Department of Infection Control and Laboratory Diagnostics, Tohoku University Graduate School of Medicine, Sendai, Japan.
J Clin Microbiol. 2013 Nov;51(11):3542-6. doi: 10.1128/JCM.01108-13. Epub 2013 Aug 21.
Acute otitis media (AOM) is the most common upper respiratory tract infection in childhood. Children with AOM were enrolled at Tohoku Rosai Hospital between July 2006 and June 2011 if their middle ear fluid cultures after tympanocentesis yielded only Haemophilus influenzae. The susceptibilities of the isolates to ampicillin were determined, and microtiter biofilm assays and invasion assays using BEAS-2B cells were performed. The association between these bacterial characteristics and clinical relapses of AOM and treatment failures was evaluated. Seventy-four children (39 boys and 35 girls) with a median age of 1 year (interquartile range [IQR], 0.25 to 2 years) were enrolled. Among 74 H. influenzae isolates, 37 showed intermediate resistance or resistance to ampicillin (MIC, ≥ 2 μg/ml). In the microtiter biofilm assay, the median optical density at 600 nm (OD600) was 0.68 (IQR, 0.24 to 1.02), and 70 isolates formed biofilms. The median invasion rate was 15% (IQR, 0 to 10%), and 46 isolates invaded BEAS-2B cells. Relapses and treatment failures occurred in 19 and 6 children, respectively. There was no significant difference in the invasion rates between patients with and those without relapses or treatment failures. Also, there was no significant association between biofilm formation and relapse or treatment failure. The improvements in the severity scores after 1 week were significantly associated with the recovery time (P < 0.0001). We did not identify any significant association between relapse or treatment failure and bacterial factors. AOM has a multifactorial etiology, and this may explain why we could not find a significant association. An improvement in the severity score after 1 week of treatment may be a useful predictor of the outcome of AOM.
急性中耳炎（AOM）是儿童最常见的上呼吸道感染。如果在鼓膜穿刺抽取的中耳液培养仅为流感嗜血杆菌，2006 年 7 月至 2011 年 6 月期间在日本东北大学医院就诊的 AOM 患儿将被纳入研究。测定分离株对氨苄西林的敏感性，并进行微量肉汤生物膜测定和使用 BEAS-2B 细胞的侵袭试验。评估这些细菌特征与 AOM 临床复发和治疗失败之间的关系。共纳入 74 名儿童（39 名男孩和 35 名女孩），中位年龄为 1 岁（四分位距[IQR]，0.25 至 2 岁）。在 74 株流感嗜血杆菌分离株中，37 株对氨苄西林表现出中介耐药或耐药（MIC≥2μg/ml）。在微量肉汤生物膜测定中，600nm 处的中位光密度（OD600）为 0.68（IQR，0.24 至 1.02），70 株形成生物膜。侵袭率的中位数为 15%（IQR，0 至 10%），46 株侵袭 BEAS-2B 细胞。19 名和 6 名患儿分别出现复发和治疗失败。复发和治疗失败患儿的侵袭率无显著差异。生物膜形成与复发或治疗失败之间也没有显著关联。治疗后 1 周严重程度评分的改善与恢复时间显著相关（P<0.0001）。我们没有发现复发或治疗失败与细菌因素之间存在任何显著关联。AOM 的病因是多因素的，这可能解释了我们没有发现显著关联的原因。治疗后 1 周严重程度评分的改善可能是 AOM 结局的有用预测指标。
