Display omitted
Antibiotic therapy has become increasingly ineffective against bacterial infections due to the rise of resistance. In particular, ESKAPE pathogens (Enterococcus faecium, ...Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) have caused life-threatening infections in humans and represent a major global health threat due to a high degree of antibiotic resistance. To respond to this urgent call, novel strategies are urgently needed, such as bacteriophages (or phages), phage-encoded enzymes, immunomodulators and monoclonal antibodies. This review critically analyses these promising antimicrobial therapies for the treatment of multidrug-resistant bacterial infections. Recent advances in these novel therapeutic strategies are discussed, focusing on preclinical and clinical investigations, as well as combinatorial approaches. In this ‘Bad Bugs, No Drugs’ era, novel therapeutic strategies can play a key role in treating deadly infections and help extend the lifetime of antibiotics.
Wound infections associated with multidrug-resistant (MDR) bacteria are one of the important threats to public health. Bacteriophage (phage) therapy is a promising alternative or supplementary ...therapeutic approach to conventional antibiotics for combating MDR bacterial infections. In recent years, significant effort has been put into the development of phage formulations and delivery methods for topical applications, along with preclinical and clinical uses of phages for the treatment of acute and chronic wound infections. This paper reviews the application of phages for wound infections, with focus on the current status of phage formulations (including liquid, semi-solid and liposome-encapsulated formulations, phage-immobilized wound dressings), safety and efficacy assessment in clinical settings and major challenges to overcome.
Display omitted
Bacteriophage (phage) therapy is a promising treatment strategy to combat antibiotic-resistant bacteria. Clinical reports from a century ago, as well as recent reports have revealed ...safety and efficacy of phage therapy for bacterial wound infections. However, the conventional liquid phage formulation and delivery platforms reported lack of dose control as it easily runs off from the infection site and it is impossible to determine total volume transfer. The aim of this study was to formulate phage liquids for topical delivery using a metered-dose spray. Two types of anti-Pseudomonas phages, PEV1 (myovirus) and PEV31 (podovirus) were formulated in 35% ethanol in water containing non-ionic polymers. The formulations were evaluated for physical properties, ease of spray, dripping upon spraying, drying time, in vitro release profiles, antibacterial activity, and storage stability. The optimized phage-polymer spray formulations were easily sprayable with minimal dripping and fast drying time. Phages were rapidly released from the formulation and inhibited the growth of Pseudomonas aeruginosa. Both PEV1 and PEV31 remained biologically stable in the optimized formulations during storage at 4 °C for eight weeks. This study showed the topical spray formulations containing non-ionic polymers in ethanol/water could be a promising and innovative therapeutic system for delivering phages.
Display omitted
Novel inhalable and synergistic combination powder formulations of phage PEV20 and ciprofloxacin were recently developed to treat Pseudomonas aeruginosa respiratory infections. In the ...present study, we investigated the storage stability of these powders which comprised ciprofloxacin, lactose and L-leucine in mass ratios of 1:1:1 (Formulation A) or ciprofloxacin and L-leucine in 2:1 without lactose (Formulation B). These powders were produced by spray drying, collected in polypropylene tubes and packed inside aluminium pouches which were heat-sealed at < 20% relative humidity (RH), then stored at 4 °C or 25 °C. The phage viability, aerosol performance and solid-state properties of the powders were examined over 12 months. The biological activity and aerosol performance of both formulations showed no significant change over 12 months of storage at 4 °C. However, after four months of storage at 25 °C, a significant titer loss of 2.2 log10 (p < 0.01) was observed in Formulation B, but the loss in Formulation A was much less (0.5 log10 (p < 0.05)). In contrast, the fine particle fraction (FPF, wt. % particles ≤ 5 µm) of Formulation A was significantly reduced by 11% (p < 0.05) after four months of storage at 25 °C, whereas the aerosol performance of Formulation B remained stable over 12 months. The results showed that ciprofloxacin can sufficiently stabilize phage through vitrification and/or hydrogen bonding at 4 °C. The presence of lactose was beneficial to preserve the phage at 25 °C. In conclusion, spray dried PEV20-ciprofloxacin combination powders were biologically and physico-chemically stable even without lactose as a stabilising excipient, when stored below 20% RH at 4 °C for 12 months.
