Intraperitoneal Injection Of Bacteria Research Articles

Intranasal vaccination induces complete protection against multidrug resistant A. baumannii pneumonia and sepsis

Abstract In a WHO report released in Feb 2017, Acinetobacter baumannii has been list as top one of critical antibiotic-resistant “priority pathogens” which is in an urgent need for the new treatment. A. baumannii infections have become increasingly difficult to treat because most isolates are highly resistant to a wide range of antibiotics. With the absent of effective antibiotics, an effective vaccination regimen is urgently needed. We have established a pneumonia mouse model by non-invasive intratracheal instillation with A. baumannii and sepsis model by intraperitoneal injection of bacteria. Intranasal or intramascullar Vaccination both showed 100% protection against A. baumannii infection in pneumonia and sepsis model supported by reduced bacteria burderns, pathology, and reduced proinflammatory cytokine. Intranasal immunization also showed cross protection against different type clinical A. baumannii strains. A successful vaccine against A. baumannii will help us control its infection and overcome the development of multidrug resistance.

Interleukin-22 ameliorates acute-on-chronic liver failure by reprogramming impaired regeneration pathways in mice

Acute-on-chronic liver failure (ACLF) is a clinical syndrome defined by liver failure on pre-existing chronic liver disease. It is often associated with bacterial infection and high short-term mortality. Experimental models that fully reproduce ACLF are lacking, so too are effective pharmacological therapies for this condition. To mimic ACLF conditions, we developed a severe liverinjury model by combining chronic injury (chronic carbon tetrachloride [CCl4] injection), acute hepatic insult (injection of adouble dose of CCl4), and bacterial infection (intraperitoneal injection of bacteria). Serum and liver samples from patients with ACLF or acute drug-induced liver injury (DILI) were used. Liver injury and regeneration were assessed to ascertain the potential benefits of interleukin-22 (IL-22Fc) administration. This severe liver injury model recapitulated some of the key features of clinical ACLF, including acute-on-chronic liver injury, bacterial infection, multi-organ injury, and high mortality. Liver regeneration in this model was severely impaired because of a shift from the activation of the pro-regenerative IL-6/STAT3 pathway to the anti-regenerative IFN-γ/STAT1 pathway. The impaired IL-6/STAT3 activation was due to the inability of Kupffer cells to produce IL-6; whereas the enhanced STAT1 activation was due to a strong innate immune response and subsequent production of IFN-γ. Compared to patients with DILI, patients with ACLF had higher levels of IFN-γ but lower liver regeneration. IL-22Fc treatment improved survival in ACLF mice by reversing the STAT1/STAT3 pathway imbalance and enhancing expression of many antibacterial genes in a manner involving the anti-apoptotic protein BCL2. Acute-on-chronic liver injury or bacterial infection is associated with impaired liver regeneration due to a shift from a pro-regenerative to an anti-regenerative pathway. IL-22Fc therapy reverses this shift and attenuates bacterial infection, thus IL-22Fc may have therapeutic potential for ACLF treatment. A mouse model combining chronic liver injury, acute hepatic insult, and bacterial infection recapitulates some ofthe key features of acute-on-chronic liver failure (ACLF) in patients. Both fibrosis and bacterial infection contribute to theimpaired regenerative capacity of the liver in patients with ACLF. Herein, we show that IL-22Fc therapy improves ACLF by reprogramming impaired regenerative pathways and attenuating bacterial infection. Thus, it may have therapeutic potential for patients with ACLF.

Hepatocytes and neutrophils cooperatively suppress bacterial infection by differentially regulating lipocalin-2 and neutrophil extracellular traps.

Both hepatocytes and neutrophils combat bacterial infection through the production of LCN2; extracellular LCN2 secreted by hepatocytes limits systemic bacterial infection, whereas neutrophils carry LCN2 protein to the local site and against local bacterial infection through NETs. (Hepatology 2018).

The antimicrobial peptide hepcidin exerts an important role in the innate immunity against bacteria in the bony fish gilthead seabream

Antimicrobial peptides (AMPs) are important mediators of the immune response against bacteria and hepcidin is a 20–25 residues member with known functions in iron regulation and the innate immune response. Most studies have focused on mammalian organisms but very little is known about other vertebrate groups including teleost fish. Thus, based on the sequence of an EST database, we have characterized hepcidin gene organization, gene expression, distribution and in vitro and in vivo regulation, as well as the biological activity of a synthetic peptide in the teleost fish gilthead seabream ( Sparus aurata L.). First, it was found that the seabream hep gene genomic organization is formed by 3 exons and 2 introns, while the mRNA transcript is constitutively detected in most of the fish tissues but mainly in peritoneal leucocytes, head-kidney, liver and skin. Moreover, we have identified for the first time that hep is much more highly expressed in acidophilic granulocytes than in monocyte-macrophages and lymphocytes. In vitro, hep expression is up-regulated by several mitogens, pathogen-associated molecular patterns (PAMPs) and particulated antigens. Not surprisingly, intraperitoneal injection of bacteria or virus led to a significant gene up-regulation in the liver, head-kidney, peritoneal exudate or spleen. These observations suggest a major role for seabream hepcidin in the immune response to bacteria and viruses. Furthermore, the synthetic seabream Hep exerted an important antimicrobial activity against several bacterial strains in vitro reducing their viability. To conclude, seabream hep gene expression, up-regulation after in vitro or in vivo treatment with mitogens, PAMPs or particulated antigens and the direct in vitro biological activity against bacteria demonstrate that it is an important antimicrobial peptide and probably plays an important role in the innate immune response of fish.

