‘Superbug’ origins: Key to stop hospital-acquired infections

Methicillin-resistant Staphylococcus aureus (MRSA) infections are a leading cause of extended hospitalizations and escalating health care costs. But where do these infections originate? A new study by a Texas A&M Health Science Center infectious disease expert is bringing researchers one step closer to solving a great mystery surrounding the so-called “superbugs.”

Caused by a type of staph bacteria that’s become resistant to many of the antibiotics used to treat ordinary staph infections, most MRSA cases occur in people who have been in hospitals or other health care settings, like nursing homes. Coined a “superbug,” MRSA is one of the four most dangerous bacteria, according to the Centers for Disease Control and Prevention.

A typical 100-bed hospital sees, on average, 10-20 hospital-acquired infections per year. In additional to the human toll, hospitals now have a financial reason to reduce hospital-acquired infections: beginning in 2017, the federal government will dramatically reduce Medicare payments to hospitals that exceed incidences of certain conditions, such as hospital-acquired infections.

“In order to stop the spread of MRSA in our hospitals, we need to pinpoint where the infection originated in patients who were hospitalized,” said Chetan Jinadatha, M.D., M.P.H., assistant professor at the Texas A&M College of Medicine and chief of infectious diseases at the Central Texas Veterans Health Care System in Temple.

A prevalent region MRSA is found on our body is in our nares (the external openings of the nasal cavity) – more commonly known as nostrils. Jinadatha’s study focused on identifying if these MRSA colonizations in our nares are contributing to the rising amount of MRSA cases in health care settings. Interestingly, they found this is not the case.

“Our study found that most MRSA infections are actually not due to the colonies living in our nares,” he said. “Among 50 of our patients, 36 did not acquire the bacteria from this region.” In other words, 74 percent of acquired MRSA are from a non-nasal source.

MRSA also lives on other body regions like the groin and it is possible that colonies from different areas will move to the bloodstream and result in an infection. However, the impact of different MRSA colonizations is still largely unknown.

Jinadatha said MRSA patients may have been exposed to the bacteria during a hospital stay. “MRSA is resilient and can survive on surfaces for long periods of time. Hands can be easily contaminated. If health care workers are not implementing good hygiene practices, then MRSA can be spread from worker to patient.”

“In order to stop the spread of MRSA in our hospitals, we need to pinpoint where the infection originated in patients who were hospitalized.”

The topic of hospital-acquired infection control is not new for Jinadatha. Previous research out of his lab looked at the effectiveness of a germ-zapping robot to help clean hospital rooms, which could hold the key to preventing the spread of superbugs—and in turn, save countless dollars and, most importantly, lives. The study, published in the American Journal of Infection Control, found that in just 12 minutes, a UV light robot cut the amount of bacteria in the room by about 70 percent–roughly the same level of effectiveness as manual disinfection. Interestingly, manual disinfection plus UV light killed 99 percent of the bacteria that cause MRSA.

The recent study—published in the American Journal of Infection Control—is only the beginning for Jinadatha. “We want to expand on our initial findings and dig deeper into the other sources for MRSA colonization,” he said. “We know the environment plays a huge role and future findings will stress how hospitals can remove these strains from the infection cycle.”