BACKGROUND & AIMS: :The nature of the temporal relationship between antibacterial consumption and Streptococcus pneumoniae penicillin resistance is investigated using population level data across time. IMS Health Global Services provided national outpatient antibiotic prescription data for the years 1996-2003 from France, Spain, Italy, Germany, the United Kingdom, and the United States. Surveillance data consist of S. pneumoniae isolates obtained from a surveillance database in the same geographic regions from 1996 to 2003. A linear mixed model for repeated measures was used to analyze the association between resistance and several antibacterial classes through time. Changes in penicillin resistance through time in any country are better explained by the weighted cumulative antibacterial consumption with a 2-year lag. Narrow-spectrum penicillins are associated with lower resistance rates. Large reductions in consumption at the population level are needed to affect resistance. There is a peak level of penicillin resistance associated with cumulative exposure to a combination of antibiotic classes that is unique for every country.

背景与目标： : 使用跨时间的人群水平数据研究了抗菌药物消耗与肺炎链球菌青霉素耐药性之间的时间关系的性质。IMS Health Global Services提供了来自法国，西班牙，意大利，德国，英国和美国的1996-2003年全国门诊抗生素处方数据。监视数据由从2003年1996年相同地理区域的监视数据库中获得的肺炎链球菌分离株组成。使用用于重复测量的线性混合模型来分析耐药性与几种抗菌剂之间的关系。在任何国家，青霉素耐药性随时间的变化都可以通过滞后2年的加权累积抗菌药物消耗量来更好地解释。窄谱青霉素与较低的耐药率相关。为了影响抵抗力，需要大量减少人口消费。青霉素耐药性的峰值水平与累积暴露于抗生素类别的组合有关，这在每个国家都是独一无二的。

BACKGROUND & AIMS: :Phytochemical study on the leaves of Melaleuca bracteata resulted in the isolation of ten compounds including three new neolignans, named melaleucins A-C (1-3). Among them, melaleucin B shares a rarely occurring nor-neolignan skeleton, and both melaleucins B and C bear a novel aldehyde moiety, which might also be response for the delicate fragrance of M. bracteata. Their structures were extensively assigned by spectral data interpretation and biomimetic total synthesis. Moreover, their biosynthetic pathway with oxidative radical coupling and Michael addition as critical reactions was also confirmed. The antimicrobial activity evaluation revealed that melaleucin A exhibited considerable antimicrobial activity towards methicillin-resistant Staphylococcus aureus.

背景与目标： : 对白千层叶片的植物化学研究导致隔离出十种化合物，包括三种新的新木脂素，称为白千层蛋白A-C (1-3)。其中，白千层蛋白B具有很少出现的nor-neolignan骨架，并且白千层蛋白B和C都具有新的醛部分，这也可能是对M. bracteata的细腻香气的响应。通过光谱数据解释和仿生全合成广泛分配了它们的结构。此外，还证实了它们以氧化自由基偶联和迈克尔加成为关键反应的生物合成途径。抗菌活性评估表明，白千层素A对耐甲氧西林的金黄色葡萄球菌具有相当大的抗菌活性。

BACKGROUND & AIMS: :A series of 9-O-(3-aryl-2-propargyl)oxime ketolides 8 was synthesized and evaluated for in vitro antibacterial activity. Among 8, 8b-8d, and 8h-8l displayed dramatically improved potency against inducibly MLS(B)-resistant and efflux-resistant pathogens as compared to clarithromycin and azithromycin. Especially, 8i (Ar=4-isoquinolyl) possessed an MIC of 0.064 μg/mL against constitutively MLS(B)-resistant Streptococcus pneumoniae, and MICs of 0.032-0.064 μg/mL against methicillin-resistant Staphylococcus aureus and methicillin-resistant Staphylococcus hominis. The analog 10 with a propyl linker was less effective than both the corresponding 8 and 9 containing propynyl and propenyl linkers. A docking study was performed to gain insight into the binding mode of series 8 and 9 and to rationalize the disparity found in the SAR of 8 and 9.

