No one who goes to the hospital expects to acquire a drug-resistant infection during his or her stay. However, such infections do occur. In 2007, a study performed by the Centers for Disease Control and Prevention demonstrated that methicillin-resistant Staphylococcus aureus (MRSA) caused more than 94,000 life–threatening infections and nearly 19,000 deaths in the United States during 2005. The study, published in the Journal of the American Medical Association, found that approximately 85% of all invasive MRSA infections were associated with health care settings.

At the CDC, efforts have been underway to better understand MRSA infections and which health care setting interventions work best to prevent these types of infections. Such efforts are critical because of the life-threatening impact these infections can have on patients such as bloodstream infections, surgical site infections, or pneumonia. “Staphylococcus aureus, which is the type of germ that is in MRSA, has been one of the most important pathogens causing healthcare-associated infections,” according to Centers for Disease Control Prevention (CDC) medical epidemiologist John Jernigan, MD.

MRSA In Health Care Settings

MRSA infections can occur through direct contact with people or surfaces that carry the bacteria. The staph bacteria can enter abrasions and skin cuts, and then spread. The main mode of transmission of MRSA from patient to patient in healthcare settings is through human hands, especially healthcare workers’ hands, according to the CDC.

Patients who undergo invasive medical procedures or who have weakened immune systems and are being treated in hospitals and health care facilities, such as nursing homes and dialysis centers, tend to be most susceptible to these infections. “Patients who are sick and undergoing invasive treatments, and who may be immunocompromised, are also more susceptible to infections from all germs, but in particular drug resistant germs,” Dr. Jernigan said.

MRSA infections have grown in healthcare settings over the years in part because of their ability to develop a resistance to antibiotics. When antibiotics are overused or inappropriately used, antibiotic resistance can occur and treatment becomes more difficult. “Antibiotic use is common in the setting in the care of patients in hospitals, and needs to be, and much of that use is absolutely appropriate,” Dr. Jernigan said. “However, it does select for and contribute to the transmission of these drug resistant germs.”

Prevention

Dr. Jernigan said that one of the ways in which CDC is assisting healthcare providers to prevent the spread of MRSA is through guidelines it provides. “We partner with our federal advisory committee known as the Healthcare Infection Control Practices Advisory Committee (HICPAC) and write guidelines based upon the best evidence available to help guide hospitals on what to do to prevent these and other types of infection,” Dr. Jernigan said.

Guidelines called Management of Multidrug-Resistant Organisms in Healthcare Settings, 2006, are designed to help guide healthcare providers in managing infections like MRSA. Those guidelines state “prevention of antimicrobial resistance depends on appropriate clinical practices that should be incorporated into all routine patient care. These include optimal management of vascular and urinary catheters, prevention of lower respiratory tract infection in intubated patients, accurate diagnosis of infectious etiologies, and judicious antimicrobial selection and utilization.”

“We at CDC recommend a multifaceted approach, which would include optimizing antimicrobial use, making sure you are following all of the recommendations for preventing device and procedure associated infections, and then finally, making sure that you are doing everything you can to prevent transmission of the organism from patient to patient in a healthcare setting,” Dr. Jernigan explained. “That latter part does involve greater attention to things like hygiene, simple infection control precautions etc, but we think all three of those approaches together will likely have the greatest impact.”

Prevention of MRSA and other healthcare associated infections is challenging in the healthcare setting because it is dependent on everyone who comes in contact with the patients adhering to infection control practices. “Your infection control program is only as strong as the weakest link in that chain, so to be successful, you need to have everyone internalize and recognize the importance of these practices in the change of behavior,” Dr. Jernigan said. “This in a setting that is very, very busy, and there are lots of other things that they are required to do correctly that have nothing to do with infections. So taking care of patients and coordinating the behavior of the 1,000 people who interact with those patients is a complicated thing, not to say that it can’t be done, but history has shown that it has been difficult to get adherence to infection control practices at the level that we would like to see.”

CDC is currently conducting research on how best to help hospitals and healthcare providers adhere to current infection control guidelines. “Changing the behaviors of large numbers of frontline healthcare facilities is not an easy thing to do. So, novel approaches to change the culture in the workplace so healthcare workers are consistently and reliably implementing these infection control precautions is an area that is of great interest,” Dr. Jernigan said.

In addition, Dr. Jernigan said that CDC is interested in better understanding the measured benefit of each of the recommendations it makes in preventing MRSA. Currently, their impact is unknown. “We recommend a multifaceted approach in guidelines, and it is very difficult sometimes to know what the incremental benefit of each of the recommendations or approaches is. We need more information on that among these many different things that we do…which ones give us the biggest bang for the buck if you will,” he said.

Hospital Surveillance

One tool that was developed to help hospitals and CDC with surveillance of healthcare-associated infection is the National Healthcare Safety Network (NHSN), which is an internet-based surveillance system that health care facilities can opt to participate in. Through the system, CDC is able to collect data from hospitals on the incidence of healthcare-associated infection in their facilities, and about their adherence to practices known to be associated with prevention of these infections. With the information collected through the system, CDC can do many tasks, including analyzing data to recognize any trends.

Hospitals that opt to participate in the system can use it to help them develop surveillance and analysis methods of healthcare-associated infections that help them develop interventions. The system also allows healthcare facilities that participate to share data between facilities and public health agencies. “We think that our surveillance system can be helpful to hospitals,” Dr. Jernigan said. “It is basically available to any hospital in the country that would like to participate. It formalizes a standard way of measuring infection rates so all the participants are measuring things in the same way. It gives hospitals an opportunity to not only track their own performance over time, but to confidentially compare their own performance to the average performance of all the other hospitals that are participating in the country. Hospitals can use this information to know how they are doing, to know whether they need to improve their programs and parts of the system can actually help them know where to focus their prevention efforts.”