BACKGROUND & AIMS: :Pseudomonas aeruginosa PACL strain, isolated from oil-contaminated soil taken from a lagoon, was used to investigate the efficiency and magnitude of biosurfactant production, using different waste frying soybean oils, by submerged fermentation in stirred tank reactors of 6 and 10 l capacities. A complete factorial experimental design was used, with the goal of optimizing the aeration rate (0.5, 1.0, and 1.5 vvm) and agitation speed (300, 550, and 800 rpm). Aeration was identified as the primary variable affecting the process, with a maximum rhamnose concentration occurring at an aeration rate of 0.5 vvm. At optimum levels, a maximum rhamnose concentration of 3.3 g/l, an emulsification index of 100%, and a minimum surface tension of 26.0 dynes/cm were achieved. Under these conditions, the biosurfactant production derived from using a mixture of waste frying soybean oil (WFSO) as a carbon source was compared to production when non-used soybean oil (NUSO), or waste soybean oils used to fry specific foods, were used. NUSO produced the highest level of rhamnolipids, although the waste soybean oils also resulted in biosurfactant production of 75-90% of the maximum value. Under ideal conditions, the kinetic behavior and the modeling of the rhamnose production, nutrient consumption, and cellular growth were established. The resulting model predicted data points that corresponded well to the empirical information.

背景与目标： : 铜绿假单胞菌PACL菌株是从泻湖中提取的受油污染的土壤中分离出来的，用于研究使用不同的废油炸大豆油在6和10 l的搅拌釜反应器中进行深层发酵的生物表面活性剂生产的效率和规模容量。使用了完整的析因实验设计，目的是优化曝气速率 (0.5，1.0和1.5 vvm) 和搅拌速度 (300，550和800 rpm)。曝气被确定为影响该过程的主要变量，最大鼠李糖浓度发生在0.5 vvm的曝气速率下。在最佳水平下，最大鼠李糖浓度为3.3g/l，乳化指数为100%，最小表面张力为26.0 dynes/cm。在这些条件下，将使用废油炸大豆油 (WFSO) 混合物作为碳源的生物表面活性剂生产与使用非用大豆油 (NUSO) 或用于油炸特定食品的废大豆油的生产进行了比较。NUSO产生了最高水平的鼠李糖脂，尽管废大豆油也导致生物表面活性剂产生了最大值的75-90%。在理想条件下，建立了鼠李糖生产，养分消耗和细胞生长的动力学行为和模型。生成的模型预测了与经验信息非常对应的数据点。

BACKGROUND & AIMS: :Pseudomonas aeruginosa is a gram-negative opportunistic pathogen that is cytotoxic towards a variety of eukaryotic cells. To investigate the effect of this bacterium on monocyte, we infected human U937 cells with the P. aeruginosa strain in vitro. To explore the expression of Bcl-2 and Bax as well as caspase-3/9 activation in the apoptosis of human U937 cells induced by P. aeruginosa, Hoechst 33258 staining and Giemsa staining as well as Flow cytometry analysis were used to determine the rate of apoptosis, and the expressions of Bcl-2 and Bax were assayed by RT-PCR and Western blotting respectively. Bax protein conformation change was assayed by immunoprecipitation. Cytochrome c release was measured by Western blotting. Moreover, exposure of U937 cells to P. aeruginosa measured caspase-3/9 activity. It was found that the apoptosis of human U937 cells could be induced by Pseudomonas aeruginosa in a dose- and time-dependent manner. Also, there were a tendency of alterations with an increased expression level of Bax and a reduced expression level of Bcl-2, increased levels of cytochrome c release, and also with an increased activation of caspase-3/9 and Bax protein conformation change. For the evaluation of the role of caspases, caspase-3/9 inhibitors Z-DEVD-FMK and Z-LEHD-FMK respectively were used. The results were further confirmed by the observation that the caspase inhibitors Z-DEVD-FMK and Z-LEHD-FMK blocked P. aeruginosa-induced U937 apoptosis. It is concluded that P. aeruginosa can induce apoptosis with an up-regulated expression of Bax and a down-regulated expression of Bcl-2, which resulted in increased levels of cytochrome c release and increased caspase-3 and -9 in human U937 cells.

