They may even use harmless bacteria as a transport link to arm other harmful bugs that pass by.

FORBES: Germ Warfare

The harmless bacteria - belonging to the Bacillus genus - then feed on the nutrients to produce limestone.

BBC: Key test for re-healable concrete

There is no need to panic, however: the creatures in question are harmless bacteria that were found preserved in a crystal of rock salt.

ECONOMIST: Old salts

It's using bacteria-hating (and thankfully harmless) viruses as biosensors to quickly identify superbugs, or antibiotic-resistant bacteria that can sometimes prove fatal.

ENGADGET

Then anaerobic bacteria take that nitrate and turn it into harmless nitrogen gas.

FORBES: Page 2 of 2

These creatures, now called anammox bacteria, transform caustic and hazardous ammonium into dinitrogen, the harmless nitrogen gas that makes up 78% of the air we breathe.

FORBES: Magazine Article

They found that 48 percent of beverages obtained from soda fountains contained coliform bacteria, 11 percent contained E. coli (which are mostly harmless, but some can cause diarrhea, urinary tract infections, respiratory illness and pneumonia), and 17 percent had Chryseobacterium meningosepticum (which could sicken newborns or adults with weakened immune systems).

CNN: Soda fountains contained fecal bacteria, study found