Project description:The study aimed to characterize plasmids mediating carbepenem resistance in Klebsiella pneumoniae in Pretoria, South Africa. We analysed 56 K. pneumoniae isolates collected from academic hospital around Pretoria. Based on phenotypic and molecular results of these isolates, 6 representative isolates were chosen for further analysis using long reads sequencing platform. We observed multidrug resistant phenotype in all these isolates, including resistance to aminoglycosides, tetracycline, phenicol, fosfomycin, floroquinolones, and beta-lactams antibiotics. The blaOXA-48/181 and blaNDM-1/7 were manily the plasmid-mediated carbapenemases responsible for carbapenem resistance in the K. pneumoniae isolates in these academic hospitals. These carbapenemase genes were mainly associated with plasmid replicon groups IncF, IncL/M, IncA/C, and IncX3. This study showed plasmid-mediated carbapenemase spread of blaOXA and blaNDM genes mediated by conjugative plasmids in Pretoria hospitals.
Project description:To investigate the whole-genome gene expression difference between the wild-type and capsule deletion mutant in Klebsiella pneumoniae MGH 78578. The mutants analyzed in this study are further described in Huang T.W., Stapleton J.C., Chang H.Y., Tsai S.F., Palsson B.O., Charusanti P. Capsule removal via lambda-Red knockout system perturbs biofilm formation and fimbriae extression in Klesiella pneumoniae MGH 78578 (manuscript submission) A six chip study using total RNA recovered from three separate wild-type cultures and three separate cultures of a capsule deltion mutant of Klebsiella pneumoniae MGH 78578. The capsule gene cluster (KPN_02493 to KPN_02515) was entirely removed in the capsule deletion mutant. Each chip measures the expression level of 5,305 genes from Klebsiella pneumoniae MGH 78578 and the associated five plasmids (pKPN3, pKPN4, pKPN5, pKPN6 and pKPN7) with 50-mer oligo tiling array with 30-mer spacer.
Project description:The inappropriate use of antibiotics is a severe public health problem worldwide, contributing to the emergence of multidrug-resistant (MDR) bacteria. To explore the possible impacts of the inappropriate use of antibiotics on the immune system, we use Klebsiella pneumoniae (K. pneumoniae) infection as an example and show that imipenem increases the mortality of mice infected by MDR K. pneumoniae. Further studies demonstrate that imipenem enhances the secretion of outer membrane vesicles (OMVs) with significantly elevated presentation of GroEL, which promotes the phagocytosis of OMVs by macrophages that depends on the interaction between GroEL and its receptor LOX-1. OMVs cause the pyroptosis of macrophages and the release of proinflammatory cytokines, which contribute to exacerbated inflammatory responses. We propose that the inappropriate use of antibiotics in the cases of infection by MDR bacteria such as K. pneumoniae might cause damaging inflammatory responses, which underlines the pernicious effects of inappropriate use of antibiotic.
Project description:To investigate the whole-genome gene expression difference between the wild-type and capsule deletion mutant in Klebsiella pneumoniae MGH 78578. The mutants analyzed in this study are further described in Huang T.W., Stapleton J.C., Chang H.Y., Tsai S.F., Palsson B.O., Charusanti P. Capsule removal via lambda-Red knockout system perturbs biofilm formation and fimbriae extression in Klesiella pneumoniae MGH 78578 (manuscript submission)
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:Genome-wide gene expression analysis was performed with the cells in exponential and stationary growth phases. Through these two growth status, 89.6% of currently annotated genes were expressed. High-density oligonucleotide tiling arrays consisting of 379,528 50-mer probes spaced 30 bp apart across the whole Klebsiella pneumoniae MGH 78578 genome was used (Roche NimbleGen).
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:Investigation of whole genome gene expression level in Klebsiella pneumoniae MGH78578 grown up to mid-exponential phase in M9 minimal media supplemented with 0.2% glucose
