Administration of antibiotics via the respiratory tract as monotherapy for pneumonia

There is increasing interest in applying alternatives to the systemic modes of administration of antimicrobial agents for the treatment of patients with pneumonia. We endeavored to accumulate and evaluate the published evidence on the role of aerosolized antimicrobials administered as monotherapy for patients with pneumonia through searches of PubMed, Scopus and relevant bibliographies. Seven relevant studies (one randomized controlled trial, four case series and two case reports), including 63 patients, were identified; 37% (23 out of 63) and 63% (40 out of 63) of these patients suffered from community-acquired and nosocomial (including ventilator-associated) pneumonia, respectively. Acinetobacter baumannii (41%), Gram-positive cocci (37%) and Pseudomonas aeruginosa (16%) were the pathogens most frequently isolated from sputum, tracheal aspirates, bronchoalveolar lavage and bronchial brush specimens. Colistin (49%), penicillin (37%) and aminoglycosides (17%) were the antimicrobials administered via the respiratory tract. Concurrent systemic antimicrobials (without activity against the isolated pathogens) were given to 33% (21 out of 63) of patients. Clinical cure and bacteriological eradication from the aforementioned specimens were observed in 86% (54 out of 63) and 85% (33 out of 39) of patients, respectively. For the 31 patients for whom data were available, all-cause mortality and attributable mortality were 36% (11 out of 31) and 10% (three out of 31), respectively. The very limited published data preclude any strong conclusions; however, the available data seem to suggest that aerosolized antimicrobial monotherapy for pneumonia should not be a priori excluded when systemic access is unavailable, denied by the patient or when concerns exist regarding bioavailability in the lungs or systemic toxicity. Clinicians are encouraged to publish any relevant experience in order for a considerable body of literature to be accumulated.