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Lucio Veracabrera - One of the best experts on this subject based on the ideXlab platform.

  • genomic changes associated with the loss of Nocardia brasiliensis virulence in mice after 200 in vitro passages
    Infection and Immunity, 2016
    Co-Authors: Carolina Gonzalezcarrillo, Oliverio Welsh, Jorge Ocampocandiani, Rocio Ortizlopez, Ramiro Elizondogonzalez, Hector G Lozanogarza, Cassandra Millansauceda, Lucio Veracabrera
    Abstract:

    Nocardia species, particularly Nocardia brasiliensis, are etiologic agents of mycetoma, a chronic subcutaneous infection. Until now, little has been known about the pathogenic mechanisms involved in Nocardial infection. Traditionally, subculture in rich media has been a simple way to induce attenuation. In this work, we report the changes in virulence toward mice and in genomic constitution of N. brasiliensis produced after 200 continuous subcultures in brain heart infusion (BHI) medium (P-200 strain). The ability of the N. brasiliensis P-200 strain to produce experimental infection was tested using BALB/c mice. P-200 was also used to immunize mice to determine whether it could induce resistance against a challenge with a nonsubcultured isolate (P-0). Comparative proteomic analysis between N. brasiliensis P-0 and P-200 was performed by two-dimensional (2-D) electrophoresis, and the genome sequence was obtained through Roche 454 sequence analysis. Virulence in BALB/c mice was completely lost, and BALB/c mice immunized with P-200 bacterial cells were resistant to mycetoma production by the nonsubcultured strain. Whole-genome sequence analysis revealed that P-200 lost a total of 262,913 bp distributed in 19 deleted regions, involving a total of 213 open reading frames (ORFs). The deleted genes included those encoding bacterial virulence factors, e.g., catalase, nitrate reductase enzymes, and a group of mammalian cell entry (MCE) family proteins, which may explain the loss of virulence of the isolate. Thus, completely attenuated N. brasiliensis was obtained after 200 passages in BHI medium, and putative Nocardia virulence genes were identified for the first time.

  • in vivo activity of the benzothiazinones pbtz169 and btz043 against Nocardia brasiliensis
    PLOS Neglected Tropical Diseases, 2015
    Co-Authors: Norma Alejandra Gonzalezmartinez, Jorge Ocampocandiani, Hector G Lozanogarza, Stewart T Cole, Norma Cavazosrocha, Jorge Castrogarza, Alexandra De Osiocortez, Javier Vargasvillarreal, V A Makarov, Lucio Veracabrera
    Abstract:

    Background Mycetoma is a neglected, chronic, and deforming infectious disease caused by fungi and actinomycetes. In Mexico, N. brasiliensis is the predominant etiologic agent. Therapeutic alternatives are necessary because the current drug regimens have several disadvantages. Benzothiazinones (BTZ) are a new class of candidate drugs that inhibit decaprenylphosphoribose- epimerase (DprE1), an essential enzyme involved in the cell wall biosynthesis of Corynebacterineae. Methodology/Principal findings In this study, the in vitro activity of the next generation BTZ, PBTZ169, was tested against thirty Nocardia brasiliensis isolates. The MIC50 and MIC90 values for PBTZ169 were 0.0075 and 0.03 mu g/mL, respectively. Because Nocardia is a potential intracellular bacterium, a THP-1 macrophage monolayer was infected with N. brasiliensis HUJEG-1 and then treated with PBTZ169, resulting in a decrease in the number of colony-forming units (CFUs) at a concentration of 0.25X the in vitro value. The in vivo activity was evaluated after infecting female BALB/c mice in the right hind food-pad. After 6 weeks, treatment was initiated with PBTZ169 and its activity was compared with the first generation compound, BTZ043. Both BTZ compounds were administered at 100 mg/kg twice daily by gavage, and sulfamethoxazole/trimethoprim (SXT), at 100 mg/kg sulfamethoxazole, was used as a positive control. After 22 weeks of therapy, only PBTZ169 and SXT displayed statistically significant activity. Conclusion These results indicate that DprE1 inhibitors may be useful for treating infections of Nocardia and may therefore be active against other actinomycetoma agents. We must test combinations of these compounds with other antimicrobial agents, such as linezolid, tedizolid or SXT, that have good to excellent in vivo activity, as well as new DprE1 inhibitors that can achieve higher plasma levels.

