The US Centers for Disease Control and Prevention said today that bloodstream infections caused by Staphylococcus aureus remain a significant and deadly problem in US hospitals, and that progress on reducing the most dangerous type of staph infection has stalled.
According to the agency's latest Vital Signs report, more than 119,000 people suffered from S aureus bloodstream infections in 2017, and nearly 20,000 died. In addition, the report found that while the rate of methicillin-resistant S aureus (MRSA) bloodstream infections in US hospitals fell by more than 17% annually from 2005 through 2012, the rates of decline has slowed since then.
The report also found that MRSA infections that originate in the community have been declining more slowly than hospital-onset cases, and community-onset methicillin-susceptible S aureus (MSSA) infections are on the rise.
"The bottom line is this: We have prevented many staph infections, but while we've made important progress, our data show that more needs to be done to stop all types of staph infections," CDC Principal Deputy Director Anne Schuchat, MD, said in a telebriefing.
Trends in hospital, community infections
The findings are based on data from the CDC's Emerging Infections Program (EIP), which conducts population-based surveillance for invasive MRSA in six states, and two large electronic health record (EHR) databases. CDC investigators analyzed the data from these sources to describe trends in the incidence of hospital-onset and community-onset MRSA bloodstream infections from 2005 through 2017 and to estimate the overall incidence of S aureus bloodstream infections and associated in-hospital mortality.
The EIP data showed that the incidence of hospital-onset and community-onset MRSA bloodstream infections overall fell by 74% and 40%, respectively, from 2005 through 2016. Hospital-onset MRSA bloodstream infection rates decreased by 17.1% a year from 2005 through 2012, but didn't significantly change from 2013 through 2016. Community-onset MRSA bloodstream infections, meanwhile, fell by 6.9% annually from 2005 through 2016.
That reduction was mainly driven by a drop in community-onset infections that were linked to a previous hospital stay.
The EHR data, which came from 447 hospitals, showed that hospital-onset MRSA bloodstream infection rates fell by 7.3% per year from 2012 through 2017, with no significant change in community-onset MRSA rates. Hospital-onset MSSA infection rates also saw no change, while community-onset MSSA increased by 3.9% each year.
The authors of the report suggest that the steady rate of community-onset MRSA infections, and the rise of community-onset MSSA infections, could be linked to the ongoing opioid epidemic, noting that emerging evidence suggests a 16-fold increased risk of invasive MRSA among people who inject drugs.
The in-hospital mortality among patients with staph bloodstream infections over the entire study period was 18%, with no significant change observed from 2012 through 2017. Overall, an estimated 119,247 cases of S aureus bloodstream infection, and 19,832 associated deaths, occurred in 2017.
Schuchat said the trends observed in the data were consistent with recent data from the National Healthcare Safety Network, which tracks healthcare-associated infections.
Adherence to reduction strategies waning
MRSA has long been a problem in healthcare settings because it easily spreads between infected patients and healthcare workers. If those healthcare workers don't clean their hands properly, they can spread MRSA to other patients. In addition, hospital patients who are colonized with MRSA can spread the bacteria to other patients by contaminating bed linens and bed rails, bathroom fixtures, medical equipment, and other parts of the hospital environment.
While MRSA commonly causes skin infections, some of which can be severe, it becomes significantly more life-threatening when it invades the bloodstream, especially in older patients and those with chronic conditions.
Hospitals have tried a number of different CDC-recommended approaches to rein in MRSA transmission, including more rigorous hand hygiene and environmental cleaning measures, use of contact precautions (requiring healthcare workers to wear gloves and gowns when caring for MRSA patients), improved antibiotic use, and better screening of patients for MRSA colonization. In addition, hospitals have done a better job of preventing MRSA infections tied to medical devices and procedures.
Schuchat said these strategies have helped drive the steep declines in hospital-onset MRSA infections seen in previous years and continue to help individual facilities decrease MRSA transmission. On a national level, however, hospitals appear to have reduced their use of contact precautions and may not be following CDC recommendations as closely.
"Inconsistent and declining adherence to these recommendations might also be slowing our progress," she said. "The plateau may be [because] hospitals and healthcare providers have tired of instituting the comprehensive recommendations."
Among the exceptions are Veterans Affairs (VA) medical centers, which Schuchat said provide an example of what can be achieved when hospitals adhere to MRSA reduction measures.
In another Vital Signs report published today, CDC researchers found that a MRSA prevention program implemented at all 153 VA medical centers reduced hospital-onset S aureus and MRSA infections by 43% and 66% from 2005 through 2017. The multifaceted intervention included, among other components, contact precautions and admission screening for nasal MRSA carriage.
Prioritizing prevention, reduced transmission
Schuchat said that while there is no one-size-fits-all approach, national trends indicate that healthcare providers and hospital administrators need to prioritize prevention of staph infections and implement the CDC recommendations (particularly contact precautions). They also need to continually review their data to determine when additional interventions are needed and find new ways to keep staph from spreading.
She also recommended that clinicians consider additional measures for high-risk patients, including those who are in intensive care units.
"Without both renewed commitment to current infection control practices and innovations that identify additional opportunities to reduce infections, staph will kill more people," she said. "We call on healthcare professionals to step up prevention efforts, and follow CDC guidelines to protect more patients from staph."
In a statement today, the Society for Healthcare Epidemiology of America (SHEA) said the report highlights the need to focus on evidence-based interventions to reduce MRSA transmission.
"For MRSA and MSSA, no single prevention approach works in all situations," SHEA President Hilary Babcock, MD, MPH, said.
"Combination, or bundled, interventions are usually the best approach. Which strategies will have the biggest impact may depend on the local context. SHEA urges expanded funding support for research into what interventions are most effective in what settings, so that infection prevention programs can continue to reduce these infections in patients across healthcare settings."
See also:
Mar 5 CDC Vital Signs report
Mar 5 CDC Vital Signs report on staph infections in VA medical centers
Mar 5 SHEA press release
