In French, how do you express a pair of interrogative pronouns "which" and "what"?

Question

In English, we often use a pair of interrogative pronouns – in this specific instance, "which" and "what" – to express the idea of:

Which antibiotic works best against what type of infection – you need to have that knowledge under your belt.

German and Russian also uses the combination of two interrogative pronouns, "welche & welche" and "какой & какой", respectively in an instance like this.

On the other hand, I just realised that this "which & what" perhaps might not translate well into French as "quel & quel":

{???}: Quel antibiotique sera plus efficace contre quel type d'infection : voilà ce qu'il te faut connaître.

I wonder if it sounds more idiomatic to say:

Quel antibiotique sera plus efficace contre tel type d'infection : voilà ce qu'il te faut connaître.

Answer 1

Les deux phrases en français sont correctes mais n'ont pas la même signification. Tel réfère à une partie des infections alors que quel n'en détermine aucune en particulier. On pourrait remplacer Quel antibiotique sera plus efficace contre tel type d'infection par Quel antibiotique sera plus efficace contre ce/ces type d'infection. La première forme avec quel et quel me paraît donc la meilleure traduction.

Answer 2

It is idiomatic to say

Quel X pour quel Y

For example it would be fine to say:

Quel antibiotique pour quel type d'infection : ...

It's also possible to say something like:

Quel antibiotique fonctionne le mieux contre quel type d'infection : ...

However, personally I find this second construction quite heavy; maybe too many words between the two quels?

Finally the following also works:

Tel antibiotique pour telle infection : ...

...which corresponds to the English "such antibiotic for such infection", i.e. it implicitly invokes a random example rather than a choice.