RESUMO
Combination therapy with a beta-lactam plus an aminoglycoside has been the standard approach for treating febrile neutropenia for many years. More recently, beta-lactam monotherapy has also been shown to be a reliable and safe approach. In the present study, 763 eligible patients with fever and neutropenia received piperacillin-tazobactam monotherapy. On day 3, according to the study protocol, 165 patients with persistent fever who fulfilled the study entry criteria were randomised to receive vancomycin or a placebo. The success rate was 51% in the intention-to-treat analysis and 62% in the per-protocol analysis. The overall mortality rate was 8% (58/763), with only 18 (2.4%) deaths attributed to the initial or subsequent infection. Randomisation had no influence on the study endpoints. The adverse event rate was evaluated only in the patient population not included in the randomised part of the study. Among these patients, adverse events probably or definitely related to piperacillin-tazobactam therapy were uncommon, confirming the favourable safety profile of piperacillin-tazobactam. It was concluded that piperacillin-tazobactam could be considered as monotherapy for patients with high-risk febrile neutropenia.
Assuntos
Antibacterianos/uso terapêutico , Inibidores Enzimáticos/uso terapêutico , Febre/tratamento farmacológico , Neoplasias Hematológicas/complicações , Neutropenia/tratamento farmacológico , Ácido Penicilânico/análogos & derivados , Piperacilina/uso terapêutico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/administração & dosagem , Criança , Pré-Escolar , Inibidores Enzimáticos/administração & dosagem , Europa (Continente) , Febre/etiologia , Humanos , Lactente , Injeções Intravenosas , Pessoa de Meia-Idade , Oriente Médio , Neutropenia/etiologia , América do Norte , Ácido Penicilânico/administração & dosagem , Ácido Penicilânico/uso terapêutico , Piperacilina/administração & dosagem , Tazobactam , Resultado do TratamentoAssuntos
Infecções Bacterianas/tratamento farmacológico , Infecção Hospitalar/tratamento farmacológico , Gerenciamento Clínico , Pneumonia/tratamento farmacológico , Antibacterianos/uso terapêutico , Infecção Hospitalar/etiologia , Farmacorresistência Bacteriana , Humanos , Neutropenia/complicações , Respiração Artificial/efeitos adversosRESUMO
In a randomized, evaluator-blind, multicenter trial, we compared cefepime (2 g three times a day) with imipenem-cilastatin (500 mg four times a day) for the treatment of nosocomial pneumonia in 281 intensive care unit patients from 13 centers in six European countries. Of 209 patients eligible for per-protocol analysis of efficacy, favorable clinical responses were achieved in 76 of 108 (70%) patients treated with cefepime and 75 of 101 (74%) patients treated with imipenem-cilastatin. The 95% confidence interval (CI) for the difference between these response rates (-16 to 8%) failed to exclude the predefined lower limit for noninferiority of -15%. In addition, therapy of pneumonia caused by an organism producing an extended-spectrum beta-lactamase (ESBL) failed in 4 of 13 patients in the cefepime group but in none of 10 patients in the imipenem group. However, the clinical efficacies of both treatments appeared to be similar in a secondary intent-to-treat analysis (95% CI for difference, -9 to 14%) and a multivariate analysis (95% CI for odds ratio, 0.47 to 1.75). Furthermore, the all-cause 30-day mortality rates were 28 of 108 (26%) patients in the cefepime group and 19 of 101 (19%) patients in the imipenem group (P = 0.25). Rates of documented or presumed microbiological eradication of the causative organism were similar with cefepime (61%) and imipenem-cilastatin (54%) (95% CI, -23 to 8%). Primary or secondary resistance of Pseudomonas aeruginosa was detected in 19% of the patients treated with cefepime and 44% of the patients treated with imipenem-cilastatin (P = 0.05). Adverse events were reported in 71 of 138 (51%) and 62 of 141 (44%) patients eligible for safety analysis in the cefepime and imipenem groups, respectively (P = 0.23). Although the primary end point for this study does not exclude the possibility that cefepime was inferior to imipenem, some secondary analyses showed that the two regimens had comparable clinical and microbiological efficacies. Cefepime appeared to be less active against organisms producing an ESBL, but primary and secondary resistance to imipenem was more common for P. aeruginosa. Selection of a single agent for therapy of nosocomial pneumonia should be guided by local resistance patterns.
