CHICAGO (Reuters) - While rates of drug-resistant staph infections appear to be on the rise in society in general, hospitals are making progress at curbing at least one source of infection in some of their sickest patients, US health officials said on Tuesday.

Rates of methicillin-resistant Staphylococcus aureus infections, known as MRSA, caused by tubes used to give drugs and fluids to intensive-care patients fell nearly 50 percent between 1997 and 2007, Dr. Deron Burton of the US Centers for Disease Control and Prevention found.

Drug-resistant bacteria are a growing problem in hospitals worldwide, marked by the rise of superbugs such as MRSA. Many experts believe poor hospital practices are to blame.

Burton and colleagues studied hospital data on blood infections caused by tubes inserted into veins known as central line catheters. They looked at data for both adult and pediatric intensive care units between 1997 and 2007.

They found 1,684 intensive care units reported a total of 33,587 blood infections caused central line catheters during the study period.

Of those, 2,498, or about seven percent, were drug-resistant strains of MRSA, and 1,590, or 4.7 percent, were staph infections that were susceptible to antibiotics, they reported in the Journal of the American Medical Association.

They said while the overall percentage of infections caused by MRSA increased, the actual number of MRSA cases fell by half during the study period, with steady declines in the infection rate reported from 2001 through 2007.

Burton and colleagues suspect hospitals are following CDC-recommended prevention guidelines, which may have contributed to the improvements.