Respiratory infections due to Mycoplasma pneumoniae bacteria are on the rise.

According to an update from the Centers for Disease Control and Prevention (CDC), cases increased in late spring and have remained high, particularly among young children.

CDC. Mycoplasma Pneumoniae Infections Have Been Increasing. October 18, 2024.

 

“The proportion of patients discharged from emergency departments with a diagnosis of M. pneumoniae-associated pneumonia or acute bronchitis has been increasing over the past six months, peaking in late August,” the CDC stated.

Infections due to M. pneumoniae may cause different symptoms among younger children, including vomiting, wheezing, or diarrhea.

“There can be asymptomatic infection. There can be mildly symptomatic infection. There can be patients who have outpatient pneumonia, and then, more rarely, it can cause serious infection. But certainly we've seen children hospitalized with mycoplasma, and there [have] been infectious complications that occur outside the lungs, also, such as mycoplasma encephalitis, that we've seen,” Dean Blumberg, MD,, Chief of Pediatric Infectious Diseases at UC Davis Children’s Hospital, tells MDLinx.

 

Seasonal increases

 

The CDC estimates that two million infections due to M. pneumoniae occur each year in the United States. as there is no national reporting or surveillance system to track infections of this type, the actual number of people impacted annually is unclear.

CDC. Mycoplasma Pneumoniae Infections Have Been Increasing. October 18, 2024.

 

Infections typically occur in summer and early fall.

“Mycoplasma pneumoniae is an interesting bacteria in that it does have seasonal increases, but they are not as precise as those seasonal increases that we recognize with influenza, for example, which is, of course, a viral infection. So we get periodic, not even annual, surges of mycoplasma infections, particularly, but not exclusively, in younger children, and they occur from year to year for reasons that we're not quite sure of,” William Schaffner, MD, an infectious disease expert at Vanderbilt University School of Medicine, tells MDLinx.

 

A return of mycoplasma infections

 

In 2023, M. pneumoniae infections reemerged around the world following a low incidence of infections since the beginning of the COVID-19 pandemic.

CDC. Mycoplasma Pneumoniae Infections Have Been Increasing. October 18, 2024.

 

The increase in infections among those aged 2 to 4 years could be due to measures taken during the COVID-19 pandemic.

“The explanation might be related to the pandemic in that we built up such a large pool of susceptible school-aged children that then there [was] spillover into other populations. And because of all the social distancing and children staying home from school during the pandemic, there were very few respiratory infections in the community. And because of that, there was a lot of susceptibility that built up over time,” Dr. Blumberg says.

The CDC notes that healthcare providers should consider M. pneumoniae infections as a possible cause of pneumonia and test when appropriate, especially among children who are hospitalized with pneumonia.

CDC. Mycoplasma Pneumoniae Infections Have Been Increasing. October 18, 2024.

 

The CDC also advises that healthcare providers consider swabbing both the nasopharynx and throat to improve the likelihood of detection in respiratory swab specimens.

 

A differential diagnosis

 

Dr. Blumberg notes that since it can be challenging to distinguish infections due to M. pneumoniae from other potential causes of pneumonia, testing is important.

“It can be very difficult to distinguish it from, for example, viral pneumonia or mild or other causes of bacterial pneumonia. That can be a real challenge. So, for any patient that [a doctor is] concerned about, those are the ones that I'd have the lower threshold to refer for testing,” he adds.

“If they do have a positive test and an illness that's clinically compatible, then generally, they're treated with a 5-day course of azithromycin. This can decrease risk of complications, and they can recover faster. But, in addition, it's worthwhile to know because if the patients are sick for a while, then there's going to be a differential diagnosis, and knowing what the pathogen is, knowing what the clinical course might be, is very useful in terms of communicating with the family,” Dr. Blumberg says.

 What this means for you

Respiratory infections due to Mycoplasma pneumoniae have been on the rise since late spring and remain high. Notably, there has been an increase among young children aged 2 to 4 years. The CDC says that healthcare providers need to be aware of Mycoplasma pneumoniae as a possible cause of pneumonia and test when indicated.