Researchers from the University of Washington, Seattle and the University of Alaska Fairbanks have found bacterial activity in arctic wintertime sea ice and may attribute its survival to particle or surface attachment. Their findings appear in the January 2004 issue of the journal Applied and Environmental Microbiology.
Previous studies pertaining to bacterial activity in sea ice have been conducted during the "warm" sunlit season with results drawn from melted ice. In this study, samples of arctic sea ice were collected from Alaska during winter months and maintained at subzero temperatures while being tested for bacterial activity of Cytophaga-Flavobacteria-Bacteriodes (CFB) and Archea. Researchers found the existence of CFB and Archea in wintertime sea ice to be largely associated with attachment to surface particles, with the percentage of attachment increasing as temperatures decreased.
"We have identified in this study one possible strategy for continued bacterial activity in wintertime sea ice: association with particles or surfaces," say the researchers. "The observation of active bacteria at -20 degrees celcius suggests that wintertime sea ice is more than a refugium for temporarily preserved life and brings the discussion of limits of life on Earth to a different level."
(K. Junge, H. Eicken, J.W. Deming. 2004. Bacterial activity at -2 to -20 in arctic wintertime sea ice, 70. 1: 550-557.)
NEW TEST OFFERS FASTER DETECTION OF CONTAMINATED OYSTERS
Researchers from the University of Alabama at Birmingham have developed a new DNA-based test that allows for rapid detection of contaminated oysters. Their findings appear in the January 2004 issue of the journal Applied and Environmental Microbiology.
One of the leading causes of seafood-related illnesses in the United States, Vibrio vulnificus, is transmitted by consuming raw or poorly cooked oysters. Infection by V. vulnificus can result in gastroenteritis, septicemia and in many cases death. Due to the extreme number of illnesses reported, the Interstate Shellfish Sanitation Conference has intervened requesting that the number of shellfish-related illnesses be reduced by 60 % by the year 2007.
"In the last two years alone, California has experienced sixteen illnesses resulting in ten deaths, despite educational efforts directed at high-risk populations to warn them of the potential hazards of eating raw oysters."
The new test uses polymerase chain reaction (PCR) to test for the presence of V. vulnificus in as little as eight hours. Current methods require up to three days to confirm contamination.
"Rapid and sensitive detection of V. vulnificus would ensure a steady supply of postharvest treated oysters to consumers, which should help decrease the number of illnesses or outbreaks caused by this pathogen."
(G. Panicker, M.L. Myers, A.K. Bej. 2004. Rapid detection of Vibrio vulnificus in shellfish and Gulf of Mexico water by real-time PCR, 70. 1: 498-507.)
PET SNAKES MAY BE SOURCE OF SALMONELLA
German researchers have determined that exotic reptiles maintained as pets may be responsible for an increase in Salmonella cases in humans. Their findings appear in the January 2004 issue of the journal Applied and Environmental Microbiology.
"Children under the age of 10 years and immunocompromised people seem to be especially prone to infections with reptile-associated Salmonella spp. and often experience severe clinical courses, including fatalities due to septicemia and meningitis."
In the study, fecal samples were collected from pet snakes and tested for the presence of Salmonella. Strains of Salmonella enterica appeared in eighty-one percent of the samples. Although it is unclear how these snakes are infected with the bacteria, researchers believe it is through contact with contaminated feces.
"Our results indicate that very high percentages of snakes are colonized with Salmonella spp.," say the researchers. "To avoid transmission, strict hygienic precautions should be applied when reptiles are handled."
(M. Schroter, P. Roggentin, J. Hofmann, A. Speicher, R. Laufs, D. Mack. 2004. Pet snakes as a reservoir for Salmonella enterica subsp. diarizonae (serogoup IIIb): a prospective study, 70. 1: 613-615.)