A method of bacterial count by epifluorescence with acridine orange. Application to skin biopsies performed in burnt patients

: Acridine orange was used for staining and counting micro-organisms obtained from 136 skin biopsies performed in burned patients. The number of organisms per gram of tissue was compared to the number of colony-forming-units (CFU) calculated from cultures of the same biopsies. The staining method was positive in 97 per cent of septic samples, and in 25 per cent of these it proved more sensitive than bacterial cultures, with a 100 to 1000-fold greater number of pathogens detected. Acridine orange also demonstrated bacteria in 69 biopsies which remained sterile after culture. In some cases, the same bacterial species was found in other samples taken a few days later.