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1.
Int J Mol Sci ; 23(22)2022 Nov 15.
Article in English | MEDLINE | ID: mdl-36430545

ABSTRACT

Zosteric acid (ZA) is a secondary metabolite of the seagrass Zostera marina, with antibiofilm activity against fungi. Information concerning its mechanisms of action is lacking and this limits the development of more potent derivatives based on the same target and activity structure. The aim of this work was to investigate the ZA mode of action by analyzing the metabolic status of Candida albicans biofilm and its protein expression profile upon ZA treatment. Fourier-Transform Infrared Spectroscopy confirmed that ZA modified the metabolomic response of treated cells, showing changes in the spectral regions, mainly related to the protein compartment. Nano Liquid Chromatography-High-Resolution Mass Spectrometry highlighted that 10 proteins were differentially expressed in the C. albicans proteome upon ZA treatment. Proteins involved in the biogenesis, structure and integrity of cell walls as well as adhesion and stable attachment of hyphae were found downregulated, whereas some proteins involved in the stress response were found overexpressed. Additionally, ZA was involved in the modulation of non-DNA-based epigenetic regulatory mechanisms triggered by reactive oxygen species. These results partially clarified the ZA mechanism of action against fungi and provided insight into the major C. albicans pathways responsible for biofilm formation.


Subject(s)
Candida albicans , Proteomics , Biofilms , Sulfuric Acid Esters/pharmacology
2.
Mater Sci Eng C Mater Biol Appl ; 128: 112290, 2021 Sep.
Article in English | MEDLINE | ID: mdl-34474841

ABSTRACT

Antimicrobial Polyvinyl chloride (PVC) was obtained by covalent bonding of zinc oxide nanoparticles, which have gained important achievements in antimicrobial fields because of their auspicious properties. This was achieved by grafting mercaptopropyltrimethoxysilane onto PVC, followed by the growth of zinc oxide nanoparticles covalently bonded on the polymer surface. In this study, the relationship between the physicochemical features of modified-surface PVC and antimicrobial activity on Staphylococcus aureus and Candida albicans was investigated. Zinc oxide with controllable morphologies (rods, rod flowers, and petal flowers) was synthesized on the polymer surface by tuning merely base-type and concentration using a hydrothermal process. The antimicrobial activity was more pronounced for rod flower morphology, because of their differences in microscopic parameters such as specific Zn-polar planes. This work provides an important hint for the safe use of PVC for biomedical devices by the structure surface tuning without injuring polymer bulk properties and a reduced risk of the covalently bonded nanoparticle dispersion in the host and the environment.


Subject(s)
Anti-Infective Agents , Nanoparticles , Zinc Oxide , Polyvinyl Chloride , Staphylococcus aureus , Zinc Oxide/pharmacology
3.
Microorganisms ; 9(2)2021 Feb 02.
Article in English | MEDLINE | ID: mdl-33540602

ABSTRACT

Ribosomal RNA in fungi is encoded by a series of genes and spacers included in a large operon present in 100 tandem repeats, normally in a single locus. The multigene nature of this locus was somehow masked by Sanger sequencing, which produces a single sequence reporting the prevalent nucleotide of each site. The introduction of next generation sequencing led to deeper knowledge of the individual sequences (reads) and therefore of the variants between the same DNA sequences located in different tandem repeats. In this framework, NGS sequencing of the rDNA region was used to elucidate the extent of intra- and inter-genomic variation at both the strain and species level. Specifically, the use of an innovative NGS technique allowed the high-throughput high-depth sequencing of the ITS1-LSU D1/D2 amplicons of 252 strains belonging to four opportunistic yeast species of the genus Candida. Results showed the presence of a large extent of variability among strains and species. These variants were differently distributed throughout the analyzed regions with a higher concentration within the Internally Transcribed Spacer (ITS) region, suggesting that concerted evolution was not able to totally homogenize these sequences. Both the internal variability and the SNPs between strain can be used for a deep typing of the strains and to study their ecology.

