RESUMO
Resistant Gram-negative bacteria are a growing concern in the United States, leading to significant morbidity and mortality. We identified a 72-year-old female patient who presented with unilateral vision loss. She was found to have a large corneal ulcer with hypopyon. Culture of corneal scrapings grew extensively drug-resistant Pseudomonas aeruginosa. Treatment involved a combination of systemic and topical antibiotics. Whole genome sequencing revealed the presence of blaVIM-80, blaGES-9, and other resistance determinants. This distinctive organism was linked to an over-the-counter artificial tears product.
Assuntos
Úlcera da Córnea , Infecções por Pseudomonas , Feminino , Humanos , Idoso , Úlcera da Córnea/tratamento farmacológico , Úlcera da Córnea/microbiologia , Pseudomonas aeruginosa/genética , Antibacterianos/uso terapêutico , Bactérias Gram-Negativas , Infecções por Pseudomonas/microbiologia , Testes de Sensibilidade MicrobianaRESUMO
We have previously demonstrated that mycobacterial lipoproteins engage TLR2 on human CD4(+) T cells and upregulate TCR-triggered IFN-γ secretion and cell proliferation in vitro. Here we examined the role of CD4(+) T-cell-expressed TLR2 in Mycobacterium tuberculosis (MTB) Ag-specific T-cell priming and in protection against MTB infection in vivo. Like their human counterparts, mouse CD4(+) T cells express TLR2 and respond to TLR2 costimulation in vitro. This Th1-like response was observed in the context of both polyclonal and Ag-specific TCR stimulation. To evaluate the role of T-cell TLR2 in priming of CD4(+) T cells in vivo, naive MTB Ag85B-specific TCR transgenic CD4(+) T cells (P25 TCR-Tg) were adoptively transferred into Tlr2(-/-) recipient C57BL/6 mice that were then immunized with Ag85B and with or without TLR2 ligand Pam3 Cys-SKKKK. TLR2 engagement during priming resulted in increased numbers of IFN-γ-secreting P25 TCR-Tg T cells 1 week after immunization. P25 TCR-Tg T cells stimulated in vitro via TCR and TLR2 conferred more protection than T cells stimulated via TCR alone when adoptively transferred before MTB infection. Our findings indicate that TLR2 engagement on CD4(+) T cells increases MTB Ag-specific responses and may contribute to protection against MTB infection.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Mycobacterium tuberculosis/imunologia , Receptor 2 Toll-Like/imunologia , Tuberculose/imunologia , Aciltransferases/biossíntese , Aciltransferases/genética , Aciltransferases/imunologia , Aciltransferases/farmacologia , Animais , Antígenos de Bactérias/biossíntese , Antígenos de Bactérias/genética , Antígenos de Bactérias/imunologia , Antígenos de Bactérias/metabolismo , Antígenos de Bactérias/farmacologia , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/farmacologia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD4-Positivos/patologia , Homólogo 5 da Proteína Cromobox , Humanos , Imunização , Interferon gama/biossíntese , Interferon gama/genética , Interferon gama/imunologia , Camundongos , Camundongos Knockout , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/metabolismo , Receptor 2 Toll-Like/biossíntese , Receptor 2 Toll-Like/genética , Tuberculose/genética , Tuberculose/metabolismo , Tuberculose/patologia , Tuberculose/prevenção & controleRESUMO
Despite its use for decades, pharmacokinetic (PK) and safety studies on colistin are limited. We conducted a phase l, open-label trial to evaluate the safety and PK of multiple doses of intravenous (IV) and aerosolized colistimethate sodium (CMS) administered separately and in combination. In total, 31 healthy adults were enrolled into three cohorts of 9, 10, and 12 participants, respectively. Each cohort received increasing doses of CMS over three dosing periods as follows: Period 1 (IV only), 2.5 mg/kg every 12 h (q12h) to 3.3 mg/kg every 8 h (q8h); Period 2 (aerosolized only), 75 mg 2-4 doses, and Period 3 (combined IV aerosolized), in which was Periods 1 and 2 combined. Safety assessments, serum and lung concentrations of colistin analytes (colistin A, colistin B, CMS A, and CMS B), and kidney biomarkers were measured at specified time points. Increasing the CMS dose from 2.5 mg/kg q12h to q8h resulted in a 33% increase in serum colistin A concentrations from 3.9 µg/mL to 5.3 µg/mL-well above the accepted target of 2 µg/mL for 6 h after dosing, without evidence of nephrotoxicity. However, there was an increase in neurotoxicity, primarily perioral and lingual paresthesias, and self-limited ataxia. IV administration did not increase the lung concentrations of colistin.
