The basic idea of this SCP in my mind doesnt really work and it sort of reads like an edgy teen writing a fanfiction about their overpowered OC, more than a clinical review. (apologies if this comes off as mean. I'm autistic and have been told that my critism style isnt the most sensitive so i appologise if this comes off as too mean, it is just my honest opinion). First, a pandemic and an outbreak are not something a disease simply is. An outbreak is simply when a small area contracts a disease or virus, should it spread across the country it would be known as an Epidemic, Only once a disease spreads to multiple countries and continents and is a worldwide Epidemic does it become a Pandemic. a virus or disease that is on it's own is none of these and it feels like you just used those words because they sound smart without actually knowing the meanings. Also if you are trying to sound scientific don't use the term Zombie.
Pathogenic Bacteria are also maybe the least dangerous type of illness you could have thought of as an SCP since this is the same vein of illness as food poisoning. A Virus would be much more threatening. Bacteria also requires a host so how does this SCP not just die off in it's containment cell? how is it contained in the cell? Is it just floating around loose in there? If thats the case then the second you open the door then it is getting out. Why does it have to be in a containment of 15ft exactly? thats a REALLY big cell for something that is litterally microscopic. You also claim that if one of the infected subjects gets out then it is impossible to recontain, but if that's the case how did it get contained in the first place? and why wouldn't just burning them alive work since the one surefire way to kill any form of bacteria is extreme heat?
The way this is written to me sounds like you are the type of person that believes something has to be super super dangerous and require the most ridiculous security to contain in order to be cool when that isn't the case. You gave me criticism on my SCP so i thought i would return the favour (though it may seem like my criticism is trying to be harsh it isnt, i'm just not very good at being sensitive unfortunately, it isn't something I can really help.) what great or year are you in in school/college or whatever schooling system they have where you live? if you like I'd be happy to give you some tips and help you develop your ideas. Again, this is not intended to be a meanspirited and offensive critique but i do really appolagise if it comes off that way.