scholarly journals Membrane Vesicles Derived fromBordetella bronchiseptica: Active Constituent of a New Vaccine against Infections Caused by This Pathogen

2017 ◽  
Vol 84 (4) ◽  
Author(s):  
D. Bottero ◽  
M. E. Zurita ◽  
M. E. Gaillard ◽  
E. Bartel ◽  
C. Vercellini ◽  
...  
Keyword(s):  
Immune Responses ◽  
Respiratory Tract Infections ◽  
Membrane Vesicles ◽  
Bordetella Bronchiseptica ◽  
Farm Animals ◽  
Human Patient ◽  
Content Type ◽  
Tract Infections

ABSTRACTBordetella bronchiseptica, a Gram-negative bacterium, causes chronic respiratory tract infections in a wide variety of mammalian hosts, including humans (albeit rarely). We recently designedBordetella pertussisandBordetella parapertussisexperimental vaccines based on outer membrane vesicles (OMVs) derived from each pathogen, and we obtained protection against the respective infections in mice. Here, we demonstrated that OMVs derived from virulent-phaseB. bronchiseptica(OMVBbvir+) protected mice against sublethal infections with differentB. bronchisepticastrains, two isolated from farm animals and one isolated from a human patient. In all infections, we observed that theB. bronchisepticaloads were significantly reduced in the lungs of vaccinated animals; the lung-recovered CFU were decreased by ≥4 log units, compared with those detected in the lungs of nonimmunized animals (P< 0.001). In the OMVBbvir+-immunized mice, we detected IgG antibody titers againstB. bronchisepticawhole-cell lysates, along with an immune serum having bacterial killing activity that both recognizedB. bronchisepticalipopolysaccharides and polypeptides such as GroEL and outer membrane protein C (OMPc) and demonstrated an essential protective capacity againstB. bronchisepticainfection, as detected by passivein vivotransfer experiments. Stimulation of cultured splenocytes from immunized mice with OMVBbvir+resulted in interleukin 5 (IL-5), gamma interferon (IFN-γ), and IL-17 production, indicating that the vesicles induced mixed Th2, Th1, and Th17 T-cell immune responses. We detected, by adoptive transfer assays, that spleen cells from OMVBbvir+-immunized mice also contributed to the observed protection againstB. bronchisepticainfection. OMVs from avirulent-phaseB. bronchisepticaand the resulting induced immune sera were also able to protect mice againstB. bronchisepticainfection.IMPORTANCEBordetella bronchiseptica, a Gram-negative bacterium, causes chronic respiratory tract infections in a wide variety of mammalian hosts, including humans (albeit rarely). Several vaccines aimed at preventingB. bronchisepticainfection have been developed and used, but a safe effective vaccine is still needed. The significance and relevance of our research lie in the characterization of the OMVs derived fromB. bronchisepticaas the source of a new experimental vaccine. We demonstrated here that our formulation based on OMVs derived from virulent-phaseB. bronchiseptica(OMVBbvir+) was effective against infections caused byB. bronchisepticaisolates obtained from different hosts (farm animals and a human patient).In vitroandin vivocharacterization of humoral and cellular immune responses induced by the OMVBbvir+vaccine enabled a better understanding of the mechanism of protection necessary to controlB. bronchisepticainfection. Here we also demonstrated that OMVs derived fromB. bronchisepticain the avirulent phase and the corresponding induced humoral immune response were able to protect mice fromB. bronchisepticainfection. This realization provides the basis for the development of novel vaccines not only against the acute stages of the disease but also against stages of the disease or the infectious cycle in which avirulence factors could play a role.

scholarly journals Targeting Tumor Antigens to Secreted Membrane Vesicles In vivo Induces Efficient Antitumor Immune Responses

2008 ◽  
Vol 68 (4) ◽  
pp. 1228-1235 ◽  
Author(s):  
Ingrid S. Zeelenberg ◽  
Matias Ostrowski ◽  
Sophie Krumeich ◽  
Angélique Bobrie ◽  
Carolina Jancic ◽  
...  
Keyword(s):  
Immune Responses ◽  
Tumor Antigens ◽  
Membrane Vesicles

scholarly journals Characterization of the microflora of ventilator-associated respiratory tract infections in patients with severe trauma

2015 ◽  
Vol 20 (1) ◽  
pp. 8-13
Author(s):  
O. A Orlova ◽  
V. G Akimkin
Keyword(s):  
Respiratory Tract ◽  
Respiratory Tract Infections ◽  
Respiratory Infections ◽  
Severe Trauma ◽  
Surgical Intensive Care Unit ◽  
Surgical Intensive Care ◽  
Microbial Associations ◽  
Initial Severity ◽  
Tract Infections

