BioVector® USA300 LAC 菌株 / Staphylococcus aureus USA300 LAC Strain

一、 背景与来源说明 / Background & Origin

USA300 LAC（也常写作 USA300-LAC 或 LAC，源自洛杉矶县/Los Angeles County 临床分离株）是社区获得性耐甲氧西林金黄色葡萄球菌（CA-MRSA）最经典、研究最广泛的高毒力代表菌株之一。USA300 克隆系在北美乃至全球引发了大量的皮肤和软组织感染（SSTI）、坏死性肺炎及败血症。LAC 菌株及其基因敲除突变体衍生株（如 LAC $\Delta$pvl、LAC $\Delta$agr）被全球科研实验室广泛用作金黄色葡萄球菌致病机制、宿主免疫逃逸、毒力因子调控以及抗生素/疫苗研发的标准阳性对照菌株。

二、 菌株生物学特征 / Biological Characteristics

• 物种分类 / Taxonomy：金黄色葡萄球菌 (Staphylococcus aureus)

• 生物安全等级 / Biosafety Level：BSL-2（具有耐药性与强毒力，需在 BSL-2 实验室操作）

• 基因型与分型 / Genotype & Typing：

  • MLST 分型：ST8 (Sequence Type 8)

  • SCCmec 类型：携带 SCCmec Type IVa 盒式基因（耐甲氧西林标志）

  • 毒力岛与因子：携带 PVL (Panton-Valentine Leukocidin) 杀白细胞素基因 及 ACME (Arginine Catabolic Mobile Element) 表达盒

• 耐药谱特征 / Resistance Profile：

  • 对 $\beta$-内酰胺类抗生素（苯唑西林 Oxacillin、甲氧西林 Methicillin、氨苄西林等）耐药

  • 对 红霉素 (Erythromycin) 耐药（携带 msrA 或 ermB/C）

  • 通常对万古霉素 (Vancomycin)、达托霉素 (Daptomycin) 及利奈唑胺 (Linezolid) 敏感

• 主要应用 / Key Uses：金黄色葡萄球菌致病机理研究、PVL/α-溶血素 (Hla) 毒力机制、小鼠皮肤/肺部感染模型构建、新型抗菌药物与抗体体内外药效评价

三、 培养条件与保存指南 / Culture & Handling Protocols

1. 常用培养基 / Culture Media

• 液体培养基：TSB (Tryptic Soy Broth) 或 LB 培养基

• 固体平板：TSA (Tryptic Soy Agar) 或 5% 羊血琼脂平板 (Blood Agar)

• 培养条件：37 摄氏度，气相为好氧培养，液体培养需要 200 rpm 震荡

2. 复苏与传代操作 / Recovery & Subculture

1. 从 -80 摄氏度冻存柜中取出 LAC 菌株冻存管，置于冰上。

2. 用无菌接种环挑取少量菌块，划线接种于 TSA 或血琼脂平板上。

3. 37 摄氏度倒置培养 16 至 18 小时，可见金黄/白色圆润、表面光滑且带明显$\beta$-溶血环的单菌落。

4. 挑取单菌落接种至 TSB 液体培养基中，37 摄氏度震荡培养至对数生长期（OD600 约 0.6 至 0.8）。

3. 菌种冻存保存 / Cryopreservation

• 取对数生长期的重悬菌液，加入无菌甘油至终浓度 15% 至 20%。

• 混匀后分装于无菌冻存管中，直接置于 -80 摄氏度 超低温冰箱长期保存。

四、 技术指标简表 / Technical Data Summary

BioVector® Staphylococcus aureus USA300 LAC Strain

1. Background and Origin

USA300 LAC (also designated as USA300-LAC) is a prototypical clinical isolate originating from Los Angeles County. It serves as the primary reference strain for community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA).USA300 lineages are renowned for causing severe skin and soft tissue infections (SSTIs), necrotizing pneumonia, and bacteremia globally. LAC and its genetic deletion mutants (e.g., LAC $\Delta$pvl, LAC $\Delta$agr) are universally used as standard positive controls in staphylococcal pathogenesis, host-pathogen interactions, and drug/vaccine development studies.

2. Biological Characteristics

• Taxonomy:Staphylococcus aureus

• Biosafety Level:BSL-2 (requires containment due to multidrug resistance and virulence)

• Genotype & Molecular Typing:

  • MLST Sequence Type: ST8

  • SCCmec Element:SCCmec Type IVa

  • Virulence Loci:PVL (Panton-Valentine Leukocidin) positive and ACME (Arginine Catabolic Mobile Element) positive

• Antimicrobial Resistance:

  • Resists $\beta$-lactams (Oxacillin, Methicillin, Penicillins) via mecA

  • Resists Erythromycin

  • Typically remains susceptible to Vancomycin, Daptomycin, and Linezolid

• Primary Applications: Molecular pathogenesis, PVL/alpha-hemolysin toxicity assays, murine SSTI/pneumonia models, and in vitro/in vivo efficacy testing of novel therapeutics

3. Culture and Handling Protocols

Growth Media

• Liquid Broth: Tryptic Soy Broth (TSB) or LB Broth

• Solid Media: Tryptic Soy Agar (TSA) or 5 percent Sheep Blood Agar

• Incubation Conditions: Aerobic at 37 degrees Celsius with shaking at 200 rpm for liquid cultures

Reconstitution & Passage Protocol

1. Streak a small freeze-thaw portion from the -80 degrees Celsius stock onto a TSA or blood agar plate.

2. Incubate upside down at 37 degrees Celsius for 16 to 18 hours. Colonies appear golden/white, convex, smooth, and exhibit strong $\beta$-hemolysis.

3. Inoculate a single colony into fresh TSB broth and shake at 37 degrees Celsius to reach the exponential growth phase (OD600 ~ 0.6 to 0.8).

Cryopreservation

• Mix exponential-phase cell suspensions with sterile glycerol to a final concentration of 15 to 20 percent.

• Aliquot into cryovials and store immediately at -80 degrees Celsius.

4. Technical Data Summary

BioVector NTCC质粒载体菌株细胞蛋白抗体基因保藏中心

电话:400-800-2947

工作QQ/微信同号:1843439339

E-mail:BioVector@163.com

网址http://www.biovector.net