作者要感谢李章、李贤志、阿龙·欣兹和克莱顿·霍尔对这份手稿的编辑帮助。这种检测最初是在达特茅斯盖塞尔医学院乔治·奥图尔的实验室中开发的。Mah博士实验室的研究得到了加拿大自然科学和工程研究理事会和加拿大囊性纤维化研究理事会的资助。

1. MBC-B
<ol><li>
种植生物膜（改编自奥图尔9）。
	<ol>
<li>在 37 °C 的丰富介质中种植野生型兴趣菌株和突变菌株，持续 16 小时。</li>
		<li>将饱和的隔夜培养物 1:100 稀释到新的耐药性检测介质中。 P. aeruginosa 的标准介质是 M63 最小介质，辅以硫酸镁和精氨酸（见 表 1）。这种介质刺激形成更坚固的生物膜。</li>
		<li>在 96 井微蒂特菜中加入每口井稀释 100μl（见 表 1）。由于这些检测通常以三份执行，因此每个菌株应有 24 口井。</li>
		<li>在 37 °C 下孵化微质板 24 小时。</li>
	</ol>
</li>
	<li>
将预制生物膜暴露在抗生素的浓度梯度下
	<ol>
<li>为 7 口井准备 10 倍稀释系列抗生素。示例:对于抗生素托霉素，井中的最终浓度为 0.4、0.2、0.1、0.05、0.025、0.0125 和 0.006 毫克/毫升 5-8。 从25毫克/毫升的库存中，准备10倍稀释4，2，1，0.5，0.25，0.125和0.06毫克/毫升。留在冰上</li>
		<li>使用多通道移液器取出已用的超自然（包含浮游生物细胞）（见表1）。</li>
		<li>在所有油井中加入 90 微升 M63 （Mg/Arg）。</li>
		<li>每10倍抗生素浓度中加入10微克，以达到所需的最终浓度。为每个复制品和菌株添加 10 μl 水（无抗生素控制）到最终井中。</li>
		<li>在 37 °C 下孵化微质板 24 小时。</li>
	</ol>
</li>
	<li>
刷新媒体，并允许活细胞分离。
	<ol>
<li>使用多通道移除已用的超自然（包含浮游生物细胞）。</li>
		<li>在所有油井中加入 115 微升 M63 （Mg/Arg）。</li>
		<li>在 37 °C 下孵化微质板 24 小时。</li>
	</ol>
</li>
	<li>
活细胞的检测。
	<ol>
<li>标记每个 96 井微蒂特板的两个 LB agar 板。</li>
		<li>通过将爪子浸入 100% 乙醇中并将爪子穿过 Bunsen 燃烧器的明火，对多管设备（见 表 1）进行消毒。重复。让爪子稍微冷却一下。使用多管齐下装置，将浮石培养物的~3 μl（通常保留在爪尖上的量）从微蒂特板的每口井转移到LB agar板的表面。</li>
		<li>在37°C下孵化LB agar板16小时。</li>
		<li>通过眼睛识别细菌生长的切口（图1），确定抗生素的杀菌浓度最低。</li>
	</ol>
</li>
</ol>2. MBC-P
<ol><li>
准备细菌菌株
	<ol>
<li>在 37 °C 的丰富介质中种植野生型兴趣菌株和突变菌株，持续 16 小时。</li>
		<li>将饱和的隔夜培养物 1:100 稀释到新的耐药性检测介质中。P. aeruginosa的标准介质是 M63 最小介质，辅以硫酸镁和精氨酸（见表 1）。</li>
		<li>在 96 井微蒂菜中加入每口井稀释 90μl（见表 1）。由于这些检测通常以三份执行，因此每个菌株应有 24 口井。</li>
	</ol>
</li>
	<li>
将浮石细胞暴露在抗生素的浓度梯度上
	<ol>
<li>为 7 口井准备 10 倍稀释系列抗生素。示例:对于抗生素托霉素，井中的最终浓度为 0.032、0.016、0.008、0.004、0.002、0.001 和 0.0005 毫克/毫升。从25毫克/毫升的库存中，准备稀释0.32、0.16、0.08、0.04、0.02、0.01和0.005毫克/毫升。留在冰上</li>
		<li>每10倍抗生素浓度中加入10微克，以达到所需的最终浓度。为每个复制品和菌株添加 10 μl 水（无抗生素控制）到最终井中。</li>
		<li>在 37 °C 下孵化微质板 24 小时。</li>
	</ol>
</li>
	<li>
活细胞的检测。
	<ol>
<li>标记每个 96 井微蒂特板的两个 LB agar 板。</li>
		<li>通过将爪子浸入 100% 乙醇中并将爪子穿过 Bunsen 燃烧器的明火，对多管设备（见 表 1）进行消毒。重复。让爪子稍微冷却一下。使用多管齐下装置，将浮石培养物的~3 μl（通常保留在爪尖上的量）从微蒂特板的每口井转移到LB agar板的表面。</li>
		<li>在37°C下孵化LB agar板16小时。</li>
		<li>通过眼睛识别细菌生长的切断（图2），确定抗生素的细菌浓度最低。</li>
	</ol>
</li>
</ol>

