Resistance to colistin : what is the fate for this antibiotic in pig production?

Colistin, a cationic polypeptide antibiotic, has reappeared in human medicine as a last-line treatment option for multidrug-resistant Gram-negative bacteria (MDR-GNB). Colistin is widely used in veterinary medicine for the treatment of gastrointestinal infections caused by Enterobacteriaceae. GNB resistant to colistin owing to chromosomal mutations have already been reported both in human and veterinary medicine, however several recent studies have just identified a plasmid-mediated mcr-1 gene encoding for colistin resistance in Escherichia coli colistin resistance. The discovery of a non-chromosomal mechanism of colistin resistance in E. coli has led to strong reactions in the scientific community and to concern among physicians and veterinarians. Colistin use in food animals and particularly in pig production has been singled out as responsible for the emergence of colistin resistance. The present review will focus mainly on the possible link between colistin use in pigs and the spread of colistin resistance in Enterobacteriaceae. First we demonstrate a possible link between Enterobacteriaceae resistance emergence and oral colistin pharmacokinetics/pharmacodynamics and its administration modalities in pigs. We then discuss the potential impact of colistin use in pigs on public health with respect to resistance. We believe that colistin use in pig production should be re-evaluated and its dosing and usage optimised. Moreover, the search for competitive alternatives to using colistin with swine is of paramount importance to preserve the effectiveness of this antibiotic for the treatment of MDR-GNB infections in human medicine.

Chitosan gel film bandages: correlating structure, composition, and antimicrobial properties

Chitosan gel films were successfully obtained by evaporation cast from chitosan solutions in aqueous acidic solutions of organic acids (lactic and acetic acid) as gel film bandages, with a range of additives that directly influence film morphology and porosity. We show that the structure and composition of a wide range of 128 thin gel films, is correlated to the antimicrobial properties, their biocompatibility and resistance to biodegradation. Infrared spectroscopy and solid-state 13C nuclear magnetic resonance spectroscopy was used to correlate film molecular structure and composition to good antimicrobial properties against 10 of the most prevalent Gram positive and Gram negative bacteria. Chitosan gel films reduce the number of colonies after 24 h of incubation by factors of ∼105–107 CFU/mL, compared with controls. For each of these films, the structure and preparation condition has a direct relationship to antimicrobial activity and effectiveness. These gel film bandages also show excellent stability against biodegradation with lysozyme under physiological conditions (5% weight loss over a period of 1 month, 2% in the first week), allowing use during the entire healing process. These chitosan thin films and subsequent derivatives hold potential as low-cost, dissolvable bandages, or second skin, with antimicrobial properties that prohibit the most relevant intrahospital bacteria that infest burn injuries.

A Scalable Synthesis of the Difluoromethyl-allo-threonyl Hydroxamate-Based LpxC Inhibitor LPC-058.

The difluoromethyl-allo-threonyl hydroxamate-based compound LPC-058 is a potent inhibitor of UDP-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine deacetylase (LpxC) in Gram-negative bacteria. A scalable synthesis of this compound is described. The key step in the synthetic sequence is a transition metal/base-catalyzed aldol reaction of methyl isocyanoacetate and difluoroacetone, giving rise to 4-(methoxycarbonyl)-5,5-disubstituted 2-oxazoline. A simple NMR-based determination of enantiomeric purity is also described.

A systematic analysis of the role of GGDEF-EAL domain proteins in virulence and motility in Xanthomonas oryzae pv. oryzicola

The second messenger c-di-GMP is implicated in regulation of various aspects of the lifestyles and virulence of Gram-negative bacteria. Cyclic di-GMP is formed by diguanylate cyclases with a GGDEF domain and degraded by phosphodiesterases with either an EAL or HD-GYP domain. Proteins with tandem GGDEF-EAL domains occur in many bacteria, where they may be involved in c-di-GMP turnover or act as enzymatically-inactive c-di-GMP effectors. Here, we report a systematic study of the regulatory action of the eleven GGDEF-EAL proteins in Xanthomonas oryzae pv. oryzicola, an important rice pathogen causing bacterial leaf streak. Mutational analysis revealed that XOC_2335 and XOC_2393 positively regulate bacterial swimming motility, while XOC_2102, XOC_2393 and XOC_4190 negatively control sliding motility. The ΔXOC_2335/XOC_2393 mutant that had a higher intracellular c-di-GMP level than the wild type and the ΔXOC_4190 mutant exhibited reduced virulence to rice after pressure inoculation. In vitro purified XOC_4190 and XOC_2102 have little or no diguanylate cyclase or phosphodiesterase activity, which is consistent with unaltered c-di-GMP concentration in ΔXOC_4190. Nevertheless, both proteins can bind to c-di-GMP with high affinity, indicating a potential role as c-di-GMP effectors. Overall our findings advance understanding of c-di-GMP signaling and its links to virulence in an important rice pathogen.