背景与目标： 铜绿假单胞菌是一种革兰氏阴性机会性病原体，对多种真核细胞具有细胞毒性。为了研究这种细菌对单核细胞的影响，我们在体外用铜绿假单胞菌菌株感染了人U937细胞。为探讨铜绿假单胞菌诱导人U937细胞凋亡中Bcl-2和Bax的表达以及caspase-3/9的激活，采用Hoechst 33258染色和Giemsa染色以及流式细胞仪分析测定凋亡率。用rt-pcr和Western blotting分别检测Bcl-2和Bax的表达。通过免疫沉淀测定Bax蛋白构象变化。通过蛋白质印迹法测量细胞色素c的释放。此外，暴露于铜绿假单胞菌的U937细胞可测量caspase-3/9活性。发现铜绿假单胞菌可以剂量和时间依赖性地诱导人U937细胞的凋亡。此外，随着Bax表达水平的增加和Bcl-2表达水平的降低，细胞色素c释放水平的增加以及caspase-3/9和Bax蛋白构象变化的增加，存在改变的趋势。为了评估半胱天冬酶的作用，分别使用caspase-3/9抑制剂Z-DEVD-FMK和Z-LEHD-FMK。观察结果进一步证实，caspase抑制剂Z-DEVD-FMK和Z-LEHD-FMK阻断了铜绿假单胞菌诱导的U937凋亡。结论铜绿假单胞菌可诱导凋亡，Bax表达上调，Bcl-2表达下调，导致人U937细胞细胞色素c释放水平升高，caspase-3和-9增加。

BACKGROUND & AIMS: :In this study, oxygen and nitrate regulation of transcription and subsequent protein expression of the unique narK1K2GHJI respiratory operon of Pseudomonas aeruginosa were investigated. Under the control of PLAC, P. aeruginosa was able to transcribe nar and subsequently express methyl viologen-linked nitrate reductase activity under aerobic conditions without nitrate. Modulation of PLAC through the LacI repressor enabled us to assess both transcriptional and posttranslational regulation by oxygen during physiological whole-cell nitrate reduction.

背景与目标： : 在这项研究中，研究了铜绿假单胞菌独特的narK1K2GHJI呼吸操纵子的氧和硝酸盐对转录的调节以及随后的蛋白表达。在PLAC的控制下，铜绿假单胞菌能够转录nar，随后在有氧条件下无硝酸盐的情况下表达甲基紫精连接的硝酸还原酶活性。通过LacI阻遏物对PLAC的调节使我们能够评估生理全细胞硝酸盐还原过程中氧气的转录和翻译后调节。

BACKGROUND & AIMS: :Basic Violet 3 and Acid Blue 93 are the most important group of synthetic colourants extensively used in textile industries for dyeing cotton, wool, silk and nylon. Release of these dye pollutants in to the environment adversely affects the human health and aquatic organisms. The present study we used Pseudomonas putida MTCC 4910 for the adsorptive removal of Basic Violet 3 and Acid Blue 93 from the aqueous solutions. The pH (4-9) and NaCl concentrations (1mM-1M) did not influence the adsorption process. The equilibrium adsorption process fitted well to Freundlich model than Langmuir model. The kinetics of adsorption fitted well by pseudo-second-order. Thus in the present study an attempt has been made to exploit the dye removal capability of P. putida MTCC 4910, and it was found to be an efficient microbe that could be used for bio removal of dyes from textile effluents.

背景与目标： : 碱性紫罗兰3和酸性蓝93是最重要的合成着色剂组，广泛用于纺织工业中，用于棉，羊毛，丝绸和尼龙的染色。将这些染料污染物释放到环境中会对人类健康和水生生物产生不利影响。本研究使用恶臭假单胞菌MTCC 4910从水溶液中吸附去除碱性紫3和酸性蓝93。pH (4-9) 和NaCl浓度 (1mm-1m) 不影响吸附过程。平衡吸附过程比Langmuir模型更适合Freundlich模型。伪二阶吸附动力学拟合良好。因此，在本研究中，已经尝试利用P. putida MTCC 4910的染料去除能力，并且发现它是一种有效的微生物，可用于从纺织品流出物中生物去除染料。

BACKGROUND & AIMS: :Pseudomonas aeruginosa is a highly resistant opportunistic pathogen and an important etiological agent of various types of infections. During the last decade, P. aeruginosa phages have been extensively examined as alternative antimicrobial agents. The aim of the study was to determine antimicrobial effectiveness of combining subinhibitory concentrations of gentamicin, ceftriaxone, ciprofloxacin or polymyxin B with P. aeruginosa-specific bacteriophages belonging to families Podoviridae and Siphoviridae. The time-kill curve method showed that a combination of bacteriophages and subinhibitory concentrations of ceftriaxone generally reduced bacterial growth, and synergism was proven for a Siphoviridae phage σ-1 after 300 min of incubation. The detected alteration in morphology after ceftriaxone application, resulting in cell elongation, along with its specific mode of action, seemed to be a necessary but was not a sufficient reason for phage-antibiotic synergism. The phenomenon offers an opportunity for future development of treatment strategies for potentially lethal infections caused by P. aeruginosa.

