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1.
Infect Immun ; 92(4): e0001824, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38514468

RESUMO

Borrelia burgdorferi, the spirochetal agent of Lyme disease, utilizes a variety of strategies to evade and suppress the host immune response, which enables it to chronically persist in the host. The resulting immune response is characterized by unusually strong IgM production and a lack of long-term protective immunity. Previous studies in mice have shown that infection with B. burgdorferi also broadly suppresses host antibody responses against unrelated antigens. Here, we show that mice infected with B. burgdorferi and concomitantly immunized with recombinant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein had an abrogated antibody response to the immunization. To further define how long this humoral immune suppression lasts, mice were immunized at 2, 4, and 6 weeks post-infection. Suppression of host antibody production against the SARS-CoV-2 spike protein peaked at 2 weeks post-infection but continued for all timepoints measured. Antibody responses against the SARS-CoV-2 spike protein were also assessed following antibiotic treatment to determine whether this immune suppression persists or resolves following clearance of B. burgdorferi. Host antibody production against the SARS-CoV-2 spike protein returned to baseline following antibiotic treatment; however, anti-SARS-CoV-2 IgM remained high, comparable to levels found in B. burgdorferi-infected but untreated mice. Thus, our data demonstrate restored IgG responses following antibiotic treatment but persistently elevated IgM levels, indicating lingering effects of B. burgdorferi infection on the immune system following treatment.


Assuntos
Borrelia burgdorferi , Doença de Lyme , Glicoproteína da Espícula de Coronavírus , Camundongos , Humanos , Animais , Imunidade Humoral , Imunoglobulina M , Antibacterianos , Anticorpos Antibacterianos
2.
J Infect Dis ; 224(8): 1394-1397, 2021 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-33588433

RESUMO

Coadministration of human secretory IgA (sIgA) together with subtherapeutic vancomycin enhanced survival in the Clostridioides difficile infection (CDI) hamster model. Vancomycin (5 or 10 mg/kg × 5 days) plus healthy donor plasma sIgA/monomeric IgA (TID × 21 days) or hyperimmune sIgA/monomeric IgA (BID × 13 days) enhanced survival. Survival was improved compared to vancomycin alone, P = .018 and .039 by log-rank Mantel-Cox, for healthy and hyperimmune sIgA, respectively. Passive immunization with sIgA (recombinant human secretory component plus IgA dimer/polymer from pooled human plasma) can be administered orally and prevents death in a partially treated CDI hamster model.


Assuntos
Antibacterianos/uso terapêutico , Clostridioides difficile , Infecções por Clostridium/terapia , Imunoglobulina A Secretora/uso terapêutico , Imunoterapia/métodos , Vancomicina/uso terapêutico , Animais , Cricetinae , Humanos , Imunoglobulina A , Fatores Imunológicos
3.
Antimicrob Agents Chemother ; 65(8): e0055221, 2021 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-34001510

RESUMO

There is an urgent need for oral agents to combat resistant Gram-negative pathogens. Here, we describe the characterization of VNRX-5236, a broad-spectrum boronic acid ß-lactamase inhibitor (BLI), and its orally bioavailable etzadroxil prodrug, VNRX-7145. VNRX-7145 is being developed in combination with ceftibuten, an oral cephalosporin, to combat strains of Enterobacterales expressing extended-spectrum ß-lactamases (ESBLs) and serine carbapenemases. VNRX-5236 is a reversible covalent inhibitor of serine ß-lactamases, with inactivation efficiencies on the order of 104 M-1 · sec-1, and prolonged active site residence times (t1/2, 5 to 46 min). The spectrum of inhibition includes Ambler class A ESBLs, class C cephalosporinases, and class A and D carbapenemases (KPC and OXA-48, respectively). Rescue of ceftibuten by VNRX-5236 (fixed at 4 µg/ml) in isogenic strains of Escherichia coli expressing class A, C, or D ß-lactamases demonstrated an expanded spectrum of activity relative to oral comparators, including investigational penems, sulopenem, and tebipenem. VNRX-5236 rescued ceftibuten activity in clinical isolates of Enterobacterales expressing ESBLs (MIC90, 0.25 µg/ml), KPCs (MIC90, 1 µg/ml), class C cephalosporinases (MIC90, 1 µg/ml), and OXA-48-type carbapenemases (MIC90, 1 µg/ml). Frequency of resistance studies demonstrated a low propensity for recovery of resistant variants at 4× the MIC of the ceftibuten/VNRX-5236 combination. In vivo, whereas ceftibuten alone was ineffective (50% effective dose [ED50], >128 mg/kg), ceftibuten/VNRX-7145 administered orally protected mice from lethal septicemia caused by Klebsiella pneumoniae producing KPC carbapenemase (ED50, 12.9 mg/kg). The data demonstrate potent, broad-spectrum rescue of ceftibuten activity by VNRX-5236 in clinical isolates of cephalosporin-resistant and carbapenem-resistant Enterobacterales.


