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1.
Tuberculosis (Edinb) ; 134: 102203, 2022 05.
Article in English | MEDLINE | ID: mdl-35367869

ABSTRACT

Cattle vaccination is an attractive approach in compliance with control and eradication programs against Bovine Tuberculosis (bTB). Today, there is no anti bTB vaccine licensed. Two vaccine candidates, MbΔmce2 and MbΔmce2-phoP previously designed were evaluated in BALB/c mice, including the parental M. bovis NCTC10772 and a M. bovis hypervirulent Mb04-303 strains as controls. Sentinel mice (non-inoculated) cohoused with subcutaneous inoculated mice. Persistence, visible tuberculosis lesions (VTL) in lungs and spleens and bacillary load were investigated subcutaneously delivered at 60 and 90 days after inoculation (dpi) as well as their potential transmission to naïve mice. While a 100% survival was observed at 90 dpi without VTL in all groups, transmission was not evidenced in the sentinels mice. Vaccine candidates and control strains were isolated from the spleen of all inoculated mice, while Mb04-303 was isolated from the lungs of one inoculated mouse. Vaccine candidate's attenuation considering survival, lung bacillary load and VTL was confirmed, administrated by the subcutaneous route. Future experiments are necessary to demonstrate whether the persistence of both mutants in the spleen, with low CFU, remains over time to increase the potential increasing risk of dissemination to organs and subsequent transmission to other animals by airborne or other routes.


Subject(s)
Mycobacterium bovis , Mycobacterium tuberculosis , Tuberculosis, Bovine , Tuberculosis , Animals , BCG Vaccine , Cattle , Disease Models, Animal , Mice , Mice, Inbred BALB C , Tuberculosis/prevention & control , Tuberculosis, Bovine/prevention & control
2.
J Pept Sci ; 25(3): e3149, 2019 Mar.
Article in English | MEDLINE | ID: mdl-30746861

ABSTRACT

Human pathogenic gram-negative bacteria, such as enteropathogenic Escherichia coli (EPEC), rely on type III secretion systems (T3SS) to translocate virulence factors directly into host cells. The coiled-coil domains present in the structural proteins of T3SS are conformed by amphipathic alpha-helical structures that play an important role in the protein-protein interaction and are essential for the assembly of the translocation complex. To investigate the inhibitory capacity of these domains on the T3SS of EPEC, we synthesized peptides between 7 and 34 amino acids based on the coiled-coil domains of proteins that make up this secretion system. This analysis was performed through in vitro hemolysis assays by assessing the reduction of T3SS-dependent red blood cell lysis in the presence of the synthesized peptides. After confirming its inhibitory capacity, we performed molecular modeling assays using combined techniques, docking-molecular dynamic simulations, and quantum-mechanic calculations of the various peptide-protein complexes, to improve the affinity of the peptides to the target proteins selected from T3SS. These techniques allowed us to demonstrate that the peptides with greater inhibitory activity, directed against the coiled-coil domain of the C-terminal region of EspA, present favorable hydrophobic and hydrogen bond molecular interactions. Particularly, the hydrogen bond component is responsible for the stabilization of the peptide-protein complex. This study demonstrates that compounds targeting T3SS from pathogenic bacteria can indeed inhibit bacterial infection by presenting a higher specificity than broad-spectrum antibiotics. In turn, these peptides could be taken as initial structures to design and synthesize new compounds that mimic their inhibitory pharmacophoric pattern.


Subject(s)
Anti-Bacterial Agents/pharmacology , Enteropathogenic Escherichia coli/drug effects , Enteropathogenic Escherichia coli/metabolism , Peptides/pharmacology , Type III Secretion Systems/drug effects , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/chemistry , Circular Dichroism , Enteropathogenic Escherichia coli/growth & development , Humans , Microbial Sensitivity Tests , Models, Molecular , Peptides/chemical synthesis , Peptides/chemistry , Thermodynamics
3.
Microorganisms ; 6(4)2018 Oct 27.
Article in English | MEDLINE | ID: mdl-30373243

