Caracterização de aspectos clínico-epidemiológicos e microbiológicos de amostras de Corynebacterium spp. isoladas de infecções hematogênicas de pacientes atendidos em hospital terciário da região metropolitana do Rio de Janeiro

Abstract

Corynebacteria are part of the commensal microbiota of humans and animals, and their isolation from clinical samples has been neglected by clinicians, since those microorganisms is usually considered as contaminants. The present study was conducted in a tertiary hospital in the city of Rio de Janeiro, and clinical strains of Corynebacterium spp. and other Gram positive bacilli of clinical importance, isolated from a total of 548 blood cultures of hospitalized patients in several hospital sections, from February to December 2015. The following species were characterized by the use of MALDI-TOF (Matrix Assisted laser Desorption Ionization – Time of Flight): Corynebacterium striatum (n=07), Corynebacterium amycolatum (n=03), Corynebacterium aurimucosum (n=01), Corynebacterium minutissimum (n=01), Brevibacterium ravespurgense (n=1), Dietzia maris (n=01), Listeria monocytogenes (n=02), Tsukamurella paurometabola (n=01). The dissemination of C. striatum was investigated using a Pulsed-field gel electrophoresis (PFGE) technique demonstrating the prevalence of a single clone named pulsotype IC, related to strains previously isolated in a hospital from Rio de Janeiro. C. striatum and C. amycolatum strains were resistant to multiple antimicrobials, and among the 24 antimicrobials tested, the C. striatum samples showed sensitivity only to vancomycin, linezolid and tetracycline. Both C. striatum and C. amycolatum strains produced biofilm at abiotic hydrophobic and hydrophilic surfaces. In addition, the strains were capable to adhere, survive and persist within type II pneumocytes (A549). In view of in vivo models, these pathogens were able to cause hematological changes in mice, as well as to promote mechanisms of pathogenicity and lethality to Caenorhabditis elegans helminth. These features corroborate the pathogenicity of C. striatum and C. amycolatum and their knowledge may support the development of strategies for the prevention, monitoring and control of infections by these agents in nosocomial environment. Thus, C. striatum and C. amycolatum should be considered as potential risk factors for hematogenous infections in hospitalized patients and surveillance measures should be taken to avoid preventing, monitoring and controlling such infections in nosocomial setting. Further studies on these and other virulence attributes and their relevance to the pathogenesis of corynebacteria remain necessary to minimize the involvement of these pathogens as etiological agents .