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Epidemiological distribution, virulent genes and clinical characteristics of hypermucoviscous Klebsiella pneumonia in a Hospital

TIAN Li-jun1, WANG Xiao-li1, XIAO Shu-zhen2, SUN Jing-yong2, LIU Jia-lin1, QU Hong-ping1   

  1. 1. Department of Critical Care Medicine, 2. Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
  • Online:2017-01-28 Published:2017-01-19
  • Supported by:

    Project of Science and Technology Commission of Shanghai Municipality, 124119a6100; Shanghai Jiao Tong University Cooperation Grant of Medicine, Science, Engineering, YG2014MS57


Objective · To investigate the epidemiological distribution, antibiotic resistance and virulent genes of the hypermucoviscous Klebsiella pneumonia (hvKP) strains isolated from Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine and the clinical characteristics of these patients. Methods · Klebsiella pneumonia isolates were collected from hospitalized patients between September 2014 and March 2016. hvKP isolates were identified by string test. Capsular serotypes and virulent genes were detected using polymerase chain reaction (PCR). Clinical data of the hvKP-detected patients were retrospectively studied. Results · ① Of the 872 non-repetitive Klebsiella pneumonia strains, the prevalence of hvKP was 14.7% (128/872), and the highest prevalence of hvKP was 44.1% (15/34) from pus. Respiratory tract specimen was the most prevailing specimen of hvKP (70.3%, 90/128). ② Vast majority of the hvKP strains were susceptible to main antimicrobial agents, but two carbapenem-resistant hvKP strains were found. ③ Most of hvKP strains belonged to K1 (31.3%, 40/128) or K2 (32.0%, 41/128) capsular serotypes. 95.2% (20/21) of K57 serotype hvKP strains were isolated from respiratory tract. All hvKP strains were fimH, wabG and ureA positive. The incidences of p-RmpA and p-RmpA2 were 91.4% (117/128) and 82.8% (106/128) respectively, while the incidences of kfuBC and allS were 41.4% (53/128) and 27.3% (35/128) respectively, related to K1 serotype. The prevalence of capsular serotypes and virulent genes displayed no significant difference among different specimen types. ④ hvKP isolates occurred commonly in patients with diabetes mellitus (28.9%, 37/128) and cancer/immunosuppression (44.5%, 57/128). 60.9% (78/128) of the hvKP isolates could cause an infection, among which 47.4% (37/78) were community-acquired infection. The prevalence of capsular serotypes and virulent genes of hvKP also displayed no significant difference between infection group and non-infection group, as well as community-acquired infection group and hospital-acquired infection group. Conclusion · The prevalence of hvKP in Ruijin hospital was not high, and the dominant specimen of hvKP was respiratory tract specimen, some of which were colonization bacteria. K1/K2 capsular serotypes were the predominant serotypes, and almost all K57 capsular serotype hvKP strains were isolated from respiratory tract. The prevalence of capsular serotypes and virulent genes of hvKP was not significantly associated with specimen type, infection and source of infection. It is noteworthy that hvKP infection shows a convert from community-acquired to hospital-acquired.

Key words: Klebsiella pneumonia, hypermucoviscous, virulent gene, clinical characteristic