中台灣區域教學醫院之 PCR 陽性肺炎黴漿菌樣本的分子特徵探討

Molecular Characterizations of PCR-positive Mycoplasma pneumoniae Specimens Collected from Central Taiwan

研究目的：肺炎黴漿菌（Mycoplasma pneumoniae）是兒童及成人社區型肺炎的重要致病菌。巨環黴抗生素（Macrolide）一直是治療兒童肺炎黴漿菌感染的首選 用藥。越來越多的研究發現黴漿菌感染也可以造成許多不同程度的嚴重感染甚至死亡，近 10 年來臨床上也發現不少嚴重型或是頑固型感染（refractory Mycoplasma pneumoniae pneumonia, RMPP），包括了產生肺外併發症、發燒及住院天數較長、對於抗生素治療反應失敗等，讓所謂的嚴重型或是頑固型 感染成為臨床醫師的挑戰與研究重點。本研究利用目前幾項重要的序列分析方法來了解從臨床採檢培養出的黴漿菌的分子特徵。

檢體來源與方法：本研究收集中部某區域教學醫院因呼吸道感染住院兒童（<14 歲） 喉頭檢體，我們採用 Multiple-Locus Variable number tandem repeat（VNR）Analysis（MLVA）為分類依據，針對培養陽性肺炎黴漿菌的菌株進行 MLVA 和 P1 基因分型方法以及 23S rRNA（domain V）的基因定序，研究基因型分佈情形和巨環黴素抗藥性比率。

實驗結果：在總共 76 個住院兒童的檢體中有 29 個 Mycoplasma pneumoniae 是 PCR 陽性且順利可培養出來，在這 29 個陽性菌株中發現了 4 種不同的 MLVA類型，分別是 J，P，A 和 X 型。而菌株在 P1 基因分型類型分佈為 P1 有 28 個 （96.6%），屬 P2 只有 1 個（3.4%）。在陽性的 29 個菌株中有 5/29（17.2%）Macrolide resistant 發現了巨環黴素抗藥性抗生素相關突變（2063G）。

結論：本研究表顯示，台灣有多種肺炎黴漿菌基因型在流行，來自社區感染的黴漿 菌巨環黴素抗藥性比率並無顯著增加。

 

Aim: Mycoplasma pneumoniae is one of the most common pathogens for respiratory tract infections in children and adults. Macrolide is the drug of first choice for the treatment of children with Mycoplasma pneumonia infection. However, more and more studies in the past 10 years have found that mycoplasma infection can cause severe pulmonary infections and even deaths. In the present study, we were aimed to investigate molecular characters of culture proven Mycoplasma pneumoniae isolates from a regional hospital in central Taiwan.

Methods: We conducted a cross section study, which enrolled clinical diagnosed MP infected children of ages less than 14-years-old. In addition to serum mycoplasma IgM tests, we exploited polymerase chain reaction and SP4 culture to confirm MP infection. For further investigation, we only characterized culture proven MP isolates by using Multiple-Locus Variable number tandem repeat Analysis (MLVA) and P1 gene typing, and 23S rRNA (domain V) gene sequencing to study genotype distribution and Macrolide resistance rate.

Results: In total, 76 clinical samples were collected and 29 out of them were culture positive. Four different MLVA types were found in 29 positive strains, including J, P, A and X types. Two prevalent MLVA patterns dominated in this study, which were 4-5-7-2 and 4-5-7-3.The P1 gene type distribution accounted for 28 (96.6%) of P1-1 and only 1 (3.4%) of P1-2. Five of the 29 culture positive strains (5/29;17.2%) revealed macrolide resistant mutations (A2063G).

Conclusion: This study showed that MLVA 4-5-7-2 and 4-5-7-3 type MP prevailed in the community in Central Taiwan. The macrolide resistant rate was 17.2%, which is comparable to previous studies.