Regulation of Erm(T) MLS Phenotype Expression in the Emergent Emm92 Type Group A Streptococcus

Overview

Journal NPJ Antimicrob Resist

Publisher Nature Portfolio

Date 2025 Jan 22

PMID 39843607

Authors

Lillie M Powell

Soo Jeon Choi

Megan E Grund

Ryan Demkowicz

Rita Berisio

P Rocco LaSala

Slawomir Lukomski

Affiliations

Soon will be listed here.

Abstract

In the last decade, invasive group A Streptococcus (iGAS) infections have doubled in the US, with equivalent increases in MLS (macrolide, lincosamide, and streptogramin B)-resistance. The emm92-type isolates carrying the erm(T) gene have been associated with an alarming emergence of iGAS infections in people who inject drugs or experience homelessness. Our goal was to elucidate the mechanisms behind inducible (iMLS) and constitutive (cMLS) resistance in emm92 isolates. Sequence analysis identified polymorphisms in the erm(T) regulatory region associated with cMLS resistance. RT-qPCR and RNAseq revealed increased erm(T) mRNA levels in iMLS isolates in response to erythromycin exposure, while cMLS isolates exhibited high erm(T) expression independent from antibiotic exposure. Transcription results were coupled with shifting levels of ribosomal methylation. A homology model of the ErmT enzyme identified structural elements and residues conserved in methyltransferases. Delayed growth of iMLS isolates cultured with erythromycin and increased clindamycin resistance in cMLS isolates were observed.

Citing Articles

Insights into MLS resistance in invasive group A streptococci in West Virginia, USA.

Powell L, Choi S, LaSala P, Lukomski S JAC Antimicrob Resist. 2025; 7(1):dlaf021.

PMID: 39973908 PMC: 11836684. DOI: 10.1093/jacamr/dlaf021.

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