背景与目标： : 合成了一系列9-O-(3-芳基-2-炔丙基) 肟酮内酯8，并评估了其体外抗菌活性。与克拉霉素和阿奇霉素相比，在8、8b-8d和8h-8l中，对诱导性MLS(B) 抗性和耐外排病原体的效力显着提高。尤其是，8i (Ar = 4-异喹啉基) 对组成型MLS(B) 耐药的肺炎链球菌的MIC为0.064 μ g/mL，对耐甲氧西林的金黄色葡萄球菌和耐甲氧西林的人型葡萄球菌的MIC为0.032-0.064 μ g/mL。具有丙基接头的类似物10的效力低于包含丙基和丙烯基接头的相应8和9的效力。进行了对接研究，以深入了解系列8和9的结合模式，并合理化在SAR 8和9中发现的差异。

BACKGROUND & AIMS: :Selected plants documented as medicinal in an ethnobotanical study with the Nahua of the Sierra de Zongolica (Veracruz, Mexico) were evaluated for anti-inflammatory and antibacterial activity. One of the potential sides of action of anti-inflammatory drugs is the transcription factor NF-κB. This factor is essential for the immune, inflammatory, and acute phase responses. We therefore tested extracts from a total of 28 plants used by the Nahua Indians for their potential effect on the activation of the transcription factor NF-κB. The leaves of Tithonia diversifolia (Hemsl.) A. Gray (Asteraceae) was the only extract which showed inhibitory activity. Nonspecific DNA binding activities were not noticably influenced. Phytochemical studies to isolate the active principle and further biochemical studies in order to better understand the mode of action of this NF-κB inhibitor have been initiated. Five plants showed noteworthy antibacterial activity against some pathogenic (Staphylococcus aureus ATCC 25933 and Yersinia enterocolitica 03) and nonpathogenic (E. coli DSM 1077, Micrococcus luteus DSM 348) microorganism: Acacia cornigera, Cuscuta tinctoria, Ludwigia octovalvis, Lysiloma divaricata, and Tithonia diversifolia.

背景与目标： : 在一项民族植物学研究中与Sierra de Zongolica (墨西哥韦拉克鲁斯) 的Nahua进行了记录为药用植物的抗炎和抗菌活性评估。抗炎药物的潜在作用方面之一是转录因子NF-κ b。该因素对于免疫，炎症和急性期反应至关重要。因此，我们测试了纳华印第安人使用的总共28种植物的提取物对转录因子NF-κ b激活的潜在影响。Tithonia diversifolia (Hemsl.) A.Gray (菊科) 是唯一具有抑制活性的提取物。非特异性DNA结合活性没有受到明显影响。分离活性原理的植物化学研究和进一步的生化研究已经开始，以便更好地了解这种NF-κ b抑制剂的作用方式。五种植物对某些致病性 (金黄色葡萄球菌ATCC 25933和小肠结肠炎耶尔森氏菌03) 和非致病性 (大肠杆菌DSM 1077，微球菌DSM 348) 微生物具有显着的抗菌活性: 金相相思，刺槐，octovalvis，Lysiloma divaricata和Tithonia diversifolia。

BACKGROUND & AIMS: :Crude methanol and water extracts of 36 plants, employed in the treatment of diseases of probable bacterial etiology by the Venda people, were screened for antibacterial activity. Combretum molle, Peltophorum africanum, Piper capense, Terminalia sericea and Zanthoxylum davyi were the most active and presented MIC values < or =1.00 mg/ml.