A novel model of pneumonia from intraperitoneal injection of bacteria

Background Pneumonia remains a major clinical problem in the surgical patient. Experimental modeling by intratracheal injection of bacteria is not consistently reproducible. In an attempt to produce peritonitis by Klebsiella, we found evidence of pneumonia on autopsy and further developed this approach as a new experimental model. Methods Male Swiss Webster mice were given intraperitoneal (IP) injections of Klebsiella pneumoniae serotype 2 in different doses and this was compared with similar doses given intravenously (IV). A dose dependent survival curve was generated. Subsequently, 10 3 colony forming units (CFU) of bacteria were used in further experiments. Blood, peritoneal fluid and lung tissue were collected at time points up to 72 hours after injection and were cultured for levels of bacteria. Lung weights and myeloperoxidase levels were also measured. Results Intraperitoneal administration of Klebsiella was uniformly lethal with as few as 10 2 bacteria. Lung weight increased after IP Klebsiella, and all animals became bacteremic within 24 hours correlating with high bacterial levels in the lung. Conversely, most animals (72%) survived IV injection of bacteria, and were able to clear bacteria from the blood and lung. Conclusions We found that this model produced no clinically apparent peritonitis after 48 hours, but uniformly resulted in histopathologic changes of pneumonia by 24 hours. Survival time was related to initial dose of Klebsiella and there was a linear correlation between bacterial levels in the blood and lung. This model is reproducible, simple to perform, and the severity is easy to manipulate.

The professional phagocytes of sea bass (Dicentrarchus labrax L.): cytochemical characterisation of neutrophils and macrophages in the normal and inflamed peritoneal cavity

In order to identify the phagocytic cells of sea bass, the peritoneal leucocyte population of fish injected intraperitoneally with Photobacterium damselae subspecies piscicida was studied by light microscopy using cytocentrifuge preparations stained by the Antonow technique for peroxidase detection. Among the leucocytes present in the peritoneal exudate of the infected fish (macrophages, neutrophils, eosinophilic granular cells, lymphocytes and thrombocytes), macrophages and neutrophils were the only phagocytic cells. Neutrophils were easily distinguished from macrophages in Antonow stained preparations by the pattern of peroxidase positivity. Using ultrastructural cytochemistry, neutrophils were found to have abundant cytoplasmic granules positive for peroxidase and arylsulphatase and were negative for alpha-naphthyl butyrate (ANB) esterase. In contrast, ANB esterase activity was detected in macrophages. These leucocytes were typically negative for peroxidase, but ocasionally, some macrophages with peroxidase or arylsulphatase-positive vacuoles were observed. Both phagocytes had cytoplasmic granules positive for acid phosphatase. Glycogen particles were found in the cytoplasm of the two phagocytic cells, but they were much more abundant in neutrophils. Macrophages were much more abundant than neutrophils in the peritoneal cavity of non-injected sea bass but early after the intraperitoneal injection of bacteria, the number of neutrophils increased quickly and extensively. Higher numbers of intraperitoneally injected bacteria were found inside macrophages as compared to neutrophils because macrophages strongly predominated in the peritoneal population at the time of injection. However, when the bacteria were injected into peritoneal cavities with high numbers of neutrophils (attracted by a previous injection of 12% casein), the percentage of neutrophils with phagocytosed bacteria increased, approaching that of infected macrophages. Taken together, these results show that in sea bass, as in many other organisms, in addition to macrophages, neutrophils are important phagocytic cells, the relative participation of each of the two phagocytes in defense mechanisms against infection depending on the opportunity to encounter the invading infectious agents.

Spontaneous Tumor Cytolysis Mediated by Inflammatory Neutrophils: Dependence Upon Divalent Cations and Reduced Oxygen Intermediates

The role of divalent cations and reactive products of the respiratory burst were investigated in spontaneous tumor lysis mediated by inflammatory neutrophils (PMNs). Murine peritoneal PMNs, obtained five hours after intraperitoneal injection of bacteria, conjugated and lysed teratocarcinoma cells in chromium release and single-cell cytotoxicity assays. The presence of extracellular magnesium was required and was sufficient for tumor cell binding to PMNs. Postbinding lytic events depended upon the simultaneous presence of extracellular calcium and magnesium. Catalase and superoxide dismutase inhibited postbinding lytic events, indicating that production of reduced oxygen moieties was important. Scavengers of hydroxyl radicals could inhibit tumor cell binding, but none could affect postbinding lytic events. Neither could inhibitors of myeloperoxidase decrease tumor lysis. The ability of conjugating PMNs to lyse their bound targets correlated with their reduction of nitro blue tetrazolium (NBT). Optimal concentrations of phorbol myristate acetate (PMA) markedly increased the NBT positivity of PMNs and the killing of bound tumor cells. Even with optimal stimulation of the respiratory burst, however, there was still a significant number (19%) of bound targets that escaped lysis, suggesting active resistance to oxygen-mediated tumor cell injury.