ABSTRACT

Enterohemorrhagic Escherichia coli (EHEC) and enteropathogenic Escherichia coli (EPEC) are attaching and effacing (A/E) pathogens, which translocate effector proteins to intestinal enterocytes through a type III secretion system (T3SS). T3SS and most of its effector proteins are encoded in a pathogenicity island called LEE. Recently, new effectors have been located outside the LEE. This study aimed to characterize EspY3, a novel non-LEE encoded T3SS effector of EHEC. EspY3 shares homology with SopD and PipB2 effector proteins of Salmonella's T3SS-1 and T3SS-2, respectively. The presence of recombinant EspY3 in the supernatant samples demonstrated that EspY3 was secreted by the T3SS of EHEC and EPEC. Through infection assays, we demonstrated the translocation of EspY3 into Caco-2 cells by T3SS of EPEC. The subcellular localization of EspY3 was determined in the pedestal region, where its presence generates a significant increase in the size of the pedestals area. The EspY3 effector induced the elongation of polymerized actin pedestals in infected Caco-2 by EPEC. This study confirmed that EspY3 is part of the repertoire of T3SS effectors of EHEC O157:H7, and that it participates in modeling cellular actin during the infection.

4.
Rev. argent. microbiol ; Rev. argent. microbiol;49(4): 332-338, Dec. 2017. graf, tab
Article in English | LILACS | ID: biblio-958015

ABSTRACT

Background: Latent tuberculosis has been associated with the persistence of dormant Mycobacterium tuberculosis in the organism of infected individuals, who are reservoirs of the bacilli and the source for spreading the disease in the community. New active anti-TB drugs exerting their metabolic action at different stages and on latent/dormant bacilli are urgently required to avoid endogenous reactivations and to be part of treatments of multi- and extensively-drug resistant tuberculosis (M/XDR-TB). It was previously reported that azole drugs are active against M. tuberculosis. For that reason, the aims of this study were to determine the in vitro activity of azole drugs, imidazole (clotrimazole, CLO and econazole, ECO) and nitroimidazole (metronidazole, MZ and ipronidazole, IPZ), against a collection of MDR M. tuberculosis clinical isolates; and to analyze their potential use in both the LTB and the active forms of M/XDR-TB treatments. Methods: A total of 55 MDR M. tuberculosis isolates and H37Rv were included. MZ and IPZ activity against M. tuberculosis isolates were tested using anaerobic culture conditions. The activity of ECO and CLO was measured by the minimal inhibitory concentration (MIC) using a microdilution colorimetric method. Results: MZ and IPZ showed bacteriostatic activity against M. tuberculosis strains. MIC5o and MIC90 to ECO was 4.0 µg/ml, while MIC50 to CLO was 4.0 µg/ml and MIC90 was 8.0 µg/ml respectively. Conclusion: All azole compounds tested in the study showed inhibitory activity against MDR M. tuberculosis clinical isolates.


Introducción: La tuberculosis (TB) latente ha sido asociada a la persistencia de Mycobacterium tuberculosis durmientes en el organismo de las personas infectadas, las cuales constituyen un reservorio del bacilo y una fuente de diseminación de la enfermedad en la comunidad. Urge la necesidad de contar con nuevos fármacos antituberculosos con acción sobre el bacilo en estado latente/durmiente, a fin de evitar reactivaciones endógenas y para ser incluidas en el tratamiento de la TB multirresistente y extensivamente resistente (M/XDR-TB). Se ha reportado que los azoles son activos contra M. tuberculosis. Por esta razón, los objetivos del presente estudio fueron determinar la actividad in vitro sobre aislamientos clínicos de M/XDR-TB de distintos azoles, incluyendo los imidazoles econazol (ECO) y clotrimazol (CLO) y los 5-nitro-imidazoles ipronidazol (IPZ) y metronidazol (MZ), así como analizar su potencial uso contra las formas latente y activa de esta enfermedad. Métodos: Fueron incluidos 55 aislamientos clínicos de M. tuberculosis MDR y la cepa de referencia H37Rv. Se evaluó la actividad del MZ y el IPZ sobre los aislamientos en condiciones de cultivo anaeróbico, mientras que la actividad del ECO y el CLO fue estimada determinando la concentración inhibitoria mínima (CIM) mediante el método colorimétrico de microdilución en placa. Resultados: El MZ y el IPZ presentaron actividad bacteriostática frente a las cepas de M. tuberculosis. La CIM50 y CIM90 del ECO fue de 4 µg/ml, mientras que el CLO presentó una CIM50 de 4 µg/ml y una CIM90 de 8 µg/ml. Conclusión: Todos los compuestos azólicos evaluados presentaron actividad inhibitoria frente a aislamientos clínicos de M. tuberculosis.