背景与目标： : 铜绿假单胞菌是一种高度耐药的机会致病菌，是各种类型感染的重要病原体。在过去的十年中，铜绿假单胞菌噬菌体已被广泛研究为替代抗菌剂。该研究的目的是确定将亚抑制浓度的庆大霉素，头孢曲松，环丙沙星或多粘菌素b与属于Podoviridae和Siphoviridae家族的铜绿假单胞菌特异性噬菌体相结合的抗菌效果。时间杀伤曲线方法表明，噬菌体和亚抑菌浓度的头孢曲松的组合通常会降低细菌的生长，并且在孵育300分钟后证明了Siphoviridae噬菌体 σ-1的协同作用。头孢曲松应用后检测到的形态变化，导致细胞伸长及其特定的作用方式，似乎是必要的，但不是噬菌体-抗生素协同作用的充分理由。该现象为未来发展由铜绿假单胞菌引起的潜在致命感染的治疗策略提供了机会。

BACKGROUND & AIMS: :Plant pathogenic Pseudomonas syringae produce the hydroxy-β-lactam antimetabolite tabtoxinine-β-lactam (TβL) as a time-dependent inactivating glutamine analogue of plant glutamine synthetases. The producing pseudomonads use multiple modes of self-protection, two of which are characterized in this study. The first is the dipeptide ligase TblF which converts tabtoxinine-β-lactam to the TβL-Thr dipeptide known as tabtoxin. The dipeptide is not recognized by glutamine synthetase. This represents a Trojan Horse strategy: the dipeptide is secreted, taken up by dipeptide permeases in neighboring cells, and TβL is released by peptidase action. The second self-protection mode is elaboration by the acetyltransferase Ttr, which acetylates the α-amino group of the proximal inactivator TβL, but not the tabtoxin dipeptide.

背景与目标： : 植物致病性丁香假单胞菌产生羟基-β-内酰胺抗代谢物tabtoxinine-β-内酰胺 (t β l)，作为植物谷氨酰胺合成酶的时间依赖性失活谷氨酰胺类似物。产生的假单胞菌使用多种自我保护模式，本研究对其中两种模式进行了表征。第一种是二肽连接酶TblF，它将tabtoxinine-β-内酰胺转化为称为tabtoxin的TβL-Thr二肽。二肽不能被谷氨酰胺合成酶识别。这代表了特洛伊木马策略: 二肽被分泌，被邻近细胞中的二肽permeases所占据，而t β l通过肽酶作用被释放。第二种自我保护模式是通过乙酰基转移酶Ttr进行细化，该乙酰基转移酶使近端灭活因子t β l的 α-氨基乙酰化，但不使毒素二肽乙酰化。

BACKGROUND & AIMS: Growth of Pseudomonas aeruginosa ATCC 15692 was promoted when the strain was cultured in an iron-depleted succinate medium, supplemented with transferrin at 30%, 60% and 100% and lactoferrin at 60% and 100% iron-saturation. No significant differences between cell growth and pyoverdin production were observed when transferrin iron saturation was increased from 30% to 100%; however, cell growth and pyoverdin production were strongly dependent on lactoferrin iron saturation. Lower lactoferrin iron saturation (< 30%) resulted in more pyoverdin production and reduced cell growth. Incubation of pyoverdin (1.0 microM) with 10.0 microM transferrin (30%, 60% and 100% iron-saturated) or lactoferrin (60% and 100% iron-saturated) led to quenching of pyoverdin fluorescence. Also, 24 h incubation of pyoverdin (20.0 microM) with these two proteins (20.0 microM, 30%, 60% and 100% iron-saturated transferrin and 60% and 100% iron-saturated lactoferrin) at 25 degrees C resulted in increased absorbance at 460 nm. Both the fluorescence quenching and absorbance increases were iron-saturation-dependent. Taken together, these results support the conclusion that at physiological pH, P. aeruginosa pyoverdin can acquire from partially iron-saturated transferrin or lactoferrin.