背景与目标： : 筛选了36种植物的粗甲醇和水提取物，用于治疗Venda人可能的细菌病因疾病，以进行抗菌活性筛选。康柏、非洲天竺葵、风笛、丝虫和花椒是最活跃的，MIC值 <或 = 1.00毫克/毫升。

BACKGROUND & AIMS: :As part of our ongoing research on the antibacterial activity of Achyrocline satureioides, this study seeks to better understand the interactions between the metabolites isolated from this plant. For this purpose, the combined effect of 23-methyl-6-O-desmethylauricepyrone (1), quercetin (2) and 3-O-methylquercetin (3), obtained through bioguided fractionation from A. satureioides ethanol extract, was evaluated against Staphylococcus aureus and Escherichia coli. In first place, the antibacterial effect of the combination of flavonols 2 and 3 was assessed, as these showed individual effectiveness lower than or equal to that of the fraction from which they were obtained. When the flavonols were applied together at concentrations below their minimum inhibitory concentration (MIC) values, a synergistic effect (FICI<0.30) against S. aureus was observed. In addition, compounds 2 and 3 in combination reduced 1000 times the MIC of compound 1, showing a clear synergistic interaction (FICI<0.15) in treatments against the Gram (+) bacterium. The most active combination against E. coli showed an additive interaction (FICI<0.62) between the three assayed compounds 1-3. These results indicated the existence of concerted action between these metabolites, evidence of the importance of the synergistic interactions between the components of plant-derived extracts for the control of pathogenic bacteria.

背景与目标： : 作为我们正在进行的有关阿奇霉素satureioides抗菌活性研究的一部分，本研究旨在更好地了解从该植物中分离出的代谢物之间的相互作用。为此，对金黄色葡萄球菌和大肠杆菌进行了评价，评价了通过生物导向分馏从金黄色葡萄球菌乙醇提取物中获得的23-methyl-6-O-desmethylauricepyrone (1) 、槲皮素 (2) 和3-o-甲基槲皮素 (3) 的联合作用。首先，评估了黄酮醇2和3的组合的抗菌效果，因为它们显示出低于或等于获得它们的级分的个体有效性。当黄酮醇以低于其最小抑制浓度 (MIC) 值的浓度一起施用时，观察到针对金黄色葡萄球菌的协同效应 (FICI<0.30)。此外，组合的化合物2和3降低了化合物1的1000倍MIC，在针对革兰氏 (+) 细菌的处理中显示出明显的协同相互作用 (FICI<0.15)。对大肠杆菌最有效的组合显示了三种测定的化合物1-3之间的加性相互作用 (FICI<0.62)。这些结果表明这些代谢物之间存在协同作用，这证明了植物提取物成分之间的协同相互作用对于控制致病菌的重要性。

BACKGROUND & AIMS: :Two abietane diterpenes were isolated from cyanobacteria Microcoleous lacustris, 20-nor-3alpha-acetoxyabieta-5,7,9,11,13-pentaene and 20-nor-3alpha-acetoxy-12-hydroxy-abieta-5,7,9,11,13-pentaene. These compounds were assayed against Staphylococcus aureus, Staphylococcus epidermidis, Salmonella typhi, Vibrio cholerae, Bacillus subtilis, Bacillus cereus, Escherichia coli, and Klebsiella pneumoniae. Both compounds showed activity against S. aureus, S. epidermidis, S. typhi, and V. cholerae, but not against the other bacteria.

背景与目标： : 从蓝藻微囊藻，20-nor-3alpha-acetoxyabieta-5，7,9、11、13-戊烯和20-nor-3alpha-acetoxy-12-hydroxy-abieta-5，7,9、11、13-戊烯中分离出两种阿比烷二萜。对这些化合物进行了金黄色葡萄球菌，表皮葡萄球菌，伤寒沙门氏菌，霍乱弧菌，枯草芽孢杆菌，蜡样芽孢杆菌，大肠杆菌和肺炎克雷伯菌的检测。两种化合物均显示出对金黄色葡萄球菌，表皮葡萄球菌，伤寒链球菌和霍乱弧菌的活性，但对其他细菌却没有。

