Bites from the brown recluse spider (see photo left) can be pretty nasty, and produce tissue damage similar to a typical MRSA skin and soft tissue infection. Despite the epidemic of MRSA that’s ongoing in many regions, particularly the US, MRSA infections are still sometimes misdiagnosed as spider bites.
To a degree, I can see why this might happen in areas where the brown recluse spider lives (i.e. the yellow area on the map at right) and where these spider bites certainly occur. Even in these regions though, taking a culture to rule out MRSA is about as simple as it gets. Sadly, erroneous spider bite diagnoses also happen in areas where the brown recluse spider doesn’t even exist.
Does this relate to animals? Not really. Unlike people, animals rarely develop the type of skin infection that mimics a spider bite, so misdiagnosis as a spider bite is unlikely (although it does sometime occur). Failure to properly consider MRSA and test for it is still a problem in animals.
Source of images: http://en.wikipedia.org/wiki/Brown_recluse_spider