Journal: Nucleic Acids Research

Article Title: PhoP-regulated VirK acts as an accessory factor to maintain virulence in polymyxin-resistant Klebsiella pneumoniae

doi: 10.1093/nar/gkag290

Figure Lengend Snippet: Sequence and structure comparison of VirK (from K. pneumoniae ATCC BAA2146) and YbjX (from E. coli K-12 ) proteins. ( A ) Alignment of the amino acid sequence of VirK ( Q ) with that of YbjX ( T ); ( B ) Comparison of the protein structures of VirK and YbjX. Amino acid sequences and structures were compared using the foldseek server . The protein structure of YbjX was obtained from the AFDB database (AFDB accession: AF- P75829 -F1).

Article Snippet: Results from K. pneumoniae ATCC BAA2146 serial strains suggested that virK deficiency resulted in a modest reduction in bacterial virulence, while complementation partially restored this phenotype.

Techniques: Sequencing, Comparison

Journal: Vaccines

Article Title: Fine-Mapping and Protective Analysis of Immunodominant Linear B-Cell Epitopes of FimA Antigen of Klebsiella Pneumoniae

doi: 10.3390/vaccines14040347

Figure Lengend Snippet: Identification of B-cell immunodominant epitopes of FimA. To elucidate adjuvant-driven differences in FimA-specific immunity, we mapped immunodominant linear B-cell epitopes using antisera collected on day 7 after the final immunization from BALB/c mice immunized with FimA formulated with Al(OH) 3 . ( A ) Fine mapping of B-cell immunodominant epitopes of FimA. There were four positive peptides: FimA 97–114 , FimA 103–120 , FimA 109–126 , and FimA 145–160 , which showed significantly higher readings compared to other dominant peptides, indicating their dominance as epitopes. OVA 192–201 serves as a negative irrelevant peptide. ( B ) Localization of B-cell immunodominant epitopes of FimA in its three-dimensional structure. To explore the structural basis for the observed differences in immunodominance hierarchy and their correlation with protective efficacy, we mapped the four epitopes onto the crystal structure of FimA (PDB ID: 6JZK) using PyMOL1.1 software. The immunedominant peptides FimA 97–114 , FimA 103–120 , FimA 109–126 , and FimA 145–160 are located on the outer surface of the FimA three-dimensional crystal structure. Among them, FimA 97–114 , FimA 103–120, and FimA 109–126 were on the α-helical region of FimA, while FimA 145–160 was on the β-sheet structure of FimA. ( C ) Amino acid sequence conservation analysis of B-cell immunodominant epitopes of FimA. 30 randomly selected K. pneumoniae strains were obtained from the GenBank database. The regions shown in red represent amino acid sequence identity, and the amino acid sequences of these immunodominant peptides are highly conserved among 30 K. pneumoniae strains, with a sequence identity reaching 100%. (*, p < 0.05; **, p < 0.01; ***, p < 0.001).

Article Snippet: The standard K. pneumoniae strain (ATCC700721, TaxID: 272620) was purchased from the American Type Culture Collection.

Techniques: Adjuvant, Software, Sequencing

Journal: Vaccines

Article Title: Fine-Mapping and Protective Analysis of Immunodominant Linear B-Cell Epitopes of FimA Antigen of Klebsiella Pneumoniae

doi: 10.3390/vaccines14040347

Figure Lengend Snippet: Analysis of immunoprotective capability of immunodominant epitope peptides-KLH protein. To analyze the immunoprotective properties of immunodominant epitope peptides, the peptides were conjugated with the KLH protein. The mix-peptides-KLH includes FimA 97–114 -KLH, FimA 103–120 -KLH, FimA 109–126 -KLH and FimA 145–160 -KLH. Subsequently, BALB/c mice were immunized with the conjugated protein to assess the survival rate of actively immunized mice following ATCC700721 infection. ( A ) Survival rate of the immunized mice after ATCC700721 infection. Compared to the PBS + Al(OH) 3 group, the statistical analysis revealed the following differences in these epitope-KLH immunized groups: FimA 109–126 -KLH + Al(OH) 3 (****, p < 0.0001) , FimA 145–160 -KLH + Al(OH) 3 (****, p < 0.0001), and Mix-Peptides + Al(OH) 3 (****, p < 0.0001). ( B ) The amount of the K. pneumoniae in the immunized mice after ATCC700721 infection. Compared to the PBS + Al(OH) 3 group, the statistical analysis revealed the following differences in clearing the bacteria in the infected lung: FimA 109–126 -KLH + Al(OH) 3 (****, p < 0.0001) , FimA 145–160 -KLH + Al(OH) 3 (****, p < 0.0001), and Mix-Peptides + Al(OH) 3 (****, p < 0.0001). ( C ) The average levels of epitope-specific antibodies in the mice immunized with the single peptide-KLH or mixed peptides-KLH. ( D ) Reciprocal of serum dilution in the mice immunized with the single peptide-KLH or mixed peptides-KLH immunized mice. ( E ) The levels of each subtype of antibodies in the antisera of mice immunized with the single peptide-KLH or mixed peptides-KLH immunized mice. ( F ) Cytokine profiling analysis of the antisera in the mice immunized with the single peptide-KLH or mixed peptides-KLH immunized mice. One week after the final immunization, mice were challenged with a sublethal dose of ATCC700721, and the levels of proinflammatory cytokines in BALF were measured 48 h post-infection. Statistical significance was annotated using GraphPad Prism 8.0, and significance levels are indicated by asterisks above the bars in the bar graph. (*, p < 0.05; **, p < 0.01; ***, p < 0.001, ****, p < 0.0001).