Assuntos
Cefalosporinas , Inibidores de beta-Lactamases , Animais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Proteínas de Bactérias , Carbapenêmicos/farmacologia , Ceftibuteno , Cefalosporinas/farmacologia , Camundongos , Testes de Sensibilidade Microbiana , Serina , Inibidores de beta-Lactamases/farmacologia , beta-Lactamases/genética
4.
BMC Microbiol ; 20(1): 27, 2020 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-32024477

RESUMO

BACKGROUND: Clostridioides difficile infections have become more frequently diagnosed and associated with greater disease severity, which has resulted in an increase burden on the healthcare system. These increases are attributed to the increased prevalence of hypervirulent strains encompassing select ribotypes. These epidemic ribotypes were characterized as hypervirulent due to higher in vitro spore and toxin production, as well as increased incidence, severity and mortality within patients. However, it is unclear whether epidemic ribotypes are truly more virulent than non-epidemic ribotypes in vivo. Furthermore, there is conflicting evidence about the ability of a strain's in vitro phenotype to be predictive of their in vivo virulence. The goals of the current studies were to determine if epidemic ribotypes are more virulent than other ribotypes in animal models, and whether the in vitro virulence phenotype of an isolate or ribotype predict in vivo virulence. RESULTS: To determine if epidemic strains were truly more virulent than other non-epidemic strains, the in vivo virulence of 13 C. difficile isolates (7 non-epidemic and 6 epidemic ribotype isolates) were determined in murine and hamster models of CDI. The isolates of epidemic ribotype of C. difficile were found to be more virulent in both the murine and hamster models than non-epidemic isolates. In particular, the group of epidemic ribotypes of C. difficile had lower LD50 values in hamsters. The increased severity of disease was associated with higher levels of Toxin A and Toxin B production found in fecal samples, but not numbers of organisms recovered. The isolates were further characterized for their in vitro virulence phenotypes, e.g. toxin production, growth rates, spore formation and adherence of spores to intestinal epithelial cell lines. Although there were higher levels of toxins produced and greater adherence for the group of epidemic ribotypes, the in vitro profiles of individual isolates were not always predictive of their in vivo virulence. CONCLUSIONS: Overall, the group of epidemic ribotypes of C. difficile were more virulent in vivo despite individual isolates having similar phenotypes to the non-epidemic isolates in vitro.


Assuntos
Clostridioides difficile/classificação , Clostridioides difficile/patogenicidade , Infecções por Clostridium/mortalidade , Ribotipagem/métodos , Animais , Aderência Bacteriana , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Células CACO-2 , Clostridioides difficile/genética , Infecções por Clostridium/epidemiologia , Infecções por Clostridium/microbiologia , Cricetinae , Modelos Animais de Doenças , Enterotoxinas/metabolismo , Epidemias , Fezes/química , Feminino , Humanos , Dose Letal Mediana , Masculino , Camundongos , Mortalidade , Virulência
5.
Artigo em Inglês | MEDLINE | ID: mdl-30670434

RESUMO

Lantibiotics present an attractive scaffold for the development of novel antibiotics. We report here a novel lantibiotic for the treatment of Clostridium difficile infection. The lead compounds were selected from a library of over 700 single- and multiple-substitution variants of the lantibiotic mutacin 1140 (MU1140). The best performers in vitro and in vivo were further used to challenge Golden Syrian hamsters orally in a Golden Syrian hamster model of Clostridium difficile-associated disease (CDAD) in a dose-response format, resulting in the selection of OG716 as the lead compound. This lantibiotic was characterized by a 50% effective dose of 23.85 mg/kg of body weight/day (10.97 µmol/kg/day) in this model. Upon oral administration of the maximum feasible dose (≥1,918 mg/kg/day), no observable toxicities or side effects were noted, and no effect on intestinal motility was observed. Compartmentalization to the gastrointestinal tract was confirmed. MU1140-derived variants offer a large pipeline for the development of novel antibiotics for the treatment of several indications and are particularly attractive considering their novel mechanism of action. Based on the currently available data, OG716 has an acceptable profile for further development for the treatment of CDAD.


Assuntos
Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Infecções por Clostridium/tratamento farmacológico , Administração Oral , Animais , Antibacterianos/administração & dosagem , Antibacterianos/efeitos adversos , Antibacterianos/química , Bacteriocinas/administração & dosagem , Bacteriocinas/efeitos adversos , Bacteriocinas/química , Disponibilidade Biológica , Ceco/microbiologia , Infecções por Clostridium/mortalidade , Contagem de Colônia Microbiana , Relação Dose-Resposta a Droga , Feminino , Esvaziamento Gástrico/efeitos dos fármacos , Masculino , Dose Máxima Tolerável , Mesocricetus , Ratos Wistar
6.
Artigo em Inglês | MEDLINE | ID: mdl-31636067

RESUMO

Fluoroquinolone treatments induce dysbiosis of the intestinal microbiota, resulting in loss of resistance to colonization by exogenous bacteria such as Clostridioides difficile that may cause severe diarrhea in humans and lethal infection in hamsters. We show here that DAV131A, a charcoal-based adsorbent, decreases the intestinal levels of the fluoroquinolone antibiotics levofloxacin and ciprofloxacin in hamsters, protects their intestinal microbiota, and prevents lethal infection by C. difficile.


