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Tips from the Journals of the American Society for Microbiology

American Society for Microbiology

VIRAL GENOMES IN MINERAL WATER MAY NOT CAUSE INFECTIONS IN HUMANS

Viral genomes found in mineral water may not indicate risk of humans contracting infectious viruses say French researchers. Their findings appear in the July 2003 issue of the journal Applied and Environmental Microbiology.

In the study, behavior patterns of Poliovirus 1, Norovirus and Feline calicivirus f9 were monitored when strains of each were submerged in mineral water ranging in temperature. Results showed that warmer temperatures had a significant impact on infectious viruses, while temperature in general had little effect on corresponding genomes. Additionally, the researchers found that infectious particles were more likely to diminish at a faster rate than viral genomes at all temperatures tested in this study.

"Thus, we concluded that a positive test for a viral genome in mineral water must be interpreted with utmost caution because of the lack of a correlation between the presence of viral genomes and viral infectivity," say the researchers. "Detection of viral genomes may be necessary to identify infectious risk for the human population, but it cannot be considered sufficient."

(B. Gassilloud, L. Schwartzbrod, C. Gantzer. 2003. Presence of viral genomes in mineral water: a sufficient condition to assume infectious risk? Applied and Environmental Microbiology, 69. 7: 3965-3969.)

BACTERIA MAY CAUSE CROHN'S DISEASE

The bacterium Mycobacterium avium subsp. paratuberculosis may be the cause of Crohn's disease say researchers from St. George's Hospital Medical School in London and the Centre for Ecology and Hydrology in the United Kingdom. Their findings appear in the July 2003 issue of the Journal of Clinical Microbiology.

Crohn's disease (CD) is an inflammatory bowel disease causing chronic inflammation in the intestines. Using a newly developed test for the bacterium, researcherstested intestinal mucosal biospy specimens extracted from humans with and without CD. Results showed the bacterium in 34 out of 37 patients with CD and in 9 of 34 patients without.

"The principal property which distinguishes M. avium subsp. paratuberculosis from all other candidate organisms in the causation of CD is the specific ability of M. avium subsp. paratuberculosis to cause chronic inflammation of the intestine of a broad range of histopathological types in many species of animals, including primates," say the researchers. "Its presence in the overwhelming majority of individuals with chronic inflammation of the intestine of the CD type inevitably suggests causality."

(T. J. Bull, E. J. McMinn, K. Sidi-Boumedine, A. Skull, D. Durkin, P. Neild, G. Rhodes, R. Pickup, J. Hermon-Taylor. 2003. Detection and verification of Mycobacterium avium subsp. paratuberculosis in fresh ileocolonic mucosal biopsy specimens from individuals with and without crohn's disease. Journal of Clinical Microbiology, 41. 7: 2915-2923.)

PLASTERBOARD COMPOSITION MAY EFFECT MOLD GROWTH

Researchers from Finland found that the composition of the core material of plasterboard, a commonly used building material, can alter the growth sporulation of harmful molds in the plasterboard. Their results appear in the July 2003 issue of the journal Applied and Environmental Microbiology.

In the study, the mold Stachybotrys chartarum, known to cause adverse health effects in humans, was grown on plasterboards of various compositions in saturated humidity to determine which components affect mold growth. They found that growth and sporulation decreased when the liner was treated with biocide, starch was removed from the plasterboard, or desulfurization gypsum was used in the core.

"This study shows that the growth of a strain of S. chartarum on plasterboard and the subsequent bioactivity of spores were affected by minor changes to the composition of the core or liners, but it could not be totally prevented without resorting to the use of biocides," say the researchers. "However, incomplete prevention of microbial growth by biocides even increases the cytotoxic potential of the spores."

(T. Murtoniemi, A. Nevalainen, M.R. Hirvonen. 2003. Effect of plasterboard composition on Stachybotrys chartarum growth and biological activity of spores. Applied and Environmental Microbiology, 69. 7: 3751-3757.)

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