Isolation and identification of the antimicrobial substance included in tempeh using Rhizopus stolonifer NBRC 30816 for fermentation

In this study, we focus on the antimicrobial properties of tempeh, a soybean fermented food, against oral bacteria. Tempeh showed antimicrobial activity against dental caries pathogenic bacterium Streptococcus mutans at a final concentration of 1 mg/mL. An antimicrobial substance contained in tempeh was present in the 100 kDa or greater fraction generated by ultrafiltration, but it was found not to be proteinaceous by native-PAGE, SDS-PAGE and protein degradation tests. Next, when the fraction was purified with an ODS column, the 80% and 100% methanol eluates showed antimicrobial activity against S. mutans. The 100% methanol eluate was further subjected to a 2nd column purification, and isolation of the target was confirmed by HPLC. When the isolated material was analyzed by ESI-MS, the m/z was 279.234. Further analysis by Raman spectroscopy revealed a peak similar to linoleic acid. This substance also possessed antimicrobial properties equivalent to linoleic acid

Sites of blood collection and topical disinfectants associated with contaminated cultures: An ambidirectional cohort study

Abstract Background We aimed to determine whether puncture sites for blood sampling and topical disinfectants are associated with rates of contaminated blood cultures in the emergency department (ED) of a single institution. Methods This single‐center, ambidirectional cohort study of 548 consecutive patients ≥20 years of age was performed in the ED of a university hospital in Japan over a 13‐month period. Pairs of blood samples were collected for aerobic and anaerobic cultures from patients in the ED. Physicians selected puncture sites and topical disinfectants according to their personal preference. Results Potential contamination was identified in 110 of the 548 patients (20.1%). One hundred fourteen (20.8%) patients showed true‐positive results for bacteremia, and 324 (59.1%) patients showed true‐negative results. Multivariate analysis revealed more frequent contamination when puncture sites were disinfected with povidone‐iodine (PVI) than with alcohol/chlorhexidine (ACHX) (adjusted risk difference, 19.1%; 95% confidence interval [CI]), 15.7–22.6; p < 0.001). In terms of blood collection sites, femoral and central venous (CV) catheter with PVI disinfection showed more frequent contamination than venous sites with ACHX (adjusted risk differences: 26.6%, 95% CI 21.3–31.9, p < 0.001 and 41.1%, 95% CI 22.2–59.9, p < 0.001, respectively). Conclusion Rates of contaminated blood cultures were significantly higher when blood was collected from the CV catheter or femoral sites with PVI as the topical disinfectant