背景与目标： 当菌株在贫铁琥珀酸培养基中培养时，促进铜绿假单胞菌ATCC 15692的生长，该培养基补充有30%，60% 和100% 的转铁蛋白和60% 和100% 的铁饱和度的乳铁蛋白。当转铁蛋白铁饱和度从30% 增加到100% 时，未观察到细胞生长和pyoverdin产生之间的显着差异; 然而，细胞生长和pyoverdin产生强烈依赖于乳铁蛋白铁饱和度。较低的乳铁蛋白铁饱和度 (< 30%) 导致更多的pyoverdin产生和降低的细胞生长。pyoverdin (1.0微米) 与10.0微米转铁蛋白 (30% 、60% 和100% 铁饱和) 或乳铁蛋白 (60% 和100% 铁饱和) 的孵育导致pyoverdin荧光的猝灭。此外，pyoverdin (20.0 microM) 与这两种蛋白质 (20.0 microM、30% 、60% 和100% 铁饱和转铁蛋白以及60% 和100% 铁饱和乳铁蛋白) 在25 ℃ 下孵育24小时导致在460 nm处的吸光度增加。荧光猝灭和吸光度的增加都是铁饱和度依赖性的。综上所述，这些结果支持以下结论: 在生理pH下，铜绿假单胞菌pyoverdin可以从部分铁饱和的转铁蛋白或乳铁蛋白中获得。

BACKGROUND & AIMS: :Cyclic diguanylate (c-di-GMP) is a broadly conserved bacterial signalling molecule that modulates diverse cellular processes, such as biofilm formation, colony morphology and swimming motility. The intracellular level of c-di-GMP is controlled by diguanylate cyclases (DGCs) with GGDEF domain and phosphodiesterases (PDEs) with either EAL or HD-GYP domain. Pseudomonas putida KT2440 has a large group of genes on its genome encoding proteins with GGDEF/EAL/HD-GYP domains. However, phenotypic-genotypic correlation and c-di-GMP metabolism of these genes were largely unknown. Herein, by systematically constructing deletion mutants/overexpression strains of the 42 predicted c-di-GMP metabolism-related genes and analysing the phenotypes, we preliminarily revealed the role of each gene in biofilm formation, colony morphology and swimming motility. Subsequent results from protein sequence alignments and cellular c-di-GMP assessment indicated that 25 out of the 42 genes were likely to encode DGCs, nine genes were predicted to encode PDEs, four genes encoded bifunctional enzymes and the other four genes encoded enzymatically inactive proteins. This study offers a basic understanding of the roles of these 42 genes and can serve as a toolkit for investigators to further elucidate the functions of these GGDEF and EAL/HD-GYP domain-containing proteins.

背景与目标： : 环二鸟苷酸 (c-di-GMP) 是一种广泛保守的细菌信号分子，可调节多种细胞过程，例如生物膜形成，菌落形态和游泳运动。c-di-GMP的细胞内水平由具有GGDEF结构域的双鸟苷酸环化酶 (dgc) 和具有EAL或HD-GYP结构域的磷酸二酯酶 (pde) 控制。恶臭假单胞菌KT2440在其基因组上有大量基因，编码具有GGDEF/EAL/hd-gyp结构域的蛋白质。然而，这些基因的表型-基因型相关性和c-di-GMP代谢在很大程度上是未知的。在此，通过系统构建42个预测的c-di-GMP代谢相关基因的缺失突变体/过表达菌株并分析表型，我们初步揭示了每个基因在生物膜形成，菌落形态和游泳运动中的作用。蛋白质序列比对和细胞c-di-GMP评估的后续结果表明，42个基因中有25个可能编码DGCs，预计有9个基因编码pde，4个基因编码双功能酶，其他4个基因编码酶无活性蛋白。这项研究提供了对这42个基因作用的基本理解，并可以作为研究人员进一步阐明这些GGDEF和EAL/hd-gyp结构域蛋白功能的工具包。

BACKGROUND & AIMS: BACKGROUND:Up to 90% of children develop Pseudomonas aeruginosa (Pa)-positive respiratory cultures after tracheotomy. OBJECTIVE:To identify the factors associated with chronic Pa-positive respiratory cultures in the first 2 years after tracheotomy. METHODS:We conducted a retrospective cohort study of 210 children ≤ 18 years old who underwent tracheotomy at a single freestanding children's hospital that had two or more years of respiratory cultures post-tracheotomy available for analysis. We conducted multivariable logistic regression to test the association between demographic and clinical factors to our primary outcome of chronic Pa infection, defined as > 75% of respiratory cultures positive for Pa in the first 2 years after tracheotomy. RESULTS:Of the primarily male (61%), Hispanic (68%), and publicly insured (88%) cohort, 18% (n = 37) developed chronic Pa-positive respiratory cultures in the first 2 years. On multivariable logistic regression, pre-tracheotomy Pa-positive respiratory culture (aOR 11.3; 95% CI 4-1.5) and discharge on beta agonist (aOR 6.3; 95% CI 1.1-36.8) were independently associated with chronic Pa-positive respiratory cultures, while discharge on chronic mechanical ventilation was associated with decreased odds (aOR 0.3; 95% CI 0.1-0.7). On sensitivity analysis examining those without a pre-tracheotomy Pa-positive respiratory culture, discharge on MV continued to be associated with decreased odds of chronic Pa (aOR 0.1; 95% CI 0.02-0.4) and three other variables (male gender, chronic lung disease, and discharge on inhaled corticosteroids) were associated with increased odds of chronic Pa. CONCLUSION:Because pre-tracheotomy Pa growth on respiratory culture is associated with post-tracheotomy chronic Pa-positive respiratory cultures, future research should examine pre-tracheotomy Pa eradication or suppression protocols.

