背景和目的：急性中耳炎是小孩常見的感染，然而國內仍沒有本土相關微生物分佈資料之研究，本研究主要報告某醫學中心急性中耳炎細菌學與敏感性。研究方法：研究回溯96 株在感染時從中耳取得之細菌學資料。結果：49 個樣本並無培養出細菌，其他47 個樣本產生50 株細菌，Streptococcus pneumoniae 是最常見的菌株（16），之後則為Hemophilus influenzae (13)，敏感性測試顯示對盤尼西林具有抗藥性的Streptococcus pneumoniae (penicillin-resistant Str. pneumoniae, PRSP)佔所有肺炎鏈球菌的73.3%，而對紅黴素具有具有抗藥性的Str. pneumoniae (erythromycin-resistant Str.pneumoniae, ERSP)佔42.9%。就診前使用過抗生素是產生盤尼西林抗藥性肺炎鏈球菌的影響因素(p = 0.03)。結論：肺炎鏈球菌在急性中耳炎中之分佈情形與其他研究類似，如果最初沒有注意抗生素使用於小兒上呼吸道感染，可能會伴隨產生耳朵感染使病情更複雜化。

Acute otitis media (AOM) is a common infection amongchildren. However, there are no domestic data on the distribution of microorganisms. In thisstudy, we report the bacterial etiology of AOM in our institute and their susceptibility toantibiotics. We retrospectively reviewed the bacteriological data for 96 isolatesobtained from middle ear discharges by tympanocentesis during the acute episode of infection. In total, 49 samples revealed nothing, and the other 47 samples yielded 50 isolates ofbacteria. Streptococcus pneumoniae was the most common isolate (16), followed by Hemophilusinfluenzae (13). The susceptibility tests (using a disc-diffusion method, in compliance with theNational Committee for Clinical Laboratory Standards) revealed that penicillin-resistant Str.pneumoniae (PRSP) accounted for 73.3% of all pneumococci, while the erythromycin-resistantstrains (ERSPs) accounted for 42.9% among all Str. pneumoniae isolates.We found that previousantibiotic treatment was a significant risk factor for the occurrence of PRSP (p = 0.03). The frequency of Str. pneumoniae in AOM is similar to what has been reported byothers. Inadvertent initial antibiotics treatment for pediatric upper airway infection maycomplicate the management of concomitant ear infections.