Milk may help bacteria survive antibiotics

DUBLIN, Ireland (UPI) — Portuguese scientists say they’ve learned milk may help protect potentially dangerous bacteria from being killed by antibiotics used to treat animals.

The researchers from Portugal’s Technical University of Lisbon said bacteria sometimes form structures called biofilms that protect them against antibiotics and the body’s natural defenses. Now the scientists have discovered one of the most important micro-organisms that causes mastitis in cows and sheep, called staphylococcus, can evade the animal’s defenses by forming such biofilms.

Mastitis is an infection of the udder in cattle and sheep.

The researchers, led by Manuela Oliveira of the university’s veterinary medicine department, found that when the staphylococci produce a biofilm, that structure protects them against host defenses and antibiotic treatment, allowing the bacteria to persist in the udder.

The researchers said they also determined low concentrations of antibiotics such as penicillin, gentamicin and sulphamethoxazole, combined with trimethoprim, were less effective against staphylococcus when compared with the same experiment performed in the absence of milk.

The research was presented Monday at Dublin, Ireland’s Trinity College during the fall meeting of the Society for General Microbiology.

Copyright 2008 by United Press International

from Arcamax Science and technology e-zine, 09-10-2008

Old bacteria relied on arsenic, not water

WASHINGTON (UPI) — U.S. scientists say they have discovered ancient bacteria that relied on arsenic, rather than water, to grow during photosynthesis.

The discovery, which the scientists said likely dates to a few billion years ago, came in research funded by the National Aeronautics and Space Administration’s Exobiology Program and the U.S. Geological Survey.

The finding is said to add an important dimension to the arsenic cycle “and highlights a previously unsuspected process that may have been essential for establishing the arsenic cycle on the ancient Earth,” the USGS said. The arsenic cycle occurs when enzymes trigger microorganisms to convert inorganic arsenic to organic arsenicals.

The discovery came during a study of two small hot spring-fed ponds on the southeastern shore of Paoha Island in Mono Lake, Calif.

The research that included scientists from Duquesne University, the University of Georgia and Southern Illinois University appears in the journal Science.

Copyright 2008 by United Press International

from Arcamax Science and Technology e-zine, 08-21-2008