Assuntos
Cefalosporinas/uso terapêutico , Cilastatina/uso terapêutico , Infecção Hospitalar/tratamento farmacológico , Imipenem/uso terapêutico , Pneumonia Pneumocócica/tratamento farmacológico , Inibidores de Proteases/uso terapêutico , Tienamicinas/uso terapêutico , APACHE , Adulto , Idoso , Cefepima , Cefalosporinas/efeitos adversos , Cilastatina/efeitos adversos , Cuidados Críticos , Infecção Hospitalar/microbiologia , Método Duplo-Cego , Quimioterapia Combinada , Determinação de Ponto Final , Feminino , Humanos , Imipenem/efeitos adversos , Masculino , Pessoa de Meia-Idade , Pneumonia Pneumocócica/microbiologia , Estudos Prospectivos , Inibidores de Proteases/efeitos adversos , Respiração Artificial , Tienamicinas/efeitos adversosRESUMO
This prospective, double-blind trial assessed whether the addition of a glycopeptide would be able to reduce the time to defervescence in neutropenic patients with cancer who had persistent fever 48-60 h after the initiation of empirical piperacillin-tazobactam monotherapy. Of 763 eligible patients, 165 with persistent fever were randomized to receive piperacillin-tazobactam therapy plus either vancomycin therapy or placebo. Defervescence was observed in 82 (95%) of 86 patients in the vancomycin group and in 73 (92%) of 79 patients in the placebo group (P=.52). The distributions of the time to defervescence were not statistically significant between the 2 groups (estimated hazard ratio, 1.03; 95% confidence interval, 0.75-1.43; P=.75). The number of additional episodes of gram-positive bacteremia and the percentage of patients for whom amphotericin B was empirically added to their therapy regimen were also similar in both groups. This study failed to demonstrate that the empirical addition of vancomycin therapy to the treatment regimen is of benefit to persistently febrile neutropenic patients with cancer.
Assuntos
Febre/tratamento farmacológico , Neoplasias/tratamento farmacológico , Ácido Penicilânico/efeitos adversos , Piperacilina/efeitos adversos , Vancomicina/uso terapêutico , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Método Duplo-Cego , Febre/induzido quimicamente , Humanos , Pessoa de Meia-Idade , Neoplasias/complicações , Neoplasias/fisiopatologia , Neutropenia/etiologia , Ácido Penicilânico/análogos & derivados , Ácido Penicilânico/uso terapêutico , Piperacilina/uso terapêutico , Combinação Piperacilina e Tazobactam , Resultado do TratamentoRESUMO
In gram-negative bacteria, the outer membrane lipopolysaccharide is the main component triggering cytokine release from peripheral blood mononuclear cells (PBMCs). In gram-positive bacteria, purified walls also induce cytokine release, but stimulation requires 100 times more material. Gram-positive walls are complex megamolecules reassembling distinct structures. Only some of them might be inflammatory, whereas others are not. Teichoic acids (TA) are an important portion (> or =50%) of gram-positive walls. TA directly interact with C3b of complement and the cellular receptor for platelet-activating factor. However, their contribution to wall-induced cytokine-release by PBMCs has not been studied in much detail. In contrast, their membrane-bound lipoteichoic acids (LTA) counterparts were shown to trigger inflammation and synergize with peptidoglycan (PGN) for releasing nitric oxide (NO). This raised the question as to whether TA are also inflammatory. We determined the release of tumor necrosis factor (TNF) by PBMCs exposed to a variety of TA-rich and TA-free wall fragments from Streptococcus pneumoniae and Staphylococcus aureus. TA-rich walls from both organisms induced measurable TNF release at concentrations of 1 microg/ml. Removal of wall-attached TA did not alter this activity. Moreover, purified pneumococcal and staphylococcal TA did not trigger TNF release at concentrations as high as > or =100 microg/ml. In contrast, purified LTA triggered TNF release at 1 microg/ml. PGN-stem peptide oligomers lacking TA or amino-sugars were highly active and triggered TNF release at concentrations as low as 0.01 microg/ml (P. A. Majcherczyk, H. Langen, et al., J. Biol. Chem. 274:12537-12543,1999). Thus, although TA is an important part of gram-positive walls, it did not participate to the TNF-releasing activity of PGN.