  • complete genome sequence analysis of Nocardia brasiliensis hujeg 1 reveals a saprobic lifestyle and the genes needed for human pathogenesis
    PLOS ONE, 2013
    Co-Authors: Lucio Veracabrera, Rocio Ortizlopez, Ramiro Elizondogonzalez, Jorge Ocampocandiani
    Abstract:

    Nocardia brasiliensis is an important etiologic agent of mycetoma. These bacteria live as a saprobe in soil or organic material and enter the tissue via minor trauma. Mycetoma is characterized by tumefaction and the production of fistula and abscesses, with no spontaneous cure. By using mass sequencing, we determined the complete genomic nucleotide sequence of the bacteria. According to our data, the genome is a circular chromosome 9,436,348-bp long with 68% G+C content that encodes 8,414 proteins. We observed orthologs for virulence factors, a higher number of genes involved in lipid biosynthesis and catabolism, and gene clusters for the synthesis of bioactive compounds, such as antibiotics, terpenes, and polyketides. An in silico analysis of the sequence supports the conclusion that the bacteria acquired diverse genes by horizontal transfer from other soil bacteria, even from eukaryotic organisms. The genome composition reflects the evolution of bacteria via the acquisition of a large amount of DNA, which allows it to survive in new ecological niches, including humans.

  • Nocardia brasiliensis cell wall lipids modulate macrophage and dendritic responses that favor development of experimental actinomycetoma in balb c mice
    Infection and Immunity, 2012
    Co-Authors: Humberto J Trevinovillarreal, Lucio Veracabrera, Pedro L Valeroguillen, Mario C Salinascarmona
    Abstract:

    Nocardia brasiliensis is a Gram-positive facultative intracellular bacterium frequently isolated from human actinomycetoma. However, the pathogenesis of this infection remains unknown. Here, we used a model of bacterial delipidation with benzine to investigate the role of N. brasiliensis cell wall-associated lipids in experimental actinomycetoma. Delipidation of N. brasiliensis with benzine resulted in complete abolition of actinomycetoma without affecting bacterial viability. Chemical analyses revealed that trehalose dimycolate and an unidentified hydrophobic compound were the principal compounds extracted from N. brasiliensiswith benzine. By electron microscopy, the extracted lipids were found to be located in the outermost membrane layer of the N. brasiliensis cell wall. They also appeared to confer acid-fastness. In vitro, the extractable lipids from the N. brasiliensis cell wall induced the production of the proinflammatory cytokines interleukin-1(IL-1), IL-6, and CCL-2 in macrophages. The N. brasiliensis cell wall extractable lipids inhibited important macrophage microbicidal effects, such as tumor necrosis factor alpha (TNF-) and nitric oxide (NO) production, phagocytosis, bacterial killing, and major histocompatibility complex class II (MHCII) expression in response to gamma interferon (IFN-). In dendritic cells (DCs), N. brasiliensis cell wall-associated extractable lipids suppressed MHC-II, CD80, and CD40 expression while inducing tumor growth factor (TGF-) production. Immunization with delipidated N. brasiliensis induced partial protection preventing actinomycetoma. These findings suggest that N. brasiliensis cell wall-associated lipids are important for actinomycetoma development by inducing inflammation and modulating the responses of macrophages and DCs to N. brasiliensis.

  • in vitro activities of the new antitubercular agents pa 824 and btz043 against Nocardia brasiliensis
    Antimicrobial Agents and Chemotherapy, 2012
    Co-Authors: Lucio Veracabrera, Jorge Ocampocandiani, Mayra Paola Camposrivera, Norma Alejandra Gonzalezmartinez, Stewart T Cole
    Abstract:

    The in vitro activity of PA-824 and BTZ043 against 30 Nocardia brasiliensis isolates was tested. The MIC50 and MIC90 values for PA-824 were both >64 μg/ml. The same values for BTZ043 were 0.125 and 0.250 μg/ml. Given the MIC values for benzothiazinone (BTZ) compounds, we consider them good candidates to be tested in vivo against N. brasiliensis.

Mario C Salinascarmona - One of the best experts on this subject based on the ideXlab platform.

  • inducible nitric oxide synthase blockade with aminoguanidine protects mice infected with Nocardia brasiliensis from actinomycetoma development
    PLOS Neglected Tropical Diseases, 2020
    Co-Authors: Mario C Salinascarmona, Ossian Longorialozano, Humberto R Garzaesquivel, Juan Lopezulloa, Jorge Reyescarrillo, Anna V Vazquezmarmolejo
    Abstract:

    Mycetoma is a chronic infectious disease that can be caused by fungi or bacteria, Madurella mycetomatis and Nocardia brasiliensis are frequent etiologic agents of this disease. Mycetoma produced by bacteria is known as actinomycetoma. In mycetoma produced by fungi (eumycetoma) and actinomycetoma, diagnosis of the disease is based on clinical findings: severe inflammation, with deformities of affected tissues, abscesses, fistulae, sinuses and discharge of purulent material that contains micro colonies of the etiologic agent. Microscopic examination of infected tissue is similar regardless of the offending microbe; hallmark of infected tissue is severe inflammation with abundant neutrophils around micro colonies and granuloma formation with macrophages, lymphocytes, dendritic and foamy cells. Even though medical treatment is available for mycetoma patients, amputation, or surgical intervention is frequently needed. The pathogenesis of actinomycetoma is little known, most information was obtained from experimental animal models infected with bacteria. In other experimental mice infections with different microbes, it was demonstrated that nitric oxide is responsible for the intracellular killing of Mycobacterium tuberculosis by activated macrophages. Nitric oxide is a free radical with potent stimulatory and suppressive effects in innate and adaptive immunity. The unstable nitric oxide molecule is produced by action of nitric oxide synthases on L-arginine. There are three nitric oxide synthases expressed in different cells and tissues, two are constitutively expressed one in neurons, and the other in endothelial cells and one that is inducible in macrophages. Aminoguanidine is a competitive inhibitor of inducible nitric oxide synthase. Its administration in experimental animals may favor or harm them. We used aminoguanidine in mice infected with Nocardia brasiliensis, and demonstrated that all treated animals were protected from actinomycetoma development. Anti N. brasiliensis antibodies and T cell proliferation were not affected, but inflammation was reduced.

  • Nocardia brasiliensis induces formation of foamy macrophages and dendritic cells in vitro and in vivo
    PLOS ONE, 2014
    Co-Authors: Irene Meester, Adrian G Rosastaraco, Mario C Salinascarmona
    Abstract:

    Foamy cells have been described in various infectious diseases, for example in actinomycetoma induced by Nocardia brasiliensis. These cells are generally considered to be macrophages, although they present dendritic cell (DC)-specific surface markers. In this study, we determined and confirmed the lineage of possible precursors of foamy cells in vitro and in vivo using an experimental actinomycetoma model in BALB/c mice. Bone marrow-derived macrophages (BMDM) or DC (BMDC) were infected in vitro with N. brasiliensis or labeled with carboxyfluorescein diacetate succinimidyl ester (CFSE). Both, macrophages and DC, differentiated into foamy cells after in vitro infection. CFSE-labeled BMDM or BMDC were tested for phagocytosis and CD11c/CD11b receptors markers expression before being transferred into the actinomycetoma lesion site of infected mice. In vivo studies showed that BMDM and BMDC were traced at the site where foamy cells are present in the experimental actinomycetoma. Interestingly, many of the transferred BMDM and BMDC were stained with the lipid-droplet fluorophore Nile Red. In conclusion, macrophages and DC cells can be differentiated into foamy cells in vitro and in vivo during N. brasiliensis infection.

  • retnla down regulation and il 13 rich environment correlate with inflammation severity in experimental actinomycetoma by Nocardia brasiliensis
    Pathogens and Disease, 2013
    Co-Authors: Irene Meester, Adrian G Rosastaraco, Mario C Salinascarmona
    Abstract:

    Nocardia brasiliensis (Nb) is a facultative intracellular pathogen that may cause actinomycetoma when immune response is unable to control the pathogenic invasion. We used comparative real-time PCR to evaluate the expression level of molecules indicative of either classical or alternative activation of macrophages, as well as of cytokines involved in macrophage polarization, during the experimental infection in BALB/c mice. We found induction or increased expression of the pro-inflammatory markers csf2/GM-CSF, interferon-gamma, and nos2/iNOS. The expression of Ym1 and IL-13, which are usually related with alternative activation of macrophage, was also increased. However, retnla/FIZZ1 expression decreased sharply during the infection. We concluded that Nb infection induces both a pro-inflammatory and anti-inflammatory environment, in which there is a strong inverse correlation between IL-13 and retnla expression.

  • retnla down regulation and il 13 rich environment correlate with inflammation severity in experimental actinomycetoma by Nocardia brasiliensis
    Pathogens and Disease, 2013
    Co-Authors: Irene Meester, Adrian G Rosastaraco, Mario C Salinascarmona
    Abstract:

