Vaccines for preventing infection with Pseudomonas aeruginosa in cystic fibrosis

The protective effects of nasal PcrV-CpG oligonucleotide vaccination against Pseudomonas aeruginosa pneumonia

An effective vaccine against Pseudomonas aeruginosa would be hugely beneficial to people who are susceptible to the serious infections it can cause. Vaccination against PcrV of the P. aeruginosa type III secretion system is a potential prophylactic strategy for improving the incidence and prognosis of P. aeruginosa pneumonia. Here, the effect of nasal PcrV adjuvanted with CpG oligodeoxynucleotide (CpG) was compared with a nasal PcrV/aluminum hydroxide gel (alum) vaccine. Seven groups of mice were vaccinated intranasally with one of the following: 1, PcrV-CpG; 2, PcrV-alum; 3, PcrV alone; 4, CpG alone; 5, alum alone; 6 and 7, saline control. Fifty days after the first immunization, anti-PcrV IgG, IgA and IgG isotype titers were measured; significant increases in these titers were detected only in the PcrV-CpG vaccinated mice. The vaccinated mice were then intratracheally infected with a lethal dose of P. aeruginosa and their body temperatures and survival monitored for 24 hr, edema, bacteria, myeloperoxidase activity and lung histology also being evaluated at 24 hr post-infection. It was found that 73% of the PcrV-CpG-vaccinated mice survived, whereas fewer than 30% of the mice vaccinated with PcrV-alum or adjuvant alone survived. Lung edema and other inflammation-related variables were less severe in the PcrV-CpG group. The significant increase in PcrV-specific IgA titers detected following PcrV-CpG vaccination is probably a component of the disease protection mechanism. Overall, our data show that intranasal PcrV-CpG vaccination has potential efficacy for clinical application against P. aeruginosa pneumonia.

[Chronic Pseudomonas aeruginosa airway colonization in cystic fibrosis patients : Prevention concepts]

Pseudomonas aeruginosa (PsA) is a hallmark pathogen of the lung disease in cystic fibrosis (CF) patients. Chronic PsA colonization is a central factor in the course of CF lung disease. PsA contributes considerably to morbidity and mortality, and also has a significant impact on quality of life and the costs of CF treatment. Prevention of chronic colonization has therefore been a major goal in the treatment of CF patients for many years now. In the present article, studies are presented which suggest that prevention of chronic colonization can be achieved. Approaches to prevent chronic PsA colonization are critically evaluated and recommendations for preventative approaches are generated from this discussion.

Draft Genome Sequence of a Pseudomonas aeruginosa Strain Able To Decompose N , N -Dimethyl Formamide

Pseudomonas aeruginosa is a Gram-negative bacterium, which uses a variety of organic chemicals as carbon sources. Here, we report the genome sequence of the Cu1510 isolate from wastewater containing a high concentration of N,N-dimethyl formamide.

Vaccines for preventing infection with Pseudomonas aeruginosa in cystic fibrosis

BACKGROUND

Chronic pulmonary infection in cystic fibrosis results in progressive lung damage. Once colonisation of the lungs with Pseudomonas aeruginosa occurs, it is almost impossible to eradicate. Vaccines, aimed at reducing infection with Pseudomonas aeruginosa, have been developed. This is an update of a previously published review.

OBJECTIVES

To assess the effectiveness of vaccination against Pseudomonas aeruginosa in cystic fibrosis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register using the terms vaccines AND pseudomonas (last search 30 March 2015). We previously searched PubMed using the terms vaccin* AND cystic fibrosis (last search 30 May 2013).

SELECTION CRITERIA

Randomised trials (published or unpublished) comparing Pseudomonas aeruginosa vaccines (oral, parenteral or intranasal) with control vaccines or no intervention in cystic fibrosis.

DATA COLLECTION AND ANALYSIS

The authors independently selected trials, assessed them and extracted data.

MAIN RESULTS

Six trials were identified. Two trials were excluded since they were not randomised and one old, small trial because it was not possible to assess whether is was randomised. The three included trials comprised 483, 476 and 37 patients, respectively. No data have been published from one of the large trials, but the company stated in a press release that the trial failed to confirm the results from an earlier study and that further clinical development was suspended. In the other large trial, relative risk for chronic infection was 0.91 (95% confidence interval 0.55 to 1.49), and in the small trial, the risk was also close to one. In the large trial, one patient was reported to have died in the observation period. In that trial, 227 adverse events (4 severe) were registered in the vaccine group and 91 (1 severe) in the control group. In this large trial of a vaccine developed against flagella antigens, antibody titres against the epitopes contained in the vaccine were higher in the vaccine group compared to the placebo group (P < 0.0001).

