Quorum quenching (QQ) has recently been acknowledged to be a sustainable antifouling strategy and has been investigated widely using lab-scale membrane bioreactor (MBR) systems. This study attempted to bring this QQ-MBR closer to potential practical application. Two types of pilot-scale QQ-MBRs with QQ bacteria entrapping beads (QQ-beads) were installed and run at a wastewater treatment plant, feeding real municipal wastewater to test the systems' effectiveness for membrane fouling control and thus the amount of energy savings, even under harsh environmental conditions. The rate of transmembrane pressure (TMP) build-up was significantly mitigated in QQ-MBR compared to that in a conventional-MBR. Consequently, QQ-MBR can substantially reduce energy consumption by reducing coarse bubble aeration without compromising the effluent water quality. The addition of QQ-beads to a conventional MBR substantially affected the EPS concentrations, as well as microbial floc size in the mixed liquor. Furthermore, the QQ activity and mechanical stability of QQ-beads were well maintained for at least four months, indicating QQ-MBR has good potential for practical applications.

Background : The in vivo skin prick test (SPT) or in vitro detection of allergen specific IgE in serum is commonly used for the diagnosis of allergic disease. In this study, we evaluated the usefulness of a new multiple allergen simultaneous test (MAST) immunoblot assay, Polycheck Allergy (Biocheck GmbH, Germany).Methods : A total of 100 patients with clinical findings of allergic diseases were tested by SPT and three different MAST assays: Polycheck Allergy (Biocheck GmbH, Germany), MAST CLA allergy system (Hitachi Chemical Diagnostics, USA) and Allergy Screen (R-biopharm, Germany). The results of MAST assays were compared with those of SPT.Results : Concordance rates of MAST assays with SPT were 79-100% for Polycheck Allergy, 88.9-100% for MAST CLA and 72.7-98.3% for Allergy Screen. In ROC curve analysis, significant differences were observed in four of 25 allergens analysed: Alternaria, Birch, Hazelnut and D. farinae. For Alternaria and Birch, Polycheck Allergy (P<0.001) and Allergy Screen (P=0.0075) showed significantly larger AUC (area under the curve) than MAST CLA. For Hazelnut, Polycheck Allergy (P=0.0021), and for D. farinae, MAST CLA (P=0.015) showed significantly larger AUCs than the other two tests. The ROC analysis for overall 16 food allergens showed better results in Polycheck Allergy (P<0.001), and that for overall 21 inhalants did not show significant differences among three MAST assays (P>0.05).Conclusions : Since Polycheck Allergy showed similar or superior result to the others, it can be used for the detection of allergen specific IgE antibodies. (Korean J Lab Med 2009;29:465-72)

Coronavirus disease 2019 (COVID-19) is rapidly spreading around the world, causing much morbidity and mortality everywhere. However, effective treatments or vaccines are still not available. Although convalescent plasma (CP) therapy can be useful in the treatment of COVID-19, it has not been widely used in Korea because of the concerns about adverse effects and the difficulty in matching patients to donors. The use of ABO-incompatible plasma is not contraindicated in treatment, but can be hesitated due to the lack of experience of physicians. Here, we describe a 68-year old man with COVID-19 who was treated ABO-incompatible plasma therapy; additionally, we comment on the acute side effects associated with ABO mismatch transfusion. To overcome the obstacles of donor-recipient connections (schedule and distance), we propose the storage of frozen plasma, modification of the current Blood Management Law, and the establishment of a CP bank. We suggest that experience gained in CP therapy will be useful for not only the treatment of COVID-19, but also for coping with new emerging infectious diseases.

Recently, membrane bioreactors (MBRs) with quorum quenching (QQ) bacteria entrapping beads have been reported as a new paradigm in biofouling control because, unlike conventional post-biofilm control methods, bacterial QQ can inhibit biofilm formation through its combined effects of physical scouring of the membrane and inhibition of quorum sensing (QS). In this study, using a special reporter strain (Escherichia coli JB525), the interaction between QS signal molecules and quorum quenching bacteria entrapping beads (QQ-beads) was elucidated through visualization of the QS signal molecules within a QQ-bead using a fluorescence microscope. As a result, under the conditions considered in this study, the surface area of QQ-media was likely to be a dominant parameter in enhancing QQ activity over total mass of entrapped QQ bacteria because QQ bacteria located near the core of a QQ-bead were unable to display their QQ activities. On the basis of this information, a more efficient QQ-medium, a QQ hollow cylinder (QQ-HC), was designed and prepared. In batch experiments, QQ-HCs showed greater QQ activity than QQ-beads as a result of their higher surface area and enhanced physical washing effect because of their larger impact area against the membrane surface. Furthermore, it was shown that such advantages of QQ-HCs resulted in more effective mitigation of membrane fouling than from QQ-beads in lab-scale continuous MBRs.

Chromobacterium violaceum is a gram-negative rod and is isolated from soil and water in tropical and subtropical regions. The species have pigmented and nonpigmented colony types. Infections caused by nonpigmented strains are rare. We report on two cases of infection caused by both pigmented and nonpigmented strains of C. violaceum. Two 24-year-old Korea Airline stewardesses were admitted to Inha University Hospital, Inchon, South Korea, on 9 August 1997, 3 days after an airplane accident in Guam. Both had multiple lacerations on exposed parts of their bodies. There was swelling, tenderness, and pus discharge. The wounds contained many small fragments of stones and weeds. A pigmented strain was isolated from the left hand and a nonpigmented strain was isolated from the left knee of one patient. For the other patient only a nonpigmented strain was isolated from a foot wound. The nonpigmented colonies from the left-knee and the left-foot wounds did not produce any pigment even after an extended period of incubation. The biochemical characteristics were the same for each strain except for oxidase and indole reactions. The pigmented strain was oxidase negative and indole positive, whereas the nonpigmented strains were oxidase positive and indole negative. The patients were successfully treated by debridement and with appropriate antibiotics.