Subject(s)
Humans , Azoles , Mycobacterium tuberculosis , Antitubercular Agents , Azoles/pharmacology , Tuberculosis , Microbial Sensitivity Tests , Tuberculosis, Multidrug-Resistant/drug therapy , Mycobacterium tuberculosis/drug effects , Antitubercular Agents/pharmacology
5.
Rev Argent Microbiol ; 49(4): 332-338, 2017.
Article in English | MEDLINE | ID: mdl-28919150

ABSTRACT

BACKGROUND: Latent tuberculosis has been associated with the persistence of dormant Mycobacterium tuberculosis in the organism of infected individuals, who are reservoirs of the bacilli and the source for spreading the disease in the community. New active anti-TB drugs exerting their metabolic action at different stages and on latent/dormant bacilli are urgently required to avoid endogenous reactivations and to be part of treatments of multi- and extensively-drug resistant tuberculosis (M/XDR-TB). It was previously reported that azole drugs are active against M. tuberculosis. For that reason, the aims of this study were to determine the in vitro activity of azole drugs, imidazole (clotrimazole, CLO and econazole, ECO) and nitroimidazole (metronidazole, MZ and ipronidazole, IPZ), against a collection of MDR M. tuberculosis clinical isolates; and to analyze their potential use in both the LTB and the active forms of M/XDR-TB treatments. METHODS: A total of 55 MDR M. tuberculosis isolates and H37Rv were included. MZ and IPZ activity against M. tuberculosis isolates were tested using anaerobic culture conditions. The activity of ECO and CLO was measured by the minimal inhibitory concentration (MIC) using a microdilution colorimetric method. RESULTS: MZ and IPZ showed bacteriostatic activity against M. tuberculosis strains. MIC50 and MIC90 to ECO was 4.0µg/ml, while MIC50 to CLO was 4.0µg/ml and MIC90 was 8.0µg/ml respectively. CONCLUSION: All azole compounds tested in the study showed inhibitory activity against MDR M. tuberculosis clinical isolates.


Subject(s)
Antitubercular Agents , Azoles , Mycobacterium tuberculosis , Antitubercular Agents/pharmacology , Azoles/pharmacology , Humans , Microbial Sensitivity Tests , Mycobacterium tuberculosis/drug effects , Tuberculosis , Tuberculosis, Multidrug-Resistant/drug therapy
7.
PLoS One ; 12(1): e0169422, 2017.
Article in English | MEDLINE | ID: mdl-28046078

ABSTRACT

Ruminants are the primary reservoir of Shiga-toxin producing Escherichia coli (STEC) O157:H7 and the main source of infection for humans. The aim of this study was to assess the immunogenic properties of a candidate vaccine consisting on the recombinant proteins of E. coli O157:H7 IntiminC280, the carboxy-terminal fraction of Intimin γ, EspB and the fusion protein between the B subunit of Stx2 and Brucella Lumazine Synthase (BLS)(BLS-Stx2B), in Holstein Fresian calves.To accomplish this goal we vaccinated calves with two doses of different vaccine formulations: 2 antigens (IntiminC280, EspB), 3 antigens (IntiminC280, EspB, BLS-Stx2B), BLS-Stx2B alone and a control non-vaccinated group. All antigens were expressed as recombinant proteins in E. coli. Specific IgG titres increased in vaccinated calves and the inclusion of BLS-Stx2B in the formulation seems to have a stimulatory effect on the humoral response to IntiminC280 and EspB after the booster. The neutralizing activity of antibodies against these two antigens was assessed in Red Blood Cell lysis assays and adherence to Hep-2 cells as a correlate of T3SS activity. Both sera from animals vaccinated with 2 or 3 antigens inhibited both virulence properties. Serological response to Stx2 was observed in animals vaccinated only with BLS-Stx2B and with 3 antigens and neutralization of Stx2 cytotoxicity was also observed in both groups. In conclusion, immunization of calves with BLS-Stx2B, IntiminC280 and EspB elicited a potent humoral response able to neutralize Shiga toxin 2 cytotoxity and the T3SS virulence properties in vitro. These results suggest that this formulation is a good candidate vaccine to reduce STEC shedding in cattle and needs to be further assessed in vivo.


