Synergistic efficacies of thymoquinone and standard antibiotics against multi-drug resistant isolates

Abstract

The antimicrobial activity, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) of TQ were determined using an agar well diffusion method and broth microdilution assays, and the synergistic effect was evaluated using antibiotics in parallel. The disruptive effect of TQ on bacterial cell membranes was determined using scanning electron microscopy. The antivirulence Original Article properties of TQ, which include adherence and biofilm formation, were also investigated using adherence and biofilm formation assays, respectively. Results: Thymoquinone demonstrated bactericidal efficacy against 4/14 bacterial strains, with MIC range of 1.04-8.3 μg/mL and and MBC range of 10.41-66.66 μg/ mL. Thymoquinone showed synergism against Klebsiella pneumoniae, Staphylococcus epidermidis (American Type Culture Collection 12228), Staphylococcus aureus, and Staphylococcus epidermidis in combination with the tested antibiotics. Thymoquinone inhibited bacterial adhesion by 39%-54%, 48%-68%, and 61%-81% at 0.5 × MIC, 1 × MIC, and 2 × MIC, respectively. The tested bacterial strains significantly inhibited biofilm formation after treatment with various concentrations of TQ for 24 and 48 hours. Conclusion: The combinatory effect of TQ with antimicrobials should be considered when developing new antimicrobial therapy regimens to overcome multidrugresistant.

In Vitro and In Silico Approaches for the Evaluation of Antimicrobial Activity, Time-Kill Kinetics, and Anti-Biofilm Potential of Thymoquinone (2-Methyl-5-propan-2-ylcyclohexa-2,5-diene-1,4-dione) against Selected Human Pathogens

“…MDR microorganisms have become a significant public health concern due to their rapid spread over the past decade. Antimicrobial resistance develops quickly in microorganisms, and most synthetic drugs have adverse effects on the human body [ 8 , 12 ]. Due to the emergence of multi-drug resistance and the lack of new safe antimicrobials, innovative strategies for treating MDR pathogens are needed, with low side effects.…”

“…Thymoquinone (2-methyl-5-propan-2-ylcyclohexa-2,5-diene-1,4-dione; TQ), a principal bioactive phytoconstituent of Nigella sativa essential oil, exhibits a wide range of potential medicinal properties [ 7 ]. Many reports suggested that TQ possesses a range of bioactive properties, including antimicrobial, antiviral, antiparasitic, anticancer, and anti-inflammatory effects [ 7 , 8 , 9 , 10 , 11 , 12 ].…”

Safety and Therapeutic Efficacy of Thymoquinone-Loaded Liposomes against Drug-Sensitive and Drug-Resistant Acinetobacter baumannii

“…Besides, TQ has been shown to inhibit biofilm formation in some pathogenic bacteria, including Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis and Pseudomonas aeruginosa [ 32 ]. A study by Dera et al demonstrated TQ-induced reduction in the extracellular cell wall of bacteria as revealed by electron microscopy [ 33 ]. On the other hand, amoxicillin (AMX) was highly effective against drug-sensitive A. baumannii , but not against drug-resistant A. baumannii as shown by the agar well diffusion, dilution and time-kill studies.…”

Antimicrobial, Immunomodulatory and Anti-Inflammatory Potential of Liposomal Thymoquinone: Implications in the Treatment of Bacterial Pneumonia in Immunocompromised Mice

“…The ability of biofilm formation of A. baumannii depends on its outer membrane protein A (ompA) and pili, which mediate the attachment of the biofilm to the surface [9]. TQ has earlier been shown to inhibit the formation of the biofilm by Listeria monocytogenes, Staphylococcus aureus, Staphylococcus epidermidis, Klebsiella pneumoniae, Shigella flexneri, Candida albicans, and Candida glabrata [21][22][23][24][25]. In agreement with the earlier reports, the results of the present study demonstrated that TQ amazingly inhibited biofilm formation and moreover, it also substantially eradicated the preformed biofilm by A. baumannii.…”