Assuntos
Abscesso Encefálico/etiologia , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Hospedeiro Imunocomprometido , Doenças Pulmonares Intersticiais/etiologia , Toxoplasma/isolamento & purificação , Toxoplasmose/diagnóstico , Toxoplasmose/patologia , Abscesso Encefálico/parasitologia , Abscesso Encefálico/patologia , Febre , Humanos , Doenças Pulmonares Intersticiais/parasitologia , Doenças Pulmonares Intersticiais/patologia , Masculino , Toxoplasmose/parasitologia , Adulto JovemRESUMO
OBJECTIVES: Successful decolonisation of nasal Staphylococcus aureus (SA) carriage by mupirocin is limited by increasing drug resistance. This randomised, open-label, phase 1 study compared the safety and local tolerability of two nasal formulations of XF-73, a novel porphyrinic antibacterial with rapid intrinsic activity against SA. METHODS: The study was performed in 60 healthy adults. In Part 1, eight non-SA carriers were randomised to groups of four subjects each and were treated with XF-73 concentrations of 0.5mg/g 2% gel or 2.0mg/g 2% gel. In Part 2, 52 persistent SA carriers were randomised to groups of 13 subjects each and were treated with XF-73 concentrations of 0.5mg/g 2% gel, 2.0mg/g 2% gel, 0.5mg/g 4% gel or 4% viscosified placebo gel. Plasma pharmacokinetic and pharmacodynamic studies were performed. Antistaphylococcal activity was assessed as the presence/absence of SA and by quantification of colonisation using a semiquantitative scale (SA score). RESULTS: 56 subjects (8/8 from Part 1 and 48/52 from Part 2) completed the study, with 47/60 comprising the pharmacokinetic population and 48/60 the pharmacodynamic population. There was no measurable systemic absorption of XF-73. XF-73 treatment was associated with rapid reduction in SA score in all subjects. The most common treatment-emergent adverse events (TEAEs) were rhinorrhoea and nasal dryness (15.5% each in Parts 1 and 2). TEAEs were mild and resolved spontaneously. CONCLUSION: XF-73 was well tolerated with minimal side effects at doses of 0.5mg/g 2% gel and 2.0mg/g 2% gel. These findings support further development of XF-73.
