RESUMO
Chromobacterium violaceum is a ubiquitous environmental bacterium that causes sporadic life-threatening infections in humans. How C. violaceum acquires zinc to colonize environmental and host niches is unknown. In this work, we demonstrated that C. violaceum employs the zinc uptake system ZnuABC to overcome zinc limitation in the host, ensuring the zinc supply for several physiological demands. Our data indicated that the C. violaceum ZnuABC transporter is encoded in a zur-CV_RS15045-CV_RS15040-znuCBA operon. This operon was repressed by the zinc uptake regulator Zur and derepressed in the presence of the host protein calprotectin (CP) and the synthetic metal chelator EDTA. A ΔznuCBA mutant strain showed impaired growth under these zinc-chelated conditions. Moreover, the deletion of znuCBA provoked reductions in violacein production, swimming motility, biofilm formation, and bacterial competition. Remarkably, the ΔznuCBA mutant strain was highly attenuated for virulence in an in vivo mouse infection model and showed low capacities to colonize the liver, grow in the presence of CP, and resist neutrophil killing. Overall, our findings demonstrate that ZnuABC is essential for C. violaceum virulence, contributing to subversion of zinc-based host nutritional immunity.
Assuntos
Proteínas de Transporte/fisiologia , Chromobacterium/patogenicidade , Zinco/metabolismo , Biofilmes , Proteínas de Transporte/genética , Chromobacterium/fisiologia , Complexo Antígeno L1 Leucocitário/fisiologia , Neutrófilos/imunologia , Óperon , VirulênciaRESUMO
Iron is a highly reactive metal that participates in several processes in prokaryotic and eukaryotic cells. Hosts and pathogens compete for iron in the context of infection. Chromobacterium violaceum, an environmental Gram-negative bacterial pathogen, relies on siderophores to overcome iron limitation in the host. In this work, we studied the role of the ferric uptake regulator Fur in the physiology and virulence of C. violaceum A Δfur mutant strain showed decreased growth and fitness under regular in vitro growth conditions and presented high sensitivity to iron and oxidative stresses. Furthermore, the absence of fur caused derepression of siderophore production and reduction in swimming motility and biofilm formation. Consistent with these results, the C. violaceum Δfur mutant was highly attenuated for virulence and liver colonization in mice. In contrast, a manganese-selected spontaneous fur mutant showed only siderophore overproduction and sensitivity to oxidative stress, indicating that Fur remained partially functional in this strain. We found that mutations in genes related to siderophore biosynthesis and a putative CRISPR-Cas locus rescued the Δfur mutant growth defects, indicating that multiple Fur-regulated processes contribute to maintaining bacterial cell fitness. Overall, our data indicated that Fur is conditionally essential in C. violaceum mainly by protecting cells from iron overload and oxidative damage. The requirement of Fur for virulence highlights the importance of iron in the pathogenesis of C. violaceumIMPORTANCE Maintenance of iron homeostasis, i.e., avoiding both deficiency and toxicity of this metal, is vital to bacteria and their hosts. Iron sequestration by host proteins is a crucial strategy to combat bacterial infections. In bacteria, the ferric uptake regulator Fur coordinates the expression of several iron-related genes. Sometimes, Fur can also regulate several other processes. In this work, we performed an in-depth phenotypic characterization of fur mutants in the human opportunistic pathogen Chromobacterium violaceum We determined that fur is a conditionally essential gene necessary for proper growth under regular conditions and is fully required for survival under iron and oxidative stresses. Fur also controlled several virulence-associated traits, such as swimming motility, biofilm formation, and siderophore production. Consistent with these results, a C. violaceumfur null mutant showed attenuation of virulence. Therefore, our data established Fur as a major player required for C. violaceum to manage iron, including during infection in the host.
