Lipid A modification-induced colistin-resistant Klebsiella variicola from healthy adults.
J Med Microbiol
; 72(6)2023 Jun.
Article
de En
| MEDLINE
| ID: mdl-37261959
ABSTRACT
Background. Klebsiella variicola was once recognised as a benign plant-endosymbiont but recent case reports suggest that it is a newly emerging Gram-negative pathogen related to opportunistic infection of multiple sites in humans.Methods. Antimicrobial susceptibility testing was performed using broth microdilution method. To identify colistin resistance mechanisms, phoPQ, pmrAB, and mgrB were sequenced and their mRNA expression was analysed using quantitative real-time PCR. In addition, we tried to detect crrAB and mcr. The lipid A moieties of colistin-susceptible and -resistant isolates were analysed using MALDI-TOF.Results. Among the two K. variicola isolates, one is colistin-resistant, and another is colistin-susceptible. The colistin-resistant K. variicola isolate showed no mutations in phoPQ, pmrAB, and mgrB, and crrAB and mcr were not identified. However, its phoQ and pbgP expression was significantly higher and amino-arabinosylated lipid A with hexa-acylated species in lipopolysaccharide was identified.Conclusions. We found that colistin resistance in K. variicola was mediated by the modification of lipid A. Although the isolate was obtained from faecal samples of healthy adults, colistin-resistant K. variicola challenges public health as an opportunistic pathogen.
Mots clés
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Infections à Klebsiella
/
Colistine
Limites:
Adult
/
Humans
Langue:
En
Journal:
J Med Microbiol
Année:
2023
Type de document:
Article