Macrolide Resistance in Mycoplasma pneumoniae, Midwestern United States, 2014 to 2021

Abstract

The epidemiology of macrolide resistance in Mycoplasma (Mycoplasmoides) pneumoniae in the United States is incompletely described. Using a PCR assay targeting common mutations associated with macrolide resistance in M. pneumoniae (23S rRNA gene, A2063G/A2064G), the frequency of macrolide resistance was estimated to be 10% based on analysis of 114 samples tested from January 2014 to September 2021 at Mayo Clinic Laboratories. Seasonality data showed the highest rates of M. pneumoniae infection in the fall/early winter.

Keywords: Mycoplasma pneumoniae; antibiotic resistance; macrolides; pneumonia; surveillance studies.

FIG 1

M. pneumoniae ptsI PCR tests performed from January 2014 through November 2021 showing total numbers of monthly tests performed (blue background) and monthly percent positivity (red line). There was typically a rise in positivity in late fall/winter, except for COVID-19 pandemic times and, to some extent, the 2017–2018 season. Between February 2017 and August 2018, the overall positivity rate was 1% (52/6,238). Peak annual positivity rates were observed in December 2014 (4%), November 2015 (4%), January 2016 (3%), June 2017 (2%), October 2018 (3%), and September 2019 (4%). Macrolide resistant isolates were found in 2014 (n = 1), 2015 (n = 3), 2016 (n = 3), and 2019 (n = 4), but notably, not all specimens testing positive for M. pneumoniae were assessed for macrolide resistance.

FIG 2

Geographic locations of patients testing positive for M. pneumoniae. Shown is the total number of positive tests by state. States shown in gray had no positive results; states shown in dark blue or orange had positive results. Macrolide-resistant M. pneumoniae was detected in states shown in orange, with the percentage of macrolide-resistant M. pneumoniae listed below the specimen numbers.