Clinical laboratory study of carbapenem-resistant Klebsiella pneumoniae bloodstream infections at a hospital in Shanxi Province from 2015 to 2022
Objective To investigate the epidemiological and molecular characteristics of carbapenem-resistant Klebsiella pneumoniae isolated from blood cultures of patients with bloodstream infections in Shanxi Bethune Hospital from January 2015 to January 2022.Methods Klebsiella pneumoniae strains isolated from blood cultures of patients with bloodstream infections at Shanxi Bethune Hospital from January 2015 to January 2022 were collected for the study.Bacterial identification,drug sensitivity testing,and an improved carbapenem inactivation test were conducted to screen for carbapenem-resistant Klebsiella pneumoniae.Next-generation sequencing was performed on all strains,while whole genome sequencing was carried out on two strains that tested positive for the modified Hodge test indicating resistance to carbapenems.Results A total of 431 strains of Klebsiella pneumoniae were isolated from blood cultures of patients with bloodstream infections at Shanxi Bethune Hospital between January 2015 to January 2022,among which 33 were carbapenem-resistant strains including 11 highly virulent ones and 2 of these exhibited positive for the modified Hodge test.All strains were resistant to both ertapenem and imipenem,with only one strain being intermediate-resistant to meropenem.Among the 33 resistant strains,KPC-2 was detected in 26 strains and NDM-1 in 4;three strains possessed dual carbapenemase types(KPC-2/NDM-9,KPC-2/OXA-1,NDM-1/OXA-1),while four did not show any detectable carbapenem-resistance genes.Evolutionary analysis following next-generation sequencing revealed that the main sequence types(ST)among these isolates were ST11,ST147,and ST412;and the predominant serotypes were KL64,KL47,and KL25.The plasmid conjugal transfer experiments were successful in 18 strains.The two high virulence strains identified in the modified Hodge test were found to carry virulence and resistance plasmids upon whole genome sequencing.Conclusions The detection of carbapenem-resistant Klebsiella pneumoniae in patients with bloodstream infections has been increasing annually since 2015,with an outbreak occurring in 2021.The carbapenemase KPC-2 gene was the most prevalent,with the majority of strains being of the ST11/KL64 type.Strengthening screening and control measures for clinical drug-resistant strains is crucial for effective anti-infective treatment.
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