[Mold infections in lung transplants]

Bronchopulmonary penetration of isavuconazole in lung transplant recipients

Isavuconazole's (ISA) pharmacokinetics was studied among lung transplant recipients to evaluate its bronchopulmonary penetration. This study included 13 patients and showed mean serum concentrations of 3.30 (standard deviation [SD] 0.45), 5.12 (SD 1.36), and 6.31 (SD 0.95) at 2 h, 4 h, and 24 h respectively. Mean concentrations in the epithelial lining fluid were 0.969 (SD 0.895), 2.141 (SD 1.265), and 2.812 (SD 0.693) at the same time points. ISA is a drug with a tolerable safety profile that achieves adequate concentrations in the lung.

Phase IV clinical trial with a single treatment arm to evaluate bronchopulmonary penetration of isavuconazole in pulmonary transplant recipients (PBISA01): Study protocol clinical trial. (Preprint)

Background

Aspergillosis is the most frequently observed invasive fungal disease (IFD) in lung transplant recipients. Isavuconazole (ISA) has shown a better safety profile and noninferiority to voriconazole in the treatment of patients with IFD.

Objective

The aim of this study is to describe the bronchopulmonary pharmacokinetic profile of oral ISA by analyzing the degree of penetration in the epithelial lining fluid and alveolar macrophages in patients receiving lung transplantation with a diagnosis of IFD.

Methods

A total of 12 patients aged ≥18 years receiving a lung transplant with an IFD diagnosis and indication for ISA treatment and follow-up bronchoscopy will be included in the study. After 5 days of treatment with ISA and before the treatment is discontinued, the patients will be randomized (1:1:1:1) to perform the scheduled bronchoscopy at various times after the administration of ISA (2, 4, 8, and 12 hours). In total, 4 blood samples will be obtained per patient: at 72 hours after treatment initiation, on the day of the bronchoscopy, at the time of the bronchoalveolar lavage (simultaneously), and at 7 days after treatment initiation, to analyze tacrolimus and ISA plasma levels. ISA concentrations will be measured in plasma, epithelial lining fluid, and alveolar macrophages by a high-performance liquid chromatography/UV coupled to fluorescence method.

Results

Enrollment for the PBISA01 trial began in October 2020 and was completed in October 2021. All samples will be analyzed once recruitment is complete, and the results are expected to be published in October 2022.

Conclusions

There are no clinical studies that analyze the bronchopulmonary penetration of ISA. Bronchoalveolar lavage performed routinely in the follow-up of lung transplant recipients constitutes an opportunity to analyze the bronchopulmonary penetration of ISA.

Trial Registration

European Clinical Trials Register 2019-004240-30; www.clinicaltrialsregister.eu/ctr-search/trial/2019-004240-30/ES

International Registered Report Identifier (IRRID)

DERR1-10.2196/37275

Allicin reduces inflammation by regulating ROS/NLRP3 and autophagy in the context of A. fumigatus infection in mice

OBJECTIVES

Inhibitory effect of allicin with broad-spectrum antimicrobial activity on A. fumigatus and the regulation mechanism of inflammation and autophagy in vitro and in vivo.

METHODS

The corresponding concentration of allicin was prepared according to the needs of the experiment. In vitro, 2 ml 5 × 10⁴ of fungal spores suspension was added to the 6-well plate per hole, and different final concentrations of allicin (1 μl/ml, 2.5 μl/ml, 5 μl/ml, 10 μl/ml, 20 μl/ml, 30 μl/ml) were added. The fungal spores were stained by fluorescent dye SYTO 9 (green) every day, and the spore germination inhibition was detected by flow cytometry in different PH. RAW264.7 cells were cultured and stimulated by A. fumigatus spores for 3 h, then allicin solution was added. Then some cells were stained with ROS probe (green) and hochest33342 (blue). The effect of allicin on ROS was observed by fluorescence microscope. The other part of cells extracted protein from cell lysate and detected the effect of allicin on inflammatory factors and autophagy by Western-blotting. The green and red spots of RAW264.7 cells stably transfected with GFP-RFP-LC3 were observed by fluorescence microscopy. In vivo, A. fumigatus spore was injected intratracheally into mice, then allicin was injected intravenously at a concentration of 5 mg/kg/day for 7 consecutive days. The survival status, pulmonary fungal load and weight of mice was recorded continuously for 30 days and detected the changes of lung by pathological examination and immunohistochemistry.

RESULTS

In vitro, allicin significantly inhibited the spore germination of A. fumigatus within 24 h in a dose-dependent manner and it had a stable inhibition on the spore germination of A. fumigatus in acidic environment. Cell experiments showed that allicin inhibited intracellular spore germination by inhibiting ROS production, inflammation and autophagy. In the animal experiment, the survival rate and body weight of allicin injection group were higher than that of non injection group, while the spore load of lung was lower than that of non injection group (P < 0.05).

CONCLUSIONS

These results support that allicin reduces inflammation and autophagy resistance to A. fumigatus infection, It also provides a possible treatment for Aspergillus infectious diseases, i.e. early anti-inflammation, antibiotics or drugs that inhibit excessive autophagy.

Bloodstream Infections

Bacteremia and sepsis are conditions associated with high mortality and are of great impact to health care operations. Among the top causes of mortality in the United States, these conditions cause over 600 fatalities each day. Empiric, broad-spectrum treatment is a common but often a costly approach that may fail to effectively target the correct microbe, may inadvertently harm patients via antimicrobial toxicity or downstream antimicrobial resistance. To meet the diagnostic challenges of bacteremia and sepsis, laboratories must understand the complexity of diagnosing and treating septic patients, in order to focus on creating algorithms that can help direct a more targeted approach to antimicrobial therapy and synergize with existing clinical practices defined in new Surviving Sepsis Guidelines. Significant advances have been made in improving blood culture media; as yet no molecular or antigen-based method has proven superior for the detection of bacteremia in terms of limit of detection. Several methods for rapid molecular identification of pathogens from blood cultures bottles are available and many more are on the diagnostic horizon. Ultimately, early intervention by molecular detection of bacteria and fungi directly from whole blood could provide the most patient benefit and contribute to tailored antibiotic coverage of the patient early on in the course of the disease. Although blood cultures remain as the best means of diagnosing bacteremia and candidemia, complementary testing with antigen tests, microbiologic investigations from other body sites, and histopathology can often aid in the diagnosis of disseminated disease, and application of emerging nucleic acid test methods and other new technology may greatly impact our ability to bacteremic and septic patients, particularly those who are immunocompromised.