F2F Poster 21st Lancefield International Symposium for Streptococci and Streptococcal Diseases 2022

Increasing antimicrobial resistance in human pathogenic Streptococcus dysgalactiae – of zoonotic origin? (#301)

Marte Glambek 1 , Steinar Skrede 1 2 , Alba Kaci 3 , Audun Sivertsen 4 , Hanna J Jørgensen 5 , Martin Steinbakk 3 6 , Christine M Jonassen 3 6 , Bård R Kittang 7 , Oddvar Oppegaard 1
  1. Department of Medicine, Haukeland University Hospital, Bergen, Norway
  2. Department of Clinical Science, University of Bergen, Bergen, Norway
  3. Center for Laboratory Medicine, Østfold Hospital Trust, Sarpsborg, Norway
  4. Department of Microbiology, Haukeland University Hospital, Bergen, Norway
  5. Norwegian Veterinary Institute, Oslo, Norway
  6. Norwegian Institute of Public Health, Oslo, Norway
  7. Department of Medicine, Haraldsplass Deaconess Hospital, Bergen, Norway

Background

Streptococcus dysgalactiae (SD) is a pathogen infecting humans as well as a diversity of animal species. Of concern, increasing resistance rates to erythromycin and clindamycin have been reported in human SD infections. We wished to explore antimicrobial resistance of SD in a One Health perspective and examine the potential contribution of zoonotic transmission of resistance determinants.

 

Methods

All cases of SD bacteraemia in Norway during 2018 were registered within a national surveillance program (NORM). The Norwegian Veterinary Institute prospectively collected all SD isolates from animal sources in Norway during 2018 – 2019. Phenotypic antimicrobial susceptibility testing was performed, and the resistome, mobilome and phylogenetic relationships were explored using whole genome analyses.

 

Results

A total of 277 human SD isolates and 144 animal isolates were included. Phylogenetic analysis clearly delineated the isolates in accordance with host species. Resistance to erythromycin and clindamycin was detected in 10 % of the human SD isolates, whereas in only 2 % of the animal isolates. All resistance genes were located on mobile genetic elements (MGEs), and close relationships between MGEs found in SD isolated from different hosts were identified. In addition, these MGEs showed a high degree of sequence similarity with MGEs found in other streptococci and enterococci.

 

Conclusions

We did not find evidence for an animal source of increasing resistance in human SD isolates. The data support SD living within ecological niches, with infrequent transitions between host species. Nevertheless, the dissemination of MGEs across bacterial species indicates numerous possible routes for spreading of antibiotic resistance.