Objective: To describe the clinical characteristics of hypervirulent Klebsiella pneumoniae (hvKP)
infection. To analyze the
antibiotic susceptibility of hvKP to provide the empiric
antibiotic options. To investigate
capsule serotype and sequence type (ST) of hvKP and their correlation with clinical profiles. Methods: hvKP was defined as bacteria isolated from patients with community-acquired
pyogenic liver abscess (CA-PLA) with
co-infection sites outside liver or a
bloodstream infection in a host without underlying
biliary tract diseases. Patients with CA-PLA hospitalized in the First Hospital of China Medical University were retrospectively analyzed from January 2011 to December 2017.
Antibiotic susceptibility was detected by automatic bacterial identification and
antibiotic susceptibility analysis system in vitro. Polymerase chain reaction method and gene sequencing were used to detect the main
capsule serotype and ST. Results: A total of 140 cases with hvKP
infection were enrolled. The
co-infections outside
liver abscess included 98
bloodstream infections, 53
pneumonia, 11 perianal
abscess, 10 urinary system
infections, 3
subphrenic abscess, 3
endophthalmitis, 2 spleen
abscess, and other miscellaneous
infections including 1
peritonitis, 1 skin and
soft tissue infection, 1
myelitis, 1
colitis, 1 psoas major
abscess and 1 myocardial
abscess. Among the 140 cases, 106 presented with single
co-infection site, 32 with 2 sites, and 2 with 3 sites. HvKP manifested high
antibiotic susceptibility up to 80% for most commonly used
antibiotics.
Capsule serotyping of 43 revived isolates indicated that K1 serotype accounted for 53.49% (23/43), K2 34.88 (15/43), K54 2.33% (1/43), K57 2.33% (1/43), and other serotypes 6.98%(3/43). There was no significant distribution among K1, K2, K54 and K57 of hvKP
capsule serotypes in patients with or without
diabetes mellitus (P>0.05). Multilocus sequence typing (MLST) suggested that ST23 and ST65 were predominant accounting for 39.53% (17/43) and 25.58% (11/43) respectively. No serotype or ST predominance was seen in any of the clinical
infections. Conclusion: HvKP is related to a wide spectrum of
infectious diseases, including multiple extrahepatic sites and
bloodstream infections besides CA-PLA with high
antibiotic susceptibility. K1 and K2 are the predominant
capsule serotypes, and ST 23 and ST65 are the predominant sequence types.