Detection of Chlamydia (Bedsonia) in Certain Infections of Man. I. Laboratory Procedures: Comparison of Yolk Sac and Cell Culture for Detection and Isolation

A total of 37 specimens derived from suspected cases of chlamydial infection, together with appropriate control specimens, were examined for the presence of microorganisms of the genus Chlamydia by 2 different laboratory procedures performed in parallel, namely, 3 passages in cell cultures and 3 passages in yolk sacs. Of 50 tests performed by the cell culture technique, 19 (38%) were positive; of 50 tests in yolk sacs, 5 (10%) were positive. The corresponding figures for clinical specimens alone were 15 of 37 (41%) for cell culture, and 3 of 3 7 (8%) for yolk sac. Most positive tests by either method were first recognized as positive in the initial or in the second passage. Presence of the infectious agent in the cell cultures was detected by recognition of the characteristic inclusion bodies in cells of the inoculated monolayer. Staining with iodine solution or with Giemsa stain gave approximately equal results with the isolates encountered, all of which were of the chlamydial Subgroup A (prototype strain, Chiamydia trachomatis). Approximately half of the specimens tested were fresh; the others had been stored for varying periods at --70 C. In the small number tested it was not possible to detect any reduction in rate of isolation due to storage. In comparison with culture in yolk sac, detection in cell culture was 4 times more sensitive in this series; it is quicker, is relatively unaffected by bacterial contamination, allows measurement of the infectivity of clinical specimens, and has potential logistic advantage.