Fakhoury Asma A, Thompson Thomas P, Rahman Khondaker Miraz, Megaw Julianne, McAteer Matthew I, Skvortsov Timofey, Kelly Stephen A, Gilmore Brendan F
Biofilm Research Group, School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK.
Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, The Hashemite University, Zarqa, Jordan.
NPJ Antimicrob Resist. 2024 Aug 2;2(1):21. doi: 10.1038/s44259-024-00036-5.
Multidrug efflux pumps have been found to play a crucial role in drug resistance in bacteria and eukaryotes. In this study, we investigated the presence of functional multidrug and toxic compound extrusion (MATE) efflux pumps, inferred from whole genome sequencing, in the halophilic archaeon Halorubrum amylolyticum CSM52 using Hoechst 33342 dye accumulation and antimicrobial sensitivity tests in the presence and absence of efflux pump inhibitors (EPIs). The whole genome sequence of H. amylolyticum CSM52 contained two putative MATE-type efflux pump genes, which may contribute to the inherent resistance to conventional antimicrobial agents reported in archaea. Antimicrobial susceptibility of the wild-type H. amylolyticum CSM52 testing revealed a lack of sensitivity to a wide range of antimicrobials, including glycopeptides, aminoglycosides, macrolides, fluoroquinolones, tetracycline, and chloramphenicol. However, the presence of EPIs, such as thioridazine, fluoxetine, and chlorpromazine, significantly increased the susceptibility of H. amylolyticum CSM52 to a number of these antimicrobials, indicating the potential involvement of efflux pumps in the observed resistance. A molecular modelling study with EPIs and substrate antimicrobials provided important insights into the molecular interactions with the putative transporter. It suggests that the occupancy of the transporter channel by EPIs has the potential to impact the efflux of antimicrobials. Phylogenetic analysis of the amino acid sequences of both MATE pumps showed low similarity with bacterial representatives, suggesting the presence of novel and distinct MATE efflux pumps in archaea. Our findings provide the first experimental evidence of active antibiotic efflux mechanisms in archaea and their potential roles in antimicrobial resistance, broadening our understanding of mechanisms of archaeal antimicrobial resistance, an overlooked aspect of AMR research.
多药外排泵已被发现对细菌和真核生物的耐药性起着关键作用。在本研究中，我们使用Hoechst 33342染料积累以及在有和没有外排泵抑制剂（EPI）存在的情况下进行抗菌敏感性测试，通过全基因组测序推断嗜盐古菌解淀粉嗜盐红菌CSM52中功能性多药和有毒化合物外排（MATE）外排泵的存在情况。解淀粉嗜盐红菌CSM52的全基因组序列包含两个假定的MATE型外排泵基因，这可能导致古菌中报道的对传统抗菌剂的固有抗性。野生型解淀粉嗜盐红菌CSM52的抗菌药敏试验表明，它对多种抗菌剂不敏感，包括糖肽类、氨基糖苷类、大环内酯类、氟喹诺酮类、四环素和氯霉素。然而，硫利达嗪、氟西汀和氯丙嗪等EPI的存在显著增加了解淀粉嗜盐红菌CSM52对其中多种抗菌剂的敏感性，表明外排泵可能参与了观察到的耐药性。一项关于EPI和底物抗菌剂的分子建模研究为与假定转运蛋白的分子相互作用提供了重要见解。这表明EPI占据转运蛋白通道有可能影响抗菌剂的外排。对两个MATE泵氨基酸序列的系统发育分析显示与细菌代表的相似性较低，表明古菌中存在新型且独特的MATE外排泵。我们的研究结果首次提供了古菌中主动抗生素外排机制及其在抗菌耐药性中潜在作用的实验证据，拓宽了我们对古菌抗菌耐药性机制的理解，这是抗菌药物耐药性研究中一个被忽视的方面。
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