Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
Sci Total Environ. 2017 Mar 1;581-582:750-755. doi: 10.1016/j.scitotenv.2017.01.003. Epub 2017 Jan 5.
The bacterium Staphylococcus aureus (SA) is known to induce allergic inflammatory responses, including through secreted staphylococcal enterotoxin (SE) superantigens. To quantify indoor environmental exposures to these potential allergens, which may be associated with worse asthma, we developed a method for the assessment of S. aureus and SE in home dust and applied it to a study of homes of inner-city adults with asthma.
We conducted laboratory experiments to optimize sample processing and real-time PCR methods for detection and quantification of SA (femB) and SEA-D, based on published primers. We applied this method to dust and dust extract from 24 homes. We compared results from real-time PCR to culture-based results from the same homes.
The bacteremia DNA isolation method provided higher DNA yield than alternative kits. Culture-based results from homes demonstrated 12 of 24 (50%) bedrooms were contaminated with S. aureus, only one of which carried a SE gene (SEC). In contrast, femB was detected in 23 of 24 (96%) bedrooms with a median of 1.1×10 gene copies detected per gram of raw dust. Prevalence and median copy number (shown in parenthesis) of SE gene detection in bedroom dust was: SEA 25% (1.4×10); SEB 63% (1.4×10); SEC 63% (1.1×10); SED 21% (1.3×10).
Our culture-independent method to detect S. aureus and SE in home dust was more sensitive than our culture-based method. Prevalence of household exposure to S. aureus and SE allergens may be high among adults with asthma.
金黄色葡萄球菌（SA）已知会引起过敏炎症反应，包括通过分泌葡萄球菌肠毒素（SE）超抗原。为了量化室内环境中这些潜在过敏原的暴露情况，这些过敏原可能与更严重的哮喘有关，我们开发了一种评估家庭灰尘中金黄色葡萄球菌和 SE 的方法，并将其应用于一项城市内成年哮喘患者家庭的研究。
我们进行了实验室实验，以优化基于已发表引物的 SA（femB）和 SEA-D 的检测和定量实时 PCR 方法。我们将该方法应用于 24 个家庭的灰尘和灰尘提取物。我们将实时 PCR 的结果与同一家庭的基于培养的结果进行了比较。
血液细菌 DNA 分离法比替代试剂盒提供了更高的 DNA 产量。家庭的基于培养的结果表明，24 个卧室中有 12 个（50%）被金黄色葡萄球菌污染，其中只有一个携带 SE 基因（SEC）。相比之下，femB 在 24 个卧室中的 23 个（96%）中被检测到，每克原始灰尘中检测到的中位数基因拷贝数为 1.1×10。卧室灰尘中 SE 基因检测的流行率和中位数拷贝数（括号内显示）为：SEA 25%（1.4×10）；SEB 63%（1.4×10）；SEC 63%（1.1×10）；SED 21%（1.3×10）。
我们用于检测家庭灰尘中金黄色葡萄球菌和 SE 的非培养方法比我们的基于培养的方法更敏感。哮喘成年人家庭中金黄色葡萄球菌和 SE 过敏原的暴露流行率可能很高。