Resistance to colistin : what is the fate for this antibiotic in pig production?

Colistin, a cationic polypeptide antibiotic, has reappeared in human medicine as a last-line treatment option for multidrug-resistant Gram-negative bacteria (MDR-GNB). Colistin is widely used in veterinary medicine for the treatment of gastrointestinal infections caused by Enterobacteriaceae. GNB resistant to colistin owing to chromosomal mutations have already been reported both in human and veterinary medicine, however several recent studies have just identified a plasmid-mediated mcr-1 gene encoding for colistin resistance in Escherichia coli colistin resistance. The discovery of a non-chromosomal mechanism of colistin resistance in E. coli has led to strong reactions in the scientific community and to concern among physicians and veterinarians. Colistin use in food animals and particularly in pig production has been singled out as responsible for the emergence of colistin resistance. The present review will focus mainly on the possible link between colistin use in pigs and the spread of colistin resistance in Enterobacteriaceae. First we demonstrate a possible link between Enterobacteriaceae resistance emergence and oral colistin pharmacokinetics/pharmacodynamics and its administration modalities in pigs. We then discuss the potential impact of colistin use in pigs on public health with respect to resistance. We believe that colistin use in pig production should be re-evaluated and its dosing and usage optimised. Moreover, the search for competitive alternatives to using colistin with swine is of paramount importance to preserve the effectiveness of this antibiotic for the treatment of MDR-GNB infections in human medicine.

Identification and bioactivity evaluation of two novel temporins from the skin secretion of the European edible frog, Pelophylax kl. Esculentus

The amphibian temporins, amongst the smallest antimicrobial peptides (AMPs), are α-helical, amphipathic, hydrophobic and cationic and are active mainly against Gram-positive bacteria but inactive or weakly active against Gram-negative bacteria. Here, we report two novel members of the temporin family, named temporin-1Ee (FLPVIAGVLSKLFamide) and temporin-1Re (FLPGLLAGLLamide), whose biosynthetic precursor structures were deduced from clones obtained from skin secretion-derived cDNA libraries of the European edible frog, Pelophylax kl. esculentus, by ‘shotgun’ cloning. Deduction of the molecular masses of each mature processed peptide from respective cloned cDNAs was used to locate respective molecules in reverse-phase HPLC fractions of secretion. Temporin-1Ee (MIC = 10 μM) and temporin-1Re (MIC = 60 μM) were both found to be active against Gram-positive Staphylococcus aureus, but retaining a weak haemolytic activity. To our knowledge, Single-site substitutions can dramatically change the spectrum of activity of a given temporin. Compared with temporine-1Ec, just one chemically-conservative substitution (Val8 instead of Leu8), temporin-1Ee bearing a net charge of +2 displays broad-spectrum activity with particularly high potency on the clinically relevant Gram-negative strains, Escherichia coli (MIC = 40 μM). These factors bode well for translating temporins to be potential drug candidates for the design of new and valuable anti-infective agents.

Structure and lipid interactions of membrane-associated glycosyltransferases : Cationic patches and anionic lipids regulate biomembrane binding of both GT-A and GT-B enzymes