Assuntos
Carvão Vegetal/administração & dosagem , Clostridioides difficile , Infecções por Clostridium/prevenção & controle , Administração Oral , Adsorção , Animais , Antibacterianos/efeitos adversos , Antibacterianos/farmacocinética , Ciprofloxacina/efeitos adversos , Ciprofloxacina/farmacocinética , Clostridioides difficile/patogenicidade , Modelos Animais de Doenças , Disbiose/induzido quimicamente , Disbiose/metabolismo , Disbiose/prevenção & controle , Fluoroquinolonas/efeitos adversos , Fluoroquinolonas/farmacocinética , Microbioma Gastrointestinal/efeitos dos fármacos , Levofloxacino/efeitos adversos , Levofloxacino/farmacocinética , Masculino , Mesocricetus
7.
Artigo em Inglês | MEDLINE | ID: mdl-29038270

RESUMO

The recently approved combination of meropenem and vaborbactam (Vabomere) is highly active against Gram-negative pathogens, especially Klebsiella pneumoniae carbapenemase (KPC)-producing, carbapenem-resistant Enterobacteriaceae We evaluated the efficacy of meropenem-vaborbactam against three clinically relevant isolates in a murine pyelonephritis model. The data indicate that the combination of meropenem and vaborbactam significantly increased bacterial killing compared to that with the untreated controls. These data suggest that this combination may have utility in the treatment of complicated urinary tract infections due to KPC-producing, carbapenem-resistant Enterobacteriaceae.


Assuntos
Antibacterianos/uso terapêutico , Ácidos Borônicos/uso terapêutico , Enterobacteriáceas Resistentes a Carbapenêmicos/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Klebsiella pneumoniae/efeitos dos fármacos , Meropeném/uso terapêutico , Pielonefrite/tratamento farmacológico , Infecções Urinárias/tratamento farmacológico , Inibidores de beta-Lactamases/uso terapêutico , Animais , Proteínas de Bactérias/metabolismo , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Modelos Animais de Doenças , Combinação de Medicamentos , Humanos , Klebsiella pneumoniae/isolamento & purificação , Klebsiella pneumoniae/metabolismo , Camundongos , Testes de Sensibilidade Microbiana , Pielonefrite/microbiologia , Infecções Urinárias/microbiologia , beta-Lactamases/metabolismo
8.
Artigo em Inglês | MEDLINE | ID: mdl-30061286

RESUMO

Antibiotic disruption of the intestinal microbiota favors colonization by Clostridium difficile Using a charcoal-based adsorbent to decrease intestinal antibiotic concentrations, we studied the relationship between antibiotic concentrations in feces and the intensity of dysbiosis and quantified the link between this intensity and mortality. We administered either moxifloxacin (n = 70) or clindamycin (n = 60) to hamsters by subcutaneous injection from day 1 (D1) to D5 and challenged them with a C. difficile toxigenic strain at D3 Hamsters received various doses of a charcoal-based adsorbent, DAV131A, to modulate intestinal antibiotic concentrations. Gut dysbiosis was evaluated at D0 and D3 using diversity indices determined from 16S rRNA gene profiling. Survival was monitored until D16 We analyzed the relationship between fecal antibiotic concentrations and dysbiosis at the time of C. difficile challenge and studied their capacity to predict subsequent death of the animals. Increasing doses of DAV131A reduced fecal concentrations of both antibiotics, lowered dysbiosis, and increased survival from 0% to 100%. Mortality was related to the level of dysbiosis (P < 10-5 for the change of Shannon index in moxifloxacin-treated animals and P < 10-9 in clindamycin-treated animals). The Shannon diversity index and unweighted UniFrac distance best predicted death, with areas under the receiver operating curve (ROC) of 0.89 (95% confidence interval [CI], 0.82, 0.95) and 0.95 (0.90, 0.98), respectively. Altogether, moxifloxacin and clindamycin disrupted the diversity of the intestinal microbiota with a dependency on the DAV131A dose; mortality after C. difficile challenge was related to the intensity of dysbiosis in similar manners with the two antibiotics.


Assuntos
Antibacterianos/efeitos adversos , Infecções por Clostridium/tratamento farmacológico , Infecções por Clostridium/mortalidade , Disbiose/induzido quimicamente , Animais , Antibacterianos/uso terapêutico , Clindamicina/uso terapêutico , Clostridioides difficile/efeitos dos fármacos , Clostridioides difficile/patogenicidade , Cricetinae , Disbiose/mortalidade , Microbioma Gastrointestinal/efeitos dos fármacos , Masculino , Mesocricetus , Moxifloxacina/uso terapêutico
9.
Artigo em Inglês | MEDLINE | ID: mdl-28739791

