Food safety is a fundamental concern for both consumers and the food industry, especially as the numbers of reported cases of food-associated infections continue to increase. Industrial surfaces can ...provide a suitable substrate for the development and persistence of bacterial organized in biofilms that represent a potential source of food contamination. The negative consumer perception of chemical disinfectants has shifted the attention to natural substances, such as plant extracts.
The aim of this study was to investigate the possibility of using the essential oils (EOs) in the fight against S. aureus biofilms. First, the Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), Minimum Biofilm Inhibitory Concentration (MBIC), Minimum Biofilm Eradication Concentration (MBEC) of eleven EOs against S. aureus were determined. Cinnamomum cassia and Salvia officinalis EOs showed the greatest antibacterial properties with 1.25% MIC and MBC, 1.25% MBIC and 2.5% MBEC respectively. Gas Chromatography/Mass Spectrometry analysis revealed cinnamaldehyde (82.66%) and methoxy cinnamaldehyde (10.12%) as the most abundant substances of C. cassia, while cis-thujone (23.90%), camphor (19.22%) and 1.8-cineole (10.62%) of S. officinalis. Three different microemulsions, formulated with C. cassia, S. officinalis or both, were finally tested against S. aureus biofilms in different culture media and growth conditions, causing a >3 logarithmic reductions in S. aureus 24h-old biofilms and desiccated biofilms, and up to 68% of biofilm removal after 90min of exposure. The obtained data suggest the potential use of EOs, alone or in combination, for the formulation of sanitizers as alternative or in support in the disinfection of contaminated surfaces.
•S. aureus biofilm development on food contact surfaces in different culture conditions•Microemulsion as formulation to prepare natural sanitizers EOs-based•EOs-based microemulsions have potential to control S. aureus biofilm in food industry.
The synthetic polymers used to protect artworks from deterioration process can be colonized by the fungi and bacteria responsible for the biodeterioration process. In this study, the susceptibility ...of synthetic polyacrylics and polyurethane resins to microorganisms (Aspergillus niger ATCC 9642, Aureobasidium pullulans ATCC 15233, Chaetomium globosum ATCC 6205, Cladosporium cladosporioides ATCC 16022, Alternaria alternata BC01, Penicillium citrinum LS1 and Pseudomonas aeruginosa ATCC 9027) was investigated. The microbial attack was simulated alone and with a biocide and the related growth was observed up to 21 days for bacteria and 28 days for fungi. The polyacrylic and polyurethane resins were subjected to microbial attack, regardless of the biocide treatment, with a fungal growth from 60% to the complete coverage of the plate surface. Penicillium citrinum showed the greatest adaptation ability and was found in all the examined resins. P. aeruginosa was visible in all the different resins, regardless of the presence of biocide. An environmental scanning electron microscope (ESEM) revealed the presence of fungal conidia and hyphae in the inoculated resins and the Fourier transform IR spectroscopy (FTIR-ATR) indicated chemical transformations in the IR spectra, particularly the hydrolysis of esters, with some differences between the polyacrylic and polyurethane resins, which were probably due to their different chemical features. Overall, our data stress that the chemical, physical and biological deterioration caused by microorganisms capable of degrading synthetic polymers is still a problem in art restoration and that new strategies must be considered to counteract this phenomenon.
Cytolethal distending toxin (CDT) is produced by a range of Gram-negative pathogenic bacteria such as
. CDT represents an important virulence factor that is a heterotrimeric complex composed of CdtA, ...CdtB, and CdtC. CdtA and CdtC constitute regulatory subunits whilst CdtB acts as the catalytic subunit exhibiting phosphatase and DNase activities, resulting in cell cycle arrest and cell death. Extracellular vesicle (EV) secretion is an evolutionarily conserved process that is present throughout all kingdoms. Mammalian EVs play important roles in regular cell-to-cell communications but can also spread pathogen- and host-derived molecules during infections to alter immune responses. Here, we demonstrate that CDT targets the endo-lysosomal compartment, partially evading lysosomal degradation and exploiting unconventional secretion (EV release), which is largely involved in bacterial infections. CDT-like effects are transferred by Caco-2 cells to uninfected heterologous U937 and homologous Caco-2 cells. The journey of EVs derived from CDT-treated Caco-2 cells is associated with both intestinal and myeloid tumour cells. EV release represents the primary route of CDT dissemination, revealing an active toxin as part of the cargo. We demonstrated that bacterial toxins could represent suitable tools in cancer therapy, highlighting both the benefits and limitations. The global cell response involves a moderate induction of apoptosis and autophagic features may play a protective role against toxin-induced cell death. EVs from CDT-treated Caco-2 cells represent reliable CDT carriers, potentially suitable in colorectal cancer treatments. Our data present a potential bacterial-related biotherapeutic supporting a multidrug anticancer protocol.
