Corynebacterium spp. potencialmente uropatogênicas: caracterização molecular, descrição de novos táxons e investigação do potencial de virulência da espécie rara Corynebacterium mycetoides

Abstract

Urinary tract infection (UTI) caused by bacteria is considered the second most common infection in humans. Several factors can increase susceptibility to UTI, including age, sex, and comorbidities such as kidney disease. Although Gram-negative bacteria are among the main uropathogens, some species of Gram-positive bacteria have been increasingly related to UTIs, such as those of the Corynebacterium genus. In addition to UTI conditions, corynebacteria have also been increasingly associated with cases of invasive infections, especially in immunocompromised individuals. In recent decades, it’s important to note the appearance of multidrug-resistant isolates of these species in the whole world. However, microorganisms of this genus are often misidentified and/or discarded as contaminants when isolated from clinical materials, in part, due to the increasing description of new species because of advances in molecular studies and bioinformatics. Furthermore, limited identification methods based on cultures and biochemical tests still used in microbiology laboratories and contribute to this problem. In the present study, six isolates of Corynebacterium spp. from human urine of individuals with kidney problems were characterized through phenotypic tests and molecular analyses. Additionally, phylogenetic, and taxonomic studies of these isolates were carried out. Two new species of Corynebacterium were described and the pathogenic potential for the human urinary tract of the rare species, Corynebacterium mycetoides, were also reported for the first time. Among the isolates, five were erroneously identified based on conventional and molecular methodologies, such as the MALDI-TOF MS system and the 16S rRNA and rpoB genes sequencing. Phylogenetic and genomic taxonomy analyzes indicated the formation of two distinct groups comprising new species of Corynebacterium, whose proposed names were Corynebacterium guaraldiae sp. nov. and Corynebacterium hiratae sp. nov.. The rare isolate, C. mycetoides, was characterized as multidrug-resistant and with pathogenic potential for the urinary tract, being able to adhere to different surfaces of compounds widely used in the manufacture of hospital and outpatient supplies for urological use, in addition to being able to interact and survive within renal epithelial cells in vitro. The need for accurate and up-to-date data on Corynebacterium species is evident, particularly considering concerns about antimicrobial resistance and the pathogenicity of these microorganisms. Therefore, studies involving corynebacteria, especially those isolated from infections in humans, should be encouraged, not only so that knowledge about the microbial diversity of this genus is disseminated, but also to assist in the development of evidence-based protocols for the prevention and treatment of several infections caused by these microorganisms, either in the hospital environment or in the community.