RESUMO
The increasing global occurrence of recalcitrant multi-drug resistant Klebsiella pneumoniae infections warrants the investigation of alternative therapy options, such as the use of monoclonal antibodies (mAbs). We used a target-agnostic phage display approach to K. pneumoniae bacteria lacking bulky, highly variable surface polysaccharides in order to isolate antibodies targeting conserved epitopes among clinically relevant strains. One antibody population contained a high proportion of unique carbohydrate binders, and biolayer interferometry revealed these antibodies bound to lipopolysaccharide (LPS). Antibodies that bound to O1 and O1/O2 LPS were identified. Antibodies were found to promote opsonophagocytic killing by human monocyte-derived macrophages and clearance of macrophage-associated bacteria when assessed using high-content imaging. One antibody, B39, was found to protect mice in a lethal model of K. pneumoniae pneumonia against both O1 and O2 strains when dosed therapeutically. High-content imaging, western blotting and fluorescence-activated cell sorting were used to determine binding to a collection of clinical K. pneumoniae O1 and O2 strains. The data suggests B39 binds to D-galactan-I and D-galactan-II of the LPS of O1 and O2 strains. Thus, we have discovered an mAb with novel binding and functional activity properties that is a promising candidate for development as a novel biotherapeutic for the treatment and prevention of K. pneumoniae infections.
Assuntos
Anticorpos Antibacterianos/imunologia , Epitopos/imunologia , Infecções por Klebsiella/imunologia , Klebsiella pneumoniae/imunologia , Lipopolissacarídeos/imunologia , Macrófagos/imunologia , Animais , Farmacorresistência Bacteriana Múltipla/genética , Farmacorresistência Bacteriana Múltipla/imunologia , Epitopos/genética , Humanos , Infecções por Klebsiella/genética , Klebsiella pneumoniae/genética , Lipopolissacarídeos/genética , Camundongos , OpsonizaçãoRESUMO
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
OBJECTIVE: To evaluate effects of Toll-like and nucleotide-binding oligomerization domain (NOD)-like receptor (TLR, NLR) ligand stimulation of equine mesenchymal stromal cells (MSCs) on antibacterial and immunomodulatory properties in vitro. STUDY DESIGN: Controlled laboratory study. SAMPLE POPULATION: Equine bone-marrow-derived MSCs (three horses). METHODS: MSCs were stimulated with TLR (polyinosinic:polycytidylic acid [pIC] and lipopolysaccharide [LPS]) and NLR agonists (γ-d-Glu-mDAP [IE-DAP]) for 2 h, and plated at 1 × 105 cells/well 24 h. MSC-conditioned media (MSC-CM) were collected and assessed for antimicrobial peptide cathelicidin/LL-37 production, bactericidal action against multidrug-resistant planktonic and biofilm Staphylococcus aureus and neutrophil phagocytosis. Bacterial growth was measured by plating bacteria and counting viable colonies, reading culture absorbance, and live-dead staining with confocal microscopy imaging. Following initial comparison of activating stimuli, TLR3-agonist pIC protocols (cell density during activation and plating, culture time, %serum) were further optimized for bactericidal activity and secretion of interleukin-8 (IL-8), monocyte-chemoattractant-protein (MCP-1), and cathelicidin/LL37. RESULTS: MSCs stimulation with pIC (p = .004) and IE-DAP (p = .03) promoted increased bactericidal activity, evidenced by reduced viable planktonic colony counts. PIC stimulation (2 × 106 cells/ml, 2 h, 10 µg/ml) further suppressed biofilm formation (p = .001), enhanced neutrophil bacterial phagocytosis (p = .009), increased MCP-1 secretion (p < .0001), and enhanced cathelicidin/LL-37 production, which was apparent when serum concentration in media was reduced to 1% (p = .01) and 2.5% (p = .05). CONCLUSION: TLR-3 pIC MSCs activation was most effective to enhance antibacterial and cytokine responses, which were affected by serum reduction. CLINICAL SIGNIFICANCE: In vitro TLR-3 activation of equine MSCs tested here may be a strategy to improve antibacterial properties of MSCs to treat antibiotic-resistant infections.
