Hypervirulence

Hypervirulent K. pneumoniae (hvKP), as opposed to ‘classical’ K. pneumoniae (cKP) can be distinguished by a combination of clinical and bacterial phenotypic features. These include the ability to establish infection in healthy host, unusual sites of infection, an ability for metastatic spread of the infection, and they often (but not always) present on an agar plate as hypermusocviscous which can be semi-quantitatively defined by a positive ‘string test’. The factor that mediates the expression of the hypermucoviscous phenotype is RmpA/RmpA2 (regulator of mucoid phenotype) encoded by 3 genes, chromosomally encoded rmpA and plasmid encoded p-rmpA and p-rmpA2. Studies have also shown that hvKP tend to fall within certain capsular serotypes often K1, but sometimes K2, K5, and a few others. Further hvKP strains have a high association with certain virulence factors that assist them in successful growth in their niche such as iron acquisition systems like the aerobactin and salmochelin operons as well as genes for yersinabactin and colibactin. This test uses PCR to look for K1, K2, and K5-serotype specific genes, the rmpA/rmpA2 genes, an aerobactin operon-specific gene (iucA), a salmochelin operon-specific gene (iroB), and yersinabactin (ybtA), and colibactin (clbA).

• Pneumonia
• Meningitis
• Bacteraemia
• Urinary tract infection
• Wound

Pure culture.

N/A

Send cultures as growth on culture medium or in transport medium. Culture vessel should be leak-proof or sealed appropriately.

Shipping of specimens shall be done by a TDG certified individual in accordance with TDG regulations. For additional information regarding classification of specimens for the purposes of shipping, consult either Part 2 Appendix 3 of the TDG Regulations or section 3.6.2 of the IATA Dangerous Goods Regulations as applicable.

N/A

Completed Antimicrobial Resistance and Nosocomial Infections Requisition.

  N/A

PCR based method. Results compared to known standards. This test uses PCR to look for K1, K2, and K5-serotype specific genes, the rmpA/rmpA2 genes, an aerobactin operon-specific gene (iucA), a salmochelin operon-specific gene (iroB), and yersinabactin (ybtA), and colibactin (clbA).

6 calendar days.

1. Zhang Y, C Zhao, Q Wang, X Wang, H Chen, H Li, F, Zhang, S Li, R Wang, H Wang. 2016. High prevalence of hypervirulent Klebsiella pneumoniae infection in China: geographic distribution, clinical characteristics and antimicrobial resistance. Antimicrob Agents Chemother doi:10.1128/AAC.01127-16.
2. Turton, JF, H Baklan, LK siu, ME Kaufmann, TL Pitt. 2008. Evaluation of a multiplex PCR for detection of serotypes K1, K2, and K5 in Klebsiella sp. and comparison of isolates within these serotypes. FEMS Microbiol Lett 284:247-252.
3. Russo TA, Olson R, Fang C-T, Stoesser N, Miller M, MacDonald U, Hutson A, Barker JH, La Hoz RM, Johnson JR. 2018. Identification of biomarkers for the differentiation of hypervirulent Klebsiella pneumoniae from classical K. pneumoniae. J Clin Microbiol 56:e00776-18.

Pathogen Safety Data Sheets: Infectious Substances – Klebsiella spp.