Andrea Cellini

Sapienza University of Rome, Roma, Latium, Italy

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Publications (13)21.14 Total impact

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    ABSTRACT: Coagulase-negative staphylococci (CoNS) belong to saprophytic microbiota on the skin and mucous membranes of warm-blooded animals and humans, but are also isolated from foodstuffs such as meat, cheese, and milk. In other circumstances, some CoNS can act as pathogens. Thus the presence of CoNS may not be an immediate danger to public health, but can become a risk factor. In particular antibiotic-resistant genes could be transferred to other potentially pathogenic microorganisms. Furthermore, CoNS are known to be strong biofilm producers and this is also a risk factor for public health.The aim of the present work was to determine the genotypic and phenotypic profiles of 106 CoNS belonging to four different species isolated from five different Italian cheeses for the presence of some adhesion and virulence features. In order to verify a possible correlation between the formation of biofilm and staphylococcal virulence factors, we checked the presence of adhesin genes by PCR and we investigated the ability of these strains to make biofilm at different temperatures. Furthermore, in some conditions, we analyzed surface proteins and autolytic pattern of selected strains. In conclusion, we checked the presence of norA and mecA genes responsible for fluoroquinolones and methicillin resistance, respectively. We found resistant genes in a proportion of the food isolates in amounts of 9.4% (mecA) and 5.7% (norA). These data support the importance to continuously examine the microbiota not only for the creation of a database but also to safeguard public health. © The Author(s) 2015.
    No preview · Article · Aug 2015 · International journal of immunopathology and pharmacology
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    ABSTRACT: No sooner are contact lenses (CLs) inserted into the eyes than lipids, proteins, and glycoproteins rapidly accumulate on their surface, thus favoring the adhesion of commensal bacteria and biofilm formation. Infections may be caused by the proliferation of indigenous flora or other opportunistic pathogens. Our purpose was to evaluate the activity and the capacity of different CL solutions to interfere with the mechanisms of biofilm formation and stability and use of a system to study dynamically biofilm development. We evaluated the antibiofilm activity of three different multipurpose solutions (MPSs): Regard, Biotrue, and OPTI-FREE PureMoist on four bacterial species (Serratia marcescens, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Staphylococcus aureus). Static biofilm assay was first performed to analyze the effect of MPSs. Dynamic assays were performed with the BioFlux system to analyze the effect of the OxyChlorite solution Regard on the biofilm formation. Our studies show that MPSs are able to completely inhibit biofilm formation of Staphylococcus species and of S. marcescens after only 4 hr of incubation. Moreover, a reduction of biofilm formation by Pseudomonas was noted. Best results on P. aeruginosa were obtained with Regard. Regard was also used for dynamic assay, revealing its ability to disaggregate the mature biofilm. Regard completely inhibited biofilm formation by S. epidermidis and slowed down biofilm development by P. aeruginosa. Our findings indicate that the CL solutions tested were all able to reduce biofilm formation. Furthermore, the BioFlux system was proven to be useful for the evaluation of the effectiveness of CL solutions against microbial biofilm formation.
    No preview · Article · Mar 2015 · Eye & contact lens
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    ABSTRACT: Staphylococcus epidermidis is recognized as cause of biofilm-associated infections and interest in the development of new approaches for S. epidermidis biofilm treatment has increased. In a previous paper we reported that the supernatant of Antarctic bacterium Pseudoalteromonas haloplanktis TAC125 presents an anti-biofilm activity against S. epidermidis and preliminary physico-chemical characterization of the supernatant suggested that this activity is due to a polysaccharide. In this work we further investigated the chemical nature of the anti-biofilm P. haloplanktis TAC125 molecule. The production of the molecule was evaluated in different conditions, and reported data demonstrated that it is produced in all P. haloplanktis TAC125 biofilm growth stages, also in minimal medium and at different temperatures. By using a surface coating assay, the surfactant nature of the anti-biofilm compound was excluded. Moreover, a purification procedure was set up and the analysis of an enriched fraction demonstrated that the anti-biofilm activity is not due to a polysaccharide molecule but that it is due to small hydrophobic molecules that likely work as signal. The enriched fraction was also used to evaluate the effect on S. epidermidis biofilm formation in dynamic condition by BioFlux system. © The Author(s) 2015.
