<prompt> Gram staining of the sputum of the patients with pneumonia is diagnostic with all these pathogens, EXCEPT:S. pneumoniaeS. aureusGram-negative bacteriaCoxiella burnetii  <response>: Grams staining may identify ceain pathogens e.g., S. pneumoniae, S. aureus, and gram-negative bacteria by their characteristic appearance. A sputum sample must have 1. 25 neutrophils 2. 10 squamous epithelial cells per low-power field, to be adequate for culture. Ref: Harrison, E-18, P-2133 