Controversies in the diagnosis of ventilator-acquired pneumonia

The threat of selection for antibiotic resistant microorganisms places physicians managing ventilator-associated pneumonia in the position of balancing seemingly contradictory goals-prompt, appropriate treatment of pneumonia while restricting use of broad-spectrum antibiotics. The diagnostic strategy-whether quantitative or qualitative, invasive or noninvasive-influences the appropriateness of antibiotic therapy and the ability to withhold or withdraw antibiotics in patients without pneumonia. Generally, quantitative cultures lead to greater ability to safely withhold or withdraw antibiotics than qualitative cultures. No clear differences in management result from the use of different methods to obtain specimens for quantitative culture. Choice of diagnostic strategy should be individualized to the specific clinical scenario for optimal results.