Abstract
Objectives: The discovery of mobile colistin resistance mcr-1, a plasmid-borne polymyxin resistance gene, highlights the potential for widespread resistance to the last-line polymyxins. In the present study, we investigated the impact of mcr-1 acquisition on polymyxin resistance and biological fitness in Klebsiella pneumoniae. Methods: K. pneumoniae B5055 was used as the parental strain for the construction of strains carrying vector only (pBBR1MCS-5) and mcr-1 recombinant plasmids (pmcr-1). Plasmid stability was determined by serial passaging for 10 consecutive days in antibiotic-free LB broth, followed by patching on gentamicin-containing and antibiotic-free LB agar plates. Lipid A was analysed using LC-MS. The biological fitness was examined using an in vitro competition assay analysed with flow cytometry. The in vivo fitness cost of mcr-1 was evaluated in a neutropenic mouse thigh infection model. Results: Increased polymyxin resistance was observed following acquisition of mcr-1 in K. pneumoniae B5055. The modification of lipid A with phosphoethanolamine following mcr-1 addition was demonstrated by lipid A profiling. The plasmid stability assay revealed the instability of the plasmid after acquiring mcr-1. Reduced in vitro biological fitness and in vivo growth were observed with the mcr-1-carrying K. pneumoniae strain. Conclusions: Although mcr-1 confers a moderate level of polymyxin resistance, it is associated with a significant biological fitness cost in K. pneumoniae. This indicates that mcr-1-mediated resistance in K. pneumoniae could be attenuated by limiting the usage of polymyxins.
| Original language | English |
|---|---|
| Pages (from-to) | 1604-1610 |
| Number of pages | 7 |
| Journal | Journal of Antimicrobial Chemotherapy |
| Volume | 73 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - 1 Jun 2018 |
Cite this
}
Fitness cost of mcr-1-mediated polymyxin resistance in Klebsiella pneumoniae. / Nang, Sue C; Morris, Faye C; McDonald, Michael J; Han, Meiling; Wang, Jiping; Strugnell, Richard A; Velkov, Tony; Li, Jian.
In: Journal of Antimicrobial Chemotherapy, Vol. 73, No. 6, 01.06.2018, p. 1604-1610.Research output: Contribution to journal › Article › Research › peer-review
TY - JOUR
T1 - Fitness cost of mcr-1-mediated polymyxin resistance in Klebsiella pneumoniae
AU - Nang, Sue C
AU - Morris, Faye C
AU - McDonald, Michael J
AU - Han, Meiling
AU - Wang, Jiping
AU - Strugnell, Richard A
AU - Velkov, Tony
AU - Li, Jian
PY - 2018/6/1
Y1 - 2018/6/1
N2 - Objectives: The discovery of mobile colistin resistance mcr-1, a plasmid-borne polymyxin resistance gene, highlights the potential for widespread resistance to the last-line polymyxins. In the present study, we investigated the impact of mcr-1 acquisition on polymyxin resistance and biological fitness in Klebsiella pneumoniae. Methods: K. pneumoniae B5055 was used as the parental strain for the construction of strains carrying vector only (pBBR1MCS-5) and mcr-1 recombinant plasmids (pmcr-1). Plasmid stability was determined by serial passaging for 10 consecutive days in antibiotic-free LB broth, followed by patching on gentamicin-containing and antibiotic-free LB agar plates. Lipid A was analysed using LC-MS. The biological fitness was examined using an in vitro competition assay analysed with flow cytometry. The in vivo fitness cost of mcr-1 was evaluated in a neutropenic mouse thigh infection model. Results: Increased polymyxin resistance was observed following acquisition of mcr-1 in K. pneumoniae B5055. The modification of lipid A with phosphoethanolamine following mcr-1 addition was demonstrated by lipid A profiling. The plasmid stability assay revealed the instability of the plasmid after acquiring mcr-1. Reduced in vitro biological fitness and in vivo growth were observed with the mcr-1-carrying K. pneumoniae strain. Conclusions: Although mcr-1 confers a moderate level of polymyxin resistance, it is associated with a significant biological fitness cost in K. pneumoniae. This indicates that mcr-1-mediated resistance in K. pneumoniae could be attenuated by limiting the usage of polymyxins.
AB - Objectives: The discovery of mobile colistin resistance mcr-1, a plasmid-borne polymyxin resistance gene, highlights the potential for widespread resistance to the last-line polymyxins. In the present study, we investigated the impact of mcr-1 acquisition on polymyxin resistance and biological fitness in Klebsiella pneumoniae. Methods: K. pneumoniae B5055 was used as the parental strain for the construction of strains carrying vector only (pBBR1MCS-5) and mcr-1 recombinant plasmids (pmcr-1). Plasmid stability was determined by serial passaging for 10 consecutive days in antibiotic-free LB broth, followed by patching on gentamicin-containing and antibiotic-free LB agar plates. Lipid A was analysed using LC-MS. The biological fitness was examined using an in vitro competition assay analysed with flow cytometry. The in vivo fitness cost of mcr-1 was evaluated in a neutropenic mouse thigh infection model. Results: Increased polymyxin resistance was observed following acquisition of mcr-1 in K. pneumoniae B5055. The modification of lipid A with phosphoethanolamine following mcr-1 addition was demonstrated by lipid A profiling. The plasmid stability assay revealed the instability of the plasmid after acquiring mcr-1. Reduced in vitro biological fitness and in vivo growth were observed with the mcr-1-carrying K. pneumoniae strain. Conclusions: Although mcr-1 confers a moderate level of polymyxin resistance, it is associated with a significant biological fitness cost in K. pneumoniae. This indicates that mcr-1-mediated resistance in K. pneumoniae could be attenuated by limiting the usage of polymyxins.
UR - http://www.scopus.com/inward/record.url?scp=85048120820&partnerID=8YFLogxK
U2 - 10.1093/jac/dky061
DO - 10.1093/jac/dky061
M3 - Article
AN - SCOPUS:85048120820
VL - 73
SP - 1604
EP - 1610
JO - Journal of Antimicrobial Chemotherapy
JF - Journal of Antimicrobial Chemotherapy
SN - 0305-7453
IS - 6
ER -