RESUMO

Lowering the gut exposure to antibiotics during treatments can prevent microbiota disruption. We evaluated the effects of an activated charcoal-based adsorbent, DAV131A, on the fecal free moxifloxacin concentration and mortality in a hamster model of moxifloxacin-induced Clostridium difficile infection. A total of 215 hamsters receiving moxifloxacin subcutaneously (day 1 [D1] to D5) were orally infected at D3 with C. difficile spores. They received various doses (0 to 1,800 mg/kg of body weight/day) and schedules (twice a day [BID] or three times a day [TID]) of DAV131A (D1 to D8). Moxifloxacin concentrations and C. difficile counts were determined at D3, and mortality was determined at D12 We compared mortality rates, moxifloxacin concentrations, and C. difficile counts according to DAV131A regimen and modeled the links between DAV131A regimen, moxifloxacin concentration, and mortality. All hamsters that received no DAV131A died, but none of those that received 1,800 mg/kg/day died. Significant dose-dependent relationships between DAV131A dose and (i) mortality, (ii) moxifloxacin concentration, and (iii) C. difficile count were evidenced. Mathematical modeling suggested that (i) lowering the moxifloxacin concentration at D3, which was 58 µg/g (95% confidence interval [CI] = 50 to 66 µg/g) without DAV131A, to 17 µg/g (14 to 21 µg/g) would reduce mortality by 90%; and (ii) this would be achieved with a daily DAV131A dose of 703 mg/kg (596 to 809 mg/kg). In this model of C. difficile infection, DAV131A reduced mortality in a dose-dependent manner by decreasing the fecal free moxifloxacin concentration.


Assuntos
Clostridioides difficile/patogenicidade , Infecções por Clostridium/induzido quimicamente , Disbiose/induzido quimicamente , Enterocolite Pseudomembranosa/induzido quimicamente , Fluoroquinolonas/efeitos adversos , Microbioma Gastrointestinal/efeitos dos fármacos , Trato Gastrointestinal/efeitos dos fármacos , Animais , Carvão Vegetal/farmacologia , Infecções por Clostridium/tratamento farmacológico , Cricetinae , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Enterocolite Pseudomembranosa/tratamento farmacológico , Enterocolite Pseudomembranosa/mortalidade , Fluoroquinolonas/farmacologia , Trato Gastrointestinal/microbiologia , Moxifloxacina
10.
Artigo em Inglês | MEDLINE | ID: mdl-28167541

RESUMO

Based upon knowledge of the hydrolytic profile of major ß-lactamases found in Gram-negative bacteria, we tested the efficacy of the combination of ceftazidime-avibactam (CAZ-AVI) with aztreonam (ATM) against carbapenem-resistant enteric bacteria possessing metallo-ß-lactamases (MBLs). Disk diffusion and agar-based antimicrobial susceptibility testing were initially performed to determine the in vitro efficacy of a unique combination of CAZ-AVI and ATM against 21 representative Enterobacteriaceae isolates with a complex molecular background that included blaIMP, blaNDM, blaOXA-48, blaCTX-M, blaAmpC, and combinations thereof. Time-kill assays were conducted, and the in vivo efficacy of this combination was assessed in a murine neutropenic thigh infection model. By disk diffusion assay, all 21 isolates were resistant to CAZ-AVI alone, and 19/21 were resistant to ATM. The in vitro activity of CAZ-AVI in combination with ATM against diverse Enterobacteriaceae possessing MBLs was demonstrated in 17/21 isolates, where the zone of inhibition was ≥21 mm. All isolates demonstrated a reduction in CAZ-AVI agar dilution MICs with the addition of ATM. At 2 h, time-kill assays demonstrated a ≥4-log10-CFU decrease for all groups that had CAZ-AVI with ATM (8 µg/ml) added, compared to the group treated with CAZ-AVI alone. In the murine neutropenic thigh infection model, an almost 4-log10-CFU reduction was noted at 24 h for CAZ-AVI (32 mg/kg every 8 h [q8h]) plus ATM (32 mg/kg q8h) versus CAZ-AVI (32 mg/kg q8h) alone. The data presented herein require us to carefully consider this new therapeutic combination to treat infections caused by MBL-producing Enterobacteriaceae.


Assuntos
Antibacterianos/farmacologia , Compostos Azabicíclicos/farmacologia , Aztreonam/farmacologia , Ceftazidima/farmacologia , Infecções por Enterobacteriaceae/tratamento farmacológico , Enterobacteriaceae/efeitos dos fármacos , Animais , Contagem de Colônia Microbiana , Ciclofosfamida , Esquema de Medicação , Combinação de Medicamentos , Quimioterapia Combinada , Enterobacteriaceae/enzimologia , Enterobacteriaceae/genética , Enterobacteriaceae/crescimento & desenvolvimento , Infecções por Enterobacteriaceae/microbiologia , Feminino , Expressão Gênica , Humanos , Infecções por Klebsiella/complicações , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/crescimento & desenvolvimento , Camundongos , Testes de Sensibilidade Microbiana , Neutropenia/induzido quimicamente , Neutropenia/complicações , Neutropenia/tratamento farmacológico , Neutropenia/microbiologia , Plasmídeos/química , Plasmídeos/metabolismo , Infecções dos Tecidos Moles/complicações , Infecções dos Tecidos Moles/tratamento farmacológico , Infecções dos Tecidos Moles/microbiologia , Coxa da Perna , Resistência beta-Lactâmica/efeitos dos fármacos , Resistência beta-Lactâmica/genética , beta-Lactamases/genética , beta-Lactamases/metabolismo
11.
J Immunol ; 193(3): 1353-63, 2014 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-24973442