    Full-text · Article · Mar 2015 · International journal of immunopathology and pharmacology
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    M Artini · R Papa · A Cellini · M Tilotta · G Barbato · A Koverech · L Selan
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    ABSTRACT: Betamethasone is an anti-inflammatory steroid drug used in cases of anaphylactic and allergic reactions, of Alzheimer and Addison diseases and in soft tissue injuries. It modulates gene expression for anti-inflammatory activity suppressing the immune system response. This latter effect might decrease the effectiveness of immune system response against microbial infections. Corticosteroids, in fact, mask some symptoms of infection and during their use superimposed infections may occur. Thus, the use of glucocorticoids in patients with sepsis remains extremely controversial. In this study we analyzed the in vitro effect of a commercial formulation of betamethasone (Bentelan) on several Gram positive and Gram negative bacteria of clinical relevance. It was found to be an inhibitor of the growth of most of the strains examined. Also the effect of betamethasone in combination with some classes of antibiotics was evaluated. Antibiotic-steroid combination therapy is, in such cases, superior to antibiotic-alone treatment to impair bacterial growths. Such effect was essentially not at all observable on Staphylococcus aureus or Coagulase Negative Staphylococci (CoNS).
    Full-text · Article · Oct 2014 · International journal of immunopathology and pharmacology

  • No preview · Presentation · Oct 2013
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    ABSTRACT: Staphylococcus aureus is a flexible microbial pathogen frequently isolated from community-acquired and nosocomial infections. S. aureus expresses a wide array of secreted and cell surface-associated virulence factors, including proteins that promote adhesion to damaged tissue and to the surface of host cells, and that bind proteins in blood to help evade immune responses. Furthermore, surface proteins have a fundamental role in virulence related properties of S. aureus, including biofilm formation. The present study evaluates the anti-infective capabilities of a secreted protein of Serratia marcescens (serratiopeptidase, SPEP), in impairing some staphylococcal virulence-related properties, such as attachment to inert surfaces and adhesion/invasion on eukaryotic cells. SPEP seems to exert its action by modulating specific proteins. It is not assessed if this action is due to the proteolytic activity of SPEP or to a specific mechanism which triggers an out/inside signal. Proteomic studies performed on surface proteins extracted from SPEP treated S. aureus cultures revealed that a number of proteins are affected by the treatment. Among these we found the adhesin/autolysin Atl, SdrD, Sbi, EF-Tu and EF-G. EF-Tu and EF-G are known to perform a variety of function, depending on their cytoplasmic or surface localization. All these factors can facilitate bacterial colonization, persistence and invasion of host tissues. Our results suggest that SPEP could be developed as a potential ''anti-infective agent'' capable to hinder the entry of S. aureus into human tissues, and also impairs the ability of this pathogen to adhere to prostheses, catheters and medical devices.
    No preview · Article · Jun 2013 · Microbial Pathogenesis
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    M Artini · G L Scoarughi · A Cellini · R Papa · G Barbato · L Selan
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    ABSTRACT: Staphylococcus aureus and Staphylococcus epidermidis are the major cause of infections associated with implanted medical devices. Colonization on abiotic and biotic surfaces is often sustained by biofilm forming strains. Human natural defenses can interfere with this virulence factor. We investigated the effect of human apo-transferrin (apo-Tf, the iron-free form of transferrin, Tf) and holo-transferrin (holo-Tf, the iron-saturated form) on biofilm formation by CA-MRSA S. aureus USA300 type (ST8-IV) and S. epidermidis (a clinical isolate and ATCC 35984 strain). Furthermore S. aureus adhesion and invasion assays were performed in a eukaryotic cell line. A strong reduction in biofilm formation with both Tfs was obtained albeit at very different concentrations. In particular, the reduction in biofilm formation was higher with apo-Tf rather than obtained with holo-Tf. Furthermore, while S. aureus adhesion to eukaryotic cells was not appreciably affected, their invasion was highly inhibited in the presence of holo-Tf, and partially inhibited by the apo form. Our results suggest that Tfs could be used as antibacterial adjuvant therapy in infection sustained by staphylococci to strongly reduce their virulence related to adhesion and cellular invasion.