<ol>
	<li>Hoiby, N., Bjarnsholt, T., Givskov, M., Molin, S., Ciofu, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antibiotic+resistance+of+bacterial+biofilms.">Antibiotic resistance of bacterial biofilms.</a> Int. J. Antimicrob. Agents. 35 (4), 322-332 (2010).</li><li>Mah, T. F., O'Toole, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanisms+of+biofilm+resistance+to+antimicrobial+agents.">Mechanisms of biofilm resistance to antimicrobial agents.</a> Trends Microbiol. 9 (1), 34-39 (2001).</li><li>Mah, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biofilm-specific+antibiotic+resistance.">Biofilm-specific antibiotic resistance.</a> Future Microbiol. 7 (9), 1061-1072 (2012).</li><li>Mah, T. F., Pitts, B., Pellock, B., Walker, G. C., Stewart, P. S., O'Toole, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+genetic+basis+for+Pseudomonas+aeruginosa+biofilm+antibiotic+resistance.">A genetic basis for Pseudomonas aeruginosa biofilm antibiotic resistance.</a> Nature. 426 (6964), 306-310 (2003).</li><li>Zhang, L., Mah, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Involvement+of+a+Novel+Efflux+System+in+Biofilm-Specific+Resistance+to+Antibiotics.">The Involvement of a Novel Efflux System in Biofilm-Specific Resistance to Antibiotics.</a> J. Bacteriol. 190 (13), 4447-4452 (2008).</li><li>Zhang, L., Hinz, A. J., Nadeau, J. P., Mah, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pseudomonas+aeruginosa+tssC1+Links+Type+VI+Secretion+and+Biofilm-specific+Antibiotic+Resistance.">Pseudomonas aeruginosa tssC1 Links Type VI Secretion and Biofilm-specific Antibiotic Resistance.</a> J. Bacteriol. 193 (19), 5510-5513 (2011).</li><li>Beaudoin, T., Zhang, L., Hinz, A. J., Parr, C. J., Mah, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Biofilm-Specific+Antibiotic+Resistance+Gene,+ndvB,+is+Important+for+Expression+of+Ethanol+Oxidation+Genes+in+Pseudomonas+aeruginosa+Biofilms.">The Biofilm-Specific Antibiotic Resistance Gene, ndvB, is Important for Expression of Ethanol Oxidation Genes in Pseudomonas aeruginosa Biofilms.</a> J. Bacteriol. 194 (12), 3128-3136 (2012).</li><li>O'Toole, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microtiter+Dish+Biofilm+Formation+Assay.">Microtiter Dish Biofilm Formation Assay.</a> J. Vis. Exp. (47), e2437 (2011).</li><li>Lewis, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multidrug+tolerance+of+biofilms+and+persister+cells.">Multidrug tolerance of biofilms and persister cells.</a> Curr. Top. Microbiol. Immunol. 322, 107-131 (2008).</li><li>Merritt, J. H., Kadouri, D. E., O'Toole, G. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Growing+and+Analyzing+Static+Biofilms.">Growing and Analyzing Static Biofilms.</a> Curr. Protoc. Microbiol. 1, 1B.1.1-1B.1.17 (2005).</li><li>Ramey, B. E., Parsek, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+1.+Growing+and+analyzing+biofilms+in+fermenters.">Chapter 1. Growing and analyzing biofilms in fermenters.</a> Curr. Protoc. Microbiol. 1, 1B.3.1-1B.3.14 (2005).</li></ol>

提交人宣称她没有相互竞争的经济利益。

浮石细胞中的抗生素耐药性被定义为由于细胞的永久变化（如 突变）而增加抗生素的最低抑制浓度 （MIC）。迄今已查明的生物膜特异性抗性或耐受性机制是生物膜中野生类型基因表达的结果。因此，抗药性的经典定义不适用于生物膜。然而，另一组定义已经提出:耐药性机制阻止抗生素进入其目标，而耐受性机制关闭抗生素的目标10。生物膜特异性抗生素耐药性机制包括这两个定义...

