Can empiric broad-spectrum antibiotics for ventilator-associated pneumonia be narrowed based on Gram’s stain results of bronchoalveolar lavage fluid

Background Although Gram’s stain (GS) of bronchoalveolar lavage fluid is routinely obtained, its usefulness remains unclear. Our purpose was to assess the value of the GS in diagnosing ventilator-associated pneumonia (VAP) and to determine whether early antibiotic narrowing was feasible. Methods Retrospective study of critically ill surgical patients with clinical and quantitative evidence of VAP. GS and culture data were collated and analyzed. Results GS results correlated with cultured organisms in 60% of cases. Overall accuracy of GS in diagnosing VAP for any organism was 58%. Gram-negative rod staining yielded like pneumonia at a statistically higher rate than Gram-positive cocci. A lack of bacteria on GS demonstrated no growth on culture 26.5% of the time, revealing the poorest correlation of all. Conclusions GS cannot be a reliable surrogate for quantitative culture. Altering antibiotic therapy based on GS could lead to inappropriate therapy and, presumably, greater morbidity and mortality.