Rationale The relevance of ventilator-associated respiratory tract infections in severe injury patients (SIP) is associated with both features of causative pathogens and the initial severity of the state of patients. Among causative pathogens nosocomial flora is dominant. Purpose - to perform an analysis of the microbiological monitoring of ventilator-associated respiratory tract infections in SIP. The analysis was based on the results of a prospective epidemiological, clinical, and instrumental study of 100 SIP with ventilator-associated respiratory tract infections, stayed in the surgical intensive care unit. The proportion of ventilator-associated respiratory infections in the structure of nosocomial infections in these patients is between 90 - 95%, at that there was revealed the prevalence of nosocomial pneumonia (61%). Ventilator-associated respiratory tract infection most commonly occurs during the first 10 days of mechanical ventilation. The prevailing flora was represented by Gram negative Acinetobacter baumamnnii (40.3 ± 2.1%) and Pseudomonas aeruginosa (38.4% ± 3.2%). Isolated microorganisms possessed multiple antibiotic resistance, with the greatest extent to aminoglycosides - 69.5%, fluoroquinolones - 40.3%, penicillin - 37.6%; cephalosporins (third generation) - 33.8%. There is noted marked preponderance of microbial associations compared with monocultures 57.1 ± 5.3%.

scholarly journals The 8-Pyrrole-Benzothiazinones Are Noncovalent Inhibitors of DprE1 from Mycobacterium tuberculosis

2015 ◽  
Vol 59 (8) ◽  
pp. 4446-4452 ◽  
Author(s):  
Vadim Makarov ◽  
João Neres ◽  
Ruben C. Hartkoorn ◽  
Olga B. Ryabova ◽  
Elena Kazakova ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Nitro Group ◽  
Covalent Bond ◽  
Antimycobacterial Activity ◽  
Content Type ◽  
Sar Studies ◽  
Covalent Bond Formation

ABSTRACT8-Nitro-benzothiazinones (BTZs), such as BTZ043 and PBTZ169, inhibit decaprenylphosphoryl-β-d-ribose 2′-oxidase (DprE1) and display nanomolar bactericidal activity againstMycobacterium tuberculosisin vitro. Structure-activity relationship (SAR) studies revealed the 8-nitro group of the BTZ scaffold to be crucial for the mechanism of action, which involves formation of a semimercaptal bond with Cys387 in the active site of DprE1. To date, substitution of the 8-nitro group has led to extensive loss of antimycobacterial activity. Here, we report the synthesis and characterization of the pyrrole-benzothiazinones PyrBTZ01 and PyrBTZ02, non-nitro-benzothiazinones that retain significant antimycobacterial activity, with MICs of 0.16 μg/ml againstM. tuberculosis. These compounds inhibit DprE1 with 50% inhibitory concentration (IC50) values of <8 μM and present favorablein vitroabsorption-distribution-metabolism-excretion/toxicity (ADME/T) andin vivopharmacokinetic profiles. The most promising compound, PyrBTZ01, did not show efficacy in a mouse model of acute tuberculosis, suggesting that BTZ-mediated killing through DprE1 inhibition requires a combination of both covalent bond formation and compound potency.

scholarly journals Peptidoglycan Sensing Prevents Quiescence and Promotes Quorum-Independent Colony Growth of Uropathogenic Escherichia coli

2020 ◽  
Vol 202 (20) ◽  
Author(s):  
Eric C. DiBiasio ◽  
Hilary J. Ranson ◽  
James R. Johnson ◽  
David C. Rowley ◽  
Paul S. Cohen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Recurrent Infection ◽  
Colony Growth ◽  
Quiescent State ◽  
Content Type ◽  
Tract Infections

ABSTRACT Uropathogenic Escherichia coli (UPEC) is the leading cause of human urinary tract infections (UTIs), and many patients experience recurrent infection after successful antibiotic treatment. The source of recurrent infections may be persistent bacterial reservoirs in vivo that are in a quiescent state and thus are not susceptible to antibiotics. Here, we show that multiple UPEC strains require a quorum to proliferate in vitro with glucose as the carbon source. At low cell density, the bacteria remain viable but enter a quiescent, nonproliferative state. Of the clinical UPEC isolates tested to date, 35% (51/145) enter this quiescent state, including isolates from the recently emerged, multidrug-resistant pandemic lineage ST131 (i.e., strain JJ1886) and isolates from the classic endemic lineage ST73 (i.e., strain CFT073). Moreover, quorum-dependent UPEC quiescence is prevented and reversed by small-molecule proliferants that stimulate colony formation. These proliferation cues include d-amino acid-containing peptidoglycan (PG) tetra- and pentapeptides, as well as high local concentrations of l-lysine and l-methionine. Peptidoglycan fragments originate from the peptidoglycan layer that supports the bacterial cell wall but are released as bacteria grow. These fragments are detected by a variety of organisms, including human cells, other diverse bacteria, and, as we show here for the first time, UPEC. Together, these results show that for UPEC, (i) sensing of PG stem peptide and uptake of l-lysine modulate the quorum-regulated decision to proliferate and (ii) quiescence can be prevented by both intra- and interspecies PG peptide signaling. IMPORTANCE Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections (UTIs). During pathogenesis, UPEC cells adhere to and infiltrate bladder epithelial cells, where they may form intracellular bacterial communities (IBCs) or enter a nongrowing or slowly growing quiescent state. Here, we show in vitro that UPEC strains at low population density enter a reversible, quiescent state by halting division. Quiescent cells resume proliferation in response to sensing a quorum and detecting external signals, or cues, including peptidoglycan tetra- and pentapeptides.

