Increasing numbers of hospitalizations in the state have been linked to infections from a spore-forming pathogen known as C. diff, according to a new report by the Pennsylvania Health Care Cost Containment Council.

Hospitalization rates were particularly high in southwestern Pennsylvania, according to the report, released today.

Statewide, 20,941 hospitalizations of patients with Clostridium difficile-associated disease occurred in 2005, up from 7,026 in 1995. The totals reflect infections acquired in hospitals and other settings.

Hospitalization rates for the disease increased by 173 percent, from 4.4 cases per 1,000 hospitalizations in 1995 to 12 per 1,000 in 2005. In southwestern Pennsylvania, the 2005 rate was 15.8, the highest of any region.

The mortality rate also rose statewide, from 5.8 percent in 1995 to 8.7 percent in 2005. That year, patients with C. diff-associated disease were four times as likely to die as patients without the disease.

Patients with the disease had hospital stays averaging 11.4 days in 2005, compared with 4.7 days for patients without the disease. People 65 and older were most likely to be hospitalized.

The significant increases in hospitalizations and mortality rates are "a growing public health concern," said Marc Volavka, the council's executive director.

Carolyn Scanlan, president of the Hospital & Healthsystem Association of Pennsylvania, said hospitals in more than 20 states are facing increased rates of C. diff.

She said health care providers, patients, and family members need to be aware of symptoms, the need for early diagnosis and treatment, and techniques for prevention.

The problem appears to be due to a new, more virulent strain of C. diff that is more easily transmitted, said Dr. Carlene Muto, director of infection control at the University of Pittsburgh Medical Center.

"We can certainly say that C. diff disease has increased nationally and internationally," she said. "It's making patients much sicker than we've known in the past."

Many cases involve people who have had recent treatment with antibiotics, which can affect bacteria normally living in the intestine and allow C. diff to multiply. The disease can be spread by health care workers who have contact with infected patients or by touching surfaces contaminated with C. diff spores.

The disease caused by C. diff infection can range from mild cases of diarrhea to more severe conditions like colitis, bloodstream infections or death.

Mr. Volavka said the council decided to investigate C. diff cases because of problems reported outside Pennsylvania and because of its concerns about the costly, often life-threatening infections that patients can acquire in hospitals. In November, the council released a groundbreaking report, believed to be the first of its kind in the nation, that provided details about hospital-acquired infections.

Prescription for Pennsylvania, Gov. Ed Rendell's plan to cut costs and improve the quality and availability of affordable health care, includes measures aimed at reducing infections acquired in health care facilities.

Mr. Volavka said that in the future, hospitals will be asked to report whether their hospital-acquired infections are due to C. diff or to another pathogen, methicillin-resistant staphylococcus aureus, known as MRSA.

Mr. Volavka said he did not know why hospitalization rates for C. diff disease were higher in southwestern Pennsylvania. He said the higher rates were not due to differences in patients' age or sex.

Dr. Muto said differences in testing could account for some of the disparity. In some facilities, more sophisticated testing, for example, could lead to identifying more cases, she said.

After rates of hospital-acquired C. diff disease rose significantly in 2000 at UPMC Presbyterian, officials instituted specific measures to control the disease, Dr. Muto said.

Those measures have included using bleach to clean the rooms of patients infected with C. diff, because the usual hospital disinfectant doesn't kill spores produced by the organism, she said. Another emphasis has been hand washing with soap and water, which is more effective against C. diff than alcohol-based hand disinfectants.

Rates for the disease have since dropped sharply at UPMC Presbyterian, she said, and the cleaning measures also are used at other UPMC hospitals.