The NorA efflux pump is one of the most studied efflux systems in Staphylococcus aureus and confers multidrug resistance to a variety of dyes and antimicrobial compounds. Hence, inhibition of the NorA efflux pump might be a viable option for restoring susceptibility to antibiotics like fluoroquinolones. Fluorescent real-time efflux assays are important tools to identify putative efflux pump inhibitors. Nevertheless, the number of available compounds for usage in Staphylococcus aureus is limited. Previously, a 3-dipropyloxacarbocyanine iodide (DiOC₃) efflux assay was published that circumvented problems associated with the usage of ethidium bromide, namely slow efflux and suggested mutagenicity. However, the DiOC₃ assay protocol was cuvette – based and therefore needs to be adapted to the 96-well plate format. Hence, we optimized this assay for usage with 96-well plates. The new assay allows for rapid high-throughput efflux pump inhibitor screening.

NorA 外排泵是金黄色葡萄球菌中研究最多的外排系统之一，并赋予对多种染料和抗菌化合物的多重耐药性。因此，抑制 NorA 外排泵可能是恢复对氟喹诺酮类等抗生素敏感性的可行选择。荧光实时外排检测是识别推定的外排泵抑制剂的重要工具。然而，用于金黄色葡萄球菌的可用化合物的数量是有限的。此前，3-二丙基氧杂碳菁碘化物 (DiOC ₃ ) 外排试验已发表，该试验解决了与使用溴化乙锭相关的问题，即缓慢外排和建议的致突变性。然而，DiOC ₃测定方案是基于比色皿的，因此需要适应 96 孔板格式。因此，我们针对 96 孔板的使用优化了该检测。新的测定允许快速高通量外排泵抑制剂筛选。