    Full-text · Article · Jan 2012 · Biology of Metals
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    ABSTRACT: Use of herbal plant remedies to treat infectious diseases is a common practice in many countries in traditional and alternative medicine. However to date there are only few antimicrobial agents derived from botanics. Based on microbiological screening tests of crude plant extracts we identified four compounds derived from Krameria, Aesculus hippocastanum and Chelidonium majus that showed a potentially interesting antimicrobial activity. In this work we present an in depth characterization of the inhibition activity of these pure compounds on the formation of biofilm of Staphylococcus aureus as well as of Staphylococcus epidermidis strains. We show that two of these compounds possess interesting potential to become active principles of new drugs.
    Full-text · Article · Dec 2011 · Bioorganic & medicinal chemistry
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    ABSTRACT: Staphylococcus aureus is a flexible microbial pathogen frequently isolated from community-acquired and nosocomial infections. The use of indwelling medical devices is associated with a significant risk of infection by this bacterium which possesses a variety of virulence factors, including many toxins, and the ability to invade eukaryotic cells or to form biofilm on biotic and abiotic surfaces. The present study evaluates the anti-infective properties of serratiopeptidase, a secreted protein of Serratia marcescens, in impairing virulence-related staphylococcal properties, such as attachment to inert surfaces and adhesion/invasion on eukaryotic cells. SPEP seems to exert its action by modulating specific proteins. Proteomic studies performed on surface proteins extracted from SPEP-treated S. aureus cultures revealed that a number of proteins are affected by the treatment. Among these we found the adhesin/autolysin Atl, FnBP-A, SecA1, Sbi, EF-Tu, EF-G, and alpha-enolase. EF-Tu, EF-G and alpha-enolase are known to perform a variety of functions, depending on their cytoplasmic or surface localization. All these factors can facilitate bacterial colonization, persistence and invasion of host tissues. Our results suggest that SPEP could be developed as a potential anti-infective agent capable to hinder the entry of S. aureus into human tissues, and also impair the ability of this pathogen to form biofilm on prostheses, catheters and medical devices.
    Full-text · Article · Jul 2011 · International journal of immunopathology and pharmacology
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    ABSTRACT: The main problem associated with artificial vascular devices is the risk of bacterial infections, mostly sustained by coagulase negative Staphylococci or Staphylococcus aureus. Many efforts have been made to identify materials refractory to bacterial adhesion. The aim of our study is to verify the antimicrobial properties of two kinds of vascular prosthesis to prevent early onset infections and the efficacy of the concomitant action of a systemic antibiotic treatment. Adult male Wistar rats were used. We subcutaneously implanted in four groups a silver-coated prosthesis fragment, and a rifampicin-soaked prosthesis fragment in the remaining four groups. We inoculated in the site of implant a high bacterial burden of S. aureus in four groups and a low burden in the remaining groups. Systemic levofloxacin was administered for seven days in four groups representing the two kinds of prosthesis; after 21 days the rats were sacrificed, prosthesis fragments were sonicated and the corresponding supernatants were plated for bacterial counts. The rifampicin-soaked prostheses explanted from rats treated with levofloxacin were sterile, regardless of the bacterial inoculum. In other groups some prostheses were colonized. In the experimental rat model used, the action of local and systemic antibiotic treatment was able to reduce colonisation of artificial prostheses.
