Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link

Volume 32, Number 3—March 2026

Research Letter

lsaC and Tandem lsaE-lnuB Resistance Genes in Invasive Group A Streptococcus

Bernard BeallComments to Author , Saundra Mathis, Zhongya Li, Joy Rivers, Anne-Kathryn Venero, Benjamin J. Metcalf, Lesley McGee, and Sopio Chochua
Author affiliation: Applied Science, Research & Technology, Inc., Atlanta, Georgia, USA (B. Beall, S. Mathis, Z. Li, A.-K. Venero); Centers for Disease Control and Prevention, Atlanta (J. Rivers, B.J. Metcalf, L. McGee, S. Chochua)

Main Article

Figure 2

Alignment of complete lsaE-carrying elements from study of repeated acquisitions of lsaC and tandem lsaE-lnuB resistance genes by group A Streptococcus. Alignments shown are from group A ABCs strains 2013217351 and 20231270 with partial elements from strains 20236407 and 20201347. Also included are complete elements from GAS2887Hub (8) and GBS strain SGB76 (GenBank accession no. KF772204). Antimicrobial resistance genes include 3 aminoglycoside 6-adenyltransferase genes (ant6, aph3, and ant9), and the streptothricin acetyltransferase gene aph3. Prokka annotations include topB (DNA topoisomerase genes), bin3 (DNA invertase gene), repB (DNA replication gene), tn-IS3 (IS3 family transposase gene), and xerC (tyrosine recombinase gene). Underlined bold text indicates the stop codon of the rplL gene in 2 strains. Scale bar indicates 5,000 base pairs. ABCs, Active Bacterial Core surveillance; sero, serotype; ST, sequence type.

Figure 2. Alignment of complete lsaE-carrying elements from study of repeated acquisitions of lsaC and tandem lsaE-lnuB resistance genes by group A Streptococcus. Alignments shown are from group A ABCs strains 2013217351 and 20231270 with partial elements from strains 20236407 and 20201347. Also included are complete elements from GAS2887Hub (8) and GBS strain SGB76 (GenBank accession no. KF772204). Antimicrobial resistance genes include 3 aminoglycoside 6-adenyltransferase genes (ant6, aph3, and ant9), and the streptothricin acetyltransferase gene aph3. Prokka annotations include topB (DNA topoisomerase genes), bin3 (DNA invertase gene), repB (DNA replication gene), tn-IS3 (IS3 family transposase gene), and xerC (tyrosine recombinase gene). Underlined bold text indicates the stop codon of the rplL gene in 2 strains. Scale bar indicates 5,000 base pairs. ABCs, Active Bacterial Core surveillance; sero, serotype; ST, sequence type.

Main Article

References
  1. Khan  ZZ. Group A streptococcal (GAS) infections treatment & management, 2024 [cited 2026 Feb 1]. https://emedicine.medscape.com/article/228936-treatment
  2. Li  Y, Rivers  J, Mathis  S, Li  Z, McGee  L, Chochua  S, et al. Continued increase of erythromycin nonsusceptibility and clindamycin nonsusceptibility among invasive group A streptococci driven by genomic clusters, United States, 2018–2019. Clin Infect Dis. 2023;76:e1266–9. DOIGoogle Scholar
  3. Schwarz  S, Shen  J, Kadlec  K, Wang  Y, Brenner Michael  G, Feßler  AT, et al. Lincosamides, streptogramins, phenicols, and pleuromutilins: mode of action and mechanisms of resistance. Cold Spring Harb Perspect Med. 2016;6:a027037. DOIGoogle Scholar
  4. File  TM Jr, Goldberg  L, Das  A, Sweeney  C, Saviski  J, Gelone  SP, et al. Efficacy and safety of intravenous-to-oral lefamulin, a pleuromutilin antibiotic, for the treatment of community-acquired bacterial pneumonia: the phase III Lefamulin Evaluation Against Pneumonia (LEAP 1) trial. Clin Infect Dis. 2019;69:1856–67. DOIGoogle Scholar
  5. Paukner  S, Sader  HS, Ivezic-Schoenfeld  Z, Jones  RN. Antimicrobial activity of the pleuromutilin antibiotic BC-3781 against bacterial pathogens isolated in the SENTRY antimicrobial surveillance program in 2010. Antimicrob Agents Chemother. 2013;57:4489–95. DOIGoogle Scholar
  6. Malbruny  B, Werno  AM, Murdoch  DR, Leclercq  R, Cattoir  V. Cross-resistance to lincosamides, streptogramins A, and pleuromutilins due to the lsa(C) gene in Streptococcus agalactiae UCN70. Antimicrob Agents Chemother. 2011;55:1470–4. DOIGoogle Scholar
  7. Douarre  PE, Sauvage  E, Poyart  C, Glaser  P. Host specificity in the diversity and transfer of lsa resistance genes in group B Streptococcus. J Antimicrob Chemother. 2015;70:3205–13.
  8. Berbel  D, Càmara  J, García  E, Tubau  F, Guérin  F, Giard  JC, et al. A novel genomic island harbouring lsa(E) and lnu(B) genes and a defective prophage in a Streptococcus pyogenes isolate resistant to lincosamide, streptogramin A and pleuromutilin antibiotics. Int J Antimicrob Agents. 2019;54:647–51. DOIGoogle Scholar
  9. Beall  B, Lin  W, Li  Z, Tran  T, Metcalf  BJ, Anderson  BJ, et al. Two independent acquisitions of multidrug resistance gene lsaC in Streptococcus pneumoniae serotype 20 multilocus sequence type 1257. Emerg Infect Dis. 2025;31:2098–108. DOIGoogle Scholar
  10. Chochua  S, Rivers  J, Mathis  S, Li  Z, Velusamy  S, McGee  L, et al. Emergent invasive group A Streptococcus dysgalactiae subsp. equisimilis, United States, 2015–2018. Emerg Infect Dis. 2019;25:1543–7. DOIGoogle Scholar

Main Article

Page created: February 23, 2026
Page updated: March 20, 2026
Page reviewed: March 20, 2026
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.
file_external