Article Snippet: The standard K. pneumoniae strain (ATCC700721, TaxID: 272620) was purchased from the American Type Culture Collection.

Techniques: Infection, Bacteria

Journal: Vaccines

Article Title: Fine-Mapping and Protective Analysis of Immunodominant Linear B-Cell Epitopes of FimA Antigen of Klebsiella Pneumoniae

doi: 10.3390/vaccines14040347

Figure Lengend Snippet: Broad-spectrum immunoprotective analysis of mixed immunodominant peptides-KLH against clinical strains of K. pneumoniae . To assess the broad-spectrum immunoprotection of the mixed immunodominant peptides-KLH against clinical strains of K. pneumoniae , various clinical isolates were chosen based on MLST. One week after the final immunization, the mice were challenged with a lethal dose of the clinical isolates via tracheal intubation. Survival rate of the immunized mice after clinical isolate infections. Comparing with the corresponding control groups, Mix+Peptides-KLH showed a survival rate of 60% against clinical isolate 10CYZ ( A ), 50% against 13LGY ( B ), 50% against 19ZXQ ( C ), 40% against 22CZY ( D ). Compared with the PBS + Al(OH) 3 group, the statistical results of bacterial burden in the lungs of mice immunized with the mixed peptide + Al(OH) 3 following challenge with different strains are shown below: 10CYZ challenge group (**, p =0.0099), 13LGY (*, p = 0.0471), 19ZXQ (****, p < 0.0001), 22CYZ (**, p = 0.0051) ( E – H ).

Article Snippet: The standard K. pneumoniae strain (ATCC700721, TaxID: 272620) was purchased from the American Type Culture Collection.

Techniques: Control

Journal: Vaccines

Article Title: Fine-Mapping and Protective Analysis of Immunodominant Linear B-Cell Epitopes of FimA Antigen of Klebsiella Pneumoniae

doi: 10.3390/vaccines14040347

Figure Lengend Snippet: Analysis of immunodominant peptides of FimA antigen in clinical human convalescent sera after K. pneumoniae infection. In this experiment, serum samples from patients infected with K. pneumoniae were collected. ( A ) Reciprocal of FimA-specific antisera dilution of the human convalescent sera from K. pneumoniae infection. OVA 192–201 peptide-specific antisera were used as a negative control. ( B ) The mean titer of FimA-specific IgG antibodies in human sera was 1:14,720, which was significantly different from that of the OVA 192–201 peptide group (****, p < 0.0001). ( C ) The levels of each subtype of antibodies in the antisera of mice immunized with the single peptide-KLH or mixed peptides-KLH. ( D ) Fine mapping of B-cell immunodominant epitopes of FimA non-human convalescent sera after K. pneumoniae infection. The four novel immunodominant epitopes, including FimA 97–114 (*, p = 0.0257), FimA 103–120 (**, p = 0.0092), FimA 109–126 (**, p = 0.0084), and FimA 145–160 (****, p < 0.0001), identified in the FimA immunized mice were also found to be immunodominant in the human convalescent sera. ( E ) All overlapping peptides were used to map the linear B-cell epitopes recognized by human serum samples. In the antibody of human convalescent sera, there were also three other positive immunodominant epitopes, namely FimA 1–18 (**, p = 0.0087), FimA 49–60 (***, p = 0.0009), and FimA 55–72 (***, p = 0.0009).

Article Snippet: The standard K. pneumoniae strain (ATCC700721, TaxID: 272620) was purchased from the American Type Culture Collection.

Techniques: Infection, Negative Control

Journal: Current Issues in Molecular Biology

Article Title: In Vitro Evaluation of the Antimicrobial Activity of Origanum vulgare Essential Oil Against ESBL-Producing Strains of Escherichia coli and Klebsiella pneumoniae

doi: 10.3390/cimb48040373

Figure Lengend Snippet: Mueller–Hinton agar plates: ( a ) antibiogram of the E. coli 323 study strain; ( b ) antibiogram of the E. coli ATCC 25922 control strain; ( c ) antibiogram of the K. pneumoniae 132 study strain; ( d ) antibiogram of the K. pneumoniae ATCC 700603 control strain.

Article Snippet: In the case of the control strain K. pneumoniae ATCC 700603, the observed MIC was 1 μg/mL, which is within the QC ranges established by CLSI [ ] (0.25–2 μg/mL).

Techniques: Control

Journal: Current Issues in Molecular Biology

Article Title: In Vitro Evaluation of the Antimicrobial Activity of Origanum vulgare Essential Oil Against ESBL-Producing Strains of Escherichia coli and Klebsiella pneumoniae

doi: 10.3390/cimb48040373

Figure Lengend Snippet: Diagrams for the exploratory determination of the MIC of Origanum vulgare essential oil against: ( a ) E. coli 323; ( b ) E. coli ATCC 25922 control strain; ( c ) K. pneumoniae 132; ( d ) K. pneumoniae ATCC 700603 control strain. The central line represents the median, the box represents the interquartile range, and the individual points represent experimental replicates (n = 3). The vertical dashed line indicates the exploratory MIC, defined as the concentration associated with maximum inhibition.

Article Snippet: In the case of the control strain K. pneumoniae ATCC 700603, the observed MIC was 1 μg/mL, which is within the QC ranges established by CLSI [ ] (0.25–2 μg/mL).

Techniques: Control, Concentration Assay, Inhibition