Subject(s)
Cattle Diseases/immunology , Cattle/immunology , Escherichia coli Infections/veterinary , Escherichia coli Vaccines/immunology , Shiga Toxin 2/immunology , Type III Secretion Systems , Adhesins, Bacterial/metabolism , Animals , Antibodies, Bacterial/blood , Bacterial Outer Membrane Proteins/metabolism , Bacterial Shedding , Cattle Diseases/microbiology , Cell Adhesion , Chlorocebus aethiops , Erythrocytes/microbiology , Escherichia coli Infections/immunology , Escherichia coli O157/pathogenicity , Escherichia coli Proteins/metabolism , Immunity, Humoral , Immunoglobulin G/blood , Male , Recombinant Proteins/immunology , Vero Cells , Virulence
8.
Microbiol Immunol ; 60(8): 552-60, 2016 Aug.
Article in English | MEDLINE | ID: mdl-27427512

ABSTRACT

Mycobacterium tuberculosis and Mycobacterium bovis are responsible for tuberculosis in humans and animals, respectively. Both species are closely related and belong to the Mycobacterium tuberculosis complex (MTC). M. tuberculosis is the most ancient species from which M. bovis and other members of the MTC evolved. The genome of M. bovis is over >99.95% identical to that of M. tuberculosis but with seven deletions ranging in size from 1 to 12.7 kb. In addition, 1200 single nucleotide mutations in coding regions distinguish M. bovis from M. tuberculosis. In the present study, we assessed 75 M. tuberculosis genomes and 23 M. bovis genomes to identify non-synonymous mutations in 202 coding sequences of regulatory genes between both species. We identified species-specific variants in 20 regulatory proteins and confirmed differential expression of hypoxia-related genes between M. bovis and M. tuberculosis.


Subject(s)
Bacterial Proteins/genetics , Mycobacterium bovis/genetics , Mycobacterium tuberculosis/genetics , Polymorphism, Genetic , Animals , Cattle , Computational Biology/methods , Evolution, Molecular , Gene Expression Regulation, Bacterial , Genes, Bacterial , Genome, Bacterial , Humans , Mutation , Transcription Factors/genetics , Transcription, Genetic , Tuberculosis/microbiology , Tuberculosis, Bovine/microbiology
9.
Tuberculosis (Edinb) ; 94(6): 672-7, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25306497

ABSTRACT

There has been an on-going debate on whether the development of drug resistance in Mycobacterium tuberculosis reduces its relative fitness and its ability to cause disease. The aim of this study was to explore this relationship. For this purpose, we evaluated the in vitro growth of clinical isolates and the transmission of the strains within the patients' households. Clinical and epidemiological data from patients in households, drug-susceptibility and genetic patterns of the isolates were collected. BACTEC MGIT 960™ system with the Epicenter™ software was used to perform fitness experiments and calculate the relative fitness (RF) comparing with the H73Rv reference strain. From 39 households, 124 patients and 388 contacts were included. Concerning transmission, 20 Multi drug-resistant (MDR) and 16 drug sensitive (DS) index cases generated 23 and 28 secondary cases, respectively. An average RF drop of 16.7% was found for MDR strains, but only mutations in rpoB codons 531 were associated with reduced fitness. When the strains were transmitted, their RF tended to decrease, and strains with low RF were less frequently transmitted. Within the limitations of this study, the results showed that the decrease in RF was associated to a limited transmission among the households' contacts.


Subject(s)
Family Health/statistics & numerical data , Mycobacterium tuberculosis/drug effects , Tuberculosis, Multidrug-Resistant/microbiology , Adolescent , Adult , Aged , Antitubercular Agents/pharmacology , Child , Child, Preschool , Drug Resistance, Multiple, Bacterial/genetics , Female , Humans , Infant , Male , Microbial Sensitivity Tests/methods , Middle Aged , Mutation , Mycobacterium tuberculosis/genetics , Mycobacterium tuberculosis/growth & development , Mycobacterium tuberculosis/pathogenicity , Tuberculosis, Multidrug-Resistant/transmission , Virulence/genetics , Young Adult
10.
Biomed Res Int ; 2014: 951978, 2014.
Article in English | MEDLINE | ID: mdl-24588000

ABSTRACT

A Mycobacterium bovis knockout in p27-p55 operon was tested as an antituberculosis experimental vaccine in animal models. The mutant MbΔp27-p55 was significantly more attenuated in nude mice than its parental strain but more virulent than BCG Pasteur. Challenge experiments in mice and guinea pigs using M. bovis or M. tuberculosis strains showed similar protection conferred by MbΔp27-p55 mutant than BCG in terms of pathology and bacterial loads in spleen but lower protection than BCG in lungs. When tested in cattle, MbΔp27-p55 did not induce IL-2 expression and induced a very low production of IFNγ, suggesting that the lack of P27/P55 reduces the capacity of M. bovis of triggering an adequate Th1 response.


