MATERIALS AND METHODS: Observational studies were conducted to explore the capacity of nanoparticles to quorum quench wound pathogens.
RESULTS: A review of observational studies indicated that nanoparticles exhibit significant quorum-quenching capabilities against wound pathogens. Numerous nanoparticles, including silver, gold, and zinc oxide, have been demonstrated to inhibit QS-regulated activities, thereby reducing bacterial virulence and biofilm formation. These results suggest that nanoparticles could serve as potent agents for mitigating bacterial infections and enhancing wound healing.
CONCLUSION: Nanoparticles show considerable potential as quorum-quenching agents, effectively decreasing bacterial virulence and biofilm formation in wound pathogens. These results indicate promising applications of nanoparticles in managing bacterial infections and improving wound healing.
AIMS: The aim of this study was to investigate Candida biofilm growth morphology, its biomass, metabolic activity, and to determine the effects of AbA on the biofilm growth.
METHODS: The biofilm forming ability of several clinical isolates of different Candida species from our culture collection was determined using established methods (crystal violet and XTT assays). The determination of AbA planktonic and biofilm MICs was performed based on a micro-broth dilution method. The anti-biofilm effect of AbA on Candida albicans was examined using field emission scanning electron microscope (FESEM) analysis.
RESULTS: A total of 35 (29.7%) of 118 Candida isolates were regarded as biofilm producers in this study. Candida parapsilosis was the largest producer, followed by Candida tropicalis and C. albicans. Two morphological variants of biofilms were identified in our isolates, with 48.6% of the isolates showing mainly yeast and pseudohyphae-like structures, while the remaining ones were predominantly filamentous forms. The biofilm producers were divided into two populations (low and high), based on the ability in producing biomass and their metabolic activity. Candida isolates with filamentous growth, higher biomass and metabolic activity showed lower AbA MIC50 (at least fourfold), compared to those exhibiting yeast morphology, and lower biomass and metabolic activity. The observation of filament detachment and the almost complete removal of biofilm from AbA-treated C. albicans biofilm in FESEM analysis suggests an anti-biofilm effect of AbA.
CONCLUSIONS: The variability in the growth characteristics of Candida biofilm cultures affects susceptibility to AbA, with higher susceptibility noted in biofilm cultures exhibiting filamentous form and high biomass/metabolic activity.
AIM: To determine the susceptibility of A. baumannii isolates to commonly-used biocides, investigate their biofilm-forming capacities and the prevalence of biocide resistance and biofilm-associated genes.
METHODOLOGY: . The minimum inhibitory concentration (MIC) values of 100 A. baumannii hospital isolates from Terengganu, Malaysia, towards the biocides benzalkonium chloride (BZK), benzethonium chloride (BZT) and chlorhexidine digluconate (CLX), were determined by broth microdilution. The isolates were also examined for their ability to form biofilms in 96-well microplates. The prevalence of biocide resistance genes qacA, qacE and qacDE1 and the biofilm-associated genes bap and abaI were determined by polymerase chain reaction (PCR).
RESULTS: Majority of the A. baumannii isolates (43%) showed higher MIC values (> 50 µg/mL) for CLX than for BZK (5% for MIC > 50 µg/mL) and BZT (9% for MIC > 50 µg/mL). The qacDE1 gene was predominant (63%) followed by qacE (28%) whereas no isolate was found harbouring qacA. All isolates were positive for the bap and abaI genes although the biofilm-forming capacity varied among the isolates.
CONCLUSION: The Terengganu A. baumannii isolates showed higher prevalence of qacDE1 compared to qacE although no correlation was found with the biocides' MIC values. No correlation was also observed between the isolates' biofilm-forming capacity and the MIC values for the biocides.