colonizer of the upper respiratory tract. Over the last 20-30 years, this bacterium has emerged as a genuine pathogen, and is now considered an important cause of otitis media in children and an aetiological agent in pneumonia in adults with chronic obstructive pulmonary disease. However, bacteraemia due to M. catarrhalis has rarely been reported. Presented here is a case of M. catarrhalis bacteraemia associated with prosthetic vascular graft infection along with a review of the relevant literature.