biostudies-literatureChen HResearch Project of Jinan Microecological Biomedicine Shandong LaboratoryShandong Provincial Laboratory Projectthe Fundamental Research Funds for the Central Universities24https://www.ebi.ac.uk/biostudies/studies/S-EPMC10918965biostudies-literatureUnknown23(1)<h4>Background</h4>Klebsiella variicola is considered a newly emerging human pathogen. Clinical isolates of carbapenemase and broad-spectrum β-lactamase-producing K. variicola remain relatively uncommon. A strain of K. variicola 4253 was isolated from a clinical sample, and was identified to carry the bla_IMP-4 and bla_SFO-1 genes. This study aims to discern its antibiotic resistance phenotype and genomic characteristics.<h4>Methods</h4>Species identification was conducted using MALDI-TOF/MS. PCR identification confirmed the presence of the bla_IMP-4 and bla_SFO-1 genes. Antibiotic resistance phenotype and genomic characteristics were detected by antimicrobial susceptibility testing and whole-genome sequencing. Plasmid characterization was carried out through S1-PFGE, conjugation experiments, Southern blot, and comparative genomic analysis.<h4>Results</h4>K. variicola 4253 belonged to ST347, and demonstrated resistance to broad-spectrum β-lactamase drugs and tigecycline while being insensitive to imipenem and meropenem. The bla_IMP-4 and bla_SFO-1 genes harbored on the plasmid p4253-imp. The replicon type of p4253-imp was identified as IncHI5B, representing a multidrug-resistant plasmid capable of horizontal transfer and mediating the dissemination of drug resistance. The bla_IMP-4 gene was located on the In809-like integrative element (Intl1-bla_IMP-4-aacA4-catB3), which circulates in Acinetobacter and Enterobacteriaceae.<h4>Conclusions</h4>This study reports the presence of a strain of K. variicola, which is insensitive to tigecycline, carrying a plasmid harboring bla_IMP-4 and bla_SFO-1. It is highly likely that the strain acquired this plasmid through horizontal transfer. The bla_IMP-4 array (Intl1-bla_IMP-4-aacA4-catB3) is also mobile in Acinetobacter and Enterobacteriaceae. So it is essential to enhance clinical awareness and conduct epidemiological surveillance on multidrug-resistant K. variicola, conjugative plasmids carrying bla_IMP-4, and the In809 integrative element.Annals of clinical microbiology and antimicrobialsCoexistence of bla_IMP-4 and bla_SFO-1 in an IncHI5B plasmid harbored by tigecycline-non-susceptible Klebsiella variicola strain.PMC10918965SYS2022022022ZFJH003JNL-2022001AShen JZheng BLiu RChen HXu HLi LfalseCoexistence of bla_IMP-4 and bla_SFO-1 in an IncHI5B plasmid harbored by tigecycline-non-susceptible Klebsiella variicola strain.<h4>Background</h4>Klebsiella variicola is considered a newly emerging human pathogen. Clinical isolates of carbapenemase and broad-spectrum β-lactamase-producing K. variicola remain relatively uncommon. A strain of K. variicola 4253 was isolated from a clinical sample, and was identified to carry the bla_IMP-4 and bla_SFO-1 genes. This study aims to discern its antibiotic resistance phenotype and genomic characteristics.<h4>Methods</h4>Species identification was conducted using MALDI-TOF/MS. PCR identification confirmed the presence of the bla_IMP-4 and bla_SFO-1 genes. Antibiotic resistance phenotype and genomic characteristics were detected by antimicrobial susceptibility testing and whole-genome sequencing. Plasmid characterization was carried out through S1-PFGE, conjugation experiments, Southern blot, and comparative genomic analysis.<h4>Results</h4>K. variicola 4253 belonged to ST347, and demonstrated resistance to broad-spectrum β-lactamase drugs and tigecycline while being insensitive to imipenem and meropenem. The bla_IMP-4 and bla_SFO-1 genes harbored on the plasmid p4253-imp. The replicon type of p4253-imp was identified as IncHI5B, representing a multidrug-resistant plasmid capable of horizontal transfer and mediating the dissemination of drug resistance. The bla_IMP-4 gene was located on the In809-like integrative element (Intl1-bla_IMP-4-aacA4-catB3), which circulates in Acinetobacter and Enterobacteriaceae.<h4>Conclusions</h4>This study reports the presence of a strain of K. variicola, which is insensitive to tigecycline, carrying a plasmid harboring bla_IMP-4 and bla_SFO-1. It is highly likely that the strain acquired this plasmid through horizontal transfer. The bla_IMP-4 array (Intl1-bla_IMP-4-aacA4-catB3) is also mobile in Acinetobacter and Enterobacteriaceae. So it is essential to enhance clinical awareness and conduct epidemiological surveillance on multidrug-resistant K. variicola, conjugative plasmids carrying bla_IMP-4, and the In809 integrative element.2024-01-01T00:00:00Z2024 Mar2026-06-22T03:11:34.634Z2025-04-04T12:35:26.785ZS-EPMC109189653844892010.1186/s12941-024-00680-9