BACKGROUND & AIMS: :An antibacterial metabolite was isolated from Paenibacillus polymyxa HKA-15, a soybean bacterial endophyte. The purification of the crude metabolite from Paenibacillus polymyxa HKA-15 was done by column chromatography. In TLC, a spot with an R ( f ) value of 0.86 (±0.02) from the purified fraction showed bioactivity against Xanthomonas campestris pv. phaseoli M-5. In SDS-PAGE, the purified antibiotic was separated in the molecular weight range of 3.5 kDa. The exact molecular weight of the active compound was identified as 1,347.7 Da using MS-MS analysis. Infra red spectrum and (1)H NMR analysis showed the presence of amino acids and fatty acids in the active compound. The characterization of the antibacterial compound revealed its lipopeptide nature. In an agar diffusion assay, the crude metabolite showed a broad spectrum of activity, being able to inhibit the growth of the fungal pathogen, Rhizoctonia bataticola, Macrophomina phaseolina and Fusarium udum. A stronger inhibition was observed against bacterial pathogens viz., X. campestris pv.phaseoli M-5, X. campestris pv. phaseoli CP-1-1, Xanthomonas oryzae, Ralstonia solanacearum and Micrococcus luteus.

背景与目标： : 从大豆细菌内生菌多粘芽孢杆菌HKA-15中分离出一种抗菌代谢物。通过柱色谱法纯化多粘芽孢杆菌HKA-15的粗代谢物。在TLC中，来自纯化级分的R (f) 值为0.86 (± 0.02) 的斑点显示出对黄单胞菌pv的生物活性。M-5。在sdds-PAGE中，纯化的抗生素在3.5 kDa的分子量范围内分离。使用ms-ms分析将活性化合物的确切分子量鉴定为1,347.7 Da。红外光谱和 (1)H NMR分析显示活性化合物中存在氨基酸和脂肪酸。抗菌化合物的表征揭示了其脂肽的性质。在琼脂扩散测定中，粗代谢物显示出广谱的活性，能够抑制真菌病原体，batataticola根瘤菌，菜豆和镰刀菌的生长。观察到对细菌病原体的更强抑制作用，即X. campestris pv.phaseoli M-5，X. campestris pv。菜豆CP-1-1、米黄单胞菌、青枯菌和黄小球菌。

BACKGROUND & AIMS: :The present study describes synthesis, characterization and antibacterial application of oxidized sodium alginate (OSA)-zinc oxide (ZnO) hybrid nanostructures (OSA-ZnO). In continuation to our previous study on oxidized guar gum (OGG)-ZnO (OGG-ZnO) nanocomposite, in the present study we have chosen OSA to understand the role of polysaccharide charge type in designing the antibacterial material. The nanomaterial has been characterized using UV-visible, FTIR, XRD, SEM and TEM analyses. The nanostructure has shown crystalline nature having hexagonal phase with preferred (101) orientation, while TEM image indicated that the material has ~6 nm particle size. It exhibited very good antibacterial performance against Bacillus subtilis (B. subtilis), Cellulomonas cellulans (C. cellulans), Staphylococcus typhi (S. typhi), and Escherichia coli (E. coli) bacterial strains, ZOI for B. subtilis, C. cellulans, S. typhi, and E. coli being 22, 18, 19.5 and 18.5 mm respectively. Under identical conditions, pure ZnO showed significantly lower ZOI for the corresponding bacterial strains (14, 12.5, 12 and 13.5 mm respectively), while native SA and OSA did not exhibit any biological activity.

背景与目标： : 本研究描述了氧化海藻酸钠 (OSA)-氧化锌 (ZnO) 杂化纳米结构 (OSA-ZnO) 的合成，表征和抗菌应用。为了继续我们先前对氧化瓜尔胶 (OGG)-ZnO (OGG-ZnO) 纳米复合材料的研究，在本研究中，我们选择了OSA来了解多糖电荷类型在设计抗菌材料中的作用。已使用UV-可见光，FTIR，XRD，SEM和TEM分析对纳米材料进行了表征。纳米结构显示了具有优选 (101) 取向的六方相的结晶性质，而TEM图像表明该材料具有约6 nm的粒度。对枯草芽孢杆菌 (B. subtilis)，纤维素单胞菌 (C.Celluloans)，伤寒葡萄球菌 (S. typhi) 和大肠杆菌 (E. coli) 细菌菌株，ZOI对枯草芽孢杆菌，C.Celluloans，S. typhi，大肠杆菌分别为22、18、19.5和18.5毫米。在相同条件下，纯ZnO对于相应的细菌菌株 (分别为14、12.5、12和13.5毫米) 显示出显著较低的ZOI，而天然SA和OSA不显示任何生物活性。