背景与目标：

BACKGROUND & AIMS: :Denitrification and arginine fermentation are major parts of the anaerobic metabolism of Pseudomonas aeruginosa, which is important for biofilm formation and infection. The two-component regulatory system NarX-NarL is part of the underlying network and is required for denitrifying growth. All target promoters identified so far are activated by NarL. In this study the effect of NarL on arginine fermentation was investigated using proteome, Northern blot and lacZ reporter gene analyses. NarL-dependent repression of the arcDABC operon was observed and the corresponding NarL-binding site in the arcD promoter region was functionally localized at -60 bp upstream of the transcriptional start site using site-directed promoter mutagenesis and reporter gene fusion experiments. The results clearly show that in the presence of nitrate NarL represses the arginine-dependent activation of the arcDABC operon mediated by ArgR. It does not influence the oxygen-tension-dependent activation via Anr. Thus, the anaerobic energy metabolism of P. aeruginosa is coordinated via NarX-NarL activity. In the presence of nitrate the highly efficient denitrification is preferred over the less attractive arginine fermentation.

背景与目标： : 反硝化和精氨酸发酵是铜绿假单胞菌厌氧代谢的主要组成部分，对生物膜的形成和感染具有重要意义。两部分监管系统narx-narl是基础网络的一部分，是反硝化增长所必需的。到目前为止，所有鉴定的靶启动子都被NarL激活。在这项研究中，使用蛋白质组，Northern印迹和lacZ报告基因分析研究了NarL对精氨酸发酵的影响。使用定点启动子诱变和报告基因融合实验，观察到arcDABC操纵子的NarL依赖性抑制，并且arcD启动子区域中相应的NarL结合位点功能定位在转录起始位点上游-60 bp。结果清楚地表明，在存在硝酸盐的情况下，NarL抑制arcDABC操纵子的精氨酸依赖性激活。它不会通过Anr影响氧张力依赖性激活。因此，铜绿假单胞菌的厌氧能量代谢是通过NarX-NarL活性协调的。在硝酸盐存在下，与吸引力较小的精氨酸发酵相比，高效的反硝化作用是优选的。

BACKGROUND & AIMS: :Metallo-β-lactamases (MBL) producing Pseudomonas aeruginosa isolates have been well characterized. Quinolones are commonly used in the treatment of carbapenem-resistant P. aeruginosa infections; however, data about PMQR in this species are scarce. The objective of this study was to report the simultaneous presence of qnrS and blaVIM-11 in P. aeruginosa, and to characterize the qnrS-harboring plasmid. Thirty-eight carbapenem-resistant P. aeruginosa isolates were recovered from a hospital in Buenos Aires during 2012. Screening for MBL was assessed by the double disk synergy test using EDTA and carbapenem discs. Plasmid DNA extraction was performed by a method using phenol-chloroform. PCR followed by sequencing was carried out to determine each MBL and PMQR allele. PCR-BseGI-RFLP was performed to detect aac-(6')-Ib-cr. The gyrA-QRDR was sequenced in those PMQR-harboring isolates. Plasmid incompatibility groups and addiction systems were characterized by PCR. The PMQR-carrying plasmid was sequenced using Illumina technology, annotated using RAST and manually curated. Eleven/38 isolates were VIM producers (blaVIM-2 and blaVIM-11) while 1/38 harbored blaIMP-13. One isolate harbored blaVIM-11 and the PMQR qnrS1; however, both markers were located in different plasmids. The qnrS1-harboring plasmid (pP6qnrS1) was 117945bp in size, presented 154 CDS and corresponded to the IncR group. In addition to qnrS1, it harbored several aminoglycoside resistance markers. Although pP6qnrS1 was non-conjugative, it presented an oriT which made it possible for this plasmid to be transferable. This is the first report on P. aeruginosa carrying both blaVIM-11 and qnrS1, plus the first detection of an IncR plasmid in Argentina.

