The authors concluded that inhaled antimicrobial monotherapy for pneumonia might be an option in certain cases, when systemic access is unavailable, or denied by the patient, or cannot be used due to systemic toxicity or limited bioavailability in the lungs. The lack of study quality assessment and limitations in the review process suggest that these conclusions may not be reliable.

To assess the effectiveness of antibiotic administration via the respiratory tract as monotherapy for pneumonia.

The databases of PubMed and Scopus were searched up to August 2007. Search terms were reported. Reference lists of retrieved publications were also screened.

Studies that evaluated one or more antimicrobials, delivered via the respiratory tract as monotherapy, in patients with pneumonia for at least two days, were eligible for inclusion. Studies which used concurrent inhaled and systemic antimicrobial administration were excluded, except when systemic antimicrobials were not active against the respiratory pathogens.

Colistin was the most frequently assessed antimicrobial administered via the respiratory tract in the included studies. Treatment duration of included studies ranged from two to 36 days. Acinetobacter baumannii, Pseudomonas aeruginosa and Gram-positive cocci were the most commonly isolated pathogens. The majority of included patients had community-acquired pneumonia, or nosocomial pneumonia, including ventilator-associated pneumonia. One-third of included patients received concurrent systemic antimicrobial therapy. The outcomes reported in the review were clinical cure, bacteriological eradication, all-cause mortality, and adverse events.

The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.

The authors did not state that the study validity was assessed.

It appeared that the authors extracted data on the measures for clinical cure, bacteriological eradication, all-cause mortality and adverse events.

The authors did not state how the data were extracted for the review, or how many reviewers performed the data extraction.

The studies were combined in a narrative synthesis, supported by accompanying data tables.

Seven studies (one randomised controlled trial (RCT), four case series and two case reports) were included in the review (n=63 patients).

Clinical cure was observed in 54 patients (86%). Bacteriological eradication occurred in 33 (85%) out of 39 patients for whom the data were available. Bacteriological eradication was observed in 27 (90%) out of 30 patients who had clinical improvement. All-cause mortality occurred in 11 (36%) out of 31 patients for whom the data were available.

Adverse events relevant to aerosolised antimicrobials were glossitis and stomatitis (the number of patients was not reported), and bronchospasm (one patient).

The very limited data precluded any strong conclusions. Inhaled antimicrobial monotherapy for pneumonia might be an option in certain cases, when systemic access is unavailable, or denied by the patient, or cannot be used due to systemic toxicity or limited bioavailability in the lungs.

The review question was broadly defined in terms of the participants and interventions of interest. The authors searched a number of relevant databases for published but not unpublished studies, introducing the potential for publication bias. The authors did not state whether language restrictions were applied in the search, which made it difficult to assess the risk of language bias. Methods to minimise errors and biases in the review process were not reported. A formal validity assessment was not carried out. A narrative synthesis was appropriate given the diversity of included studies. The authors' cautious conclusions reflected the evidence presented. However, lack of study quality assessment and other methodological concerns suggest that the authors' conclusions may not be reliable.

Practice: The authors did not state any implications for practice.

Research: The authors stated that future studies should evaluate the concentration of inhaled antimicrobial agents in the epithelial lining fluid, as well as their concentration in the blood after inhalation, and they encourage clinicians to publish any relevant experience.

No external funding.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.