Which medium is traditionally used to isolate Bordetella pertussis?

Which medium is traditionally used to isolate Bordetella pertussis?

• A. Bordet-Gengou agar
• B. MacConkey agar
• C. Sabouraud agar
• D. Thioglycolate broth

Answer: (A)

Bordetella pertussis is a fastidious organism that needs a nutrient-rich, selective environment to grow while keeping other microbes at bay. Bordet-Gengou agar provides exactly that: a potato infusion base with glycerol and blood enrichment that supports the delicate bacterium and yields visible colonies after several days. This medium was developed specifically to encourage pertussis growth and to help separate it from contaminating flora in clinical specimens. Other media listed aren’t suitable for isolating this organism—MacConkey agar targets enteric bacteria and isn’t supportive for pertussis; Sabouraud agar is for fungi; Thioglycolate broth is used mainly for assessing oxygen tolerance and anaerobes—so they don’t provide the right conditions to isolate Bordetella pertussis. Thus, Bordet-Gengou agar is the traditional choice.

Bordetella pertussis is a fastidious organism that needs a nutrient-rich, selective environment to grow while keeping other microbes at bay. Bordet-Gengou agar provides exactly that: a potato infusion base with glycerol and blood enrichment that supports the delicate bacterium and yields visible colonies after several days. This medium was developed specifically to encourage pertussis growth and to help separate it from contaminating flora in clinical specimens. Other media listed aren’t suitable for isolating this organism—MacConkey agar targets enteric bacteria and isn’t supportive for pertussis; Sabouraud agar is for fungi; Thioglycolate broth is used mainly for assessing oxygen tolerance and anaerobes—so they don’t provide the right conditions to isolate Bordetella pertussis. Thus, Bordet-Gengou agar is the traditional choice.