Project description:Antibiotic use can lead to expansion of multi-drug resistant pathobionts within the gut microbiome that can cause life-threatening infections. Selective alternatives to conventional antibiotics are in dire need. Here, we describe a Klebsiella PhageBank that enables the rapid design of antimicrobial bacteriophage cocktails to treat multi-drug resistant Klebsiella pneumoniae. Using a transposon library in carbapenem-resistant K. pneumoniae, we identified host factors required for phage infection in major Klebsiella phage families. Leveraging the diversity of the PhageBank and experimental evolution strategies, we formulated combinations of phages that minimize the occurrence of phage resistance in vitro. Optimized bacteriophage cocktails selectively suppressed the burden of multi-drug resistant K. pneumoniae in the mouse gut microbiome and drove bacterial populations to lose key virulence factors that act as phage receptors. Further, phage-mediated diversification of bacterial populations in the gut enabled co-evolution of phage variants with higher virulence and a broader host range. Altogether, the Klebsiella PhageBank represents a roadmap for both phage researchers and clinicians to enable phage therapy against a critical multidrug-resistant human pathogen.
Project description:Klebsiella pneumoniae is an arising threat to human health. However, host immune responses in response to this bacterium remain to be elucidated. The goal of this study was to identify the dominant host immune responses associated with Klebsiella pneumoniae pulmonary infection. Pulmonary mRNA profiles of 6-8-weeks-old BALB/c mice infected with/without Klebsiella pneumoniae were generated by deep sequencing using Illumina Novaseq 6000. qRT–PCR validation was performed using SYBR Green assays. Using KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis, we identified several immune associated pathways, including complement and coagulation cascades, Toll-like receptor signaling pathway, Rap1 signaling pathway, chemokine signaling pathway, TNF signaling pathway, phagosome and NOD-like receptor signaling pathway, were involved in Klebsiella pneumoniae pulmonary infection. Using ICEPOP (Immune CEll POPulation) analysis, we found that several cell types were involved in the host immune response to Klebsiella pneumoniae pulmonary infection, including dendritic cells, macrophages, monocytes, NK (natural killer) cells, stromal cells. Further, IL-17 chemokines were significantly increased during Klebsiella pneumoniae infection. This study provided evidence for further studying the pathogenic mechanism of Klebsiella pneumoniae pneumonia infection.
Project description:Increasing evidence highlights the role of bacteria in the physiopathology of cancer. However, the underlying molecular mechanisms remains poorly understood. Several cancer-associated bacteria have been shown to produce toxins which modulate the tumor suppressor p53 and thereby interfere with the host defense against tumorigenesis. Here, we show that lipopolysaccharides from Klebsiella pneumoniae (Kp) strongly inhibit the host p53 pathway and impairs p53 transcriptional activity upon DNA damage and oncogenic stress, preventing its tumor suppressive function.
Project description:The emergence and spread of polymyxin resistance, especially among Klebsiella pneumoniae isolates threaten the effective management of infections. This study profiled for polymyxin resistance mechanisms and investigated the activity of polymyxins plus vancomycin against carbapenem- and polymyxin-resistant K. pneumoniae.
Project description:Cyanobacteria are highly abundant in the oceans where they are constantly exposed to lytic viruses. Some viruses are restricted to a narrow host range while others infect a broad range of hosts. It is currently unknown whether broad-host range phages employ the same infection program, or regulate their program in a host-specific manner to accommodate for the different genetic makeup and defense systems of each host. Here we used a combination of microarray and RNA-seq analyses to investigate the interaction of three phylogentically distinct Synechococcus strains, WH7803, WH8102, and WH8109, with the broad-host range T4-like myovirus, Syn9, during infection. Strikingly, we found that the phage led a nearly identical expression program in the three hosts despite considerable differences in host gene content. On the other hand, host responses to infection involved mainly host-specific genes, suggesting variable attempts at defense against infection. A large number of responsive host genes were located in hypervariable genomic islands, substantiating genomic islands as a major axis of phage-bacteria interactions in cyanobacteria. Furthermore, transcriptome analyses and experimental determination of the complete phage promoter map revealed three temporally regulated modules and not two as previously thought for cyanophages. In contrast to T4, an extensive, previously unknown regulatory motif drives expression of early genes and host-like promoters drive middle-gene expression. These promoters are highly conserved among cyanophages and host-like middle promoters extend to other T4-like phages, indicating that the well-known mode of regulation in T4 is not the rule among the broad family of T4-like phages. We investigated the infection process and transcriptional program of the P-TIM40 cyanophage during infection of a Prochlorococcus NATL2A host. The results are discussed in conjunction with results obtained from the infection process for the Syn9 cyanophage in three different Synechococcus hosts: WH7803 (Dufresne et al. 2008), WH8102 (Palenik et al. 2003) and WH8109 (sequenced as part of this study).
