Distribution of oral streptococci highly resistant to amoxicillin in dental plaque specimens from Japanese children and adolescents
Distribution of oral streptococci highly resistant to amoxicillin in dental plaque specimens from Japanese children and adolescents
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DOI：
10.1099/jmm.0.027615-0
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发表时间：
2011-12-01
影响因子：
3
通讯作者：
Ooshima, Takashi
中科院分区：
文献类型：
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作者：
Nemoto, Hirotoshi;Nakano, Kazuhiko;Ooshima, Takashi
口腔链球菌是感染性心内膜炎的主要病原体。在进行侵入性牙科治疗时，预防性抗生素通常用于某些类型的心脏病患者，阿莫西林(AMPC)被广泛用于此目的。然而，关于耐AmpC酶口腔链球菌的信息很少。在这里，从253名健康的日本儿童、青少年和青壮年(2-22岁)采集的344个牙菌斑标本被稀释并划线到含有高剂量AmpC的培养基上。使用临床和实验室标准研究所描述的肉汤稀释法对分离菌株的最低抑菌浓度进行了评估。从每个菌株中提取细菌DNA，并将16S rRNA基因的全序列与GenBank中的序列进行比较，以鉴定该物种。结果从14例患者的18份标本中分离出AmpC酶最低抑菌浓度为16mU·g·ml~(-1)的菌株。对这些菌株的16S rRNA基因序列分析表明，它们是主要的口腔链球菌，包括口腔链球菌和微型链球菌。这些发现表明，口腔链球菌对AmpC酶的最低抑菌浓度升高存在于某些小的健康儿童群体中，并强调了进一步研究的必要性，以确定导致此类菌株出现的危险因素。
Oral streptococci are major pathogens of infective endocarditis. Prophylactic antibiotics are commonly given to subjects with certain kinds of heart disorders when invasive dental treatments are performed, with amoxicillin (AMPC) being widely used for this purpose. However, there is little information regarding AMPC-resistant oral streptococci. Here, a total of 344 dental plaque specimens collected from 253 healthy Japanese children, adolescents and young adults (aged 2-22 years) were diluted and streaked onto culture medium containing high-dose AMPC. The MICs for the isolated strains were evaluated using a macrodilution broth method described by the Clinical and Laboratory Standards Institute. Bacterial DNA was extracted from each strain and the entire sequences of the 16S rRNA gene were compared with those in GenBank to identify the species. The results showed that strains with AMPC MICs >16 mu g ml(-1) were isolated from 18 specimens from 14 patients. Analyses of the 16S rRNA gene sequences of these strains identified them as major oral streptococcal species, including Streptococcus oralis and Streptococcus mitis. These findings indicate that oral streptococci with elevated MICs for AMPC exist in certain small populations of healthy children, and highlight the need for further studies to determine risk factors that lead to the appearance of such strains.