RESUMO

Mycoplasmas are a common cause of pneumonia in humans and animals, and attempts to create vaccines have not only failed to generate protective host responses, but they have exacerbated the disease. Mycoplasma pulmonis causes a chronic inflammatory lung disease resulting from a persistent infection, similar to other mycoplasma respiratory diseases. Using this model, Th1 subsets promote resistance to mycoplasma disease and infection, whereas Th2 responses contribute to immunopathology. The purpose of the present study was to evaluate the capacity of cytokine-differentiated dendritic cell (DC) populations to influence the generation of protective and/or pathologic immune responses during M. pulmonis respiratory disease in BALB/c mice. We hypothesized that intratracheal inoculation of mycoplasma Ag-pulsed bone marrow-derived DCs could result in the generation of protective T cell responses during mycoplasma infection. However, intratracheal inoculation (priming) of mice with Ag-pulsed DCs resulted in enhanced pathology in the recipient mice when challenged with mycoplasma. Inoculation of immunodeficient SCID mice with Ag-pulsed DCs demonstrated that this effect was dependent on lymphocyte responses. Similar results were observed when mice were primed with Ag-pulsed pulmonary, but not splenic, DCs. Lymphocytes generated in uninfected mice after the transfer of either Ag-pulsed bone marrow-derived DCs or pulmonary DCs were shown to be IL-13(+) Th2 cells, known to be associated with immunopathology. Thus, resident pulmonary DCs most likely promote the development of immunopathology in mycoplasma disease through the generation of mycoplasma-specific Th2 responses. Vaccination strategies that disrupt or bypass this process could potentially result in a more effective vaccination.


Assuntos
Antígenos de Bactérias/administração & dosagem , Células da Medula Óssea/imunologia , Células Dendríticas/imunologia , Pulmão/imunologia , Mycoplasma pulmonis/imunologia , Pneumonia por Mycoplasma/imunologia , Células Th2/imunologia , Administração Intranasal , Animais , Células da Medula Óssea/microbiologia , Células da Medula Óssea/patologia , Células Dendríticas/patologia , Células Dendríticas/transplante , Feminino , Intubação Intratraqueal , Pulmão/microbiologia , Pulmão/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos SCID , Mycoplasma pulmonis/patogenicidade , Pneumonia por Mycoplasma/microbiologia , Pneumonia por Mycoplasma/patologia , Células Th2/patologia , Células Th2/transplante
12.
Antimicrob Agents Chemother ; 58(10): 5714-8, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25022586

RESUMO

SMT19969 [2,2'-bis(4-pyridyl)3H,3'-H 5,5-bibenzimidazole] is a novel narrow-spectrum nonabsorbable antibiotic currently in development for the treatment of Clostridium difficile infection. The comparative activities of SMT19969 and vancomycin against nonepidemic and epidemic strains of C. difficile were studied in an established hamster model. Against nonepidemic (VA11) strains, the survival rates of SMT19969-treated animals ranged from 80% to 95%. Vancomycin exhibited 100% protection during treatment, with relapse observed starting on day 9 and 50% survival at day 20. At 50 mg/kg of body weight, SMT19969 administered orally once daily for 5 days provided full protection of treated animals on the dosing days and through day 12 against epidemic strains. Vancomycin also protected during the dosing interval, but apparent relapse occurred earlier, starting on day 11. SMT19969 exhibited excellent in vitro activity, with MICs of 0.25 µg/ml for all isolates. The MICs for vancomycin were 2- to 4-fold higher at ≤0.5 to 1 µg/ml. All plasma sample concentrations of SMT19969 were below the limit of quantification (25 ng/ml) at all time points, consistent with the reported lack of bioavailability of the compound. Cecal concentrations were significantly above the MIC (ranging from 96 µg/ml to 172 µg/ml).


Assuntos
Antibacterianos/uso terapêutico , Clostridioides difficile/efeitos dos fármacos , Clostridioides difficile/patogenicidade , Infecções por Clostridium/tratamento farmacológico , Animais , Infecções por Clostridium/microbiologia , Cricetinae , Masculino , Mesocricetus , Metronidazol/uso terapêutico , Testes de Sensibilidade Microbiana , Vancomicina/uso terapêutico
13.
mBio ; 15(9): e0148324, 2024 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-39082787

