v.: intravenous; GFR: glomerular filtration rate; MDRD: Modification of Diet in the Renal Disease; MIC: minimum inhibitory concentration; selleck chem NAs: nephrotoxic antimicrobials; NSAID: nonsteroidal anti-inflammation drug; ORs: odds ratios; RIFLE: Risk Injury-Failure-Loss-End-stage kidney disease; ROC: receiver operating characteristic; SAPS II: Simplified Acute Physiology Score II; Scr: serum creatinine; VAP: ventilator associated pneumonia; XDR: extensively drug-resistantCompeting interestsThe authors have no competing interests to declare relative to this article.Authors’ contributionsMR, LM, EA, MV, PP and MA designed the study. AL, MV, GR and GDP collected and assembled the data. LM and EA performed the statistical analysis. MR, LM, MA, EA, PP and AL drafted the manuscript, and all authors have read and approved the final manuscript.

AcknowledgementsThe authors thank Dr. Alessandra Giordano for her scientific support. Marian Everett Kent received payment from the authors for editing portions of the manuscript.
Because survival is improved in the patients receiving appropriate empirical antibiotics, guidelines recommend the coverage of all potential pathogens responsible for an episode of ventilator-associated pneumonia (VAP) [1,2]. Collection of blood and bronchial specimens precedes the administration of empirical antibiotics. The choice of antibiotics is based on the presence of specific risk factors [2]. After the responsible bacteria in samples were identified, guidelines recommend reassessing the antibiotic treatment [2].

Although safe, this strategy exposes the patient to an overuse of broad-spectrum antibiotics [3]. Overuse of antibiotics results in an increase in multidrug resistant pathogens, treatment-related side effects and increased cost of hospitalization. Use of biomarkers, for instance, procalcitonin, failed to be effective in septic ICU patients in deciding whether or not to start antibiotics [4]. The Gram stain of bronchial sputum is not safe enough to use in deciding whether or not to start an antimicrobial treatment [5]. With regard to methicillin-resistant Staphylococcus aureus (MRSA), this strategy leads to a wide use of vancomycin or linezolid [6]. These antibiotics are associated with side effects and increased costs [6].A rapid detection of resistant bacteria can avoid the use of unnecessary antibiotics [7].

Because VAP due to MRSA has been associated with increased mortality [8], the detection test should have an excellent negative predictive value. New diagnostic tests using real time polymerase chain reaction (RT-PCR) detect pathogens in approximately 60 minutes [9]. They can detect both methicillin-susceptible Staphylococcus aureus (MSSA) and MRSA in blood, nasal and surgical site secretions. Entinostat To date, these tests have been poorly assessed in bronchial secretions of patients with suspected VAP.