Superbugs – bacteria that do not respond to many of the drugs designed to treat them – are an increasing problem, particularly in hospitals. Now, a new study presented at a meeting in the US suggests if a patient develops an infection while staying in a hospital, the chances of that infection becoming drug-resistant increase with each extra day spent in the hospital.
Researchers at the Medical University of South Carolina (MUSC) analyzed historical data from their academic medical center of 949 cases of patients who had acquired gram-negative infections during hospitalization.
They found if a patient acquires a gram-negative infection while staying in the hospital, the chances of that infection being multidrug-resistant goes up by 1% for each day of hospitalization.
The team presented their findings at the 54th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) that is being held in Washington, DC, from September 5-9, 2014.
According to the US Centers for Disease Control and Prevention (CDC), gram-negative bacteria are a particular problem in acute health care – they cause wound or surgical site infections, pneumonia, blood infections, meningitis and other serious conditions. They are resistant to several drugs and are becoming increasingly resistant to most available antibiotics.
Gram-negative bacteria are able to adapt and find new ways to be drug-resistant; they can swap genetic material with each other, thus passing on drug-resistance to other bacteria.
Hospital-acquired infections are responsible for a large proportion of hospital-related deaths, and rates are rising, say the MUSC researchers.
On any given day, they note, about 1 in 25 patients in hospitals have at least one hospital-acquired infection, of which around 1 in 3 is caused by gram-negative bacteria.
But there is currently not enough information on how many infections and deaths are due to gram-negative bacteria. The CDC estimate that in the US in 2011, approximately 75,000 deaths occurred in around 722,000 patients with hospital-acquired infections. More than half of the deaths occurred outside of the intensive care unit.
In their study, the MUSC researchers found in the first few days of hospitalization, about 20% of infections are associated with multidrug-resistant gram-negative bacteria. This proportion rises steadily for the first 4 or 5 days, and then jumps dramatically to over 35% at 10 days.
Looking at the data statistically, the team suggests this means the risk of a gram-negative infection becoming drug-resistant during a hospital stay increases by about 1% for each day in the hospital.
John Bosso, one of the study authors and professor in pharmacy at MUSC, says:
“Our findings emphasize one of the risks of being in the hospital, acquiring a multidrug-resistant infection. At the very least, this observation argues against both unnecessary hospitalization and unnecessarily long hospitalization.”
He and his team also discovered that the chances of acquiring a drug-resistant infection in the hospital appears to vary from superbug to superbug. This information could be important for doctors and clinicians hoping to reduce rates of hospital-acquired infections, says Prof. Bosso.
Meanwhile, in June 2014, Medical News Today learned how a group of UK researchers discovered a possible way to stop drug resistance in bacteria. The team hopes the study, which explores how superbugs build their defenses, may lead to new drugs that the bacteria cannot become resistant to.