More recently, S. marcescens has been found to be pathogenic to some people, and it is no longer recommended for use in schools and is not as widely used to track bacterial movement in the environment. S. marcescens has been used to determine the survival and fate of bacteria in saline breast implants. Serratia appears to thrive in saline breast implants, living on the glucose that diffuses across the implant's outer shell. So maybe S. marcescens wasn't the miracle that the Pope expected, but this tiny organism does remind us of the miraculous invisible life that is all around. Bacteria are also called prokaryotes or monerans.
Most bacteria are unicellular, containing only a single cell.
Sometimes bacteria appear multicellular, living together in groups of cells. Bacteria comprise two of the three domains of life, the Eubacteria and the Archaea. A microbe that causes disease is said to be pathogenic. Some believe in transsubstantiation, in which the bread and wine of communion are turned into the presence of Christ. Raphael was born in Urbino, Italy.