A novel mechanism of action of ketoconazole: inhibition of the NorA efflux pump system and biofilm formation in multidrug-resistant Staphylococcus aureus
Rehab M Abd El-Baky,1,2 Tim Sandle,3 James John,4 Gamal El-Din AA Abuo-Rahma,5 Helal F Hetta6,71Department of Microbiology and Immunology, Faculty of Pharmacy, Minia University, Minia 61519, Egypt; 2Microbiology and Immunology Department, Faculty of Pharmacy, Deraya University, Minia 11566, Egypt; 3...
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| Format: | Article |
| Language: | English |
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Dove Medical Press
2019-06-01
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| Series: | Infection and Drug Resistance |
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| Online Access: | https://www.dovepress.com/a-novel-mechanism-of-action-of-ketoconazole-inhibition-of-the-nora-eff-peer-reviewed-article-IDR |
| _version_ | 1819238496732184576 |
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| author | Abd El-Baky RM Sandle T John J Abuo-Rahma GE Hetta HF |
| author_facet | Abd El-Baky RM Sandle T John J Abuo-Rahma GE Hetta HF |
| author_sort | Abd El-Baky RM |
| collection | DOAJ |
| description | Rehab M Abd El-Baky,1,2 Tim Sandle,3 James John,4 Gamal El-Din AA Abuo-Rahma,5 Helal F Hetta6,71Department of Microbiology and Immunology, Faculty of Pharmacy, Minia University, Minia 61519, Egypt; 2Microbiology and Immunology Department, Faculty of Pharmacy, Deraya University, Minia 11566, Egypt; 3School of Health Sciences, Division of Pharmacy & Optometry, University of Manchester, Manchester, UK; 4Sri Ramachandra Medical College and Research Institute, Sri Ramachandra University, Chennai, India; 5Department of Medicinal Chemistry, Faculty of Pharmacy, Minia University, Minia 61519, Egypt; 6Department of Medical Microbiology & Immunology, Faculty of Medicine, Assiut University, Assiut, Egypt; 7Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USABackground: The rapid emergence of antimicrobial resistance among Gram-positive organisms, especially staphylococci, has become a serious clinical challenge. Efflux machinery and biofilm formation are considered two of the main causes of antimicrobial resistance and therapy failure.Aim: Our study aims to evaluate the antibiofilm and efflux pump inhibitory activity of the antifungal ketoconazole against multidrug-resistant (MDR) Staphylococcus aureus.Methods: Ketoconazole was tested for its effect on the following: minimum inhibitory concentrations (MICs) of ciprofloxacin, norfloxacin, levofloxacin, and ethidium bromide (EtBr) by the broth microdilution method, the efflux of EtBr by NorA-positive MDR S. aureus, and the relative expression of NorA, NorB, and NorC efflux pump genes. Docking studies of ketoconazole were performed using 1PW4 (glycerol-3-phosphate transporter from Escherichia coli which was the representative structure from the major facilitator superfamily).Results: Ketoconazole significantly decreased the MICs of levofloxacin, ciprofloxacin, norfloxacin, and EtBr (a substrate for efflux pump) by 8 to 1024-fold (P<0.01) and decreased the efflux of EtBr. Furthermore, a time-kill assay revealed that combinations of levofloxacin with ketoconazole or carbonyl cyanide m-chlorophenylhydrazone showed no growth for the tested strains after 24 h in comparison to the effect of levofloxacin alone. Docking studies and the ability of ketoconazole to diminish the relative expression of NorA gene in comparison to control (untreated strains) confirmed its action as an efflux pump inhibitor. Conclusion: The findings showed that the antifungal ketoconazole has no antibacterial activity but can potentiate the activity of the fluroquinolones against MDR S. aureus via inhibiting efflux pump and biofilm formation in vitro.Keywords: ketoconazole, efflux pump, biofilm, Nor genes |
| first_indexed | 2024-12-23T13:37:09Z |
| format | Article |
| id | doaj.art-611818c154c74c33a4c2ffab4552593d |
| institution | Directory Open Access Journal |
| issn | 1178-6973 |
| language | English |
| last_indexed | 2024-12-23T13:37:09Z |
| publishDate | 2019-06-01 |
| publisher | Dove Medical Press |
| record_format | Article |
| series | Infection and Drug Resistance |