Spontaneous tumor cytolysis mediated by inflammatory neutrophils: dependence upon divalent cations and reduced oxygen intermediates

The role of divalent cations and reactive products of the respiratory burst were investigated in spontaneous tumor lysis mediated by inflammatory neutrophils (PMNs). Murine peritoneal PMNs, obtained five hours after intraperitoneal injection of bacteria, conjugated and lysed teratocarcinoma cells in chromium release and single-cell cytotoxicity assays. The presence of extracellular magnesium was required and was sufficient for tumor cell binding to PMNs. Postbinding lytic events depended upon the simultaneous presence of extracellular calcium and magnesium. Catalase and superoxide dismutase inhibited postbinding lytic events, indicating that production of reduced oxygen moieties was important. Scavengers of hydroxyl radicals could inhibit tumor cell binding, but none could affect postbinding lytic events. Neither could inhibitors of myeloperoxidase decrease tumor lysis. The ability of conjugating PMNs to lyse their bound targets correlated with their reduction of nitro blue tetrazolium (NBT). Optimal concentrations of phorbol myristate acetate (PMA) markedly increased the NBT positivity of PMNs and the killing of bound tumor cells. Even with optimal stimulation of the respiratory burst, however, there was still a significant number (19%) of bound targets that escaped lysis, suggesting active resistance to oxygen-mediated tumor cell injury.

Protection from infection with Haemophilus influenzae type b by monoclonal antibody to the capsule.

Monoclonal antibodies to Haemophilus influenzae type b were produced by fusing splenic lymphocytes from immunized C57BL/6 mice with the mouse myeloma line P3-X63-Ag8.653. The antibody produced by one hybridoma (5M1H9) bound the capsular polysaccharide, as determined by a radiolabeled antigen-binding assay. The antibody was of the IgM class and was bactericidal in vitro with complement. The protective and therapeutic capacity of antibody 5M1H9 was examined in the infant rat model of H. influenzae type b disease. Antibody (0.1 ml), either undiluted or diluted 1:2, 1:10, or 1:100, administered 4 hr before intraperitoneal injection of 10(4)-10(5) H. influenzae type b organisms protected 100%, 90%,. 55% and 10% of the animals, respectively. To determine the efficacy of antibody 5M1H9 in treating established infection, antibody was given at 24-hr intervals after intraperitoneal injection of bacteria. Delayed administration of antibody 5M1H9 was effective in reducing both the level and incidence of bacteremia.

Secretory IgM, lysozyme and lymphocytes in the skin mucus of the channel catfish, Ictalurus punctatus

Channel catfish ( Ictalurus punctatus) skin mucus demonstrated an immunological response. Agglutinating antibody and bactericidal activity to Salmonella paratyphi were found in the mucus after intraperitoneal injection of bacteria. By immunodiffusion in gel, catfish skin mucus gave a precipitin line of identity with catfish 14S serum macroglobulin against rabbit anti-catfish 14S serum indicating the presence of secretory IgM in the mucus. Parenteral immunization (intraperitoneally) can thus yield specific IgM antibody in the mucus. Lysozyme was also demonstrated in the mucus as well as lymphocytes.

Bacterial ribonucleic acid synthesis in frog organs after intraperitoneal injection of bacteria.

Bacterial ribonucleic acid synthesis in frog organs after intraperitoneal injection of bacteria.

Bacterial RNA synthesis in frog auricles after intraperitoneal injection of bacteria

Des organes de plantes ou d'animaux mis dans une suspension bacterienne synthetisent du RNA bacterien. Ce phenomene que nous avons appele “transcession” est du au transfert de DNA spontanement cede par les bacteries vivantes aux cellules des organismes superieurs. Dans le present travail, il est demontre que le meme phenomene peut avoir lieu naturellement lorsqu'une grenouille est sujette a une infection bacterienne.

STUDIES ON PERITONITIS

Attempts have been made to produce experimental peritonitis by the intraperitoneal injection of bacteria into rabbits (Wegner, 1 Benians 2 and others) and into dogs (Noetzel 3 ). The results have been conflicting, some investigators reporting rapid death; others, survival of the animals. The discrepancy is probably due to the variability in the numbers, type and pathogenicity of the organisms used as well as to the nature of the fluid employed in the suspension of the bacteria. Later work has shown that the intraperitoneal injection of relatively large quantities of broth cultures of virulent Bacillus coli will kill rabbits quickly without inducing severe peritoneal reaction (Steinberg and Ecker 4 ). The same applies to guinea-pigs and to rats (unpublished experiments—Steinberg). This study was undertaken to determine the conditions necessary for the production of fatal peritonitis in the dog by the intraperitoneal injection of bacteria. EXPERIMENTAL WORK The micro-organism used in this investigation was a strain of