Gerardo Cortés Cortés: Antimicrobial resistance in Extraintestinal Pathogenic Escherichia coli
Gerardo Cortes Cortes
Dr. Cortés at the Camps Lab at UC Santa Cruz where he is developing his research project.

Gerardo Cortés Cortés was awarded the UC MEXUS-CONACYT Postdoctoral Fellowship in 2017 and 2018 to perform research on the genetic basis of antimicrobial resistance in extraintestinal pathogenic Escherichia coli, a pathogen that is a frequent cause of urinary tract infection and sepsis.

Dr. Cortés is working at the Department of Microbiology and Environmental Toxicology at UC Santa Cruz, under the mentorship of Professor Manel Camps. The Camps laboratory is known for its research on replication and maintenance of plasmids (circular double-stranded DNA molecules that are independent from chromosomal DNA). The lab also focuses on genetic adaptation and the evolution of new biochemical activities using extended spectrum beta-lactamase as a model.

The transfer of plasmids across cells, or conjugation, is one of the key processes facilitating the spread of antibiotic resistance, which continues to pose a growing threat to public health. Dr. Cortés’ project involves characterizing the conjugation efficiency of a set of sequenced, clinical strains of extraintestinal pathogenic E. Coli. His goal is to identify genomic features modulating conjugation efficiency as key regulators of resistance spread in the population.

His initial results indicate that IncF plasmids are largely responsible for carrying and mobilizing antibiotic resistance genes, with a conjugation efficiency that varies by three orders of magnitude between individual donor strains. This finding indicates a wide dynamic range of genetic elements modulating conjugation efficiency, which could be identified through genomic analysis.

Dr. Cortés is complementing a genomic approach with directed evolution, looking for plasmid mutants that exhibit altered conjugation efficiency. This complementary work involves two collaborations, one with Dr. Miriam Barlow from UC Merced where Dr. Cortés has recently applied a well-established conjugation protocol in a set of sequenced clinical E. coli strains. The second collaboration is with Dr. Luis Mota-Bravo, who has provided an optimized protocol for conjugation and has a large collection of multidrug resistant plasmids from a variety of environmental sources. Dr. Cortés will spend six months at UC Irvine with Dr. Mota-Bravo’s laboratory to become proficient in next generation sequencing and continue developing his leadership, communication, and managerial skills.

Through his postdoctoral stay and multi-campus collaborations, Dr. Cortés’ hopes to develop strategies to target plasmids to suppress drug resistance, and to monitor and slow down the spread of antibiotic resistance in the population.

Dr. Cortés can be reached at: gccortes@ucsc.edu

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Members of the Camps Lab hiking around the Wilder Ranch State Park at Santa Cruz, CA.
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Members of the Camps Lab at UC Santa Cruz. Dr. Cortés at far right.