Lower respiratory tract infections: etiology, current treatment, and experience with fluoroquinolones

Development and Characterization of Spray-Dried Combined Levofloxacin-Ambroxol Dry Powder Inhaler Formulation

Background: This study explores the development and characterization of spray-dried composite microparticles consisting of levofloxacin (LVX, a broad-spectrum antibiotic), and ambroxol (AMB, a mucolytic agent that has antibacterial and antibiofilm properties), for the intended application of the drug against lower respiratory tract infections (LRTIs). Methods: A range of LVX to AMB mass ratios (1:1, 1:0.5, and 1:0.25) were prepared, with and without the use of the dispersibility enhancer leucine (LEU), and spray-dried following pre-optimized parameters to achieve the required particle size (1-5 µm) and flow properties. The formulations were characterized by attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), and a thermogravimetric analysis (TGA). The in vitro aerosolization performance of the new formulation was evaluated with a twin-stage impinger (TSI) at a flow rate of 60 ± 5 L/min. Using a validated RP-HPLC method, LVX and AMB were quantitatively determined. Results: The combined spray-dried LVX, AMB, and LEU particles were spherically shaped with sizes ranging from 1.9 to 2.9 µm, thus complying with the size requirements for effective deep lung deposition. The dispersibility enhancer leucine produced a high yield and enhanced the flow properties and aerosolization characteristics of the spray-dried formulations. The LVX to AMB mass ratios showed a remarkable impact on the aerosolization properties, with the LVX to AMB 1:1 mass ratio demonstrating the best flow and FPFs for both drugs. There must be a balanced ratio of these components for spray drying the composite particles to obtain composite particles of the required size and with the appropriate flow property. The addition of 5% of LEU significantly (p < 0.005) improved the FPF of all the formulations, probably by enhancing the surface hydrophobicity of the composite particles. Conclusions: The spray-dried combined antibiotics formulation has a strong potential for efficient lung delivery intended for the management of LRTIs.

A four-part guide to lung immunology: Invasion, inflammation, immunity, and intervention

Lungs are important respiratory organs primarily involved in gas exchange. Lungs interact directly with the environment and their primary function is affected by several inflammatory responses caused by allergens, inflammatory mediators, and pathogens, eventually leading to disease. The immune architecture of the lung consists of an extensive network of innate immune cells, which induce adaptive immune responses based on the nature of the pathogen(s). The balance of immune responses is critical for maintaining immune homeostasis in the lung. Infection by pathogens and physical or genetic dysregulation of immune homeostasis result in inflammatory diseases. These responses culminate in the production of a plethora of cytokines such as TSLP, IL-9, IL-25, and IL-33, which have been implicated in the pathogenesis of several inflammatory and autoimmune diseases. Shifting the balance of Th1, Th2, Th9, and Th17 responses have been the targets of therapeutic interventions in the treatment of these diseases. Here, we have briefly reviewed the innate and adaptive i3mmune responses in the lung. Genetic and environmental factors, and infection are the major causes of dysregulation of various functions of the lung. We have elaborated on the impact of inflammatory and infectious diseases, advances in therapies, and drug delivery devices on this critical organ. Finally, we have provided a comprehensive compilation of different inflammatory and infectious diseases of the lungs and commented on the pros and cons of different inhalation devices for the management of lung diseases. The review is intended to provide a summary of the immunology of the lung, with an emphasis on drug and device development.

Opportunities for Improving Antimicrobial Stewardship: Findings From a Prospective, Multi-Center Study in Three Low- or Middle-Income Countries

Background

To develop effective antimicrobial stewardship programs (ASPs) for low- and middle-income countries (LMICs), it is important to identify key targets for improving antimicrobial use. We sought to systematically describe the prevalence and patterns of antimicrobial use in three LMIC hospitals.

Methods

Consecutive patients admitted to the adult medical wards in three tertiary care hospitals in Tanzania, Kenya, and Sri Lanka were enrolled in 2018-2019. The medical record was reviewed for clinical information including type and duration of antimicrobials prescribed, indications for antimicrobial use, and microbiologic testing ordered.

Results

A total of 3,149 patients were enrolled during the study period: 1,103 from Tanzania, 750 from Kenya, and 1,296 from Sri Lanka. The majority of patients were male (1,783, 56.6% overall) with a median age of 55 years (IQR 38-68). Of enrolled patients, 1,573 (50.0%) received antimicrobials during their hospital stay: 35.4% in Tanzania, 56.5% in Kenya, and 58.6% in Sri Lanka. At each site, the most common indication for antimicrobial use was lower respiratory tract infection (LRTI; 40.2%). However, 61.0% received antimicrobials for LRTI in the absence of LRTI signs on chest radiography. Among patients receiving antimicrobials, tools to guide antimicrobial use were under-utilized: microbiologic cultures in 12.0% and microbiology consultation in 6.5%.

Conclusion

Antimicrobials were used in a substantial proportion of patients at tertiary care hospitals across three LMIC sites. Future ASP efforts should include improving LRTI diagnosis and treatment, developing antibiograms to direct empiric antimicrobial use, and increasing use of microbiologic tests.

The spectrum of Cefditoren for Lower Respiratory Tract Infections (LRTIs) in Surabaya

Background:

Empirical antibiotics among outpatients with Lower Respiratory Tract Infections (LRTIs) are scarcely allocated in Indonesia. The study aims to evaluate the pathogens causing LRTIs, drug sensitivity test and the minimum inhibitory concentrations of 90% (MIC90) of Cefditoren, Azithromycin, Amoxicillin-Clavulanic Acid, and Cefixime

Methods:

The study was performed in adult outpatients with LRTI that can be expectorated. Patients with diabetes mellitus, HIV, lung tuberculosis, renal or hepatic failure, and hemoptysis were excluded. We performed bacterial culture, antibiotic sensitivity, and MIC measurement of four antibiotics.

Results:

There were 126 patients with LRTIs, and 61 patients were eligible for the study. We identified 69 bacteria. We found Klebsiella pneumonia (n=16; 26.23%), Staphylococcus aureus (n=11; 18%), Pseudomonas aeruginosa (n=8; 13.11%), Acinetobacter baumanii complex (n= 4; 6.55%), Streptococcus pneumonia (n=3; 4.9%) and others bacteria as causa of LRTI. Testing MIC90 of Cefditoren and three empiric antibiotics on LRTI found that Cefditoren has a lower MIC of 90 for K. pneumonia (0.97(2.04) µg.mL-1) and S. pneumonia (0.06(0.00)µg.mL-1) than other antibiotics, but almost the same as Cefixime ((0.05(0.16)µg.mL-1) and (0.38(0.17)µg.mL-1). MIC90 Cefditoren for S.aureus (3.18(3.54)µg.mL-1) and P.aeruginosa (9.2(3.53)µg.mL-1) is lower than Cefixime but higher than Azithromycin and Amoxicillin-Clavulanic acid. Reference data MIC90 of Cefditoren for LRTI bacteria is lower than the other three oral empirical antibiotics.

Conclusions:

In vitro studies of an outpatient LRTI in Surabaya found gram-negative bacteria dominant. Cefditoren can inhibit K.pneumonia and S.pneumonia has lower MIC90 compared to other antibiotics. Cefditoren can inhibit gram-negative and positive bacteria causing LRTI.