<i>wzi</i>
            Gene Sequencing, a Rapid Method for Determination of Capsular Type for Klebsiella Strains

Brisse, Sylvain; Passet, Virginie; Haugaard, Anita Björk; Babosan, Anamaria; Kassis-Chikhani, Najiby; Struve, Carsten; Decré, Dominique

doi:10.1128/jcm.01924-13

Cited by 284 publications

(295 citation statements)

References 45 publications

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“…Consequently, several techniques for molecular capsular typing were developed to circumvent these problems (7,9,39,40). In addition, phage-borne capsular polysaccharide depolymerases recently were used in capsular typing of Klebsiella (6,22).…”

Section: Discussionmentioning

confidence: 99%

Klebsiella Phage ΦK64-1 Encodes Multiple Depolymerases for Multiple Host Capsular Types

Pan

Lin

Chen

et al. 2017

J Virol

120

111

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The genome of the multihost bacteriophage ⌽K64-1, capable of infecting Klebsiella capsular types K1, K11, K21, K25, K30, K35, K64, and K69, as well as new capsular types KN4 and KN5, was analyzed and revealed that 11 genes (S1-1, S1-2, S1-3, S2-1, S2-2, S2-3, S2-4, S2-5, S2-6, S2-7, and S2-8) encode proteins with amino acid sequence similarity to tail fibers/spikes or lyases. S2-5 previously was shown to encode a K64 capsule depolymerase (K64dep). Specific capsule-degrading activities of an additional eight putative capsule depolymerases (S2-4 against K1, S1-1 against K11, S1-3 against K21, S2-2 against K25, S2-6 against K30/K69, S2-3 against K35, S1-2 against KN4, and S2-1 against KN5) was demonstrated by expression and purification of the recombinant proteins. Consistent with the capsular type-specific depolymerization activity of these gene products, phage mutants of S1-2, S2-2, S2-3, or S2-6 lost infectivity for KN4, K25, K35, or K30/K69, respectively, indicating that capsule depolymerase is crucial for infecting specific hosts. In conclusion, we identified nine functional capsule depolymerase-encoding genes in a bacteriophage and correlated activities of the gene products to all ten hosts of this phage, providing an example of type-specific host infection mechanisms in a multihost bacteriophage.IMPORTANCE We currently identified eight novel capsule depolymerases in a multihost Klebsiella bacteriophage and correlated the activities of the gene products to all hosts of this phage, providing an example of carriage of multiple depolymerases in a phage with a wide capsular type host spectrum. Moreover, we also established a recombineering system for modification of Klebsiella bacteriophage genomes and demonstrated the importance of capsule depolymerase for infecting specific hosts. Based on the powerful tool for modification of phage genome, further studies can be conducted to improve the understanding of mechanistic details of Klebsiella phage infection. Furthermore, the newly identified capsule depolymerases will be of great value for applications in capsular typing.KEYWORDS Klebsiella, bacteriophage, capsular type, capsule depolymerase, multiple host T he genus Klebsiella, especially the species Klebsiella pneumoniae, is an important human pathogen that causes a wide range of diseases, including both community and hospital-acquired infections. It is associated with septicemia, pneumonia, and urinary tract infections (1, 2) and also is responsible for a globally emerging disease, pyogenic liver abscess complicated with metastatic meningitis and endophthalmitis (3,4).Klebsiella spp. typically display a layer of thick, polysaccharide-based capsule on their surfaces. The expression of diverse capsule structure caused by different sugar compositions and linkages divide them into distinct serotypes. In addition, genetic

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Section: Discussionmentioning

confidence: 99%

Klebsiella Phage ΦK64-1 Encodes Multiple Depolymerases for Multiple Host Capsular Types

Pan

Lin

Chen

et al. 2017

J Virol

120

111

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“…5,6 These conserved genes have also been proposed for the identification of capsular serotypes, including wzi and wzc. 5,20 In this study, we have tried to elucidate the role of these conserved genes in virulence and whether they can function in a similar manner after exchanging a homologous gene from one serotype to another. We found these genes can be categorized into 3 types according to their different effects on the degree of virulence.…”