背景与目标： : 产生铜绿假单胞菌的金属-β-内酰胺酶 (MBL) 已得到很好的表征。喹诺酮类药物通常用于治疗耐碳青霉烯类药物的铜绿假单胞菌感染; 但是，该物种中有关PMQR的数据很少。这项研究的目的是报告铜绿假单胞菌中qnrS和blaVIM-11的同时存在，并表征携带qnrS的质粒。2012年从布宜诺斯艾利斯的一家医院回收了38株耐碳青霉烯的铜绿假单胞菌。通过使用EDTA和碳青霉烯类圆盘的双圆盘协同试验评估MBL的筛选。通过使用苯酚-氯仿的方法进行质粒DNA提取。进行PCR，然后进行测序以确定每个MBL和PMQR等位基因。进行PCR-BseGI-RFLP检测aac-(6 ')-Ib-cr。gyrA-QRDR在那些携带PMQR的分离株中进行了测序。通过PCR表征质粒不相容组和成瘾系统。携带PMQR的质粒使用Illumina技术进行测序，使用RAST注释并手动整理。11/38个分离株是VIM生产者 (blaVIM-2和blaVIM-11)，而1/38个具有blaIMP-13。一个分离物携带blaVIM-11和PMQR qnrS1; 然而，两个标记都位于不同的质粒中。qnrS1-harboring质粒 (pP6qnrS1) 大小为117945bp，呈现154个CDS，对应于IncR组。除qnrS1外，它还具有几种氨基糖苷类抗性标记。尽管pP6qnrS1是非共轭的，但它呈现了oriT，使该质粒可以转移。这是关于同时携带blaVIM-11和qnrS1的铜绿假单胞菌的首次报道，以及在阿根廷首次检测到IncR质粒。

BACKGROUND & AIMS: :Resistant microorganisms such as Pseudomonas aeruginosa grow by developing biofilms in hospitals. We aimed to investigate the biofilm formation and the frequencies of biofilm-related genes and their associations with antibiotic resistance pattern in P. aeruginosa isolated from Iranians' clinical samples. This review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We conducted a systematic literature search in scientific databases using medical subject heading terms, including "Pseudomonas aeruginosa," "biofilm formation," "biofilm-related genes," "antibiotic resistance," and "prevalence," to obtain related articles published from 1st January, 2000, to 30th March, 2019. The studies reporting the prevalence of biofilm formation, the frequencies of biofilm-related genes, and the antibiotic resistance pattern in P. aeruginosa retrieved from Iranian patients were included. Meta-analysis was performed using the Comprehensive Meta-Analysis software. The pooled rate of biofilm formation was calculated as 86.5% (95% confidence interval [CI]: 79-91.6). The combined frequencies of strong, moderate, and weak biofilms were 51% (95% CI: 37.4-64.4), 29.2% (95% CI: 20.9-39.1), and 25.4% (95% CI: 11.5-47.2), respectively. The pooled prevalence of laslR, algD, algU, ppyR, and pelF genes were 93.6% (95% CI: 88.1-96.6), 91.4% (95% CI: 80.8-96.4), 89.3% (95% CI: 85.2-92.3), 98.7% (95% CI: 96.5-99.6), and 93% (95% CI: 82.7-97.3), respectively. The highest combined antibiotic resistance rates of P. aeruginosa isolates were against piperacillin/tazobactam (90%). This study showed that biofilm formation was higher in multidrug-resistant (MDR) P. aeruginosa than non-MDRs. A significant correlation was observed between biofilm formation and antibiotic resistance in 50% of studies included in this review.

背景与目标： : 耐药微生物如铜绿假单胞菌在医院通过开发生物膜而生长。我们旨在研究从伊朗人的临床样本中分离出的铜绿假单胞菌的生物膜形成和生物膜相关基因的频率及其与抗生素耐药性模式的关联。这项审查是根据系统审查和荟萃分析 (PRISMA) 指南的首选报告项目进行的。我们使用医学主题词 (包括 “铜绿假单胞菌”，“生物膜形成”，“生物膜相关基因”，“抗生素耐药性” 和 “患病率”) 在科学数据库中进行了系统的文献搜索，以获取相关文章从2000年1月1日到2019年3月30日。研究报告了从伊朗患者获得的铜绿假单胞菌中生物膜形成的患病率，生物膜相关基因的频率以及抗生素耐药性模式。使用综合荟萃分析软件进行荟萃分析。生物膜形成的合并速率按86.5% 计算 (95% 置信区间 [CI]: 79-91.6)。强，中度和弱生物膜的组合频率分别为51% (95% CI: 37.4-64.4)，29.2% (95% CI: 20.9-39.1) 和25.4% (95% CI: 11.5-47.2)。laslR，algD，algU，ppyR和pelF基因的合并患病率为93.6% (95% CI: 88.1-96.6)，91.4% (95% CI: 80.8-96.4)，89.3% (95% CI: 85.2-92.3)，98.7% (95% CI: 96.5-99.6)，和93% (95% CI: 82.7-97.3)。铜绿假单胞菌对哌拉西林/他唑巴坦的抗生素耐药率最高 (90%)。这项研究表明，耐多药 (MDR) 铜绿假单胞菌的生物膜形成高于非MDR。在本综述中纳入的50% 研究中，观察到生物膜形成与抗生素耐药性之间存在显着相关性。

