It's a mistake. You can 'be interested in something' or 'be interested by something'. You cannot use replace 'in' or 'by' with 'with'. I googled 'be interested with something', and the only instances I found were non-native errors and language-related queries similar to this one. You have to be careful when looking for examples online. Sometimes you come across sequences of words which appear to be examples of non-existent collocations. For example: "How can I keep my kids interested in their schoolwork when we're stuck at home?" "You could keep them interested with games, quizzes and puzzles." The above conversation is a perfectly valid sequence of words where 'interested' is followed by 'with', but it's obviously not a parallel example to 'be interested in something'. The adverbial phrase 'with + noun' is not the object of 'interested.' I hope that helps.

Agree with Tangestone -- native speakers of English never say "interested with." It is always "interested in." You rarely hear "interested by" in American English -- that may be a British thing.

I have never used "interested with" in decades as a native English speaker. Odd that you would find such disagreement...but it IS the Internet!