Seasonal monitoring of microbiological air contamination from a museum - a case study

The aim of this study was to monitor microbial contamination in the work place of a museum, for estimating the influence of seasons, microclimatic parameters and tourists. The analysis was carried out in artefacts deposits, restoration laboratories and exhibition spaces. The media used to demonstrate the presence of biological agents, non-pathogenic and with pathogenic potential (opportunistic bacteria and filamentous fungi with haemolytic properties) were: simple agar, blood agar and Sabouraud with chloramphenicol. The isolated bacterial strains were identified by API tests and the fungal strains by examination of features with taxonomic value, aspects based on macroscopic observations of colony/cultures and microscopic assessment of mycelia. The counts of the microorganisms in the air were higher especially in the textiles deposits (the mesophilic microorganisms ranged from 200 to 1.4x104 CFU/m3). The filamentous fungi most frequently isolated species were: Aspergillus spp.; Penicillium spp., Cladosporium spp. The most frequently isolated bacteria swere: Staphylococcus (S. epidermidis, S. xylosus, S. capitis); Bacillus (B. cereus, Bacillus spp). The results of this study indicate a microbial air load containing both filamentous fungi and bacteria strains, including some opportunistic pathogens which can represent a health risk for the museums workers, especially in the seasons with higher exposure

The antifungal activity evaluation of new 2-((4-chlorophenoxy) methyl )-N- (arylcarbamothioyl) benzamides

Disciplina de Chimie farmaceutică, Facultatea de Farmacie , Universitatea de Medicină și Farmacie “Carol Davila”, București, România, Departamentul de Microbiologie, Facultatea de Biologie, Universitatea din București, București, RomâniaObiectivul studiului: Au fost proiectaţi, obţinuţi şi caracterizaţi noi derivați ai tioureei, în scopul evaluării activităţii antifungice. Materiale şi metode: Acidul 2-(4-clorofenoximetil)benzoic a fost refluxat cu clorură de tionil, obţinându-se clorura de 2-(4-clorofenoximetil)benzoil, care a reacționat cu tiocianatul de amoniu. Izotiocianatul de 2-(4-clorofenoximetil) benzoil rezultat, a fost tratat cu amine primare pentru a obţine noi derivaţi ai N-[2-(4-clorofenoximetil) benzoil]-tioureei N’-fenil substituite. Pentru evaluarea acţiunii antifungice s-au utilizat 6 tulpini de levuri izolate din surse industriale, 9 tulpini de levuri izolate din mediul clinic şi 11 tulpini de fungi filamentoşi izolaţi în urma procesului de control microbiologic al unor produse alimentare. Activitatea antifungică s-a testat calitativ, printr-o metodă difuzimetrică adaptată. Analiza cantitativă s-a realizat prin metoda microdiluţiilor seriale binare în mediu lichid. Studiul efectului sinergic al unor antifungice cu benzamidele nou sintetizate s-a realizat prin metoda E-Test. Rezultate: În urma screening-ului calitativ al activităţii antifungice a noilor bezamide testate pe levuri, s-a observat că eficienţa acestora a variat în funcţie de specia testată şi de compus. Dintre tulpinile industriale, cea mai sensibilă specie levurică s-a dovebit a fi Debariomyces hansenii. Sensibile au fost şi majoritatea tulpinilor clinice de Candida albicans. În metoda calitativă de determinare a activităţii noilor compuşi asupra tulpinilor de fungi filamentoşi, s-au observat modificări ale caracterelor de cultură, în sensul apariţiei unor colonii de dimensiuni mai reduse, ca urmare a afectării gradului de dezvoltare şi de maturare a hifelor miceliene. În determinarea cantitativă a activităţii antifungice prin stabilirea concentraţiei minime inhibitorii (CMI), în cazul levurilor, rezultate moderat vizibile s-au observat la unele specii de Candida albicans, compuşii cei mai activi fiind selectaţi pentru testarea efectului sinergic cu antifungice standard, prin metoda E-Test. În cazul testării pe tulpinile fungice de Aspergillus niger, pentru determinarea valorii CMI, s-a observat faptul că, în prezenţa unora dintre compuşi, la concentraţii mai mari, are loc persistenţa miceliului primar şi întârzierea fenomenului de maturare a miceliului secundar şi de sporulare, precum şi apariţia de corpi micelieni modificaţi. În cazul metodei E- Test, combinarea flucitozinei cu unii dintre compuși, a crescut gradul de sensibilitate al celulelor de Candida albicans la acţiunea antimicoticului. Concluzii: Au fost sintetizaţi și caracterizaţi prin spectrometrie IR, RMN și prin analiză elementală noi derivați ai benzamidei. Rezultatele testării acţiunii antifungice sugerează că acești compuși ar putea fi folosiţi în terapeutică. Studiile au fost finanţate prin contractul 13/23.12.2013 din competiţia „N. Testemiţanu”

