This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American Quick, can you describe your grandparents?

Gram-positive bacteria show blue or purple after Gram-staining in a laboratory test. They have thick cell walls. Gram-negative bacteria show pink or red on staining and have thin walls. They release ...

CHAMPAIGN, Ill. — Scientists have labored for decades to find antibiotics that work against Gram-negative bacteria, which cause some of the deadliest infections in hospital settings and are most ...

We often hear about bacteria, but what exactly are they? A bacterium is a living organism that consists of a single cell (unicellular). It has ...

There are many ways of classifying bacteria. One method is based on the cell membrane. In 1884, a bacteriologist named Christian Gram created a test that could determine if a bacterium had a thick, ...