Assuntos
Proteínas de Bactérias/genética , Chromobacterium/fisiologia , Chromobacterium/patogenicidade , Ferro/toxicidade , Estresse Oxidativo , Proteínas Repressoras/genética , Sideróforos/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas Repressoras/metabolismo , VirulênciaRESUMO
Bacteria use siderophores to scavenge iron from environmental or host sources. The iron acquisition systems of Chromobacterium violaceum, a ubiquitous environmental bacterium that can cause infections in humans, are still unknown. In this work, we demonstrated that C. violaceum produces putative distinct endogenous siderophores, here named chromobactin and viobactin, and showed that they are each required for iron uptake and virulence. An in silico analysis in the genome of C. violaceum revealed that genes related to synthesis and uptake of chromobactin (cba) and viobactin (vba) are located within two secondary-metabolite biosynthetic gene clusters. Using a combination of gene deletions and siderophore detection assays, we revealed that chromobactin and viobactin are catecholate siderophores synthesized from the common precursor 2,3-dihydroxybenzoate (2,3-DHB) on two nonribosomal peptide synthetase (NRPS) enzymes (CbaF and VbaF) and taken up by two TonB-dependent receptors (CbuA and VbuA). Infection assays in mice revealed that both the synthesis and the uptake of chromobactin or viobactin are required for the virulence of C. violaceum, since only the mutant strains that do not produce any siderophores or are unable to take up both of them were attenuated for virulence. In addition, the mutant strain unable to take up both siderophores showed a pronounced attenuation of virulence in vivo and reduced neutrophil extracellular trap (NET) formation in in vitro assays, suggesting that extracellularly accumulated siderophores modulate the host immune response. Overall, our results revealed that C. violaceum uses distinct endogenous siderophores for iron uptake and its establishment in the host.
Assuntos
Chromobacterium/genética , Chromobacterium/metabolismo , Ferro/metabolismo , Sideróforos/genética , Sideróforos/metabolismo , Animais , Transporte Biológico/fisiologia , Chromobacterium/patogenicidade , Armadilhas Extracelulares/metabolismo , Feminino , Hidroxibenzoatos/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Família Multigênica/genética , Neutrófilos/metabolismo , Peptídeo Sintases/metabolismoRESUMO
Seed oils from oleaginous plants are rich in fatty acids (FAs) that play important roles in the health of the consumers. Recent studies indicate that FA also can play an important role in communication and regulation of virulence in bacteria. Nevertheless, evidence demonstrating protection against bacterial infections mediated by their quorum sensing inhibition (QSI) activity is scarce. In this study, sunflower, chia, and amaranth oils, were assayed for their QSI capacity by inhibiting violacein production and alkaline exoprotease activity of Chromobacterium violaceum. In vitro assays revealed that the oils exhibited QSI activities, whereas in vivo they delayed death of mice inoculated intraperitoneally with the bacterium. Gas chromatography coupled with mass spectrometry analysis of the oils indicated the presence of saturated FA (SAFA) and unsaturated FA as main components. Through a structure-activity relationship study of free FAs, bactericidal effect was identified mainly for polyunsaturated FAs, whereas QSI activity was restricted to SAFA of chains 12-18 carbon atoms in length. These data correlate with a possible interaction suggested by molecular docking analysis of lauric, myristic, and stearic acids with the CviR protein. Our study highlights the antiquorum sensing potential of SAFA, which may be future antivirulence therapeutic agents for the treatment of bacterial infections.
Assuntos
Antibacterianos/farmacologia , Chromobacterium/efeitos dos fármacos , Ácidos Graxos/farmacologia , Magnoliopsida/química , Óleos de Plantas/farmacologia , Percepção de Quorum/efeitos dos fármacos , Sementes/química , Amaranthus/química , Animais , Antibacterianos/química , Antibacterianos/uso terapêutico , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/microbiologia , Chromobacterium/metabolismo , Chromobacterium/patogenicidade , Exopeptidases/metabolismo , Ácidos Graxos/química , Ácidos Graxos/uso terapêutico , Ácidos Graxos Insaturados/química , Ácidos Graxos Insaturados/farmacologia , Ácidos Graxos Insaturados/uso terapêutico , Cromatografia Gasosa-Espectrometria de Massas , Helianthus/química , Indóis/metabolismo , Camundongos , Simulação de Acoplamento Molecular , Óleos de Plantas/química , Óleos de Plantas/uso terapêutico , Salvia/química , Relação Estrutura-Atividade , Fatores de Virulência/metabolismoRESUMO
