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

• Published in: Saudi medical journal Vol. 42; no. 2; pp. 196 - 204
• Main Authors: Dera, Ayed A, Ahmad, Irfan, Rajagopalan, Prasanna, Shahrani, Mesfer Al, Saif, Ahmed, Alshahrani, Mohammad Y, Alraey, Yasser, Alamri, Ahmad M, Alasmari, Sultan, Makkawi, Mohammed, Alkhathami, Ali G, Zaman, Gaffar, Hakami, Abdulrahim, Alhefzi, Razan, Alfhili, Mohammad A
• Format: Journal Article
• Language: English
• Published: Saudi Arabia Saudi Medical Journal 01-02-2021; Prince Sultan Military Medical City (PSMMC)
• Subjects: Acids; Anti-infective agents; Antibiotics; Antimicrobial agents; Bacteria; Bacterial infections; Biofilms; Drug resistance; Drug resistance in microorganisms; E coli; Gram-negative bacteria; Gram-positive bacteria; Health aspects; Original; Penicillin; Pharmacology, Experimental; Quinone; Salmonella; Scanning electron microscopy; Saudi Arabia; thymoquinone; synergism; biofilm formation; antibacterial; adhesion
• ISSN: 0379-5284; 1658-3175
• DOI: 10.15537/SMJ.2021.2.25706

To explore the antibacterial activity of thymoquinone (TQ), a quinone extracted from
.
This study was conducted from May 2019 to March 2020 at the Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Khalid University, Abha, Saudi Arabia. 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 properties of TQ, which include adherence and biofilm formation, were also investigated using adherence and biofilm formation assays, respectively.
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
,
(American Type Culture Collection 12228),
, and
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.
The combinatory effect of TQ with antimicrobials should be considered when developing new antimicrobial therapy regimens to overcome multidrug-resistant.