concanavalin-a and Klebsiella-Infections

In the current scenario, frontline antibiotics are losing effectiveness against multidrug-resistant (MDR) bacteria because of the single mode of action. The accumulation of mutations and spread of antibiotic resistance markers among the bacteria results into the severe threat to community health. Now, there is an urgent requirement for the development of an alternate and as well as multiple-targeted action of drugs to stop the spread of resistance in bacteria. Here, we showed an alternative nanoparticle based photodynamic therapy (PDT) targeting the bacterial efflux pumps and its cell wall. The dextran capped gold nanoparticles (GNP

Topics: Biofilms; Carbonyl Cyanide m-Chlorophenyl Hydrazone; Concanavalin A; Drug Compounding; Drug Resistance, Multiple, Bacterial; Gold; Klebsiella Infections; Klebsiella pneumoniae; Membrane Transport Modulators; Metal Nanoparticles; Methylene Blue; Microbial Viability; Nanomedicine; Photochemotherapy; Photosensitizing Agents

Klebsiella pneumoniae is a healthcare-associated bacterial pathogen which causes severe diseases in immunocompromised individuals. Concanavalin A (conA), a lectin which recognizes proteins with mannose or glucose residues, has been reported to agglutinate K. pneumoniae and hence, is postulated to have therapeutical potential for K. pneumoniae-induced liver infection. This study investigated the conA binding properties of a large collection of clinical isolates of K. pneumoniae. ConA agglutination reaction was demonstrated by 94 (51.4%) of 183 K. pneumoniae isolates using a microtiter plate assay. The conA agglutination reactions were inhibited in the presence of 2.5 mg/ml D-mannose and 2.5 mg/ml glucose, and following pretreatment of the bacterial suspension with protease and heating at 80ºC. Majority of the positive isolates originated from respiratory specimens. Isolation of conA-binding proteins from K. pneumoniae ATCC 700603 strain was performed using conA affinity column and the conA binding property of the eluted proteins was confirmed by western blotting analysis using conA-HRP conjugates. Proteins with molecular weights ranging from 35 to 60 kDa were eluted from the conA affinity column, of which four were identified as outer membrane protein precursor A (37 kDa), outer membrane protein precursor C (40 kDa), enolase (45 kDa) and chaperonin (60 kDa) using mass spectrometry analysis. Several conA binding proteins (including 45 and 60 kDa) were found to be immunogenic when reacted with rabbit anti-Klebsiella antibody. The function and interplay of the conA binding proteins in bacterium-host cell relationship merits further investigation.

Topics: Agglutination; Agglutinins; Animals; Antibodies, Bacterial; Antigens, Bacterial; Bacterial Proteins; Blotting, Western; Chromatography, Affinity; Concanavalin A; Humans; Klebsiella Infections; Klebsiella pneumoniae; Mass Spectrometry; Molecular Weight; Protein Binding; Rabbits

Intragastric inoculation of Klebsiella pneumoniae can cause invasive diseases, including necrosis of liver tissues and bacteremia. The effect of concanavalin A (ConA) on K. pneumoniae was tested. Pretreatment with ConA was able to protect mice from K. pneumoniae infection in an intragastric model. K. pneumoniae-induced mouse death and liver injury such as liver necrosis, as well as blood levels of aspartate aminotransferase and alanine aminotransferase, were inhibited in a dose-dependent manner by ConA. ConA administered intravenously as late as 24 h after K. pneumoniae inoculation was still protective. In an in vitro assay, ConA was able to bind K. pneumoniae cells directly and further agglutinate them but had no effect on their in vitro growth. Surveys of bacterial counts of ConA-treated mice revealed that the bacteria were eliminated effectively in both blood and liver tissues. Furthermore, the bactericidal activity of macrophages against K. pneumoniae was also enhanced in a dose-dependent manner by ConA in an in vitro culture. These data suggest that ConA is a potentially therapeutic agent for K. pneumoniae-induced liver infection.

Topics: Alanine Transaminase; Animals; Aspartate Aminotransferases; Bacteremia; Concanavalin A; Immunohistochemistry; Immunologic Factors; Klebsiella Infections; Klebsiella pneumoniae; Liver; Macrophages; Mice; Mice, Inbred C57BL

The high morbidity after severe thermal insult is believed to be related partially to a resultant decrease in immunocompetence. We tested the ability of phytohemagglutinin (PHA) and Concanavalin (Con A) to stimulate lymphocyte transformation in 17 patients with moderate to severe thermal injury (greater than 25% BSA). The patients acted as their own controls and the per cent change in their mitogen response was measured over time. Eight acutely burned patients who subsequently developed severe sepsis (Group I) had decreased ability (mean, 12% of normal) to proliferate in response to PHA, and six of these died of severe sepsis. The depressed response appeared 4 to 7 days postinjury and predated clinical evidence of sepsis by 2 to 4 days. Cells from four patients who had mild infectious complications (Group II) demonstrated greatly augmented mitogen responses (mean + 243%) approximately 7 to 10 days postinjury. Five burn patients whose clinical course was sepsis free (Group III) exhibited only minimal changes in their mitogen responses (mean +30%). Although the Con A responses of the patients' cells corresponded less to their pathology, Group I patients whose cells exhibited depressed PHA responsiveness also had diminished Con A responses. Group II patients' cells also showed increases in Con A-induced stimulation. Group III patients, who had only slightly augmented PHA responses, had minimal decreases of the Con A-induced lymphocyte transformation. Many severely burned patients develop septicemia as a result of their large wound surfaces. The appearance of decreases in mitogen-induced proliferation, however, appears to characterize those patients who will be unable to handle the septic challenge.

Topics: Adult; Aged; Bacterial Infections; Burns; Concanavalin A; Escherichia coli Infections; Female; Humans; Immunocompetence; Klebsiella Infections; Lymphocyte Activation; Male; Middle Aged; Phytohemagglutinins; Prognosis; Pseudomonas Infections; Sepsis; Staphylococcal Infections; T-Lymphocytes; Time Factors