RESUMO

Cryptococcosis, caused by fungi of the genus Cryptococcus, manifests in a broad range of clinical presentations, including severe pneumonia and disease of the central nervous system (CNS) and other tissues (bone and skin). Immune deficiency or development of overexuberant inflammatory responses can result in increased susceptibility or host damage, respectively, during fungal encounters. Leukotrienes help regulate inflammatory responses against fungal infections. Nevertheless, studies showed that Cryptococcus exploits host 5-lipoxygenase (5-LO), an enzyme central to the metabolism of arachidonic acid into leukotrienes, to facilitate transmigration across the brain-blood barrier. To investigate the impact of host 5-LO on the development of protective host immune responses and mortality during cryptococcosis, wild-type (C57BL/6) and 5-lipoxygenase-deficient (5-LO-/-) mice were given experimental pulmonary and systemic Cryptococcus sp., infections. Our results showed that 5-LO-/- mice exhibited reduced pathology and better disease outcomes (i.e., no mortality or signs associated with cryptococcal meningoencephalitis) following pulmonary infection with C. deneoformans, despite having detectable yeast in the brain tissues. In contrast, C57BL/6 mice exhibited classical signs associated with cryptococcal meningoencephalitis. Additionally, brain tissues of 5-LO-/- mice exhibited lower levels of cytokines (CCL2 and CCL3) clinically associated with Cryptococcus-related immune reconstitution inflammatory syndrome (C-IRIS). In a systemic mouse model of cryptococcosis, 5-LO-/- mice and those treated with a Federal Drug Administration (FDA)-approved 5-LO synthesis inhibitor, zileuton, displayed significantly reduced mortality compared to C57BL/6 infected mice. These results suggest that therapeutics designed to inhibit host 5-LO signaling could reduce disease pathology and mortality associated with cryptococcal meningoencephalitis. IMPORTANCE: Cryptococcosis is a mycosis with worldwide distribution and has a broad range of clinical manifestations, including diseases of the CNS. Globally, there is an estimated 179,000 cases of cryptococcal meningitis, resulting in approximately 112,000 fatalities per annum and 19% of AIDS-related deaths. Understanding how host immune responses are modulated during cryptococcosis is central to mitigating the morbidity and mortality associated with cryptococcosis. Leukotrienes (LTs) have been shown to modulate inflammatory responses during infection. In this study, we show that mice deficient in 5-lipoxygenase (5-LO), an enzyme central to the metabolism of arachidonic acid into leukotrienes, exhibit reduced pathology, disease, and neurological signs associated with cryptococcal meningitis. Additionally, mice given an experimental cryptococcal infection and subsequently treated with an FDA-approved 5-LO synthesis inhibitor exhibited significantly reduced mortality rates. These results suggest that therapeutics designed to inhibit host 5-LO activity could significantly reduce pathology and mortality rates associated with cryptococcal meningitis.


Assuntos
Araquidonato 5-Lipoxigenase , Criptococose , Meningoencefalite , Camundongos Endogâmicos C57BL , Animais , Camundongos , Araquidonato 5-Lipoxigenase/metabolismo , Araquidonato 5-Lipoxigenase/genética , Araquidonato 5-Lipoxigenase/deficiência , Meningoencefalite/microbiologia , Meningoencefalite/imunologia , Meningoencefalite/mortalidade , Criptococose/imunologia , Criptococose/microbiologia , Criptococose/mortalidade , Camundongos Knockout , Inflamação , Hidroxiureia/farmacologia , Hidroxiureia/análogos & derivados , Modelos Animais de Doenças , Inibidores de Lipoxigenase/farmacologia , Feminino , Cryptococcus
14.
Antimicrob Agents Chemother ; 57(5): 2182-90, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23459481

RESUMO

This study examines the alteration in Staphylococcus aureus gene expression following treatment with the type 2 fatty acid synthesis inhibitor AFN-1252. An Affymetrix array study showed that AFN-1252 rapidly increased the expression of fatty acid synthetic genes and repressed the expression of virulence genes controlled by the SaeRS 2-component regulator in exponentially growing cells. AFN-1252 did not alter virulence mRNA levels in a saeR deletion strain or in strain Newman expressing a constitutively active SaeS kinase. AFN-1252 caused a more pronounced increase in fabH mRNA levels in cells entering stationary phase, whereas the depression of virulence factor transcription was attenuated. The effect of AFN-1252 on gene expression in vivo was determined using a mouse subcutaneous granuloma infection model. AFN-1252 was therapeutically effective, and the exposure (area under the concentration-time curve from 0 to 48 h [AUC(0-48)]) of AFN-1252 in the pouch fluid was comparable to the plasma levels in orally dosed animals. The inhibition of fatty acid biosynthesis by AFN-1252 in the infected pouches was signified by the substantial and sustained increase in fabH mRNA levels in pouch-associated bacteria, whereas depression of virulence factor mRNA levels in the AFN-1252-treated pouch bacteria was not as evident as it was in exponentially growing cells in vitro. The trends in fabH and virulence factor gene expression in the animal were similar to those in slower-growing bacteria in vitro. These data indicate that the effects of AFN-1252 on virulence factor gene expression depend on the physiological state of the bacteria.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Benzofuranos/farmacologia , Enoil-(Proteína de Transporte de Acila) Redutase (NADPH, B-Específica)/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Pironas/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Acetiltransferases/genética , Acetiltransferases/metabolismo , Animais , Antibacterianos/farmacocinética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Benzofuranos/farmacocinética , Enoil-(Proteína de Transporte de Acila) Redutase (NADPH, B-Específica)/genética , Enoil-(Proteína de Transporte de Acila) Redutase (NADPH, B-Específica)/metabolismo , Inibidores Enzimáticos/farmacocinética , Ácidos Graxos/metabolismo , Perfilação da Expressão Gênica , Granuloma/tratamento farmacológico , Granuloma/microbiologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Camundongos , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Pironas/farmacocinética , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
15.
PLoS Pathog ; 7(2): e1001287, 2011 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-21347352

