TIPSHEET April 1997
Highlights from the Journals of the American Society for Microbiology
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Jim Sliwa (202) 942-9297 [email protected] **************************************************

DONATED ORGANS SHOULD BE TESTED FOR

AMEBAE

An undiagnosed, fatal infection could contaminate organ donations and prevention strategies need to be developed , say researchers from the Centers for Disease Control and Prevention in the April 1997 issue of the Journal of Clinical Microbiology.

The researchers report a case study of an 11-year-old boy who died of what was thought at the time to be bacterial meningitis. No autopsy was performed and his kidneys and liver were donated after his death. It was later determined, after another death in the area, that the ultimate cause of death was an amebic infection known as Naegleria fowleri. None of the organ recipients received any preventive treatment, none developed subsequent infections and all the transplanted organs functioned well.

"Presently, no practical test is available to ensure that donor organs are free from amebae, and no prophylactic drug regimen to treat recipients has been established," say the researchers. "While no subsequent infections occurred in the recipients in this instance, our report illustrates the need for an improved strategy for evaluating the benefits and risks of transplanting tissues from persons whose illness was likely caused by an infectious agent."

(M.H. Kramer, C.J. Lerner and G.S. Visvesvara. 1997. Kidney and liver transplants from a donor infected with Naegleria fowleri. Journal of Clinical Microbiology. 35:1032-1033)

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WHICH CAME FIRST: THE CHICKEN OR THE

MOUSE?

The ultimate source of salmonella infections at poultry farms may not be the birds, say researchers from the U.S. Department of Agriculture and the University of Georgia. It might be the mice.

The researchers report in the April 1997 issue of the journal Applied and Environmental Microbiology a two-phase study of the spleens of 1,147 mice from 21 henhouses. The spleens were tested for salmonella contamination. In addition, eggs from the henhouses were also tested for contamination.

"The results strongly indicate that the mouse is a carrier of invasive Salmonella enterica serovar Enteritidis in the henhouse environment," say researchers. The researchers also note that mouse isolates were able to produce unprecedented amounts of a variant of the bacteria that is associated with more severe infections in chicks and may have an enhanced ability to contaminate eggs.

(J. Guard-Petter, D.J. Henzler, M. Mahbubur Rahman, and R.W. Carlson. 1997. On-farm monitoring of mouse-invasive Salmonella enterica serovar Enteritidis and a model for its association with the production of contaminated eggs. Applied and Environmental Microbiology. 63:1588-1593.)

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NEW INTRANASAL VACCINE FOR INFLUENZA A

Scientists at AVIRON in Mountain View, California, have developed a new live-attenuated vaccine candidate for influenza A that can be administered through the nose. They report their findings in the April 1997 issue of the Journal of Virology.

The researchers developed this vaccine by taking a wild-type influenza A virus (one capable of causing disease) and introducing discrete mutations into its genome to reduce its ability to cause disease. The result is a live attenuated influenza A vaccine candidate suitable for human testing.

Historically, influenza epidemics have been the cause of severe morbidity and mortality, especially in the elderly. An inactivated viral vaccine (made of killed viruses) is currently available, but its effectiveness is suboptimal in children and the elderly, say the researchers.

"An alternative is vaccination with live attenuated viruses, which can be administered intranasally," say the researchers. "Such live vaccines induce an immune response which more closely mimics that raised after natural infection and theoretically should be more protective and longer lasting than that induced by injection of the killed vaccine."

(N.T. Parkin, P. Chiu, and K Coelingh. 1997. Genetically engineered live attenuated Influenza A virus vaccine candidates. Journal of Virology. 71:2772-2778.)

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ENGINEERING ON THE SURFACE

Researchers from Kyoto University, Japan; Japan's Women's University; and the Institute for Fundamental Research, Tokyo report that they have engineered the cell surface of the yeast Saccharomyces cerevisiae and given it the ability to use starch directly as its sole source of carbon.

The scientists believe this to be the first example of the application of cell surface engineering on a yeast to endow the cells with a new beneficial property. Their results appear in the April 1997 issue of the journal Applied and Environmental Microbiology.

S. cerevisiae is commonly used in the production of wine and bread. In addition, it is widely used in industrial production of protein and chemicals. It is considered safe for oral use and can be used in a variety of food and pharmaceutical products.

"Although starchy materials are available in abundance as carbon sources for cultivation, wild-type S. cerevisiae itself is unable to utilize starch," say the researchers. The new engineered version can. "This is the first example of an application of cell surface engineering to utilize and improve the metabolic ability of cells."

(T. Murai, M. Ueda, M. Yamamura, H. Atomi, Y. Shibasaki, N. Kamasawa, M. Osumi, T. Amachi, and A. Tanaka. 1997. Construction of a starch-utilizing yeast by cell surface engineering. Applied and Environmental Microbiology. 63: 1362-1366.)

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TO RECEIVE COPIES OF ANY OF THESE JOURNAL ARTICLES OR FOR MORE INFORMATION CONTACT:

Jim Sliwa (202) 942-9297 [email protected] **************************************************

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