One of the main K. pneumoniae laboratory reference strains is Kp52.145 (=B5055). It was isolated in 1935 in Indonesia and was selected as the reference strain of capsular serotype K2. Kp52.145 belongs to Sequence-type (ST) 66 and is a highly virulent strain from which the virulence plasmid of Klebsiella and the role of aerobactin in virulence were discovered. This strain is also used as a reference strain for its ability to escape molecular pathways relevant in the activation of the immune response. Important virulence factors (plasmid-carried rmpA/rmpA2, iut, iro, and integrative conjugative elements (ICEs)-carried yersiniabactin [ybt] and colibactin [clb]) are harbored by this strain. In contrast to the prominent role of this reference strain in laboratory work, after almost a century, the K. pneumoniae sublineage ST66-K2 was almost never observed again in clinical and epidemiological studies, with only one report in in Australia in 2002 (isolate AJ210). In this study, we describe the clinical and molecular characteristics of a ST66-K2 community-acquired infection in France in 2018. Four Kp isolates were recovered from blood (18/02; SB5881), urine (18/02; SB5882), CSF (19/02; SB5883) and otorrhea (19/02; SB5884) samples. They were involved in the different infectious site (bacteremia, bacteriuria, meningitis and acute otitis media, respectively). The four isolates were analyzed phenotypically and genotypically.
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