BACKGROUND & AIMS: AIMS:To evaluate the antibacterial activity of Artocarpus hirsutus mediated seed extract for nanoparticle synthesis. BACKGROUND:Gastrointestinal bacteria are known for causing deadly infections in humans. They also possess multi-drug resistance and interfere with clinical treatments. Applied nanotechnology has been known to combat such infectious agents with little interference from their special attributes. Here we synthesize silver nanoparticles from Artocarpus hirsutus seed extract against two gastro-intestinal bacterial species: Enterobacter aerogenes and Listeria monocytogenes. OBJECTIVE:To collect, dry, and process seeds of Artocarpus hirsutus for nanoparticle synthesis. To evaluate the morphological interaction of silver nanoparticles with bacteria. METHODS:Artocarpus hirsutus seeds were collected and processed and further silver nanoparticles were synthesized by the co-precipitation method. The synthesized nanoparticles were characterized using XRD, UV, FTIR, and SEM. These nanoparticles were employed to study the antibacterial activity of nanoparticles against Enterobacter aerogenes and Listeria monocytogenes using well diffusion method. Further, morphological interaction of silver nanoparticles on bacteria was studied using SEM. RESULTS:Silver nanoparticles were synthesized using Artocarpus hirsutus seed extract and characterization studies confirmed that silver nanoparticles were spherical in shape with 25-40 nm size. Antibacterial study exhibited better activity against Enterobacter aerogenes with a maximum zone of inhibition than on Listeria monocytogenes. SEM micrographs indicated that Enterobacter aerogenes bacteria were more susceptible to silver nanoparticles due to the absence of cell wall. Also, the size and charge of silver nanoparticles enable easy penetration of the bacterial cell wall. CONCLUSION:In this study, silver nanoparticles were synthesized using the seed extract of Artocarpus hirsutus for the first time exploiting the fact that Moraceae species have high phytonutrient content which aided in nanoparticle synthesis. This nanoparticle can be employed for large scale synthesis which when coupled with the pharmaceutical industry can be used to overcome the problems associated with conventional antibiotics to treat gastrointestinal bacteria.

背景与目标：

BACKGROUND & AIMS: :Common materials used in tissue engineering are not cost-effective and natural origin. Hence, we designed green, safe, and antibacterial bionanocomposite (bio-NC) films based on polysaccharides, chitosan (CS) and gum tragacanth (GT) for the bone tissue engineering. For this aim, different percentages of titanium dioxide nanoparticles (TiO2 NPs) and green silver (Ag)-doped TiO2 NPs (TiO2@Ag hybrid) were employed as nanofiller to improve the properties of the CS-GT film. Moreover, the physicochemical characteristics of the bio-NC films were examined with a field-emission scanning electron microscope (FE-SEM), Fourier transform infrared, X-ray diffraction, and transmission electron microscopy (TEM). The FE-SEM images showed a rough surface for the CS-GT/TiO2@Ag bio-NC films, and TEM images showed better dispersion of TiO2@Ag hybrid than TiO2 NPs into the CS-GT matrix. Also, these bio-NC films were considered for the bioactivity test and the results showed formation of hydroxyapatite on the surface of the prepared bio-NC films. Furthermore, addition of GT led to an increase in the bioactivity of the CS-GT blend. Finally, antibacterial behavior of the prepared bio-NC films was investigated against Escherichia coli and Staphylococcus aureus bacteria with/without ultraviolet irradiation and the results indicated better antibacterial performance for the CS-GT/TiO2@Ag bio-NC film (TiO2:Ag = 1:1) under both conditions.

