Background

Expansion of the single sequence type 3 (ST3) was associated with a high macrolide resistance rate among Mycoplasma pneumoniae in Korea during the 2014–2016 epidemic. This study investigates the macrolide resistance rate and genetic diversity of the subsequent epidemic of M. pneumoniae pneumonia in 2019–2020.

Methods

The culture for M. pneumoniae was developed from 1228 respiratory samples collected from children with pneumonia in four hospitals in Korea between January 2019 and January 2020. Determination of macrolide resistance and multilocus sequence typing analysis were performed on M. pneumoniae isolates. eBURST analysis was applied to estimate the relationships among strains and to assign strains to a clonal complex.

Results

M. pneumoniae was cultured in 93 (7.6%) of 1228 clinical samples. The overall macrolide resistance rate of M. pneumoniae strains was 78.5% (73/93). Of the nine STs identified, three were novel. The most common ST was ST3 (66 [71.0%]) followed by ST14 (18 [19.4%]) and ST7/ST15 (2 [2.2%] each). Three STs (ST3, ST14, and ST17) exhibited macrolide resistance. The macrolide resistance rates of ST3 and ST14 were 98.5% (65 of 66) and 38.9% (7 of 18), respectively.

Conclusion

Compared to the previous outbreak in 2014–2016, the overall macrolide resistance remained high; however, an increasing proportion of macrolide resistance was observed within ST14 strains in 2019–2020.

中文翻译：

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2019-2020 年韩国肺炎支原体中大环内酯类药物耐药率持续高企且 ST14 菌株增加

背景

在 2014-2016 年流行期间，单序列 3 型 (ST3) 的扩展与韩国肺炎支原体的高大环内酯类耐药率相关。本研究调查了2019-2020年随后流行的肺炎支原体肺炎的大环内酯类耐药率和遗传多样性。

方法

肺炎支原体培养物是从 2019 年 1 月至 2020 年 1 月期间在韩国四家医院采集的 1228 份肺炎患儿呼吸道样本中开发的。对肺炎支原体分离株进行了大环内酯类耐药性的测定和多位点序列分型分析。eBURST 分析用于估计菌株之间的关系并将菌株分配给克隆复合体。

结果

1228 个临床样本中有 93 个（7.6%）培养了肺炎支原体。肺炎支原体总大环内酯类耐药率为78.5%（73/93）。在确定的九个 ST 中，三个是新的。最常见的 ST 是 ST3 (66 [71.0%])，其次是 ST14 (18 [19.4%]) 和 ST7/ST15 (各 2 [2.2%])。三个 ST（ST3、ST14 和 ST17）表现出对大环内酯类药物的耐药性。ST3 和 ST14 的大环内酯类药物耐药率分别为 98.5%（66 人中的 65 人）和 38.9%（18 人中的 7 人）。

结论

与2014-2016年的上一次疫情相比，大环内酯类耐药性总体保持高位；然而，在 2019-2020 年，在 ST14 菌株中观察到大环内酯类耐药的比例增加。