In this study, fluconazole(FLZ) loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles(NPs) were prepared with two different formulations consisting of polyvinyl alcohol(PVA) and PVA-rhamnolipid(R) in order to improve antibiofilm activity against Candida albicans ATCC 90028. The encapsulation efficiency, drug loading capacity, in-vitro release, characterization and antibiofilm activity of these formulations were compared. Characterization of NPs were analyzed by scanning electron microscopy(SEM) and Zetasizer. Drug loading capacity and encapsulation efficiency percentages were measured by spectrophotometric method. PLGA-NPs were spherical in shape with mean sizes of ~300 nm and surface charge of FLZ loaded PVA and PVA-R-PLGA NPs -25,9±1.99, -48,1±2.46, respectively. Sustained release of FLZ (≥60% after 6 h) were obtained in PVA-R PLGA-NPs. The encapsulation efficiency percentages of PVA-FLZ-PLGA and PVA-R-FLZ-PLGA were 50% and %85 respectively. Antibiofilm inhibition percentages are 55% and 63% respectively. These results show that the PVA-R-FLZ-PLGA drug delivery system is a new therapeutic approach that can be used in infections caused by C.albicans.

In this article, nisin(N)-loaded poly lactic-co-glycolic acid (PLGA) nanoparticles (NPs) were prepared using the single-solvent evaporation method with a rhamnolipid(R) cosurfactant. The antibacterial–antibiofilm effects of the prepared formulation and free nisin were evaluated against S. aureus (ATCC 25923). The characterization of NPs was analyzed using scanning electron microscopy (SEM), Zetasizer and Fourier-transform infrared spectroscopy (FTIR). The drug encapsulation efficiency and loading capacity percentages of NPs were calculated by the spectrophotometric method. The drug release of N-loaded PVA-R-PLGA NPs was determined by the dialysis bag method. The antibacterial and antibiofilm activity of N-PVA-R-PLGA NPs was determined. PVA-R-PLGA-NPs were found to be spherical with sizes of ~140 nm, according to the SEM analysis and surface charge of N-PVA-R-PLGA NPs −53.23 ± 0.42 mV. The sustained release of N (≥72% after 6 h) was measured in PVA-R-PLGA-NPs. The encapsulation efficiency percentage of N-PVA-R-PLGA NP was 78%. The MIC values of free nisin and N-PVA-R-PLGA NPs were 256 μg/mL and 64 μg/mL, respectively. The antibiofilm inhibition percentages of free nisin and N-PVA-R-PLGA NPs were 28% and 72%, respectively. These results reveal that N-PVA-R-PLGA NPs are a promising formulation for use in infections caused by S. aureus compared to free nisin.

This study was concerned with the screening of antimicrobial products from fungi collected from soil and evalution of their antibiofilm activity. The isolate having antimicrobial and antibiofilm compounds was characterized by the molecular methods and identified as Aspergillus sclerotiorum. A. sclerotiorum was grown in yeast peptone glucose (YPG) medium and extracellular medium was extraction by 1:1 ethyl acetate. Crude extraction characterized through thin layer chromatography (TLC) on silica gel 60 HF254 and was detected five bands. Agar diffusion and TLC overlay assays were done against Gram-positive (Staphylococcus aureus ATCC 25923, meticilin resistance S. aureus (MRSA) and Enterococcus faecalis ATCC 29212) and Gram-negative bacteria (Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853). The most dense band (Rf:0.42) showed the best inhibition zone on TLC overlay. The results showed that the most dense band can potential source for antimicrobial compound. After the most dense band in silica gel was scraped and dissolved ethyl acetate for minimum inhibitory concentration (MIC) determination and crystal violet assay against S. aureus and MRSA. These results indicate that fungi, A. sclerotiorum, isolated from soil was potential source for antimicrobial and antibiofilm compounds.

There is a need to discover new antimicrobial agents due to increasing resistance to antibiotics. Researchers focused on AMPs (antimicrobial polypeptide) for these new agents discovered before antibiotics and did not develop resistance as much as antibiotics. In this study the extracellular proteins from isolate LC3 belonging to Aspergillus were purified for new AMP discovery and then tested for antimicrobial activity against Staphylococcus aureus (ATCC 25923) and Methicillin-resistant Staphylococcus aureus (MRSA). Antimicrobial activity was determined by the trypsin/proteinase K assay, which was polypeptide-based, and it was observed that this protein was a protein of about 11 kDa by gel overlay assay. Then the minimum inhibitory concentration of purified AMP molecule against S. aureus ATCC 25923 and MRSA was 8 µg/ml and 32 µg/ml, respectively and the AMP molecule was confirmed. ITS sequence analysis showed that isolate LC3 was identified as Aspergillus niger, using the Bioedit sequence assembly program, the sequence was deposited with the GenBank database with accession number MK332597. These results indicate that the purified AMP molecule has the potential to be used in infections caused by S. aureus.