Report of Chromobacterium violaceum isolation from blood culture. Identification by MALDI-TOF mass spectrometry. Relevant report due to the site affected, infection severity, and importance of correct and rapid identification for a successful treatment and lower risk of morbidity and mortality. (AU)
Assuntos
Humanos , Masculino , Pessoa de Meia-Idade , Chromobacterium/patogenicidade , Sepse/diagnóstico , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Hemocultura/métodosRESUMO
A major pathway for the detoxification of organic hydroperoxides, such as cumene hydroperoxide (CHP), involves the MarR family transcriptional regulator OhrR and the peroxidase OhrA. However, the effect of these peroxides on the global transcriptome and the contribution of the OhrA/OhrR system to bacterial virulence remain poorly explored. Here, we analyzed the transcriptome profiles of Chromobacterium violaceum exposed to CHP and after the deletion of ohrR, and we show that OhrR controls the virulence of this human opportunistic pathogen. DNA microarray and Northern blot analyses of CHP-treated cells revealed the upregulation of genes related to the detoxification of peroxides (antioxidant enzymes and thiol-reducing systems), the degradation of the aromatic moiety of CHP (oxygenases), and protection against other secondary stresses (DNA repair, heat shock, iron limitation, and nitrogen starvation responses). Furthermore, we identified two upregulated genes (ohrA and a putative diguanylate cyclase with a GGDEF domain for cyclic di-GMP [c-di-GMP] synthesis) and three downregulated genes (hemolysin, chitinase, and collagenase) in the ohrR mutant by transcriptome analysis. Importantly, we show that OhrR directly repressed the expression of the putative diguanylate cyclase. Using a mouse infection model, we demonstrate that the ohrR mutant was attenuated for virulence and showed a decreased bacterial burden in the liver. Moreover, an ohrR-diguanylate cyclase double mutant displayed the same virulence as the wild-type strain. In conclusion, we have defined the transcriptional response to CHP, identified potential virulence factors such as diguanylate cyclase as members of the OhrR regulon, and shown that C. violaceum uses the transcriptional regulator OhrR to modulate its virulence.
Assuntos
Proteínas de Bactérias/metabolismo , Derivados de Benzeno/metabolismo , Derivados de Benzeno/farmacologia , Chromobacterium/genética , Chromobacterium/patogenicidade , Proteínas Repressoras/metabolismo , Transcrição Gênica , Animais , Carga Bacteriana , Proteínas de Bactérias/genética , Quitinases/genética , Colagenases/genética , Proteínas de Escherichia coli/genética , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Infecções por Bactérias Gram-Negativas/microbiologia , Proteínas Hemolisinas , Humanos , Peróxido de Hidrogênio , Fígado/microbiologia , Camundongos , Oxigenases/metabolismo , Peroxidases/metabolismo , Fósforo-Oxigênio Liases/genética , Regiões Promotoras Genéticas , Proteínas Repressoras/genética , Estresse Fisiológico , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Virulência , Fatores de Virulência/genéticaRESUMO
Chromobacterium violaceum is a free-living Gram-negative bacillus usually found in the water and soil in tropical regions, which causes infections in humans. Chromobacteriosis is characterized by rapid dissemination and high mortality. The aim of this study was to detect the genetic variability among C. violaceum type strain ATCC 12472, and seven isolates from the environment and one from a pulmonary secretion from a chromobacteriosis patient from Ilhéus, Bahia. The molecular characterization of all samples was performed by polymerase chain reaction (PCR) sequencing and 16S rDNA analysis. Primers specific for two ATCC 12472 pathogenicity genes, hilA and yscD, as well as random amplified polymorphic DNA (RAPD), were used for PCR amplification and comparative sequencing of the products. For a more specific approach, the PCR products of 16S rDNA were digested with restriction enzymes. Seven of the samples, including type-strain ATCC 12472, were amplified by the hilA primers; these were subsequently sequenced. Gene yscD was amplified only in type-strain ATCC 12472. MspI and AluI digestion revealed 16S rDNA polymorphisms. This data allowed the generation of a dendogram for each analysis. The isolates of C. violaceum have variability in random genomic regions demonstrated by RAPD. Also, these isolates have variability in pathogenicity genes, as demonstrated by sequencing and restriction enzyme digestion.
