Faculty of Medicine, Mbarara University of Science and Technology, Mbarara, Uganda.
Epicentre Mbarara Research Centre, Mbarara, Uganda.
BMC Microbiol. 2019 Aug 22;19(1):194. doi: 10.1186/s12866-019-1566-8.
The rise of methicillin-resistant Staphylococcus aureus (MRSA) is a global health concern. Paucity of data on MRSA carriage prevalence and diagnostic methods in resource-limited settings hampers efforts to define the problem and plan an appropriate response. Additionally, high variability in cost and logistical characteristics of MRSA screening methods may impede infection control efforts. We compared the performance of locally-available chromogenic agar BD CHROMagar MRSA II and two PCR-based assays (Hain GenoQuick MRSA and Cepheid Xpert SA Complete) for the detection of asymptomatic MRSA carriage in nasal swabs.
During 2015, we enrolled 500 patients from five hospital wards at a Ugandan regional referral hospital. We found 30% prevalence of methicillin-sensitive Staphylococcus aureus (MSSA) nasal carriage, and 5.4% MRSA nasal carriage prevalence. Compared to a composite reference standard defined as a positive test result on any one of the three assays, Hain GenoQuick MRSA demonstrated the highest sensitivity (96%) followed by direct plating on CHROMagar at (70%), with the lowest sensitivity observed with Xpert SA Complete (52%). Cepheid Xpert provided the most rapid results (< 1 h) but was the most expensive (US $45-50/test). Substantially more labor was required for the Hain GenoQuick MRSA compared to Xpert SA Complete or CHROMagar tests.
MRSA nasal carriage prevalence rates were low, and high diagnostic sensitivity was achieved using Hain GenoQuick MRSA. Chromogenic media had significantly lower sensitivity, but may represent a viable local option given its lower cost compared to PCR-based assays.
耐甲氧西林金黄色葡萄球菌（MRSA）的出现是一个全球性的健康问题。在资源有限的环境中，缺乏关于 MRSA 携带率和诊断方法的数据，这阻碍了对问题的定义和适当应对措施的规划。此外，MRSA 筛查方法在成本和后勤特性方面存在很大差异，这可能会阻碍感染控制工作。我们比较了本地可用的显色琼脂 BD CHROMagar MRSA II 和两种基于 PCR 的检测方法（Hain GenoQuick MRSA 和 Cepheid Xpert SA Complete）在检测无症状性 MRSA 鼻腔携带方面的性能。
在 2015 年期间，我们从乌干达一家地区转诊医院的五个病房招募了 500 名患者。我们发现耐甲氧西林金黄色葡萄球菌（MSSA）鼻腔携带率为 30%，MRSA 鼻腔携带率为 5.4%。与任何三种检测方法之一的阳性检测结果定义的复合参考标准相比，Hain GenoQuick MRSA 的灵敏度最高（96%），其次是直接在 CHROMagar 平板上培养（70%），而 Xpert SA Complete 的灵敏度最低（52%）。Cepheid Xpert 提供了最快的结果（<1 小时），但最昂贵（每测试 45-50 美元）。与 Xpert SA Complete 或 CHROMagar 检测相比，Hain GenoQuick MRSA 需要更多的劳动力。
MRSA 鼻腔携带率较低，使用 Hain GenoQuick MRSA 可实现高诊断灵敏度。显色培养基的灵敏度显著降低，但与基于 PCR 的检测方法相比，其成本较低，可能是一种可行的本地选择。
