Microbiological and clinical characteristics of bacteraemia caused by the hypermucoviscosity phenotype of Klebsiella pneumoniae in Korea

To the Editor

We read with great interest the recently published article by Jung et al. [1]. The authors identified one ST380 serotype K2 blood isolate with liver abscess as the source of bacteraemia. We have recently reported three fatal bacteraemia episodes due to this clone in France [2]. However, these episodes were of unknown origin or related to pneumonia. To highlight the medical interest of data provided by Jung et al., we report the diagnosis in France of a liver abscess due to ST380, as well as one liver abscess case caused by a K2 isolate of ST375. The latter sequence type was also identified by Jung et al., but not from a liver abscess. The patient infected by isolate ST380 was a 68-year-old Tunisian man who had worked in France. He was hospitalized in France in order to explore a heterogeneous hepatic mass that was identified by echography when he visited Tatouine hospital in Tunisia for fever and chills. The hepatic abscess was complicated by a bilio-digestive fistula. The patient recovered following abscess and biliary drainage and amoxicillin + clavulanate antibiotic treatment. The second patient was a French woman with a 1-week history of fever and fatigue. She was a native of France, had no significant medical history and denied alcohol or drug abuse. She had travelled in Vietnam 2 years previously. Clinical examination showed a temperature of 40 °C and tenderness to percussion over the right upper quadrant of the abdomen. The remainder of the physical examination was unremarkable. Abdominal computed tomography showed a 10-cm diameter liver abscess. The patient recovered after abscess drainage and treatment with cefotaxime. Moreover, as with Jung et al. we detected the kfu gene, previously identified in non-K2 strains causing hepatic and extrahepatic abscesses, in strain ST380 but not in strain ST375 (PCR primers: 5′-AGAACCTTCCTCGCTGAACA-3′ and 5′-ATAGTAGGCGAGCACCGAGA-3′). In addition to the already recognized ST23-ST57 K1 clone, these results underline the emergence of at least two K. pneumoniae clones of capsular serotype K2, ST380 and ST375, which can cause liver abscess, and further emphasize the invasive potential of these two clones. Further studies are required to investigate the virulence traits of K2 strains.