Boots RJ. et al

About this article: "Surveillance cultures to help VAP treatment is a matter of debate in this prospective study surveillance cultures had a sensitivity of 25% and a specificity of 50% in microorganisms predicting VAP. However, the conclusion of the study is that surveillance cultures can not replace diagnostic samples."

Boots RJ, Phillips GE, George N, Faoagali JL. Department of Intensive Care Medicine, Royal Brisbane and Women's Hospital, and Burns, Trauma and Critical Care Research Centre, The University of Queensland and Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia. Respirology. 2008 Jan;13(1):87-96. PMID: 18197916

Background and objectives: Surveillance cultures may improve the prediction of ventilator-associated pneumonia (VAP) and empirical antibiotic selection. This study examined the utility and patient safety of blind, non-protected, low-volume mini-bronchial lavage (BM-BAL) surveillance cultures in predicting VAP.

Methodology: A prospective, cohort study was performed in a large general intensive care unit. BM-BALs were collected within 12 h of admission then thrice weekly. Each BM-BAL was screened by Gram staining for intracellular organisms and then quantitatively cultured. VAP was diagnosed using the Clinical Pulmonary Infection Score. The concordance for isolates from the BM-BAL was assessed against concurrently collected endotracheal aspirates (EA). Results: Four hundred and twelve patients requiring a minimum of 48 h of mechanical ventilation were enrolled. Fifty patients developed 58 episodes of VAP. Concordant pathogens were found in 85% of BM-BAL specimens collected 2 days prior to VAP onset. Their antibiograms were stable over the preceding 4 days. The isolation of pathogens with colony counts >/=10(4) cfu/mL from BM-BAL performed 2 days prior to the clinical onset of VAP had a sensitivity of 84%, specificity of 50%, positive predictive value of 31% and a negative predictive value of 93% for predicting the development of VAP. BM-BAL WCC, quantification of bacterial growth and the percentage of intracellular organisms were not helpful in predicting VAP diagnosis.

Conclusions: BM-BAL surveillance cultures are well tolerated and useful in predicting the pathogens and their antibiograms causing VAP. Diagnostic specimen collection at the time of VAP onset is still required as surveillance cultures may be negative even one day prior to VAP onset.