Assuntos
Parede Celular/química , Monócitos/metabolismo , Staphylococcus aureus/imunologia , Streptococcus pneumoniae/imunologia , Ácidos Teicoicos/farmacologia , Fator de Necrose Tumoral alfa/biossíntese , Parede Celular/fisiologia , Humanos , Lipopolissacarídeos/farmacologiaRESUMO
OBJECTIVE: To assess the efficacy and safety of clinafloxacin as a single agent for the empirical treatment of febrile episodes and bacterial infections in neutropenic cancer patients. METHODS: An open label, active-controlled, randomized, parallel treatment, multicenter study was conducted where clinafloxacin monotherapy was compared to the combination of ceftazidime plus amikacin (plus optional vancomycin or teicoplanin). Four hundred and nineteen patients were randomized to receive either intravenous clinafloxacin 200 mg every 12 h or intravenous ceftazidime (2 g) iv every 8 h plus intravenous amikacin (15 mg/kg) per day in divided doses. All randomized patients were to receive a minimum of 48 h of primary study drug treatment, after which the primary treatment could be modified. Clinical and microbiological responses were evaluated at 7-21 days post-treatment after study treatment and long term (maximum 28 days), in intent-to-treat and modified intent-to-treat populations. RESULTS: Clinafloxacin and ceftazidime-amikacin were statistically equivalent for the 72-h defervescence rate, overall defervescence rate, time to defervescence, clinical success rate, by-pathogen microbiological eradication rate, and survival rate. Clinical cure was achieved in 84% (59/70) of patients who received clinafloxacin monotherapy. There were no significant differences between treatments in rates of adverse events or treatment discontinuation rates due to adverse events. CONCLUSIONS: Clinafloxacin appears to be an appropriate agent for empirical treatment in febrile neutropenic cancer patients.
Assuntos
Amicacina/uso terapêutico , Anti-Infecciosos/uso terapêutico , Infecções Bacterianas/tratamento farmacológico , Ceftazidima/uso terapêutico , Fluoroquinolonas , Neoplasias/complicações , Neutropenia/tratamento farmacológico , Adolescente , Adulto , Idoso , Amicacina/efeitos adversos , Antibacterianos/efeitos adversos , Antibacterianos/uso terapêutico , Anti-Infecciosos/efeitos adversos , Infecções Bacterianas/etiologia , Ceftazidima/efeitos adversos , Cefalosporinas/efeitos adversos , Cefalosporinas/uso terapêutico , Farmacorresistência Bacteriana , Quimioterapia Combinada/efeitos adversos , Feminino , Febre/tratamento farmacológico , Febre/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Neutropenia/etiologia , Teicoplanina/efeitos adversos , Teicoplanina/uso terapêutico , Resultado do Tratamento , Vancomicina/efeitos adversos , Vancomicina/uso terapêuticoRESUMO
The therapeutic efficacy of BAL9141 (formerly Ro 63-9141), a novel cephalosporin with broad in vitro activity that also has activity against methicillin-resistant Staphylococcus aureus (MRSA), was investigated in rats with experimental endocarditis. The test organisms were homogeneously methicillin-resistant S. aureus strain COL transformed with the penicillinase-encoding plasmid pI524 (COL Bla+) and homogeneously methicillin-resistant, penicillinase-producing isolate P8-Hom, selected by serial exposure of parent strain P8 to methicillin. The MICs of BAL9141 for these organisms (2 mg/liter) were low, and BAL9141was bactericidal in time-kill curve studies after 24 h of exposure to either two, four, or eight times the MIC. Rats with experimental endocarditis were treated in a three-arm study with a continuous infusion of BAL5788 (formerly Ro 65-5788), a carbamate prodrug of BAL9141, or with amoxicillin-clavulanate or vancomycin. The rats were administered BAL9141 to obtain steady-state target levels of 20, 10, and 5 mg of per liter or were administered either 1.2 g of amoxicillin-clavulanate (ratio 5:1) every 6 h or 1 g of vancomycin every 12 h at changing flow rates to simulate the pharmacokinetics produced in humans by intermittent intravenous treatment. Treatment was started 12 h after bacterial challenge and lasted for 3 days. BAL9141 was successful in the treatment of experimental endocarditis due to either MRSA isolate COL Bla+ or MRSA isolate P8-Hom at the three targeted steady-state concentrations and sterilized >90% of cardiac vegetations (P < 0.005 versus controls; P < 0.05 versus amoxicillin-clavulanate and vancomycin treatment groups). These promising in vivo results with BAL9141 correlated with the high affinity of the drug for PBP 2a and its stability to penicillinase hydrolysis observed in vitro.