4.
Microorganisms ; 8(8)2020 Aug 15.
Article in English | MEDLINE | ID: mdl-32824262

ABSTRACT

Yeast taxonomy was introduced based on the idea that physiological properties would help discriminate species, thus assuming a strong link between physiology and taxonomy. However, the instability of physiological characteristics within species configured them as not ideal markers for species delimitation, shading the importance of physiology and paving the way to the DNA-based taxonomy. The hypothesis of reconnecting taxonomy with specific traits from phylogenies has been successfully explored for Bacteria and Archaea, suggesting that a similar route can be traveled for yeasts. In this framework, thirteen single copy loci were used to investigate the predictability of complex Fourier Transform InfaRed spectroscopy (FTIR) and High-performance Liquid Chromatography-Mass Spectrometry (LC-MS) profiles of the four historical species of the Saccharomyces sensu stricto group, both on resting cells and under short-term ethanol stress. Our data show a significant connection between the taxonomy and physiology of these strains. Eight markers out of the thirteen tested displayed high correlation values with LC-MS profiles of cells in resting condition, confirming the low efficacy of FTIR in the identification of strains of closely related species. Conversely, most genetic markers displayed increasing trends of correlation with FTIR profiles as the ethanol concentration increased, according to their role in the cellular response to different type of stress.

5.
Metabolites ; 10(4)2020 Apr 03.
Article in English | MEDLINE | ID: mdl-32260275

ABSTRACT

In yeast engineering, metabolic burden is often linked to the reprogramming of resources from regular cellular activities to guarantee recombinant protein(s) production. Therefore, growth parameters can be significantly influenced. Two recombinant strains, previously developed by the multiple δ-integration of a glucoamylase in the industrial Saccharomyces cerevisiae 27P, did not display any detectable metabolic burden. In this study, a Fourier Transform InfraRed Spectroscopy (FTIR)-based assay was employed to investigate the effect of δ-integration on yeast strains' tolerance to the increasing ethanol levels typical of the starch-to-ethanol industry. FTIR fingerprint, indeed, offers a holistic view of the metabolome and is a well-established method to assess the stress response of microorganisms. Cell viability and metabolomic fingerprints have been considered as parameters to detecting any physiological and/or metabolomic perturbations. Quite surprisingly, the three strains did not show any difference in cell viability but metabolomic profiles were significantly altered and different when the strains were incubated both with and without ethanol. A LC/MS untargeted workflow was applied to assess the metabolites and pathways mostly involved in these strain-specific ethanol responses, further confirming the FTIR fingerprinting of the parental and recombinant strains. These results indicated that the multiple δ-integration prompted huge metabolomic changes in response to short-term ethanol exposure, calling for deeper metabolomic and genomic insights to understand how and, to what extent, genetic engineering could affect the yeast metabolome.

6.
New Microbiol ; 43(1): 47-50, 2020 Jan.
Article in English | MEDLINE | ID: mdl-31814032

ABSTRACT

A correct, fast, reliable identification method is pivotal in nosocomial environments to guide treatment strategies, whereas misidentification might lead to treatment failure. For routine identifications the Vitek system and CHROMagar are widely used but not always reliable, especially now with an increasing number of new emerging fungal pathogens that need careful identification. Here we describe two cases of candidemia, due to Candida palmioleophila previously misidentified as Candida albicans by using the Vitek2 system and CHROMagar. The first case is a 54-year-old man with an infected ulcer in the lower right limb, treated with a targeted therapy using a central venous catheter (CVC). After two months he developed a CVC-related candidemia MDR identified as C. albicans. The second case is a 2-month-old male baby that was admitted to the neonatal unit with acute respiratory failure due to a severe community-acquired bilateral pneumonia; blood cultures were all positive for C. albicans MDR. The isolated strains where re-identified with Maldi-Tof and DNA sequencing as C. palmioleophila. From the identification point of view, CHROMagar can be clearly misleading, especially because CHROMagar types currently available are not designed to discriminate new emerging species, suggesting that systems other than MALDI-TOF and marker sequencing may be inadequate even for routine identification and could contribute to producing misleading identifications and therapeutically wrong practices, leading to failures and patient death.