    AbstractNocardia brasiliensis (Nb) is a facultative intracellular pathogen that may causeactinomycetoma when immune response is unable to control the pathogenicinvasion. We used comparative real-time PCR to evaluate the expression level ofmolecules indicative of either classical or alternative activation of macrophages, aswell as of cytokines involved in macrophage polarization, during the experimentalinfection in BALB/c mice. We found induction or increased expression of the pro-inflammatory markers csf2/GM-CSF, interferon-gamma, and nos2/iNOS. Theexpression of Ym1 and IL-13, which are usually related with alternative activationof macrophage, was also increased. However, retnla/FIZZ1 expression decreasedsharply during the infection. We concluded that Nb infection induces both a pro-inflammatory and anti-inflammatory environment, in which there is a strong inversecorrelation between IL-13 and retnla expression. Introduction The actinomycete Nocardia brasiliensis (Nb) is a gram-positive, acid-fast, aerobic saprophyte that forms branchinghyphae during growth. Accidental, traumatic infection viathe skin may lead to a cutaneous actinomycetoma, whichmay extend to and destroy neighboring tissues. Within thehost, Nb is able to multiply both intracellularly, withinmacrophages, and extracellularly, forming grains that maydrain from fistules in the lesion leaving behind fibroticlesions. At a histopathological level, multilocular microab-scesses contain a central bacterial grain, which is sur-rounded by abundant leukocytes, mainly neutrophils, butalso lymphocytes and macrophages. Foamy macrophagesare found just below the fibrotic layer that delimits amicroabscess (Salinas-Carmona, 2000). To study host–pathogen interactions, we have established an experimentalactinomycetoma in BALB/c mice, which is similar to thehuman lesion (Salinas-Carmona et al., 1999). Typically, thelesion size of the acute inflammation reaches its maximumabout 1 week after inoculation. The chronic infection(actinomycetoma) develops after 4 weeks with a severeinflammation and tissue deformation (Salinas-Carmonaet al., 1999).The local presence of interleukin (IL)-12 and interferon-gamma (IFN-c) (Solis-Soto et al., 2008; Rosas-Taracoet al., 2012) indicates the activation of a Th1 cellularimmune response. The humoral immune response is alsoactivated, in which, apart from IgG antibodies, relativelyhigh sustained levels of IgM antibodies seem important for

  • Nocardia brasiliensis cell wall lipids modulate macrophage and dendritic responses that favor development of experimental actinomycetoma in balb c mice
    Infection and Immunity, 2012
    Co-Authors: Humberto J Trevinovillarreal, Lucio Veracabrera, Pedro L Valeroguillen, Mario C Salinascarmona
    Abstract:

    Nocardia brasiliensis is a Gram-positive facultative intracellular bacterium frequently isolated from human actinomycetoma. However, the pathogenesis of this infection remains unknown. Here, we used a model of bacterial delipidation with benzine to investigate the role of N. brasiliensis cell wall-associated lipids in experimental actinomycetoma. Delipidation of N. brasiliensis with benzine resulted in complete abolition of actinomycetoma without affecting bacterial viability. Chemical analyses revealed that trehalose dimycolate and an unidentified hydrophobic compound were the principal compounds extracted from N. brasiliensiswith benzine. By electron microscopy, the extracted lipids were found to be located in the outermost membrane layer of the N. brasiliensis cell wall. They also appeared to confer acid-fastness. In vitro, the extractable lipids from the N. brasiliensis cell wall induced the production of the proinflammatory cytokines interleukin-1(IL-1), IL-6, and CCL-2 in macrophages. The N. brasiliensis cell wall extractable lipids inhibited important macrophage microbicidal effects, such as tumor necrosis factor alpha (TNF-) and nitric oxide (NO) production, phagocytosis, bacterial killing, and major histocompatibility complex class II (MHCII) expression in response to gamma interferon (IFN-). In dendritic cells (DCs), N. brasiliensis cell wall-associated extractable lipids suppressed MHC-II, CD80, and CD40 expression while inducing tumor growth factor (TGF-) production. Immunization with delipidated N. brasiliensis induced partial protection preventing actinomycetoma. These findings suggest that N. brasiliensis cell wall-associated lipids are important for actinomycetoma development by inducing inflammation and modulating the responses of macrophages and DCs to N. brasiliensis.

Oliverio Welsh - One of the best experts on this subject based on the ideXlab platform.

  • genomic changes associated with the loss of Nocardia brasiliensis virulence in mice after 200 in vitro passages
    Infection and Immunity, 2016
    Co-Authors: Carolina Gonzalezcarrillo, Oliverio Welsh, Jorge Ocampocandiani, Rocio Ortizlopez, Ramiro Elizondogonzalez, Hector G Lozanogarza, Cassandra Millansauceda, Lucio Veracabrera
    Abstract:

    Nocardia species, particularly Nocardia brasiliensis, are etiologic agents of mycetoma, a chronic subcutaneous infection. Until now, little has been known about the pathogenic mechanisms involved in Nocardial infection. Traditionally, subculture in rich media has been a simple way to induce attenuation. In this work, we report the changes in virulence toward mice and in genomic constitution of N. brasiliensis produced after 200 continuous subcultures in brain heart infusion (BHI) medium (P-200 strain). The ability of the N. brasiliensis P-200 strain to produce experimental infection was tested using BALB/c mice. P-200 was also used to immunize mice to determine whether it could induce resistance against a challenge with a nonsubcultured isolate (P-0). Comparative proteomic analysis between N. brasiliensis P-0 and P-200 was performed by two-dimensional (2-D) electrophoresis, and the genome sequence was obtained through Roche 454 sequence analysis. Virulence in BALB/c mice was completely lost, and BALB/c mice immunized with P-200 bacterial cells were resistant to mycetoma production by the nonsubcultured strain. Whole-genome sequence analysis revealed that P-200 lost a total of 262,913 bp distributed in 19 deleted regions, involving a total of 213 open reading frames (ORFs). The deleted genes included those encoding bacterial virulence factors, e.g., catalase, nitrate reductase enzymes, and a group of mammalian cell entry (MCE) family proteins, which may explain the loss of virulence of the isolate. Thus, completely attenuated N. brasiliensis was obtained after 200 passages in BHI medium, and putative Nocardia virulence genes were identified for the first time.

  • Systemic increased immune response to Nocardia brasiliensis co-exists with local immunosuppressive microenvironment
    Antonie van Leeuwenhoek, 2012
    Co-Authors: Mario C. Salinas-carmona, Adrian Geovanni Rosas-taraco, Oliverio Welsh
    Abstract:

    Human diseases produced by pathogenic actinomycetes are increasing because they may be present as opportunistic infections. Some of these microbes cause systemic infections associated with immunosuppressive conditions, such as chemotherapy for cancer, immunosuppressive therapy for transplant, autoimmune conditions, and AIDS; while others usually cause localized infection in immunocompetent individuals. Other factors related to this increase in incidence are: antibiotic resistance, not well defined taxonomy, and a delay in isolation and identification of the offending microbe. Examples of these infections are systemic disease and brain abscesses produced by Nocardia asteroides or the located disease by Nocardia brasiliensis , named actinomycetoma. During the Pathogenic Actinomycetes Symposium of the 16th International Symposium on Biology of Actinomycetes (ISBA), held in Puerto Vallarta, Mexico, several authors presented recent research on the mechanisms by which N. brasiliensis modulates the immune system to survive in the host and advances in medical treatment of human actinomycetoma. Antibiotics and antimicrobials that are effective against severe actinomycetoma infections with an excellent therapeutic outcome and experimental studies of drugs that show promising bacterial inhibition in vivo and in vitro were presented. Here we demonstrate a systemic strong acquired immune response in humans and experimental mice at the same time of a local dominance of anti inflammatory cytokines environment. The pathogenic mechanisms of some actinomycetes include generation of an immunosuppressive micro environment to evade the protective immune response. This information will be helpful in understanding pathogenesis and to design new drugs for treatment of actinomycetoma.

  • decrease of virulence for balb c mice produced by continuous subculturing of Nocardia brasiliensis
    BMC Infectious Diseases, 2011
    Co-Authors: Janeth A Almaguerchavez, Salvador Saidfernandez, Oliverio Welsh, Jorge Ocampocandiani, Hector G Lozanogarza, Viktor J Romerodiaz, Lucio Veracabrera
    Abstract:

    Subculturing has been extensively used to attenuate human pathogens. In this work we studied the effect of continuous subculturing of Nocardia brasiliensis HUJEG-1 on virulence in a murine model. Nocardia brasiliensis HUJEG-1 was subcultured up to 130 times on brain heart infusion over four years. BALB/c mice were inoculated in the right foot pad with the bacteria subcultured 0, 40, 80, 100 and 130 times (T0, T40, T80 T100 and T130). The induction of resistance was tested by using T130 to inoculate a group of mice followed by challenge with T0 12 weeks later. Biopsies were taken from the newly infected foot-pad and immunostained with antibodies against CD4, CD8 and CD14 in order to analyze the in situ immunological changes. When using T40, T80 T100 and T130 as inoculums we observed lesions in 10, 5, 0 and 0 percent of the animals, respectively, at the end of 12 weeks. In contrast, their controls produced mycetoma in 80, 80, 70 and 60% of the inoculated animals. When studying the protection of T130, we observed a partial resistance to the infection. Immunostaining revealed an intense CD4+ lymphocytic and macrophage infiltrate in healing lesions. After 130 in vitro passages of N. brasiliensis HUJEG-1 a severe decrease in its virulence was observed. Immunization of BALB/c mice, with these attenuated cells, produced a state of partial resistance to infection with the non-subcultured isolate.

