If it is true "folliculitis" then the offending agent is likely staph. If it is recurrent and the lesion is mistakenly called folliculitis, then you should start thinking of STD related infections such as HSV & syphillis to name a few.
Don't forget MRSA its on the rampage out west and can lead to abscess and recurring sores that just don't heal. Also I've seen people misdiagnosed c folliculitis and actually have molluscum.