Subject(s)
Candida , Candidemia , Microbiological Techniques , Candida/genetics , Candida/isolation & purification , Candida albicans , Candidemia/microbiology , Catheter-Related Infections/microbiology , Central Venous Catheters , DNA, Fungal/genetics , Humans , Infant , Italy , Male , Microbiological Techniques/standards , Middle Aged , Respiratory Insufficiency/microbiology , Sequence Analysis, DNA
7.
Article in English | MEDLINE | ID: mdl-31850332

ABSTRACT

In the lignocellulosic yeast development, metabolic burden relates to redirection of resources from regular cellular activities toward the needs created by recombinant protein production. As a result, growth parameters may be greatly affected. Noteworthy, Saccharomyces cerevisiae M2n[pBKD2-Pccbgl1]-C1, previously developed by multiple δ-integration of the ß-glucosidase BGL3, did not show any detectable metabolic burden. This work aims to test the hypothesis that the metabolic burden and the metabolomic perturbation induced by the δ-integration of a yeast strain, could differ significantly. The engineered strain was evaluated in terms of metabolic performances and metabolomic alterations in different conditions typical of the bioethanol industry. Results indicate that the multiple δ-integration did not affect the ability of the engineered strain to grow on different carbon sources and to tolerate increasing concentrations of ethanol and inhibitory compounds. Conversely, metabolomic profiles were significantly altered both under growing and stressing conditions, indicating a large extent of metabolic reshuffling involved in the maintenance of the metabolic homeostasis. Considering that four copies of BGL3 gene have been integrated without affecting any parental genes or promoter sequences, deeper studies are needed to unveil the mechanisms implied in these metabolomic changes, thus supporting the optimization of protein production in engineered strains.

8.
Pathogens ; 8(3)2019 Aug 29.
Article in English | MEDLINE | ID: mdl-31470609

ABSTRACT

Tuberculins purified protein derivatives (PPDs) are obtained by precipitation from heat treated mycobacteria. PPDs are used in diagnosis of mycobacterial infections in humans and animals. Bovine PPD (PPDB) is obtained from Mycobacterium bovis (Mycobacterium tuberculosis complex), while Avian PPD (PPDA) and Johnin PPD (PPDJ) are extracted, respectively, from Mycobacterium avium and M. avium subsp. paratuberculosis (M. avium complex). PPDB and PPDA are used for bovine tuberculosis diagnosis, while PPDJ is experimentally used in the immunodiagnosis of paratuberculosis. Although PPDs date back to the 19th Century, limited knowledge about their composition is currently available. The goal of our study was to evaluate Fourier Transform InfraRed (FTIR) spectroscopy as a tool to differentiate PPDB, PPDA, and three PPDJs. The results highlighted that the three PPDs have specific profiles, correlated with phylogenetic characteristics of mycobacteria used for their production. This analysis is eligible as a specific tool for different PPDs batches characterization and for the assessment of their composition. The entire PPD production may be efficiently controlled, since the N content of each preparation is related to IR spectra, with a reference spectrum for each PPD and a standardized analysis protocol.

9.
Mater Sci Eng C Mater Biol Appl ; 104: 109977, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31500068

ABSTRACT

Zinc oxide nanoparticles were synthesized using two silica supports largely used in pharmaceutical field as excipients, Cab-O-Sil-H5 and Syloid 244 FP characterized by high surface area and different porosity. In order to evaluate the effects of different silica on nanoparticle chemical physical properties, composites (ZnO-SiO2) containing different amounts of ZnO nanoparticles were obtained and characterized by X-ray Powder Diffraction (XRPD), Transmission Electron Microscopy (TEM), Attenuated Transmission Reflectance (ATR), UV-vis spectroscopy and finally Photoluminescence (PL). Composites showed the presence of quite uniformly distributed zinc nanostructures on the silica surface with size in the range of 30-50 nm with an estimated specific surface area ranged from ca. 20 to 70 m2/g. The formation of a Zn-O-Si interface in ZnO-SiO2 was observed as well. Photoluminescence studies revealed that ZnO-SiO2 samples based on Cab-O-Sil present a higher contribution of oxygen vacancies per unit volume. Finally, the resulting composites were tested for antibacterial and antifungal activities. Whereas silica supports did not show any antibacterial and antifungal activities, most of the prepared composites, both with Cab-O-Sil-5H and Syloid 244 FP supports, resulted active against both bacteria and fungi. In particular the contingency analysis showed that the amount of zinc oxide in the composites was partly related to MIC results in bacteria (p = 0.059), whereas it showed an interesting p = 0.022 in yeast in the case of low amount of ZnO (10%). Thus, the described ZnO-SiO2 composites can be proposed for the preparation of both pharmaceutical formulations and medical disposals with antibacterial and antifungal activities.


