A gram stain for smears of blood cultures, body fluids and tissues.

A new Gram stain method for blood cultures was adapted from a method for tissue sections. This was accomplished by comparing various modifications of the latter method on positive smears prepared from a 24-hour negative blood culture seeded with Staphylococcus aureus and Escherichia coli. A blind study was then conducted using the new method and Hucker's method on 24-hour and 72-hour blood cultures as well as a limited number of other body fluids and tissues. Of the 35 positive blood cultures detected by the new method, the Hucker method failed to detect 14 positive specimens (40 per cent) upon initial examination. Ten additional cultures were negative using both stains, but were positive on subculture at three days. The 18 additional cultures positive after ten days were detected using only the Hucker stain.