Transposon Mutagenesis Reveals Genetic Determinants Essential for Klebsiella pneumoniae Growth in Human Urine and Serum

Conceptos Básicos

Transposon mutagenesis and sequencing identified genes essential for Klebsiella pneumoniae growth in human urine and serum, providing insights into the molecular mechanisms underlying this pathogen's ability to colonize and survive in the human host.

Resumen

The study used a highly saturated transposon mutagenesis library in Klebsiella pneumoniae strain ECL8 to identify genes essential for growth in laboratory medium (LB), human urine, and human serum.

Key findings:

• 427 genes were identified as essential for growth on LB agar.
• 11 and 144 genes were found to decrease fitness for growth in human urine or serum, respectively.
• Genes involved in iron acquisition (fepB, fepD, exbB, exbD) were crucial for growth in urine, likely due to iron limitation.
• Genes involved in lipopolysaccharide (LPS) biosynthesis, O-antigen, and enterobacterial common antigen (ECA) were important for resistance to complement-mediated killing in serum.
• Validation experiments confirmed the importance of selected fitness genes for growth in urine or serum.

The study provides comprehensive insights into the genetic determinants that enable K. pneumoniae to colonize and survive in the human host, which could inform the development of new antimicrobial targets.

Estadísticas

Klebsiella pneumoniae ECL8 contains a 5.3 Mb chromosome and a 205 kb plasmid.
The transposon library contained over 1 million mutants with an average insertion every 9.93 bp.
427 genes were identified as essential for growth on LB agar.
11 and 144 genes decreased fitness for growth in human urine or serum, respectively.

Citas

"Transposon mutagenesis screen in Klebsiella pneumoniae identifies genetic determinants required for growth in human urine and serum"
"The identification of genetic determinants essential for growth and those required for survival of K. pneumoniae in vivo may help elucidate novel therapeutic targets"
"Our study provides insight into the molecular mechanisms that enable K. pneumoniae to survive in vivo and cause disease"

Ideas clave extraídas de

Transposon mutagenesis screen in Klebsiella pneumoniae identifies genetic determinants required for growth in human urine and serum

by Gray,J., Tor... a las www.biorxiv.org 06-01-2023

https://www.biorxiv.org/content/10.1101/2023.05.31.543172v2

Consultas más profundas

How do the genetic determinants identified in this study compare to those required for K. pneumoniae virulence in other host environments, such as the respiratory tract

In this study, the genetic determinants identified for K. pneumoniae growth in human urine and serum provide valuable insights into the pathogen's adaptation to these host environments. While the specific genetic determinants required for virulence in the respiratory tract may vary, there are common themes in the genetic factors essential for survival and pathogenesis in different host niches. For example, genes involved in iron acquisition, membrane stability, and stress response mechanisms are likely to be crucial for K. pneumoniae virulence in various host environments. The ability to resist complement-mediated killing, maintain membrane integrity, and acquire essential nutrients are key factors for bacterial survival and pathogenicity in different host niches. Additionally, the identification of genes associated with capsule biosynthesis, outer membrane proteins, and chaperones in this study highlights the importance of these factors in K. pneumoniae virulence, which may also be relevant in the respiratory tract.

What are the potential limitations of using pooled human urine and serum samples, and how could the experimental design be further refined to capture strain-specific or host-specific responses

Using pooled human urine and serum samples in experimental designs has certain limitations that may impact the generalizability of the findings. One limitation is the variability in the composition of urine and serum samples from different individuals, which may introduce confounding factors and make it challenging to capture strain-specific or host-specific responses. To address this limitation, future studies could consider using samples from a larger cohort of donors to account for inter-individual variability. Additionally, incorporating host-specific factors such as immune components or specific host cell types in the experimental setup could provide a more accurate representation of the host-pathogen interaction. Furthermore, utilizing strain-specific mutants or isogenic strains in the study design can help elucidate the role of specific genes in different host environments and their impact on virulence.

Given the importance of iron acquisition for K. pneumoniae growth in urine, what other nutrient sources or environmental cues might this pathogen utilize to adapt and thrive in the human host

In addition to iron acquisition, K. pneumoniae may utilize various nutrient sources and environmental cues to adapt and thrive in the human host. Some potential nutrient sources that the pathogen might exploit include amino acids, sugars, and other essential metabolites present in the host environment. K. pneumoniae may also utilize host-derived molecules or metabolic byproducts as nutrient sources to support its growth and survival. Environmental cues such as pH, oxygen levels, and host immune responses can also influence the pathogen's adaptation strategies. Understanding the diverse nutrient acquisition pathways and environmental cues that K. pneumoniae can exploit will provide valuable insights into its pathogenesis and potential therapeutic targets for intervention.