A researcher is asked to determine if a sample contains Neisseria meningitides. Knowing Neisseria meningitides is slow growing and other foreign microbes may also be present in the culture, which type of media would be best suited?单项选择题
A
Differential media
B
Selective media
C
Growth media
D
Selective and Differential media

Question

A researcher is asked to determine if a sample contains Neisseria meningitides. Knowing Neisseria meningitides is slow growing and other foreign microbes may also be present in the culture, which type of media would be best suited?单项选择题

A

Differential media

B

Selective media

C

Growth media

D

Selective and Differential media

BlackTom AI · Accepted Answer

Starting with option 1: Differential media. Differential media allow observation of visible changes in colony characteristics to distinguish organisms, but they do not inhibit growth of unwanted microbes. Given that Neisseria meningitidis is slow-growing and the sample may contain other foreign microbes, differential media alone might let competing organisms grow and obscure results.

Option 2: Selective media. Selective media contain agents that inhibit the growth of some microorganisms while allowing others to grow, which helps when the target organism is present in a mixed culture. However, using only selective media will not provide distinguishing features to identify Neisseria meningitidis among the organisms that are able to grow; additional testing would still be required to differentiate.

Option 3: Growth media. General growth (nutrient) media support the growth of many organisms without inhibiting contaminants and without providing differentiation. This would not address the challenge of slow growth or the mixed culture, making identification unreliable.

Option 4: Selective and Differential media. This combination is ideal here: selective components suppress competing microbes, reducing contamination and speeding up detection of the target organism, while differential components reveal characteristic colony traits (such as color changes or informative halos) that help identify Neisseria meningitidis among the survivors. This dual approach addresses both the need to limit growth of non-target organisms and to differentiate Neisseria meningitidis from others, making it the most suitable choice in this scenario.