Assuntos
Proteínas de Bactérias , Cefalosporinas/uso terapêutico , Endocardite Bacteriana/tratamento farmacológico , Hexosiltransferases , Peptidil Transferases , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos , Animais , Proteínas de Transporte/metabolismo , Cefalosporinas/sangue , Cefalosporinas/farmacologia , Estabilidade de Medicamentos , Endocardite Bacteriana/sangue , Resistência a Meticilina , Testes de Sensibilidade Microbiana , Muramilpentapeptídeo Carboxipeptidase/metabolismo , Proteínas de Ligação às Penicilinas , Penicilinase/metabolismo , Ratos , Infecções Estafilocócicas/sangue , Fatores de Tempo , Resultado do TratamentoRESUMO
Discovered in the early 1960s as a T-cell cytokine, MIF has emerged to be an important mediator of the innate immune system. MIF was identified recently to be released by a vast array of cells, including monocytes/macrophages, T-cells, B-cells, endocrine cells and epithelial cells in response to infection and stress. Bacteria, microbial toxins and cytokines have been shown to be powerful inducers of MIF secretion by macrophages. MIF stimulates the expression of pro-inflammatory mediators by immune cells and functions to counterbalance the anti-inflammatory and immunosuppressive effects of glucocorticoids. Like TNF and IL-1, MIF plays an important role in host responses to infection. Recombinant MIF was found to exacerbate lethal endotoxemia or bacterial sepsis when co-injected with LPS or Escherichia coli in mice. Conversely, MIF knockout mice or mice treated with anti-MIF antibodies were protected from shock induced by LPS, staphylococcal exotoxins or bacterial peritonitis, even when anti-MIF therapy was started after the onset of infection. Given the central role played by MIF in innate immune responses against microbial pathogens and in the regulation of inflammatory responses, pharmacological modulation of MIF production or neutralization of MIF activity could have broad clinical applications and may offer new treatment options for the management of patients with severe sepsis or septic shock.
Assuntos
Endotoxinas/farmacologia , Infecções por Bactérias Gram-Negativas/imunologia , Fatores Inibidores da Migração de Macrófagos/fisiologia , Animais , Citocinas/análise , Citocinas/imunologia , Modelos Animais de Doenças , Endotoxemia/imunologia , Endotoxemia/prevenção & controle , Infecções por Escherichia coli/imunologia , Glucocorticoides/fisiologia , Infecções por Bactérias Gram-Negativas/metabolismo , Imunidade Inata , Lipopolissacarídeos/farmacologia , Camundongos , Camundongos Knockout , Peritonite/imunologia , Peritonite/prevenção & controle , Choque Séptico/imunologia , Choque Séptico/prevenção & controleRESUMO
The new 8-methoxyquinolone moxifloxacin was tested against two ciprofloxacin-susceptible Staphylococcus aureus strains (strains P8 and COL) and two ciprofloxacin-resistant derivatives of strain P8 carrying a single grlA mutation (strain P8-4) and double grlA and gyrA mutations (strain P8-128). All strains were resistant to methicillin. The MICs of ciprofloxacin and moxifloxacin were 0.5 and 0.125 mg/liter, respectively, for P8; 0.25 and 0.125 mg/liter, respectively, for COL; 8 and 0.25 mg/liter, respectively, for P8-4; and >or=128 and 2 mg/liter, respectively, for P8-128. In vitro, the rate of spontaneous resistance of P8 and COL was 10(-7) on agar plates containing ciprofloxacin at two times the MIC, whereas it was Assuntos
Antibacterianos/uso terapêutico
, Anti-Infecciosos/uso terapêutico
, Compostos Aza
, Ciprofloxacina/uso terapêutico
, Endocardite Bacteriana/tratamento farmacológico
, Fluoroquinolonas
, Quinolinas
, Infecções Estafilocócicas/tratamento farmacológico
, Staphylococcus aureus/efeitos dos fármacos
, Staphylococcus aureus/genética
, Vancomicina/uso terapêutico
, Animais
, Antibacterianos/farmacocinética
, Anti-Infecciosos/farmacocinética
, Ciprofloxacina/farmacocinética
, DNA Girase/genética
, Resistência Microbiana a Medicamentos
, Endocardite Bacteriana/sangue
, Endocardite Bacteriana/microbiologia
, Resistência a Meticilina
, Testes de Sensibilidade Microbiana
, Moxifloxacina
, Ratos
, Baço/microbiologia
, Infecções Estafilocócicas/sangue
, Infecções Estafilocócicas/microbiologia
, Vancomicina/farmacocinética
RESUMO
LPS-binding protein (LBP) and CD14 potentiate cell activation by LPS, contributing to lethal endotoxemia. We analyzed the contribution of LBP/CD14 in models of bacterial infection. Mice pretreated with mAbs neutralizing CD14 or LBP showed a delay in TNF-alpha production and died of overwhelming infection within 24 h, after a challenge with 250 CFU of virulent Klebsiella pneumoniae. Blockade of TNF-alpha also increased lethality, whereas pretreatment with TNF-alpha protected mice, even in the presence of LBP and CD14 blockade. Anti-LBP or anti-CD14 mAbs did not improve or decrease lethality with a higher inoculum (10(5) K. pneumoniae) and did not affect outcome following injections of low or high inocula of Escherichia coli O111. These results point to the essential role of LBP/CD14 in innate immunity against virulent bacteria.
