Well, according to Dr. Hooper, the bacteria was named after greek sorority or fraternity at Virginia Polytech. Here's the link to her talk (4.10 - 4.35)
https://www.youtube.com/watch?v=PElM1QIIoNU
But the fact that they form greek letter structures and hence named so, makes more sense!
Who am I to argue with dr Hooper:-)? If she says it is Virginia Polytech it means it is Virginia Polytech unless I get hard evidence it is otherwise. Thanks for reply!!!