Comparative study of subculture, Gram staining and acridine orange staining for early detection of positive blood cultures.

In view of the importance of a rapid aetiological diagnosis in septicaemia, we compared the results of subculture, Gram staining and acridine orange staining in the detection of positive blood cultures. The study was based on 1013 blood cultures of which 138 were positive by culture. The three techniques were applied 12 h after the specimen was taken in 210 instances, at 24 h in 540 instances and after 48 h in 525. We were able to demonstrate the value of direct examination. Staining with acridine orange yields more positive results than Gram staining and is also simpler.