Antibacterial Activity of the Pyrogallol against <i>Staphylococcus aureus</i> Evaluated by Optical Image
Lígia C. C. Oliveira,
Francisco A. A. Rodrigues,
Cristina Rodrigues dos Santos Barbosa,
Joycy Francely Sampaio dos Santos,
Nair Silva Macêdo,
Zildene de Sousa Silveira,
Henrique Douglas Melo Coutinho,
Francisco Assis Bezerra da Cunha
Affiliations
Lígia C. C. Oliveira
Laboratory of Spectroanalytical, Biological and Environmental Chemistry—LEQBA, Department of Biological Chemistry, Regional University of Cariri, Crato 63105-000, Brazil
Francisco A. A. Rodrigues
Science and Technology Center, Universidade Federal do Cariri—UFCA, Juazeiro do Norte 63048-080, Brazil
Cristina Rodrigues dos Santos Barbosa
Laboratory of Bioprospection of Semiarid and Alternative Methods—LABSEMA, Department of Biological Chemistry, Regional University of Cariri, Crato 63105-000, Brazil
Joycy Francely Sampaio dos Santos
Laboratory of Bioprospection of Semiarid and Alternative Methods—LABSEMA, Department of Biological Chemistry, Regional University of Cariri, Crato 63105-000, Brazil
Nair Silva Macêdo
Graduate Program in Biological Sciences, Federal University of Pernambuco, Recife 50670-901, Brazil
Zildene de Sousa Silveira
Graduate Program in Biological Sciences, Federal University of Pernambuco, Recife 50670-901, Brazil
Henrique Douglas Melo Coutinho
Laboratory of Spectroanalytical, Biological and Environmental Chemistry—LEQBA, Department of Biological Chemistry, Regional University of Cariri, Crato 63105-000, Brazil
Francisco Assis Bezerra da Cunha
Laboratory of Bioprospection of Semiarid and Alternative Methods—LABSEMA, Department of Biological Chemistry, Regional University of Cariri, Crato 63105-000, Brazil
The minimum inhibitory concentration (MIC) is used to define the lowest concentration at which a substance can inhibit bacterial growth. This study aimed to evaluate the MIC of pyrogallol against Staphylococcus aureus and to propose a method for building growth inhibition curves of bacterial strains from MIC assays. S. aureus strains 1199B (NorA) and 1199 (wild type) were used for the assays. Pyrogallol MIC tests were performed by the broth microdilution method. The proposed method uses RGB images of the microdilution plate using the R (Red), G (Green), and B (Blue) channels to extract information for the construction of the bacterial growth inhibition curve (GIC). Pyrogallol demonstrated a MIC of 512 µg/mL against the two S. aureus strains tested. The GIC was calculated and the MIC point of pyrogallol was identified against the tested strains. The proposed method suggested the same MIC point for pyrogallol when using microplate images before and after the addition of resazurin. Through this methodology, the subjectivity of visual analysis in MIC tests can be eliminated.