Subject(s)
Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Antifungal Agents/chemistry , Antifungal Agents/pharmacology , Nanostructures/chemistry , Silicon Dioxide/chemistry , Zinc Oxide/chemistry , Bacteria/drug effects , Fungi/drug effects , Metal Nanoparticles/chemistry , Microbial Sensitivity Tests/methods , Microscopy, Electron, Scanning/methods , Microscopy, Electron, Transmission/methods , Particle Size , Spectroscopy, Fourier Transform Infrared/methods , X-Ray Diffraction/methods , Zinc/chemistry
10.
Microorganisms ; 7(3)2019 Mar 07.
Article in English | MEDLINE | ID: mdl-30866438

ABSTRACT

Microbes growing onto solid surfaces form complex 3-D biofilm structures characterized by the production of extracellular polymeric compounds and an increased resistance to drugs. The quantification of biofilm relays currently on a number of different approaches and techniques, often leading to different evaluations of the ability to form biofilms of the studied microbial strains. Measures of biofilm biomass were carried out with crystal violet (CV) and a direct reading at 405 nm, whereas the activity was assessed with the XTT ((2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) method. The strains of four pathogenic species of the genus Candida (C. albicans, C. glabrata, C. parapsilosis and C. tropicalis) and of Staphylococcus aureus were employed to determine the effective relatedness among techniques and the specific activity of the biofilm, as a ratio between the XTT and the CV outcomes. Since the ability to form biomass and to be metabolically active are not highly related, their simultaneous use allowed for a categorization of the strains. This classification is putatively amenable of further study by comparing the biofilm type and the medical behavior of the strains.

11.
R Soc Open Sci ; 6(1): 180718, 2019 Jan.
Article in English | MEDLINE | ID: mdl-30800340

ABSTRACT

Lignocellulosic bioethanol production results in huge amounts of stillage, a potentially polluting by-product. Stillage, rich in heavy metals and, mainly, inhibitors, requires specific toxicity studies to be adequately managed. To this purpose, we applied an FTIR ecotoxicological bioassay to evaluate the toxicity of lignocellulosic stillage. Two weak acids and furans, most frequently found in lignocellulosic stillage, have been tested in different mixtures against three Saccharomyces cerevisiae strains. The metabolomic reaction of the test microbes and the mortality induced at various levels of inhibitor concentration showed that the strains are representative of three different types of response. Furthermore, the relationship between concentrations and FTIR synthetic stress indexes has been studied, with the aim of defining a model able to predict the concentrations of inhibitors in stillage, resulting in an optimized predictive model for all the strains. This approach represents a promising tool to support the ecotoxicological management of lignocellulosic stillage.

12.
Microorganisms ; 7(2)2019 Jan 24.
Article in English | MEDLINE | ID: mdl-30682881

ABSTRACT

A procedure for microbial cell density determination with a high-throughput densitometric assay was developed to allow a precise quantification of both free and sessile cells, such as those of a biofilm, with a large range from low to high cell densities. Densitometry was chosen because it allows fast, rapid and cost-effective measures; it is non-disruptive; and has an easy learning curve. The method setup, and the further validation, was carried out with strains of Candida albicans, C. tropicalis and C. parapsilosis. Equations were developed at the level of the single strains, of the three species and finally a general one applicable to all three species. In the cross validation, with strains absent from the training set, the method was shown to be robust and flexible. The best results were obtained with species specific equations, although the global equation performed almost as well in terms of correlation between real and estimated density values. In all cases, a correlation around 0.98 between effective and predicted density was obtained with figures ranging from 10² to 108 cells mL-1. The entire analytical part of the procedure can be accomplished with a MS Excel macro provided free of charge.

13.
Front Microbiol ; 9: 1687, 2018.
Article in English | MEDLINE | ID: mdl-30123190

ABSTRACT

A yeast strain was isolated during a study on vineyard-associated yeast strains from Apulia in Southern Italy. ITS and LSU D1/D2 rDNA sequences showed this strain not to belong to any known species and was described as the type strain of Ogataea uvarum sp. nov., a close relative of O. philodendri. Several secondary peaks appeared in the sequences, suggesting internal heterogeneity among the copies of the rDNA. This hypothesis was tested by sequencing single clones of the marker region. The analyses showed different levels of variability throughout the operon with differences between the rRNA encoding genes and the internally transcribed regions. O. uvarum and O. philodendri share high frequency variants, i.e., variants frequently found in many clones, whereas there is a large variability of the low frequency polymorphisms, suggesting that the mechanism of homogenization is more active with the former than with the latter type of variation. These findings indicate that low frequency variants are detected in Sanger sequencing as secondary peaks whereas in Next Generation Sequencing (NGS) of metagenomics DNA would lead to an overestimate of the alpha diversity. For the first time in our knowledge, this investigation shed light on the variation of the copy number of the rDNA cistron during the yeast speciation process. These polymorphisms can be used to investigate on the processes occurring in these taxonomic markers during the separation of fungal species, it being a genetic process highly frequent in the complex microbial ecosystem existing in grape, must and wine.