背景与目标： : 组织工程中使用的常见材料不具有成本效益和天然来源。因此，我们为骨组织工程设计了基于多糖，壳聚糖 (CS) 和黄芪胶 (GT) 的绿色，安全和抗菌的生物纳米复合材料 (bio-NC) 膜。为此，采用不同百分比的二氧化钛纳米颗粒 (TiO2 NPs) 和绿银 (Ag) 掺杂的TiO2 NPs (TiO2 @ Ag杂化) 作为纳米填料，以改善CS-GT膜的性能。此外，还使用场发射扫描电子显微镜 (fe-sem)，傅立叶变换红外，x射线衍射和透射电子显微镜 (TEM) 检查了bio-NC薄膜的理化特性。Fe-sem图像显示CS-GT/TiO2 @ Ag bio-NC膜的表面粗糙，TEM图像显示TiO2 @ Ag杂化物比TiO2 np更好地分散到CS-GT基体中。此外，这些bio-NC膜被考虑用于生物活性测试，结果表明在所制备的bio-NC膜的表面上形成了羟基磷灰石。此外，GT的添加导致CS-GT共混物的生物活性增加。最后，研究了制备的bio-NC膜在紫外线照射下对大肠杆菌和金黄色葡萄球菌的抗菌性能，结果表明CS-GT/TiO2 @ Ag bio-NC膜 (TiO2:Ag = 1:1) 在两种条件下均具有更好的抗菌性能。

BACKGROUND & AIMS: -2

背景与目标： -2

BACKGROUND & AIMS: OBJECTIVE:The study investigated the effect of incorporating l-arginine (Arg) in a glass ionomer cement (GIC) on its mechanical properties and antibacterial potential. METHODS:Pre-determined proportions (1%, 2%, and 4% by wt.) of Arg were incorporated in GIC powder; while GIC without Arg served as control. The flexural strength, nanohardness, surface roughness, elemental analysis using SEM-EDX (n = 6) and F/Arg/Ca/Al/Si release in deionized water for 21 days were assessed. The antibacterial potential was evaluated in a multi-species biofilm model with Streptococcus mutans, Streptococcus sanguinis, Streptococcus gordonii, and Lactobacillus acidophilus for 72 h. Real-time qPCR was used to analyse biofilm bacterial concentrations. Propidium monoazide modification of real-time qPCR was performed to quantify viable/dead bacteria. The pH, lactic acid, ADS activity, and H2O2 metabolism were measured. Confocal microscopy was used to investigate the biofilm bacterial live/dead cells, density, and thickness. RESULTS:There was no difference in flexural strength among the different groups (p > 0.05). No significant difference in nanohardness and surface roughness was observed between 4% Arg + GIC and control (p > 0.05). The 4% Arg + GIC showed significantly higher F/Arg/Al/Si release than the other groups (p < 0.05), reduced total bacterial concentration and growth inhibition of viable S. mutans and S. sanguinis (p < 0.05). Lactic acid formation for 4% Arg + GIC was significantly higher than 1% Arg + GIC (p < 0.05). The spent media pH of 4% Arg + GIC was higher than the other groups (p < 0.05), with proportionately lower ammonia and higher H2O2 released (p < 0.05). SIGNIFICANCE:Addition of 4% l-arginine in GIC enhanced its antibacterial activity via a biofilm modulatory effect for microbial homeostasis, with no detrimental effect on its mechanical properties.

背景与目标：

BACKGROUND & AIMS: :Previously, we purified a serine protease with a molecular mass of 26 kDa that exhibits potent antibacterial activity from a pupal extract of Sarcophaga peregrina (flesh fly). We divided this protease into 12 peptides and examined their antibacterial activity. A peptide corresponding to residues 155 to 174 (peptide 9) was found to exhibit antibacterial activity comparable to that of the 26-kDa protease. When Escherichia coli was treated with peptide 9, the permeability of both the outer and inner membranes increased, and substrates for beta-lactamase and beta-galactosidase entered the cells, but beta-galactosidase did not leak out of the cells under these conditions. It was suggested that residues 6 to 18 of peptide 9 form an amphiphilic alpha-helix under hydrophobic conditions with an N-terminal basic loop and then interact with acidic phospholipids in the bacterial membranes.