Seasonal monitoring of microbiological air contamination from a museum - a case study

The aim of this study was to monitor microbial contamination in the work place of a museum, for estimating the influence of seasons, microclimatic parameters and tourists. The analysis was carried out in artefacts deposits, restoration laboratories and exhibition spaces. The media used to demonstrate the presence of biological agents, non-pathogenic and with pathogenic potential (opportunistic bacteria and filamentous fungi with haemolytic properties) were: simple agar, blood agar and Sabouraud with chloramphenicol. The isolated bacterial strains were identified by API tests and the fungal strains by examination of features with taxonomic value, aspects based on macroscopic observations of colony/cultures and microscopic assessment of mycelia. The counts of the microorganisms in the air were higher especially in the textiles deposits (the mesophilic microorganisms ranged from 200 to 1.4x104 CFU/m3). The filamentous fungi most frequently isolated species were: Aspergillus spp.; Penicillium spp., Cladosporium spp. The most frequently isolated bacteria swere: Staphylococcus (S. epidermidis, S. xylosus, S. capitis); Bacillus (B. cereus, Bacillus spp). The results of this study indicate a microbial air load containing both filamentous fungi and bacteria strains, including some opportunistic pathogens which can represent a health risk for the museums workers, especially in the seasons with higher exposure

Magnetite-Based Nanostructured Coatings Functionalized with <i>Nigella sativa</i> and Dicloxacillin for Improved Wound Dressings

In this study, we report the performance improvement of wound dressings by covering them with magnetite-based nanostructured coatings. The magnetite nanoparticles (Fe3O4 NPs) were functionalized with Nigella sativa (N. sativa) powder/essential oil and dicloxacillin and were synthesized as coatings by matrix assisted pulsed laser evaporation (MAPLE). The expected effects of this combination of materials are: (i) to reduce microbial contamination, and (ii) to promote rapid wound healing. The crystalline nature of core/shell Fe3O4 NPs and coatings was determined by X-ray diffraction (XRD). Differential Scanning Calorimetry (DSC) and Thermo Gravimetric Analysis (TGA) have been coupled to investigate the stability and thermal degradation of core/shell nanoparticle components. The coatings’ morphology was examined by scanning electron microscopy (SEM). The distribution of chemical elements and functional groups in the resulting coatings was evidenced by Fourier transform infrared (FTIR) spectrometry. In order to simulate the interaction between wound dressings and epithelial tissues and to evaluate the drug release in time, the samples were immersed in simulated body fluid (SBF) and investigated after different durations of time. The antimicrobial effect was evaluated in planktonic (free-floating) and attached (biofilms) bacteria models. The biocompatibility and regenerative properties of the nanostructured coatings were evaluated in vitro, at cellular, biochemical, and the molecular level. The obtained results show that magnetite-based nanostructured coatings functionalized with N. sativa and dicloxacillin are biocompatible and show an enhanced antimicrobial effect against Gram positive and Gram negative opportunistic bacteria

Preparation and Characterization of Chitosan/TiO2 Composite Membranes as Adsorbent Materials for Water Purification

