Biomarkers to optimize antibiotic therapy for pneumonia due to multidrug-resistant pathogens.

No currently available biomarker can be used as a diagnostic marker for ventilator-associated pneumonia due to multidrug-resistant pathogens. Procalcitonin can be used to customize the duration of antimicrobial treatment without excess morbidity and mortality: when its concentration is less than 0.5 ng/mL or has decreased by 80% or more compared with the peak concentration, antibiotics can be stopped. With this strategy, extreme vigilance must be maintained after terminating antimicrobial therapy to detect a recurrent infection.