Macrolide-Resistant Mycoplasma pneumoniae Infections among Children before and during COVID-19 Pandemic, Taiwan, 2017-2023

Abstract

Before the COVID-19 pandemic, Mycoplasma pneumoniae infections emerged during spring to summer yearly in Taiwan, but infections were few during the pandemic. M. pneumoniae macrolide resistance soared to 85.7% in 2020 but declined to 0% during 2022-2023. Continued molecular surveillance is necessary to monitor trends in macrolide-resistant M. pneumoniae.

Keywords: COVID-19; Mycoplasma pneumoniae; SARS; SARS-CoV-2; Taiwan; antimicrobial resistance; bacteria; coronavirus; coronavirus disease; macrolide resistance; molecular epidemiology; multilocus sequence typing; pneumonia; respiratory infections; severe acute respiratory syndrome coronavirus 2; viruses; zoonoses.

Figure 1

Dynamic distribution of macrolide-resistant Mycoplasma pneumoniae infections among children before and during the COVID-19 pandemic, Taiwan, 2017–2023. A) M. pneumoniae infections were detected throughout the year, primarily from March to August. An M. pneumoniae outbreak occurred during 2017–2018. The M. pneumoniae detection rate substantially declined during the COVID-19 pandemic, 2021–2022. Light gray background represents 770 IgM-positive participants; dark gray background represents 209 cases confirmed by culture and PCR. Blue shading indicates timeframe of nonpharmaceutical interventions during the COVID-19 pandemic. B) Among 211 isolates, macrolide resistance was observed in 74 (35.1%) isolates. The resistance rate was 12.5% in 2017, increased to 48.3% in 2018 and to 62.5% in 2019, and reached 85.7% in 2020. Subsequently, the rate decreased to 18.2% in 2021 and dropped to 0% in 2022 and 2023.

Figure 2

Relationships between year of isolation, ST, and genotype distribution in a study of macrolide-resistant Mycoplasma pneumoniae infections among children before and during the COVID-19 pandemic, Taiwan, 2017–2023. A) Macrolide-resistant M. pneumoniae isolates (n = 74) and 5 identified STs: ST3, ST17, ST26, ST33, and ST36. Macrolide resistance substantially decreased after 2021. ST3 was the predominant strain in macrolide-resistant isolates, especially during 2017–2019. B) Macrolide-susceptible M. pneumoniae isolates (n = 135) and 10 identified STs: ST3, ST17, ST9, ST5, ST12, ST20, ST30, ST33, ST39, and ST46. ST17 was the predominant strain during 2017–2019. ST3 was the most common strain and was distributed across all years. C) The relationship between M. pneumoniae CC and ST depicted by goeBURST (https://phyloviz.readthedocs.io/en/latest/data_analysis.html). The data, comprising 144 strains from Taiwan (2017–2023) and previously reported STs (shown in gray) from PubMLST (https://pubmlst.org), demonstrate the genetic relationships within the dataset analyzed by the goeBURST algorithm. The size of each circle is proportional to the number of isolates for each ST, and most STs belonged to CC1, including the leading 2 STs, ST3, and ST17. Green sections indicate M. pneumoniae strains could not be successfully identified using multilocus sequence typing. CC, clonal complex; NT, nontypable; ST, sequence type.