AUTHORS' CONCLUSIONS

Vaccines against Pseudomonas aeruginosa cannot be recommended.

Vaccines for preventing infection with Pseudomonas aeruginosa in cystic fibrosis

BACKGROUND

Chronic pulmonary infection in cystic fibrosis results in progressive lung damage. Once colonisation of the lungs with Pseudomonas aeruginosa occurs, it is almost impossible to eradicate. Vaccines, aimed at reducing infection with Pseudomonas aeruginosa, have been developed.

OBJECTIVES

To assess the effectiveness of vaccination against Pseudomonas aeruginosa in cystic fibrosis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register using the terms vaccines AND pseudomonas (last search 30 May 2013) and PubMed using the terms vaccin* AND cystic fibrosis (last search 30 May 2013).

SELECTION CRITERIA

Randomised trials (published or unpublished) comparing Pseudomonas aeruginosa vaccines (oral, parenteral or intranasal) with control vaccines or no intervention in cystic fibrosis.

DATA COLLECTION AND ANALYSIS

The authors independently selected trials, assessed them and extracted data.

MAIN RESULTS

Six trials were identified. Two trials were excluded since they were not randomised and one old, small trial because it was not possible to assess whether is was randomised. The three included trials comprised 483, 476 and 37 patients, respectively. No data have been published from one of the large trials, but the company stated in a press release that the trial failed to confirm the results from an earlier study and that further clinical development was suspended. In the other large trial, relative risk for chronic infection was 0.91 (95% confidence interval 0.55 to 1.49), and in the small trial, the risk was also close to one. In the large trial, one patient was reported to have died in the observation period. In that trial, 227 adverse events (4 severe) were registered in the vaccine group and 91 (1 severe) in the control group. There was a marked rise in flagella antibody titres in the vaccine group and no change in the placebo group (P < 0.0001).

AUTHORS' CONCLUSIONS

Vaccines against Pseudomonas aeruginosa cannot be recommended.

Interleukin-22 produced by alveolar macrophages during activation of the innate immune response

OBJECTIVE AND DESIGN

Interleukin (IL)-22 is important for mucosal host defense. Whereas previous studies focus on lymphocytes as sources of IL-22, we determined whether IL-22 is produced by inflammatory cells in the lungs other than T-lymphocytes during the activation of the innate immune response.

MATERIAL, METHODS AND TREATMENT

Inflammatory cells in the lungs of Balb/c mice were primed by endotoxin (LPS, 10 μg) or peptidoglycan (PG, 40 μg) intranasally (3 days). After CD3 + cell depletion, lung homogenates were re-stimulated 24 h with LPS (100 ng/ml), PG (10 μg/ml), IL-23 (100 ng/ml) or vehicle. Human BAL macrophages were stimulated 24 h with PG (50 μg/ml) and IL-23 (100 ng/ml) or vehicle. The release of IL-22 was measured with ELISA and intracellular IL-22 with immunostaining. For statistics, either Dunnett or Students t test method was employed (n = 3-8).

RESULTS

Re-stimulation in vitro increased concentrations of mouse IL-22 protein irrespective of priming in vivo. A majority of macrophages in mouse lung and BAL samples displayed immunostaining for IL-22. In analogy, human BAL macrophages released IL-22 protein, and a third of these cells displayed immunostaining for IL-22.

CONCLUSIONS

Alveolar macrophages can produce and release IL-22 during the activation of the innate immune response and thereby constitute a potentially important regulator of mucosal host defence in the lungs.

