One in 25 patients in U.S. hospitals has an infection acquired as part of his or her care despite modest progress in controlling those pathogens inside medical facilities, the Centers for Disease Control and Prevention reported Wednesday in its most comprehensive look at a stubborn and lethal health-care problem.

The CDC’s 2011 survey of 183 hospitals showed that an estimated 648,000 patients nationwide suffered 721,000 infections, and 75,000 of them died, though it is impossible to tell from the data how many deaths were directly attributable to the acquired infection, said Michael Bell, deputy director of CDC’s division of health care quality promotion. Nevertheless, “today and every day, more than 200 Americans with healthcare-associated infections will die during their hospital stay,” CDC Director Tom Frieden said in a news release.

The most common infections are pneumonia (22 percent), surgical site infections (22 percent), gastrointestinal infections (17 percent), urinary tract infections (13 percent), and bloodstream infections (10 percent), the agency reported in the study, published Wednesday in the New England Journal of Medicine.

When coupled with the growing risks posed by of antibiotic resistant bacteria, the prevalence of hospital-acquired infections remains a serious problem for caregivers, one that the CDC is continuing to battle on a state-by-state and even hospital-by-hospital basis.

Atop the list of pathogens acquired in hospitals is the bacterium clostridium difficile (commonly know as c. diff), which can cause gastroenterological illnesses so severe that removal of a patient’s colon is sometimes required, Bell said. It was responsible for 12.1 percent of the infections turned up by the survey. Also common was methicillin-resistant staphylococcus aureus (MRSA), a staph infection that has become resistant to common antibiotics.

President Obama’s proposed fiscal 2015 budget includes money to battle antibiotic resistance. Bell said the continuing effort would require hospitals to remain judicious about the use of antibiotics in order to gradually lessen resistance to them, in the hope that some will become effective again. He said the problem of widespread resistance also is prompting new approaches to controlling bacteria.