Assuntos
Infecções Estafilocócicas , Staphylococcus aureus , Adulto , Antibacterianos/efeitos adversos , Humanos , Mupirocina , Nariz , Infecções Estafilocócicas/tratamento farmacológicoRESUMO
Immune evasion is required for Mycobacterium tuberculosis to survive in the face of robust adaptive CD4(+) T-cell responses. We have previously shown that M. tuberculosis can indirectly inhibit CD4(+) T cells by suppressing the major histocompatibility complex class II antigen-presenting cell function of macrophages. This study was undertaken to determine if M. tuberculosis could directly inhibit CD4(+) T-cell activation. Murine CD4(+) T cells were purified from spleens by negative immunoaffinity selection followed by flow sorting. Purified CD4(+) T cells were activated for 16 to 48 h with CD3 and CD28 monoclonal antibodies in the presence or absence of M. tuberculosis and its subcellular fractions. CD4(+) T-cell activation was measured by interleukin 2 production, proliferation, and expression of activation markers, all of which were decreased in the presence of M. tuberculosis. Fractionation identified that M. tuberculosis cell wall glycolipids, specifically, phosphatidylinositol mannoside and mannose-capped lipoarabinomannan, were potent inhibitors. Glycolipid-mediated inhibition was not dependent on Toll-like receptor signaling and could be bypassed through stimulation with phorbol 12-myristate 13-acetate and ionomycin. ZAP-70 phosphorylation was decreased in the presence of M. tuberculosis glycolipids, indicating that M. tuberculosis glycolipids directly inhibited CD4(+) T-cell activation by interfering with proximal T-cell-receptor signaling.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Parede Celular/imunologia , Glicolipídeos/imunologia , Ativação Linfocitária , Mycobacterium tuberculosis/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Animais , Proliferação de Células , Células Cultivadas , Feminino , Citometria de Fluxo , Humanos , Interleucina-2/metabolismo , Camundongos , Transdução de Sinais , Baço/imunologiaRESUMO
Mycobacterium tuberculosis and M. bovis BCG infect APCs. In vitro, mycobacteria inhibit IFN-gamma-induced MHC-II expression by macrophages, but the effects of mycobacteria on lung APCs in vivo remain unclear. To assess MHC-II expression on APCs infected in vivo, mice were aerosol-infected with GFP-expressing BCG. At 28 d, approximately 1% of lung APCs were GFP+ by flow cytometry and CFU data. Most GFP+ cells were CD11b(high)/CD11c(neg-mid) lung macrophages (58-68%) or CD11b(high)/CD11c(high) DCs (28-31%). Lung APC MHC-II expression was higher in infected mice than naïve mice. Within infected lungs, however, MHC-II expression was lower in GFP+ cells than GFP- cells for both macrophages and DCs. MHC-II expression was also inhibited on purified lung macrophages and DCs that were infected with BCG in vitro. Thus, lung APCs that harbor mycobacteria in vivo have decreased MHC-II expression relative to uninfected APCs from the same lung, possibly contributing to evasion of T cell responses.
Assuntos
Células Dendríticas/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Macrófagos Alveolares/imunologia , Mycobacterium bovis/imunologia , Tuberculose/imunologia , Animais , Células Apresentadoras de Antígenos/imunologia , Células da Medula Óssea/citologia , Células da Medula Óssea/imunologia , Antígenos CD11/imunologia , Diferenciação Celular/imunologia , Feminino , Macrófagos Alveolares/citologia , Camundongos , Camundongos Endogâmicos C57BLRESUMO
We have previously reported that during mycobacterial infection, naïve CD4(+) T-cell activation is enhanced in the lungs. We investigated the role of chemokine receptor CCR7 and its ligands in the ability of CD11c(+) lung dendritic cells (DCs) to activate naïve CD4(+) T cells during pulmonary infection with Mycobacterium bovis bacillus Calmette-Guérin (BCG). BCG infection resulted in the accumulation and maturation in the lungs of DCs that persisted as the mycobacterial burden declined. Lung DCs from infected mice expressed more major histocompatibility complex class II (MHC-II) than those from uninfected mice. CCR7 expression levels on lung DCs were comparable among uninfected and infected mice. The gene expression of the CCR7 ligand CCL19 progressively increased throughout BCG infection, and its expression was MyD88 dependent. CD11c(+) lung cells from BCG-infected mice activated ovalbumin (OVA)-specific naïve CD4(+) T cells more than CD11c(+) lung cells from uninfected mice. Interestingly, during peak mycobacterial infection, CD11c(hi) MHC(hi) lung DCs had slightly decreased chemotaxis toward the CCR7 ligand CCL21 and less efficiency in activating naive CD4(+) T cells than DCs from mice during late-stage infection, when few bacilli are found in the lung. These findings suggest that during BCG infection, the inflammation and sustained expression of CCL19 result in the recruitment, activation, and retention in the lung of DCs that can activate naïve CD4(+) T cells in situ.