抗生素耐药性检测最初是为了检测浮游生物（自由游泳）细菌培养物的耐药性而开发的。由于许多细菌感染涉及生物膜（表面连接细胞），我们有兴趣开发一种检测生物膜特异性抗生素耐药性的方法。然而，大多数抗生素耐药性检测不适合测量生物膜的耐药性。例如，确定最低抑制浓度（MIC）是确定浮石细菌培养物 1抗生素耐药性的黄金标准。这种检测需要将稀释的浮石培养物与稀释系列抗生素混合。 抑制浮石细胞可见生长的抗生素浓度是MIC。由于这种检测依赖于对生长的抑制，根据定义，它不能与生物膜培养物配合使用，这需要检查预生生物膜中细胞的抗生素敏感性。此处描述的 MBC-B 检测结果不是测量生长抑制，而是确定杀死生物膜中已有细胞的抗生素浓度。因此，这种检测旨在模仿已建立的生物膜感染的抗生素治疗，并提供一个更相关的视野 中的细菌抗生素耐药性。
由于生物膜通常比浮石培养物2-4更具抗生素耐药性，因此有必要设计出一种将生物膜的抗生素耐药性与浮石培养物直接相关的方法。因此，这种方法的另一个目标是能够直接比较浮石细胞和生物膜细胞之间的抗生素耐药性水平。此处描述的 MBC-P 和 MBC-B 分析使这一点成为可能，因为细胞是在类似条件下培养的。我们利用这种方法研究了几个对生物膜特异性抗生素耐药性很重要的基因。

<table border="1" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td style="width:160px;">
			1x&#160;M63
			</td>
			<td style="width:160px;">
			
			</td>
			<td style="width:160px;">
			
			</td>
			<td style="width:160px;">
			Prepare as a 5x&#160;M63 stock by dissolving 15g KH2PO4, 35g K2HPO4 and 10g (NH4)2SO4 in 1 L of water. This stock does not need to be autoclaved and can be stored at room temperature.&#160; Dilute 5x&#160;stock 1:5, autoclave, cool, then add the desired components.
			</td>
		</tr>
		<tr>
			<td style="width:160px;">
			KH2PO4
			</td>
			<td style="width:160px;">
			Fisher
			</td>
			<td style="width:160px;">
			P285-500
			</td>
			<td style="width:160px;">
			
			</td>
		</tr>
		<tr>
			<td style="width:160px;">
			K2HPO4
			</td>
			<td style="width:160px;">
			Fisher
			</td>
			<td style="width:160px;">
			P288-500
			</td>
			<td style="width:160px;">
			
			</td>
		</tr>
		<tr>
			<td style="width:160px;">
			(NH4)2SO4
			</td>
			<td style="width:160px;">
			Sigma
			</td>
			<td style="width:160px;">
			A5132
			</td>
			<td style="width:160px;">
			
			</td>
		</tr>
		<tr>
			<td style="width:160px;">
			Magnesium sulfate
			</td>
			<td style="width:160px;">
			Fisher
			</td>
			<td style="width:160px;">
			M63-500
			</td>
			<td style="width:160px;">
			Add to 1 mM final concentration.&#160; Prepare as a 1 M stock in water and autoclave.
			</td>
		</tr>
		<tr>
			<td style="width:160px;">
			Tobramycin
			</td>
			<td style="width:160px;">
			Sigma
			</td>
			<td style="width:160px;">
			