Subject(s)
Bacterial Proteins/genetics , Lipoproteins/genetics , Membrane Transport Proteins/genetics , Mycobacterium bovis/genetics , Tuberculosis/immunology , Animals , BCG Vaccine/therapeutic use , Cattle , Guinea Pigs , Humans , Interleukin-2/immunology , Interleukin-2/metabolism , Mice , Models, Animal , Mycobacterium bovis/pathogenicity , Mycobacterium tuberculosis/genetics , Mycobacterium tuberculosis/pathogenicity , Operon/genetics , Operon/immunology , Tuberculosis/genetics , Tuberculosis/prevention & control
11.
Virulence ; 4(1): 3-66, 2013 Jan 01.
Article in English | MEDLINE | ID: mdl-23076359

ABSTRACT

The Mycobacterium tuberculosis complex (MTBC) consists of closely related species that cause tuberculosis in both humans and animals. This illness, still today, remains to be one of the leading causes of morbidity and mortality throughout the world. The mycobacteria enter the host by air, and, once in the lungs, are phagocytated by macrophages. This may lead to the rapid elimination of the bacillus or to the triggering of an active tuberculosis infection. A large number of different virulence factors have evolved in MTBC members as a response to the host immune reaction. The aim of this review is to describe the bacterial genes/proteins that are essential for the virulence of MTBC species, and that have been demonstrated in an in vivo model of infection. Knowledge of MTBC virulence factors is essential for the development of new vaccines and drugs to help manage the disease toward an increasingly more tuberculosis-free world.


Subject(s)
Mycobacterium tuberculosis/pathogenicity , Tuberculosis/microbiology , Tuberculosis/veterinary , Virulence Factors , Animals , Host-Pathogen Interactions , Humans , Immune Evasion
12.
Rev Argent Microbiol ; 44(4): 283-9, 2012.
Article in English | MEDLINE | ID: mdl-23267627

ABSTRACT

Tuberculosis (tB) and multidrug and extensively drug-resistant (dR) tB are important public health problems that are spreading worldwide. The aims of this study were to determine the sensitivity and specificity of the genotype® mtBdRplus assay from smear-positive clinical specimens and isolates and to explore its possible application in routine work. Clinical samples were previously decontaminated using naoH-n-acetyl-l-cystein or naoH-Clna hypertonic solution for Ziehl-neelsen staining and cultures. The leftover sediments of smear-positive samples were stored at -20 °C, 70 of which were selected to be included in this study according to their dR profile. thirty dR Mycobacterium tuberculosis isolates were also assessed. Sequencing was used as gold standard to detect mutations conferring isoniazid (InH) and rifampicin (RIF) resistance. Valid results were obtained in 94.0 % of the samples and 85.5 % (53/62) of the InH-R samples were properly identified. mutations in the katGS315t gene and inhA C-15t gene promoter region were present in 59.7 % (37/62) and 25.8 % (16/62) of the InH-R samples, respectively. the system could also identify 97.7 % (41/42) of the RIF-R samples; the mutations found were rpoBS531l (66.7 %, 28/42), d516V (19.0 %, 8/42), H526Y and S531p/W (4.8 %, 2/42 each one), and S522l/Q (2.4 %, 1/42). a 98.8 % concordance between the genotype assay and sequencing was obtained. genotype® mtBdRplus has demonstrated to be easy to implement and to perform in clinical laboratories and useful for a rapid detection of dR M. tuberculosis from decontaminated sputa and clinical isolates. Therefore, this assay could be applied as a rapid tool to predict InH-R and/or RIF-R in dR risk cases.


