title: Antimicrobial potential of actinobacteria isolated from the rhizosphere of the Caatinga biome plant Caesalpinia pyramidalis Tul.
abstract: Actinobacteria are known to produce various secondary metabolites having antibiotic effects. This study assessed the antimicrobial potential of actinobacteria isolated from the rhizosphere of Caesalpinia pyramidalis Tul. from the Caatinga biome. Sixty-eight actinobacteria isolates were evaluated for antimicrobial activity against different microorganisms by disk diffusion and submerged fermentation, using different culture media, followed by determination of minimum inhibitory concentration (MIC) and chemical prospecting of the crude extract. Of the isolates studied, 52.9% of those isolated at 37°C and 47.05% of those isolated at 45°C had activity against Bacillus subtilis, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Fusarium moniliforme, and Candida albicans. When compared with others actinobacteria, the isolate C1.129 stood out with better activity and was identified by 16S rDNA gene analysis as Streptomyces parvulus. The crude ethanol extract showed an MIC of 0.97 μg/mL for MRSA and B. subtilis, while the ethyl acetate extract showed MIC of 3.9 μg/mL for S. aureus and MRSA, showing the greatest potential among the metabolites produced. Chemical prospecting revealed the presence of mono/sesquiterpenes, proanthocyanidin, triterpenes, and steroids in both crude extracts. This study evaluates S. parvulus activity against multi-resistant microorganisms such as MRSA. Thus, it proves that low-fertility soil, as is found in the Caatinga, may contain important microorganisms for the development of new antimicrobial drugs.
authors.affiliation: Laboratório de Coleção de Microrganismos, Departamento de Antibióticos, Universidade Federal de Pernambuco, Recife, PE, Brasil.
authors.forename: G R
authors.initials: GR
authors.lastname: Silva-Lacerda
authors.affiliation: Laboratório de Coleção de Microrganismos, Departamento de Antibióticos, Universidade Federal de Pernambuco, Recife, PE, Brasil.
authors.forename: R C F
authors.initials: RC
authors.lastname: Santana
authors.affiliation: Laboratório de Coleção de Microrganismos, Departamento de Antibióticos, Universidade Federal de Pernambuco, Recife, PE, Brasil.
authors.forename: M C V
authors.initials: MC
authors.lastname: Vicalvi-Costa
authors.affiliation: Laboratório de Coleção de Microrganismos, Departamento de Antibióticos, Universidade Federal de Pernambuco, Recife, PE, Brasil.
authors.forename: E G
authors.initials: EG
authors.lastname: Solidônio
authors.affiliation: Laboratório de Coleção de Microrganismos, Departamento de Antibióticos, Universidade Federal de Pernambuco, Recife, PE, Brasil.
authors.forename: K X F R
authors.initials: KX
authors.lastname: Sena
authors.affiliation: Laboratório de Coleção de Microrganismos, Departamento de Antibióticos, Universidade Federal de Pernambuco, Recife, PE, Brasil.
authors.forename: G M S
authors.initials: GM
authors.lastname: Lima
authors.affiliation: Laboratório de Coleção de Microrganismos, Departamento de Antibióticos, Universidade Federal de Pernambuco, Recife, PE, Brasil.
authors.forename: J M
authors.initials: JM
authors.lastname: Araújo
mesh_terms: D039903:Actinobacteria / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D000935:Antifungal Agents / Q000737:chemistry / Q000494:pharmacology*; D001412:Bacillus subtilis / Q000187:drug effects; D001688:Biological Products / Q000737:chemistry / Q000494:pharmacology*; D029911:Caesalpinia / Q000382:microbiology*; D002176:Candida albicans / Q000187:drug effects; D005670:Fusarium / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D010802:Phylogeny; D058441:Rhizosphere; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D001688:Biological Products