Display omitted
In vitro-in vivo correlation is the establishment of a predictive relationship between in vitro and in vivo data. In the context of cascade impactor results of orally inhaled ...pharmaceutical aerosols, this involves the linking of parameters such as the emitted dose, fine particle dose, fine particle fraction, and mass median aerodynamic diameter to in vivo lung deposition from scintigraphy data. If the dissolution and absorption processes after deposition are adequately understood, the correlation may be extended to the pharmacokinetics and pharmacodynamics of the delivered drugs. Correlation of impactor data to lung deposition is a relatively new research area that has been gaining recent interest. Although few in number, experiments and meta-analyses have been conducted to examine such correlations. An artificial neural network approach has also been employed to analyse the complex relationships between multiple factors and responses. However, much research is needed to generate more data to obtain robust correlations. These predictive models will be useful in improving the efficiency in product development by reducing the need of expensive and lengthy clinical trials.
Tuberculosis (TB) is an intracellular infectious disease caused by the airborne bacterium, Mycobacterium tuberculosis. Despite considerable research efforts, the treatment of TB continues to be a ...great challenge in part due to the requirement of prolonged therapy with multiple high-dose drugs and associated side effects. The delivery of pharmacological agents directly to the respiratory system, following the natural route of infection, represents a logical therapeutic approach for treatment or vaccination against TB. Pulmonary delivery is non-invasive, avoids first-pass metabolism in the liver and enables targeting of therapeutic agents to the infection site. Inhaled delivery also potentially reduces the dose requirement and the accompanying side effects. Dry powder is a stable formulation of drug that can be stored without refrigeration compared to liquids and suspensions. The dry powder inhalers are easy to use and suitable for high-dose formulations. This review focuses on the current innovations of inhalable dry powder formulations of drug and vaccine delivery for TB, including the powder production method, preclinical and clinical evaluations of inhaled dry powder over the last decade. Finally, the risks associated with pulmonary therapy are addressed. A novel dry powder formulation with high percentages of respirable particles coupled with a cost effective inhaler device is an appealing platform for TB drug delivery.
Display omitted
Cough is an adverse effect that may hinder the delivery of drugs into the lungs. Chemical or mechanical stimulants activate the transient receptor potential in some airway afferent nerves (C‐fibres ...or A‐fibres) to trigger cough. Types of inhaler device and drug, dose, excipients and formulation characteristics, including pH, tonicity, aerosol output and particle size may trigger cough by stimulating the cough receptors. Release of inflammatory mediators may increase the sensitivity of the cough receptors to stimulants. The cough‐provoking effect of aerosols is enhanced by bronchoconstriction in diseased airways and reduces drug deposition in the target pulmonary regions. In this article, we review the factors by which inhalation products may cause cough.
Antibiotic resistance remains as an unresolved global challenge in the health care system, posing serious threats to global health. As an alternative to antibiotics, bacteriophage (phage) therapy is ...rising as a key to combating antibiotic-resistant bacterial infections. In order to deliver a phage to the site of infection, hydrogels have been formulated to incorporate phages, owing to its favorable characteristics in delivering biological molecules. This paper reviews the formulation of phage-delivering hydrogels for orthopedic implant-associated bone infection, catheter-associated urinary tract infection and trauma-associated wound infection, with a focus on the preparation methods, stability, efficacy and safety of hydrogels as phage carriers.
Display omitted
Nebulization is currently used for delivery of antibiotics for respiratory infections. Bacteriophages (or phages) are effective predators of pathogens including Pseudomonas aeruginosa ...commonly found in the lungs of patients with cystic fibrosis (CF). It is known that phages and antibiotics can potentially show synergistic antimicrobial effect on bacterial killing. In the present study, we investigated synergistic antimicrobial effect of phage PEV20 with five different antibiotics against three P. aeruginosa strains isolated from sputum of CF patients. The antibiotics included ciprofloxacin, tobramycin, colistin, aztreonam and amikacin, which are approved by U.S Food and Drug Administration (FDA) for inhaled administration. Phage and antibiotic synergy was determined by assessing bacterial killing performing time-kill studies. Among the different phage-antibiotic combinations, PEV20 and ciprofloxacin exhibited the most synergistic effect. Two phage-ciprofloxacin combinations, containing 1/4 and 1/2 of the minimum inhibitory concentration (MIC) of ciprofloxacin against P. aeruginosa strains FADD1-PA001 (A) and JIP865, respectively were aerosolized using both air-jet and vibrating mesh nebulizers and the synergistic antibacterial activity was maintained after nebulization. Air-jet nebulizer generated droplets with smaller volume median diameters (3.6–3.7 µm) and slightly larger span (2.3–2.4) than vibrating mesh nebulizers (5.1–5.3 µm; 2.1–2.2), achieving a higher fine particle fraction (FPF) of 70%. In conclusion, nebulized phage PEV20 and ciprofloxacin combination shows promising antimicrobial and aerosol characteristics for potential treatment of respiratory tract infections caused by drug-resistant P. aeruginosa.
PDF
