RESUMO
Surface-active compounds (SACs) of microbial origin are an active group of biomolecules with potential use in the formulation of emulsions. In this sense, the present study aimed to isolate and select yeasts from fruits that could produce SACs for essential oil emulsions. The Candida krusei M4CK was isolated from the Byrsonima crassifolia fruit to make SACs. This emulsification activity (E24) was equal to or greater 50% in all carbon sources, such as olive oil, sunflower oil, kerosene, hexane, and hexadecane. E24 followed exponential growth according to the growth phase. The stability of emulsions was maintained over a wide range of temperatures, pH, and salinity. The OMBE4CK (melaleuca essential oil emulsion) had better and more significant inhibitory potential for biofilm reduction formation. In addition, bioemulsifier BE4CK alone on Escherichia coli and Pseudomonas aeruginosa biofilm showed few effective results, while there was a significant eradication for Staphylococcus aureus biofilms. The biofilms formed by S. aureus were eradicated in all concentrations of OMBE4CK. At the same time, the preformed biofilm by E. coli and P. aeruginosa were removed entirely at concentrations of 25 mg/mL, 12.5 mg/mL, and 6.25 mg/mL. The results show that the bioemulsifier BE4CK may represent a new potential for antibiofilm application.
RESUMO
A Staphylococcus aureus isolate (SA01) obtained from bloodstream infection exhibited a remarkable drug resistance profile. In this study, we report the draft genome sequence of S. aureus ST 5 SA01, a multidrug-resistant isolate, and analyzed the genes associated with drug resistance and virulence. The genome sketch of S. aureus ST5 SA01 was sequenced with Illumina and annotated using the Prokka software. Rapid Annotation Subsystem Technology (RAST) was used to verify the gene functions in the genome subsystems. The Comprehensive Antibiotic Resistance Database (CARD) and Virulence Factor Database (VFDB) were used in the analysis. The RAST indicated a contribution of 25 proteins to host adenine, fibronectin-binding protein A (FnbA), and biofilm formation as an intercellular polysaccharide adhesive system (PIA). The MLST indicated that S. aureus ST 5 SA01 belongs to ST5 (CC5). In silico analyses also showed an extensive repertoire of genes associated with toxins, such as LukGH leukocidin, enterotoxins, and superantigen staphylococcal classes (SSL). The 11 genes for antimicrobial resistance in S. aureus ST 5 SA01 showed similarity and identity above ≥ 99% with nucleotide sequences deposited in GenBank. Although studies on ST5 clones in Brazil are scarce, monitoring the clone of S. aureus ST 5 SA01 is essential, as it has become a problem in pediatrics in several countries.
Assuntos
Sepse , Staphylococcus aureus , Criança , Humanos , Staphylococcus aureus/genética , Tipagem de Sequências Multilocus , SoftwareRESUMO
Surface-active compounds (SACs), biomolecules produced by bacteria, yeasts, and filamentous fungi, have interesting properties, such as the ability to interact with surfaces as well as hydrophobic or hydrophilic interfaces. Because of their advantages over other compounds, such as biodegradability, low toxicity, antimicrobial, and healing properties, SACs are attractive targets for research in various applications in medicine. As a result, a growing number of properties related to SAC production have been the subject of scientific research during the past decade, searching for potential future applications in biomedical, pharmaceutical, and therapeutic fields. This review aims to provide a comprehensive understanding of the potential of biosurfactants and emulsifiers as antimicrobials, modulators of virulence factors, anticancer agents, and wound healing agents in the field of biotechnology and biomedicine, to meet the increasing demand for safer medical and pharmacological therapies.
RESUMO
Limosilactobacillus fermentum (ATCC 23271) was originally isolated from the human intestine and has displayed antimicrobial activity, primarily against Candida species. Complete genome sequencing and comparative analyses were performed to elucidate the genetic basis underlying its probiotic potential. The ATCC 23271 genome was found to contain 2,193,335 bp, with 2123 protein-coding sequences. Phylogenetic analysis revealed that the ATCC 23271 strain shares 941 gene clusters with six other probiotic strains of L. fermentum. Putative genes known to confer probiotic properties have been identified in the genome, including genes related to adhesion, tolerance to acidic pH and bile salts, tolerance to oxidative stress, and metabolism and transport of sugars and other compounds. A search for bacteriocin genes revealed a sequence 48% similar to that of enterolysin A, a protein from Enterococcus faecalis. However, in vitro assays confirmed that the strain has inhibitory activity on the growth of Candida species and also interferes with their adhesion to HeLa cells. In silico analyses demonstrated a high probability of the protein with antimicrobial activity. Our data reveal the genome features of L. fermentum ATCC 23271, which may provide insight into its future use given the functional benefits, especially against Candida infections.
RESUMO
Staphylococcus aureus is a notorious human pathogen associated with serious nosocomial and community-acquired infections, such as pneumonia, meningitis, endocarditis, toxic shock syndrome, and sepsis, among others. The objective of this study was to investigate the molecular profile, antimicrobial resistance, and clonal diversity of S. aureus isolated from the bloodstream. The determination of the minimum inhibitory concentration (MIC) of the antimicrobial was performed by an automated method. The presence of several virulence and resistance genes was evaluated by PCR. In addition, multilocus sequence typing (MLST) was used to analyze the clonal diversity of S. aureus. A high resistance to oxacillin (78%), clindamycin (78%), erythromycin (70%), ciprofloxacin (61%), and gentamicin (52%) was observed among the isolates. In most of them, the following virulence genes were detected: hlb (83%), ebpS (61%), icaA (57%), fnbpA (17%), and clfA (13%). Only one isolate carried the pvl gene. MLST analysis identified five new sequence types (STs): 5429, 5430, 5431, 5432, and 5433, as well as another seven-ST5, ST97, ST398, ST101, ST30, ST461, and ST2779-among the remaining strains. These seven STs and the four new STs are clustered in four clonal complexes: CC1, CC2, CC7, and CC17. Phylogenetic analysis showed the genetic relationship of the five new ST strains with another 18 strains. Altogether, these analyses indicate the horizontal transfer acquisition of virulence factor genes and multidrug resistance.
RESUMO
BACKGROUND: Although the most widely accepted mechanism of action for polymyxins is related to bacterial lysis via disruption, we hypothesized that this antimicrobial drug class could have other effects on Pseudomonas aeruginosa planktonic and sessile cells. Little is known regarding oxidative burst and zeta potential (ZP) data associated with the interaction between polymyxin B and P. aeruginosa cells. The present study evaluated endogenous reactive oxygen species (ROS) production and changes in the net charges of biofilm and planktonic cells in response to polymyxin B. RESULTS: Polymyxin B induced concentration-dependent killing at all concentrations tested in planktonic and sessile cells from P. aeruginosa strains. Sublethal concentrations of polymyxin B induced oxidative burst. ROS production was higher in resistant planktonic cells than in biofilm cells but this was not observed for susceptible cells. Moreover, no net surface charge alterations were observed in planktonic cells from a susceptible strain treated with polymyxin B, but a significant increase of ZP was noted in planktonic cells from a resistant strain. CONCLUSION: Oxidative burst generated by planktonic and sessile cells from P. aeruginosa strains against polymyxin B indicates that ROS may have an important role in the mechanism of action of this drug. ZP data revealed that electrostatic interactions of the cationic peptide with the anionic surface of the cells are strain-dependent. Therefore, we suggested that the intracellular effects of polymyxin B should be further investigated to understand polymyxin B-induced stress in P. aeruginosa.