Assuntos
Chromobacterium/genética , Pulmão/microbiologia , Polimorfismo Genético , Microbiologia do Solo , Microbiologia da Água , Proteínas de Bactérias/genética , Chromobacterium/isolamento & purificação , Chromobacterium/patogenicidade , Cisteína Endopeptidases/genética , Humanos , RNA Ribossômico 16S/genética , Virulência/genéticaRESUMO
Chromobacterium violaceum is a rare pathogen that can potentially cause fatal infections in humans. An 8-year-old child from Natal, northeast of Brazil, presented history of fever, sore throat, and abdominal pain, during 5 days before admission, and died 4 hours after hospitalization. Chromobacterium violaceum was isolated from oropharynx scrapings and was resistant to ampicillin, cefotaxime, cefalotin, ceftazidime, and ceftriaxone...
Chromobacterium violaceum é um patógeno raro que potencialmente pode causar infecções fatais em humanos. Relatamos o caso de uma criança de 8 anos de idade, moradora da cidade de Natal, nordeste do Brasil, que apresentou história de febre, dor na garganta e no abdome durante os cinco dias anteriores à internação, e veio a falecer após 4 horas de hospitalização. A bactéria Chromobacterium violaceum foi isolada da orofaringe e apresentou resistência a ampicilina, cefotaxima, cefalotina, ceftazidima e ceftriaxona...
Assuntos
Humanos , Feminino , Criança , Resistência a Ampicilina , Chromobacterium/patogenicidade , Farmacorresistência Bacteriana , Cefotaxima , Ceftriaxona , Cefalotina , Evolução FatalRESUMO
BACKGROUND AND AIMS: Quorum sensing (QS) is a process of bacterial cell-cell communication that controls a large number of systems affecting pathogenicity. Interrupting this communication system can provide nonvirulent pathogenic bacteria. The aim of this study was to evaluate the anti-quorum sensing (anti-QS) potential of an anacardic acids mixture isolated from Amphipterygium adstringens, a medicinal plant known as "cuachalalate", to prevent the onset of bacterial infections as an alternate to antibiotics. METHODS: Initially we investigated the anti-QS activity of A. adstringens hexane extract (HE) by the inhibition of violacein production in Chromobacterium violaceum. From the active HE, an anacardic acid mixture (AAM) was obtained. The anti-quorum sensing activity of AAM was investigated by the rhamnolipid and pyocyanin production constraint as well as decrease of elastase activity, all being quorum sensing-controlled virulence factors expressed in the pathogenic bacteria Pseudomonas aeruginosa. RESULTS: HE induced a 91.6% of inhibition of the violecin production at 55 µg/mL concentration, whereas AAM showed 94% of inhibition at 166 µg/mL. In both cases, inhibition of violacein production did not affect the viability of the bacterium. AAM inhibited pyocyanin (86% at 200 µg/mL) and rhamnolipid (91% at 500 µg/mL) production in a dose/response form and decrease the elastase (75% at 500 µg/mL) activity in P. aeruginosa without affecting its development. CONCLUSIONS: Because an anacardic acids mixture isolated from A. adstringens demonstrated anti-QS, it could be further exploited for novel molecules to treat the emerging infections of antibiotic-resistant bacterial pathogens.
Assuntos
Ácidos Anacárdicos/farmacologia , Chromobacterium/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos dos fármacos , Percepção de Quorum/efeitos dos fármacos , Fatores de Virulência/antagonistas & inibidores , Anacardiaceae/química , Ácidos Anacárdicos/isolamento & purificação , Animais , Antibacterianos/farmacologia , Chromobacterium/crescimento & desenvolvimento , Chromobacterium/patogenicidade , Farmacorresistência Bacteriana , Glicolipídeos/antagonistas & inibidores , Glicolipídeos/metabolismo , Indóis/antagonistas & inibidores , Indóis/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/patogenicidade , Piocianina/antagonistas & inibidores , Piocianina/metabolismo , Fatores de Virulência/metabolismoRESUMO
Chromobacterium violaceum is a beta-proteobacterium with high biotechnological potential, found in tropical environments. This bacterium causes opportunistic infections in both humans and animals, that can spread throughout several tissues, quickly leading to the death of the host. Genomic studies identified potential mechanisms of pathogenicity but no further studies were done to confirm the expression of these systems. In this study 36 unique protein entries were identified in databank from a two-dimensional profile of C. violaceum secreted proteins. Chromobacterium violaceum exoproteomic preliminary studies confirmed the production of proteins identified as virulence factors (such as a collagenase, flagellum proteins, metallopeptidases, and toxins), allowing us to better understand its pathogenicity mechanisms. Biotechnologically interesting proteins (such as chitinase and chitosanase) were also identified among the secreted proteins, as well as proteins involved in the transport and capture of amino acids, carbohydrates, and oxidative stress protection. Overall, the secreted proteins identified provide us important insights on pathogenicity mechanisms, biotechnological potential, and environment adaptation of C. violaceum.
