Cases of Methicillin-resistant Staphylococcus aureus infections (MRSA) increased four-fold in California hospitals between 1999 and 2007 to 52,000 cases, according to a new state report, which also suggests the annual number of MRSA deaths are 3.2 times more than estimates for seasonal influenza.
The report was issued by the California Office of Statewide Health Planning and Development using hospital patient discharge data.
The largest increase in MRSA cases came in young to mid-range adult aged patients, who were admitted from home with infections of the skin.
The report said that by patient group, the biggest increase in resistant strains of the bacteria over that eight-year period was attributed to patients admitted to hospitals from prisons or jails, which saw a greater than 2000% increase. Also contributing to the rise was a 540% increase in newborns with resistant strains and a 120% increase in MRSA admissions from long-term care facilities.
Asked to comment on why these patient groups had higher rates of resistant strains, report author Mary Tran says, "These increasing rates could reflect increasing circulation of MRSA in the community, but we have no specific information to address this question."
While there was little change in patient characteristics for strains of the bacteria that are sensitive to antibiotic treatment, there was a marked shift in those with MRSA.
There was a 1,663% increase in the number of children with MRSA (from 188 to 3,315), a 556% increase in the number of adults between the ages of 18 to 64 (from 3,996 to 26,226), and a 143% increase in the number of seniors (from 9,320 to 22,678).
There was some good news in the report. The percentage of patients with MRSA who died within 30 days of arriving in the hospital decreased from 35% in 1999 to 24% in 2007 and the length of hospital stays for patients with MRSA declined from 21 days to 15 days in this period.
But the percent of patients with infection who resisted treatment with antibiotics increased from 30% to 60%. Nationally, MRSA cases increased from 45% to 60%.
The report noted that over the years, the resistant strain of bacteria has become more virulent and is more often found in healthy people, without pre-existing conditions, people who have not had any contact with a healthcare setting.
They manifest as pimples or boils, but can also cause more serious skin infections or infect surgical wounds, the bloodstream, the lungs or urinary tract.
Jan Emerson, spokeswoman for the California Hospital Association, said the report doesn't provide a lot of detail "other than the total of cases jumped between 1999 and 2007. Also it appears most of the cases came from community-acquired MRSA rather than hospital-acquired MRSA."
Jon Rosenberg, MD, of the California Department of Public Health's Infectious Disease Branch, says the OSHPD report is a reminder for hospital workers and other healthcare providers to be especially on their guard to use precautions when treating patients.
"We know that more and more we're seeing patients with this particularly nasty organism that we don't want spreading through the healthcare system," Rosenberg says. To this point, most of the strains of MRSA are being brought in from the community, not passed around within hospital settings, but that could change if providers aren't vigilant.
"You need to observe he highest levels of infection control," he says. "The thing that's different about this organism is the potential threat to the healthcare worker."