| spelling | doaj.art-611818c154c74c33a4c2ffab4552593d2022-12-21T17:44:59ZengDove Medical PressInfection and Drug Resistance1178-69732019-06-01Volume 121703171846450A novel mechanism of action of ketoconazole: inhibition of the NorA efflux pump system and biofilm formation in multidrug-resistant Staphylococcus aureusAbd El-Baky RMSandle TJohn JAbuo-Rahma GEHetta HFRehab M Abd El-Baky,1,2 Tim Sandle,3 James John,4 Gamal El-Din AA Abuo-Rahma,5 Helal F Hetta6,71Department of Microbiology and Immunology, Faculty of Pharmacy, Minia University, Minia 61519, Egypt; 2Microbiology and Immunology Department, Faculty of Pharmacy, Deraya University, Minia 11566, Egypt; 3School of Health Sciences, Division of Pharmacy & Optometry, University of Manchester, Manchester, UK; 4Sri Ramachandra Medical College and Research Institute, Sri Ramachandra University, Chennai, India; 5Department of Medicinal Chemistry, Faculty of Pharmacy, Minia University, Minia 61519, Egypt; 6Department of Medical Microbiology & Immunology, Faculty of Medicine, Assiut University, Assiut, Egypt; 7Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USABackground: The rapid emergence of antimicrobial resistance among Gram-positive organisms, especially staphylococci, has become a serious clinical challenge. Efflux machinery and biofilm formation are considered two of the main causes of antimicrobial resistance and therapy failure.Aim: Our study aims to evaluate the antibiofilm and efflux pump inhibitory activity of the antifungal ketoconazole against multidrug-resistant (MDR) Staphylococcus aureus.Methods: Ketoconazole was tested for its effect on the following: minimum inhibitory concentrations (MICs) of ciprofloxacin, norfloxacin, levofloxacin, and ethidium bromide (EtBr) by the broth microdilution method, the efflux of EtBr by NorA-positive MDR S. aureus, and the relative expression of NorA, NorB, and NorC efflux pump genes. Docking studies of ketoconazole were performed using 1PW4 (glycerol-3-phosphate transporter from Escherichia coli which was the representative structure from the major facilitator superfamily).Results: Ketoconazole significantly decreased the MICs of levofloxacin, ciprofloxacin, norfloxacin, and EtBr (a substrate for efflux pump) by 8 to 1024-fold (P<0.01) and decreased the efflux of EtBr. Furthermore, a time-kill assay revealed that combinations of levofloxacin with ketoconazole or carbonyl cyanide m-chlorophenylhydrazone showed no growth for the tested strains after 24 h in comparison to the effect of levofloxacin alone. Docking studies and the ability of ketoconazole to diminish the relative expression of NorA gene in comparison to control (untreated strains) confirmed its action as an efflux pump inhibitor. Conclusion: The findings showed that the antifungal ketoconazole has no antibacterial activity but can potentiate the activity of the fluroquinolones against MDR S. aureus via inhibiting efflux pump and biofilm formation in vitro.Keywords: ketoconazole, efflux pump, biofilm, Nor geneshttps://www.dovepress.com/a-novel-mechanism-of-action-of-ketoconazole-inhibition-of-the-nora-eff-peer-reviewed-article-IDRKetoconazoleefflux pumpbiofilmNor genes |
| spellingShingle | Abd El-Baky RM Sandle T John J Abuo-Rahma GE Hetta HF A novel mechanism of action of ketoconazole: inhibition of the NorA efflux pump system and biofilm formation in multidrug-resistant Staphylococcus aureus Infection and Drug Resistance Ketoconazole efflux pump biofilm Nor genes |
| title | A novel mechanism of action of ketoconazole: inhibition of the NorA efflux pump system and biofilm formation in multidrug-resistant Staphylococcus aureus |
| title_full | A novel mechanism of action of ketoconazole: inhibition of the NorA efflux pump system and biofilm formation in multidrug-resistant Staphylococcus aureus |
| title_fullStr | A novel mechanism of action of ketoconazole: inhibition of the NorA efflux pump system and biofilm formation in multidrug-resistant Staphylococcus aureus |
| title_full_unstemmed | A novel mechanism of action of ketoconazole: inhibition of the NorA efflux pump system and biofilm formation in multidrug-resistant Staphylococcus aureus |
| title_short | A novel mechanism of action of ketoconazole: inhibition of the NorA efflux pump system and biofilm formation in multidrug-resistant Staphylococcus aureus |
| title_sort | novel mechanism of action of ketoconazole inhibition of the nora efflux pump system and biofilm formation in multidrug resistant staphylococcus aureus |
| topic | Ketoconazole efflux pump biofilm Nor genes |
| url | https://www.dovepress.com/a-novel-mechanism-of-action-of-ketoconazole-inhibition-of-the-nora-eff-peer-reviewed-article-IDR |
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