14.
IMA Fungus ; 9(1): 91-105, 2018 Jun.
Article in English | MEDLINE | ID: mdl-30018874

ABSTRACT

Species identification of yeasts and other Fungi is currently carried out with Sanger sequences of selected molecular markers, mainly from the ribosomal DNA operon, characterized by hundreds of tandem repeats of the 18S, ITS1, 5.8S, ITS2 and LSU loci. The ITS region has been recently proposed as a primary barcode marker making this region the most used one in taxonomy, phylogeny and diagnostics. The introduction of NGS is providing tools of high efficacy and relatively low cost to amplify two or more markers simultaneously with great sequencing depth. However, the presence of intra-genomic variability between the repeats requires specific analytical procedures and pipelines. In this study, 286 strains belonging to 11 pathogenic yeasts species were analysed with NGS of the region spanning from ITS1 to the D1/D2 domain of the LSU encoding ribosomal DNA. Results showed that relatively high heterogeneity can hamper the use of these sequences for the identification of single strains and even more of complex microbial mixtures. These observations point out that the metagenomics studies could be affected by species inflection at levels higher than currently expected.

15.
Infect Dis Ther ; 7(Suppl 1): 27-34, 2018 Mar.
Article in English | MEDLINE | ID: mdl-29549654

ABSTRACT

Medical and environmental microbiology have two distinct, although very short, histories stemming, the first from the pioneering works of Sommelweiss, Pasteur, Lister and Koch, the second mainly from the studies of Bejerink and Winogradsky. These two branches of microbiology evolved and specialized separately producing distinct communities and evolving rather different approaches and techniques. The evidence accumulated in recent decades indicate that indeed most of the medically relevant microorganisms have a short circulation within the nosocomial environment and a larger one involving the external, i.e. non-nosocomial, and the hospital environments. This evidence suggests that the differences between approaches should yield to a convergent approach aimed at solving the increasing problem represented by infectious diseases for the increasingly less resistant human communities. Microbial biofilm is one of the major systems used by these microbes to resist the harsh conditions of the natural and anthropic environment, and the even worse ones related to medical settings. This paper presents a brief outline of the converging interest of both environmental and medical microbiology toward a better understanding of microbial biofilm and of the various innovative techniques that can be employed to characterize, in a timely and quantitative manner, these complex structures. Among these, micro-Raman along with micro-Brillouin offer high hopes of describing biofilms both at the subcellular and supercellular level, with the possibility of characterizing the various landscapes of the different biofilms. The possibility of adding a taxonomic identification of the cells comprising the biofilm is a complex aspect presenting several technical issues that will require further studies in the years to come.

16.
PLoS One ; 12(12): e0188104, 2017.
Article in English | MEDLINE | ID: mdl-29206226

ABSTRACT

The rapid and accurate identification of pathogen yeast species is crucial for clinical diagnosis due to the high level of mortality and morbidity induced, even after antifungal therapy. For this purpose, new rapid, high-throughput and reliable identification methods are required. In this work we described a combined approach based on two high-throughput techniques in order to improve the identification of pathogenic yeast strains. Next Generation Sequencing (NGS) of ITS and D1/D2 LSU marker regions together with FTIR spectroscopy were applied to identify 256 strains belonging to Candida genus isolated in nosocomial environments. Multivariate data analysis (MVA) was carried out on NGS and FT-IR data-sets, separately. Strains of Candida albicans, C. parapsilosis, C. glabrata and C. tropicalis, were identified with high-throughput NGS sequencing of ITS and LSU markers and then with FTIR. Inter- and intra-species variability was investigated by consensus principal component analysis (CPCA) which combines high-dimensional data of the two complementary analytical approaches in concatenated PCA blocks normalized to the same weight. The total percentage of correct identification reached around 97.4% for C. albicans and 74% for C. parapsilosis while the other two species showed lower identification rates. Results suggested that the identification success increases with the increasing number of strains actually used in the PLS analysis. The absence of reliable FT-IR libraries in the current scenario is the major limitation in FTIR-based identification of strains, although this metabolomics fingerprint represents a valid and affordable aid to rapid and high-throughput to clinical diagnosis. According to our data, FT-IR libraries should include some tens of certified strains per species, possibly over 50, deriving from diverse sources and collected over an extensive time period. This implies a multidisciplinary effort of specialists working in strain isolation and maintenance, molecular taxonomy, FT-IR technique and chemo-metrics, data management and data basing.


