Reappraisal of Pseudomonas aeruginosa hospital-acquired pneumonia mortality

Patients suffering from hospital-acquired pneumonia caused by a type of bacteria that is highly resistant to virtually all antibiotics are twice as likely to die as patients infected with other, less resistant bacteria.

A study published today in the journal Critical Care shows for the first time that the highly resistant, metallo-beta-lactamase-producing Pseudomonas aeruginosa is associated with a much higher mortality rate than other types of the bacteria in patients with hospital-acquired pneumonia. The authors conclude that this may be due to the use of inappropriate antimicrobial treatments for infections with metallo-beta-lactamase-producing P. aeruginosa, and suggest that therapeutic approaches should be reviewed in hospitals with high prevalence of the bacteria.

Alexandre Zavascki from Universidade Federal do Rio Grande do Sul in Porto Alegre, Brazil, and colleagues from other institutions in Brazil studied 150 patients admitted to two hospitals in Porto Alegre and suffering from hospital-acquired pneumonia.

The results of Zavascki et al.'s study show that 42 patients were infected with metallo-beta-lactamase-producing P. aeruginosa. For these patients, the 30-day mortality rate was 57.1%, compared with 29.6% for patients infected with other P. aeruginosa strains. Only half of the patients infected with the highly resistant bacteria were treated with appropriate antibiotics. But even when the recommended treatment was used, mortality was still high, suggesting that the optimal treatment for these highly resistant bacteria is yet to be found.