RESUMO
Extremely drug-resistant (XDR) Acinetobacter baumannii is a notorious and frequently encountered pathogen demanding novel therapeutic interventions. An initial monoclonal antibody (MAb), C8, raised against A. baumannii capsule, proved a highly effective treatment against a minority of clinical isolates. To overcome this limitation, we broadened coverage by developing a second antibody for use in a combination regimen. We sought to develop an additional anti-A. baumannii MAb through hybridoma technology by immunizing mice with sublethal inocula of virulent, XDR clinical isolates not bound by MAb C8. We identified a new antibacterial MAb, 65, which bound to strains in a pattern distinct from and complementary to that of MAb C8. MAb 65 enhanced macrophage opsonophagocytosis of targeted strains and markedly improved survival in lethal bacteremic sepsis and aspiration pneumonia murine models of A. baumannii infection. MAb 65 was also synergistic with colistin, substantially enhancing protection compared to monotherapy. Treatment with MAb 65 significantly reduced blood bacterial density, ameliorated cytokine production (interleukin-1ß [IL-1ß], IL-6, IL-10, and tumor necrosis factor), and sepsis biomarkers. We describe a novel MAb targeting A. baumannii that broadens immunotherapeutic strain coverage, is highly potent and effective, and synergistically improves outcomes in combination with antibiotics.
Assuntos
Infecções por Acinetobacter/imunologia , Acinetobacter baumannii/imunologia , Anticorpos Monoclonais/imunologia , Infecções por Acinetobacter/sangue , Infecções por Acinetobacter/microbiologia , Animais , Antibacterianos/imunologia , Anticorpos Antibacterianos/imunologia , Biomarcadores/sangue , Colistina/imunologia , Citocinas/sangue , Citocinas/imunologia , Farmacorresistência Bacteriana Múltipla/imunologia , Camundongos , Testes de Sensibilidade Microbiana/métodos , Sepse/sangue , Sepse/imunologia , Sepse/microbiologiaRESUMO
Sepsis is caused by organ dysfunction initiated by an unrestrained host immune response to infection. The emergence of antibiotic-resistant bacteria has rapidly increased in the last decades and has stimulated a firm research platform to combat infections caused by antibiotic-resistant bacteria that cannot be eradicated with conventional antibiotics. Strategies like epigenetic regulators such as lysine demethylase (Kdm) has received attention as a new target. Thus, we sought to investigate the epigenetic mechanisms in sepsis pathophysiology with the aim of discovering new concepts for treatment. A transcriptome analysis of dendritic cells during their inflammatory state identified Kdm as a critical molecule in sepsis regulation. Next, 8-hydroxyquinoline-5-carboxylic acid (IOX1) ability to control endotoxemia induced by Lipopolysaccharide and bacterial sepsis was demonstrated. IOX1 has been shown to regulate endotoxemia and sepsis caused by Escherichia coli and carbapenem-resistant Acinetobacter baumannii and has also contributed to the suppression of multidrug-resistant bacterial growth through the inhibition of DNA Gyrase. These findings show that IOX1 could be a component agent against bacterial sepsis by functioning as a broad-spectrum antibiotic with dual effects.
