The use of a coagglutination test to presumptively identify Salmonella typhi in bone marrow-oxgall medium cultures from typhoid fever patients.

A study was conducted to test a coagglutination procedure for detection of Salmonella typhi in bone marrow cultures from suspected typhoid patients admitted to Friendship Hospital, Jakarta, Indonesia. The results of the coagglutination tests were compared to the results from standard cultural isolation and identification. Bone marrow aspirates (356) were cultured in oxgall medium and aliquots subcultured daily for 7 days while simultaneously testing for the presence of Salmonella group D and Vi antigens using coagglutination (COAG). S. typhi was isolated from 220 (62%) of the cultures and the D- and Vi-COAG tests were positive for those same cultures. The COAG test was also negative for 6 cultures containing S. paratyphi A. The COAG results were available within 10 minutes after 18 to 24 hours incubation of the primary cultures whereas the isolation and confirmed identification took 2 to 3 days longer. The COAG test is valuable as an aid to rapidly identify S. typhi in bone marrow-oxgall cultures.