This thesis concerns work on structure and membrane interactions of enzymes involved in lipid synthesis, biomembrane and cell wall regulation and cell defense processes. These proteins, known as glycosyltransferases (GTs), are involved in the transfer of sugar moieties from nucleotide sugars to lipids or chitin polymers. Glycosyltransferases from three types of organisms have been investigated; one is responsible for vital lipid synthesis in Arabidopsis thaliana (atDGD2) and adjusts the lipid content in biomembranes if the plant experiences stressful growth conditions. This enzyme shares many structural features with another GT found in gram-negative bacteria (WaaG). WaaG is however continuously active and involved in synthesis of the protective lipopolysaccharide layer in the cell walls of Escherichia coli. The third type of enzymes investigated here are chitin synthases (ChS) coupled to filamentous growth in the oomycete Saprolegnia monoica. I have investigated two ChS-derived MIT domains that may be involved in membrane interactions within the endosomal pathway. From analysis of the three-dimensional structure and the amino-acid sequence, some important regions of these very large proteins were selected for in vitro studies. By the use of an array of biophysical methods (e.g. Nuclear Magnetic Resonance, Fluorescence and Circular Dichroism spectroscopy) and directed sequence analyses it was possible to shed light on some important details regarding the structure and membrane-interacting properties of the GTs. The importance of basic amino-acid residues and hydrophobic anchoring segments, both generally and for the abovementioned proteins specifically, is discussed. Also, the topology and amino-acid sequence of GT-B enzymes of the GT4 family are analyzed with emphasis on their biomembrane association modes. The results presented herein regarding the structural and lipid-interacting properties of GTs aid in the general understanding of glycosyltransferase activity. Since GTs are involved in a high number of biochemical processes in vivo it is of outmost importance to understand the underlying processes responsible for their activity, structure and interaction events. The results are likely to be useful for many applications and future experimental design within life sciences and biomedicine.

Simvastatin improves the healing of infected skin wounds of rats

This study explores the potential of the simvastatin to ameliorate inflammation and infection in open infected skin wounds of rats. Methods: Fourteen Wistar rats weighing 285±12g were used. The study was done in a group whose open infected skin wounds were treated with topical application of sinvastatina microemulsion (SIM, n=7) and a second group with wounds treated with saline 0.9 % (SAL, n=7). A bacteriological exam of the wounds fluid for gram positive and gram negative bacteria, the tecidual expression of TNFá and IL-1â by imunohistochemical technique, and histological analysis by HE stain were performed. Results: The expression of TNFa could be clearly demonstrated in lower degree in skin wounds treated with simvastatin (668.6 ± 74.7 ìm2) than in saline (2120.0 ± 327.1 ìm2). In comparison, wound tissue from SIM group displayed leukocyte infiltration significantly lower than that observed in SAL group (p<0.05). Culture results of the samples taken from wound fluid on fourth post treatment day revealed wound infection in only one rat of group simvastatin (SIM), where Proteus mirabilis, Escherchia coli and Enterobacter sp were isolated. In the rats whose wounds were treated with saline (SAL), polymicrobial infection with more than 100,000 CFU/g was detected in all the wounds. Conclusion: In addition to its antiinflammatory properties, the protective effects of simvastatin in infected open skin wounds is able to reduce infection and probably has antibacterial action. The potential to treat these wounds with statins to ameliorate inflammation and infection is promising

Sources of antibiotic resistance in the environment

The discovery of antibiotics was a major breakthrough in medicine. However, short after their introduction in clinical practice resistant bacteria were detected. Nowadays, antibiotic resistance constitutes a serious public health problem. In hospital settings, with high resistance levels, reducing drastically the therapeutic options. Carbapenems are last-resort antibiotics used in Portugal, only in hospitals, to treat serious infections. Bacterial resistance towards this class of antibiotics has increased during last years. In Gram-negative bacteria the production of carbapenemases is a common resistance mechanism. OXA-48 is a carbapenemase of Ambler class D and represents a major concern for human health. It is frequently detected in clinical isolates of Enterobacteriaceae. There are few studies suggesting that genes encoding for OXA-48 variants originated from genes present in the chromosome of members of genus Shewanella, and have disseminated to Enterobacteriaceae members, associated with mobile genetic elements. The aim of this study was to characterize strains from different sources of Shewanella to confirm its role as OXA-48 progenitor. For this, the phylogenetic affiliation of 33 strains of Shewanella was performed by 16SrDNA and gyrB sequencing. The most common species were S. hafniensis and S. xiamenensis, but also S. aestuarii, S. baltica, S. indica, S. haliotis, S. putrefaciens, S. algidipiscicola, S. irciniae, S. algae and S. fodinae were identified. blaOXA-48-like genes were detected in 21 isolates: S. hafniensis (8/8), S. xiamenensis (5/5), S. baltica (4/4), S. algae (1/1), S. fodinae (1/1), S. putrefaciens (1/2) and S. algidipiscicola (1/2). Sequence analysis revealed that genes encoded enzymes identical to OXA-48, OXA-181 and OXA-204 but also new variants differing from OXA-48 from 2 to 81 aminoacids. Genetic context analysis revealed the C15 gene upstream and lysR gene downstream, identical to what has been identified so far flanking blaOXA-48-like genes in Shewanella spp. The assessment of antibiotic susceptibility was performed for all isolates using the disk diffusion method. In general, it was observed a great sensitivity for all antibiotics except to amoxicillin and aztreonam. Multidrug resistance was detected in only 1 isolate. Other resistance genes and the presence of integrons were not identified. Plasmids were detected in 30.3% isolates (10/ 33). These results reinforce the role of Shewanella spp. as origin of blaOXA-48-like genes.

