Previously, we isolated and examined a bacterial strain designated as TM-I-3, belonging to the genus Bacillus, from soil in Nagasaki, Japan. This bacterium was able to inhibit the growth of molds, without coming into direct contact with them. Non-contact antifungals are capable of providing multidirectional inhibition and may contribute to disease prevention. In this study, we revealed the bacteriological properties of TM-I-3 and evaluated the antifungal activity of the compounds emitted from this bacterium. In addition, we analyzed the antimicrobial substances released from TM-I-3 using GC/MS to elucidate the mechanism of its action. Antimicrobial compounds from strain TM-I-3 were identified as acetic acid, propanoic acid, isovaleric acid, 2-methylbutanoic acid, and benzaldehyde, which are all reported to have antimicrobial activity. TM-I-3 demonstrated possible efficacy in inhibiting the growth of Aspergillus fumigatus, Cladosporium cladosporioides and Penicillium expansum, which may lead to inhibition of common fungal contaminants of household products and prevention of some pulmonary diseases.

Role of Trichoderma species is well documented as antagonists as well as plant growth enhancers. Presently, the fungicidal potential of three Trichoderma species namely, T. koningii (FCBP769) , T. viride (FCBP904) , and T. harzianum (FCBP1277) was assessed against Alternaria alternata that causes leaf necrotic spots of Syzygium cumini and broad range of other plants using 0, 15, 30, 45, 60 and 75% dilutions of filtrates. There was a significant reduction of around 40-95%, 22-86% and 52-91% in fungal biomass by T. koningii, T. viride and T. harzianum, respectively. In fractionation bioassays, Trichoderma metabolites were partitioned using organic solvents viz., n-butanol, n-hexane, chloroform and ethyl acetate. Antifungal activity at different concentrations (10, 20, 30, 40 and 50 ppm) was assessed against the pathogen. Ethyl acetate fraction of T. koningii extract displayed the most promising activity resulting in 10-90% suppression in biomass. In case of T. viride butanol fraction proved the most effective in retarding the growth of pathogen from 20 to 80%. While T. harzianum extract revealed 55-85% arrest in fungal biomass due to n-hexane fraction. Present study concludes that test Trichoderma species demonstrated a strong fungicidal activity against A. alternata. Current research offers the possibility of developing strategies for controlling pathogens with bioactive metabolites of Trichoderma.

This study was to survey the capturing rate in Japanese dental clinics of the Lasioderma serricorne (cigarette beetles) , and to evaluate the beetle's potential as a carrier for transmission of nosocomial pathogens. L. serricorne imagoes were captured in pheromone traps in 14 Japanese dental clinics in August and September 2012 and 2013, and their numbers recorded. Polymerase chain reaction (PCR) for the bacterial antibiotic-resistant genes mecA, vanA, vanB, blaIMP, and blaVIM was performed on the captured L. serricorne imagoes. Bacterial species in the captured specimens were identified by 16S rRNA PCR and sequencing analysis. The L. serricorne imagoes were captured from 10 dental clinics (71.4%) . We failed to detect the presence of nosocomial antibiotic-resistant pathogens in L. serricorne imagoes. The bacterial species detected most commonly in the imagoes was Wolbachia sp., an intracellular proteobacterium infecting certain insect species. Monitoring of insects including L. serricorne should be incorporated into regiment of the infection control.

The prevalence of antibiotic resistant bacteria in aquaculture has reached alarming proportions and intensified the search for microbe derived antimicrobial compounds. This study isolated bacteria from the intestine of Sagor catfish (Hexanematichthys sagor) and screened it for antagonistic properties. Five out of 334 bacterial isolates inhibited growth of fish pathogens. The 5 bacterial strains included relatives of Shewanella haliotis, Myroides odoratimimus, Vibrio harveyi, Vibrio alginolyticus and Alcaligenes faecalis. The growth profiles and probiotic properties of these bacteria were examined. The results showed that the isolate 9 (3) 7.5.2.1, whose closest relative was S. haliotis exhibited growth and probiotic advantage compared to the other bacterial strains, such as highest doubling time and the ability to survive at all experimental temperatures (18 to 60℃) , and bile concentrations (0.01 to 1.00%) and pH (pH2 to 9) . While the bacteria with probiotic properties were successfully isolated. Further study is necessary to examine the efficiency of the probiotic candidate bacteria in boosting fish immunity against pathogens.

