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:Bacterial persister cells are phenotypic variants of regular cells that are tolerant to antibiotics. Analysis of clinical isolates of M. tuberculosis showed that strains vary substantially in their tolerance to antibiotics. The level of persisters was very high is some isolates, suggesting that these are hip mutants. We investigated gene expression differences in eight clinical isolates, four of which we characterized as high-persister strains and four as low-persister, or regular, strains. Comparison of gene expression patterns may provide clues as to the genetic mechanisms underlying persister formation.
Project description:Precise definition of porin profiles is of critical importance to understand the role of porins in antimicrobial resistance. In this study, the outer membrane proteins (OMP) profiles of 26 clinical isolates of Klebsiella pneumoniae and of strain ATCC 13883 (wild-type) and ATCC 700603 (producing SHV-18) have been determined using both sodium-dodecyl-sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted laser desorption/ionization–time of flight/mass spectrometry (MALDI-TOF/MS). SDS-PAGE was performed using both homemade and commercial gels, and protein bands were identified by liquid chromatography coupled to mass spectrometry. A rapid extraction method was used to analyse OMPs by MALDI-TOF/MS. The sequences of porin genes were obtained by whole genome sequencing (WGS) and mutations were defined by BLAST. Same results were obtained for all strains either using SDS-PAGE or MALDI-TOF/MS. SDS-PAGE showed protein bands of ~35, ~36, and ~37 KDa, identified as OmpA, OmpK36 and OmpK35, respectively. By MALDI-TOF/MS, peaks at ~35700 (OmpA), ~37000 (OmpK35), and ~38000 (OmpK36) m/z were detected. ompK35 was intact in nine wild-type isolates and was truncated in 13 isolates, but OmpK35 was not observed in 3 isolates without mutations in ompK35. One point mutation was detected in another isolate and multiple mutations were detected in the remaining isolate. ompK36 was truncated in two isolates lacking this protein and presented one point mutation (n=1) or multiple mutations in the remaining isolates. In conclusion, MALDI-TOF/MS was reliable for porin detection, but because of the complex regulation of porin genes, WGS cannot always anticipate protein expression, as observed with SDS-PAGE and MALDI-TOF/MS.
Project description:The emergence of multidrug-resistant (MDR) Klebsiella pneumoniae represents a major public health concern, primarily driven by its ability to evade a wide range of antibiotics. Despite extensive genomic studies, proteomic insights into antibiotic resistance mechanisms remain scarce. Here, we employed a data-independent acquisition (DIA)-based quantitative proteomics approach to investigate proteomic differences between 87 MDR and 20 antibiotic-sensitive K. pneumoniae clinical isolates. A total of 3,380 proteins were identified, with 896 showing significant differential expression. MDR isolates exhibited increased expression of efflux pumps, beta-lactamases, and transcriptional regulators, while proteins associated with glycerolipid metabolism and transport were enriched in sensitive strains. To validate our findings, an independent cohort of 10 MDR and 11 sensitive isolates was analyzed. Key biomarkers identified in the discovery cohort, including pyruvate decarboxylase and aldehyde dehydrogenase, were validated with high discriminatory power (AUC > 0.85) in the validation cohort. These findings provide novel insights into the molecular mechanisms of antibiotic resistance and identify promising biomarkers for diagnosing MDR K. pneumoniae, offering potential avenues for therapeutic intervention.