Genome Wide Association Studies of Phagocytosis and the Cellular Immune Response in Drosophila melanogaster.

Phagocytosis of bacteria by specialized blood cells, known as hemocytes, is a vital component of Drosophila cellular immunity. To identify novel genes that mediate the cellular response to bacteria, we conducted three separate genetic screens using the Drosophila Genetic Reference Panel (DGRP). Adult DGRP lines were tested for the ability of their hemocytes to phagocytose the Gram-positive bacteria Staphylococcus aureus or the Gram-negative bacteria Escherichia coli. The DGRP lines were also screened for the ability of their hemocytes to clear S. aureus infection through the process of phagosome maturation. Genome-wide association analyses were performed to identify potentially relevant single nucleotide polymorphisms (SNPs) associated with the cellular immune phenotypes. The S. aureus phagosome maturation screen identified SNPs near or in 528 candidate genes, many of which have no known role in immunity. Three genes, dpr10, fred, and CG42673, were identified whose loss-of-function in blood cells significantly impaired the innate immune response to S. aureus. The DGRP S. aureus screens identified variants in the gene, Ataxin 2 Binding Protein-1 (A2bp1) as important for the cellular immune response to S. aureus. A2bp1 belongs to the highly conserved Fox-1 family of RNA-binding proteins. Genetic studies revealed that A2bp1 transcript levels must be tightly controlled for hemocytes to successfully phagocytose S. aureus. The transcriptome of infected and uninfected hemocytes from wild type and A2bp1 mutant flies was analyzed and it was found that A2bp1 negatively regulates the expression of the Immunoglobulin-superfamily member Down syndrome adhesion molecule 4 (Dscam4). Silencing of A2bp1 and Dscam4 in hemocytes rescues the fly’s immune response to S. aureus indicating that Dscam4 negatively regulates S. aureus phagocytosis. Overall, we present an examination of the cellular immune response to bacteria with the aim of identifying and characterizing roles for novel mediators of innate immunity in Drosophila. By screening panel of lines in which all genetic variants are known, we successfully identified a large set of candidate genes that could provide a basis for future studies of Drosophila cellular immunity. Finally, we describe a novel, immune-specific role for the highly conserved Fox-1 family member, A2bp1.

Novas estratégias para entender o sistema de influxo de antibióticos e a resistência antimicrobiana a nível molecular

As fluoroquinolonas são antibióticos que têm um largo espectro de ação contra bactérias, especialmente Gram-negativas. O seu mecanismo de ação assenta na inibição de enzimas responsáveis pela replicação do DNA. Porém, devido ao seu uso indevido, o surgimento de resistência bacteriana a estes antibióticos tem-se tornado um grave problema de saúde pública. Uma vez que os seus alvos de ação se situam no meio intracelular, a redução da permeabilidade da membrana externa de bactérias Gram-negativas constitui um dos mecanismos de resistência mais conhecidos. Esta redução é associada à baixa expressão ou mutações em porinas necessárias para permitir o seu transporte, mais concretamente, da OmpF. Estudos prévios demonstraram que a coordenação de fluoroquinolonas com iões metálicos divalentes e 1,10-fenantrolina (genericamente designados metaloantibióticos) são potenciais candidatos como alternativa às fluoroquinolonas convencionais. Estes metaloantibióticos exibem um efeito antimicrobiano comparável ou superior à fluoroquinolona na forma livre, mas parecem ter uma via de translocação diferente, independente de porinas. Estas diferenças no mecanismo de captura podem ser fundamentais para contornar a resistência bacteriana. De forma a compreender o papel dos lípidos no mecanismo de entrada dos metaloantibióticos, estudou-se a interação e localização dos metaloantibióticos da Ciprofloxacina (2ª geração), da Levofloxacina (3ª geração) e Moxifloxacina (4ª geração) com um modelo de membranas de Escherichia coli desprovido de porinas. Estes estudos foram realizados através de técnicas de espectroscopia de fluorescência, por medições em modo estacionário e resolvida no tempo. Os coeficientes de partição determinados demonstraram uma interação mais elevada dos metaloantibióticos relativamente às respetivas fluoroquinolonas na forma livre, um facto que está diretamente relacionado com as espécies existentes em solução a pH fisiológico. Os estudos de localização mostraram que estes metaloantibióticos devem estar inseridos na membrana bacteriana, confirmando a sua entrada independente de porinas. Este mecanismo de entrada, pela via hidrofóbica, é potenciado por interações eletrostáticas entre as espécies catiónicas de metaloantibiótico que existem a pH 7,4 e os grupos carregados negativamente dos fosfolípidos da membrana. Desta forma, os resultados obtidos neste estudo sugerem que a via de entrada dos metaloantibióticos e das respetivas fluoroquinolonas deve ser diferente. Os metaloantibióticos são candidatos adequados para a realização de mais testes laboratoriais e uma alternativa promissora para substituir as fluoroquinolonas convencionais, uma vez que parecem ultrapassar um dos principais mecanismos de resistência bacteriana a esta classe de antibióticos.