Assuntos
Proteínas de Fase Aguda , Proteínas de Transporte/imunologia , Proteínas de Transporte/metabolismo , Bactérias Gram-Negativas/imunologia , Receptores de Lipopolissacarídeos/metabolismo , Lipopolissacarídeos/metabolismo , Glicoproteínas de Membrana , Animais , Anticorpos Monoclonais , Bacteriemia/etiologia , Bacteriemia/imunologia , Proteínas de Transporte/antagonistas & inibidores , Endotoxemia/imunologia , Escherichia coli/imunologia , Escherichia coli/patogenicidade , Feminino , Bactérias Gram-Negativas/patogenicidade , Infecções por Bactérias Gram-Negativas/etiologia , Infecções por Bactérias Gram-Negativas/imunologia , Klebsiella pneumoniae/imunologia , Klebsiella pneumoniae/patogenicidade , Lipopolissacarídeos/toxicidade , Camundongos , Testes de Neutralização , Neutrófilos/imunologia , Sepse/etiologia , Sepse/imunologia , Fator de Necrose Tumoral alfa/biossíntese , Fator de Necrose Tumoral alfa/farmacologia , VirulênciaRESUMO
OBJECTIVES: To review the role of macrophage migration inhibitory factor (MIF) in host responses to infection and to explore the potential of MIF as a novel target for therapeutic intervention in patients with severe sepsis and septic shock. DATA SOURCES: Published articles on the role of MIF in innate immune responses against microbial pathogens. DATA SUMMARY: MIF has emerged recently as an important effector molecule of the innate immune system. MIF is expressed constitutively by monocytes/macrophages, T cells, B cells, endocrine cells, and epithelial cells. Microbial toxins and cytokines are powerful inducers of MIF release by immune cells. MIF expression is up-regulated during the course of inflammatory and infectious diseases and was found to play an important role in the pathogenesis of sepsis and septic shock. CONCLUSION: Given the role of MIF in innate immune responses against microbial pathogens and in the regulation of inflammatory responses, modulation of MIF production or neutralization of its activity may offer new therapeutic options for the management of patients with sepsis.
Assuntos
Infecções Bacterianas/imunologia , Imunidade Celular/imunologia , Imunidade Inata/imunologia , Fatores Inibidores da Migração de Macrófagos/imunologia , Sepse/imunologia , Choque Séptico/imunologia , Animais , Infecções Bacterianas/microbiologia , Infecções Bacterianas/mortalidade , Infecções Bacterianas/terapia , Citocinas/imunologia , Modelos Animais de Doenças , Endotoxinas/imunologia , Humanos , Inflamação , Macrófagos/imunologia , Monócitos/imunologia , Sepse/microbiologia , Sepse/mortalidade , Sepse/terapia , Choque Séptico/microbiologia , Choque Séptico/mortalidade , Choque Séptico/terapia , Transdução de Sinais/imunologia , Regulação para Cima/imunologiaRESUMO
The antifungal agent fluconazole (FLC) is widely used in clinical practice. Monitoring FLC levels is useful in complicated clinical settings and in experimental infection models. A bioassay using Candida pseudotropicalis, a simple and cost-effective method, is validated only for FLC levels ranging from 5 to 40 mg/liter. An extension of the analytical range is needed to cover most yeast MICs. A new bioassay in RPMI agar containing methylene blue was developed using C. albicans DSY1024, a mutant rendered hypersusceptible to FLC constructed by the deletion of the multidrug efflux transporter genes CDR1, CDR2, CaMDR1, and FLU1. Reproducible standard curves were obtained with FLC concentrations in plasma ranging from 1 to 100 mg/liter (quadratic regression coefficient > 0.997). The absolute sensitivity was 0.026 microg of FLC. The method was internally validated according to current guidelines for analytical method validation. Both accuracy and precision lied in the required +/-15% range. FLC levels measured by bioassay and by high-performance liquid chromatography (HPLC) performed with 62 plasma samples from humans and rats showed a strong correlation (coefficients, 0.979 and 0.995, respectively; percent deviations of bioassay from HPLC values, 0.44% +/- 15.31% and 2.66% +/- 7.54%, respectively). In summary, this newly developed bioassay is sensitive, simple, rapid, and inexpensive. It allows nonspecialized laboratories to determine FLC levels in plasma to within the clinically relevant concentration range and represents a useful tool for experimental treatment models.
