Yang Lu1,2, Yu Feng1,2, Alan McNally3, Zhiyong Zong1,2,4,5. 1. Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China. 2. Division of Infectious Diseases, State Key Laboratory of Biotherapy, Chengdu, China. 3. Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK. 4. Department of Infection Control, West China Hospital, Sichuan University, Chengdu, China. 5. Center for Pathogen Research, West China Hospital, Sichuan University, Chengdu, China.
Abstract
Background: A colistin-resistant mucoid Klebsiella strain was recovered from the blood of a patient in China. Hypervirulence has been reported in Klebsiella pneumoniae, but not in other Klebsiella spp. The strain was suspected to be hypervirulent and was therefore characterized. Methods: The strain was subjected to genome sequencing using both the short-read Illumina HiSeq X10 Sequencer and the long-read MinION sequencer. Precise species identification was established using average nucleotide identity based on genome sequences. Virulence and antimicrobial resistance genes were identified using ResFinder and the bigsdb database. Conjugation experiments were performed. Virulence was assessed using wax moth (Galleria mellonella) larvae with control Klebsiella strains of low virulence and hypervirulence. Results: The strain had a 5 553 341 bp circular chromosome and a 236 355 bp large plasmid. It was identified as Klebsiella variicola. The strain had multiple virulence genes encoding mucoid phenotype regulator (rmpA and rmpA2), aerobactin (iucABCD-iutA), salmochelin (iroBCDN) and yersiniabactin (irp1-2 and ybtAEPQSTUX) on the plasmid, which was not self-transmissible. It exhibited enhanced virulence in the larvae model, suggesting that the strain was hypervirulent. It was resistant to colistin (MIC = 8 mg/L) but was susceptible to amikacin, aztreonam, cefotaxime, ceftazidime, gentamicin, imipenem, meropenem, moxifloxacin, piperacillin/tazobactam, trimethoprim/sulfamethoxazole and tigecycline. The D150G substitution in PhoP, part of the PhoP-Q two-component system, which is known to mediate colistin resistance, was present in the strain. Conclusions: Hypervirulence is not restricted to K. pneumoniae; it is also seen in other Klebsiella spp. The convergence of colistin resistance and hypervirulence in K. variicola represents a new challenge for health.
Background: A colistin-resistant mucoid Klebsiella strain was recovered from the blood of a patient in China. Hypervirulence has been reported in Klebsiella pneumoniae, but not in other Klebsiella spp. The strain was suspected to be hypervirulent and was therefore characterized. Methods: The strain was subjected to genome sequencing using both the short-read Illumina HiSeq X10 Sequencer and the long-read MinION sequencer. Precise species identification was established using average nucleotide identity based on genome sequences. Virulence and antimicrobial resistance genes were identified using ResFinder and the bigsdb database. Conjugation experiments were performed. Virulence was assessed using wax moth (Galleria mellonella) larvae with control Klebsiella strains of low virulence and hypervirulence. Results: The strain had a 5 553 341 bp circular chromosome and a 236 355 bp large plasmid. It was identified as Klebsiella variicola. The strain had multiple virulence genes encoding mucoid phenotype regulator (rmpA and rmpA2), aerobactin (iucABCD-iutA), salmochelin (iroBCDN) and yersiniabactin (irp1-2 and ybtAEPQSTUX) on the plasmid, which was not self-transmissible. It exhibited enhanced virulence in the larvae model, suggesting that the strain was hypervirulent. It was resistant to colistin (MIC = 8 mg/L) but was susceptible to amikacin, aztreonam, cefotaxime, ceftazidime, gentamicin, imipenem, meropenem, moxifloxacin, piperacillin/tazobactam, trimethoprim/sulfamethoxazole and tigecycline. The D150G substitution in PhoP, part of the PhoP-Q two-component system, which is known to mediate colistin resistance, was present in the strain. Conclusions: Hypervirulence is not restricted to K. pneumoniae; it is also seen in other Klebsiella spp. The convergence of colistin resistance and hypervirulence in K. variicola represents a new challenge for health.
Authors: Tatiana Amabile de Campos; Felipe Marques de Almeida; Ana Paula Cardoso de Almeida; Rafael Nakamura-Silva; Mariana Oliveira-Silva; Isabela Felix Alencar de Sousa; Louise Cerdeira; Nilton Lincopan; Georgios Joannis Pappas; André Pitondo-Silva Journal: Front Microbiol Date: 2021-04-16 Impact factor: 5.640