News in brief - Feb. 6, 2006

Antibiotic resistance study looks at soil bacteria - Saltwater therapy improves lung function for cystic fibrosis patients - Continuous therapy better at keeping HIV in check - Genetic risk factor for type 2 diabetes discovered

Antibiotic resistance study looks at soil bacteria

Studying bacteria that live in dirt could prove to be useful in identifying how and why antibiotic resistance happens in the bacteria that infect people, according to research in the Jan. 20 Science.

Researchers found that the numerous ways soil-dwelling bacteria become resistant to antibiotics are identical to resistance patterns seen in patients. Soil-dwelling bacteria also play a central role in treatment of infectious diseases. Approximately two-thirds of all antibiotics are produced by bacteria called actinomycetes, commonly found in soils, compost and other environmental sources.

Researchers from McMaster University in Ontario screened 480 strains of soil bacteria isolated from diverse locations for resistance to 21 clinically relevant antibiotics. At high drug concentrations, the soil-dwelling bacteria displayed a stunning level of resistance, said the researchers. Not only were the bacteria resistant to an average of seven to eight antibiotics, but every strain was found to be multidrug-resistant.

"This work could prove to be extremely valuable to the drug development process, complementing traditional laboratory studies of clinical situations," said Dr. Gerry Wright, chair of biochemistry and biomedical sciences at McMaster's Michael G. DeGroote School of Medicine.

Saltwater therapy improves lung function for cystic fibrosis patients

Two teams of medical scientists have identified what they believe is a simple, effective and inexpensive treatment to reduce lung problems associated with cystic fibrosis. The new therapy also appears to be safe and easy to take.

By inhaling a saltwater aerosol solution almost twice as salty as the Atlantic Ocean for between 10 and 15 minutes at least twice a day, young patients should be able to avoid a significant part of the damage the disease causes to their lungs, the researchers said.

Reports on both studies, which were collaborative and complementary, appeared in the Jan. 19 New England Journal of Medicine.

Cystic fibrosis appears on average in one of four children of parents who both carry a defective copy of a gene known as CFTR. The children soon develop chronic lung damage, since their lungs cannot clear excessive sticky mucus by sweeping it into the mouth, where it is swallowed and eliminated.

The study appears to establish the concept that the surface of the lungs of CF patients are dehydrated, and restoring hydration with hypertonic saline treats the basic cause of this disease. The salt sucks water from the lung tissue out onto the airways.

One branch of the study conducted at the University of North Carolina involved 24 patients treated with the high-salt solution for two-week periods and the second study, conducted in Australia, studied 164 patients for almost a year.

Continuous therapy better at keeping HIV in check

The National Institute of Allergy and Infectious Diseases halted enrollment in the Strategies for the Management of Anti-Retroviral Therapy trial in January because early data indicated overwhelmingly that taking HIV medications without interruption was far safer than the alternative.

This large international trial, involving 33 countries and 6,000 participants, was established to determine the best course of treatment for those infected with HIV. After 15 months, those randomized to receive "episodic therapy" -- taking medication when CD4+ counts dropped below a certain level -- had twice the risk of death and of developing full-blown AIDS as well as an increased incidence of cardiovascular, kidney and liver disease.

"The SMART trial reached a conclusion much earlier than we expected," said James Neaton, PhD, the study's chief statistician and a professor at the University of Minnesota in Minneapolis.

"That is the significant value and potential power of conducting such a large trial."

The study was launched to definitively answer whether treatment interruptions, considered a possible option to reduce the significant cost and side effects associated with antiretroviral therapy, actually could lead to better outcomes. Researchers intend to continue to follow participants.

Genetic risk factor for type 2 diabetes discovered

A polymorphism in the gene that plays a role in stabilizing levels of blood glucose has a strong link to the development of type 2 diabetes, according to a letter published online Jan. 15 in Nature Genetics. It will appear in print in the February issue.

Researchers with Decode Genetics who are studying the people of Iceland found that the "transcription factor 7-like 2" gene (TCF7L2) on chromosome 10 increased the risk of type 2 diabetes by 45% in those who have one copy of this gene. Those who are homozygous have a risk increased by 141% in comparison to those who do not have this gene at all. About 38% of people carry at least one copy of the gene with only 7% carrying two.

This gene is believed to play a significant role in about 20% of cases of type 2 diabetes, and researchers replicated this finding in Danish and American cohorts.

Authors suggest that this finding will open the door to genetically targeted therapies that prevent and treat this disease.

"This is a milestone in human genetics," said Dr. Kari Stefansson, senior author on the paper and Decode CEO. "This is also an exciting starting point for the discovery of new drugs."