			</td>
			<td style="width:160px;">
			Prepare 50 mg/m&#160;stock. Aliquot and store at -20&#176;C.
			</td>
		</tr>
		<tr>
			<td style="width:160px;">
			Arginine
			</td>
			<td style="width:160px;">
			Sigma
			</td>
			<td style="width:160px;">
			A5131
			</td>
			<td style="width:160px;">
			Add to 0.4% final concentration.&#160; Prepare as a 20% stock in water and filter sterilize.&#160; This alternative carbon/energy source can replace glucose and casamino acids
			</td>
		</tr>
		<tr>
			<td style="width:160px;">
			96-well microtiter plates
			</td>
			<td style="width:160px;">
			Corning
			</td>
			<td style="width:160px;">
			3595
			</td>
			<td style="width:160px;">
			Sterile, flat-bottom, low evaporation
			</td>
		</tr>
		<tr>
			<td style="width:160px;">
			Tranferpette (multichannel pipette)
			</td>
			<td style="width:160px;">
			BrandTech
			</td>
			<td style="width:160px;">
			2703610
			</td>
			<td style="width:160px;">
			8-channel, 20-200 &#956;l
			</td>
		</tr>
		<tr>
			<td style="width:160px;">
			Multiprong device
			</td>
			<td style="width:160px;">
			Dan-Kar
			</td>
			<td style="width:160px;">
			MC48
			</td>
			<td style="width:160px;">
			48 prongs fit into &#189; of a 96-well microtiter plate
			</td>
		</tr>
	</tbody>
</table>

establishing the minimal bactericidal concentration of an antimicrobial agent for planktonic cells (mbc-p) and biofilm cells (mbc-b)

该协议允许浮石和生物膜耐药性之间的直接比较的细菌菌株，可以形成一个生物膜 体外。细菌被接种到96井微质板的井中。在浮游生物检测中，选择的抗菌剂的连续稀释被添加到细菌悬浮剂中。在生物膜检测中，一旦接种，细菌就会在一定的时间内形成生物膜。未连接的细胞从井中去除，媒体补充，并添加选择的抗菌剂的连续稀释。接触抗菌剂后，浮石细胞被检测为生长。对于生物膜检测，媒体刷新了缺乏抗菌剂的新鲜介质，生物膜细胞有留给恢复。生物膜细胞的生存能力在恢复期后被检测。抗菌剂的MBC-P被定义为杀死浮石培养细胞的药物浓度最低。 相比之下，菌株的 MBC-B 通过将预制生物膜暴露在 24 小时内抗菌剂浓度增加的程度来确定。MBC-B 被定义为杀死生物膜中细胞的抗菌剂的最低浓度。

进行了 MBC-P 和 MBC-B 检测，比较了 PA14 野生类型的灵敏度与 PA14 ∆ndvB。托布拉霉素被用作抗生素。结果与步骤 1.4.4（图 1）和步骤 2.3.4（图 2）相对应。PA14 和∆ndvB 接种到 MBC-P 和 MBC-B 三方检测中。在完成 MBC-B 协议的第 1.0-1.4 步和 MBC-P 协议的步骤 2.0-2.3 后，可行单元被镀在 LB agar 板上。细胞左侧显示托布拉霉素（μ?...

Watch this Scientific Journal Video about Establishing the Minimal Bactericidal Concentration of an Antimicrobial Agent for Planktonic Cells MBC-P and Biofilm Cells MBC-B at JoVE.com

Establishing the Minimal Bactericidal Concentration of an Antimicrobial Agent for Planktonic Cells MBC-P and Biofilm Cells MBC-B

该协议允许使用 96 井微蒂板直接比较浮石和生物膜耐药性，以识别细菌菌株 ，从而在体外 形成生物膜。浮游生物或生物膜细菌暴露在首选抗菌剂的连续稀释中。活力被阿加板块的生长所测定。

建立浮星细胞（MBC-P）和生物膜细胞（MBC-B）抗菌剂的最小杀菌浓度

This protocol allows for a direct comparison between planktonic and biofilm resistance for a bacterial strain that can form a biofilm in vitro. Bacteria ...

establishing-minimal-bactericidal-concentration-an-antimicrobial

Research

JoVE Journal

Immunology and Infection

Establishing the Minimal Bactericidal Concentration of an Antimicrobial Agent for Planktonic Cells (MBC-P) and Biofilm Cells (MBC-B)

19.9K 次观看.  University of Ottawa. 该协议允许使用 96 井微蒂板直接比较浮石和生物膜耐药性，以识别细菌菌株 ，从而在体外 形成生物膜。浮游生物或生物膜细菌暴露在首选抗菌剂的连续稀释中。活力被阿加板块的生长所测定。

视频: Establishing the Minimal Bactericidal Concentration of an Antimicrobial Agent for Planktonic Cells MBC-P and Biofilm Cells MBC-B