Subject(s)
Mycobacterium tuberculosis/isolation & purification , Tuberculosis, Multidrug-Resistant/diagnosis , Tuberculosis, Multidrug-Resistant/microbiology , Argentina , Bacteriological Techniques , Humans , Molecular Diagnostic Techniques , Retrospective Studies , Sensitivity and Specificity
13.
Microbes Infect ; 14(7-8): 590-9, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22353253

ABSTRACT

The Mycobacterium smegmatis genome contains six operons designated mce (mammalian cell entry). These operons, which encode membrane and exported proteins, are highly conserved in pathogenic and non-pathogenic mycobacteria. Although the function of the Mce protein family has not yet been established in Mycobacterium smegmatis, the requirement of the mce4 operon for cholesterol utilization and uptake by Mycobacterium tuberculosis has recently been demonstrated. In this study, we report the construction of an M. smegmatis knock-out mutant deficient in the expression of all six mce operons. The consequences of these mutations were studied by analyzing physiological parameters and phenotypic traits. Differences in colony morphology, biofilm formation and aggregation in liquid cultures were observed, indicating that mce operons of M. smegmatis are implicated in the maintenance of the surface properties of the cell. Importantly, the mutant strain showed reduced cholesterol uptake when compared to the parental strain. Further cholesterol uptake studies using single mce mutant strains showed that the mutation of operon mce4 was reponsible for the cholesterol uptake failure detected in the sextuple mce mutant. This finding demonstrates that mce4operon is involved in cholesterol transport in M. smegmatis.


Subject(s)
Cholesterol/pharmacokinetics , Genes, Bacterial , Mycobacterium smegmatis/genetics , Mycobacterium smegmatis/metabolism , Operon/genetics , Sequence Deletion , Virulence/genetics , Gene Expression Regulation, Bacterial , Gene Knockout Techniques , Mutation , Mycobacterium smegmatis/pathogenicity , Mycobacterium tuberculosis/genetics , Mycobacterium tuberculosis/metabolism
14.
Rev. argent. microbiol ; Rev. argent. microbiol;43(4): 294-310, dic. 2011. ilus, tab
Article in Spanish | LILACS | ID: lil-634707

ABSTRACT

Bacillus anthracis es un bacilo gram positivo del grupo Bacillus cereus, que posee un genoma extremadamente monomórfco y comparte gran similitud fsiológica y de estructura genética con B. cereus y Bacillus thuringiensis. En este artículo se describen nuevos métodos moleculares para la identifcación y tipifcación de B. anthracis, basados en repeticiones en tándem de número variable o en diferencias genéticas detectadas por secuenciación, desarrollados en los últimos años. Los aspectos moleculares de los factores de virulencia tradicionales, cápsula, antígeno protector, factor letal y factor edema se describen en profundidad, junto con factores de virulencia recientemente propuestos, como los sideróforos, petrobactina y bacilibactina, la adhesina de la capa S y la lipoproteína MntA. También se detalla la organización molecular de los megaplásmidos pXO1 y pXO2, incluyendo la isla de patogenicidad de pXO1. El esqueleto genético de estos plásmidos se ha encontrado en otras especies relacionadas, probablemente debido a eventos de transferencia lateral. Finalmente, se presentan los dos receptores celulares del antígeno protector, ANTXR1/TEM8 y ANTXR2/CMG2, esenciales en la interacción del patógeno con el hospedador. Los estudios moleculares realizados en los últimos años han permitido aumentar enormemente el conocimiento de los diferentes aspectos de este microorganismo y su relación con el hospedador, pero a la vez han abierto nuevos interrogantes sobre este notorio patógeno.


Bacillus anthracis, a gram-positive rod belonging to the Bacillus cereus group, has an extremely monomorphic genome, and presents high structural and physiological similarity with B. cereus and Bacillus thuringiensis. In this work, the new molecular methods for the identifcation and typing of B. anthracis developed in the last years, based on variable number tandem repeats or on genetic differences detected through sequencing, are described. The molecular aspects of traditional virulence factors: capsule, protective antigen, lethal factor and edema factor are described in depth, together with virulence factors recently proposed, such as the siderophores petrobactin and bacillibactin, the S-layer adhesin and the MntA lipoprotein. It is detailed the molecular organization of megaplasmids pXO1 and pXO2, including the pathogenicity island of pXO1. The genetic skeleton of these plasmids has been observed in related species, and this could be attributed to lateral gene transfer. Finally, the two anthrax toxin protective antigen receptors, ANTXR1/TEM8 and ANTXR2/CMG2, essential for the interaction of the pathogen with the host, are presented. The molecular studies performed in recent years have greatly increased knowledge in different aspects of this microorganism and its relationship with the host, but at the same time they have raised new questions about this noted pathogen.