The antimicrobial activity of the marine bisindole alkaloid 2,2-bis(6-bromo-3-indolyl) ethylamine (
) and related synthetic analogues (compounds
⁻
) against target microorganisms was investigated by ...Minimum Inhibitory Concentration (MIC) determination. Compound
showed the greatest antimicrobial activity with the lowest MIC (8 mg/L) against
,
, and
, while the derivatives exhibited higher MICs values (from 16 to 128 mg/L). Compounds
,
,
, and
, the most active ones, were then tested against
,
,
, and
during biofilms formation as well as on 24 h developed biofilms. The natural alkaloid
inhibited the biofilm formation of all the tested microorganisms up to 82.2% and disaggregated biofilms of
,
,
, and
after 30 min of contact, as assessed by viable plate count and crystal violet (CV) staining (optical density at 570 nm). Synthetic derivatives
,
, and
displayed anti-biofilm activity toward individual bacterial populations. This study highlights the potential of marine bisindole alkaloid
as anti-biofilm agent and shows, through a preliminary structure activity relationship (SAR), the importance of halogens and ethylamine side chain for the antimicrobial and antibiofilm activities of this bisindole series.
A small library of 6-
-sucrose monoester surfactants has been synthesized and tested against various microorganisms. The synthetic procedure involved a modified Mitsunobu reaction, which showed ...improved results compared to those present in the literature (higher yields and larger scope). The antifungal activities of most of these glycolipids were satisfactory. In particular, sucrose palmitoleate (URB1537) showed good activity against Candida albicans ATCC 10231,
spp., and
IDRAH01 (MIC value: 16, 32, 64 µg/mL, respectively), and was further characterized through radical scavenging, anti-inflammatory, and biocompatibility tests. URB1537 has been shown to control the inflammatory response and to have a safe profile.
The aim of this research was to determine the potential probiotic activity of
Lactobacillus
acidophilus
ATCC 4356 against several human
Campylobacter jejuni
isolates. The ability to inhibit the ...pathogen’s growth was evaluated by co-culture experiments as well as by antimicrobial assays with cell-free culture supernatant (CFCS), while interference with adhesion/invasion to intestinal Caco-2 cells was studied by exclusion, competition, and displacement tests. In the co-culture experiments
L. acidophilus
ATCC 4356 strain reduced the growth of
C. jejuni
with variable percentages of inhibition related to the contact time. The CFCS showed inhibitory activity against
C. jejuni
strains, stability to low pH, and thermal treatment and sensitivity to proteinase K and trypsin.
L. acidophilus
ATCC 4356 was able to reduce the adhesion and invasion to Caco-2 cells by most of the human
C. jejuni
strains. Displacement and exclusion mechanisms seem to be the preferred modalities, which caused a significant reduction of adhesion/invasion of pathogens to intestinal cells. The observed inhibitory properties of
L. acidophilus
ATCC 4356 on growth ability and on cells adhesion/invasion of
C. jejuni
may offer potential use of this strain for the management of
Campylobacter
infections.
We report the case of an outdoor deteriorated wooden sculpture of Madonna, completely blackened in the face, and thus suspected of fungal attack. A multi-disciplinary approach, including ...microbiological analysis, molecular biology, and Fourier transform infrared (FT-IR) spectroscopy, was applied to understand the real nature of the observed alteration. FT-IR showed that the blackening was due to the application of a natural terpene resin subjected to alteration over time. The microbiological assay allowed to isolate a particular black fungus that has been recovered in the vegetative phase, growing as the only species adapted to the examined substrate. Basic Local Alignment Search Tool (BLAST) analysis of the ITS (internal transcribed spacer) region sequence identified the fungus (LS31012019) as
Zalaria obscura
, a black yeast belonging to the new genus
Zalaria
, family
Dothideales
. Overall, this study evidenced the importance of a multi-disciplinary approach to understand the real causes of observed deterioration of artworks. More interestingly, the recovery of a strain identified as
Z. obscura
from this type of substrate is never reported in the literature and this finding could offer the possibility to investigate the role of this microorganism in the deterioration process of cultural heritage.
