Aims:  To compare the bacteriostatic and bactericidal activity of 13 chemotyped essential oils (EO) on 65 bacteria with varying sensitivity to antibiotics. Methods and Results:  Fifty‐five bacterial strains were tested with two methods used for evaluation of antimicrobial activity (CLSI recommendations): the agar dilution method and the time‐killing curve method. EO containing aldehydes (Cinnamomum verum bark and Cymbopogon citratus), phenols (Origanum compactum, Trachyspermum ammi, Thymus satureioides, Eugenia caryophyllus and Cinnamomum verum leaf) showed the highest antimicrobial activity with minimum inhibitory concentration (MIC) <2% (v/v) against all strains except Pseudomonas aeruginosa. Alcohol‐based EO (Melaleuca alternifolia, Cymbopogon martinii and Lavandula angustifolia) exhibited varying degrees of activity depending on Gram status. EO containing 1·8‐cineole and hydrocarbons (Eucalyptus globulus, Melaleuca cajeputii and Citrus sinensis) had MIC90% ≥ 10% (v/v). Against P. aeruginosa, only C. verum bark and O. compactum presented MIC ≤2% (v/v). Cinnamomum verum bark, O. compactum, T. satureioides, C. verum leaf and M. alternifolia were bactericidal against Staphylococcus aureus and Escherichia coli at concentrations ranging from to 0·31% to 10% (v/v) after 1 h of contact. Cinnamomum verum bark and O. compactum were bactericidal against P. aeruginosa within 5 min at concentrations <2% (v/v). Conclusions:  Cinnamomum verum bark had the highest antimicrobial activity, particularly against resistant strains. Significance and Impact of the Study:  Bacteriostatic and bactericidal activity of EO on nosocomial antibiotic‐resistant strains.

IntroductionMost data on de-escalation of empirical antimicrobial therapy has focused on ventilator-associated pneumonia. In this retrospective monocentric study, we evaluated de-escalation as part of a global strategy of empiric antibiotherapy management irrespective of the location and the severity of the infection. The goal of this trial was to assess the application of a de-escalation strategy and the impact in terms of re-escalation, recurrent infection and to identify variables associated with de-escalation.MethodsAll consecutive patients treated with empiric antibiotic therapy and hospitalized in the intensive care unit for at least 72 hours within a period of 16 months were included. We compared the characteristics and outcome of patients who have experienced de-escalation therapy with those who have not.ResultsA total of 116 patients were studied corresponding to 133 infections. Antibiotic therapy was de-escalated in 60 cases (45%). De-escalation, primarily accomplished by a reduction in the number of antibiotics used, was observed in 52% of severe sepsis or septic shock patients. Adequate empiric antibiotic and use of aminoglycoside were independently linked with de-escalation. De-escalation therapy was associated with a significant reduction of recurrent infection (19% vs 5% P = 0.01). Mortality was not changed by de-escalation.ConclusionsAs part of a global management of empiric antibiotherapy in an intensive care unit, de-escalation might be safe and feasible in a large proportion of patients.

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These results emphasize the need for applying various infection control measures to prevent colonization of patients with P. aeruginosa, including strategies to limit the potential of sinks from acting as a source or reservoir for this bacterium.

The existence of a specific transport mechanism of penetration of nebulized particles delivered with acoustic airflow was proposed.