Pseudomonas aeruginosa and Saccharomyces cerevisiae Biofilm in Flow Cells

Many microbial cells have the ability to form sessile microbial communities defined as biofilms that have altered physiological and pathological properties compared to free living microorganisms. Biofilms in nature are often difficult to investigate and reside under poorly defined conditions1. Using a transparent substratum it is possible to device a system where simple biofilms can be examined in a non-destructive way in real-time: here we demonstrate the assembly and operation of a flow cell model system, for in vitro 3D studies of microbial biofilms generating high reproducibility under well-defined conditions2,3.
The system consists of a flow cell that serves as growth chamber for the biofilm. The flow cell is supplied with nutrients and oxygen from a medium flask via a peristaltic pump and spent medium is collected in a waste container. This construction of the flow system allows a continuous supply of nutrients and administration of e.g. antibiotics with minimal disturbance of the cells grown in the flow chamber. Moreover, the flow conditions within the flow cell allow studies of biofilm exposed to shear stress. A bubble trapping device confines air bubbles from the tubing which otherwise could disrupt the biofilm structure in the flow cell.
The flow cell system is compatible with Confocal Laser Scanning Microscopy (CLSM) and can thereby provide highly detailed 3D information about developing microbial biofilms. Cells in the biofilm can be labeled with fluorescent probes or proteins compatible with CLSM analysis. This enables online visualization and allows investigation of niches in the developing biofilm. Microbial interrelationship, investigation of antimicrobial agents or the expression of specific genes, are of the many experimental setups that can be investigated in the flow cell system.

Pseudomonas aeruginosa and Saccharomyces cerevisiae Biofilm in Flow Cells

Protocol describing the application of a flow cell system for growing and analyzing microbial biofilms for Confocal Laser Scanning Microscopy (CLSM).

铜绿假单胞菌和酿酒酵母流细胞生物膜

Many microbial cells have the ability to form sessile microbial communities defined as biofilms that have altered physiological and pathological ...

科研

免疫与感染

In vitro Biofilm Formation in an 8-well Chamber Slide

The chronic nature of many diseases is attributed to the formation of bacterial biofilms which are recalcitrant to traditional antibiotic therapy. Biofilms are community-associated bacteria attached to a surface and encased in a matrix. The role of the extracellular matrix is multifaceted, including facilitating nutrient acquisition, and offers significant protection against environmental stresses (e.g. host immune responses). In an effort to acquire a better understanding as to how the bacteria within a biofilm respond to environmental stresses we have used a protocol wherein we visualize bacterial biofilms which have formed in an 8-well chamber slide. The biofilms were stained with the BacLight Live/Dead stain and examined using a confocal microscope to characterize the relative biofilm size, and structure under varying incubation conditions. Z-stack images were collected via confocal microscopy and analyzed by COMSTAT. This protocol can be used to help elucidate the mechanism and kinetics by which biofilms form, as well as identify components that are important to biofilm structure and stability.

In vitro Biofilm Formation in an 8-well Chamber Slide

This article describes the procedure for the formation and visualization of a bacterial biofilm grown within an 8-well chamber slide

在体外生物膜的形成以及8商会幻灯片

The chronic nature of many diseases is attributed to the formation of bacterial biofilms which are recalcitrant to traditional antibiotic therapy. ...

Following Cell-fate in E. coli After Infection by Phage Lambda

The system comprising bacteriophage (phage) lambda and the bacterium E. coli has long served as a paradigm for cell-fate determination1,2. Following the simultaneous infection of the cell by a number of phages, one of two pathways is chosen: lytic (virulent) or lysogenic (dormant)3,4. We recently developed a method for fluorescently labeling individual phages, and were able to examine the post-infection decision in real-time under the microscope, at the level of individual phages and cells5. Here, we describe the full procedure for performing the infection experiments described in our earlier work5. This includes the creation of fluorescent phages, infection of the cells, imaging under the microscope and data analysis. The fluorescent phage is a "hybrid", co-expressing wild- type and YFP-fusion versions of the capsid gpD protein. A crude phage lysate is first obtained by inducing a lysogen of the gpD-EYFP (Enhanced Yellow Fluorescent Protein) phage, harboring a plasmid expressing wild type gpD. A series of purification steps are then performed, followed by DAPI-labeling and imaging under the microscope. This is done in order to verify the uniformity, DNA packaging efficiency, fluorescence signal and structural stability of the phage stock. The initial adsorption of phages to bacteria is performed on ice, then followed by a short incubation at 35&deg;C to trigger viral DNA injection6. The phage/bacteria mixture is then moved to the surface of a thin nutrient agar slab, covered with a coverslip and imaged under an epifluorescence microscope. The post-infection process is followed for 4 hr, at 10 min interval. Multiple stage positions are tracked such that ~100 cell infections can be traced in a single experiment. At each position and time point, images are acquired in the phase-contrast and red and green fluorescent channels. The phase-contrast image is used later for automated cell recognition while the fluorescent channels are used to characterize the infection outcome: production of new fluorescent phages (green) followed by cell lysis, or expression of lysogeny factors (red) followed by resumed cell growth and division. The acquired time-lapse movies are processed using a combination of manual and automated methods. Data analysis results in the identification of infection parameters for each infection event (e.g. number and positions of infecting phages) as well as infection outcome (lysis/lysogeny). Additional parameters can be extracted if desired.