Simvastatin improves the healing of infected skin wounds of rats

This study explores the potential of the simvastatin to ameliorate inflammation and infection in open infected skin wounds of rats. Methods: Fourteen Wistar rats weighing 285±12g were used. The study was done in a group whose open infected skin wounds were treated with topical application of sinvastatina microemulsion (SIM, n=7) and a second group with wounds treated with saline 0.9 % (SAL, n=7). A bacteriological exam of the wounds fluid for gram positive and gram negative bacteria, the tecidual expression of TNFá and IL-1â by imunohistochemical technique, and histological analysis by HE stain were performed. Results: The expression of TNFa could be clearly demonstrated in lower degree in skin wounds treated with simvastatin (668.6 ± 74.7 ìm2) than in saline (2120.0 ± 327.1 ìm2). In comparison, wound tissue from SIM group displayed leukocyte infiltration significantly lower than that observed in SAL group (p<0.05). Culture results of the samples taken from wound fluid on fourth post treatment day revealed wound infection in only one rat of group simvastatin (SIM), where Proteus mirabilis, Escherchia coli and Enterobacter sp were isolated. In the rats whose wounds were treated with saline (SAL), polymicrobial infection with more than 100,000 CFU/g was detected in all the wounds. Conclusion: In addition to its antiinflammatory properties, the protective effects of simvastatin in infected open skin wounds is able to reduce infection and probably has antibacterial action. The potential to treat these wounds with statins to ameliorate inflammation and infection is promising

Bioinformatics analysis of the Pedobacter sp. NL19 genome

The last decades of the 20th century defined the genetic engineering advent, climaxing in the development of techniques, such as PCR and Sanger sequencing. This, permitted the appearance of new techniques to sequencing whole genomes, identified as next-generation sequencing. One of the many applications of these techniques is the in silico search for new secondary metabolites, synthesized by microorganisms exhibiting antimicrobial properties. The peptide antibiotics compounds can be classified in two classes, according to their biosynthesis, in ribosomal or nonribosomal peptides. Lanthipeptides are the most studied ribosomal peptides and are characterized by the presence of lanthionine and methylanthionine that result from posttranslational modifications. Lanthipeptides are divided in four classes, depending on their biosynthetic machinery. In class I, a LanB enzyme dehydrate serine and threonine residues in the C-terminus precursor peptide. Then, these residues undergo a cyclization step performed by a LanC enzyme, forming the lanthionine rings. The cleavage and the transport of the peptide is achieved by the LanP and LanT enzymes, respectively. Although, in class II only one enzyme, LanM, is responsible for the dehydration and cyclization steps and also only one enzyme performs the cleavage and transport, LanT. Pedobacter sp. NL19 is a Gram-negative bacterium, isolated from sludge of an abandon uranium mine, in Viseu (Portugal). Antibacterial activity in vitro was detected against several Gram-positive and Gram-negative bacteria. Sequencing and in silico analysis of NL19 genome revealed the presence of 21 biosynthetic clusters for secondary metabolites, including nonribosomal and ribosomal peptides biosynthetic clusters. Four lanthipeptides clusters were predicted, comprising the precursor peptides, the modifying enzymes (LanB and LanC), and also a bifunctional LanT. This result revealed the hybrid nature of the clusters, comprising characteristics from two distinct classes, which are poorly described in literature. The phylogenetic analysis of their enzymes showed that they clustered within the bacteroidetes clade. Furthermore, hybrid gene clusters were also found in other species of this phylum, revealing that it is a common characteristic in this group. Finally, the analysis of NL19 colonies by MALDI-TOF MS allowed the identification of a 3180 Da mass that corresponds to the predicted mass of a lanthipeptide encoded in one of the clusters. However, this result is not fully conclusive and further experiments are needed to understand the full potential of the compounds encoded in this type of clusters. In conclusion, it was determined that NL19 strain has the potential to produce diverse secondary metabolites, including lanthipeptides that were not functionally characterized so far.

