The real trick is to avoid creating and breathing in an aerosol, which has I'm sure killed more than one researcher before he and his doctor realized what was happening, I heard of one such case in the '70s when I was doing work on E. Coli during a summer program involving salmonella. If you get too much lung tissue---lots of surface area---infected too quickly, well, see pneumonic plague, it's anthrax equivalent, which an Air Force flight surgeon's manual said the first clear diagnostic sign from a patient is his sudden death, etc.
And echoing loxs, it's very unlikely they're working with viable bacteria, if they're just sequencing DNA or the like they're far, far from something viable, and I don't believe it creates spores.