Following Cell-fate in E. coli After Infection by Phage Lambda

This article describes the procedure for preparing a fluorescently-labeled version of bacteriophage lambda, infection of E. coli bacteria, following the infection outcome under the microscope, and analysis of infection results.

在细胞命运<em&gt; E.大肠杆菌</em感染后的噬菌体λ

The system comprising bacteriophage (phage) lambda and the bacterium E. coli has long served as a paradigm for cell-fate determination1,2. Following the ...

Multiplex PCR Assay for Typing of Staphylococcal Cassette Chromosome Mec Types I to V in Methicillin-resistant Staphylococcus aureus

Staphylococcal Cassette Chromosome mec (SCCmec) typing is a very important molecular tool for understanding the epidemiology and clonal strain relatedness of methicillin-resistant Staphylococcus aureus (MRSA), particularly with the emerging outbreaks of community-associated MRSA (CA-MRSA) occurring on a worldwide basis. Traditional PCR typing schemes classify SCCmec by targeting and identifying the individual mec and ccr gene complex types, but require the use of many primer sets and multiple individual PCR experiments. We designed and published a simple multiplex PCR assay for quick-screening of major SCCmec types and subtypes I to V, and later updated it as new sequence information became available. This simple assay targets individual SCCmec types in a single reaction, is easy to interpret and has been extensively used worldwide. However, due to the sophisticated nature of the assay and the large number of primers present in the reaction, there is the potential for difficulties while adapting this assay to individual laboratories. To facilitate the process of establishing a MRSA SCCmec assay, here we demonstrate how to set up our multiplex PCR assay, and discuss some of the vital steps and procedural nuances that make it successful.

Multiplex PCR Assay for Typing of Staphylococcal Cassette Chromosome Mec Types I to V in Methicillin-resistant Staphylococcus aureus

We demonstrate a simple multiplex PCR assay for quick-screening and typing of Staphylococcal Cassette Chromosome mec (SCCmec) types I-V for methicillin-resistant Staphylococcus aureus, and provide some of the vital steps and procedural nuances that make it successful for adapting this assay to individual laboratories.

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Staphylococcal Cassette Chromosome mec (SCCmec) typing  is a very important molecular tool for understanding the epidemiology and  clonal strain ...

Establishment of a High-throughput Setup for Screening Small Molecules That Modulate c-di-GMP Signaling in Pseudomonas aeruginosa

Bacterial resistance to traditional antibiotics has driven research attempts to identify new drug targets in recently discovered regulatory pathways. Regulatory systems that utilize intracellular cyclic di-GMP (c-di-GMP) as a second messenger are one such class of target. c-di-GMP is a signaling molecule found in almost all bacteria that acts to regulate an extensive range of processes including antibiotic resistance, biofilm formation and virulence. The understanding of how c-di-GMP signaling controls aspects of antibiotic resistant biofilm development has suggested approaches whereby alteration of the cellular concentrations of the nucleotide or disruption of these signaling pathways may lead to reduced biofilm formation or increased susceptibility of the biofilms to antibiotics. We describe a simple high-throughput bioreporter protocol, based on green fluorescent protein (GFP), whose expression is under the control of the c-di-GMP responsive promoter cdrA, to rapidly screen for small molecules with the potential to modulate c-di-GMP cellular levels in Pseudomonas aeruginosa (P. aeruginosa). This simple protocol can screen upwards of 3,500 compounds within 48 hours and has the ability to be adapted to multiple microorganisms.