Assuntos
Células Dendríticas/imunologia , Pulmão/imunologia , Infecções por Mycobacterium/imunologia , Mycobacterium bovis/imunologia , Animais , Antígeno CD11c/análise , Linfócitos T CD4-Positivos/imunologia , Quimiocina CCL19/biossíntese , Células Dendríticas/química , Antígenos de Histocompatibilidade Classe II/biossíntese , Pulmão/citologia , Camundongos , Infecções por Mycobacterium/microbiologia , Fator 88 de Diferenciação Mieloide/genética , Fator 88 de Diferenciação Mieloide/fisiologia , Receptores CCR7/biossínteseRESUMO
A hallmark of M. tuberculosis infection is the ability of most (90-95%) healthy adults to control infection through acquired immunity, in which antigen specific T cells and macrophages arrest growth of M. tuberculosis bacilli and maintain control over persistent bacilli. In addition to CD4+ T cells, other T cell subsets such as, gammadelta, CD8+ and CD1-restricted T cells have roles in the immune response to M. tuberculosis. A diverse T cell response allows the host to recognize a wider range of mycobacterial antigens presented by different families of antigen-presenting molecules, and thus greater ability to detect the pathogen. Macrophages are key antigen presenting cells for T cells, and M. tuberculosis survives and persists in this central immune cell. This is likely an important factor in generating this T cell diversity. Furthermore, the slow growth and chronic nature of M. tuberculosis infection results in prolonged exposure to antigens, and hence further T cell sensitization. The effector mechanisms used by T cells to control M. tuberculosis are poorly understood. To survive in macrophages, M. tuberculosis has evolved mechanisms to block immune responses. These include modulation of phagosomes, neutralization of macrophage effector molecules, stimulating the secretion of inhibitory cytokines, and interfering with processing of antigens for T cells. The relative importance of these blocking mechanisms likely depends on the stage of M. tuberculosis infection: primary infection, persistence, reactivation or active tuberculosis. The balance of the host-pathogen interaction in M. tuberculosis infection is determined by the interaction of T cells and infected macrophages. The outcome of this interaction results either in control of M. tuberculosis infection or active disease. A better understanding of this interaction will result in improved approaches to treatment and prevention of tuberculosis.
Assuntos
Apresentação de Antígeno , Mycobacterium tuberculosis/imunologia , Subpopulações de Linfócitos T/imunologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Humanos , Imunidade Celular , Receptores de Antígenos de Linfócitos T gama-delta/análiseRESUMO
During pulmonary mycobacterial infection, there is increased trafficking of dendritic cells from the lungs to the draining lymph nodes. We hypothesized that ongoing mycobacterial infection would modulate recruitment and activation of antigen-specific naive CD4+ T cells after airway antigen challenge. BALB/c mice were infected by aerosol with Mycobacterium bovis BCG. At peak bacterial burden in the lungs (4 to 6 weeks postinfection), carboxy-fluorescein diacetate succinimidyl ester-labeled naive ovalbumin-specific DO11.10 T cells were adoptively transferred into infected and uninfected mice. Recipient mice were challenged intranasally with soluble ovalbumin (OVA), and OVA-specific T-cell responses were measured in the lungs, draining mediastinal lymph nodes (MLN), and spleens. OVA challenge resulted in increased activation and proliferation of OVA-specific T cells in the draining MLN of both infected and uninfected mice. However, only BCG-infected mice had prominent OVA-specific T-cell activation, proliferation, and Th1 differentiation in the lungs. BCG infection caused greater distribution of airway OVA to pulmonary dendritic cells and enhanced presentation of OVA peptide by lung CD11c+ cells. Together, these data suggest that an existing pulmonary mycobacterial infection alters the phenotype of lung dendritic cells so that they can activate antigen-specific naive CD4+ T cells in the lungs in response to airway antigen challenge.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Pulmão/imunologia , Ativação Linfocitária/imunologia , Mycobacterium bovis/patogenicidade , Ovalbumina/administração & dosagem , Tuberculose Pulmonar/imunologia , Transferência Adotiva , Animais , Antígenos/administração & dosagem , Antígenos/imunologia , Antígeno CD11c/metabolismo , Células Dendríticas/imunologia , Feminino , Pulmão/citologia , Linfonodos/citologia , Linfonodos/imunologia , Mediastino , Camundongos , Camundongos Endogâmicos BALB C , Ovalbumina/imunologia , Células Th1/imunologia , Tuberculose Pulmonar/microbiologiaRESUMO