RESUMO

Methicillin-resistant Staphylococcus aureus is estimated to cause more U.S. deaths annually than HIV/AIDS. The emergence of hypervirulent and multidrug-resistant strains has further amplified public health concern and accentuated the need for new classes of antibiotics. RNA degradation is a required cellular process that could be exploited for novel antimicrobial drug development. However, such discovery efforts have been hindered because components of the Gram-positive RNA turnover machinery are incompletely defined. In the current study we found that the essential S. aureus protein, RnpA, catalyzes rRNA and mRNA digestion in vitro. Exploiting this activity, high through-put and secondary screening assays identified a small molecule inhibitor of RnpA-mediated in vitro RNA degradation. This agent was shown to limit cellular mRNA degradation and exhibited antimicrobial activity against predominant methicillin-resistant S. aureus (MRSA) lineages circulating throughout the U.S., vancomycin intermediate susceptible S. aureus (VISA), vancomycin resistant S. aureus (VRSA) and other Gram-positive bacterial pathogens with high RnpA amino acid conservation. We also found that this RnpA-inhibitor ameliorates disease in a systemic mouse infection model and has antimicrobial activity against biofilm-associated S. aureus. Taken together, these findings indicate that RnpA, either alone, as a component of the RNase P holoenzyme, and/or as a member of a more elaborate complex, may play a role in S. aureus RNA degradation and provide proof of principle for RNA catabolism-based antimicrobial therapy.


Assuntos
Anti-Infecciosos/farmacologia , Processamento Pós-Transcricional do RNA/efeitos dos fármacos , RNA Mensageiro/metabolismo , Ribonuclease P/antagonistas & inibidores , Infecções Estafilocócicas/prevenção & controle , Staphylococcus aureus , Animais , Anti-Infecciosos/uso terapêutico , Feminino , Células Hep G2 , Humanos , Camundongos , Modelos Biológicos , Ribonuclease P/fisiologia , Bibliotecas de Moléculas Pequenas/farmacologia , Bibliotecas de Moléculas Pequenas/uso terapêutico , Infecções Estafilocócicas/genética , Infecções Estafilocócicas/patologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo , Staphylococcus aureus/patogenicidade , Vancomicina/farmacologia , Vancomicina/uso terapêutico , Virulência/efeitos dos fármacos , Virulência/genética
16.
Pharmaceutics ; 15(2)2023 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-36839766

RESUMO

Lung metastasis is a leading cause of cancer-related deaths. Here, we show that intranasal delivery of our engineered CpG-coated tumor antigen (Tag)-encapsulated nanoparticles (NPs)-nasal nano-vaccine-significantly reduced lung colonization by intravenous challenge of an extra-pulmonary tumor. Protection against tumor-cell lung colonization was linked to the induction of localized mucosal-associated effector and resident memory T cells as well as increased bronchiolar alveolar lavage-fluid IgA and serum IgG antibody responses. The nasal nano-vaccine-induced T-cell-mediated antitumor mucosal immune response was shown to increase tumor-specific production of IFN-γ and granzyme B by lung-derived CD8+ T cells. These findings demonstrate that our engineered nasal nano-vaccine has the potential to be used as a prophylactic approach prior to the seeding of tumors in the lungs, and thereby prevent overt lung metastases from existing extra pulmonary tumors.

17.
Pharmaceuticals (Basel) ; 17(1)2023 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-38256885

RESUMO

A hallmark of effective cancer treatment is the prevention of tumor reoccurrence and metastasis to distal organs, which are responsible for most cancer deaths. However, primary tumor resection is expected to be curative as most solid tumors have been shown both experimentally and clinically to accelerate metastasis to distal organs including the lungs. In this study, we evaluated the efficacy of our engineered nasal nano-vaccine (CpG-NP-Tag) in reducing accelerated lung metastasis resulting from primary tumor resection. Cytosine-phosphate-guanine oligonucleotide [CpG ODN]-conjugated nanoparticle [NP] encapsulating tumor antigen [Tag] (CpG-NP-Tag) was manufactured and tested in vivo using a syngeneic mouse mammary tumor model following intranasal delivery. We found that our nasal nano-vaccine (CpG-NP-Tag), compared to control NPs administered after primary mammary tumor resection, significantly reduced lung metastasis in female BALB/c mice subjected to surgery (surgery mice). An evaluation of vaccine efficacy in both surgery and non-surgery mice revealed that primary tumor resection reduces CD11b+ monocyte-derived suppressor-like cell accumulation in the lungs, allowing increased infiltration of vaccine-elicited T cells (IFN-γ CD8+ T cells) in the lungs of surgery mice compared to non-surgery mice. These findings suggest that the combination of the target delivery of a nasal vaccine in conjunction with the standard surgery of primary tumors is a plausible adjunctive treatment against the establishment of lung metastasis.