As it is used in all aspects of human life, water has become more and more polluted. For the past few decades, researchers and scientists have focused on developing innovative composite adsorbent membranes for water purification. The purpose of this research was to synthesize a novel composite adsorbent membrane for the removal of toxic pollutants (namely heavy metals, antibiotics and microorganisms). The as-synthesized chitosan/TiO2 composite membranes were successfully prepared through a simple casting method. The TiO2 nanoparticle concentration from the composite membranes was kept low, at 1% and 5%, in order not to block the functional groups of chitosan, which are responsible for the adsorption of metal ions. Nevertheless, the concentration of TiO2 must be high enough to bestow good photocatalytic and antimicrobial activities. The synthesized composite membranes were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and swelling capacity. The antibacterial activity was determined against four strains, Escherichia coli, Citrobacter spp., Enterococcus faecalis and Staphylococcus aureus. For the Gram-negative strains, a reduction of more than 5 units log CFU/mL was obtained. The adsorption capacity for heavy metal ions was maximum for the chitosan/TiO2 1% composite membrane, the retention values being 297 mg/g for Pb2+ and 315 mg/g for Cd2+ ions. These values were higher for the chitosan/TiO2 1% than for chitosan/TiO2 5%, indicating that a high content of TiO2 can be one of the reasons for modest results reported previously in the literature. The photocatalytic degradation of a five-antibiotic mixture led to removal efficiencies of over 98% for tetracycline and meropenem, while for vancomycin and erythromycin the efficiencies were 86% and 88%, respectively. These values indicate that the chitosan/TiO2 composite membranes exhibit excellent photocatalytic activity under visible light irradiation. The obtained composite membranes can be used for complex water purification processes (removal of heavy metal ions, antibiotics and microorganisms)

Phenotypic and genotypic virulence features of staphylococcal strains isolated from difficult-to-treat skin and soft tissue infections.

Chronic infections represent an important burden on the healthcare system and have a significant impact on the patients' quality of life. While Staphylococcus spp. are commensal bacteria, they can become pathogenic, leading to various types of infections. In this study we aimed to characterize the virulence profiles of staphylococcal strains involved in difficult-to-treat skin and soft tissue infections, from both phenotypic and genotypic points of view. Phenotypic ability of the strains to secrete soluble virulence factors was assessed by a culturing dependent assay and their capacity to develop biofilms on inert substrate was screened by an adapted crystal violet microtiter method. We also tested the presence of several virulence genes by PCR. Most of the studied strains were isolated from purulent secretions of acne lesions and frequently secreted two or three soluble virulence factors. Most frequently secreted soluble virulence factors were caseinase (89%), lipase (71%) and lecithinase (67%). Almost half of the strains produced a well-represented biofilm. The molecular characterization showed the presence of the genes cna, hlg, clfA, and clfB. Staphylococcal strains that produce difficult-to-treat skin and soft tissue infections seem to be characterized by an enhanced ability to produce different soluble virulence factors and to develop biofilms in vitro. Further studies need to be developed in other Staphylococcus spp. infections in order to confirm this hypothesis

DataSheet1_Alternative mitigating solutions based on inorganic nanoparticles for the preservation of cultural heritage.PDF

Introduction: Biodeterioration is a big challenge for the preservation of cultural heritage objects and for the community’s safety, fostering the search for novel methods effective in removing microbial biofilms and subsequent biodeterioration. In this context, nanoparticles (NPs) are considered an interesting alternative, based on their unique physico-chemical and biological properties.Methods: The present study aimed to evaluate the antimicrobial efficiency of Ag, Au, Cu, and ZnO NPs against a significant number of filamentous fungi and bacterial strains isolated from wooden and stone cultural heritage objects from different Romanian regions, as well as from museum collections, with the final goal to establish their potential to develop novel preservation strategies, which have high efficiency and low ecotoxicity.Results: Six types of nanoparticles (NPs) based on Ag, Au, Cu, and ZnO were synthesized and characterized for their physico-chemical properties, ecotoxicity, and efficacy against 75 filamentous fungi and 17 bacterial strains isolated from wooden and stone cultural heritage objects (15th–19th century). The results showed that all synthetized NPs are homogeneous, demonstrating a good stabilizing coating, and have spherical or triangular shapes, with sizes between 9 and 25 nm. The highest antifungal efficiency has been recorded for Ag NPs, followed by Cu NPs and ZnO NPs, with the most susceptible strains being Aspergillus montevidensis, Penicillium commune, Penicillium corylophilum, Bacillus megaterium, and B. cereus. The Cu NPs and ZnO NPs decreased the capacity of microbial strains to adhere to the inert substratum. The influence of the tested NPs against enzyme/organic acid production varied depending on the NP types and by species.Conclusion: The obtained results are promising for the development of efficient and economical alternative solutions for heritage preservation, showing high antimicrobial activity against the prevalent fungal and bacterial strains involved in the biodeterioration of Romanian heritage objects.</p