    No preview · Article · Jan 2010 · International journal of immunopathology and pharmacology
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    ABSTRACT: Background: Benzofurans of natural origin (alkaloids, pterocarpans, flavonoids etc.) possess a wide range of biological activities including antioxidant, antimicrobial and anti-inflammatory activities. We analyzed the antimicrobial effect of a synthetic derivative of dihydroxybenzofuran (DHBF), originally isolated from Krameria lappacea (Dombey) Burdet. This plant is well known in medicine for its bronchodilator, antiviral, antioxidant and photoprotective properties due to the high production of lignans and neolignans. In the present study the effect of DHBF was analyzed for its antibacterial activity against S. aureus and S. epidermidis. Methods: S. aureus 6538P and S. epidermidis RP62A strains were used. Determination of MIC and MBC for DHBF was carried out. Its influence on biofilm formation was assessed using crystal violet. The effect of DHBF on surface proteins and autolysins was evaluated by SDS-PAGE and zymogram. Surface proteins were extracted from bacteria grown in absence and in presence of sub-inhibiting concentration of DHBF. In order to study the modulation of surface adhesins/autolysins, zymograms were also performed. Results: DHBF shows a strong bactericidal activity on the planktonic form of the two tested bacterial strains. A marked inhibition of biofilm formation was also observed. A significant reduction of preformed biofilm was observed in both strains at concentrations twice than MIC/MBC values. SDS-PAGE analysis revealed a modification of surface protein pattern in treated bacteria in comparison with that of untreated bacteria. Analysis of zymogram pattern under the same conditions is ongoing. Conclusions: Our data show that DHBF treatment is effective to impair adhesion by Staphylococcus spp on abiotic surfaces. DHBF strongly reduces also the biomass of preformed biofilm, suggesting a possible application in biofilm infections.
    No preview · Conference Paper · Oct 2008
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    ABSTRACT: Listeria monocytogenes is a notably invasive bacterium associated with life-threatening food-borne disease in humans. Several surface proteins have been shown to be essential in the adhesion of L. monocytogenes, and in the subsequent invasion of phagocytes. Because the control of the invasion of host cells by Listeria could potentially hinder its spread in the infected host, we have examined the effects of a protease treatment on the ability of L. monocytogenes to form biofilms and to invade tissues. We have chosen serratiopeptidase (SPEP), an extracellular metalloprotease produced by Serratia marcescens that is already widely used as an anti-inflammatory agent, and has been shown to modulate adhesin expression and to induce antibiotic sensitivity in other bacteria. Treatment of L. monocytogenes with sublethal concentrations of SPEP reduced their ability to form biofilms and to invade host cells. Zymograms of the treated cells revealed that Ami4b autolysin, internalinB, and ActA were sharply reduced. These cell-surface proteins are known to function as ligands in the interaction between these bacteria and their host cells, and our data suggest that treatment with this natural enzyme may provide a useful tool in the prevention of the initial adhesion of L. monocytogenes to the human gut.
    Full-text · Article · Aug 2008 · Microbial Pathogenesis
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    ABSTRACT: Six Archaea belonging to the phylum Euryarchaeota were previously analyzed with respect to stringent control. Only one of the strains studied was shown to possess Bacteria-like stringent control over stable RNA accumulation; ppGpp and pppGpp production was totally lacking in all Archaea analyzed. To broaden our knowledge of stringent control in the Archaea, we examined here the accumulation of stable RNA and the production of ppGpp and pppGpp under amino acid starvation in three species of the genus Sulfolobus belonging to the Crenarchaeota, an archaeal phylum distant from the Euryarchaeota. In these species the accumulation of sRNA was arrested when aminoacylation of tRNA was inhibited by pseudomonic acid. Furthermore, stringent control of stable RNA accumulation was relaxed by some protein synthesis inhibitors that do not interfere with aminoacylation of tRNA, a feature typical of bacterial stringent control. Neither ppGpp nor pppGpp could be detected during growth or under amino acid starvation, and the intracellular GTP levels did not decrease in the course of the stringent response. These results show that: (1) stringency is widespread in wild-type thermoacidophilic archaea; (2) in the crenarchaeal species analyzed here SC depends on the deaminoacylation of tRNA; (3) in the strains analyzed ppGpp is not produced during normal growth nor during the stringent reaction; it is therefore not an effector either of SC over sRNA synthesis or of growth control. (p)ppGpp appears to be completely absent from the Archaea and thus constitutes an additional feature that distinguishes the Bacteria from the Archaea.
    No preview · Article · Apr 2004 · Research in Microbiology