背景与目标： : 以前，我们从sarcopoga peregrina (肉蝇) 的p提取物中纯化了分子量为26 kDa的丝氨酸蛋白酶，该蛋白酶具有有效的抗菌活性。我们将这种蛋白酶分为12个肽，并检查了它们的抗菌活性。发现对应于残基155至174的肽 (肽9) 表现出与26-kda蛋白酶相当的抗菌活性。当用肽9处理大肠杆菌时，外膜和内膜的通透性均增加，β-内酰胺酶和 β-半乳糖苷酶的底物进入细胞，但在这些条件下 β-半乳糖苷酶不会泄漏出细胞。建议肽9的残基6至18在疏水条件下形成具有N末端碱性环的两亲性 α 螺旋，然后与细菌膜中的酸性磷脂相互作用。

BACKGROUND & AIMS: :The antibacterial effect of light emitting diodes (LEDs) in the visible region (461, 521 and 642 nm) of the electromagnetic spectrum was investigated on Escherichia coli O157:H7, Salmonella typhimurium, Listeria monocytogenes and Staphylococcus aureus. The irradiances of the 461, 521 and 642 nm LEDs were 22.1, 16 and 25.4 mW/cm², respectively. Bacterial cultures suspended in tryptic soy broth were illuminated by 10-watt LEDs at a distance of 4.5 cm for 7.5h at 20, 15 and 10 °C. Regardless of the bacterial strains, bacterial inactivation was observed with the range of 4.6-5.2 logCFU/ml at 10 and 15 °C after illumination with the 461 nm LED, while illumination with the 521 nm LED resulted in only 1.0-2.0 log reductions after 7.5h. On the other hand, no antibacterial effect was observed using the 642 nm LED treatment. The photodynamic inactivation by 461 and 521 nm LEDs was found to be greater at the set temperatures of 10 and 15 °C than at 20 °C. The D-values for the four bacterial strains at 10 and 15 °C after the illumination of 461 nm LED ranged from 1.29 to 1.74 h, indicating that there was no significant difference in the susceptibility of the bacterial strains to the LED illumination between 10 and 15 °C, except for L. monocytogenes. Regardless of the illumination temperature, sublethal injury was observed in all bacterial strains during illumination with the 461 and the 521 nm LED and the percentage of injured cells increased as the treatment time increased. Thus, the results show that the antibacterial effect of the LEDs was highly dependent on the wavelength and the illumination temperature. This study suggests the potential of 461 and 521 nm LEDs in combination with chilling to be used as a novel food preservation technology.

背景与目标： : 在大肠杆菌O157:H7，鼠伤寒沙门氏菌，单核细胞增生李斯特菌和金黄色葡萄球菌上研究了电磁光谱的可见区域 (461，521和642 nm) 中发光二极管 (led) 的抗菌作用。461、521和642 nm led的辐照度分别为22.1、16和25.4 mW/cm ²。悬浮在胰蛋白酶大豆肉汤中的细菌培养物在20、15和10 °C下以4.5厘米的距离用10瓦led照射7.5小时。无论细菌菌株如何，在用461 nm LED照明后，在10和15 °C下观察到4.6-5.2 logCFU/ml范围内的细菌失活，而用521 nm LED照明在7.5小时后仅导致1.0-2.0 log减少。另一方面，使用642 nm LED处理未观察到抗菌效果。发现461和521 nm led的光动力失活在10和15 °C的设定温度下比在20 °C下更大。在461 nm LED照射后，4个细菌菌株在10和15 °C的d值范围为1.29至1.74小时，表明除了单核细胞增生李氏菌以外，在10和15 °C之间细菌菌株对LED照射的敏感性没有显著差异。不管照射温度如何，在用461和521 nm LED照射期间，在所有细菌菌株中观察到亚致死损伤，并且损伤细胞的百分比随着处理时间的增加而增加。因此，结果表明，led的抗菌效果高度依赖于波长和照明温度。这项研究表明，461和521 nm led与冷却相结合的潜力可用作新型食品保存技术。