Beyond to the Stable: Role of the Insertion Sequences as Epidemiological Descriptors in Corynebacterium striatum

Abstract

In recent years, epidemiological studies of infectious agents have focused mainly on the pathogen and stable components of its genome. The use of these stable components makes it possible to know the evolutionary or epidemiological relationships of the isolates of a particular pathogen. Under this approach, focused on the pathogen, the identification of resistance genes is a complementary stage of a bacterial characterization process or an appendix of its epidemiological characterization, neglecting its genetic components’ acquisition or dispersal mechanisms. Today we know that a large part of antibiotic resistance is associated with mobile elements. Corynebacterium striatum, a bacterium from the normal skin microbiota, is also an opportunistic pathogen. In recent years, reports of infections and nosocomial outbreaks caused by antimicrobial multidrug-resistant C. striatum strains have been increasing worldwide. Despite the different existing mobile genomic elements, there is evidence that acquired resistance genes are coupled to insertion sequences in C. striatum. This perspective article reviews the insertion sequences linked to resistance genes, their relationship to evolutionary lineages, epidemiological characteristics, and the niches the strains inhabit. Finally, we evaluate the potential of the insertion sequences for their application as a descriptor of epidemiological scenarios, allowing us to anticipate the emergence of multidrug-resistant lineages.

First Pangenome of Corynebacterium rouxii, a Potentially Toxigenic Species of Corynebacterium diphtheriae Complex

“…All IS families in our strains were reported previously in Corynebacterium striatum isolates [63,66]. In this species, IS110, IS30, IS21, and especially IS3 and IS256 families were associated with antimicrobial resistance [63,66]. The association of IS families with antimicrobial resistance was also verified for other Corynebacterium species, including C. diphtheriae (IS3) and Corynebacterium jeikeium (IS3 and IS256) [66].…”

“…Among those, IS3, one of the largest IS families widely distributed in nature [66], had the highest number of copies in the C. rouxii strains. All IS families in our strains were reported previously in Corynebacterium striatum isolates [63,66]. In this species, IS110, IS30, IS21, and especially IS3 and IS256 families were associated with antimicrobial resistance [63,66].…”

“…A particular bacterial genome can present different types of IS in a wide range of copy numbers. They can move within the genome and be horizontally transferred as part of other mobile elements, such as phages and plasmids, and they can affect the genome structure and gene expression [63][64][65]. Presently, seven IS families were found in C. rouxii genomes (IS110, IS21, IS256, IS3, IS30, IS5 and ISL3).…”