The role of type I interferon (IFN-alphabeta) in modulating innate or adaptive immune responses against mycobacterial infection in the lung is unclear. In this study we investigated the susceptibility of IFN-alphabeta-receptor-deficient (IFN-alphabetaR-/-) mice to pulmonary infection with aerosolized Mycobacterium bovis bacillus Calmette-Guérin (BCG). During early infection (2-3 weeks), enhanced growth of BCG was measured in the lungs of IFN-alphabetaR-/- mice compared to wild-type mice. However, during late infection the burden of BCG was similar in the lungs of IFN-alphabetaR-/- and wild-type mice. Although control of BCG growth was delayed, recruitment and activation of T and natural killer cells, production of IFN-gamma, and cytokine expression were all similar in wild-type and IFN-alphabetaR-/- mice. However, decreased expression of nitric oxide in bronchoalveolar lavage fluids from IFN-alphabetaR-/- mice correlated with enhanced growth of BCG. Bone marrow-derived macrophages from IFN-alphabetaR-/- mice also produced less nitric oxide following infection with BCG in vitro. These findings suggest that IFN-alphabeta contributes to innate immunity to pulmonary mycobacterial infection by augmenting production of nitric oxide.
Assuntos
Proteínas de Membrana/imunologia , Mycobacterium bovis , Receptores de Interferon/imunologia , Tuberculose Pulmonar/imunologia , Animais , Líquido da Lavagem Broncoalveolar/imunologia , Células Cultivadas , Feminino , Imunidade Inata , Interferon gama/biossíntese , Células Matadoras Naturais/imunologia , Pulmão/imunologia , Ativação Linfocitária/imunologia , Macrófagos/metabolismo , Masculino , Proteínas de Membrana/deficiência , Camundongos , Camundongos Knockout , Mycobacterium bovis/crescimento & desenvolvimento , Óxido Nítrico/metabolismo , Receptor de Interferon alfa e beta , Receptores de Interferon/deficiência , Subpopulações de Linfócitos T/imunologia , Tuberculose Pulmonar/microbiologia , Tuberculose Pulmonar/prevenção & controleRESUMO
The genetic region of difference 1 (RD1) in Mycobacterium tuberculosis has recently been hypothesized to encode for proteins that are cytotoxic to the host cell in nature. We demonstrate here that while M. tuberculosis grew progressively in the lungs of gene disrupted mice (GKO) unable to produce interferon-gamma (IFN-gamma), similar mice infected instead with M. bovis bacillus Calmette-Guérin (BCG) reproducibly exhibited an obvious slowing of the disease after about 20 days. Closer examination of BCG-infected GKO mice showed a florid granulomatous inflammation in the lungs, whereas similar mice infected with M. tuberculosis exhibited wholesale progressive necrosis. In the BCG-infected GKO mice large numbers of activated effector T cells, some strongly positive for the cytokine tumour necrosis factor, as well as activated natural killer cells accumulated in the lungs. To further test the hypothesis that the differences observed were directly associated with the loss of the RD1 region, it was then shown that a mutant of M. tuberculosis lacking RD1 grew progressively in both normal and GKO mice but failed to induce any degree of necrosis in either animal despite reaching similar levels in the lungs. However, when mice were infected with this mutant, in which the RD1 region had been restored by complementation, wholesale necrosis of the lungs again occurred. These data support the hypothesis that proteins encoded in the RD1 region are a major cause of necrosis and contribute significantly to the pathogenesis of the disease.