scholarly journals In Vivo Bioluminescent Monitoring of Therapeutic Efficacy and Pharmacodynamic Target Assessment of Antofloxacin against Escherichia coli in a Neutropenic Murine Thigh Infection Model

2017 ◽  
Vol 62 (1) ◽  
Author(s):  
Yu-Feng Zhou ◽  
Meng-Ting Tao ◽  
Yu-Zhang He ◽  
Jian Sun ◽  
Ya-Hong Liu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Subcutaneous Administration ◽  
Free Drug ◽  
Infection Model ◽  
Bioluminescent Imaging ◽  
Time Curve ◽  
Content Type ◽  
E Coli ◽  
Tract Infections

ABSTRACT Antimicrobial resistance among uropathogens has increased the rates of infection-related morbidity and mortality. Antofloxacin is a novel fluoroquinolone with broad-spectrum antibacterial activity against urinary Gram-negative bacilli, such as Escherichia coli. This study monitored the in vivo efficacy of antofloxacin using bioluminescent imaging and determined pharmacokinetic (PK)/pharmacodynamic (PD) targets against E. coli isolates in a neutropenic murine thigh infection model. The PK properties were determined after subcutaneous administration of antofloxacin at 2.5, 10, 40, and 160 mg/kg of body weight. Following thigh infection, the mice were treated with 2-fold-increasing doses of antofloxacin from 2.5 to 80 mg/kg administered every 12 h. Efficacy was assessed by quantitative determination of the bacterial burdens in thigh homogenates and was compared with the bioluminescent density. Antofloxacin demonstrated both static and killing endpoints in relation to the initial burden against all study strains. The PK/PD index area under the concentration-time curve (AUC)/MIC correlated well with efficacy (R 2 = 0.92), and the dose-response relationship was relatively steep, as observed with escalating doses of antofloxacin. The mean free drug AUC/MIC targets necessary to produce net bacterial stasis and 1-log10 and 2-log10 kill for each isolate were 38.7, 66.1, and 147.0 h, respectively. In vivo bioluminescent imaging showed a rapid decrease in the bioluminescent density at free drug AUC/MIC exposures that exceeded the stasis targets. The integration of these PD targets combined with the results of PK studies with humans will be useful in setting optimal dosing regimens for the treatment of urinary tract infections due to E. coli.

scholarly journals Seroprevalence of Antibodies against Pkn1, a Novel Potential Immunogen, inChlamydia trachomatis-InfectedMacaca nemestrinaand Human Patients

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Achchhe L. Patel ◽  
Prashant K. Mishra ◽  
Divya Sachdev ◽  
Uma Chaudhary ◽  
Dorothy L. Patton ◽  
...  
Keyword(s):  
Immune Responses ◽  
Genital Tract ◽  
Protein A ◽  
Macaca Nemestrina ◽  
Sexually Transmitted ◽  
Host Immune Responses ◽  
Bioinformatic Tools ◽  
Genital Tract Infections ◽  
Tract Infections

Chlamydia trachomatis(CT) is an important cause of sexually transmitted genital tract infections (STIs) and trachoma. Despite major research into chlamydial pathogenesis and host immune responses, immunoprotection has been hampered by the incomplete understanding of protective immunity in the genital tract. Characterized vaccine candidates have shown variable efficacy ranging from no protection to partial protectionin vivo. It is therefore a research priority to identify novel chlamydial antigens that may elicit protective immune responses against CT infection. In the present study we assessed the seroprevalence of antibodies against protein kinase1 (Pkn1), DNA ligaseA (LigA), and major outer membrane protein A (OmpA) following natural CT infection in humans and in experimentally induced CT infection inMacaca nemestrina. Antigenic stretches of Pkn1, LigA, and OmpA were identified using bioinformatic tools.Pkn1,LigA, andOmpAgenes were cloned in bacterial expression vector and purified by affinity chromatography. Our results demonstrate significantly high seroprevalence of antibodies against purified Pkn1 and OmpA in sera obtained from the macaque animal model and human patients infected with CT. In contrast no significant seroreactivity was observed for LigA. The seroprevalence of antibodies against Pkn1 suggest that nonsurface chlamydial proteins could also be important for developing vaccines forC. trachomatis.

