On the watch for antibiotic-resistant mycoplasma pneumoniae

Ken Waites, M.D., professor of pathology and director of the UAB Diagnostic Mycoplasma Laboratory, will lead one of those infectious disease sentinels with the help of a one-year, $512,000 contract from the United States Centers for Disease Control and Prevention, or CDC. Waites and colleagues in the UAB departments of Medicine and Pediatrics are setting up sentinel surveillance for Mycoplasma pneumoniae infections at eight medical centers across the United States.

M. pneumoniae is an important cause of respiratory tract infections in children and adults that can range in severity from mild to life-threatening. During the epidemics that occur every few years, M. pneumoniae causes about 20 to 40 percent of community-acquired pneumonias seen in the general population, and 70 percent seen in closed populations such as college dormitories, military barracks and nursing homes.

Around the world, M. pneumoniae pathogens have started to show resistance to the macrolide antibiotics, such as erythromycin and azithromycin, that are commonly used to treat patients with respiratory infections. This resistance can complicate treatment. Little is known about the amount of macrolide resistance among M. pneumoniae infections in the United States, whether that amount of resistance is increasing, and whether infections with macrolide-resistant M. pneumoniae have worse clinical outcomes than infections with macrolide-susceptible M. pneumoniae.

Waites and colleagues will set up surveillance at Children's of Alabama in Birmingham; Lurie Children's Memorial Medical Center, Chicago; Memorial Sloan Kettering Cancer Center, New York City; Seattle Children's Hospital; Children's Mercy Hospital, Kansas City, Missouri; Hackensack University Medical Center, Hackensack, New Jersey; the University of Texas Health Science Center, San Antonio; and Children's Hospital Los Angeles.

The first six sites were part of the first multicenter surveillance data on macrolide-resistant M. pneumoniae in the United States during 2012-14. That surveillance found 13.2 percent of M. pneumoniae isolates were resistant to macrolide antibiotics.

The new sentinel surveillance program will provide the first U.S. data that also includes clinical information about symptoms of patients and disease severity. Clinical samples that will be evaluated were collected and frozen in 2015-17, with additional samples to be collected during the upcoming year. Thus, the surveillance will cover four years of infections.

Clinical specimens submitted by participating medical centers will be tested at the UAB Diagnostic Mycoplasma Laboratory to confirm the presence of macrolide resistance using molecular methods developed at UAB to detect gene mutations directly in these clinical specimens. Clinical and lab data will be merged in an electronic database for analysis and used to assess the clinical significance and mode of spread for resistant strains.

"This type of surveillance project is particularly important because there is so little information about the extent of macrolide resistance in the U.S. in such a common respiratory infection for which macrolides such as azithromycin are the first-line treatment," Waites said. "Most clinical laboratories in the U.S. do not offer testing for M. pneumoniae, so treatment is usually given without a confirmed microbiological diagnosis. It is also worrisome that macrolide resistance has increased in Japan and China over the past several years to the extent that more than 90 percent of mycoplasma infections in those countries are caused by macrolide-resistant organisms. We need to know if this resistance is increasing in our country."