Oral Presentation Australian Society for Microbiology Annual Scientific Meeting 2022

Plasmids of multidrug resistant Klebsiella pneumoniae pathogenic clones. (82590)

Carola Venturini 1 2 , Sally Partridge 3 , Alison Collins 4 , Alicia Fajardo-Lubian 2 5 , Jon Iredell 3 , Ruth Zadoks 1 , Jacqueline Norris 1
  1. Sydney School of Veterinary Science, The University of Sydney, Camperdown, Australia
  2. Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research, Westmead, NSW, Australia
  3. Centre for Infectious Diseases and Microbiology, Westmead Institute for Medical Research, The University of Sydney and Westmead Hospital, Westmead, NSW, Australia
  4. NSW Department of Primary Industries - Regional NSW, Menangle, NSW, Australia
  5. Sydney School of Medicine, The University of Sydney, Sydney, NSW, Australia

Multidrug resistant (MDR) Klebsiella pneumoniae, refractory to commonly used antibiotics, are main agents of life-threatening sepsis in humans (1) and can cause severe disease in animals (e.g. pneumonia) (2). The global epidemiology of K. pneumoniae infection is dominated by the spread of pathogenic clones, belonging to either highly resistant sequence types (ST) (e.g. ST307) or highly virulent ones (e.g. ST25), on a seemingly separate evolution path (3). MDR determinants are commonly localised on large transferable plasmids which seem to be more diverse in highly resistant clones. We have characterised multiple co-existing K. pneumoniae isolates from a horse infection and found they belonged to different clonal groups known to cause disease in humans. We found little difference between these isolates and those of same ST isolated from humans, except for MDR plasmid carriage (4). To better understand the diversity of MDR plasmids in animal and human reservoirs and their link to specific pathogenic clones, we further characterised the plasmid content of K. pneumoniae from pigs, chickens, and cows isolated in Australia (2011-2022; n≥60), by whole genome sequencing and bioinformatic analysis, and compared them to human strains of the same ST. Most isolates, independently of ST, carried related MDR F-type plasmids with the same accessory genes likely to favour niche specialization (e.g. silver, copper and arsenic resistance; urea and iron transport etc.) and in all STs multidrug resistance was associated with plasmid carriage. FIIK7-type and an FIBK-type replicons, related to pKPN3-307_type A plasmids found in humans (3), were predominant, while unique HI3 plasmids (IncFIB(pNDM-MAR) and IncHI1B(pNDM-MAR)-like replicons) were detected in most STs except those carrying hypervirulence determinants (i.e. ST25). Not surprisingly, multi-resistance regions similar to those seen in the animal plasmids have also been described before in plasmids from human isolates. Different clones have different virulence attributes but share some of their accessory, mobilizable replicons highlighting once more the importance of cross-monitoring of environmental and human reservoirs of multidrug resistant pathogens.

  1. World Health Organization (WHO). Antimicrobial Resistance Global Report on Surveillance: 2014 Summary (WHO, Geneva, Switzerland, 2014)
  2. Paczosa MK Mecsas J. 2016 K. pneumoniae: going on the offense with a strong defence. MMB Rev 80:629-61
  3. Wyres KL et al. 2019 Distinct evolutionary dynamics of horizontal gene transfer in drug resistant and virulent clones of K. pneumoniae. PLoS Genet 15:e1008114
  4. Venturini C et al. 2022 Co-occurrence of multidrug resistant K. pneumoniae pathogenic clones of human relevance in an equine pneumonia case. mSpectrum in press (accepted 13-04-22)