Subject(s)
Animals , Humans , Anthrax/microbiology , Bacillus anthracis/physiology , Anthrax/epidemiology , Anthrax/veterinary , Antigens, Bacterial/immunology , Antigens, Bacterial/physiology , Bacterial Toxins , Bacterial Typing Techniques , Base Sequence , Bacillus anthracis/classification , Bacillus anthracis/genetics , Bacillus anthracis/pathogenicity , Bacillus/classification , Bacterial Capsules/physiology , DNA, Bacterial/genetics , Genomic Islands/physiology , Minisatellite Repeats , Molecular Sequence Data , Membrane Proteins/genetics , Membrane Proteins/physiology , Neoplasm Proteins/genetics , Neoplasm Proteins/physiology , Plasmids , Polymorphism, Single Nucleotide , Receptors, Cell Surface/genetics , Receptors, Cell Surface/physiology , Sequence Alignment , Sequence Homology, Nucleic Acid , Virulence/genetics , Virulence/physiology , Zoonoses
16.
BMC Infect Dis ; 11: 195, 2011 Jul 16.
Article in English | MEDLINE | ID: mdl-21762531

ABSTRACT

BACKGROUND: The P27-P55 (lprG-Rv1410c) operon is crucial for the survival of Mycobacterium tuberculosis, the causative agent of human tuberculosis, during infection in mice. P55 encodes an efflux pump that has been shown to provide Mycobacterium smegmatis and Mycobacterium bovis BCG with resistance to several drugs, while P27 encodes a mannosylated glycoprotein previously described as an antigen that modulates the immune response against mycobacteria. The objective of this study was to determine the individual contribution of the proteins encoded in the P27-P55 operon to the resistance to toxic compounds and to the cell wall integrity of M. tuberculosis. METHOD: In order to test the susceptibility of a mutant of M. tuberculosis H37Rv in the P27-P55 operon to malachite green, sodium dodecyl sulfate, ethidium bromide, and first-line antituberculosis drugs, this strain together with the wild type strain and a set of complemented strains were cultivated in the presence and in the absence of these drugs. In addition, the malachite green decolorization rate of each strain was obtained from decolorization curves of malachite green in PBS containing bacterial suspensions. RESULTS: The mutant strain decolorized malachite green faster than the wild type strain and was hypersensitive to both malachite green and ethidium bromide, and more susceptible to the first-line antituberculosis drugs: isoniazid and ethambutol. The pump inhibitor reserpine reversed M. tuberculosis resistance to ethidium bromide. These results suggest that P27-P55 functions through an efflux-pump like mechanism. In addition, deletion of the P27-P55 operon made M. tuberculosis susceptible to sodium dodecyl sulfate, suggesting that the lack of both proteins causes alterations in the cell wall permeability of the bacterium. Importantly, both P27 and P55 are required to restore the wild type phenotypes in the mutant. CONCLUSIONS: The results clearly indicate that P27 and P55 are functionally connected in processes that involve the preservation of the cell wall and the transport of toxic compounds away from the cells.


Subject(s)
Bacterial Proteins/genetics , Lipoproteins/genetics , Membrane Transport Proteins/genetics , Mycobacterium tuberculosis/genetics , Operon , Anti-Infective Agents/pharmacology , Blotting, Western , Cell Membrane/chemistry , Cell Survival/drug effects , Cell Wall/chemistry , Drug Resistance, Microbial , Electrophoresis, Polyacrylamide Gel , Ethambutol/pharmacology , Ethidium/pharmacology , Isoniazid/pharmacology , Microbial Sensitivity Tests , Mutation , Mycobacterium tuberculosis/drug effects , Rosaniline Dyes/pharmacology , Sodium Dodecyl Sulfate
18.
Rev Argent Microbiol ; 43(4): 294-310, 2011.
Article in Spanish | MEDLINE | ID: mdl-22274828

ABSTRACT

Bacillus anthracis, a gram-positive rod belonging to the Bacillus cereus group, has an extremely monomorphic genome, and presents high structural and physiological similarity with B. cereus and Bacillus thuringiensis. In this work, the new molecular methods for the identification and typing of B. anthracis developed in the last years, based on variable number tandem repeats or on genetic differences detected through sequencing, are described. The molecular aspects of traditional virulence factors: capsule, protective antigen, lethal factor and edema factor are described in depth, together with virulence factors recently proposed, such as the siderophores petrobactin and bacillibactin, the S-layer adhesin and the MntA lipoprotein. It is detailed the molecular organization of megaplasmids pXO1 and pXO2, including the pathogenicity island of pXO1. The genetic skeleton of these plasmids has been observed in related species, and this could be attributed to lateral gene transfer. Finally, the two anthrax toxin protective antigen receptors, ANTXR1/TEM8 and ANTXR2/CMG2, essential for the interaction of the pathogen with the host, are presented. The molecular studies performed in recent years have greatly increased knowledge in different aspects of this microorganism and its relationship with the host, but at the same time they have raised new questions about this noted pathogen.


