Ruiz-Rueda Lab probes the genetics of drug resistance in an emerging pathogen

Genomic data confirm that drug resistance is an intrinsic trait of the pathogenic bacterium Cupriavidus gilardii, CSUN microbiologists report in a paper just published in the journal mSphere.

The study is authored by CSUN Assistant Professor of Biology Cristian Ruiz Rueda, graduate student Ashley McCarley, undergraduate student Manuel Luis Espejo, and Lecturer Dana Harmon, alongside former Kerry Cooper at University of Arizona. The coauthors examined genome sequence data for Cupriavidus gilardii, a bacterium that is gaining increasing attention both as an infectious agent and because of its potential use in the detoxification of toxic compounds and other biotechnological applications.

In recent years, however, there have been an increasing number of reported infections, some of them fatal, caused by C. gilardii. These infections are hard to treat because C. gilardii is resistant to many antibiotics, including last-resort antibiotics such as carbapenems, and it also often becomes resistant to additional antibiotics during therapy. By comparing genome sequences for a strain of C. gilardii isolated from the environment ā€” specifically, the CSUN campus pond ā€” to strains isolated in clinical settings, Ruiz Rueda and his coauthors were able to zero in on the set of resistance genes shared by all the strains. This turned out to be most of them, confirming that drug resistance is a basic component of C. gilardii‘s biology ā€” that is, its antibiotic resistance appears not to have been acquired in horizontal gene transfer from other bacteria, or evolved as a new mutation selected by humans’ use of antibiotics.

The full paper is available open-access on the journal website.

Image: Detail of Ruiz et al (2019) Figure 1