Assuntos
Antifúngicos/sangue , Candida albicans/efeitos dos fármacos , Fluconazol/sangue , Animais , Antifúngicos/farmacologia , Azóis/sangue , Azóis/farmacologia , Bioensaio , Candida albicans/genética , Cromatografia Líquida de Alta Pressão , Contagem de Colônia Microbiana , Feminino , Fluconazol/farmacologia , Humanos , Testes de Sensibilidade Microbiana , Modelos Animais , Ratos , Ratos WistarRESUMO
Because Staphylococcus aureus strains contain multiple virulence factors, studying their pathogenic role by single-gene inactivation generated equivocal results. To circumvent this problem, we have expressed specific S. aureus genes in the less virulent organism Streptococcus gordonii and tested the recombinants for a gain of function both in vitro and in vivo. Clumping factor A (ClfA) and coagulase were investigated. Both gene products were expressed functionally and with similar kinetics during growth by streptococci and staphylococci. ClfA-positive S. gordonii was more adherent to platelet-fibrin clots mimicking cardiac vegetations in vitro and more infective in rats with experimental endocarditis (P < 0.05). Moreover, deleting clfA from clfA-positive streptococcal transformants restored both the low in vitro adherence and the low in vivo infectivity of the parent. Coagulase-positive transformants, on the other hand, were neither more adherent nor more infective than the parent. Furthermore, coagulase did not increase the pathogenicity of clfA-positive streptococci when both clfA and coa genes were simultaneously expressed in an artificial minioperon in streptococci. These results definitively attribute a role for ClfA, but not coagulase, in S. aureus endovascular infections. This gain-of-function strategy might help solve the role of individual factors in the complex the S. aureus-host relationship.
Assuntos
Coagulase/genética , Staphylococcus aureus/patogenicidade , Streptococcus/patogenicidade , Transformação Bacteriana , Animais , Aderência Bacteriana , Endocardite Bacteriana/etiologia , Ratos , Staphylococcus aureus/genética , Streptococcus/genética , VirulênciaRESUMO
OBJECTIVES: In patients with septic shock, circulating monocytes become refractory to stimulation with microbial products. Whether this hyporesponsive state is induced by infection or is related to shock is unknown. To address this question, we measured TNF alpha production by monocytes or by whole blood obtained from healthy volunteers (controls), from patients with septic shock, from patients with severe infection (bacterial pneumonia) without shock, and from patients with cardiogenic shock without infection. MEASUREMENTS: The numbers of circulating monocytes, of CD14+ monocytes, and the expression of monocyte CD14 and the LPS receptor, were assessed by flow cytometry. Monocytes or whole blood were stimulated with lipopolysaccharide endotoxin (LPS), heat-killed Escherichia coli or Staphylococcus aureus, and TNF alpha production was measured by bioassay. RESULTS: The number of circulating monocytes, of CD14+ monocytes, and the monocyte CD14 expression were significantly lower in patients with septic shock than in controls, in patients with bacterial pneumonia or in those with cardiogenic shock (p < 0.001). Monocytes or whole blood of patients with septic shock exhibited a profound deficiency of TNF alpha production in response to all stimuli (p < 0.05 compared to controls). Whole blood of patients with cardiogenic shock also exhibited this defect (p < 0.05 compared to controls), although to a lesser extent, despite normal monocyte counts and normal CD14 expression. CONCLUSIONS: Unlike patients with bacterial pneumonia, patients with septic or cardiogenic shock display profoundly defective TNF alpha production in response to a broad range of infectious stimuli. Thus, down-regulation of cytokine production appears to occur in patients with systemic, but not localised, albeit severe, infections and also in patients with non-infectious circulatory failure. Whilst depletion of monocytes and reduced monocyte CD14 expression are likely to be critical components of the hyporesponsiveness observed in patients with septic shock, other as yet unidentified factors are at work in this group and in patients with cardiogenic shock.