Assuntos
Interferon gama/imunologia , Pulmão/patologia , Mycobacterium bovis/patogenicidade , Mycobacterium tuberculosis/patogenicidade , Tuberculose/imunologia , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Movimento Celular/imunologia , Progressão da Doença , Feminino , Genes Bacterianos , Interferon gama/deficiência , Interferon gama/genética , Pulmão/microbiologia , Ativação Linfocitária/imunologia , Ativação de Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mycobacterium bovis/genética , Mycobacterium bovis/crescimento & desenvolvimento , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/crescimento & desenvolvimento , Necrose , Tuberculose/microbiologia , VirulênciaRESUMO
The importance in vivo of P2X7 receptors in control of virulent Mycobacterium tuberculosis was examined in a low-dose aerosol infection mouse model. P2X7(-/-) mice controlled infection in lungs as well as wild-type mice, suggesting that the P2X7 receptor is not required for control of pulmonary M. tuberculosis infection.
Assuntos
Mycobacterium tuberculosis/patogenicidade , Receptores Purinérgicos P2/metabolismo , Tuberculose Pulmonar/imunologia , Animais , Apresentação de Antígeno , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Pulmão/imunologia , Pulmão/microbiologia , Linfonodos/imunologia , Linfonodos/microbiologia , Macrófagos/imunologia , Macrófagos/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Receptores Purinérgicos P2X7 , Tuberculose Pulmonar/microbiologiaRESUMO
OBJECTIVE: To review the literature regarding long-term prophylaxis of spontaneous bacterial peritonitis (SBP) in patients with cirrhosis. DATA SOURCES: A MEDLINE (1967-September 2004) and bibliographic search of the English-language literature was conducted using the search terms spontaneous bacterial peritonitis, cirrhosis, antimicrobial, and prophylaxis. DATA SYNTHESIS: Long-term antimicrobial prophylaxis has been shown to decrease recurrent SBP in cirrhotics with a prior episode. Prophylaxis in patients with low ascitic fluid protein has also been shown to reduce the incidence of SBP; however, studies are too in-homogeneous to identify subgroups that benefit the most. CONCLUSIONS: Long-term antimicrobial therapy should be considered for secondary prophylaxis of SBP. Studies should be done to confirm this benefit and identify subsets of patients with low ascitic fluid protein who clearly benefit.
Assuntos
Antibacterianos/uso terapêutico , Ascite/complicações , Infecções Bacterianas/prevenção & controle , Cirrose Hepática/complicações , Peritonite/prevenção & controle , Infecções Bacterianas/mortalidade , Ensaios Clínicos como Assunto , Humanos , Peritonite/etiologia , Peritonite/microbiologia , PrognósticoRESUMO
Alveolar macrophages constitute a primary defense against Mycobacterium tuberculosis, but they are unable to control M. tuberculosis without acquired T-cell immunity. This study determined the antigen-presenting cell function of murine alveolar macrophages and the ability of the model mycobacterium, Mycobacterium bovis BCG, to modulate it. The majority (80 to 85%) of alveolar macrophages expressed both CD80 (B7.1) and CD11c, and 20 to 30% coexpressed major histocompatibility complex II (MHC-II). Gamma interferon (IFN-gamma) enhanced MHC-II but not B7.1 expression. Naive or IFN-gamma-treated alveolar macrophages did not express CD86 (B7.2), CD11b, Mac-3, CD40, or F4/80. M. bovis BCG and the 19-kDa mycobacterial lipoprotein inhibited IFN-gamma-regulated MHC-II expression on alveolar macrophages, and inhibition was dependent on Toll-like receptor 2. The inhibition of MHC-II expression by the 19-kDa lipoprotein was associated with decreased presentation of soluble antigen to T cells. Thus, susceptibility to tuberculosis may result from the ability of mycobacteria to interfere with MHC-II expression and antigen presentation by alveolar macrophages.