Ghafari O, Sharifi A, Ahmadi A, Nayeri Fasaei B
Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran.
Department of Pathobiology, Faculty of Veterinary Science, Bu-Ali Sina University, Hamedan, Iran.
Lett Appl Microbiol. 2018 Dec;67(6):564-569. doi: 10.1111/lam.13050. Epub 2018 Oct 14.
Streptococcus pneumoniae (pneumococcus) is recognized as one of the major cause of infections in communities and hospitals. In this study, anti-pneumococcal and anti-efflux pump activity of two medicinal plants (Thymus daenensis and Origanum vulgare) essential oils were evaluated. Checkerboard assay test was performed for investigation of the effects of selected EOs on ciprofloxacin (CIP) and ethidium bromide (EtBr) uptake in pmrA-overexpressed fluoroquinolone-resistant pneumococcus. Using quantitative real-time RT-PCR the PmrA efflux pump gene (pmrA) expression was evaluated following treatment with selected EOs. Gas chromatography-mass spectrometry analysis was performed for identifying the major components of the tested EOs. The minimum inhibitory concentration (MIC) values for pneumococcus isolates were 0·625-2·5 μl ml for T. daenensis and 1·25-5 μl ml for O. vulgare EOs. We confirmed that in all strains T. daenensis and O. vulgare have a total or partial synergistic effects with CIP and EtBr (FICI from 0·14 to 0·75). In other hand MIC/2 concentration of T. daenensis and O. vulgare EOs caused a significant downregulation of pmrA gene (P < 0·05) in seven of eight strains. This study showed that T. daenensis and O. vulgare EOs have strong antimicrobial and anti-efflux pump activity against clinical isolates of S. pneumoniae and might be useful in controlling pneumococcal infections. SIGNIFICANCE AND IMPACT OF THE STUDY: This study introduced Thymus daenensis and Origanum vulgare essential oil as new antibacterial and anti-efflux pump agents against fluoroquinolone-resistant Streptococcus pneumoniae clinical isolates. These findings indicate that combination of these two essential oils with fluoroquinolone antibiotics may provide alternative methods to overcome the fluoroquinolone-resistant S. pneumoniae.
肺炎链球菌（肺炎球菌）被认为是社区和医院感染的主要原因之一。在本研究中，评估了两种药用植物（百里香和牛至）精油的抗肺炎球菌和抗外排泵活性。进行棋盘法试验以研究所选精油对过表达pmrA的耐氟喹诺酮肺炎球菌中环丙沙星（CIP）和溴化乙锭（EtBr）摄取的影响。使用定量实时RT-PCR评估用所选精油处理后PmrA外排泵基因（pmrA）的表达。进行气相色谱 - 质谱分析以鉴定测试精油的主要成分。百里香精油对肺炎球菌分离株的最低抑菌浓度（MIC）值为0·625 - 2·5 μl/ml，牛至精油为1·25 - 5 μl/ml。我们证实，在所有菌株中，百里香和牛至与CIP和EtBr具有完全或部分协同作用（FICI为0·14至0·75）。另一方面，百里香和牛至精油的MIC/2浓度在八个菌株中的七个中导致pmrA基因显著下调（P < 0·05）。本研究表明，百里香和牛至精油对肺炎链球菌临床分离株具有强大的抗菌和抗外排泵活性，可能有助于控制肺炎球菌感染。研究的意义和影响：本研究介绍了百里香和牛至精油作为针对耐氟喹诺酮肺炎链球菌临床分离株的新型抗菌和抗外排泵剂。这些发现表明，这两种精油与氟喹诺酮类抗生素联合使用可能提供克服耐氟喹诺酮肺炎链球菌的替代方法。