A genetic approach to the development of new therapeutic phages to fight pseudomonas aeruginosa in wound infections

Pseudomonas aeruginosa is a frequent participant in wound infections. Emergence of multiple antibiotic resistant strains has created significant problems in the treatment of infected wounds. Phage therapy (PT) has been proposed as a possible alternative approach. Infected wounds are the perfect place for PT applications, since the basic condition for PT is ensured; namely, the direct contact of bacteria and their viruses. Plenty of virulent ("lytic") and temperate ("lysogenic") bacteriophages are known in P. aeruginosa. However, the number of virulent phage species acceptable for PT and their mutability are limited. Besides, there are different deviations in the behavior of virulent (and temperate) phages from their expected canonical models of development. We consider some examples of non-canonical phage-bacterium interactions and the possibility of their use in PT. In addition, some optimal approaches to the development of phage therapy will be discussed from the point of view of a biologist, considering the danger of phage-assisted horizontal gene transfer (HGT), and from the point of view of a surgeon who has accepted the Hippocrates Oath to cure patients by all possible means. It is also time now to discuss the possible approaches in international cooperation for the development of PT. We think it would be advantageous to make phage therapy a kind of personalized medicine.

Novel approaches to the treatment of Pseudomonas aeruginosa infections in cystic fibrosis

Pseudomonas aeruginosa chronically infects patients with cystic fibrosis and is associated with greater morbidity. There has been limited progress on the clinical development of new antibiotics with novel modes of action. This review addresses some of the latest research developments on the exploitation of candidate adjuvant therapeutic agents that may act alongside conventional antibiotics as an alternative therapeutic strategy. After considering key mechanisms this opportunistic pathogen employs to control virulence, the progress of various strategies including the inhibition of quorum sensing, efflux pumps and lectins, and the use of iron chelators, bacteriophages, immunisation and immunotherapy is reviewed. Both therapeutic approaches in early development and clinical phase are discussed.

Management of refractory Pseudomonas aeruginosa infection in cystic fibrosis

Cystic fibrosis (CF) is the most common life-limiting inherited disease in Caucasian populations. The main cause of death in CF patients is respiratory failure resulting from chronic pulmonary infection. Pseudomonas aeruginosa is the most prevalent organism in the airway colonization of CF patients, and its persistence in the airways has been related to greater morbidity with a more rapid deterioration in lung function. P. aeruginosa has enormous genetic and metabolic flexibility that allows it to adapt and persist within the airways of CF patients, and it has the ability to easily acquire antimicrobial resistance. For these reasons, the management of infections and chronic colonization by P. aeruginosa remains a challenge for physicians. This article reviews the current and future antibacterial chemotherapy options for respiratory pseudomonal infection in CF patients.

Early eradication of Pseudomonas aeruginosa in patients with cystic fibrosis

Pseudomonas aeruginosa (Pa) is the predominant organism infecting the airways of patients with cystic fibrosis (CF). This organism has an armamentarium of survival mechanisms that allows it to survive in the CF airway. Since colonization and chronic infection with Pa is associated with poorer lung function and increased morbidity and mortality, therapies that can prevent infection could significantly improve the lives of patients with CF. Numerous studies have examined the effects of treatment on the eradication of Pa as a means to ameliorate disease. This article outlines the pathophysiology and clinical implication of Pa acquisition, and reviews the existing treatment regimens aimed at early eradication of Pa in patients with CF.

Emerging treatments in cystic fibrosis

There are a number of potential drugs for the treatment of cystic fibrosis (CF) currently undergoing clinical studies. A number of antibacterials formulated for delivery by inhalation are at various stages of study; these include dry-powder inhaler versions of colistin, tobramycin and ciprofloxacin, and formulations of azteonam, amikacin, levofloxacin, ciprofloxacin and fosfomycin/tobramycin for nebulization. Clinical trials of anti-inflammatory agents, including glutathione, phosphodiesterase-5 inhibitors such as sildenafil, oral acetylcysteine, simvastatin, methotrexate, docosahexaenoic acid, hydroxychloroquine, pioglitazone and alpha1-antitrypsin, are ongoing. Ion channel modulating agents, such as lancovutide (Moli1901, duramycin) and denufosol, which activate alternate (non-CF transmembrane regulator [CFTR]) chloride channels, and GS 9411, a sodium channel antagonist, are now at the stages of clinical study and if successful, will offer a new category of therapeutic agent for the treatment of CF. Correction of the underlying gene effect, either by agents that help to correct the dysfunctional CFTR, such as ataluren, VX-770 and VX-809, or by gene transfer (gene therapy), is a particularly exciting prospect as a new therapy for CF and clinical studies are ongoing. This article reviews the exciting potential drug treatments for CF currently being evaluated in clinical studies, and also highlights some of the challenges faced by research and clinical teams in assessing the efficacy of potential new therapies for CF.