emm Types and Macrolide Resistance among Invasive Group A Streptococcus in West Virginia

Chloe E. Chipman*, Lillie M. Powell*, Soo J. Choi, P. Rocco LaSala, and Slawomir Lukomski
Department of Microbiology, Immunology, and Cell Biology and Department of Pathology, West Virginia University School of Medicine, Morgantown, WV 26506

Presentation No.: 75

Assigned Category (Presentation Format): Health Sciences (Poster Presentations)

Student’s Major: Immunology and Medical Microbiology

Certain emm types of group A Streptococcus (GAS) cause invasive diseases that result in trauma and death. Macrolide antibiotics are used to treat GAS infections, though growing resistance has been reported globally. Here, we investigated 40 invasive GAS (iGAS) isolates collected from patients at J.W. Ruby Memorial Hospital in 2020-2021 for emm types and antibiotic resistance. emm typing was performed by sequencing the 5’-end of the emm gene and using a BLAST search against a Centers for Disease Control and Prevention database, whereas erythromycin-resistance genes were detected by PCR. Two emm types 92 (n=28) and 11 (n=6) were predominant. Macrolide resistance among emm92 isolates was conferred by gene ermT harbored on an R plasmid, while emm11 isolates harbored chromosomally-encoded determinants ermA, ermB, and mefA. Single isolates represented emm types 22, 28, 82, 83, 87, and 197, with resistance determinants similar to emm11 isolates. These results showed patterns in antibiotic resistance according to emm type. This study and further research will be important in determining treatment for iGAS infections as antibiotic resistance evolves in the species.

Funding: WVU IMMB Internship, 12300771

Program/mechanism supporting research/creative efforts: the WVU IMMB Undergraduate Research Internship Program (Jennifer Franko)