Assuntos
Peptídeos Catiônicos Antimicrobianos/biossíntese , Cavalos/imunologia , Imunomodulação/genética , Células-Tronco Mesenquimais/imunologia , Fagocitose/efeitos dos fármacos , Staphylococcus aureus/fisiologia , Receptores Toll-Like/metabolismo , Animais , Biofilmes , Citocinas/biossíntese , Farmacorresistência Bacteriana Múltipla/imunologia , Neutrófilos/efeitos dos fármacos , CatelicidinasRESUMO
Multidrug-resistant (MDR) endophthalmitis is a serious threat to the whole spectrum of therapeutic procedures associated with the risk of managing and preventing vision loss. We have earlier shown the interplay of immune mediators in patients with MDR Pseudomonas aeruginosa (PA) endophthalmitis leading to worse outcome. Expanding on these findings, a murine model of endophthalmitis was developed to explore the effects of drug resistance on the pathogenesis by analyzing the temporal changes in retinal morphology along with its transcriptomic signatures. Clinical isolates of susceptible (S-PA) and multidrug-resistant PA (MDR-PA) were injected intravitreally in C57BL/6 mice followed by enucleation at 6 and 24 h time points postinfection. Disease progression and retinal changes were monitored by clinical and histological assessment and transcriptome analysis in a pair-wise manner. Histological assessment of MDR-PA eyeball revealed higher disease severity (p < 0.05), CD45+ cells (p = 0.007), MPO+ cells (p = 0.01), GFAP+ (p = 0.02), along with higher retinal cell death in mice infected with MDR-PA (p = 0.008). Temporal transcriptome analysis revealed differential expression of nearly 923 genes at 6 h p.i. and 2,220 genes at 24 h p.i. (FC ≥2, adjusted p-value <0.05). Pathway enrichment analysis identified differential regulation of chemokine- and cytokine-mediated, MAPK, and NF-Ðºß signaling pathways. In conclusion, rapid deterioration of retinal architecture and immune exacerbation was significantly associated with the MDR endophthalmitis, suggesting the need for immunomodulatory agents to strengthen host cell functions and support antibiotics to save the retinal structure from inevitable deterioration and restoration of the vision.
Assuntos
Farmacorresistência Bacteriana Múltipla/imunologia , Endoftalmite/imunologia , Infecções por Pseudomonas/imunologia , Animais , Modelos Animais de Doenças , Endoftalmite/patologia , Feminino , Perfilação da Expressão Gênica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Infecções por Pseudomonas/patologia , Pseudomonas aeruginosaRESUMO
Antimicrobial resistance is a serious threat to global public health as antibiotics are losing effectiveness due to rapid development of resistance. The human immune system facilitates control and clearance of resistant bacterial populations during the course of antimicrobial therapy. Here we review current knowledge of mucosa-associated invariant T (MAIT) cells, an arm of the immune system on the border between innate and adaptive, and their critical place in human antibacterial immunity. We propose that MAIT cells play important roles against antimicrobial-resistant infections through their capacity to directly clear multidrug-resistant bacteria and overcome mechanisms of antimicrobial resistance. Finally, we discuss outstanding questions pertinent to the possible advancement of host-directed therapy as an alternative intervention strategy for antimicrobial-resistant bacterial infections.
Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/imunologia , Células T Invariantes Associadas à Mucosa/imunologia , Animais , Humanos , Imunidade nas Mucosas/imunologia , CamundongosRESUMO
Several explanations have been suggested concerning the variety in bacille Calmette-Guerin (BCG) vaccine efficacy on strains of Mycobacterium tuberculosis (Mtb). This study aimed to compare the effect of BCG vaccination history in the prevention of the occurrence of Mtb-Beijing and non-Beijing strains. In this cross-sectional study, 64 patients with pulmonary tuberculosis (TB) were recruited from the Iranian border provinces (North West and West). Isolates were subjected to restriction fragment length polymorphism (RFLP) analysis, using the insertion sequence IS6110 as a probe (IS6110 RFLP) and drug susceptibility testing using the proportion method. Samples were analyzed with Gel Compare II 6.6 and spss version 18. The mean age [standard deviation (SD)] of the patients was 54·4 (SD = 17·0). Overall, 49 cases (76·56%) had no BCG vaccination scar. The prevalence of Beijing strains was 9·38% and drug resistance proportion among the isolates was 14·1% (nine cases). There was a significant relationship between Beijing strains and tuberculosis (TB)-drug resistance in isolates (χ2 = 26·29, P < 0·001). There was also a strong association between vaccination history and Beijing strains (χ2 = 13·23, P = 0·002). Also, a statistical relationship was observed between Beijing strains and drug-resistant TB among patients with a history of vaccination (χ2 = 7·47, P = 0·002). This association was not maintained in the unvaccinated group (P = 0·102). These findings confirm the claim that the vaccine has different effects on different subspecies of tuberculosis. The cause of the high probability of drug resistance in patients with Beijing-TB and vaccination history requires further investigation with a higher sample size.