Establishment of a High-throughput Setup for Screening Small Molecules That Modulate c-di-GMP Signaling in Pseudomonas aeruginosa

This article describes the high-throughput assay that has been successfully established to screen large libraries of small molecules for their potential ability to manipulate cellular levels of cyclic di-GMP in Pseudomonas aeruginosa, providing a new powerful tool for antibacterial drug discovery and compound testing.

高通量设置的建立筛选小分子能调节C-二GMP信令<em&gt;绿脓杆菌</em

Bacterial resistance to traditional antibiotics has driven research attempts to identify new drug targets in recently discovered regulatory pathways. ...

Determination of Biofilm Initiation on Virus-infected Cells by Bacteria and Fungi

The study of polymicrobial interactions across the taxonomic kingdoms that include fungi, bacteria and virus have not been previously examined with respect to how viral members of the microbiome affect subsequent microbe interactions with these virus-infected host cells. The co-habitation of virus with bacteria and fungi is principally present on the mucosal surfaces of the oral cavity and genital tract. Mucosal cells, particularly those with persistent chronic or persistent latent viral infections, could have a significant impact on members of the microbiome through virus alteration in number and type of receptors expressed. Modification in host cell membrane architecture would result in altered ability of subsequent members of the normal flora and opportunistic pathogens to initiate the first step in biofilm formation, i.e., adherence. This study describes a method for quantitation and visual examination of HSV&#39;s effect on the initiation of biofilm formation (adherence) of S. aureus and C. albicans.

A method is described herein for the determination of inter-Kingdom association and competition (bacterial and fungal) for adherence to virus-infected HeLa cell monolayers. This protocol can be extended to multiple combinations of prokaryotes, eukaryotes, and viruses.

生物膜启动对病毒感染的细胞测定细菌和真菌

The study of polymicrobial interactions across the taxonomic kingdoms that include fungi, bacteria and virus have not been previously examined with ...

Development and Validation of an Ultrasensitive Single Molecule Array Digital Enzyme-linked Immunosorbent Assay for Human Interferon-&#945;

The main aim of this protocol is to describe the development and validation of an interferon (IFN)-&#945; single molecule array digital Enzyme-Linked ImmunoSorbent Assay (ELISA) assay. This system enables the quantification of human IFN-&#945; protein with unprecedented sensitivity, and with no cross-reactivity for other species of IFN.
The first key step of the protocol is the choice of the antibody pair, followed by the conjugation of the capture antibody to paramagnetic beads, and biotinylation of the detection antibody. Following this step, different parameters such as assay configuration, detector antibody concentration, and buffer composition can be modified until optimum sensitivity is achieved. Finally, specificity and reproducibility of the method are assessed to ensure confidence in the results. Here, we developed an IFN-&#945; single molecule array assay with a limit of detection of 0.69 fg/mL using high-affinity autoantibodies isolated from patients with biallelic mutations in the autoimmune regulator (AIRE) protein causing autoimmune polyendocrinopathy syndrome type 1/autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APS1/APECED). Importantly, these antibodies enabled detection of all 13 IFN-&#945; subtypes.
This new methodology allows the detection and quantification of IFN-&#945; protein in human biological samples at attomolar concentrations for the first time. Such a tool will be highly useful in monitoring the levels of this cytokine in human health and disease states, most particularly infection, autoimmunity, and autoinflammation.

Here we present a protocol to describe the development and validation of a single molecule array digital ELISA assay, which enables the ultra-sensitive detection of all IFN-&#945; subtypes in human samples.

人干扰素α超灵敏单分子阵列数字酶联免疫吸附试验的研制与验证

The main aim of this protocol is to describe the development and validation of an interferon (IFN)-&#945; single molecule array digital Enzyme-Linked ...

Multicolor Flow Cytometry-based Quantification of Mitochondria and Lysosomes in T Cells

T cells utilize different metabolic programs to match their functional needs during differentiation and proliferation. Mitochondria are crucial cellular components responsible for supplying cell energy; however, excess mitochondria also produce reactive oxygen species (ROS) that could cause cell death. Therefore, the number of mitochondria must constantly be adjusted to fit the needs of the cells. This dynamic regulation is achieved in part through the function of lysosomes that remove surplus/damaged organelles and macromolecules. Hence, cellular mitochondrial and lysosomal contents are key indicators to evaluate the metabolic adjustment of cells. With the development of probes for organelles, well-characterized lysosome or mitochondria-specific dyes have become available in various formats to label cellular lysosomes and mitochondria. Multicolor flow cytometry is a common tool to profile cell phenotypes, and has the capability to be integrated with other assays. Here, we present a detailed protocol of how to combine organelle-specific dyes with surface markers staining to measure the amount of lysosomes and mitochondria in different T cell populations on a flow cytometer.