Subject(s)
Candida/genetics , High-Throughput Nucleotide Sequencing/methods , Spectroscopy, Fourier Transform Infrared/methods , Candida/classification , Genotype , Phenotype , Principal Component Analysis
17.
Neurochem Res ; 42(2): 493-500, 2017 Feb.
Article in English | MEDLINE | ID: mdl-28108849

ABSTRACT

The etiology and pathogenesis of Parkinson's disease (PD) are still unclear. However, multiple lines of evidence suggest a critical role of the toll like receptor 4 (TLR4) in inflammatory response and neuronal death. Neuroinflammation may be associated with the misfolding and aggregation of proteins accompanied by a change in their secondary structure. Recent findings also suggest that biochemical perturbations in cerebral lipid content could contribute to the pathogenesis of central nervous system (CNS) disorders, including PD. Thus, it is of great importance to determine the biochemical changes that occur in PD. In this respect, Fourier Transform Infrared (FTIR) spectroscopy represents a useful tool to detect molecular alterations in biological systems in response to stress stimuli. By relying upon FTIR approach, this study was designed to elucidate the potential role of TLR4 in biochemical changes induced by methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxin in a mouse model of PD. The analysis of the FTIR spectra was performed in different brain regions of both wild type (WT) and toll like receptor 4-deficient (TLR4-/-) mice. It revealed that each brain region exhibited a characteristic molecular fingerprint at baseline, with no significant differences between genotypes. Conversely, WT and TLR4-/- mice showed differential biochemical response to MPTP toxicity, principally related to lipid and protein composition. These differences appeared to be characteristic for each brain area. Furthermore, the present study showed that WT mice resulted more vulnerable than TLR4-/- animals to striatal dopamine (DA) depletion following MPTP treatment. These results support the hypothesis of a possible involvement of TLR4 in biochemical changes occurring in neurodegeneration.


Subject(s)
Cerebral Cortex/metabolism , Corpus Striatum/metabolism , MPTP Poisoning/metabolism , Parkinson Disease, Secondary/metabolism , Toll-Like Receptor 4/deficiency , Animals , Cerebral Cortex/chemistry , Cerebral Cortex/drug effects , Corpus Striatum/chemistry , Corpus Striatum/drug effects , MPTP Poisoning/chemically induced , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Parkinson Disease, Secondary/chemically induced
18.
Sci Rep ; 6: 26860, 2016 06 01.
Article in English | MEDLINE | ID: mdl-27246511

ABSTRACT

Two hundred seventy seven strains from eleven opportunistic species of the genus Candida, isolated from two Italian hospitals, were identified and analyzed for their ability to form biofilm in laboratory conditions. The majority of Candida albicans strains formed biofilm while among the NCAC species there were different level of biofilm forming ability, in accordance with the current literature. The relation between the variables considered, i.e. the departments and the hospitals or the species and their ability to form biofilm, was tested with the assessment of the probability associated to each combination. Species and biofilm forming ability appeared to be distributed almost randomly, although some combinations suggest a potential preference of some species or of biofilm forming strains for specific wards. On the contrary, the relation between biofilm formation and species isolation frequency was highly significant (R(2) around 0.98). Interestingly, the regression analyses carried out on the data of the two hospitals separately were rather different and the analysis on the data merged together gave a much lower correlation. These findings suggest that, harsh environments shape the composition of microbial species significantly and that each environment should be considered per se to avoid less significant statistical treatments.


