RESUMO
Pseudomonas aeruginosa is one of the most common pathogenic species associated with canine otitis externa (OE). Their resilience is achieved by forming a biofilm, which allows these bacteria to evade even the harshest of treatments. This study evaluated the in vitro synergistic efficacy of N-acetylcysteine (NAC) with different antimicrobial agents against P. aeruginosa isolated from dogs with OE to develop an effective treatment against P. aeruginosa. The antimicrobial activity was evaluated by the minimum inhibitory concentration test using the microdilution method. The efficacy of antibiofilm formation was evaluated using the crystal violet stain method. The treatment solutions included NAC alone, and in synergy with enrofloxacin, polymyxin B, and gentamicin. NAC alone exhibited antimicrobial and antibiofilm abilities. On the other hand, the combination of NAC and the antibiotics did not show any significant synergistic effects against P. aeruginosa.
RESUMO
Pseudomonas aeruginosa is one of the most common pathogenic species associated with canine otitis externa (OE). Their resilience is achieved by forming a biofilm, which allows these bacteria to evade even the harshest of treatments. This study evaluated the in vitro synergistic efficacy of N-acetylcysteine (NAC) with different antimicrobial agents against P. aeruginosa isolated from dogs with OE to develop an effective treatment against P. aeruginosa. The antimicrobial activity was evaluated by the minimum inhibitory concentration test using the microdilution method. The efficacy of antibiofilm formation was evaluated using the crystal violet stain method. The treatment solutions included NAC alone, and in synergy with enrofloxacin, polymyxin B, and gentamicin. NAC alone exhibited antimicrobial and antibiofilm abilities. On the other hand, the combination of NAC and the antibiotics did not show any significant synergistic effects against P. aeruginosa.
RESUMO
The basidiomycete Laetiporus sulphureus var. miniatus belongs to the Aphyllophorales, Polyporaceae, and grows on the needleleaf tree. The fruiting bodies of Laetiporus species are known to produce N-methylated tyramine derivatives, polysaccharides, and various lanostane triterpenoids. As part of our ongoing effort to discover biologically active compounds from wood-rotting fungi, an anti-inflammatory triterpene, LSM-H7, has been isolated from the fruiting body of L. sulphureus var. miniatus and identified as acetyl eburicoic acid. LSM-H7 dose-dependently inhibited the NO production in RAW 264.7 cells without any cytotoxicity at the tested concentrations. Furthermore it suppressed the production of proinflammatory cytokines, mainly inducible nitric oxide synthase, cyclooxygenase-2, interleukin (IL)-1beta, IL-6 and tumor necrosis factor alpha, when compared with glyceraldehyde 3-phosphate dehydrogenase. These data suggest that LSM-H7 is a crucial component for the anti-inflammatory activity of L. sulphureus var. miniatus.