This article illustrates a powerful method to quantify mitochondria or lysosomes in living cells. The combination of lysosome- or mitochondria-specific dyes with fluorescently conjugated antibodies against surface markers allows the quantification of these organelles in mixed cell populations, like primary cells harvested from tissue samples, by using multicolor flow cytometry.

基于多色流式细胞仪的 t 细胞线粒体和溶酶体的定量

T cells utilize different metabolic programs to match their functional needs during differentiation and proliferation. Mitochondria are crucial cellular ...

Production and Characterization of Human Macrophages from Pluripotent Stem Cells

Macrophages are present in most vertebrate tissues and comprise widely dispersed and heterogeneous cell populations with different functions. They are key players in health and disease, acting as phagocytes during immune defense and mediating trophic, maintenance, and repair functions. Although it has been possible to study some of the molecular processes involved in human macrophage function, it has proved difficult to apply genetic engineering techniques to primary human macrophages. This has significantly hampered our ability to interrogate the complex genetic pathways involved in macrophage biology and to generate models for specific disease states. An off-the-shelf source of human macrophages that is amenable to the vast arsenal of genetic manipulation techniques would, therefore, provide a valuable tool in this field. We present an optimized protocol that allows for the generation of macrophages from human induced pluripotent stem cells (iPSCs) in vitro. These iPSC-derived macrophages (iPSC-DMs) express human macrophage cell surface markers, including CD45, 25F9, CD163, and CD169, and our live-cell imaging functional assay demonstrates that they exhibit robust phagocytic activity. Cultured iPSC-DMs can be activated to different&#160;macrophage states that display altered gene expression and phagocytic activity by the addition of LPS and IFNg, IL4, or IL10. Thus, this system provides a platform to generate human macrophages carrying genetic alterations that model specific human disease and a source of cells for drug screening or cell therapy to treat these diseases.

This protocol describes the robust generation of macrophages from human induced pluripotent stem cells, and methods for their subsequent characterization. Cell surface marker expression, gene expression, and functional assays are used to assess the phenotype and function of these iPSC-derived macrophages.

多能干细胞人类巨噬细胞的产生与表征

Macrophages are present in most vertebrate tissues and comprise widely dispersed and heterogeneous cell populations with different functions. They are key ...

Establishing a Porcine Ex Vivo Cornea Model for Studying Drug Treatments against Bacterial Keratitis

When developing novel antimicrobials, the success of animal trials is dependent on accurate extrapolation of antimicrobial efficacy from in vitro tests to animal infections in vivo. The existing in vitro tests typically overestimate antimicrobial efficacy as the presence of host tissue as a diffusion barrier is not accounted for. To overcome this bottleneck, we have developed an ex vivo porcine corneal model of bacterial keratitis using Pseudomonas aeruginosa as a prototypic organism. This article describes the preparation of the porcine cornea and protocol for establishment of the infection. Bespoke glass molds enable straightforward setup of the cornea for infection studies. The model mimics in vivo infection as bacterial proliferation is dependent on the ability of the bacterium to damage corneal tissue. Establishment of infection is verified as an increase in the number of colony forming units assessed via viable plate counts. The results demonstrate that infection can be established in a highly reproducible fashion in the ex vivo corneas using the method described here. The model can be extended in the future to mimic keratitis caused by microorganisms other than P. aeruginosa. The ultimate aim of the model is to investigate the effect of antimicrobial chemotherapy on the progress of bacterial infection in a scenario more representative of in vivo infections. In so doing, the model described here will reduce the use of animals for testing, improve success rates in clinical trials and ultimately enable rapid translation of novel antimicrobials to the clinic.

This article describes a step-by-step protocol to set up an ex vivo porcine model of bacterial keratitis. Pseudomonas aeruginosa is used as a prototypic organism. This innovative model mimics in vivo infection as bacterial proliferation is dependent on the ability of the bacterium to damage corneal tissue.

建立猪外维沃角膜模型研究药物治疗细菌性角膜炎

When developing novel antimicrobials, the success of animal trials is dependent on accurate extrapolation of antimicrobial efficacy from in vitro tests to ...