Question:medium
Isolation of Chlamydia from a tissue specimen can be done by:
Isolation of Chlamydia from a tissue specimen can be done by:
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Isolation means growing the organism; Chlamydia needs living cells like the egg yolk sac.
Updated On: Jun 24, 2026
- ELISA (enzyme linked immunosorbent assay)
- Yolk sac inoculation
- Direct immunofluorescence antibody test (DFA)
- Polymerase chain reaction (PCR)
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The Correct Option is B
Solution and Explanation
The trick here is the precise meaning of isolation, which means growing the organism, not merely finding its parts.
Biology of Chlamydia: These are obligate intracellular bacteria. They have an energy parasite lifestyle and cannot multiply outside a host cell, so artificial agar will not grow them. To isolate them you must provide living cells.
Available living systems: The two traditional ways to culture Chlamydia are inoculation into the yolk sac of an embryonated egg and inoculation into susceptible cell lines like McCoy cells. Of the choices given, only yolk sac inoculation is such a growth method.
Why detection tests do not count: An ELISA picks up chlamydial antigen, a DFA stains elementary bodies with a labeled antibody on a slide, and a PCR amplifies chlamydial DNA. All three confirm presence but none recovers a viable organism, so none qualifies as isolation.
Therefore the correct isolation method is yolk sac inoculation.
\[\boxed{\text{Yolk sac inoculation}}\]
Biology of Chlamydia: These are obligate intracellular bacteria. They have an energy parasite lifestyle and cannot multiply outside a host cell, so artificial agar will not grow them. To isolate them you must provide living cells.
Available living systems: The two traditional ways to culture Chlamydia are inoculation into the yolk sac of an embryonated egg and inoculation into susceptible cell lines like McCoy cells. Of the choices given, only yolk sac inoculation is such a growth method.
Why detection tests do not count: An ELISA picks up chlamydial antigen, a DFA stains elementary bodies with a labeled antibody on a slide, and a PCR amplifies chlamydial DNA. All three confirm presence but none recovers a viable organism, so none qualifies as isolation.
Therefore the correct isolation method is yolk sac inoculation.
\[\boxed{\text{Yolk sac inoculation}}\]
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