Drug-Resistant Bacteria Can Raise Sepsis Risk

Treating sepsis can be even more difficult if the bacteria responsible are resistant to antibiotics.

In some cases bacteria may be spreading from the bowel or urinary tract into the bloodstream, while in others the bacteria found in patients’ urine or stool samples could be transferring their ability to resist antibiotics to other bacteria in the body, which then can cause sepsis.

Scientists at the Karolinska Institutet studied 66,000 people and showed that the risk of drug resistant sepsis is highest soon after drug resistant bacteria have been detected in a patient’s urine or stool, and that this risk diminishes over time. They say their findings could help doctors diagnose drug resistant sepsis and inform treatment choices. The team studied all subjects who were found to have specific types of bacteria in their urine or stool samples in Sweden between 2007 and 2012, more than 22,000 in total. They compared them with an equivalent group of 44,000 people who had no diagnosis of extended-spectrum β-lactamase-producing Enterobacteriaceae (EPE).

The investigators focused on certain bacteria, such as Escherichia coli, that produce enzymes called extended spectrum β-lactamases. These enzymes allow bacteria to break down a variety of antibiotics including penicillin and third-generation cephalosporins. They followed the subjects for six years to find out if they subsequently developed a bloodstream infection. The data revealed that people whose bowels had been colonized previously by EPE were 57 times more likely to develop an EPE infection of the bloodstream, compared to the general population. For those with a previous finding of EPE in their urine, the risk was 113 times higher than the general population. Over the six-year study period, 2% of those with EPE in the bowel and 4% of those with a urinary tract infection went on to have a bloodstream infection with EPE. This compares to 0.02% in the general population.

Joakim Isendahl, MD, who presented the study said, “Knowing if a patient has had a previous finding of EPE, and how long ago it was, helps inform doctors on when last-­resort drugs are essential, but also on when they are not needed. This is important since prudent use is imperative to keep them effective. We found that the riskiest time was in the days and weeks after the bacteria were found in the urine or stool sample, but there is still an increased risk up to three years later.” The study was presented at the 27th European Congress of Clinical Microbiology and Infectious Diseases, held April 22-25, 2017, in Vienna, Austria.