18.
Cell Rep Med ; 4(11): 101253, 2023 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-37918405

RESUMO

Colonization of the gut and airways by pathogenic bacteria can lead to local tissue destruction and life-threatening systemic infections, especially in immunologically compromised individuals. Here, we describe an mRNA-based platform enabling delivery of pathogen-specific immunoglobulin A (IgA) monoclonal antibodies into mucosal secretions. The platform consists of synthetic mRNA encoding IgA heavy, light, and joining (J) chains, packaged in lipid nanoparticles (LNPs) that express glycosylated, dimeric IgA with functional activity in vitro and in vivo. Importantly, mRNA-derived IgA had a significantly greater serum half-life and a more native glycosylation profile in mice than did a recombinantly produced IgA. Expression of an mRNA encoded Salmonella-specific IgA in mice resulted in intestinal localization and limited Peyer's patch invasion. The same mRNA-LNP technology was used to express a Pseudomonas-specific IgA that protected from a lung challenge. Leveraging the mRNA antibody technology as a means to intercept bacterial pathogens at mucosal surfaces opens up avenues for prophylactic and therapeutic interventions.


Assuntos
Mucosa , Nódulos Linfáticos Agregados , Camundongos , Animais , Imunoglobulina A , Anticorpos Monoclonais
19.
J Med Chem ; 65(6): 4481-4495, 2022 03 24.
Artigo em Inglês | MEDLINE | ID: mdl-35175750

RESUMO

TNP-2198, a stable conjugate of a rifamycin pharmacophore and a nitroimidazole pharmacophore, has been designed, synthesized, and evaluated as a novel dual-targeted antibacterial agent for the treatment of microaerophilic and anaerobic bacterial infections. TNP-2198 exhibits greater activity than a 1:1 molar mixture of the parent drugs and exhibits activity against strains resistant to both rifamycins and nitroimidazoles. A crystal structure of TNP-2198 bound to a Mycobacterium tuberculosis RNA polymerase transcription initiation complex reveals that the rifamycin portion of TNP-2198 binds to the rifamycin binding site on RNAP and the nitroimidazole portion of TNP-2198 interacts directly with the DNA template-strand in the RNAP active-center cleft, forming a hydrogen bond with a base of the DNA template strand. TNP-2198 is currently in Phase 2 clinical development for the treatment of Helicobacter pylori infection, Clostridioides difficile infection, and bacterial vaginosis.


Assuntos
Infecções por Helicobacter , Helicobacter pylori , Nitroimidazóis , Rifamicinas , Anaerobiose , RNA Polimerases Dirigidas por DNA , Humanos , Nitroimidazóis/farmacologia
20.
Antimicrob Agents Chemother ; 55(1): 82-5, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21041503

RESUMO

We evaluated the efficacy of NXL104, a novel ß-lactamase inhibitor, in combination with ceftazidime (CAZ) in two murine infection models (septicemia and thigh infection). We chose two KPC-producing Klebsiella pneumoniae strains (VA-361 and VA-406) showing MICs of CAZ of ≥256 µg/ml. Septicemia was induced by the intraperitoneal injection of KPC-producing K. pneumoniae followed 30 min later by a single subcutaneous treatment with CAZ alone or CAZ-NXL104 in ratios of 2:1, 4:1, 8:1, and 16:1. In this model, the median effective doses for 50% (ED(50)) of the animals for CAZ alone versus VA-361 and VA-406 were 1,578 and 709 mg/kg of body weight, respectively. When combined with NXL104 at 2:1, 4:1, 8:1, and 16:1 ratios, the CAZ ED(50)s for VA-361 and VA-406 were reduced to 8.1 and 3.5 mg/kg, 15.1 and 3.8 mg/kg, 16.9 and 7.2 mg/kg, and 29.5 and 12.1 mg/kg, respectively. For thigh infection, neutropenia was induced by the intraperitoneal injection of cyclophosphamide at days -4 and -1 preinfection. Infection was established by the intramuscular injection of KPC-producing K. pneumoniae into the right thigh. Mice were treated 1.5 h postinfection with either CAZ alone or CAZ-NXL104 at constant ratios of 4:1. When thighs were removed at 24 h postinfection, a >2-log CFU reduction was observed for mice treated with CAZ-NXL104 at doses of ≥128:32 mg/kg. In contrast, CAZ doses of ≥1,024 mg/kg were unable to reduce the numbers of CFU. Despite resistance to CAZ and possessing a complex ß-lactamase background, NXL104 combined with CAZ proved to be very effective in murine models of infection due to contemporary highly resistant KPC-producing K. pneumoniae isolates.


Assuntos
Antibacterianos/uso terapêutico , Compostos Azabicíclicos/uso terapêutico , Ceftazidima/uso terapêutico , Infecções por Klebsiella/tratamento farmacológico , Klebsiella pneumoniae/fisiologia , Animais , Modelos Animais de Doenças , Feminino , Camundongos , Testes de Sensibilidade Microbiana , Sepse/tratamento farmacológico
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