Seroepidemiology of<i>Klebsiella pneumoniae</i>in an Australian Tertiary Hospital and Its Implications for Vaccine Development

Jenney, Adam; Clements, Abigail; Farn, Jacinta L.; Wijburg, Odilia L. C.; McGlinchey, Andrew; Spelman, Denis; Pitt, T. L.; Kaufmann, Mary E.; Liolios, Lisa; Moloney, M B; Wesselingh, Steven Lodewyk; Strugnell, Richard A.

doi:10.1128/jcm.44.1.102-107.2006

Cited by 62 publications

(67 citation statements)

References 31 publications

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“…A previous survey from Australia on the serotypes of 293 K. pneumoniae isolates (13) reported that 88 isolates (30%) were nontypeable by countercurrent immunoelectrophoresis (27), while 54 had a positive reaction for more than one serotype. Likewise, we had similar difficulties in serotyping using double immunodiffusion (26), as this study revealed.…”

Section: Discussionmentioning

confidence: 99%

Capsular Polysaccharide Synthesis Regions in Klebsiella pneumoniae Serotype K57 and a New Capsular Serotype

et al. 2008

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Community-acquired pyogenic liver abscess caused by Klebsiella pneumoniae is an emerging infectious disease. We explored the capsular polysaccharide synthesis (cps) regions of three non-K1, non-K2 K. pneumoniae strains, A1142, A7754, and A1517, from Taiwanese patients experiencing pyogenic liver abscess. Two of the strains, A1142 and A7754, belonged to capsular serotype K57, while the third belonged to a new capsular serotype, different from the previously reported 77 serotypes. Deletion and complementation experiments suggested that a unique K57 gene, a homologue of wzy, was essential for K57 capsular synthesis and confirmed that this gene cluster was a genetic coding region for K57. Compared to K1 and K2 strains, the three strains were all serum sensitive, suggesting that host factors might also be involved in the three patients. PCR using primers from specific genes for K57 was more sensitive and specific than traditional serotyping. The remaining strain, A1517, did not react to the antisera from any of the 77 serotypes, and none of the 77 reference strains reacted to the serum against this strain. Moreover, PCR analyses using various primer pairs from the serotype-specific open reading frames did not reveal cross-reactivity to any of the 77 reference strains, suggesting that this strain likely represents a new capsular type. We conclude that sequences from these two cps regions are very useful in detecting K57 and the new cps genotype.

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Section: Discussionmentioning

confidence: 99%

Capsular Polysaccharide Synthesis Regions in Klebsiella pneumoniae Serotype K57 and a New Capsular Serotype

et al. 2008

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“…The difficulties in determining capsular types in Klebsiella by serological diagnosis have been noted in several studies (36)(37)(38). Consequently, several techniques for molecular capsular typing were developed to circumvent these problems (7,9,39,40).…”

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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“…The bacterial strains and plasmids used in this study are listed in Table S1 in the supplemental material. K. pneumoniae AJ218 is a human urinary tract infection isolate (27). Unless otherwise stated, all bacterial strains were cultured at 37°C, with shaking, in Luria-Bertani (LB) broth overnight.…”

Section: Methodsmentioning

confidence: 99%

Positive Autoregulation ofmrkHIby the Cyclic Di-GMP-Dependent MrkH Protein in the Biofilm Regulatory Circuit of Klebsiella pneumoniae

Tan¹,

Wilksch²,

Hocking³

et al. 2015

J. Bacteriol.

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Klebsiella pneumoniae is an important cause of nosocomial infections, primarily through the formation of surface-associated biofilms to promote microbial colonization on host tissues. Expression of type 3 fimbriae by K. pneumoniae facilitates surface adherence, a process strongly activated by the cyclic di-GMP (c-di-GMP)-dependent transcriptional activator MrkH. In this study, we demonstrated the critical importance of MrkH in facilitating K. pneumoniae attachment on a variety of medically relevant materials and demonstrated the mechanism by which bacteria activate expression of type 3 fimbriae to colonize these materials. Sequence analysis revealed a putative MrkH recognition DNA sequence ("MrkH box"; TATCAA) located in the regulatory region of the mrkHI operon. Mutational analysis, electrophoretic mobility shift assay, and quantitative PCR experiments demonstrated that MrkH binds to the cognate DNA sequence to autoregulate mrkHI expression in a c-di-GMP-dependent manner. A half-turn deletion, but not a full-turn deletion, between the MrkH box and the ؊35 promoter element rendered MrkH ineffective in activating mrkHI expression, implying that a direct interaction between MrkH and RNA polymerase exists. In vivo analyses showed that residues L260, R265, N268, C269, E273, and I275 in the C-terminal domain of the RNA polymerase ␣ subunit are involved in the positive control of mrkHI expression by MrkH and revealed the regions of MrkH required for DNA binding and transcriptional activation. Taken together, the data suggest a model whereby c-di-GMP-dependent MrkH recruits RNA polymerase to the mrkHI promoter to autoactivate mrkH expression. Increased MrkH production subsequently drives mrkABCDF expression when activated by c-di-GMP, leading to biosynthesis of type 3 fimbriae and biofilm formation. IMPORTANCEBacterial biofilms can cause persistent infections that are refractory to antimicrobial treatments. This study investigated how a commonly encountered hospital-acquired pathogen, Klebsiella pneumoniae, controls the expression of MrkH, the principal regulator of type 3 fimbriae and biofilm formation. We discovered a regulatory circuit whereby MrkH acts as a c-di-GMP-dependent transcriptional activator of both the gene cluster of type 3 fimbriae and the mrkHI operon. In this positive-feedback loop, whereby MrkH activates its own production, K. pneumoniae has evolved a mechanism to ensure rapid MrkH production, expression of type 3 fimbriae, and subsequent biofilm formation under favorable conditions. Deciphering the molecular mechanisms of biofilm formation by bacterial pathogens is important for the development of innovative treatment strategies for biofilm infections. Biofilm-related infections substantially contribute to patient morbidity and place a significant burden on health care systems. The evolution of high-technology medicine such as intensive and invasive hospital care practices and immunosuppressive therapy and the emergence of multiply antibiotic-resistant organisms have contributed to the rise...

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Seroepidemiology ofKlebsiella pneumoniaein an Australian Tertiary Hospital and Its Implications for Vaccine Development

Cited by 62 publications

References 31 publications

Capsular Polysaccharide Synthesis Regions in Klebsiella pneumoniae Serotype K57 and a New Capsular Serotype

Capsular Polysaccharide Synthesis Regions in Klebsiella pneumoniae Serotype K57 and a New Capsular Serotype

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

Positive Autoregulation ofmrkHIby the Cyclic Di-GMP-Dependent MrkH Protein in the Biofilm Regulatory Circuit of Klebsiella pneumoniae

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