Assuntos
Proteínas de Bactérias/análise , Biotecnologia/métodos , Chromobacterium/química , Chromobacterium/patogenicidade , Microbiologia Industrial/métodos , Proteoma/análise , Animais , Chromobacterium/isolamento & purificação , Eletroforese em Gel Bidimensional , Microbiologia Ambiental , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/veterinária , Humanos , Espectrometria de Massas , Fatores de Virulência/análiseRESUMO
C. violaceum appeared as important bacterium in different applications and mainly these aspects are related to the production of violacein. This review discusses the last reports on biosynthetic pathways, production, genetic aspects, biological activities, pathological effects, antipathogenic screening through quorum sensing, environmental effects and the products of C. violaceum with industrial interest. An important discussion is on biological applications in medicine and as industrial products such as textile and in cosmetics.
Assuntos
Chromobacterium/metabolismo , Indóis/metabolismo , Vias Biossintéticas/genética , Chromobacterium/genética , Chromobacterium/patogenicidade , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/patologia , Humanos , Percepção de Quorum , VirulênciaRESUMO
Groups of genes that produce exopolysaccharide with a N-acetyl-D-glucosamine monomer are in the genome of several pathogenic bacteria. Chromobacterium violaceum, an opportunistic pathogen, has the operon hmsHFR-CV2940, whose proteins can synthesize such polysaccharide. In this work, multiple alignments among proteins from bacteria that synthesize such polysaccharide were used to verify the existence of amino acids that might be critical for pathogen activity. Three-dimensional models were generated for spatial visualization of these amino acid residues. The analysis carried out showed that the protein HmsR preserves the amino acids D135, D228, Q264 and R267, considered critical for the formation of biofilms and, furthermore, that these amino acids are close to each other. The protein HmsF of C. violaceum preserves the residues D86, D87, H156 and W115. It was also shown that these residues are also close to each other in their spatial arrangement. For the proteins HmsH and CV2940 there is evidence of conservation of the residues R104 and W94, respectively. Conservation and favorable spatial location of those critical amino acids that constitute the proteins of the operon indicates that they preserve the same enzymatic function in biofilm synthesis. This is an indicator that the operon hmsHFR-CV2940 is a possible target in C. violaceum pathogenicity.
Assuntos
Animais , Biofilmes/crescimento & desenvolvimento , Chromobacterium/patogenicidade , Acetilglucosaminidase , Biologia Computacional , PolissacarídeosRESUMO
Chromobacterium violaceum, a saprophyte bacterium found commonly in soil and water in tropical and subtropical climates, is a rare cause of severe, often fatal, human disease. We report 1 confirmed and 2 suspected cases of C. violaceum septicemia, with 2 fatalities, in siblings after recreational exposure in northeastern Brazil.
Assuntos
Infecções Bacterianas/fisiopatologia , Chromobacterium/patogenicidade , Microbiologia da Água , Adolescente , Infecções Bacterianas/etiologia , Brasil , Criança , Chromobacterium/isolamento & purificação , Evolução Fatal , Humanos , Masculino , IrmãosRESUMO
AIMS: To isolate and to characterize the diversity of Chromobacterium violaceum from the Brazilian Amazon region. METHODS AND RESULTS: Twenty-two isolates were obtained from the waters and banks of the river Negro, in the Brazilian Amazon. All isolates were able to grow in vitro at 44 degrees C and pH 4.0, but were adversely affected by temperatures below 15 degrees C, and unable to survive at 4 degrees C, properties that may be related to the adaptation to the ecosystem. The isolates were joined at a final level of similarity of only 13% in the rep-PCR analysis. The analysis of 16S rRNA genes resulted in three main groups clustered at a final level of similarity of 97% and only three isolates were clustered with the type strain. Similar data were obtained for the 23S rRNA gene. CONCLUSIONS: A high level of genetic diversity was verified with indications that the Brazilian isolates would fit into at least two new clusters besides C. violaceum species. SIGNIFICANCE AND IMPACT OF THE STUDY: The results show remarkable bacterial adaptability and genetic diversity of C. violaceum in the Amazon region.
