A sputum Gram stain is a laboratory test used to detect bacteria in a sputum sample. Sputum

is the material that comes up from your air passages when you cough very deeply.The most

common pathogens detected with a sputum culture are bacteria such as Streptococcus

pneumoniae, Haemophilus influenzae, Staphylococcus aureus, and Klebsiella species