Assuntos
Receptores de Lipopolissacarídeos/sangue , Linfócitos/imunologia , Monócitos/imunologia , Pneumonia Bacteriana/imunologia , Choque Cardiogênico/imunologia , Choque Séptico/imunologia , Fator de Necrose Tumoral alfa/biossíntese , Antígenos CD/sangue , Células Cultivadas , Infecções Comunitárias Adquiridas/sangue , Infecções Comunitárias Adquiridas/imunologia , Humanos , Lipopolissacarídeos/farmacologia , Linfócitos/efeitos dos fármacos , Monócitos/efeitos dos fármacos , Pneumonia Bacteriana/sangue , Valores de Referência , Choque Cardiogênico/sangue , Choque Séptico/sangueRESUMO
Plasma lipopolysaccharide (LPS)-binding protein (LBP) and membrane CD14 function to enhance the responses of monocytes to low concentrations of endotoxin. Surprisingly, recent reports have suggested that LBP or CD14 may be dispensable for macrophage responses to low concentrations of LPS or may even exert an inhibitory effect in the case of LBP. We therefore investigated whether LBP and CD14 participated in the response of mouse peritoneal exudate macrophages (PEM) to LPS stimulation. In the presence of a low amount of plasma (<1%) or of recombinant mouse or human LBP, PEM were found to respond to low concentrations of LPS (<5 to 10 ng/ml) in an LBP- and CD14-dependent manner. However, tumor necrosis factor production (not interleukin-6 production) by LPS-stimulated PEM was reduced when cells were stimulated in the presence of higher concentrations of plasma or serum (5 or 10%). Yet, the inhibitory effect of plasma or serum was not mediated by LBP. Taken together with previous results obtained with LBP and CD14 knockout mice in models of experimental endotoxemia, the present data confirm a critical part for LBP and CD14 in innate immune responses of both blood monocytes and tissue macrophages to endotoxins.
Assuntos
Proteínas de Fase Aguda , Proteínas de Transporte/fisiologia , Receptores de Lipopolissacarídeos/fisiologia , Lipopolissacarídeos/toxicidade , Macrófagos Peritoneais/efeitos dos fármacos , Glicoproteínas de Membrana , Plasma/fisiologia , Animais , Feminino , Humanos , Ativação de Macrófagos , Macrófagos Peritoneais/fisiologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Fator de Necrose Tumoral alfa/biossínteseRESUMO
Macrophages are pivotal effector cells of the innate immune system, which is vital for recognizing and eliminating invasive microbial pathogens. When microbial products bind to pathogen-recognition receptors, macrophages become activated and release a broad array of cytokines that orchestrate the host innate and adaptive immune responses. Initially identified as a T-cell cytokine, macrophage migration inhibitory factor (MIF) is also a macrophage cytokine and an important mediator of inflammation and sepsis. Here we report that MIF is an essential regulator of macrophage responses to endotoxin (lipopolysaccharide) and Gram-negative bacteria. Compared with wild-type cells, MIF-deficient macrophages are hyporesponsive to lipopolysaccharide and Gram-negative bacteria, as shown by a profound reduction in the activity of NF-kappaB and the production of tumour-necrosis factor-alpha. This reduction is due to a downregulation of Toll-like receptor 4 (TLR4), the signal-transducing molecule of the lipopolysaccharide receptor complex, and is associated with decreased activity of transcription factor PU.1, which is required for optimal expression of the Tlr4 gene in myeloid cells. These findings identify an important role for MIF in innate immunity and provide a molecular basis for the resistance of MIF-deficient mice to endotoxic shock.
Assuntos
Proteínas de Drosophila , Fatores Inibidores da Migração de Macrófagos/fisiologia , Macrófagos/imunologia , Animais , Células Cultivadas , Escherichia coli/imunologia , Regulação da Expressão Gênica , Bactérias Gram-Negativas/imunologia , Klebsiella pneumoniae/imunologia , Receptores de Lipopolissacarídeos/metabolismo , Lipopolissacarídeos/imunologia , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Knockout , NF-kappa B/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Pseudomonas aeruginosa/imunologia , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Choque Séptico/imunologia , Transdução de Sinais , Receptor 4 Toll-Like , Receptores Toll-Like , Transativadores/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Recent observations demonstrated that fluconazole plus cyclosporine (Cy) synergistically killed Candida albicans in vitro. This combination was tested in rats with C. albicans experimental endocarditis. The MICs of fluconazole and Cy for the test organism were 0.25 and >10 mg/liter, respectively. Rats were treated for 5 days with either Cy, amphotericin B, fluconazole, or fluconazole-Cy. Although used at high doses, the peak concentrations of fluconazole in the serum of rats (up to 4.5 mg/liter) were compatible with high-dose fluconazole therapy in humans. On the other hand, Cy concentrations in serum (up to 4.5 mg/liter) were greater than recommended therapeutic levels. Untreated rats demonstrated massive pseudohyphal growth in both the vegetations and the kidneys. However, only the kidneys displayed concomitant polymorphonuclear infiltration. The therapeutic results reflected this dissociation. In the vegetations, only the fungicidal fluconazole-Cy combination significantly decreased fungal densities compared to all groups, including amphotericin B (P < 0.0001). In the kidneys, all regimens except the Cy regimen were effective, but fluconazole-Cy remained superior to amphotericin B and fluconazole alone in sterilizing the organs (P < 0.0001). While the mechanism responsible for the fluconazole-Cy interaction is hypothetical, this observation opens new perspectives for fungicidal combinations between azoles and other drugs.