  • evaluation of the combined therapy of da 7218 a new oxazolidinone and trimethoprim sulfamethoxazole in the treatment of experimental actinomycetoma by Nocardia brasiliensis
    Current Drug Delivery, 2010
    Co-Authors: Nelly Alejandra Espinozagonzalez, Salvador Saidfernandez, Sunghak Choi, Gerardo Lozanogarza, Oliverio Welsh, Jorge Ocampocandiani, Lucio Veracabrera
    Abstract:

    Objectives: Currently, for actinomycetoma, combined antimicrobial therapy is preferred to the use of a single compound. This is in order to provide a broader-spectrum coverage due to a combinatory or synergistic effect between the drugs, and to decrease the possibility of emergence of natural resistant strains. A new oxazolidinone pro-drug, DA-7218 [(R)-3-(4-(2-(2-methyltetrazol-5-yl)-pyridin-5-yl)-3-fluorophenyl)-2-oxo-5-oxazolidinyl) methyl-disodium-phosphate] (recently re-named TR-701), has shown very good in vitro and in vivo activities against several gram-positive bacteria including Nocardia spp. Methods: In the present work we evaluated the effect of DA-7218 at two different doses, alone and combined with trimethoprim/ sulfamethoxazole (SXT), in an experimental Nocardia brasiliensis actinomycetoma murine model. We also included a negative and a positive control group (linezolid and saline solution respectively). Results: At the end of the treatment period, we observed a clinically and statistically significant difference among the drug receiving groups (combined, alone and linezolid) and the control group (P=0.004). The difference was higher (P= 0.004) between the groups receiving DA-7218 (25mg/kg) alone or combined with SXT, and the control group (saline solution). Conclusions: In this work we proved that DA-7218 alone and combined with SXT is effective in the treatment of experimental actinomycetoma by Nocardia brasiliensis and that it could be potentially useful in the treatment of human actinomycetoma.

  • in vitro activity of ach 702 a new isothiazoloquinolone against Nocardia brasiliensis compared with econazole and the carbapenems imipenem and meropenem alone or in combination with clavulanic acid
    Antimicrobial Agents and Chemotherapy, 2010
    Co-Authors: Lucio Veracabrera, Jorge Ocampocandiani, Mayra Paola Camposrivera, Wendy G Escalantefuentes, Michael J Pucci, Oliverio Welsh
    Abstract:

    The in vitro activities of ACH-702 and other antimicrobials against 30 Nocardia brasiliensis isolates were tested. The MIC(50) (MIC for 50% of the strains tested) and MIC(90) values of ACH-702 were 0.125 and 0.5 microg/ml. The same values for econazole were 2 and 4 microg/ml. The MIC(50) and MIC(90) values of imipenem and meropenem were 64 and >64 microg/ml and 2 and 8 microg/ml, respectively; the addition of clavulanic acid to the carbapenems had no effect.

Jorge Ocampocandiani - One of the best experts on this subject based on the ideXlab platform.

  • genomic changes associated with the loss of Nocardia brasiliensis virulence in mice after 200 in vitro passages
    Infection and Immunity, 2016
    Co-Authors: Carolina Gonzalezcarrillo, Oliverio Welsh, Jorge Ocampocandiani, Rocio Ortizlopez, Ramiro Elizondogonzalez, Hector G Lozanogarza, Cassandra Millansauceda, Lucio Veracabrera
    Abstract:

    Nocardia species, particularly Nocardia brasiliensis, are etiologic agents of mycetoma, a chronic subcutaneous infection. Until now, little has been known about the pathogenic mechanisms involved in Nocardial infection. Traditionally, subculture in rich media has been a simple way to induce attenuation. In this work, we report the changes in virulence toward mice and in genomic constitution of N. brasiliensis produced after 200 continuous subcultures in brain heart infusion (BHI) medium (P-200 strain). The ability of the N. brasiliensis P-200 strain to produce experimental infection was tested using BALB/c mice. P-200 was also used to immunize mice to determine whether it could induce resistance against a challenge with a nonsubcultured isolate (P-0). Comparative proteomic analysis between N. brasiliensis P-0 and P-200 was performed by two-dimensional (2-D) electrophoresis, and the genome sequence was obtained through Roche 454 sequence analysis. Virulence in BALB/c mice was completely lost, and BALB/c mice immunized with P-200 bacterial cells were resistant to mycetoma production by the nonsubcultured strain. Whole-genome sequence analysis revealed that P-200 lost a total of 262,913 bp distributed in 19 deleted regions, involving a total of 213 open reading frames (ORFs). The deleted genes included those encoding bacterial virulence factors, e.g., catalase, nitrate reductase enzymes, and a group of mammalian cell entry (MCE) family proteins, which may explain the loss of virulence of the isolate. Thus, completely attenuated N. brasiliensis was obtained after 200 passages in BHI medium, and putative Nocardia virulence genes were identified for the first time.

