This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Microbiology
Chlamydia are isolated by 
Select and explain. 
A. Enzyme immune assay, B. Yolk sac inoculation, C. Direct immunofluorescence, D. Microimmunofluorescence
B: Yolk sac inoculation
Answer: B: Yolk sac inoculation 
Explanation: Isolation of chlamydiae can be done by :Inoculation into yolk sac/embryonated eggs of 6-8 day old chick embryo which may be pretreated by streptomycin or polymyxin B.Inoculation into experimental animals (mice)Tissue/cell culture:Preferred modeCommonly used cell lines are McCoy and HeLa cells.Cell cultures are pretreated by irradiation or chemicals such as 5-iodo-2 deoxyuridines or cycloheximide to enhance replication and detection of inclusion bodies.Pretreatment with DEAE dextran or centrifugation after inoculation promotes contact between chlamydiae paicles and cell monolayer.