Thanks for this! I originally thought that indications of bacteria in the CNS were PCR (polymerase chain reaction) artifacts (BTW, PCR has an interesting history - potential subject for your pub?) but this puts the lie to that.
From what I've read, digging into the blood brain barrier, I wouldn't call the CNS 'sterile'; it's more of a semi-separated immunological space. There's evidence that T-cells and macrophages can pass the BBB. I've seen nothing indicating that astrocytes might go the other way. On a mobile, but I plan to dig into that study when I get to a bigger screen. (reading a study on a phone is an exercise in frustration)