Assuntos
Vacina BCG/imunologia , Tuberculose Resistente a Múltiplos Medicamentos/imunologia , Tuberculose Pulmonar/imunologia , Estudos Transversais , Farmacorresistência Bacteriana Múltipla/imunologia , Feminino , Genótipo , Humanos , Irã (Geográfico) , Masculino , Testes de Sensibilidade Microbiana/métodos , Pessoa de Meia-Idade , Mycobacterium tuberculosis/imunologia , Polimorfismo de Fragmento de Restrição/imunologia , Vacinação/métodosRESUMO
Multi-drug resistant Vibrio vulnificus is a Gram-negative bacillus responsible for diseases, such as: sepsis, septicemia, gastroenteritis, and fatal necrotizing fasciitis in humans. The treatment and prevention of V. vulnificus infections are challenging because of resistance to antibiotics and the non-availability of a licensed vaccine. Considering this, an in-silico based approach comprising subtractive proteomics, immunoinformatics, molecular docking, and dynamics simulation studies is applied herein to identify potential epitope vaccine candidates for the mentioned pathogen. Two potential vaccine candidates: vibC and flgL are filtered based on essentiality, outer membrane localization, virulence, antigenic, pathway mapping, and cellular protein-protein network analysis. Using immunoinformatic tools, 9-mer B-cell derived T-cell antigenic epitopes are predicted for the said shortlisted two proteins that are demonstrating excellent affinity for predominant HLA allele (DRB1*0101) in human population. Screened peptides are used further in multi-epitope peptide designing and linked to an adjuvant to enhance the immunogenic properties of the designed construct. Furthermore, the construct was docked blindly to TLR4 immune receptor, and analyzed in conformational dynamics simulation to decipher the complex affinity and understand time dependent behavior, respectively. We expect this designed in silico construct to be useful for vaccinologists to evaluate its immune protective efficacy in in vivo animal models.
Assuntos
Farmacorresistência Bacteriana Múltipla/imunologia , Vacinas de Subunidades Antigênicas/imunologia , Vibrio vulnificus/imunologia , Antígenos de Bactérias/imunologia , Epitopos de Linfócito T/imunologia , Humanos , Simulação de Acoplamento Molecular/métodos , Simulação de Dinâmica Molecular , Proteômica , Receptor 4 Toll-Like/imunologia , Vibrioses/imunologiaRESUMO
The alarming escalation of infectious diseases resistant to conventional antibiotics requires urgent global actions, including the development of new therapeutics. Antimicrobial peptides (AMPs) represent potential alternatives in the treatment of multi-drug resistant (MDR) infections. Here, we focus on Cecropins (Cecs), a group of naturally occurring AMPs in insects, and on synthetic Cec-analogs. We describe their action mechanisms and antimicrobial activity against MDR bacteria and other pathogens. We report several data suggesting that Cec and Cec-analog peptides are promising antibacterial therapeutic candidates, including their low toxicity against mammalian cells, and anti-inflammatory activity. We highlight limitations linked to the use of peptides as therapeutics and discuss methods overcoming these constraints, particularly regarding the introduction of nanotechnologies. New formulations based on natural Cecs would allow the development of drugs active against Gram-negative bacteria, and those based on Cec-analogs would give rise to therapeutics effective against both Gram-positive and Gram-negative pathogens. Cecs and Cec-analogs might be also employed to coat biomaterials for medical devices as an approach to prevent biomaterial-associated infections. The cost of large-scale production is discussed in comparison with the economic and social burden resulting from the progressive diffusion of MDR infectious diseases.
Assuntos
Peptídeos Catiônicos Antimicrobianos , Farmacorresistência Bacteriana Múltipla , Bactérias Gram-Negativas/imunologia , Infecções por Bactérias Gram-Negativas , Proteínas de Insetos , Peptídeos Catiônicos Antimicrobianos/imunologia , Peptídeos Catiônicos Antimicrobianos/uso terapêutico , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/imunologia , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Infecções por Bactérias Gram-Negativas/imunologia , Humanos , Proteínas de Insetos/uso terapêuticoRESUMO
Nontuberculous mycobacteria (NTM) have recently emerged as important pathogens among cystic fibrosis (CF) patients worldwide. Mycobacterium abscessus is becoming the most worrisome NTM in this cohort of patients and recent findings clarified why this pathogen is so prone to this disease. M. abscessus drug therapy takes up to 2 years and its failure causes an accelerated lung function decline. The M. abscessus colonization of lung alveoli begins with smooth strains producing glycopeptidolipids and biofilm, whilst in the invasive infection, "rough" mutants are responsible for the production of trehalose dimycolate, and consequently, cording formation. Human-to-human M. abscessus transmission was demonstrated among geographically separated CF patients by whole-genome sequencing of clinical isolates worldwide. Using a M. abscessus infected CF zebrafish model, it was demonstrated that CFTR (cystic fibrosis transmembrane conductance regulator) dysfunction seems to have a specific role in the immune control of M. abscessus infections only. This pathogen is also intrinsically resistant to many drugs, thanks to its physiology and to the acquisition of new mechanisms of drug resistance. Few new compounds or drug formulations active against M. abscessus are present in preclinical and clinical development, but recently alternative strategies have been investigated, such as phage therapy and the use of ß-lactamase inhibitors.