scholarly journals Decoration of Outer Membrane Vesicles with Multiple Antigens by Using an Autotransporter Approach

2014 ◽  
Vol 80 (18) ◽  
pp. 5854-5865 ◽  
Author(s):  
Maria H. Daleke-Schermerhorn ◽  
Tristan Felix ◽  
Zora Soprova ◽  
Corinne M. ten Hagen-Jongman ◽  
David Vikström ◽  
...  
Keyword(s):  
Immune Responses ◽  
Outer Membrane ◽  
Vaccine Development ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Heterologous Proteins ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Heterologous Antigens

ABSTRACTOuter membrane vesicles (OMVs) are spherical nanoparticles that naturally shed from Gram-negative bacteria. They are rich in immunostimulatory proteins and lipopolysaccharide but do not replicate, which increases their safety profile and renders them attractive vaccine vectors. By packaging foreign polypeptides in OMVs, specific immune responses can be raised toward heterologous antigens in the context of an intrinsic adjuvant. Antigens exposed at the vesicle surface have been suggested to elicit protection superior to that from antigens concealed inside OMVs, but hitherto robust methods for targeting heterologous proteins to the OMV surface have been lacking. We have exploited our previously developed hemoglobin protease (Hbp) autotransporter platform for display of heterologous polypeptides at the OMV surface. One, two, or three of theMycobacterium tuberculosisantigens ESAT6, Ag85B, and Rv2660c were targeted to the surface ofEscherichia coliOMVs upon fusion to Hbp. Furthermore, a hypervesiculating ΔtolRΔtolAderivative of attenuatedSalmonella entericaserovar Typhimurium SL3261 was generated, enabling efficient release and purification of OMVs decorated with multiple heterologous antigens, exemplified by theM. tuberculosisantigens and epitopes fromChlamydia trachomatismajor outer membrane protein (MOMP). Also, we showed that delivery ofSalmonellaOMVs displaying Ag85B to antigen-presenting cellsin vitroresults in processing and presentation of an epitope that is functionally recognized by Ag85B-specific T cell hybridomas. In conclusion, the Hbp platform mediates efficient display of (multiple) heterologous antigens, individually or combined within one molecule, at the surface of OMVs. Detection of antigen-specific immune responses upon vesicle-mediated delivery demonstrated the potential of our system for vaccine development.

scholarly journals In Vivo mRNA Profiling of Uropathogenic Escherichia coli from Diverse Phylogroups Reveals Common and Group-Specific Gene Expression Profiles

mBio ◽  
2014 ◽  
Vol 5 (4) ◽  
Author(s):  
Piotr Bielecki ◽  
Uthayakumar Muthukumarasamy ◽  
Denitsa Eckweiler ◽  
Agata Bielecka ◽  
Sarah Pohl ◽  
...  
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Specific Gene ◽  
Content Type ◽  
E Coli ◽  
Human Host ◽  
Tract Infections

ABSTRACTmRNA profiling of pathogens during the course of human infections gives detailed information on the expression levels of relevant genes that drive pathogenicity and adaptation and at the same time allows for the delineation of phylogenetic relatedness of pathogens that cause specific diseases. In this study, we used mRNA sequencing to acquire information on the expression ofEscherichia colipathogenicity genes during urinary tract infections (UTI) in humans and to assign the UTI-associatedE. coliisolates to different phylogenetic groups. Whereas thein vivogene expression profiles of the majority of genes were conserved among 21E. colistrains in the urine of elderly patients suffering from an acute UTI, the specific gene expression profiles of the flexible genomes was diverse and reflected phylogenetic relationships. Furthermore, genes transcribedin vivorelative to laboratory media included well-described virulence factors, small regulatory RNAs, as well as genes not previously linked to bacterial virulence. Knowledge on relevant transcriptional responses that drive pathogenicity and adaptation of isolates to the human host might lead to the introduction of a virulence typing strategy into clinical microbiology, potentially facilitating management and prevention of the disease.IMPORTANCEUrinary tract infections (UTI) are very common; at least half of all women experience UTI, most of which are caused by pathogenicEscherichia colistrains. In this study, we applied massive parallel cDNA sequencing (RNA-seq) to provide unbiased, deep, and accurate insight into the nature and the dimension of the uropathogenicE. coligene expression profile during an acute UTI within the human host. This work was undertaken to identify key players in physiological adaptation processes and, hence, potential targets for new infection prevention and therapy interventions specifically aimed at sabotaging bacterial adaptation to the human host.

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