The Case Report of Klebsiella quasipneumoniae subsp. similipneumoniae ST138-K1/O5 in a Clinically Vulnerable Patient

Infections caused by the Klebsiella pneumoniae species complex (KpSC) are particularly challenging to manage, especially in healthcare systems. Members of the KpSC are frequently identified as K. pneumoniae by conventional automated or proteomic systems. The aim of this study was to characterize a KpSC isolate obtained from a clinically vulnerable patient and to describe the patient’s clinical features. The patient’s clinical data were obtained from the medical history. Identification and antibiotic susceptibility testing were performed using different approaches. Whole Genome Sequencing (WGS) was conducted, and in silico analysis using available databases was undertaken to predict antibiotic resistance determinants, plasmid incompatibility groups, sequence type (ST), capsular K-type, O-antigen, and virulence genes. A K. pneumoniae isolate (K87) was recovered from blood cultures and characterized as K. quasipneumoniae subsp. similipneumoniae by WGS. K87 belongs to ST138 and carries the predicted K1/O5 locus and the blaOKP-B-2 gene. The virulome included type III fimbriae, ferric iron uptake systems, and metabolic functions. After months of hospitalization, the patient showed clinical deterioration and died. This is the first report of bacteremia caused by Klebsiella quasipneumoniae subsp. similipneumoniae ST138-K1/O5 in a clinically vulnerable patient in Uruguay (South America).