Identification of the presence and type of biliary microflora by immediate gram stains.

Immediate gram stains were performed on gallbladder bile aspirated at the start of an operation for biliary disease in 191 consecutive patients undergoing elective biliary surgery. The results of the gram stains were telephoned to the operating theater within 20 minutes of collection. The over-all accuracy rate of the telephone gram stain reports compared with the subsequent bile cultures was 77 percent. The incidence of false-positive results was 12 percent, and false-negative results were recorded in 7 percent. The organism was identified wrongly by the gram stain in 4 percent of patients. These results have improved with experience and the over-all accuracy rate of gram stains on bile over the last 6 months have been 87 percent.