BACKGROUND & AIMS: :The fadBA operon in the fatty acid beta-oxidation pathway of P. putida KCTC1639 was blocked to induce a metabolic flux of the intermediates to the biosynthesis of medium chain-length PHA (mcl-PHA). Succinate at 150 mg l(-1) stimulated cell growth and also the biosynthesis of medium chain-length-polyhydroxyalkanoate. pH-stat fed-batch cultivation of the fadA knockout mutant P. putida KCTC1639 was carried out for 60 h, in which mcl-PHA reached 8 g l(-1) with a cell dry weight of 10.3 g l(-1).

背景与目标： : P. putida KCTC1639的脂肪酸 β 氧化途径中的fadBA操纵子被阻断，以诱导中间体的代谢通量进入中等链长PHA (mcl-pha) 的生物合成。150 mg l(-1) 的琥珀酸盐刺激了细胞生长，也刺激了中链长聚羟基链烷酸酯的生物合成。进行fadA敲除突变体P. putida KCTC1639的pH-stat补料分批培养60小时，其中mcl-pha达到8g l(-1)，细胞干重为10.3g l(-1)。

BACKGROUND & AIMS: :The genetic and evolutionary relationship among 2,4-diacetylphloroglucinol (Phl)-producing pseudomonads that protect plants from soil-borne pathogens were investigated by multilocus sequence typing. A total of 65 pseudomonads consisting of 58 Phl-positive biocontrol strains of worldwide origin and seven Phl-negative representatives of characterized Pseudomonas species were compared using 10 housekeeping genes (i.e. rrs, dsbA, gyrB, rpoD, fdxA, recA, rpoB, fusA, rpsL and rpsG). Multilocus sequence typing differentiated 51 strains among 58 Phl-positive pseudomonads and proved to be as discriminative as enterobacterial repetitive intergenic consensus polymerase chain reaction profiling. As phylogenetic trees inferred from each locus were rather incongruent with one another, we derived the topology from all concatenated loci, which led to the identification of six main groups of Phl-producing Pseudomonas spp. Taxonomically, these groups could correspond to at least six different species. Linkage disequilibrium analysis pointed to a rather clonal structure, even when the analysis was restricted to Phl-producing pseudomonads from a same geographic location or a same phylogenetic group. Intragenic recombination was evidenced for gyrB, rpoD and fdxA, but was shown to be a weaker force than mutation in the origin of intragenetic diversity. This is the first multilocus assessment of the phylogeny and population structure of an ecologically important bacterial group involved in plant disease suppression.

背景与目标： : 通过多基因座序列分型研究了产生2,4-二乙酰基间苯三酚 (Phl) 的假单胞菌保护植物免受土壤传播病原体侵害的遗传和进化关系。使用10个管家基因 (即rrs，dsbA，gyrB，rpoD，fdxA，rec，rpoB，fusA，rpsL和rpsG) 比较了总共65个假单胞菌，这些假单胞菌由58个全球来源的Phl阳性生物防治菌株和7个Phl阴性代表组成)。多基因座序列分型在58个Phl阳性假单胞菌中区分了51个菌株，并被证明与肠杆菌重复基因间共有聚合酶链反应分析一样具有歧视性。由于从每个基因座推断出的系统发育树彼此不一致，因此我们从所有串联基因座中得出了拓扑结构，从而鉴定了六个主要的产生Phl的假单胞菌属。从分类学上讲，这些组可以对应于至少六个不同的物种。连锁不平衡分析指向相当克隆的结构，即使该分析仅限于来自相同地理位置或相同系统发育组的产生Phl的假单胞菌。gyrB，rpoD和fdxA证实了基因内重组，但在基因内多样性的起源中显示出比突变弱的力量。这是对涉及植物病害抑制的生态重要细菌组的系统发育和种群结构的首次多位点评估。

