Tomislav Rukavina

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-α 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.

Binding to and Opsonophagocytic Activity of O-Antigen-Specific Monoclonal Antibodies against Encapsulated and Nonencapsulated Klebsiella pneumoniae Serotype O1 Strains

ABSTRACT The high mortality of nosocomial infections caused byKlebsiella spp. has acted as a stimulus to develop immunotherapeutic approaches targeted against surface molecules of these bacteria. Since O-antigen-specific antibodies may add to the protective effect of K antisera, we tested the functional and binding capacity of O-antigen-specific monoclonal antibodies (MAbs) raised against different Klebsiella O antigens. The MAbs tested were specific for the O-polysaccharide partial antigensd-galactan II (MAb Ru-O1), d-galactan I (MAb IV/4-5), or core oligosaccharide (MAb V/9-5) of theKlebsiella serogroup O1 antigen. In enzyme-linked immunosorbent assay binding experiments, we found that all MAbs recognized their epitopes on intact capsule-free bacteria; however, binding to encapsulated wild-type strains belonging to different K-antigen serotypes was significantly reduced. The K2 antigen acted as the strongest penetration barrier, while the K7 and K21 antigens allowed some, though diminished, antibody binding. In vitro phagocytic killing experiments showed that MAb Ru-O1 possessed significant opsonizing activity for nonencapsulated O1 serogroup strains and also, to a much lesser extent, for encapsulated strains belonging to the O1:K7 and O1:K21 serotypes. MAbs or antisera specific for thed-galactan II antigen may thus be the most promising agents for further efforts to develop a second-generationKlebsiella hyperimmune globulin comprising both K- and O-antigen specificities.

Proinflammatory Cytokines in Antilipopolysaccharide Immunity Against Klebsiella Infections

This study was undertaken in order to determine whether proinflammatory cytokines are involved in a previously described protection against Klebsiella infection mediated by antilipopolysaccharide antibodies. BALB/c mice were infected intraperitoneally with a lethal challenge of Klebsiella pneumoniae Caroli. One group of mice was protected with monoclonal antibodies against lipopolysaccharide prior to infection and the second was not. We determined the number of colony-forming units at different time points in the blood of infected animals and paralleled them with plasma levels of five proinflammatory cytokines measured by enzyme immunoassays. Our results show that the two groups of animals tested expressed different plasma concentrations for all cytokines. The greatest difference was detected 24 hours after infection, with a higher production in the unprotected group. We concluded that a reduced cytokine production is partially responsible for the survival of protected animals.

Microbiological and chemical indicators of water quality in indoor hotel swimming pools before and after training of swimming pool operators.

The present study was undertaken in order to determine the quality of indoor pool waters in hotels along the Croatian coast. We wanted to assess the risks of exposure to microbial and chemical contaminants and find out if training pool operators to use a quality assurance system, that we developed, influenced hygienic conditions and water quality in swimming pools or not. The samples were analysed for free chlorine, pH and several microbiological indicators according to standard laboratory methodologies. Of 1,329 samples tested, 276 were found to be unacceptable either by chemical (148) or microbiological parameters (128). After training, the proportion of unacceptable samples dropped by 23.5%, mostly according to the free chlorine values. According to our results, most of the microbiologically unacceptable samples had chlorine levels within the recommended range but their pH values were too high. A free chlorine level below 0.2 mg/L was found in 106 (82.8%) microbiologically unacceptable samples suggesting the need for maintaining the lower limit at least above 0.2 mg/L in order to reduce microbial risks to a more acceptable level. This measure combined with training of pool operators might result in reduced health risks in pool waters.

Evaluation design of Urban Health Centres Europe (UHCE): preventive integrated health and social care for community dwelling older persons in five European cities

BackgroundOlder persons often have interacting physical and social problems and complex care needs. An integrated care approach in the local context with collaborations between community-, social-, and health-focused organisations can contribute to the promotion of independent living and quality of life. In the Urban Health Centres Europe (UHCE) project, five European cities (Greater Manchester, United Kingdom; Pallini (in Greater Athens Area), Greece; Rijeka, Croatia; Rotterdam, the Netherlands; and Valencia, Spain) develop and implement a care template that integrates health and social care and includes a preventive approach. The UHCE project includes an effect and process evaluation.MethodsIn a one-year pre-post controlled trial, in each city 250 participants aged 75+ years are recruited to receive the UHCE approach and are compared with 250 participants who receive ‘care as usual’. Benefits of UHCE approach in terms of healthy life styles, fall risk, appropriate medication use, loneliness level and frailty, and in terms of level of independence and health-related quality of life and health care use are assessed. A multilevel modeling approach is used for the analyses. The process evaluation is used to provide insight into the reach of the target population, the extent to which elements of the UHCE approach are executed as planned and the satisfaction of the participants.DiscussionThe UHCE project will provide new insight into the feasibility and effectiveness of an integrated care approach for older persons in different European settings.Trial registrationISRCTN registry number is ISRCTN52788952. Date of registration is 13/03/2017.

The kinetics of IL-17 production in the lungs and plasma of mice after intratracheal infection with Klebsiella pneumoniae

BACKGROUND: Interleukin-17 is a proinflammatory cytokine predominantly produced by the T cells, which is involved in the innate immune responses to various physiologic and pathophysiologic processes including bacterial host defence. The neutralisation experiments showed that the lack of IL-17 leads to decreased neutrophil emigration and systemic granulopoietic responses to bacterial pathogens and allergens. The aim of our study was to determine the kinetics of IL-17 in plasma and lungs of animals intratracheally infected with Klebsiella pneumoniae. MATERIALS AND METHODS: In our experiments we used eight to twelve weeks old BALB/c male mice. Mice were intratracheally inoculated with 150 CFU of K. pneumoniae strain Caroli. At different time points mice were sacrificed and the lung and blood were aseptically removed and prepared for the cytokine determination. Cytokine determination was preformed by commercial ELISA kit (BenderMed Systems, Vienna, Austria). RESULTS: The IL-17 concentration in lung homogenates slightly increases in the first two hours of infection. Then it slightly decreases and again started to increase 24 hours after the infection. The concentration in lungs reached the maximal value 48 hours post infection. These results are consistent with data previously published by others. On the other hand, we also found increased plasma values of IL-17. Its concentration in plasma started to increase 12 hours after the infection and reaches the peak value 24 hours post infection. These results are in contrast with the results of others that reported no changes in systemic IL-17 production after the intratracheal K. pneumoniae challenge. CONCLUSIONS: The IL-17 in local host defences against Gram- negative pathogens is undoubtedly important for the clearance of microorganisms, but its importance in the systemic host response is still not resolved. Its maximal concentration in plasma correlates with the appearance of the bacteria in the blood after 24 hours, so we speculate that its role is to stimulate systemic proinflammatory cytokines to combat with a release of bacteria and/or their toxic products in the blood system.