Assuntos
Antifúngicos/uso terapêutico , Candidíase/tratamento farmacológico , Ciclosporina/uso terapêutico , Endocardite/tratamento farmacológico , Fluconazol/uso terapêutico , Animais , Antifúngicos/farmacocinética , Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Candidíase/metabolismo , Ciclosporina/farmacocinética , Ciclosporina/farmacologia , Modelos Animais de Doenças , Resistência Microbiana a Medicamentos , Quimioterapia Combinada , Endocardite/metabolismo , Endocardite/microbiologia , Feminino , Fluconazol/farmacocinética , Fluconazol/farmacologia , Rim/efeitos dos fármacos , Rim/microbiologia , Testes de Sensibilidade Microbiana , Ratos , Ratos Wistar , Resultado do TratamentoRESUMO
OBJECTIVE: To analyze the implications for therapeutic advances in the treatment of sepsis and septic shock based on the mechanisms underlying the response to microbial infection. DATA SOURCES: Clinical trials and experimental models designed to determine the key mechanisms involved in cellular and molecular processes of inflammatory reactions. STUDY SELECTION: Analyses of normal immune reactions to microbial infection, processes involved in the development of sepsis, and reasons for frequent failure of regimens based on current therapeutic rationales. DATA EXTRACTION/SYNTHESIS: Review of the data suggests that the dysregulation of the immune system resulting in sepsis/septic shock is ineffectually blocked by interfering with the action of inflammatory mediators or cascades, as these processes may be too complex to be easily antagonized. Rather, blockade of the action of microbial products or of the intracellular processes activated by receptor interaction with these products may provide a more promising therapeutic alternative. CONCLUSIONS: The sepsis syndrome induced by microbial pathogens reflects excessive stimulation of the processes of innate immunity. Bacterial components reacting with specific receptors activate intracellular processes, resulting in the release of excessive amounts of mediators of inflammation as well as triggering multiple complex proteolytic cascades. Blockade or antagonism of the actions of individual intermediary messenger molecules has proved therapeutically unsuccessful, because blockade of mediators alone does not block the direct activation of processes such as coagulation and complement. The dysregulation that characterizes sepsis may be amenable to blockade of the bacterial components or to the intracellular pathways triggered by these products.
Assuntos
Sepse/fisiopatologia , Humanos , Sepse/tratamento farmacológico , Sepse/imunologiaRESUMO
Penicillin tolerance is an incompletely understood phenomenon that allows bacteria to resist drug-induced killing. Tolerance was studied with independent Streptococcus gordonii mutants generated by cyclic exposure to 500 times the MIC of penicillin. Parent cultures lost 4 to 5 log(10) CFU/ml of viable counts/24 h. In contrast, each of four independent mutant cultures lost < or =2 log(10) CFU/ml/24 h. The mutants had unchanged penicillin-binding proteins but contained increased amounts of two proteins with respective masses of ca. 50 and 45 kDa. One mutant (Tol1) was further characterized. The two proteins showing increased levels were homologous to the arginine deiminase and ornithine carbamoyl transferase of other gram-positive bacteria and were encoded by an operon that was >80% similar to the arginine-deiminase (arc) operon of these organisms. Partial nucleotide sequencing and insertion inactivation of the S. gordonii arc locus indicated that tolerance was not a direct consequence of arc alteration. On the other hand, genetic transformation of tolerance by Tol1 DNA always conferred arc deregulation. In nontolerant recipients, arc was repressed during exponential growth and up-regulated during postexponential growth. In tolerant transformants, arc was constitutively expressed. Tol1 DNA transformed tolerance at the same rate as transformation of a point mutation (10(-2) to 10(-3)). The tolerance mutation mapped on a specific chromosomal fragment but was physically distant from arc. Importantly, arc deregulation was observed in most (6 of 10) of additional independent penicillin-tolerant mutants. Thus, although not exclusive, the association between arc deregulation and tolerance was not fortuitous. Since penicillin selection mimicked the antibiotic pressure operating in the clinical environment, arc deregulation might be an important correlate of naturally occurring tolerance and help in understanding the mechanism(s) underlying this clinically problematic phenotype.