[Physicochemical changes in hemoculture media related to blood]

Inoculation of sterile blood into a blood culture medium causes changes of some physicochemical properties, whose maintenance is necessary for growth of fastidious micro-organisms. During incubation of these media at +37 degrees C, red cells utilize glucose for their metabolism, causing acidification and increase of carbon dioxide partial pressure, while oxygen partial pressure tends to decrease during first days of incubation, and increase after. Experimental conditions (choice of medium, volume of blood incubates, ventilation, glucose concentration) notably modify these results. This work underlines the necessity for a greater standardization of media and of technical conditions, in execution of blood cultures.