Assuntos
Infecções por Acinetobacter/tratamento farmacológico , Antibacterianos/farmacologia , Infecções por Escherichia coli/tratamento farmacológico , Hidroxiquinolinas/farmacologia , Sepse/tratamento farmacológico , Infecções por Acinetobacter/imunologia , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Animais , Antibacterianos/uso terapêutico , DNA Girase/metabolismo , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Modelos Animais de Doenças , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Infecções por Escherichia coli/imunologia , Infecções por Escherichia coli/microbiologia , Feminino , Histona Desmetilases/antagonistas & inibidores , Histona Desmetilases/metabolismo , Humanos , Hidroxiquinolinas/uso terapêutico , Camundongos , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Sepse/imunologia , Sepse/microbiologiaRESUMO
Lactoperoxidase (Lpo) and Lactoferrin (Lf) were extracted from camel colostrum milk and purified. The antibacterial activity of the two purified proteins was estimated against 14 isolates of multidrug resistance Acinetobacter baumannii. A combination of Lpo and Lf exhibited bactericidal action against A. baumannii in vitro. A mouse model of acute A. baumannii pneumonia was improved. The injection of combined Lpo and Lf after infection leads to significant clearance of A. baumannii rates in lung as well as blood culture P < 0.05 in comparing with control. Furthermore, the results showed a significant P < 0.05 reduction in the Bronchoalveolar lavage albumin concentration, lung injury and lactate dehydrogenase activity in comparing with control. In addition, the combination of Lpo and Lf treatment induced substantial elevation of IL-4 and IL10 concentrations p < 0.0 5 that helped to prevent damage caused by the inflammatory response. We concluded that combination of Lpo and Lf had a major inhibition effect against A. baumannii in comparing with imipenem as well as their immunomodulatory activity against resistant A. baumannii was increased by a synergistic effect of them as a crude combination. This study indicated two combined proteins consider as crucial strategy for practical treatment of pneumonia in the future.
Assuntos
Infecções por Acinetobacter/tratamento farmacológico , Infecções por Acinetobacter/imunologia , Acinetobacter baumannii/efeitos dos fármacos , Antibacterianos/administração & dosagem , Colostro/química , Fatores Imunológicos/administração & dosagem , Lactoferrina/administração & dosagem , Lactoperoxidase/administração & dosagem , Infecções por Acinetobacter/genética , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/fisiologia , Animais , Antibacterianos/isolamento & purificação , Camelus , Colostro/enzimologia , Farmacorresistência Bacteriana Múltipla , Sinergismo Farmacológico , Feminino , Humanos , Fatores Imunológicos/isolamento & purificação , Interleucina-10/genética , Interleucina-10/imunologia , Interleucina-4/genética , Interleucina-4/imunologia , Lactoferrina/isolamento & purificação , Lactoperoxidase/isolamento & purificação , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade MicrobianaRESUMO
Acinetobacter baumannii is a major cause of healthcare-associated infections worldwide with high morbidity and mortality. The clinical treatment of A. baumannii infections has become increasingly difficult because of the rapid emerging of multidrug and extremely drug resistant strains. Thus, there is an urgent need for the development of novel intervention strategies to combat this multidrug-resistant pathogen. Vaccine is one of the most effective medical measures for infection control and is likely to overcome the development of multidrug resistance by A. baumannii. Here we discussed the recent advances and potential challenges in development of A. baumannii vaccines with a focus on the 3 most important steps in the preclinical vaccine development: antigen selection, immune correlates of protection, and animal models for efficacy evaluation.
Assuntos
Infecções por Acinetobacter/prevenção & controle , Acinetobacter baumannii/imunologia , Vacinas Bacterianas/imunologia , Vacinas Bacterianas/isolamento & purificação , Descoberta de Drogas/métodos , Infecções por Acinetobacter/imunologia , Animais , Modelos Animais de Doenças , Descoberta de Drogas/tendências , Avaliação Pré-Clínica de Medicamentos/métodos , Humanos , CamundongosRESUMO
After growth in an iron-depleted chemically-defined medium Acinetobacter calcoaceticus expressed four high mol. wt outer-membrane proteins (OMPs) which were repressed under iron supplementation or in a complex laboratory medium. Immunoblotting with serum from a septicaemic patient infected with A. calcoaceticus revealed antibody binding to these iron-repressible OMPs, indicating that they were expressed in vivo, and also to the 42- and 18-Kda OMPs. Although the antibody response to the OMPs did not vary significantly during convalescence, the response to the O-polysaccharide component of lipopolysaccharide decreased significantly. However, antibodies in serum from patients with A. calcoaceticus wound infections reacted with the iron repressible OMPs and a 54-Kda antigen suggesting a difference in immune recognition between local and systemic infection.