Which Statement Regarding the Gram Stain Is FALSE

Multiple Choice

Which statement regarding the Gram stain is FALSE?

A) A Gram stain may give sufficient information to start appropriate antibiotic treatment-for example a Gram-positive diplococcus in sputum is likely to be Streptococcus pneumoniae.
B) A Gram stain can sometimes be used to make a diagnosis-for example a Gram-negative diplococcus in WBC from urethral discharge is Neisseria gonorrhoeae.
C) Gram staining can be used to differentiate intestinal normal microbiota from pathogens-for example differentiating E. coli from Salmonella enterica.
D) In most cases, Gram staining is not sufficient to identify an organism-for example, Gram-positive staphylococci on skin may be either S. aureus or S. epidermidis.
E) Medically important bacteria can seldom be identified by Gram staining alone-for example the throat may harbor Streptococcus pyogenes (pathogen) as well as Streptococcus species that are normal microbiota.