Gram staining with an automatic machine

This study was undertaken to develop a new Gram-staining machine controlled by a micro-controller and to investigate the quality of slides that were s tained in the machine. The machine was designed and produced by the authors . It uses standard 220 V AC. Staining, washing, and drying periods are cont rolled by a timer built in the micro-controller. A software was made that c ontains a certain algorithm and time intervals for the staining mode. One-h undred and forty smears were prepared from Escherichia coli, Staphylococcus aureus, Neisseria sp., blood culture, trypticase soy broth, direct pus and sputum smears for comparison studies. Half of the slides in each group wer e stained with the machine, the other half by hand and then examined by fou r different microbiologists. Machine-stained slides had a higher clarity an d less debris than the hand-stained slides (p < 0.05). In hand-stained slid es, some Gram-positive organisms showed poor Gram-positive staining feature s (p < 0.05). In conclusion, we suggest that Gram staining with the automat ic machine increases the staining quality and helps to decrease the work lo ad in a busy diagnostic laboratory.