  • in vivo activity of the benzothiazinones pbtz169 and btz043 against Nocardia brasiliensis
    PLOS Neglected Tropical Diseases, 2015
    Co-Authors: Norma Alejandra Gonzalezmartinez, Jorge Ocampocandiani, Hector G Lozanogarza, Stewart T Cole, Norma Cavazosrocha, Jorge Castrogarza, Alexandra De Osiocortez, Javier Vargasvillarreal, V A Makarov, Lucio Veracabrera
    Abstract:

    Background Mycetoma is a neglected, chronic, and deforming infectious disease caused by fungi and actinomycetes. In Mexico, N. brasiliensis is the predominant etiologic agent. Therapeutic alternatives are necessary because the current drug regimens have several disadvantages. Benzothiazinones (BTZ) are a new class of candidate drugs that inhibit decaprenylphosphoribose- epimerase (DprE1), an essential enzyme involved in the cell wall biosynthesis of Corynebacterineae. Methodology/Principal findings In this study, the in vitro activity of the next generation BTZ, PBTZ169, was tested against thirty Nocardia brasiliensis isolates. The MIC50 and MIC90 values for PBTZ169 were 0.0075 and 0.03 mu g/mL, respectively. Because Nocardia is a potential intracellular bacterium, a THP-1 macrophage monolayer was infected with N. brasiliensis HUJEG-1 and then treated with PBTZ169, resulting in a decrease in the number of colony-forming units (CFUs) at a concentration of 0.25X the in vitro value. The in vivo activity was evaluated after infecting female BALB/c mice in the right hind food-pad. After 6 weeks, treatment was initiated with PBTZ169 and its activity was compared with the first generation compound, BTZ043. Both BTZ compounds were administered at 100 mg/kg twice daily by gavage, and sulfamethoxazole/trimethoprim (SXT), at 100 mg/kg sulfamethoxazole, was used as a positive control. After 22 weeks of therapy, only PBTZ169 and SXT displayed statistically significant activity. Conclusion These results indicate that DprE1 inhibitors may be useful for treating infections of Nocardia and may therefore be active against other actinomycetoma agents. We must test combinations of these compounds with other antimicrobial agents, such as linezolid, tedizolid or SXT, that have good to excellent in vivo activity, as well as new DprE1 inhibitors that can achieve higher plasma levels.

  • complete genome sequence analysis of Nocardia brasiliensis hujeg 1 reveals a saprobic lifestyle and the genes needed for human pathogenesis
    PLOS ONE, 2013
    Co-Authors: Lucio Veracabrera, Rocio Ortizlopez, Ramiro Elizondogonzalez, Jorge Ocampocandiani
    Abstract:

    Nocardia brasiliensis is an important etiologic agent of mycetoma. These bacteria live as a saprobe in soil or organic material and enter the tissue via minor trauma. Mycetoma is characterized by tumefaction and the production of fistula and abscesses, with no spontaneous cure. By using mass sequencing, we determined the complete genomic nucleotide sequence of the bacteria. According to our data, the genome is a circular chromosome 9,436,348-bp long with 68% G+C content that encodes 8,414 proteins. We observed orthologs for virulence factors, a higher number of genes involved in lipid biosynthesis and catabolism, and gene clusters for the synthesis of bioactive compounds, such as antibiotics, terpenes, and polyketides. An in silico analysis of the sequence supports the conclusion that the bacteria acquired diverse genes by horizontal transfer from other soil bacteria, even from eukaryotic organisms. The genome composition reflects the evolution of bacteria via the acquisition of a large amount of DNA, which allows it to survive in new ecological niches, including humans.

  • in vitro activities of the new antitubercular agents pa 824 and btz043 against Nocardia brasiliensis
    Antimicrobial Agents and Chemotherapy, 2012
    Co-Authors: Lucio Veracabrera, Jorge Ocampocandiani, Mayra Paola Camposrivera, Norma Alejandra Gonzalezmartinez, Stewart T Cole
    Abstract:

    The in vitro activity of PA-824 and BTZ043 against 30 Nocardia brasiliensis isolates was tested. The MIC50 and MIC90 values for PA-824 were both >64 μg/ml. The same values for BTZ043 were 0.125 and 0.250 μg/ml. Given the MIC values for benzothiazinone (BTZ) compounds, we consider them good candidates to be tested in vivo against N. brasiliensis.

  • complete genome sequence of Nocardia brasiliensis hujeg 1
    Journal of Bacteriology, 2012
    Co-Authors: Lucio Veracabrera, Rocio Ortizlopez, Ramiro Elizondogonzalez, Antonio Ali Perezmaya, Jorge Ocampocandiani
    Abstract:

    In Mexico, actinomycetoma is mainly caused by Nocardia brasiliensis, which is a soil inhabitant actinobacterium. Here, we report for the first time the draft genome of a strain isolated from a human case that has largely been found in in vitro and experimental models of actinomycetoma, N. brasiliensis HUJEG-1.

Yuzuru Mikami - One of the best experts on this subject based on the ideXlab platform.