Project description:Bacteriophage (phage) are viruses that can kill bacteria, but also mediate gene transfer for bacterial evolution. The telomere phages are a curious form using telomere-like structures to replicate their genomes as linear extrachromosomal elements. Here we find that telomere phages are widely distributed in bacteria, being highly prevalent in Klebsiella species. We established a model system to investigate telomere phage biology and find only a small set of phage proteins are expressed in phage-host cells, including a toxin – telocin - that kills other Klebsiella strains. We identify and validate other telocins in the genomes of other, widespread Klebsiella telomere phages. Thus, telomere phages are widespread elements encoding diverse antibacterial weapons and we discuss the prospect of using telocins for precision editing of microbial populations.
Project description:The increasing antibiotic resistance of Klebsiella pneumoniae poses a serious threat to global public health. To investigate the antibiotic resistance mechanism of Klebsiella pneumonia, we performed gene expression profiling analysis using RNA-seq data for clinical isolates of Klebsiella pneumonia, KPN16 and ATCC13883. Our results showed that mutant strain KPN16 is likely to act against the antibiotics through increased increased butanoate metabolism and lipopolysaccharide biosynthesis, and decreased transmembrane transport activity.
Project description:The interactions between Gram-negative respiratory pathogens and the host environment at the site of infection largely unknown. Pulmonary surfactant serves as an initial point of contact for inhaled bacteria entering the lung and is thought to contain molecular cues that aid colonization and pathogenesis. To gain insight into this ecological transition, we characterized the transcriptional responses of Pseudomonas aeruginosa PA14, Burkholderia thailandensis E264, Klebsiella pneumoniae MGH 78578, and Stenotrophomonas maltophilia K279A exposed to purified pulmonary surfactant (Survanta) through microarrays. This study provides novel insight into the interactions occurring between Gram-negative opportunistic pathogens and the host at an important infection site, and demonstrates the utility of purified lung surfactant preparations for dissecting host-lung pathogen interactions in vitro. The goal of this study was to compare the transcriptional responses of Pseudomonas aeruginosa PA14, Burkholderia thailandensis E264, Klebsiella pneumoniae MGH 78578, and Stenotrophomonas maltophilia K279A exposed to pulmonary surfactant using a custom affymetrix chip designed for their genomes. The goal of this study was to compare the transcriptional responses of Pseudomonas aeruginosa PA14, Burkholderia thailandensis E264, Klebsiella pneumoniae MGH 78578, and Stenotrophomonas maltophilia K279A exposed to pulmonary surfactant using a custom affymetrix chip designed for their genomes.
Project description:Screening of 14 novel proteins derived from Klebsiella pneumoniae MGH 78578 identified prior via screening of cDNA libraries. The full-length proteins were attached using a specific HaloTag to their corresponding ligand surface, HaloLink. Screening was performed using two different polyclonal antibodies to Klebsiella pneumoniae (Acris AP00792PU-N and Abcam ab20947) and detection achieved by Goat polyclonal to rabbit IgG conjugated with Chromeo-546 (Abcam ab60317). In order to assess their potential immungenic nature and rank the proteins investigated, comparative analysis using already described antigens from K. pneumoniae were used in the assay. Each microarray was seperated into different incubation chambers using the 16-well ProPlate (Grace Biolabs) multi-well gaskets. As positive references ompA and mdh were used. For negative control gapA was used and the crude lysates of the expression host (Acella E.coli) and buffer were spotted as well.Samples and controls were spotted with five replicates each. Incubation was performed using different antibodies reactive to K. pneumoniae.