Methicillin resistant Staphylococcus aureus (MRSA) infections represent a major global healthcare problem. Therapeutic options are often limited by the ability of MRSA strains to grow as biofilms on ...medical devices, where antibiotic persistence and resistance is positively selected, leading to recurrent and chronic implant-associated infections. One strategy to circumvent these problems is the co-administration of adjuvants, which may prolong the efficacy of antibiotic treatments, by broadening their spectrum and lowering the required dosage. The marine bisindole alkaloid 2,2-bis(6-bromo-1H-indol-3-yl)ethanamine (1) and its fluorinated analogue (2) were tested for their potential use as antibiotic adjuvants and antibiofilm agents against S. aureus CH 10850 (MRSA) and S. aureus ATCC 29213 (MSSA). Both compounds showed antimicrobial activity and bisindole 2 enabled 256-fold reduction (ΣFICs = 0.5) in the minimum inhibitory concentration (MIC) of oxacillin for the clinical MRSA strain. In addition, these molecules inhibited biofilm formation of S. aureus strains, and compound 2 showed greater eradicating activity on preformed biofilm compared to 1. None of the tested molecules exerted a viable but non-culturable cells (VBNC) inducing effect at their MIC values. Moreover, both compounds exhibited no hemolytic activity and a good stability in plasma, indicating a non-toxic profile, hence, in particular compound 2, a potential for in vivo applications to restore antibiotic treatment against MRSA infections.
As a follow-up to our previous studies on glycolipid surfactants, a new molecule, that is lactose 6′-O-undecylenate (URB1418), was investigated. To this end, a practical synthesis and studies aimed ...at exploring its specific properties were carried out. URB1418 showed antifungal activities against Trichophyton rubrum F2 and Candida albicans ATCC 10231 (MIC 512 μg/mL) and no significant antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa. At the same time, it presented anti-inflammatory properties, as documented by the dose-dependent reduction in LPS-induced NO release in RAW 264.7 cells, while a low antioxidant capacity in the range of concentrations tested (EC50 > 200 µM) was also observed. Moreover, URB1418 offers the advantage of being more stable than the reference polyunsaturated lactose esters and of being synthesized using a “green” procedure, involving an enzymatic method, high yield and low manufacturing cost. For all these reasons and the absence of toxicity (HaCaT cells), the new glycolipid presented herein could be considered an interesting compound for applications in various fields.
Polymeric hydrogels are common dosage forms designed for the topical administration of antimicrobial drugs to treat vaginal infections. One of the major advantages of using chitosan in these ...formulations is related to the intrinsic and broad antimicrobial activity exerted on bacteria and fungi by this natural polymer. Most vaginal yeast infections are caused by the pathogenic fungus
. However, despite the anti-Candida activity towards and strains susceptibility to low molecular weight chitosan being documented, no information is available regarding the antimicrobial efficacy of mixed hydrogels in which chitosan is dispersed in a polymeric matrix. Therefore, the aim of the study is to evaluate the anti-Candida activity against eight different albicans and non-albicans strains of a mixed hydroxypropyl methylcellulose (HPMC)/chitosan hydrogel. Importantly, chitosan was dispersed in HPMC matrix either assembled in nanoparticles or in a monomolecular state to eventually correlate any variation in terms of rheological and mucoadhesive properties, as well as anti-Candida activity, with the chitosan form. Hydrogels containing 1%
/
chitosan, either as free polymer chain or assembled in nanoparticles, showed an improved mucoadhesiveness and an anti-Candida effect against all tested albicans and non-albicans strains. Overall, the results demonstrate the feasibility of preparing HPMC/CS mixed hydrogels intended for the prevention and treatment of Candida infections after vaginal administration.
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