Klebsiella pneumoniae (Kp) reference strain Kp52.145 is widely used in experimental Klebsiella pathophysiology. Since 1935, only one other strain of the same sublineage (sequence type ST66, capsular serotype K2) was isolated (AJ210, Australia). Here, we describe a community-acquired invasive
infection caused by a ST66-K2 Kp strain in France. Four hypermucoviscous Kp isolates responsible for acute
otitis media,
meningitis, bacteraemia and
bacteriuria, respectively, were obtained from a patient with a history of chronic
alcoholism and
diabetes mellitus, and infected with HIV. The isolates were characterized by phenotypic and genomic methods. The four genetically identical ST66-K2 isolates presented a full antimicrobial susceptibility profile, including to
ampicillin, corresponding to a single strain (SB5881), which was more closely related to AJ210 (135 SNPs) than to Kp52.145 (388 SNPs).
Colibactin and
yersiniabactin gene clusters were present on the integrative and conjugative
element ICEKp10 in the chromosome. The two plasmids from Kp52.145 were detected in SB5881. In addition to carrying genes for
virulence factors RmpA,
aerobactin and
salmochelin, plasmid II has acquired in SB5881, the conjugation machinery gene cluster from plasmid I. We report the first case of
community-acquired infection caused by a hypervirulent ST66-K2 Kp strain in Europe. This demonstrates the long-term persistence of the high-virulence and laboratory model ST66-K2 sublineage. The combination of a conjugative apparatus and major virulence genes on a single plasmid may contribute to the co-occurrence of hypervirulence and multidrug resistance in single Kp strains.