Proinflammatory cytokines in antilipopolysaccharide immunity against Klebsiella infections

A novel antivirulent compound fluorothiazinone inhibits Klebsiella pneumoniae biofilm in vitro and suppresses model pneumonia

The problematic treatment of infections caused by multiple-resistant Klebsiella, especially in ICU, is the leading cause of prolonged hospitalization and high mortality rates. The use of antibiotics for the prevention of infections is considered unreasonable as it may contribute to the selection of resistant bacteria. In this regard, the development of drugs that will be effective in preventing infection during various invasive procedures is extremely necessary. We have shown that the developed innovative antibacterial compound fluorothiazinone (FT) that suppresses the formation of biofilms is effective in the prevention of a model pneumonia caused by a multi-resistant clinical K. pneumoniae isolate. Prophylactic use followed by treatment with FT in mice with acute pneumonia modulates the local innate immune response without suppressing protective properties in the early stages of infection, while contributing to a decrease in the bacterial load in the organs and preventing lethal pathological changes in the lungs at later stages of K. pneumoniae infection. Further development of such antivirulence drugs and their use will reduce morbidity and mortality in nosocomial infections, as well as reduce the number of antibiotics used.

Active hexose correlated compound activates immune function to decrease bacterial load in a murine model of intramuscular infection

BACKGROUND

Infection is a serious, costly, and common complication of surgery and constitutes the principal cause of late death in patients undergoing surgery. The objective of this study was to clarify the mechanisms by which active hexose correlated compound (AHCC) increases survival in a murine model of intramuscular infection.

METHODS

Food-deprived mice receiving either AHCC or excipient were infected with bacteria. Kinetics of bacterial load, white blood cell counts, cytokine levels, and antibody levels were compared between groups.

RESULTS

AHCC-treated mice had reduced bacterial load at day 5 and cleared bacteria entirely at day 6. Levels of interleukin-12, tumor necrosis factor-alpha, and interleukin-6 peaked earlier in this group (day 3) compared with controls (day 5). Increased percentages of peripheral lymphocytes and monocytes and decreased numbers of polymorphonuclear cells were detected in the AHCC group.

CONCLUSIONS

AHCC appears to induce an early activation of the immune response, leading to an effective clearance of bacteria and rapid recovery.

IL-10 in antilipopolysaccharide immunity against systemic Klebsiella infections

AIM

This study was undertaken in order to determine whether anti-inflammatory cytokine interleukin-10 is responsible for a previously described protection against Klebsiella infection mediated by antilipopolysaccharide antibodies.

METHODS

BALB/c mice were infected intraperitoneally with a lethal challenge of Klebsiella pneumoniae Caroli. One group was protected with monoclonal antibodies prior to infection and the second was not. We measured plasma levels of interleukin-10 at different time points by enzyme immunoassay and analyzed the relation between interleukin-10 and proinflammatory cytokines interleukin-6 and tumor necrosis factor-alpha in order to determine the association of these ratios with the outcome of infection.

MAJOR FINDINGS AND CONCLUSIONS

We found different pattern of interleukin-10 production in protected mice compared with unprotected ones. The difference is greatest 24 hours postinfection. The ratios between IL-10 and proinflammatory cytokines confirmed the suppressed proinflammatory response in protected animals, especially 24 hours postinfection. Hence the mortality in unprotected mice begins immediately after we conclude that such cytokine relation and IL-10 production are, at least partially, responsible for the destiny of infected animals and the outcome of infection.