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Tips from the Journals of the American Society for Microbiology

American Society for Microbiology

Bacteria prevent kidney stones

A single dose of bacteria could help alleviate a condition that is a common cause of kidney stones, say researchers from the United States and Britain. Their findings appear in the August 2002 issue of the journal Applied and Environmental Microbiology.

Hyperoxaluria is a condition in which there is too much of a compound called oxalate in the body. The excess oxalate combines with calcium inside the kidneys, forming kidney stones. The researchers have identified a bacterium, called Oxalobacter formigenes, that naturally exists in the digestive tract of most humans and breaks down oxalate. A single dose of the bacteria, when taken by volunteers lacking the microorganism in their digestive tract, resulted in colonization and an overall reduction of oxalate levels in urine.

"The present work suggests that intestinal oxalate degradation provides an ecological niche which O. formigenes may be uniquely fitted to occupy. Studies with colonized and noncolonized individuals of different ages and health status will advance our understanding of oxalate metabolism in the human gastrointestinal tract, and may ultimately provide practical approaches for the prevention or alleviation of hyperoxaluria," say the researchers.

(S.H. Duncan, A.J. Richardson, P. Kaul, R.P. Holmes, M.J. Allison and C.S. Stewart. 2002. Oxalobacter formigenes and its potential role in human health. Applied and Environmental Microbiology, 68: 3841-3847.)

UV light as an alternative to pasteurization

Ultraviolet light can kill potentially harmful microorganisms in apple cider and may be a feasible alternative to pasteurization say researchers in the August 2002 issue of the journal Applied and Environmental Microbiology.

In the study scientists contaminated fresh apple cider with the Cryptosporidium parvum parasite and then treated a portion of it with ultraviolet (UV) rays. They injected treated and non-treated samples into mice. The mice receiving treated cider remained healthy while those receiving non-treated cider died.

UV light may provide the cider industry with the solution it needs to keep its product safe without risking loss of original texture and flavor. "Cider-associated outbreaks of cryptosporidiosis have prompted the cider industry to search for a process that inactivates C. parvum oocysts without affecting the organoleptic qualities of fresh cider while being cost-effective for small cider mills," said researchers. "UV treatment of apple cider is a feasible technology for the reduction of viable C. parvum oocysts in fresh apple cider."

(D.E. Hanes, R.W. Worobo, P.A. Orlandi, D.H. Burr, M.D. Miliotis, M.G. Robl, J.W. Bier, M.J. Arrowood, J.J. Churey, and G.J. Jackson. 2002. Inactivation of Cryptosporidium Parvum Oocysts in Fresh Apple Cider by UV Irradiation. Applied and Environmental Microbiology, 68.8: 4168-4172.)

TB makes a run for the border

Drug-resistant tuberculosis does not stop at the U.S.-Mexico border, but can be found in clusters straddling it, say researchers from Texas. They report their findings in the August 2002 issue of the Journal of Clinical Microbiology.

In the epidemiological study, the researchers examined samples of Mycobacterium tuberculosis from over 900 patients in Texas and Mexico. They found that 20 strains, that were not only genetically identical but had identical drug-resistance patterns, could be found on both sides of the border.

"The results of this study indicate that drug-resistant M. tuberculosis isolates are transmitted between Mexico and the United States," say the researchers. "Control of drug-resistant tuberculosis in the United States therefore requires the control of tuberculosis in Mexico."

(T.N. Quitugua, B.J. Seaworth, S.E. Weis, J.P. Taylor, J.S. Gillette, I.I. Rosas, K.C. Jost, Jr., D.M. Magee and R.A. Cox. 2002. Transmission of drug-resistant tuberculosis in Texas and Mexico. Journal of Clinical Microbiology, 40: 2716-2724.)

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Full copies of all above articles can be accessed through the ASM website at http://www.asmusa.org/pcsrc/tip.htm .

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