Subject(s)
Biofilms/growth & development , Candida/physiology , Candidiasis/microbiology , Cross Infection/microbiology , Models, Biological , Candida/isolation & purification , Candida albicans/isolation & purification , Candida albicans/physiology , Hospital Departments , Hospitals, General , Humans , Opportunistic Infections/microbiology , Species Specificity , Yeasts/isolation & purification , Yeasts/physiology
19.
Langmuir ; 32(4): 1101-10, 2016 Feb 02.
Article in English | MEDLINE | ID: mdl-26752694

ABSTRACT

Zwitterionic sulfobetaine surfactants are used in pharmaceutical or biomedical applications for the solubilization and delivery of hydrophobic molecules in aqueous medium or in biological environments. In a screening on the biocidal activity of synthetic surfactants on microbial cells, remarkable results have emerged with sulfobetaine amphiphiles. The interaction between eight zwitterionic sulfobetaine amphiphiles and Saccharomyces cerevisiae model cells was therefore analyzed. S. cerevisiae yeast cells were chosen, as they are a widely used unicellular eukaryotic model organism in cell biology. Conductivity measurements were used to investigate the interaction between surfactant solution and cells. Viable counts measurements were performed, and the mortality data correlated with the conductivity profiles very well, in terms of the inflection points (IPs) observed in the curves and in terms of supramolecular properties of the aggregates. A Fourier transform infrared (FTIR)-based bioassay was then performed to determine the metabolomic stress-response of the cells subjected to the action of zwitterionic surfactants. The surfactants showed nodal concentration (IPs) with all the techniques in their activities, corresponding to the critical micellar concentrations of the amphiphiles. This is due to the pseudocationic behavior of sulfobetaine micelles, because of their charge distribution and charge densities. This behavior permits the interaction of the micellar aggregates with the cells, and the structure of the surfactant monomers has impact on the mortality and the metabolomic response data observed. On the other hand, the concentrations that are necessary to provoke a biocidal activity do not promote these amphiphiles as potential antimicrobial agents. In fact, they are much higher than the ones of cationic surfactants.


Subject(s)
Betaine/analogs & derivatives , Betaine/pharmacology , Disinfectants/pharmacology , Saccharomyces cerevisiae/drug effects , Surface-Active Agents/pharmacology , Betaine/chemistry , Conductometry , Disinfectants/chemistry , Electric Conductivity , Micelles , Saccharomyces cerevisiae/cytology , Spectroscopy, Fourier Transform Infrared , Surface-Active Agents/chemistry
20.
Mycopathologia ; 181(3-4): 297-303, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26588923

ABSTRACT

BACKGROUND: Trichoderma species are saprophytic filamentous fungi producing localized and invasive infections that are cause of morbidity and mortality, especially in immunocompromised patients, causing up to 53% mortality. Non-immunocompromised patients, undergoing continuous ambulatory peritoneal dialysis, are other targets of this fungus. Current molecular diagnostic tools, based on the barcode marker ITS, fail to discriminate these fungi at the species level, further increasing the difficulty associated with these infections and their generally poor prognosis. CASE REPORT: We report on the first case of endocarditis infection caused by Trichoderma longibrachiatum in a 30-year-old man. This patient underwent the implantation of an implantable cardioverter defibrillator in 2006, replaced in 2012. Two years later, the patient developed fever, treated successfully with amoxicillin followed by ciprofloxacin, but an echocardiogram showed large vegetation onto the ventricular lead. After CIED extraction, the patient had high-grade fever. The culturing of the catheter tip was positive only in samples deriving from sonication according to the 2014 ESCMID guidelines, whereas the simple washing failed to remove the biofilm cells from the plastic surface. Subsequent molecular (ITS sequencing) and microbiological (macromorphology) analyses showed that the vegetation was due to T. longibrachiatum. CONCLUSIONS: This report showed that T. longibrachiatum is an effective threat and that sonication is necessary for the culturing of vegetations from plastic surfaces. Limitations of the current barcode marker ITS, and the long procedures required by a multistep approach, call for the development of rapid monophasic tests.


Subject(s)
Antifungal Agents/therapeutic use , Biofilms/drug effects , Defibrillators, Implantable/adverse effects , Endocarditis/drug therapy , Heart/microbiology , Mycoses/drug therapy , Trichoderma/drug effects , Adult , Amphotericin B/therapeutic use , Base Sequence , DNA, Intergenic/genetics , Endocarditis/microbiology , Humans , Male , Mycoses/microbiology , Sequence Analysis, DNA , Trichoderma/classification , Trichoderma/genetics , Voriconazole/therapeutic use
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