When it comes to drug-resistant "superbugs," there’s some good news — and some not-so-good news. On the positive side, scientists have created a new test that can quickly and cost-effectively detect the superbug carbapenem-resistant Enterobacteriaceae (CRE). But other new research shows that each day a patient is in the hospital, their risk of getting a multidrug-resistant infection goes up.
The Carba NP test is based on the original tool for diagnosing CRE, created by researchers in France and Switzerland. Those researchers came up with a DNA-based test, which is known as the polymerase chain reaction, or PCR, test. That test is not only costly, but it also requires specialized equipment.
Carba NP, on the other hand, will allow more facilities to afford to run the test. Plus, it can detect CRE in just 2.5 hours.
Test Results in Hours, Not Days
In the study, author Karim Morey of the Oregon State Public Health Lab looked at how well the Carba NP test identified 59 of 201 samples as producers of CRE. The scientists first identified 92 percent of the CRE producers. With further tweaking, they reached 100 percent sensitivity and completed the test in an average of 2.5 hours.
Dr. Ronald Nahass, a physician with ID Care, an infectious disease practice based in Hillsborough, New Jersey, said the existing PCR test takes two to three days. Being able to receive results in hours will be an advantage for patients and doctors.
Nahass noted that other superbugs can be diagnosed rapidly, which he said, is "a big deal for us."
"You're able to give [patients] directed therapy quicker," Nahass said. "Any time you can bring a test that identifies one of these superbugs, which gets us to a point of rapid diagnosis ... that's a good thing."
Experts Give the Test Thumbs Up
Dr. Matthew D. Sims, who heads infectious disease research at William Beaumont Hospital in Royal Oak, Michigan, thinks the test will be a welcome improvement. “Having a low-cost, highly sensitive, and specific test to rapidly diagnose CRE would be of significant benefit, allowing us to get patients on the right antibiotics faster and prevent inappropriate antibiotic use,” he said.
Dr. Mildred Frantz, a physician practicing in Eatontown, New Jersey, is excited about the upgraded test. “Rapid identification of drug resistant bacteria will change the course of treatment, alleviating the use of wide spectrum antibiotics that may not work, and specifically targeting the correct bacteria,” she said. “This can save lives and protect against the spread of this dangerous bacteria.”
The test creators also found a way to detect extended-spectrum beta-lactamase (ESBL), another antibiotic-resistant bacteria, in urine samples. This test costs less to perform and can be done nearly anywhere. Compared to current tests, which take one or two days, this test takes only 20 minutes.
The Longer Patients Are Hospitalized, the Greater the Risk
Research presented at the 54th Interscience Conference on Antimicrobial Agents and Chemotherapy found that for a patient who contracts an infection during a hospital stay, the risk of the infection becoming multidrug-resistant increases by 1 percent for each day spent in the hospital.
Medical University of South Carolina researchers evaluated data from 949 cases of Gram-negative infections. They found that the percentage of those types of infections within a few days of hospitalization was about 20 percent, which increased for four or five days. At 10 days, it went up significantly, to more than 35 percent.
A statistical analysis showed a 1 percent jump in risk for every day of hospitalization.
Gram-Negative Infections on the Rise
Gram-negative bacteria cause infections including pneumonia, bloodstream infections, wound or surgical site infections, and meningitis in healthcare settings. Gram-negative bacteria are resistant to multiple drugs and to most available antibiotics. These bacteria have built-in abilities to find new ways around antibiotics and can pass along genetic materials that allow other bacteria to become drug-resistant as well.
According to a European study, Gram-negative infections make up about two-thirds of the 25,000 annual deaths from hospital-acquired infections. The Centers for Disease Control and Prevention estimated in 2011 that there were about 722,000 hospital-acquired infections, which caused approximately 75,000 deaths.
“Our findings emphasize one of the risks of being in the hospital — acquiring a multidrug-resistant infection" said John A. Bosso, Pharm.D., a professor at the College of Pharmacy at the Medical University of South Carolina, and author of the research paper. "At the very least, this observation argues against both unnecessary hospitalization and unnecessarily long hospitalization."