We showed the usefulness of gram-stained sputum obtained just after administration of ampicillin or ceftriaxone as the earliest therapeutic indicator for evaluating the effectiveness of the empiric therapy in community-acquired pneumonia caused by pneumococcus or Moraxella ctarrhalis. The main paremeter confirming the effectiveness was the significant reduction in the number of pathogenic organismus 1 hour after the completion of the first dose, which was also showen by the reduced size of cocci or loss of a gram-positive appearance. The reduction in the number was more obvious 12h after completion of the first dose and before the second dose of the empiric therapy.This would avoid the routine use of broad-spectrum antimicrobial agents.
(J Infect Chemother(2013) 19:517-523)
Gram stein is a useful technique in detecting bacteria, but it generally believed not to be useful to detect tubercle bacilli in clinical samples. Mycobacterial tuberculoses generally need a special staining as the Ziehl-Neelsen to be detected. We also showed cases in which Mycobacterial tuberculoses infection were firstly suggested by the Gram stein- evaluation of their sputum ,pus and liquor , confirmed by the following the Ziehl-Neelsen staining and diagnosed by PCR or culture.
(J Infect Chemother. 2011 Aug;17(4):571-4.The usefulness of changing focus during examination using Gram staining as initial diagnostic clue for infective tuberculosis.)
(J Infect Chemother. 2012 Dec;18(6):931-6.Case of Mycobacterium tuberculosis meningitis: Gram staining as a useful initial diagnostic clue for tuberculous meningitis.)