ANALYSIS OF THE ANTIMICROBIAL AND ANTI-BIOFILM ACTIVITY OF NATURAL COMPOUNDS AND THEIR ANALOGUES AGAINST STAPHYLOCOCCUS AUREUS ISOLATES
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Date
2022
Authors
Mastoor, Sobia
Nazim, Fizza
Rizwan-ul-Hasan, Syed
Ahmed, Khalid
Khan, Shabnam
Nawazish Ali, Syed
Abidi, Syed Hani
Journal Title
Journal ISSN
Volume Title
Publisher
Molecules
Abstract
Staphylococcus aureus (S. aureus) is one of the most frequent causes of
biofilm-associated infections. With the emergence of antibiotic-resistant, especially methicillinresistant
S. aureus (MRSA), there is an urgent need to discover novel inhibitory compounds against
this clinically important pathogen. In this study, we evaluated the antimicrobial and anti-biofilm
activity of 11 compounds, including phenyl propenes and phenolic aldehydes, eugenol, ferulic
acid, sinapic acid, salicylaldehyde, vanillin, cinnamoyl acid, and aldehydes, against drug-resistant
S. aureus isolates. (2) Methods: Thirty-two clinical S. aureus isolates were obtained from Alkhidmat
Diagnostic Center and Blood Bank, Karachi, Pakistan, and screened for biofilm-forming potential, and
susceptibility/resistance against ciprofloxacin, chloramphenicol, ampicillin, amikacin, cephalothin,
clindamycin, streptomycin, and gentamicin using the Kirby-Bauer disk diffusion method. Subsequently,
5 representative clinical isolates were selected and used to test the antimicrobial and
anti-biofilm potential of 11 compounds using both qualitative and quantitative assays, followed by
qPCR analysis to examine the differences in the expression levels of biofilm-forming genes (ica-A,
fnb-B, clf-A and cna) in treated (with natural compounds and their derivatives) and untreated isolates.
(3) Results: All isolates were found to be multi-drug resistant and dominant biofilm formers. The
individual Minimum Inhibitory Concentration (MIC) of natural compounds and their analogues
ranged from 0.75–160 mg/mL. Furthermore, the compounds, Salicylaldehyde (SALI), Vanillin (VAN),
-methyl-trans-cinnamaldehyde (A-MT), and trans-4-nitrocinnamic acid (T4N) exhibited significant
(15–92%) biofilm inhibition/reduction percentage capacity at the concentration of 1–10 mg/mL. Gene
expression analysis showed that salicylaldehyde, -methyl-trans-cinnamaldehyde, and -bromotrans-
cinnamaldehyde resulted in a significant (p < 0.05) downregulation of the expression of ica-A,
clf -A, and fnb-A genes compared to the untreated resistant isolate. (4) Conclusions: The natural
compounds and their analogues used in this study exhibited significant antimicrobial and anti-biofilm
activity against S. aureus. Biofilms persist as the main concern in clinical settings. These compounds
may serve as potential candidate drug molecules against biofilm forming S. aureus.
Description
Keywords
Type of access: Open Access, Staphylococcus aureus, natural compounds, anti-biofilm, antimicrobial, gene expression
Citation
Mastoor, S., Nazim, F., Rizwan-Ul-Hasan, S., Ahmed, K., Khan, S., Ali, S. N., & Abidi, S. S. R. (2022). Analysis of the Antimicrobial and Anti-Biofilm Activity of Natural Compounds and Their Analogues against Staphylococcus aureus Isolates. Molecules, 27(20), 6874. https://doi.org/10.3390/molecules27206874