Assuntos
Doenças Transmissíveis Emergentes , Fibrose Cística , Farmacorresistência Bacteriana Múltipla/imunologia , Infecções por Mycobacterium não Tuberculosas , Mycobacterium abscessus , Alvéolos Pulmonares , Animais , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/imunologia , Doenças Transmissíveis Emergentes/patologia , Fibrose Cística/epidemiologia , Fibrose Cística/imunologia , Fibrose Cística/patologia , Regulador de Condutância Transmembrana em Fibrose Cística/imunologia , Modelos Animais de Doenças , Humanos , Infecções por Mycobacterium não Tuberculosas/epidemiologia , Infecções por Mycobacterium não Tuberculosas/imunologia , Infecções por Mycobacterium não Tuberculosas/patologia , Mycobacterium abscessus/imunologia , Mycobacterium abscessus/patogenicidade , Alvéolos Pulmonares/imunologia , Alvéolos Pulmonares/microbiologia , Peixe-ZebraRESUMO
The widespread availability and use of modern synthetic therapeutic agents have led to a massive decline in ethnomedical therapies. However, these synthetic agents often possess toxicity leading to various adverse effects. For instance, anti-tubercular treatment (ATT) is toxic, lengthy, and severely impairs host immunity, resulting in posttreatment vulnerability to reinfection and reactivation of tuberculosis (TB). Incomplete ATT enhances the risk for the generation of multidrug- or extensively drug-resistant (MDR or XDR, respectively) variants of Mycobacterium tuberculosis (M. tb), the TB-causing microbe. Therefore, a new therapeutic approach that minimizes these risks is urgently needed to combat this deadly disease and prevent future TB epidemics. Previously, we have shown that the phytochemical bergenin induces T helper 1 (Th1)- and Th17 cell-based protective immune responses and potently inhibits mycobacterial growth in a murine model of M. tb infection, suggesting bergenin as a potential adjunct agent to TB therapy. Here, we combined ATT therapy with bergenin and found that this combination reduces immune impairment and the length of treatment in mice. We observed that co-treatment with the anti-TB drug isoniazid and bergenin produces additive effects and significantly reduces bacterial loads compared with isoniazid treatment alone. The bergenin co-treatment also reduced isoniazid-induced immune impairment; promoted long-lasting, antigen-specific central memory T cell responses; and acted as a self-propelled vaccine. Of note, bergenin treatment significantly reduced the bacterial burden of a multidrug-resistant TB strain. These observations suggest that bergenin is a potent immunomodulatory agent that could be further explored as a potential adjunct to TB therapy.
Assuntos
Benzopiranos/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Imunoterapia , Isoniazida/farmacologia , Mycobacterium tuberculosis/imunologia , Células Th1/imunologia , Células Th17/imunologia , Tuberculose Resistente a Múltiplos Medicamentos , Animais , Farmacorresistência Bacteriana Múltipla/imunologia , Camundongos , Células Th1/patologia , Células Th17/patologia , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/imunologia , Tuberculose Resistente a Múltiplos Medicamentos/patologiaRESUMO
IntroductionEmergence of resistance determinants of bla NDM and mcr-1 has undermined the antimicrobial effectiveness of the last line drugs carbapenems and colistin.AimThis work aimed to assess the prevalence of bla NDM and mcr-1 in E. coli strains collected from food in Shenzhen, China, during the period 2015 to 2017.MethodsMultidrug-resistant E. coli strains were isolated from food samples. Plasmids encoding mcr-1 or bla NDM genes were characterised and compared with plasmids found in clinical isolates.ResultsAmong 1,166 non-repeated cephalosporin-resistant E. coli strains isolated from 2,147 food samples, 390 and 42, respectively, were resistant to colistin and meropenem, with five strains being resistant to both agents. The rate of resistance to colistin increased significantly (p < 0.01) from 26% in 2015 to 46% in 2017, and that of meropenem resistance also increased sharply from 0.3% in 2015 to 17% in 2017 (p < 0.01). All meropenem-resistant strains carried a plasmid-borne bla NDM gene. Among the colistin-resistant strains, three types of mcr-1-bearing plasmids were determined. Plasmid sequencing indicated that these mcr-1 and bla NDM-bearing plasmids were structurally similar to those commonly recovered from clinical isolates. Interestingly, both mcr-1-bearing and bla NDM-bearing plasmids were transferrable to E. coli strain J53 under selection by meropenem, yet only mcr-1-bearing plasmids were transferrable under colistin selection.ConclusionThese findings might suggest that mobile elements harbouring mcr-1 and bla NDM have been acquired by animal strains and transmitted to our food products, highlighting a need to prevent a spike in the rate of drug resistant food-borne infections.
Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Colistina/uso terapêutico , Farmacorresistência Bacteriana Múltipla/genética , Infecções por Escherichia coli/tratamento farmacológico , Proteínas de Escherichia coli/genética , Escherichia coli/efeitos dos fármacos , Plasmídeos/imunologia , beta-Lactamases/genética , China/epidemiologia , Colistina/farmacologia , Farmacorresistência Bacteriana Múltipla/imunologia , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/microbiologia , Microbiologia de Alimentos , Humanos , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase , Prevalência , Análise de Sequência de DNARESUMO
Infections caused by New Delhi metallo-ß-lactamase (NDM)-producing strains of multidrug-resistant Klebsiella pneumoniae are a global public health threat lacking reliable therapies. NDM is impervious to all existing ß-lactamase inhibitor (BLI) drugs, including the non-ß-lactam BLI avibactam (AVI). Though lacking direct activity against NDMs, AVI can interact with penicillin-binding protein 2 in a manner that may influence cell wall dynamics. We found that exposure of NDM-1-producing K. pneumoniae to AVI led to striking bactericidal interactions with human cathelicidin antimicrobial peptide LL-37, a frontline component of host innate immunity. Moreover, AVI markedly sensitized NDM-1-producing K. pneumoniae to killing by freshly isolated human neutrophils, platelets, and serum when complement was active. Finally, AVI monotherapy reduced lung counts of NDM-1-producing K. pneumoniae in a murine pulmonary challenge model. AVI sensitizes NDM-1-producing K. pneumoniae to innate immune clearance in ways that are not appreciated by standard antibiotic testing and that merit further study.
Assuntos
Compostos Azabicíclicos/imunologia , Enterobacteriáceas Resistentes a Carbapenêmicos/imunologia , Imunidade Inata/imunologia , Infecções por Klebsiella/imunologia , Klebsiella pneumoniae/imunologia , beta-Lactamases/metabolismo , Animais , Antibacterianos/uso terapêutico , Compostos Azabicíclicos/uso terapêutico , Enterobacteriáceas Resistentes a Carbapenêmicos/metabolismo , Carbapenêmicos/farmacologia , Farmacorresistência Bacteriana Múltipla/imunologia , Feminino , Humanos , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Testes de Sensibilidade Microbiana/métodos , beta-Lactamases/imunologiaRESUMO
The emergence of clinical isolates associated to multidrug resistance is a serious threat worldwide in terms of public health since complicates the success of the antibiotic treatment and the resolution of the infectious process. This is of great concern in pathogens affecting the lower respiratory tract as these infections are one of the major causes of mortality in children and adults. In most cases where the respiratory pathogen is associated to multidrug-resistance, antimicrobial concentrations both in serum and at the site of infection may be insufficient and the resolution of the infection depends on the interaction of the invading pathogen with the host immune response. The outcome of these infections largely depends on the susceptibility of the pathogen to the antibiotic treatment, although the humoral and cellular immune responses also play an important role in this process. Hence, prophylactic measures or even immunotherapy are alternatives against these multi-resistant pathogens. In this sense, specific antibodies and antibiotics may act concomitantly against the respiratory pathogen. Alteration of cell surface structures by antimicrobial drugs even at sub-inhibitory concentrations might result in greater exposure of microbial ligands that are normally hidden or hardly exposed. This alteration of the bacterial envelope may stimulate opsonization by natural and/or specific antibodies or even by host defense components, increasing the recognition of the microbial pathogen by circulating phagocytes. In this review we will explain the most relevant studies, where vaccination or the use of monoclonal antibodies in combination with antimicrobial treatment has demonstrated to be an alternative strategy to overcome the impact of multidrug resistance in respiratory pathogens.