An intimate link between antimicrobial peptide sequence diversity and binding to essential components of bacterial membranes

Antimicrobial peptides and proteins (AMPs) are widespread in the living kingdom. They are key effectors of defense reactions and mediators of competitions between organisms. They are often cationic and amphiphilic, which favors their interactions with the anionic membranes of microorganisms. Several AMP families do not directly alter membrane integrity but rather target conserved components of the bacterial membranes in a process that provides them with potent and specific antimicrobial activities. Thus, lipopolysaccharides (LPS), lipoteichoic acids (LTA) or the peptidoglycan precursor Lipid II are targeted by a broad series of AMPs. Studying the functional diversity of immune effectors tells us about the essential residues involved in AMP mechanism of action. Marine invertebrates have been found to produce a remarkable diversity of AMPs. Molluscan defensins and crustacean anti-LPS factors (ALF) are diverse in terms of amino acid sequence and show contrasted phenotypes in terms of antimicrobial activity. Their activity is directed essentially against Gram-positive or Gram-negative bacteria due their specific interactions with Lipid II or Lipid A, respectively. Through those interesting examples, we discuss here how sequence diversity generated throughout evolution informs us on residues required for essential molecular interaction at the bacterial membranes and subsequent antibacterial activity. Through the analysis of molecular variants having lost antibacterial activity or shaped novel functions, we also discuss the molecular bases of functional divergence in AMPs.

Chromatographic techniques to obtain the biomolecules profile of wild Suillus granulates

In recent years the interest in naturally occurring compounds has been increasing worldwide. Indeed, many of the bioactive compounds currently used as medicines have been synthesized based on the structure of natural compounds [1]. In order to obtain bioactive fractions and subsequently isolated compounds derived from natural matrices, several procedures have been carried out. One of these is to separate and assess the concentration of the active compound(s) present in the samples, a step in which the chromatographic techniques stand out [2]. In the present work the mushroom Sui/Ius granulatus (L.) Roussel was chemically characterized by chromatographic techniques coupled to different detectors, in order to evaluate the presence of nutritional and/or bioactive molecules. Some hydrophilic compounds, namely free sugars, were identified by high performance liquid chromatography coupled to a refraction index detector (HPLC-RI), and organic and phenolic acids were assessed by HPLC coupled to a photodiode array detector (HPLC-PDA). Regarding lipophilic compounds, fatty acids weredetermined by gas chromatography with a flame ionization detector (GC-FID) and tocopherols by HPLC-fluorescence detection. Mannitol and trehalose were the main free sugars detected. Different organic acids were also identified (i.e. oxalic, quinic and fumaric acids), as well as phenolic acids (i.e. gallic and p-hydroxybenzoic acids) and the related compound cinnamic acid. Mono- and polyunsaturated fatty acids were the prevailing fatty acids and a-, ~- and ~-tocopherol were the isoforms of vitamin E detected in the samples. Since this species proved to be a source of biologically active compounds, the antioxidant and antimicrobial properties were evaluated. The antioxidant activity was measured through the reducing power, free radical's scavenging activity and lipid peroxidation inhibition of its methanolic extract, and the antimicrobial activity was also tested in Gram positive and Gram negative bacteria and iri different fungi. S. granulatus presented antioxidant properties in all the performed assays, and proved to inhibit the growth of different bacterial and fungal strains. This study is a first step for classifying S. granulatus as a functional food, highlighting the potential of mushrooms as a source of nutraceutical and biologically active compounds.