The commercially available 3 types of selective media in Japan were compared for the detection of Bacillus cereus. When assessed inclusivity using 25 B. cereus strains, MYP agar, NGKG agar, and chromogenic X-BC agar demonstrated excellent inclusivity. For exclusivity study using 50 non-B. cereus strains, MYP, NGKG, and X-BC allowed to grow 11, 7, and 3 strains, respectively. Of the grown bacteria on each strains tested, only 2 strains of B. thuringiensis formed typical B. cereus colonies on all selective media tested. The NGKG and X-BC were compared with MYP as a reference using artificially contaminated food (fried rice, plain rice, fried noodle, and potato salad ), since MYP is recommended in ISO 7932: 2004. The both correlation coefficients between NGKG and MYP, and X-BC and MYP were 0.999. Therefore, we demonstrated that NGKG and X-BC can be adapted to ISO 7932: 2004 method for selected food as well as MYP.

The four types of chromogenic selective media that are commercially available in Japan were compared for establishing a Japanese standard method for detecting Cronobacter spp. based on ISO/TS 22964:2006. When assessed using 9 standard Cronobacter spp. strains and 29 non-Cronobacter strains, Enterobacter sakazakii isolation agar, ChromocultTM Enterobacter sakazakii agar, CHROMagarTM E. sakazakii, and XM-sakazakii agar demonstrated excellent inclusivity and exclusivity. Using the ISO/TS 22964:2006 method, the recovered numbers of 38 Cronobacter spp. strains, including 29 C. sakazakii isolates obtained from each medium, were equivalent, indicating that there was no significant difference (p > 0.05) among the four types of chromogenic selective media. Thus, we demonstrated that these four chromogenic selective media are suitable alternatives when using the standard method for detecting Cronobacter spp. in Japan, based on the ISO/TS 22964:2006.

In this study, antibacterial polyelectrolyte/silver nanoparticle (Ag NP) composite powder was mixed with epoxy resins as fillers to impart antibacterial activity. Either an anhydride-type or a polyamideamine-type curing agent was applied to a bisphenol A-type base compound to prepare the epoxy resins. Antibacterial assays of these resins against Escherichia coli were performed using the shake tube technique; suppression of antibacterial activity was found for the anhydride-type resin, although the polyamideamine-type resin did exhibit antibacterial activity. The anhydride-type resin is considered to have suppressed antibacterial activity because carboxylate ions derived from unreacted anhydride in aqueous medium can induce chemical adsorption of silver ions and/or charge repulsion of E. coli.

Malodorants in the human axilla are produced from human biogenic precursors by axillary bacterial enzymes. In the present study, we used pyrosequencing analysis to identify the axillary bacterial microbiota of 13 Japanese male subjects with cumin-like, spicy body odor (C type), and 9 with milky, skin-based body odor (M type). Anaerococcus, Corynebacterium, and Staphylococcus predominated in both C- and M-type subjects, followed by Moraxella and Peptoniphilus. These genera accounted for 96.2-99.9% of the total bacterial population, except in the microbiota of one C-type subject. However, the axillary bacteria in C-type subjects were more abundant than that in M-type subjects. These results suggest that the level of colonization by axillary bacteria is important for the production of malodorants.

Nitrate-nitrogen (NO3-N) and nitrite-nitrogen (NO2-N) are constituents of the nitrogen cycle. NO3-N is toxic to humans, primarily due to its reduction to NO2-N. In Japan, NO3-N and NO2-N levels in tap water must not exceed 10 mg/L and only NO2-N alone not 0.04 mg/L, respectively. In this study, we verified the effect of microorganisms and ultraviolet (UV) to increase of NO2-N in water. First, all tested drinking-waters including tap water and commercial mineral water in PET bottles had < 2 mg/L NO3-N and undetectable levels (< 0.01 mg/L) of NO2-N. However, we found that NO2-N was generated in tap water left to stand at room temperature for several days, leading to increases in CF and TC counts and reduction of NO3-N. We also demonstrated that direct UV and sunlight irradiation of NO3-N-containing drinking water generated NO2-N in 1-2 h, with NO2-N reaching > 0.04 mg/mL by 4-6 h. On the other hand, NO3-N and NO2-N were undetectable in commercially purified water.