Subject(s)
Anthrax/microbiology , Bacillus anthracis/physiology , Animals , Anthrax/epidemiology , Anthrax/veterinary , Antigens, Bacterial/immunology , Antigens, Bacterial/physiology , Bacillus/classification , Bacillus anthracis/classification , Bacillus anthracis/genetics , Bacillus anthracis/pathogenicity , Bacterial Capsules/physiology , Bacterial Toxins , Bacterial Typing Techniques , Base Sequence , DNA, Bacterial/genetics , Genomic Islands/physiology , Humans , Membrane Proteins/genetics , Membrane Proteins/physiology , Microfilament Proteins , Minisatellite Repeats , Molecular Sequence Data , Neoplasm Proteins/genetics , Neoplasm Proteins/physiology , Plasmids , Polymorphism, Single Nucleotide , Receptors, Cell Surface/genetics , Receptors, Cell Surface/physiology , Receptors, Peptide , Sequence Alignment , Sequence Homology, Nucleic Acid , Virulence/genetics , Virulence/physiology , Zoonoses
19.
Microbiol Immunol ; 53(8): 460-7, 2009 Aug.
Article in English | MEDLINE | ID: mdl-19659930

ABSTRACT

A number of studies have determined the contribution of Th1 and Th2 responses to the protective immunity and pathology of Mycobacterium bovis infection. However, much of that information is derived from experimentally infecting cattle with M. bovis and few data from naturally infected animals are available. The aim of this study was to characterize the immunological profile towards M. bovis antigens of naturally infected cattle by measurement of cytokine mRNA expression in PBMC, and to determine which lymphocyte subsets are involved in recall responses of PBMC from M. bovis infected cattle to M. bovis antigens. Consistent with data from cattle experimentally infected with M. bovis, naturally infected animals were found to display a Th1 cytokine profile in response to M. bovis PPDB stimulation. Production of IFN-gamma mRNA by PBMC after PPDB stimulation statistically distinguishes between infected and healthy herds, suggesting that this molecule is usable as an M. bovis-infection marker. As happens in experimentally infected cows, CD4, CD8 and gammadeltaTCR cells from a herd naturally infected with M. bovis are the predominant T cell subsets expanded in response to PPDB.


Subject(s)
Antigens, Bacterial/immunology , Mycobacterium bovis/immunology , Tuberculosis, Bovine/immunology , Animals , Antigens, Bacterial/genetics , Cattle , Cells, Cultured , Cytokines/genetics , Cytokines/immunology , Gene Expression , Leukocytes, Mononuclear/immunology , Leukocytes, Mononuclear/microbiology , Mycobacterium bovis/genetics , T-Lymphocyte Subsets/immunology , Tuberculosis, Bovine/genetics , Tuberculosis, Bovine/microbiology
20.
Microbes Infect ; 11(12): 956-63, 2009 Oct.
Article in English | MEDLINE | ID: mdl-19591956

ABSTRACT

The identification of factors involved in the interaction of Mycobacterium bovis with the hosts will lead to new strategies to control bovine tuberculosis. In this study we compared the transcriptional profile of an attenuated M. bovis strain and a virulent M. bovis strain as a means to elucidate the molecular basis for their differential phenotype. Microarray and RT-qPCR results demonstrated that the expression of mce4D, Mb2607/Mb2608 and Mb3706c were up-regulated in the virulent strain whereas alkB, Mb3277c and Mb1077c were expressed at higher levels in the attenuated strain. These differential expression profiles were confirmed for Mb2607/Mb2608, mce4D, Mb1077c, alkB and Mb3277c during the replication of bacteria inside macrophages.


Subject(s)
Gene Expression Profiling , Gene Expression Regulation, Bacterial , Mycobacterium bovis/genetics , Mycobacterium bovis/pathogenicity , Animals , Cattle , Cells, Cultured , Macrophages/microbiology , Mice , Mycobacterium bovis/isolation & purification , Oligonucleotide Array Sequence Analysis , Reverse Transcriptase Polymerase Chain Reaction , Sus scrofa
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