  • Unusually located lymphocutaneous nocardiosis caused by Nocardia brasiliensis.
    The British journal of dermatology, 2006
    Co-Authors: W. Naka, Yuzuru Mikami, Shunichi Miyakawa, H. Niizeki, Tomoo Fukuda, Takeji Nishikawa
    Abstract:

    We report a patient with primary lymphocutaneous Nocardia brasiliensis infection affecting the face and left arm. The mode of infection was via skin abrasions which occurred 2 weeks prior to the development of the skin lesions. Treatment with intravenous minocycline for 4 weeks resulted in a cure. We also review 12 previously reported Japanese cases of lymphocutaneous nocardiosis.

  • brasilibactin a a cytotoxic compound from actinomycete Nocardia brasiliensis
    Journal of Natural Products, 2005
    Co-Authors: Masashi Tsuda, Yuzuru Mikami, Yasushi Tanaka, Masaaki Yamakawa, Seiko Oka, Yasutake Hoshino, Ayumi Sato, Hironori Fujiwara, Yasushi Ohizumi, Jun'ichi Kobayashi
    Abstract:

    A new cytotoxic compound, brasilibactin A (1), has been isolated from the actinomycete Nocardia brasiliensis IFM 0995, and the structure was elucidated on the basis of spectroscopic data and chemical means.

  • brasilicardins b d new tricyclic terpernoids from actinomycete Nocardia brasiliensis
    Bioorganic & Medicinal Chemistry, 2004
    Co-Authors: Kazusei Komatsu, Yuzuru Mikami, Yasushi Tanaka, Masashi Tsuda, Motoo Shiro, Jun'ichi Kobayashi
    Abstract:

    Three new tricyclic terpenoids, brasilicardins B-D (2-4), were isolated together with brasilicardin A (1), a potent immunosuppressive compound, from the cultured broth of a pathogenic actinomycete Nocardia brasiliensis IFM0406, and the structures and stereochemistry were determined by spectroscopic data and a single crystal X-ray diffraction analysis. The immunosuppressive and cytotoxic activities of 2-4 were examined in the comparison with 1.

  • clinical isolates of Nocardia brasiliensis from japan exhibit variable susceptibility to the antibiotic imipenem
    Mycopathologia, 2004
    Co-Authors: Akiko Kageyama, Katsukiyo Yazawa, Yasutaka Hoshino, Masaharu Watanabe, Yuzuru Mikami
    Abstract:

    Clinical isolates of Nocardia brasiliensis from Japan were classified into two groups based on their susceptibility to the carbapenem antibiotic, imipenem (IPM). Of 33 strains tested, 10 belonged to an IPM susceptible group, with MIC of from 0.25 to 2 microg/ml and a MIC(80) value of 1.5 microg/ml for this antibiotic. The remaining 23 strains belonged to an IPM resistant group with MIC and MIC(80) values of 8-16 microg/ml and >16 microg/ml, respectively. The type strain of N. brasiliensis belonged to this resistant group. Analysis of 16S rDNA genes sequences showed that the IPM susceptible group had characteristic single nucleotide substitutions at positions 103 (T), 381 (A), and 456 (A), in contrast to the IPM resistant group. This grouping, however, was not associated with their clinical manifestation.

  • Nocardia brasiliensis infection seen on grafted skin of the dorsum of a foot
    Nippon Ishinkin Gakkai Zasshi, 2001
    Co-Authors: Manabu Maeda, Miki Sato, Yuko Tozaki, Yoko Okumura, Yuzuru Mikami
    Abstract:

    For the past 4 years a 23 y-old female has noticed erythema on the dorsum of the right foot, where skin was grafted due to a traffic accident 20 years ago. She visited the Department of Dermatology of Gifu Prefectural Hospital on Oct. 19, 1998; her general health was good. Physical examination disclosed a swelling with erythema, papules and pustules on the dorsum of the right foot. The results of routine laboratory investigations were within normal limits except for the white blood cell count (11, 300/mm3), blood sediment rate (25mm/hrs), C reactive protein (1.21) and rheumatoid factor (×16.6). Several yellowish and verrucous or wrinkled colonies were grown on Sabouraud's agar culture from the biopsied specimen of the foot.Histopathological features showed epidermal hyperplasia with elongation of rete ridges and granulomatous changes in the dermis; many mononuclear and giant cells were present, and several positive fine filamentous and irregularly branching structures with PAS and Grocott stains were seen in the granulomatous nests. Both clinical and histopathological features led to speculation of Nocardia infection, and Nocardia brasiliensis was determined. The patient was treated by surgical total resection including the grafted skin. Although a soybean-sized nodule was seen on the border of the skin-graft of the foot three months later, there was no recurrence after the local resection.