Assuntos
Antibacterianos/uso terapêutico , Anticorpos Antibacterianos/uso terapêutico , Infecções Bacterianas , Farmacorresistência Bacteriana Múltipla , Infecções Respiratórias , Animais , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/imunologia , Infecções Bacterianas/patologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/imunologia , Humanos , Infecções Respiratórias/tratamento farmacológico , Infecções Respiratórias/imunologia , Infecções Respiratórias/patologiaRESUMO
BACKGROUND: Multidrug resistant (MDR) bacterial pathogens are a serious problem of increasing importance facing the medical community. MDR bacteria typically infect the most immunologically vulnerable: patients in intensive care units, patients with extensive comorbidities, oncology patients, hemodialysis patients, and other immune suppressed individuals are likely to fall victim to these pathogens. One promising novel approach to treatment of MDR bacteria is immuno-adjuvant therapy to boost patient immunity. Success with this strategy would have the major benefit of providing protection against a number of MDR pathogens. OBJECTIVES: This study had two main objectives. First, immunophenotyping of peripheral blood mononuclear cells from patients with sepsis associated with MDR bacteria was performed to examine for findings indicative of immunosuppression. Second, the ability of three immuno-adjuvants with distinct mechanisms of action to reverse CD4 and CD8 T cell dysfunction, a pathophysiological hallmark of sepsis, was evaluated. RESULTS: Septic patients with MDR bacteria had increased expression of the inhibitory receptor PD-1 and its ligand PD-L1 and decreased monocyte HLA-DR expression compared to non-septic patients. All three immuno-adjuvants, IL-7, anti-PD-L1, and OX-40L, increased T cell production of IFN-γ in a subset of septic patients with MDR bacteria: IL-7 was most efficacious. There was a strong trend toward increased mortality in patients whose T cells failed to increase IFN-γ production in response to the three treatments. CONCLUSION: Immuno-adjuvant therapy reversed T cell dysfunction, a key pathophysiological mechanism in septic patients with MDR bacteria.
Assuntos
Antígeno B7-H1/administração & dosagem , Farmacorresistência Bacteriana Múltipla/imunologia , Interleucina-7/administração & dosagem , Receptores OX40/administração & dosagem , Sepse/imunologia , Sepse/microbiologia , Linfócitos T/imunologia , Adjuvantes Imunológicos/farmacologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Apresentação de Antígeno/efeitos dos fármacos , Apresentação de Antígeno/imunologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Feminino , Humanos , Interferon gama/metabolismo , Leucócitos/efeitos dos fármacos , Leucócitos/imunologia , Masculino , Pessoa de Meia-Idade , Monócitos/efeitos dos fármacos , Monócitos/imunologia , Ligante OX40/metabolismo , Receptor de Morte Celular Programada 1/metabolismo , Receptores de Interleucina-7/metabolismo , Sepse/sangue , Linfócitos T/efeitos dos fármacosRESUMO
Multidrug-resistant bacterial strains are a rapidly emerging healthcare threat; therefore it is critical to develop new therapies to combat these organisms. Prior antibacterial strategies directly target pathogen growth or viability. Host-directed strategies to increase antimicrobial defenses may be an effective alternative to antibiotics and reduce development of resistant strains. In this study, we demonstrated the efficacy of a pyrimidine synthesis inhibitor, N-phosphonacetyl-L-aspartate (PALA), to enhance clearance of methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Acinetobacter baumannii strains by primary human dermal fibroblasts in vitro. PALA did not have a direct bactericidal effect, but enhanced cellular secretion of the antimicrobial peptides human ß-defensin 2 (HBD2) and HBD3 from fibroblasts. When tested in porcine and human skin explant models, a topical PALA formulation was efficacious to enhance MRSA, P. aeruginosa, and A. baumannii clearance. Topical PALA treatment of human skin explants also resulted in increased HBD2 and cathelicidin (LL-37) production. The antimicrobial actions of PALA required expression of nucleotide-binding, oligomerization domain 2 (NOD2), receptor-interacting serine/threonine-protein kinase 2 (RIP2), and carbamoyl phosphatase synthase II/aspartate transcarbamylase/dihydroorotase (CAD). Our results indicate that PALA may be a new option to combat multidrug-resistant bacterial infections of the skin through enhancement of an integral pathway of the cutaneous innate immune defense system.
