RESUMO
Corynebacterium striatum, a common constituent of the human skin microbiome, is now considered an emerging multidrug-resistant pathogen of immunocompromised and chronically ill patients. However, little is known about the molecular mechanisms in the transition from colonization to the multidrug-resistant (MDR) invasive phenotype in clinical isolates. This study performed a comprehensive pan-genomic analysis of C. striatum, including isolates from "normal skin microbiome" and from MDR infections, to gain insights into genetic factors contributing to pathogenicity and multidrug resistance in this species. For this, three novel genome sequences were obtained from clinical isolates of C. striatum of patients from Brazil, and other 24 complete or draft C. striatum genomes were retrieved from GenBank, including the ATCC6940 isolate from the Human Microbiome Project. Analysis of C. striatum strains demonstrated the presence of an open pan-genome (α = 0.852803) containing 3816 gene families, including 15 antimicrobial resistance (AMR) genes and 32 putative virulence factors. The core and accessory genomes included 1297 and 1307 genes, respectively. The identified AMR genes are primarily associated with resistance to aminoglycosides and tetracyclines. Of these, 66.6% are present in genomic islands, and four AMR genes, including aac(6')-ib7, are located in a class 1-integron. In conclusion, our data indicated that C. striatum possesses genomic characteristics favorable to the invasive phenotype, with high genomic plasticity, a robust genetic arsenal for iron acquisition, and important virulence determinants and AMR genes present in mobile genetic elements.
Assuntos
Antibacterianos , Corynebacterium , Humanos , Fenótipo , Fatores de Virulência/genética , Farmacorresistência Bacteriana Múltipla/genética , Testes de Sensibilidade MicrobianaRESUMO
A multiplex-PCR (mPCR) assay was designed with species-specific primers which generate amplicons of 226bp, 434bp and 106bp for differentiating the species C. striatum, C. amycolatum, and C. xerosis, respectively. mPCR results were 100% in agreement with identifications achieved by 16S rRNA and rpoB gene sequencing and by VITEK-MS.
Assuntos
Infecções por Corynebacterium/diagnóstico , Corynebacterium/classificação , Corynebacterium/genética , Tipagem Molecular/métodos , Reação em Cadeia da Polimerase Multiplex/métodos , Corynebacterium/isolamento & purificação , Infecções por Corynebacterium/microbiologia , Primers do DNA/genética , RNA Polimerases Dirigidas por DNA/genética , Humanos , RNA Ribossômico 16S/genéticaRESUMO
Non-diphtheriae Corynebacterium species have been increasingly recognized as the causative agents of infections in humans. Differential identification of these bacteria in the clinical microbiology laboratory by the most commonly used biochemical tests is challenging, and normally requires additional molecular methods. Herein, we present the annotated draft genome sequences of two isolates of "difficult-to-identify" human-pathogenic corynebacterial species: C. xerosis and C. minutissimum. The genome sequences of ca. 2.7 Mbp, with a mean number of 2,580 protein encoding genes, were also compared with the publicly available genome sequences of strains of C. amycolatum and C. striatum. These results will aid the exploration of novel biochemical reactions to improve existing identification tests as well as the development of more accurate molecular identification methods through detection of species-specific target genes for isolate's identification or drug susceptibility profiling.
RESUMO
We report the complete genome sequence and analysis of an invasive Corynebacterium diphtheriae strain that caused endocarditis in Rio de Janeiro, Brazil. It was selected for sequencing on the basis of the current relevance of nontoxigenic strains for public health. The genomic information was explored in the context of diversity, plasticity and genetic relatedness with other contemporary strains.
Assuntos
Corynebacterium diphtheriae/genética , DNA Bacteriano/genética , Genoma Bacteriano/genética , Brasil , Corynebacterium diphtheriae/classificação , Corynebacterium diphtheriae/patogenicidade , Difteria/genética , Filogenia , VirulênciaRESUMO
We report the complete genome sequence and analysis of an invasive Corynebacterium diphtheriae strain that caused endocarditis in Rio de Janeiro, Brazil. It was selected for sequencing on the basis of the current relevance of nontoxigenic strains for public health. The genomic information was explored in the context of diversity, plasticity and genetic relatedness with other contemporary strains.
Assuntos
Corynebacterium diphtheriae/genética , DNA Bacteriano/genética , Genoma Bacteriano/genética , Brasil , Corynebacterium diphtheriae/classificação , Corynebacterium diphtheriae/patogenicidade , Difteria/genética , Filogenia , VirulênciaRESUMO
Corynebacterium striatum commonly colonizes the normal skin and nasopharyngeal tract of humans; however, this potentially pathogenic bacterium has been identified as the causative agent of several nosocomial infections. The current study describes the draft genome of strain 1961 BR-RJ/09, isolated from the urine of a hospitalized patient from Brazil.
