Microbiology and Immunology

American Type Culture Collection WORLD OF MICROBIOLOGY AND IMMUNOLOGY

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Those infected with the parasite may develop the severe

symptoms listed above, a milder condition characterized by

nausea, loose bowel movements and pain in the abdomen, or

sometimes no symptoms at all. The latter is a concern to oth-

ers, as the asymptomatic person can still pass the parasite in

his/her feces and so potentially spread the infection to others.

Indeed, such transmission can persist even years after expo-

sure to the parasite.

Entamoeba histolyticacan occur in two forms. The

parasite is excreted to the environment as a so-called cyst

from. This form is very hardy, and is analogous to a bacte-

rial spore. This form is designed for longevity, to preserve

the genetic material of the parasite when in inhospitable

environments. Once in a more favorable environment, such

as the intestinal tract of humans, the cyst resuscitates and

growth resumes. The active and growing form of the parasite

is known as a trophozoite. It is the trophozoite that causes the

symptoms of amebiasis. Some trophozoites will re-encyst

and exit via the feces, to become a potential source of further

infection.

If the cyst stays in the intestinal tract after being

ingested then they have little adverse effect. However, if the

cysts invade the walls of the intestine, ulcers and diarrhea can

be produced. Amebiasis can be fairly short in duration, lasting

only a few weeks. Or, the infection may become chronic. The

chronic form can be ominous, as the trophozoite can invade

the blood and be carried all over the body. The abscesses

formed in the liver and brain can be very destructive.

Both amebiasis and the causative parasite have been

known for a long time. The parasite was described in great

detail and given its name in 1903. Despite this long history, the

diagnosis of the malady still relies on the visual detection of

the parasite in fecal material obtained from a suspected

patient. Often fecal samples need to be examined for several

days to detect the presence of cysts. Amebiasis is still easily

misdiagnosed, especially when no symptoms are present. Also

the parasite can be visually similar to harmless normal resi-

dents of the intestinal tract, such as Entamoeba coli, and can

co-exist with bacteria that themselves are the cause of the

symptoms being experienced by the infected person.

Amebiasis is treatable, usually by a combination of

drugs. An amebicide will kill the organisms in the intestinal

tract, while an antibiotic will treat any bacteria that have been

ingested with the feces, contaminated water, or food. Finally,

if warranted, a drug can be administered to retard the spread

of the infection to tissues such as the liver.

See alsoParasites

AAmerican Type Culture CollectionMERICANTYPECULTURECOLLECTION

The American Type Culture Collection, which is also known

as the ATCC, is a not-for-profit bioscience organization that

maintains the world’s largest and most diverse collection of

microbiological life. Many laboratories and institutions

maintain their own stockpile of microorganisms, usually

those that are in frequent use in the facility. Some large cul-

ture collections are housed and maintained, usually by uni-

versities or private enterprises. But none of these rivals the

ATCC in terms of size.

The ATCC collection includes repositories of bacterial

species, animal viruses, cell lines (which are important for the

growth of certain types of viruses), fungi, plant viruses, pro-

tists(microscopic organisms that have a nucleusthat is con-

tained within a membrane), and yeasts. As well, in conjunction

with researchers at George Mason University, which borders

the ATCC facility, research in areas such as bioinformaticsis

carried out.

The ATCC was founded, and continues to function, to

acquire, confirm the identity of, preserve and distribute bio-

logical materials to scientists worldwide. Since its inception,

the mandate has expanded to now include information tech-

nology and intellectual property. Today, in addition to offering

the microbiological organisms for sale, the ATCC offers tech-

nical services and educational programs to academic, govern-

ment, and private organizations.

The genesis of the ATCC began in 1921. Then, the

Army Medical Museum accepted a then renowned culture

collection called the Winslow Culture Collection. The col-

lection was put under the care of the Washington, D.C. mem-

bers of the Society of American Bacteriologists (in time, this

society grew in scope and membership to become the

American Society for Microbiology). In 1925, the ATCC

became an official entity with its incorporation. The bur-

geoning culture collection was moved to the McCormick

Institute in Chicago. Twelve years later the collection

returned to Washington. Space was leased to house the col-

lection. Over the years the increasing diversification of the

ATCC and the acquisition of more cultures taxed the space,

so a series of moves to larger and larger sites occurred.

Finally, in 1998, the organization moved to the state-of-the-

art facility it continues to occupy.

Technician at The American Type Culture Collection.

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