Assuntos
Ácido Aspártico/análogos & derivados , Bactérias/imunologia , Derme/imunologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Imunidade Inata/efeitos dos fármacos , Proteína Adaptadora de Sinalização NOD2/imunologia , Ácido Fosfonoacéticos/análogos & derivados , Pirimidinas/imunologia , Transdução de Sinais/efeitos dos fármacos , Dermatopatias Bacterianas/tratamento farmacológico , Animais , Ácido Aspártico/farmacologia , Bactérias/patogenicidade , Derme/microbiologia , Derme/patologia , Farmacorresistência Bacteriana Múltipla/imunologia , Células HEK293 , Humanos , Proteína Adaptadora de Sinalização NOD2/metabolismo , Ácido Fosfonoacéticos/farmacologia , Pirimidinas/biossíntese , Transdução de Sinais/imunologia , Dermatopatias Bacterianas/enzimologia , Dermatopatias Bacterianas/imunologia , Dermatopatias Bacterianas/microbiologia , SuínosRESUMO
Multidrug-resistant Gram-negative bacteria (MDR-GNB) are an emerging cause of morbidity and mortality after hematopoietic stem cell transplantation (HSCT). Three-hundred forty-eight consecutive patients transplanted at our hospital from July 2012 to January 2016 were screened for a pretransplant MDR-GNB colonization and evaluated for clinical outcomes. A pretransplant MDR-GNB colonization was found in 16.9% of allo-HSCT and in 9.6% of auto-HSCT recipients. Both in auto- and in allo-HSCT, carriers of a MDR-GNB showed no significant differences in overall survival (OS), transplant-related mortality (TRM), or infection-related mortality (IRM) compared with noncarriers. OS at 2 years for carriers compared with noncarriers was 85% versus 81% (P = .262) in auto-HSCT and 50% versus 43% (P = .091) in allo-HSCT. TRM at 2 years was 14% versus 5% (P = .405) in auto-HSCT and 31% versus 25% (P = .301) in allo-HSCT. IRM at 2 years was 14% versus 2% (P = .142) in auto-HSCT and 23% versus 14% (P = .304) in allo-HSCT. In multivariate analysis, only grade III to IV acute graft-versus-host disease was an independent factor for reduced OS (P < .001) and increased TRM (P < .001) and IRM (P < .001). During the first year after transplant, we collected 73 GNB bloodstream infectious (BSI) episodes in 54 patients, 42.4% of which sustained by a MDR-GNB. Rectal swabs positivity associated with the pathogen causing subsequent MDR-GNB BSI episodes in 13 of 31 (41.9%). Overall, OS at 4 months from MDR-GNB BSI episode onset was of 67.9%, with a 14-day attributed mortality of 12.9%, not being significantly different between carriers and noncarriers (P = .207). We conclude that in this extended single-center experience, a pretransplant MDR-GNB colonization did not significantly influence OS, TRM, and IRM both in auto- and allo-HSCT settings and that MDR-GNB attributed mortality can be controlled in carriers when an early pre-emptive antimicrobial therapy is started in case of neutropenic fever.
Assuntos
Bacteriemia/etiologia , Farmacorresistência Bacteriana Múltipla/imunologia , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Condicionamento Pré-Transplante/efeitos adversos , Transplante Autólogo/efeitos adversos , Transplante Homólogo/efeitos adversos , Adulto , Idoso , Bacteriemia/patologia , Feminino , Transplante de Células-Tronco Hematopoéticas/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Condicionamento Pré-Transplante/métodos , Transplante Autólogo/métodos , Transplante Homólogo/métodos , Adulto JovemRESUMO
The virulence of an isogenic pair of Pseudomonas aeruginosa strains was studied under similar experimental conditions in two animal infection models. The time to death was significantly longer for the multidrug resistant (MDR) than the wild-type strain. The transcriptional profiles of 84 innate immune response genes in the lungs of immune competent Balb/C mice were further compared. Significantly weaker expression of genes involved in production of soluble pattern recognition receptor and complement were observed in animals infected with the MDR strain. Altered patterns of innate immune system activation may explain the attenuated virulence in MDR bacteria.
