Adjunctive inhaled amikacin in infants with Ventilator-Associated Pneumonia optimizes the complex antimicrobial therapy: pilot study

Abstract

Background and aim: VAP remains the second leading cause of death among the patients with nosocomial infections and its incidence varies significantly from 5% to 60% reaching on average 10 %. It is of crucial importance to develop novel treatment approaches and optimize the existing ones. Thus, the aim of this pilot study was to study the laboratory-microbiological effect of inhaled aminoglycosides in a complex treatment of patients with ventilator-associatedpneumonia(VAP). Methods: To study the laboratory-microbiological effect of adjunctive inhaled aminoglycosides in the treatment of VAP, twenty enrolled patients were randomly subdivided into 2 groups (n=10). Amikacin was administered via a nebulizer starting from the first day of VAP manifestation. Inhalations were performed BID for 7 days via a nebulizer integrated into the breathing circuit. We assessed: cell membrane alterations in leukocytes, Annexin V/7-AAD staining for leukocytes, ROS detection assay for leukocytes.

Results: Adjunctive administration of inhaled amikacin reduced the fluorescence intensity ratio more efficiently compared with the intravenous antimicrobial treatment with no aerosolized amikacin following both 48 h and 96 h of treatment. The amount of dead necrotic annexin V-negative, 7-AAD-positive leukocytes was significantly lower under the use of inhaled amikacin than at the beginning of treatment. Conclusions In this pilot study, we found that administration of aerosolized amikacin combined with the systemic antimicrobial therapy improves the clinical outcome of patients with VAP, effective early microbial decrease in the sputum, reduces reactive oxygen species generation in leukocytes and the degree of leukocyte apoptosis and necrosis, decreases VAP-mediated cell membrane alterations of circulating leukocytes.

Figure 1.

Flow-chart of patient selection.

Figure 2.

Localization and orientation of fluorescent probe O1O in the outer leaflet of the phospholipid membranes.

Figure 3.

The subsequent double gating to identify the subpopulations of CD45-positive cells (left panel) and viable 7-aminoactinomycin D-negative CD45-positive cells (right panel).

Figure 4.

Representative fluorescence spectra of probe O1O in leukocyte suspensions of patients with ventilator-associated pneumonia at the beginning (panel a), after 48 h (panel b), and 96 h (panel c) of treatment duration: conventional systemic antimicrobial treatment (blue solid line) and systemic antibacterial treatment in combination with nebulized amikacin (red dashed line).

Figure 5.

Representative histograms of dichlorofluorescein fluorescence in viable leukocytes obtained from the patients with ventilator-associated pneumonia treated with conventional systemic antibiotics and systemic antibacterial agents in combination with adjunctive inhaled amikacin. The samples were prepared from blood collected directly prior the beginning of treatment (panel a), after 48 h (panel b) and 96 h (panel c).

Figure 6.

Representative annexin V / 7-aminoactinomycin D dotplots of CD45-expressing cells obtained from the blood of patients with ventilator-associated pneumonia following 48 h with conventional systemic antibiotics (panel a) and systemic antibacterial agents + adjunctive inhaled amikacin (panel b).