Role of inhaled antibacterials in hospital-acquired and ventilator-associated pneumonia.

Inhaled antibiotics are not usually considered outside the setting of cystic fibrosis or Pneumocystis jiroveci prophylaxis. However, because they deliver high drug concentrations at the site of infection with negligible systemic absorption and toxicity, they are logical compliments to standard intravenous therapy for severe nosocomial pneumonias -- particularly those caused by multiresistant organisms. Older studies that have shown marginal or no benefit have either applied inhaled antibiotics indiscriminately to low risk populations, or have used crude delivery systems, such as hand atomizers or poured it into the endotracheal tube. Although inhaled antibiotics cannot be recommended for prevention of nosocomial pneumonia at this time, a few studies involving prophylaxis have shown promising trends, particularly in high-risk patients with predisposing conditions. The greatest potential of inhaled antibiotics lies in the treatment of severe healthcare-associated pneumonia caused by a multiresistant organism. The method of delivery is extremely important. Trials that have shown the most benefit, even against pathogens most difficult to eradicate and in damaged lungs, have used optimized delivery systems. Most authorities recommend using ultrasonic or vibrating disk nebulizers to generate particle sizes between 1 and 5 microm that are crucial for deposition in terminal bronchioles and alveoli. Inhaled liposomal amphotericin has also demonstrated encouraging results in animal trials. Recently, inhaled phytochemicals were successfully employed in the treatment of a patient with primary pulmonary tuberculosis. When used selectively in high-risk patients, or in the treatment of established pneumonia, inhaled antibiotics have not been associated with development of resistant organisms.