Half of all patients in intensive care units around the world have infections, and more than 70 percent are being given antibiotics — a trend that could help more drug-resistant superbugs emerge, researchers reported on Tuesday.

Patients who had infections were more likely to die, especially of bloodborne infections known as sepsis, the survey of more than 13,000 patients found. They also spent more time in the ICU at greater expense to hospitals and patients.

But one of the biggest concerns was the widespread use of antibiotics in patients who were not infected — a practice that has been shown to lead to antibiotic resistance, when germs defy common drugs.

"Importantly, the incidence of sepsis is increasing, as is the number of consequent infection-related deaths," Dr. Jean-Louis Vincent of Erasme University Hospital in Brussels, Belgium and colleagues wrote in the Journal of the American Medical Association.

For the study, Vincent's team surveyed 13,796 adults in 1,300 intensive care units in 75 countries on one day — May 8, 2007.

The analysis took some time and revealed that 51 percent of the patients had infections and 71 percent were receiving antibiotics, either as treatment or to prevent infection.

In 64 percent of cases, the lungs were infected, and infections of the abdomen and bloodstream were also common.

The most common bacteria was Staphylococcus aureus, but E. coli and a family of bacteria called Pseudomonas were also common.

"Infection and related sepsis are the leading cause of death in noncardiac ICUs, with mortality rates that reach 60 percent and account for approximately 40 percent of total ICU expenditures," the researchers wrote.

TROUBLING TRENDS

Dr. Steven Opal of Brown University in Rhode Island and Dr. Thierry Calandra of Vaudois Hospital Center in Lausanne, Switzerland, who were not involved in the study, saw several troubling trends.

For instance, a type of bacteria known as gram-negative now account for 63 percent of infections. "This is not a favorable trend, because resistance among gram-negative bacteria is increasing and the number of therapeutic alternatives to treat these infections is diminishing," they wrote in a commentary.

The heavy use of antibiotics in ICUs can make such units into epicenters for bacteria to mutate into drug-resistant forms and to spread, they added.

But critical care doctors have little choice, they noted.

"Early intervention with appropriate antibiotics is lifesaving in patients with severe infection, yet the profligate use of antimicrobial agents contributes to progressive antimicrobial resistance," they wrote.

Doctors are penalized if they fail to treat with an antibiotic, but little happens if they over-treat patients.

And few good tests are available to tell if a patient is really infected or just carrying a germ. "With few alternatives available, it is understandable why intensivists opt for liberal antibiotic use and rely heavily on these therapeutic agents to carry patients through critical illness to recovery," Opal and Calandra wrote.

Without some "radical" new technology, such as vaccines or immunotherapy, there is little hope for the situation to improve, they added.