BACKGROUND & AIMS: :Staphylococcus aureus has recently overtaken Pseudomonas aeruginosa as the most commonly recognized bacterial pathogen that infects the respiratory tracts of individuals with the genetic disease cystic fibrosis (CF) in the United States. Most studies of S. aureus in CF patient lung infections have focused on a few isolates, often exclusively laboratory-adapted strains, and how they are killed by P. aeruginosa Less is known about the diversity of S. aureus CF patient lung isolates in terms of both their virulence and their interaction with P. aeruginosa To begin to address this gap, we recently sequenced 64 clinical S. aureus isolates and a reference isolate, JE2. Here, we analyzed the antibiotic resistance genotypes, sequence types, clonal complexes, spa types, agr types, and presence/absence of other known virulence factor genes of these isolates. We hypothesized that virulence phenotypes of S. aureus, namely, toxin production and the mucoid phenotype, would be lost in these isolates due to adaptation in the CF patient lung. In contrast to these expectations, we found that most isolates can lyse both rabbit and sheep blood (67.7%) and produce polysaccharide (69.2%), suggesting that these phenotypes were not lost during adaptation to the CF lung. We also identified three distinct phenotypic groups of S. aureus based on their survival in the presence of nonmucoid P. aeruginosa laboratory strain PAO1 and its mucoid derivative. Altogether, our work provides greater insight into the diversity of S. aureus isolates from CF patients, specifically the distribution of important virulence factors and their interaction with P. aeruginosa, all of which have implications in patient health.IMPORTANCEStaphylococcus aureus is now the most frequently detected recognized pathogen in the lungs of individuals who have cystic fibrosis (CF) in the United States, followed closely by Pseudomonas aeruginosa When these pathogens are found to coinfect the CF lung, patients have a significantly worse prognosis. While P. aeruginosa has been rigorously studied in the context of bacterial pathogenesis in CF, less is known about S. aureus Here, we present an in-depth study of 64 S. aureus clinical isolates from CF patients, for which we investigated genetic diversity utilizing whole-genome sequencing, virulence phenotypes, and interactions with P. aeruginosa We found that S. aureus isolated from CF lungs are phylogenetically diverse; most retain known virulence factors and vary in their interactions with P. aeruginosa (i.e., they range from being highly sensitive to P. aeruginosa to completely tolerant to it). Deepening our understanding of how S. aureus responds to its environment and other microbes in the CF lung will enable future development of effective treatments and preventative measures against these formidable infections.

背景与目标： : 金黄色葡萄球菌最近已超过铜绿假单胞菌，成为最常见的细菌病原体，可感染美国遗传病囊性纤维化 (CF) 个体的呼吸道。大多数关于CF患者肺部感染中金黄色葡萄球菌的研究都集中在少数分离株上，通常是完全实验室适应的菌株，而它们是如何被铜绿假单胞菌杀死的，对金黄色葡萄球菌CF患者肺分离株的多样性了解甚少，因为它们的毒力以及它们与铜绿假单胞菌的相互作用为了开始解决这一差距，我们最近对64个临床金黄色葡萄球菌分离株和一个参考分离株je2进行了测序。在这里，我们分析了这些分离株的抗生素抗性基因型，序列类型，克隆复合物，spa类型，agr类型以及存在/不存在其他已知的毒力因子基因。我们假设，由于CF患者肺部的适应，这些分离株中金黄色葡萄球菌的毒力表型 (即毒素产生和粘液表型) 将丢失。与这些期望相反，我们发现大多数分离株可以裂解兔和绵羊的血液 (67.7%) 并产生多糖 (69.2%)，这表明这些表型在适应CF肺期间没有丢失。我们还根据金黄色葡萄球菌在非粘液样铜绿假单胞菌实验室菌株PAO1及其粘液衍生物的存在下的存活情况，确定了三个不同的表型组。总之，我们的工作为CF患者金黄色葡萄球菌的多样性提供了更深入的了解，特别是重要毒力因子的分布及其与铜绿假单胞菌的相互作用，所有这些都对患者的健康有影响。在美国，金黄色葡萄球菌是目前在患有囊性纤维化 (CF) 的个体中肺部最常被发现的病原体，其次是铜绿假单胞菌。当发现这些病原体同时感染CF肺时，患者的预后明显较差。虽然铜绿假单胞菌在CF的细菌发病机制中进行了严格的研究，但对金黄色葡萄球菌知之甚少，但我们对来自CF患者的64种金黄色葡萄球菌临床分离株进行了深入研究，我们利用全基因组测序，毒力表型，以及与铜绿假单胞菌的相互作用我们发现，从CF肺中分离出的金黄色葡萄球菌在系统发育上是多种多样的; 大多数保留了已知的毒力因子，并且它们与铜绿假单胞菌的相互作用有所不同 (即，它们的范围从对铜绿假单胞菌高度敏感到对其完全耐受)。加深我们对金黄色葡萄球菌对CF肺中的环境和其他微生物的反应的理解，将有助于未来针对这些可怕感染的有效治疗和预防措施的发展。