RESUMO
Invasive infections caused by Corynebacterium diphtheriae in vaccinated and non-vaccinated individuals have been reported increasingly. In this study we used multilocus sequence typing (MLST) to study genetic relationships between six invasive strains of this bacterium isolated solely in the urban area of Rio de Janeiro, Brazil, during a 10-year period. Of note, all the strains rendered negative results in PCR reactions for the tox gene, and four strains presented an atypical sucrose-fermenting ability. Five strains represented new sequence types. MLST results did not support the hypothesis that invasive (sucrose-positive) strains of C. diphtheriae are part of a single clonal complex. Instead, one of the main findings of the study was that such strains can be normally found in clonal complexes with strains related to non-invasive disease. Comparative analyses with C. diphtheriae isolated in different countries provided further information on the geographical circulation of some sequence types.
Assuntos
Corynebacterium diphtheriae/genética , Difteria/microbiologia , Adolescente , Adulto , Idoso , Técnicas de Tipagem Bacteriana , Brasil/epidemiologia , Criança , Difteria/epidemiologia , Feminino , Humanos , Masculino , Tipagem de Sequências MultilocusRESUMO
Despite the existence of a vaccine against diphtheria, this disease remains endemic and is reemerging in several regions due to many factors, including variations in genes coding for virulence factors. One common feature of virulence factors is their high concentration in pathogenicity islands (PAIs), very unstable regions acquired via horizontal gene transfer, which has lead to the emergence of various bacterial pathogens. The 13 putative PAIs in Corynebacterium diphtheriae NCTC 13129 and the reemergence of this disease point to the great variability in the PAIs of this species, which may reflect on bacterial life style and physiological versatility. We investigated the relationships between the large number of PAIs in C. diphtheriae and the possible implications of their plasticity in virulence. The GenoFrag software was used to design primers to analyze the genome plasticity of two pathogenicity islands of the reference strain (PiCds 3 and 8) in 11 different strains. We found that PiCd 3 was absent in only two strains, showing genes playing putative important roles in virulence and that only one strain harbored PiCd 8, due to its location in a putative "hotspot" for horizontal gene transfer events.
Assuntos
Corynebacterium diphtheriae/patogenicidade , Reação em Cadeia da Polimerase/métodos , Virulência/genética , Sequência de Bases , Corynebacterium diphtheriae/genética , Primers do DNA , Genes BacterianosRESUMO
We conducted a seroepidemiological survey to determine the prevalence of caseous lymphadenitis (CLA) in goat herds in Minas Gerais state, Brazil. Serum samples were collected from goats (n=676) from 108 rural properties in 2001, covering most of the sub-regions of this ca. 586,500 square kilometer state. Antibodies against Corynebacterium pseudotuberculosis secreted proteins were detected by an indirect enzyme-linked immunosorbent assay (ELISA). Most of the animals (78.9%) tested positive for CLA; 98% of flocks presented at least one seropositive animal. Goats managed under an extensive production system had a significantly higher seroprevalence of CLA than those in intensive and semi-intensive operations. The age distribution of the animals in the flocks affected the prevalence of this disease; however, goat breed did not. We found seropositivity against C. pseudotuberculosis to be highly prevalent in these Brazilian goat herds; consequently, appropriate management practices for the control of CLA should be implemented.
Assuntos
Infecções por Corynebacterium/veterinária , Corynebacterium pseudotuberculosis , Doenças das Cabras/diagnóstico , Linfadenite/veterinária , Animais , Proteínas de Bactérias/imunologia , Brasil/epidemiologia , Infecções por Corynebacterium/diagnóstico , Infecções por Corynebacterium/epidemiologia , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Doenças das Cabras/epidemiologia , Doenças das Cabras/microbiologia , Cabras/microbiologia , Linfadenite/diagnóstico , Linfadenite/epidemiologia , Linfadenite/microbiologia , Masculino , Prevalência , Estudos SoroepidemiológicosRESUMO
The frequency and severity of human infections associated with Corynebacterium ulcerans appear to be increasing in different countries. Here, we describe the first C. ulcerans strain producing a diphtheria-like toxin isolated from an elderly woman with a fatal pulmonary infection and a history of leg skin ulcers in the Rio de Janeiro metropolitan area.
Assuntos
Broncopneumonia/microbiologia , Infecções por Corynebacterium/microbiologia , Corynebacterium/metabolismo , Toxoide Diftérico/biossíntese , Úlcera da Perna/microbiologia , Idoso de 80 Anos ou mais , Brasil/epidemiologia , Broncopneumonia/diagnóstico , Corynebacterium/isolamento & purificação , Infecções por Corynebacterium/diagnóstico , Infecções por Corynebacterium/epidemiologia , Evolução Fatal , Feminino , Humanos , Úlcera da Perna/diagnósticoRESUMO
Corynebacterium pseudotuberculosis, a Gram-positive intracellular pathogen, is the etiological agent of caseous lymphadenitis or CLA. This bacterium infects goats and sheep and causes great economic losses worldwide annually, mainly for goat producers. Despite its importance, CLA is still poorly characterized. However, with advances in the genomic field, many C. pseudotuberculosis genes have already been characterized, mainly those related to virulence such as phospholipase D. Here, we examined the use of the several available genes of C. pseudotuberculosis and reviewed their applications in vaccine construction, more efficient diagnostics for CLA, and control of this disease, among other applications.
Assuntos
Proteínas de Bactérias/genética , Infecções por Corynebacterium/diagnóstico , Corynebacterium pseudotuberculosis/genética , Animais , Proteínas de Bactérias/imunologia , Vacinas Bacterianas/genética , Vacinas Bacterianas/imunologia , Infecções por Corynebacterium/imunologia , Infecções por Corynebacterium/microbiologia , Corynebacterium pseudotuberculosis/imunologia , Corynebacterium pseudotuberculosis/patogenicidade , Linfadenite/diagnóstico , Linfadenite/imunologia , Linfadenite/microbiologia , Virulência/genéticaRESUMO
The frequency and severity of human infections associated with Corynebacterium ulcerans appear to be increasing in different countries. Here, we describe the first C. ulcerans strain producing a diphtheria-like toxin isolated from an elderly woman with a fatal pulmonary infection and a history of leg skin ulcers in the Rio de Janeiro metropolitan area.
Assuntos
Idoso de 80 Anos ou mais , Feminino , Humanos , Broncopneumonia/microbiologia , Infecções por Corynebacterium/microbiologia , Corynebacterium/metabolismo , Toxoide Diftérico/biossíntese , Úlcera da Perna/microbiologia , Brasil/epidemiologia , Broncopneumonia/diagnóstico , Infecções por Corynebacterium/diagnóstico , Infecções por Corynebacterium/epidemiologia , Corynebacterium/isolamento & purificação , Evolução Fatal , Úlcera da Perna/diagnósticoRESUMO
Corynebacterium pseudotuberculosis, a Gram-positive intracellular pathogen, is the etiological agent of caseous lymphadenitis or CLA. This bacterium infects goats and sheep and causes great economic losses worldwide annually, mainly for goat producers. Despite its importance, CLA is still poorly characterized. However, with advances in the genomic field, many C. pseudotuberculosis genes have already been characterized, mainly those related to virulence such as phospholipase D. Here, we examined the use of the several available genes of C. pseudotuberculosis and reviewed their applications in vaccine construction, more efficient diagnostics for CLA, and control of this disease, among other applications.