Assuntos
Chromobacterium/isolamento & purificação , Rios/microbiologia , Microbiologia da Água , Brasil , Chromobacterium/genética , Chromobacterium/patogenicidade , Dados de Sequência Molecular , Família Multigênica , Reação em Cadeia da Polimerase , Polimorfismo Genético , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , RNA Ribossômico 23S/genéticaRESUMO
Chromobacterium violaceum is a versatile, Gram-negative beta-protebacterium that grows in a variety of ecosystems in tropical and subtropical areas, such as the water and borders of the Negro River, in the Amazon region of Brazil. Although it is a saprophyte and is generally considered non-pathogenic, sporadic cases of human infection have been described, mainly in young children and in immunodeficient individuals. Although rare, infections with C. violaceum are characterized by rapid dissemination and high mortality. With the complete genome sequence of C. violaceum now available, a detailed description of the molecular arsenal required for this bacterium's remarkable versatility has been revealed. Most importantly, a more detailed picture of its biotechnological properties, including the characteristic violacein pigment, has emerged. The complete genome sequence also enabled us to make a thorough examination of the repertoire of genes encoding probable virulence factors, which determine the potential for pathogenesis. We described a number of genes involved in infectious processes, such as host cell adhesion, "contact-dependent secretion" of factors that promote cell invasion, as well as other virulence factors, such as cytolytic proteins. We also described genes involved with the synthesis of lipopolysaccharides and proteoglycan, known to elicit the synthesis of pro-inflammatory cytokines and involved in the detoxification process, which may contribute to the evasion of the bacteria from the host immune response.
Assuntos
Chromobacterium/genética , Genoma Bacteriano , Lipopolissacarídeos/biossíntese , Peptidoglicano/biossíntese , Fatores de Virulência/genética , Aderência Bacteriana/genética , Chromobacterium/patogenicidade , Colicinas/biossíntese , Colicinas/genética , Proteínas Hemolisinas/biossíntese , Proteínas Hemolisinas/genética , Indóis , Peptidoglicano/genética , Virulência/genéticaRESUMO
Chromobacterium violaceum is a versatile, Gram-negative beta-protebacterium that grows in a variety of ecosystems in tropical and subtropical areas, such as the water and borders of the Negro River, in the Amazon region of Brazil. Although it is a saprophyte and is generally considered non-pathogenic, sporadic cases of human infection have been described, mainly in young children and in immunodeficient individuals. Although rare, infections with C. violaceum are characterized by rapid dissemination and high mortality. With the complete genome sequence of C. violaceum now available, a detailed description of the molecular arsenal required for this bacterium's remarkable versatility has been revealed. Most importantly, a more detailed picture of its biotechnological properties, including the characteristic violacein pigment, has emerged. The complete genome sequence also enabled us to make a thorough examination of the repertoire of genes encoding probable virulence factors, which determine the potential for pathogenesis. We described a number of genes involved in infectious processes, such as host cell adhesion, [quot ]contact-dependent secretion[quot ] of factors that promote cell invasion, as well as other virulence factors, such as cytolytic proteins. We also described genes involved with the synthesis of lipopolysaccharides and proteoglycan, known to elicit the synthesis of pro-inflammatory cytokines and involved in the detoxification process, which may contribute to the evasion of the bacteria from the host immune response
Assuntos
Chromobacterium/genética , Fatores de Virulência/genética , Genoma Bacteriano , Lipopolissacarídeos/biossíntese , Aderência Bacteriana/genética , Chromobacterium/patogenicidade , Colicinas/biossíntese , Colicinas/genética , Proteínas Hemolisinas/biossíntese , Proteínas Hemolisinas/genética , Indóis , Virulência/genéticaRESUMO
A case of Chromobacterium violaceum fatal septicemia is reported. The microorganism was isolated from six blood cultures and two suppurated skin lesions. It is the first such case described in Argentina, and it reinforces the need for prolonged treatment and careful clinical evaluation to ensure complete remission of human infections caused by this bacterium.