Virus or Bacterium?

Dr. David M. Carlberg

Professor of Microbiology

Dept. of Biological Sciences

California State University

Long Beach, CA

To the Editor:

I very much enjoyed your excellent report on the E.coli epidemic in Japan in the September issue (“Japan Battles E.coli `Epidemic,` ” page 1). However, I noticed that you had a small problem deciding whether E.coli is a virus or a bacterium.

May I suggest that you obtain a copy of my book, Cleanroom Microbiology for the non-microbiologist, [Interpharm Press, Buffalo Grove, IL; (847) 459-8480]. The book was written to help people who have little biological science background through some microbiological basics.

Editor`s Note: We do have to eat our words this time–E.coli is a bacterium and not a virus as so many of our readers pointed out to us. We did get a copy of Professor Carlberg`s book and, we would definitely recommend it to anyone who is working in a cleanroom and is a microbiology novice. According to Dr. Carlberg, “Bacteria constitute a large group of thousands of species of single-celled organisms. Because they appear to be the most numerous type of microorganism in soil and on the body, they are probably the most common microbial contaminant in cleanrooms.” On the other hand, viruses are “noncellular infectious particles. Their structure is extremely simple, frequently consisting of nothing more than a single molecule of either DNA or RNA (but never both) wrapped with a protein coat, called a CAPSID… Viruses are obligate intracellular parasites, which means they must find an appropriate host cell in which to multiply.” Dr. Carlberg`s book also contains a chapter on “Detection and Enumeration of Micro- organisms in the Cleanroom.”