Section: Discussionmentioning

confidence: 99%

Effect in virulence of switching conserved homologous capsular polysaccharide genes fromKlebsiella pneumoniaeserotype K1 into K20

et al. 2016

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The capsular polysaccharides in different serotypes of Klebsiella pneumoniae (KP) coded by the (CPS) gene cluster are characterized by a conserved and a hyper-variable region. We performed a virulence study by switching genes in the highly conserved region of the CPS cluster between strains. Six genes in the CPS conserved region in serotype K20, including galF, acidPPc, wzi, wza, wzb and wzc, were knocked out and replaced by the homologous genes from serotype K1. Compared to the parental K20 strain, the mutants showed a decline in lethality (LD 50 ) in mice from 10-fold to > 10 5 -fold and were categorized in terms of the effect on virulence as low (L) for galF and acidPPC, moderate (M) for wzi, and high (H) for wza, wzb and wzc. Although substituting the acidPPC gene from K1 for acidPPC in the K20 strain fully restored virulence, substitution with the wzi, wza, wzb or wzc homologs from K1 did not. The restoration with wzi from K1 led to a partial restoration of virulence, with the LD 50 in mice changing from 10 4 to 10 3 CFU . For the wza, wzb and wzc genes, Complementation of K20 wza, wzb and wzc from K1 resulted in varied degrees of lethality in mice. Variable improvement in serum killing and phagocytosis was observed when the knockout mutants were compared with the geneswitched strains. In conclusion, homologous genes for capsule synthesis failed to exhibit the same functionality when switched between serotypes and virulence was decreased in different degree in according to the genes' homology.

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“…K antigens have been traditionally assigned by using serological methods (201). Recently, however, K-antigen typing is often performed by sequencing of the wzi locus (206)(207)(208)(209)(210). This locus is present in all capsular types of K. pneumoniae, and different wzi locus sequences are strongly associated with specific K antigens.…”

Section: Capsulementioning

confidence: 99%

Klebsiella pneumoniae: Going on the Offense with a Strong Defense

Paczosa

Mecsas

2016

Microbiol Mol Biol Rev

1,290

1,345

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SUMMARYKlebsiella pneumoniaecauses a wide range of infections, including pneumonias, urinary tract infections, bacteremias, and liver abscesses. Historically,K. pneumoniaehas caused serious infection primarily in immunocompromised individuals, but the recent emergence and spread of hypervirulent strains have broadened the number of people susceptible to infections to include those who are healthy and immunosufficient. Furthermore,K. pneumoniaestrains have become increasingly resistant to antibiotics, rendering infection by these strains very challenging to treat. The emergence of hypervirulent and antibiotic-resistant strains has driven a number of recent studies. Work has described the worldwide spread of one drug-resistant strain and a host defense axis, interleukin-17 (IL-17), that is important for controlling infection. Four factors, capsule, lipopolysaccharide, fimbriae, and siderophores, have been well studied and are important for virulence in at least one infection model. Several other factors have been less well characterized but are also important in at least one infection model. However, there is a significant amount of heterogeneity inK. pneumoniaestrains, and not every factor plays the same critical role in all virulentKlebsiellastrains. Recent studies have identified additionalK. pneumoniaevirulence factors and led to more insights about factors important for the growth of this pathogen at a variety of tissue sites. Many of these genes encode proteins that function in metabolism and the regulation of transcription. However, much work is left to be done in characterizing these newly discovered factors, understanding how infections differ between healthy and immunocompromised patients, and identifying attractive bacterial or host targets for treating these infections.

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wzi Gene Sequencing, a Rapid Method for Determination of Capsular Type for Klebsiella Strains

Cited by 284 publications

References 45 publications

Klebsiella Phage ΦK64-1 Encodes Multiple Depolymerases for Multiple Host Capsular Types

Klebsiella Phage ΦK64-1 Encodes Multiple Depolymerases for Multiple Host Capsular Types

Effect in virulence of switching conserved homologous capsular polysaccharide genes fromKlebsiella pneumoniaeserotype K1 into K20

Klebsiella pneumoniae: Going on the Offense with a Strong Defense

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