Assuntos
Antibacterianos/imunologia , Suscetibilidade a Doenças/imunologia , Imunidade Inata/imunologia , Pulmão/imunologia , Infecções por Pseudomonas/imunologia , Pseudomonas aeruginosa/imunologia , Fatores de Transcrição/imunologia , Animais , Antibacterianos/farmacologia , Grupo dos Citocromos b/metabolismo , Modelos Animais de Doenças , Farmacorresistência Bacteriana Múltipla/imunologia , Feminino , Expressão Gênica , Larva/imunologia , Larva/microbiologia , Lepidópteros/imunologia , Lepidópteros/microbiologia , Pulmão/microbiologia , Pulmão/patologia , Camundongos , Camundongos Endogâmicos BALB C , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/patogenicidade , Fatores de Transcrição/genética , VirulênciaRESUMO
RATIONALE: The advent of extensively drug-resistant (XDR) tuberculosis (TB) and totally drug-resistant TB, with limited or no treatment options, has facilitated renewed interest in host-directed immunotherapy, particularly for therapeutically destitute patients. However, the selection and utility of such approaches depend on understanding the host immune response in XDR-TB, which hitherto remains unexplored. OBJECTIVES: To determine the host immunological profile in patients with XDR-TB, compared with drug-sensitive TB (DS-TB), using peripheral blood and explanted lung tissue. METHODS: Blood and explanted lung tissue were obtained from patients with XDR-TB (n = 31), DS-TB (n = 20), and presumed latent TB infection (n = 20). T-cell phenotype (T-helper cell type 1 [Th1]/Th2/Th17/regulatory T cells [Tregs]) was evaluated in all patient groups, and Treg function assessed in XDR-TB nonresponders by coculturing PPD-preprimed effector T cells with H37Rv-infected monocyte-derived macrophages, with or without autologous Tregs. Mycobacterial containment was evaluated by counting colony-forming units. MEASUREMENTS AND MAIN RESULTS: Patients failing XDR-TB treatment had an altered immunophenotype characterized by a substantial increase in the frequency (median; interquartile range) of CD4+CD25+FoxP3+ Tregs (11.5%; 5.9-15.2%) compared with DS-TB (3.4%; 1.6-5.73%; P < 0.001) and presumed latent TB infection (1.8%; 1.2-2.3%; P < 0.001), which was unrelated to disease duration. Tregs isolated from patients with XDR-TB suppressed T-cell proliferation (up to 90%) and subverted containment of H37Rv-infected monocyte-derived macrophages (by 30%; P = 0.03) by impairing effector T-cell function through a mechanism independent of direct cell-to-cell contact, IL-10, TGF (transforming growth factor)-ß, and CTLA-4 (cytotoxic T-lymphocyte-associated protein 4). CONCLUSIONS: Collectively, these data suggest that Tregs may be contributing to immune dysfunction, and bacterial persistence, in patients with XDR-TB. The relevant cellular pathways may serve as potential targets for immunotherapeutic intervention.
Assuntos
Antituberculosos/imunologia , Antituberculosos/uso terapêutico , Farmacorresistência Bacteriana Múltipla/imunologia , Tuberculose Extensivamente Resistente a Medicamentos/tratamento farmacológico , Tuberculose Extensivamente Resistente a Medicamentos/imunologia , Mycobacterium tuberculosis/imunologia , Linfócitos T Reguladores/imunologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Multidrug-resistant Acinetobacter baumannii, a common pathogen responsible for nosocomial infections, is the main cause for outbreaks of infectious diseases, such as pneumonia, meningitis, and bacteremia, especially among critically ill patients. Epidemic A. baumannii is a growing public health concern as it is resistant to all existing antimicrobial agents, thereby necessitating the development of new therapeutic approaches to mount an effective immune response against this bacterial pathogen. In this study, we identified a critical role for type I interferon (IFN) in epigenetic regulation during A. baumannii infection and established a central role for it in multiple cell death pathways. A. baumannii infection induced mixed cell death constituted of apoptosis, pyroptosis, and necroptosis. Mechanically, A. baumannii triggered TRIF-dependent type I IFN production, which in turn induced the expression of genes Zbp1, Mlkl, caspase-11, and Gsdmd via KAT2B-mediated and P300-mediated H3K27ac modification, leading to NLRP3 inflammasome activation, and potentially contributed to GSDMD-mediated pyroptosis and MLKL-dependent necroptosis. Our study offers novel insights into the mechanisms of type I IFN and provides potential therapeutic targets for infectious and inflammatory diseases.
Assuntos
Acinetobacter baumannii/imunologia , Farmacorresistência Bacteriana Múltipla/imunologia , Epigênese Genética , Interferon Tipo I/imunologia , Piroptose/imunologia , Acinetobacter baumannii/patogenicidade , Animais , Humanos , Interferon Tipo I/genética , Camundongos , Camundongos Knockout , Necrose , Piroptose/genéticaRESUMO
Neisseria gonorrhoeae is a significant health problem worldwide due to multi-drug resistance issues and absence of an effective vaccine. Patients infected with N. gonorrhoeae have not shown a better immune response in successive infections. This might be explained by the fact that N. gonorrhoeae possesses several mechanisms to evade the innate and adaptative immune responses at different levels. Macrophages are a key cellular component in the innate immune response against microorganisms. The current information suggests that gonococcus can hijack the host response by mechanisms that involve the control of macrophages activity. In this mini review, we intend to condense the recent knowledge on the macrophage-N. gonorrhoeae interactions with a focus on strategies developed by gonococcus to evade or to exploit immune response to establish a successful infection. Finally, we discuss the opportunities and challenges of therapeutics for controlling immune manipulation by N. gonorrhoeae.