RESUMO
Diabetic patients frequently develop wounds, which can be colonized by bacteria, mainly Staphylococcus aureus and Pseudomonas aeruginosa, with the ability to form biofilms. This study aimed to evaluate the colonization and biofilm formation of Staphylococcus aureus and Pseudomonas aeruginosa in chronic wounds of diabetic patients treated with a bioactive dressing (EGF-CMC), which consisted of a 2% carboxymethylcellulose (CMC) hydrogel loaded with epidermal growth factor (EGF). This randomized clinical trial was conducted with 25 participants: 14 treated with EGF-CMC hydrogel and 11 treated with CMC hydrogel for 12 weeks. Participants with type 2 diabetes mellitus were selected. All had diabetic foot ulcers or chronic venous ulcers. Swab collections were performed on weeks 1, 6, and 12. The laboratory analyses included the identification of strains, microbial quantification, virulence gene investigation, and the evaluation of biofilm formation. In total, 13 S. aureus strains and 15 P. aeruginosa strains were isolated. There were no statistically significant differences regarding bacterial loads and virulence genes. However, EGF-CMC-hydrogel-treated wounds were colonized by strains with lower biofilm formation abilities. The probability of isolating biofilm-producing strains from CMC-hydrogel-treated wounds was 83% greater than the probability of isolating biofilm-producing strains from EGF-CMC-treated wounds.
RESUMO
Bromelain is a set of proteolytic enzymes usually obtained from pineapple (Ananas comosus). Although bromelain has distinguished therapeutic properties, little is known about its proteolytic potential against opportunistic pathogens related to wound healing complications, such as Staphylococcus aureus. This study aimed toinvestigate the antibiofilm and antibacterial activity of bromelain in 43 clinical strains of S. aureusisolated from chronic wounds and blood cultures. Bromelain's activity against S. aureusbiofilm in vitrowas assessed by analyzing biofilm formation in cultures grownin the presence of 1% bromelain and biofilm destruction after the addition of 1% bromelain to mature biofilms. Proteinase K and sodium metaperiodate were also added to mature biofilms in parallel to compare their activity with that of bromelain and, together with exopolysaccharide and protein production rate assays, to determine the chemical composition of the biofilm extracellular matrix of selected strains of S. aureus. Bromelain was also evaluated for its DNase activity and impact on cellular hydrophobicity and auto-aggregation. Mueller-Hinton agar dilution was used to determine bromelain minimal inhibitory concentration (MIC). Biofilm assays showed that 1% bromelain significantly inhibits S. aureusbiofilm formation (p= 0.0157) by up to 4-fold and destroys its mature biofilms (p < 0.0001) by up to 6.4-fold, both compared to the control grown without bromelain. Biofilms of methicillin-resistant S. aureusstrains isolated from chronic wounds were the most affected by bromelain treatment. No antibacterial activity was detected with bromelain MIC assays and the proteolytic activity of bromelain was identified as the main antibiofilm mechanism of the enzyme, though its DNase activity may also contribute. The epithelial therapeutic properties of bromelain combined with its antibiofilm activity against S. aureusmake it a promising alternative to compose the therapeutic arsenal for the control of S. aureusbiofilms in the context of wound care.(AU)
Assuntos
Staphylococcus aureus/imunologia , Bromelaínas/análise , BiofilmesRESUMO
OBJECTIVE: The aim of this study was to characterize molecularly multidrug-resistant (MDR) Pseudomonas aeruginosa isolates collected from burn center (BC) patients and environment in a hospital localized in Rio de Janeiro city, RJ, Brazil. METHODS: Thirty-five P. aeruginosa isolates were studied. The antimicrobial resistance was tested by disk diffusion method as recommended by CLSI. The assessment of virulence (exoS and exoU) and resistance (blaPER-1, blaCTX-M, blaOXA-10, blaGES-1, blaVIM, blaIMP, blaSPM-1, blaKPC, blaNDM and blaSIM) genes were achieved through PCR and biofilm forming capacity was determined using a microtiter plates based-assay, as described previously. Genotyping was performed using Multilocus sequence typing (MLST). RESULTS: High rate of P. aeruginosa (71.4%; 25/35) were classified as MDR, of them 64% (16/25) were related to clone A, the most prevalent clone found in the BC studied. A total of eight carbapenems resistant isolates were detected; three belonging to clone A and five carrying the exoU virulence gene. In addition, clone A isolates were also biofilm producers. Two new sequence types (ST) were detected in this study: ST2236, grouped in to clone A; and ST2237, classified in the different clones, displaying carbapenem resistance and exoU virulence gene. CONCLUSION: The high prevalence of biofilm producers and multiresistant P. aeruginosa isolates in BC indicates that prevention programs need to be implemented to avoid infection in highly susceptible patients.