The restricted number of antibiotics to treat infections caused by common multidrug resistant bacterial pathogens in the clinical setting demands a continuous search for new molecules with antibacterial properties. Bacterial iron deprivation represents a promising alternative, being iron chelators an attractive class for drug design in which particular compounds seem to have antibacterial effect.

In this work, we report the synthesis and characterization of a new fluorescent 3-hydroxy-4-pyridinone (3,4-HPO) iron chelator functionalized with a carboxyrosamine fluorophore (MRB20). The antibacterial activity of MRB20 was assessed against representative strains from clinically relevant Gram-positive and Gram-negative bacterial species and further compared with the inhibitory effect of a set of structurally related iron chelators including Deferiprone (1,2-dimethyl-3-hydroxy-4-pyridinone). Compounds exhibiting a promising minimal inhibitory concentration (MIC < 10 mg/L) were further tested against a wider range of bacterial genera and species (Staphylococcus spp. Enterococcus spp. Listeria monocytogenes, Bacillus spp.), including multidrug resistant bacteria.

With the exception of the novel compound (MRB20), all chelators inhibited the strains assayed at very high concentrations [minimum inhibitory concentrations (MIC) ranging from 70 mg/L to >180 mg/L]. MRB20 revealed a good antibacterial activity (6.7–13.2 mg/L) against Gram-positive strains from different genera and species, including clinically relevant species (Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecium, Enterococcus faecalis), which might be eventually compatible with a therapeutic application or as adjuvant.

在临床环境中，用于治疗由常见的多药耐药细菌病原体引起的感染的抗生素数量有限，需要不断寻找具有抗菌特性的新分子。细菌缺铁是一种有前途的替代方法，是铁螯合剂是药物设计中有吸引力的一类，其中某些化合物似乎具有抗菌作用。

在这项工作中，我们报告了功能化与羧基胺荧光团（MRB20）的新型荧光3-羟基-4-吡啶酮（3,4-HPO）铁螯合剂的合成和表征。评估了MRB20对临床相关革兰氏阳性和革兰氏阴性细菌种类的代表性菌株的抗菌活性，并进一步与一组结构相关的铁螯合剂（包括Deferiprone（1,2-methyl-3-hydroxy- 4-吡啶酮）。表现出有前途的最小抑制浓度化合物（MIC <10毫克/升）进一步对更宽范围的细菌的属和种（的测试葡萄球菌属肠球菌属李斯特菌，芽孢杆菌属 spp。），包括耐多药细菌。

除新型化合物（MRB20）外，所有螯合剂均以极高的浓度[最小抑制浓度（MIC）从70 mg / L至> 180 mg / L]抑制菌株。MRB20对不同属和种的革兰氏阳性菌株（包括临床相关种（金黄色葡萄球菌，表皮葡萄球菌，粪肠球菌，粪肠球菌））表现出良好的抗菌活性（6.7-13.2 mg / L）。治疗性应用或作为佐剂。