What selective culture medium is most widely used for isolating Streptococcus mutans:____________?
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Answer: B. Mitus salivarius bacitracin agar
Explanation
Mitis Salivarius Bacitracin agar is a selective culture medium widely used for isolating Streptococcus mutans. Bacitracin added to the Mitis Salivarius base inhibits the growth of other competing oral bacterial flora. This selective formulation allows laboratories to quantify Streptococcus mutans colonies from dental plaque samples. Streptococcus mutans is a primary bacterial pathogen heavily implicated in the initiation of dental caries. Selective media utilize specific chemical inhibitors and antibiotics to isolate target organisms from complex microbial ecosystems. Colonies of Streptococcus mutans typically display characteristic morphology on MSB agar after incubation.
Microbial counts obtained using this agar help clinicians assess a patient's individual caries risk profile. Preventive dental programs utilize caries risk testing to design targeted dietary and antimicrobial intervention strategies. Research studies rely heavily on selective culture techniques to monitor oral microbial shifts during clinical trials. MacConkey medium is a selective and differential agar used primarily for isolating gram-negative enteric bacilli. Nutrient agar is a general-purpose growth medium lacking selective inhibitors required for isolating specific oral pathogens. Tellurite medium is specifically formulated for isolating Corynebacterium diphtheriae rather than oral streptococci.
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